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A M Dziewonski - One of the best experts on this subject based on the ideXlab platform.

  • global seismicity of 2001 centroid moment tensor solutions for 961 Earthquakes
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: Goran Ekstrom, A M Dziewonski, N N Maternovskaya, Meredith Nettles
    Abstract:

    Abstract Centroid-moment tensor (CMT) solutions are presented for 961 Earthquakes occurring during 2001. The solutions are obtained using corrections for aspherical Earth Structure represented by the whole-mantle shear-velocity model SH8/U4L8 of Dziewonski and Woodward [A.M. Dziewonski, R.L. Woodward, Acoustic imaging at the planetary scale, in: H. Emert, H.-P. Harjes (Eds.), Acoustical Imaging, vol. 19, Plenum Press, New York, 1992, pp. 785–797]. The model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for january to march 1998
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor (CMT) solutions are presented for 204 Earthquakes that occurred during the first quarter of 1998. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [Dziewonski, A.M., Woodward, R.L., 1992. Acoustic imaging at the planetary scale. In: Emert, H., Harjes, H.-P. (Eds.), Acoustical Imaging, vol. 19. Plenum Press, New York, pp. 785–797]. A model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for october december 2000
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor solutions are presented for 263 Earthquakes that occurred during the fourth quarter of 2000. The solutions are obtained using corrections for a spherical Earth Structure represented by the whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [A.M. Dziewonski, R.L. Woodward, Acoustic imaging at the planetary scale, in: H. Emert, H.-P. Harjes (Eds.), Acoustical Imaging, Plenum Press, New York, vol. 19, 1992, pp. 785–797]. The model of an elastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for july september 1997
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor solutions are presented for 209 Earthquakes that occurred during the third quarter of 1997. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [Acoustic imaging at the planetary scale, in: H. Emert, H.-P. Harjes (Eds.), Acoustical Imaging, vol. 19, Plenum Press, New York, pp. 785–797]. A new model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for july september 2000
    Physics of the Earth and Planetary Interiors, 2001
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor (CMT) solutions are presented for 308 Earthquakes that occurred during the third quarter of 2000. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [Acoustical Imaging, Vol. 19, Plenum Press, New York, 1992, p. 785]. A model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the wave forms.

M P Salganik - One of the best experts on this subject based on the ideXlab platform.

  • centroid moment tensor solutions for july september 1996
    Physics of the Earth and Planetary Interiors, 1997
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya, M P Salganik
    Abstract:

    Abstract Centroid-moment tensor solutions are presented for 252 Earthquakes that occured during the third quarter of 1996. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8. A new model of anelastic attenuation is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for april june 1996
    Physics of the Earth and Planetary Interiors, 1997
    Co-Authors: A M Dziewonski, Goran Ekstrom, M P Salganik
    Abstract:

    Abstract Centroid-moment tensor solutions are presented for 199 Earthquakes that occurred during the second quarter of 1996. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward (1992) (in: H. Emert and H.-P. Harjes (Editors), Acoustical Imaging, Vol. 19, Plenum, pp. 785–797). A new model of anelastic attenuation by Durek and Ekstrom (1996) (Bull. Seismol. Soc. Am., 86: 144–158) is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for january march 1996
    Physics of the Earth and Planetary Interiors, 1997
    Co-Authors: A M Dziewonski, Goran Ekstrom, M P Salganik
    Abstract:

    Abstract Centroid-moment tensor solutions are presented for 212 Earthquakes that occurred during the first quarter of 1996. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward (1992, in: H. Emert and H.-P. Harjes (Editors), Acoustical Imaging , Plenum Press). A new model of anelastic attenuation of Durek and Ekstrom (1996, Bull. Seismol. Soc. Am. , 86: 144–158) is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for october december 1995
    Physics of the Earth and Planetary Interiors, 1997
    Co-Authors: A M Dziewonski, Goran Ekstrom, M P Salganik
    Abstract:

    Abstract Centroid-moment tensor solutions are presented for 219 Earthquakes that occurred during the fourth quarter of 1995. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward (1992). A new model of anelastic attenuation of Durek and Ekstrom (1996) is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for april june 1995
    Physics of the Earth and Planetary Interiors, 1996
    Co-Authors: A M Dziewonski, Goran Ekstrom, M P Salganik
    Abstract:

    Centroid-moment tensor solutions are presented for 277 Earthquakes that occurred during the second quarter of 1995. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8U4L8 of Dziewonski and Woodward (1992) (Acoustical Imaging, Vol. 19, pp. 785–797). A new model of anelastic attenuation of Durek and Ekstrom (1994) (EOS, 75: 83) is used to predict the decay of the waveforms.

Goran Ekstrom - One of the best experts on this subject based on the ideXlab platform.

