A method for non-orthogonal seismic polarization-vector separation

SUMMARY With the exception of the first arriving of P wave, it is difficult to make an accurate measurement of parameters such as arrival time, phase, amplitude, polarization and the waveform of later-arriving phases on three-component, high-frequency records. This is due to the mutual interference of partially overlapping phases. Most methods of studying two-component or/and three-component seismograms assume that body-wave polarizations are mutually orthogonal. This is not correct, however, in cases of anisotropic or inhomogeneous medium; nor can it be used to measure converted phases or phases reflected along different paths. To solve such problems, this paper presents a new technique called Seismic Polarization-Vector Separation (SPVS). Using an affine coordinate transform, SPVS achieves a more accurate and reliable measurement of almost all kinematic and dynamic parameters on three-component seismograms, including polarization, arrival time, amplitude and extended waveform. As a consequence, it succeeds in separating and reconstructing the phase sequence of body waves on three-component seismograms without data loss.

[1]  S. Crampin,et al.  Evidence for anisotropy in the upper mantle beneath Eurasia from the polarization of higher mode seismic surface waves , 1977 .

[2]  S. Crampin,et al.  Polarizations of reflected shear waves , 1990 .

[3]  Pascal Bernard,et al.  Seismic anisotropy around the Gulf of Corinth, Greece, deduced from three‐component seismograms of local earthquakes and its relationship with crustal strain , 1996 .

[4]  Michael E. Wysession,et al.  Shear wave splitting, continental keels, and patterns of mantle flow , 2000 .

[5]  J. Chiu,et al.  Polarization analysis of high-frequency, three-component seismic data , 1991, Bulletin of the Seismological Society of America.

[6]  E. A. Flinn.  Signal analysis using rectilinearity and direction of particle motion , 1965 .

[7]  V. Schulte‐Pelkum,et al.  A synthesis of seismic P and S anisotropy , 2003 .

[8]  L. P. Vinnik,et al.  Detection of waves converted from P to SV in the mantle , 1977 .

[9]  S. Crampin,et al.  Extracting shear wave polarizations from different source orientations: Synthetic modelling , 1990 .

[10]  Weijian Mao,et al.  Polarization filtering for automatic picking of seismic data and improved converted phase detection , 2001 .

[11]  S. Crampin.  SUGGESTIONS FOR A CONSISTENT TERMINOLOGY FOR SEISMIC ANISOTROPY , 1989 .

[12]  Ernest R. Kanasewich,et al.  Enhancement of Teleseismic Body Phases with a Polarization Filter , 1970 .

[13]  Zhang,et al.  Experimental study on the P wave velocity in rocks from lower crust and crust-mantle transitional zone beneath the Hannuoba , 2002 .

[14]  C. Yao,et al.  SHEAR-WAVE POLARIZATION AND CRACK INDUCED ANISOTROPY OF UPPER CRUST IN LULONG, NORTH CHINA , 1992 .

[15]  David C. Booth,et al.  Shear-wave polarizations near the North Anatolian Fault – II. Interpretation in terms of crack-induced anisotropy , 1985 .

[16]  J. Lavé,et al.  How to relate body wave and surface wave anisotropy , 2000 .

[17]  S. Crampin,et al.  Shear-wave polarizations near the North Anatolian Fault – I. Evidence for anisotropy-induced shear-wave splitting , 1985 .

[18]  J. Gaiser.  Applications for vector coordinate systems of 3-D converted-wave data , 1999 .

[19]  L. Vinnik,et al.  Heterogeneities in the mantle transition zone from observations of P-to-SV converted waves , 1983 .

[20]  Frank L. Vernon,et al.  Frequency dependent polarization analysis of high‐frequency seismograms , 1987 .

[21]  Paul G. Richards,et al.  Seismological evidence for differential rotation of the Earth's inner core , 1996, Nature.

[22]  Herbert F. Wang,et al.  Depth variation of seismic anisotropy and petrology in central European lithosphere: A tectonothermal synthesis from spinel lherzolite , 2001 .

[23]  Shear wave polarization anisotropy observed in a rift zone in Japan , 1989 .

[24]  Paul G. Silver,et al.  Seismic anisotropy of oceanic upper mantle: Shear wave splitting methodologies and observations , 1998 .

[25]  Stuart Crampin,et al.  Linear‐transform techniques for processing shear‐wave anisotropy in four‐component seismic data , 1993 .

[26]  Colin MacBeth,et al.  Interpreting non‐orthogonal split shear waves for seismic anisotropy in multicomponent VSPS , 1998 .

[27]  Stuart Crampin,et al.  A decade of shear-wave splitting in the Earth's crust: what does it mean? what use can we make of it? and what should we do next? , 1991 .

[28]  S. Crampin.  Geological and industrial implications of extensive-dilatancy anisotropy , 1987, Nature.

[29]  Gemma Musacchio,et al.  Polarization filter with singular value decomposition , 2001 .

[30]  M. Ando,et al.  S-wave anisotropy in the upper mantle under a volcanic area in Japan , 1980, Nature.

[31]  Stuart Crampin,et al.  Seismic-wave propagation through a cracked solid: polarization as a possible dilatancy diagnostic , 1978 .

[32]  J. C. Samson,et al.  Data‐adaptive polarization filters for multichannel geophysical data , 1981 .

[33]  A. Jurkevics.  Polarization analysis of three-component array data , 1988 .