  • global seismicity of 2001 centroid moment tensor solutions for 961 Earthquakes
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: Goran Ekstrom, A M Dziewonski, N N Maternovskaya, Meredith Nettles
    Abstract:

    Abstract Centroid-moment tensor (CMT) solutions are presented for 961 Earthquakes occurring during 2001. The solutions are obtained using corrections for aspherical Earth Structure represented by the whole-mantle shear-velocity model SH8/U4L8 of Dziewonski and Woodward [A.M. Dziewonski, R.L. Woodward, Acoustic imaging at the planetary scale, in: H. Emert, H.-P. Harjes (Eds.), Acoustical Imaging, vol. 19, Plenum Press, New York, 1992, pp. 785–797]. The model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for january to march 1998
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor (CMT) solutions are presented for 204 Earthquakes that occurred during the first quarter of 1998. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [Dziewonski, A.M., Woodward, R.L., 1992. Acoustic imaging at the planetary scale. In: Emert, H., Harjes, H.-P. (Eds.), Acoustical Imaging, vol. 19. Plenum Press, New York, pp. 785–797]. A model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for october december 2000
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor solutions are presented for 263 Earthquakes that occurred during the fourth quarter of 2000. The solutions are obtained using corrections for a spherical Earth Structure represented by the whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [A.M. Dziewonski, R.L. Woodward, Acoustic imaging at the planetary scale, in: H. Emert, H.-P. Harjes (Eds.), Acoustical Imaging, Plenum Press, New York, vol. 19, 1992, pp. 785–797]. The model of an elastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for july september 1997
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor solutions are presented for 209 Earthquakes that occurred during the third quarter of 1997. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [Acoustic imaging at the planetary scale, in: H. Emert, H.-P. Harjes (Eds.), Acoustical Imaging, vol. 19, Plenum Press, New York, pp. 785–797]. A new model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for july september 2000
    Physics of the Earth and Planetary Interiors, 2001
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor (CMT) solutions are presented for 308 Earthquakes that occurred during the third quarter of 2000. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [Acoustical Imaging, Vol. 19, Plenum Press, New York, 1992, p. 785]. A model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the wave forms.

N N Maternovskaya - One of the best experts on this subject based on the ideXlab platform.

  • centroid moment tensor solutions for july september 1997
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor solutions are presented for 209 Earthquakes that occurred during the third quarter of 1997. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [Acoustic imaging at the planetary scale, in: H. Emert, H.-P. Harjes (Eds.), Acoustical Imaging, vol. 19, Plenum Press, New York, pp. 785–797]. A new model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • global seismicity of 2001 centroid moment tensor solutions for 961 Earthquakes
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: Goran Ekstrom, A M Dziewonski, N N Maternovskaya, Meredith Nettles
    Abstract:

    Abstract Centroid-moment tensor (CMT) solutions are presented for 961 Earthquakes occurring during 2001. The solutions are obtained using corrections for aspherical Earth Structure represented by the whole-mantle shear-velocity model SH8/U4L8 of Dziewonski and Woodward [A.M. Dziewonski, R.L. Woodward, Acoustic imaging at the planetary scale, in: H. Emert, H.-P. Harjes (Eds.), Acoustical Imaging, vol. 19, Plenum Press, New York, 1992, pp. 785–797]. The model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for october december 2000
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor solutions are presented for 263 Earthquakes that occurred during the fourth quarter of 2000. The solutions are obtained using corrections for a spherical Earth Structure represented by the whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [A.M. Dziewonski, R.L. Woodward, Acoustic imaging at the planetary scale, in: H. Emert, H.-P. Harjes (Eds.), Acoustical Imaging, Plenum Press, New York, vol. 19, 1992, pp. 785–797]. The model of an elastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for january to march 1998
    Physics of the Earth and Planetary Interiors, 2003
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor (CMT) solutions are presented for 204 Earthquakes that occurred during the first quarter of 1998. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [Dziewonski, A.M., Woodward, R.L., 1992. Acoustic imaging at the planetary scale. In: Emert, H., Harjes, H.-P. (Eds.), Acoustical Imaging, vol. 19. Plenum Press, New York, pp. 785–797]. A model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the waveforms.

  • centroid moment tensor solutions for july september 2000
    Physics of the Earth and Planetary Interiors, 2001
    Co-Authors: A M Dziewonski, Goran Ekstrom, N N Maternovskaya
    Abstract:

    Abstract Centroid-moment tensor (CMT) solutions are presented for 308 Earthquakes that occurred during the third quarter of 2000. The solutions are obtained using corrections for aspherical Earth Structure represented by a whole mantle shear velocity model SH8/U4L8 of Dziewonski and Woodward [Acoustical Imaging, Vol. 19, Plenum Press, New York, 1992, p. 785]. A model of anelastic attenuation of Durek and Ekstrom [Bull. Seism. Soc. Am. 86 (1996) 144] is used to predict the decay of the wave forms.

Po Chen - One of the best experts on this subject based on the ideXlab platform.

  • Full-Wave Seismic Data Assimilation: Theoretical Background and Recent Advances
    Pure and Applied Geophysics, 2011
    Co-Authors: Po Chen
    Abstract:

    The seismological inverse problem has much in common with the data assimilation problem found in meteorology and oceanography. Using the data assimilation methodology, I will formulate the seismological inverse problem for estimating seismic source and Earth Structure parameters in the form of weak-constraint generalized inverse, in which the seismic wave equation and the associated initial and boundary conditions are allowed to contain errors. The resulting Euler–Lagrange equations are closely related to the adjoint method and the scattering-integral method, which have been successfully applied in full-3D, full-wave seismic tomography and Earthquake source parameter inversions. I will review some recent applications of the full-wave methodology in seismic tomography and seismic source parameter inversions and discuss some challenging issues related to the computational implementation and the effective exploitation of seismic waveform data.

  • Rapid Full-Wave Centroid Moment Tensor (CMT) Inversion in a Three-Dimensional Earth Structure Model for Earthquakes in Southern California
    Geophysical Journal International, 2011
    Co-Authors: En Jui Lee, Po Chen, Thomas H. Jordan, Liqiang Wang
    Abstract:

    SUMMARY A central problem of seismology is the inversion of regional waveform data for models of Earthquake sources. In regions such as Southern California, preliminary 3-D Earth Structure models are already available, and efficient numerical methods have been developed for 3-D anelastic wave-propagation simulations. We describe an automated procedure that utilizes these capabilities to derive centroid moment tensors (CMTs). The procedure relies on the use of receiver-side Green’s tensors (RGTs), which comprise the spatial-temporal displacements produced by the three orthogonal unit impulsive point forces acting at the receivers. We have constructed a RGT database for 219 broad-band stations in Southern California using a tomographically improved version of the 3-D SCEC Community Velocity Model Version 4.0 (CVM4) and a staggered-grid finite-difference code. Finite-difference synthetic seismograms for any Earthquake in our modelling volume can be simply calculated by extracting a small, source-centred volume from the RGT database and applying the reciprocity principle. The partial derivatives needed for the CMT inversion can be generated in the same way. We have developed an automated algorithm that combines a grid-search for suitable focal mechanisms and hypocentre locations with a Gauss–Newton optimization that further refines the grid-search results. Using this algorithm, we have determined CMT solutions for 165 small to medium-sized Earthquakes in Southern California. Preliminary comparison with the CMT solutions provided by the Southern California Seismic Network (SCSN) shows that our solutions generally provide better fit to the observed waveforms. When applied to a large number of Earthquakes, our algorithm may provide a more robust CMT catalogue for Earthquakes in Southern California.

  • resolving fault plane ambiguity for small Earthquakes
    Geophysical Journal International, 2010
    Co-Authors: Po Chen, Thomas H. Jordan, Li Zhao
    Abstract:

    SUMMARY We have developed an automated procedure to resolve fault-plane ambiguity for small to medium-sized Earthquakes (2.5 ≤ML≤ 5) using synthetic Green's tensors computed in a 3-D Earth Structure model and applied this procedure to 35 Earthquakes in the Los Angeles area. For 69 per cent of the events, we resolved fault plane ambiguity of our CMT solutions at 70 per cent or higher probability. For some Earthquakes, the fault planes selected by our automated procedure were confirmed by the distributions of relocated aftershock hypocentres. In regions where there are no precisely relocated aftershocks or for Earthquakes with few aftershocks, we expect our method to provide the most convenient means for resolving fault plane ambiguity. Our procedure does not rely on detecting directivity effects; therefore it is applicable to any types of Earthquakes.

  • frechet kernels for imaging regional Earth Structure based on three dimensional reference models
    Bulletin of the Seismological Society of America, 2005
    Co-Authors: Li Zhao, Thomas H. Jordan, Kim B Olsen, Po Chen
    Abstract:

    High-resolution images of three-dimensional (3D) seismicStructuresare not only of scientific interest, but also of practical importance in predicting strong ground motion after large Earthquakes. Given the source and station distributions, resolutions in current regional seismic tomography studies have been limited by two types of simplifying practices: the adoption of high-frequency approximations such as the ray theory and the use of one-dimensional (1D) reference (starting) models. We have developed a new approach to compute accurate finite-frequency 3D Frechet (sensitivity) kernels of observed travel time and amplitude anomalies relative to 3D reference models. In our approach, we use a fourth-order staggered-grid finite- difference method to model the seismic-wave propagation in 3D media, and the reciprocity property of the Green's tensor to reduce the number of numerical simu- lations. This approach accounts for the perturbations in compressional- and shear- wave speeds in the same way, leading to a capability of inverting for the shear-wave speed directly from seismic data. The algorithm is readily parallelized to allow for realistic regional high-resolution 3D tomography inversions. We have implemented the algorithm for the Southern California Earthquake Center (SCEC) Community Velocity Model, SCEC CVM 3.0, a complex 3D model for Southern California in- cluding a number of sedimentary basins. By enabling the inversion of 3D structural perturbations to 3D reference models, our approach provides a practical means of iteratively solving the nonlinear regional tomography problems.

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