Effect of wave-inclusion interactions in the crosshole tomographic imaging of heterogeneous media

This paper describes a series of physical and numerical experiments designed to evaluate elastic wave-inclusion interactions and the ability of crosshole travel-time tomography to detect anomalies in heterogeneous media. The effects of diffraction-driven time delays on wave propagation detection methodologies are considered using a simple circular Plexiglas plate with a carved slot. Then, the quality of the tomographic inversion for different wavelengths to ray-path lengths and anomaly size ratios are tested using a rectangular Plexiglas plate containing a circular cavity. Guidelines for establishing the proper measurement configuration are developed based on the observed wave-inclusion interactions. Finally, numerical simulations are performed to extend the proposed guidelines for stress-dependent field applications. The simulated results show that crosshole travel-time tomography, with a measurement configuration (e.g., choice of wavelength and ray-path length) considering diffraction phenomena, can detect the size of an anomaly in a stress-dependent heterogeneous medium with a 10% error.

[1]  Daryl R. Tweeton,et al.  3DTOM, Three-Dimensional Geophysical Tomography , 1996 .

[2]  Andreas Becht,et al.  Inversion strategy in crosshole radar tomography using information of data subsets , 2004 .

[3]  K. Graff.  Wave Motion in Elastic Solids , 1975 .

[4]  J. Lysmer,et al.  Finite Element Method Accuracy for Wave Propagation Problems , 1973 .

[5]  G. Kitagawa,et al.  An experimental study of phase angle fluctuation in seismic waves in random heterogeneous media: time-series analysis based on multivariate AR model , 2007 .

[6]  J. Virieux.  P-SV wave propagation in heterogeneous media: Velocity‐stress finite‐difference method , 1986 .

[7]  Jianghai Xia,et al.  Near Surface Tunnel Detection Using Diffracted P-waves: a Feasibility Study , 2007 .

[8]  F. Boschetti,et al.  A fractal-based algorithm for detecting first arrivals on seismic traces , 1996 .

[9]  Ettore Cardarelli,et al.  Evaluation of tunnel stability using integrated geophysical methods , 2003 .

[10]  J. Santamarina,et al.  Soils and waves:Particulate materials behavior, characterization and process monitoring , 2001 .

[11]  A. R. Gregory,et al.  ELASTIC WAVE VELOCITIES IN HETEROGENEOUS AND POROUS MEDIA , 1956 .

[12]  J. Santamarina,et al.  Design Criteria for Geotomographic Field Studies , 2003 .

[13]  Tapan Mukerji,et al.  Scale effects on velocity dispersion: From ray to effective medium theories in stratified media , 1994 .

[14]  Dual tomography for imaging complex structures , 1991 .

[15]  S. Ivansson,et al.  Seismic borehole tomography—Theory and computational methods , 1986, Proceedings of the IEEE.

[16]  Griffiths,et al.  Compressional‐ and shear‐wave velocities as a function of confining stress in dry sandstones , 1999 .

[17]  K. Helbig.  Anisotropy and dispersion in periodically layered media , 1984 .

[18]  Surface‐to‐tunnel seismic tomography studies at Yucca Mountain, Nevada , 2004 .

[19]  Louise Pellerin,et al.  Tools for electromagnetic investigation of the shallow subsurface , 1997 .

[20]  Thomas C. Sheahan,et al.  S-Wave Velocity Tomography: Small-Scale Laboratory Application , 2005 .

[21]  J. Santamarina,et al.  Shear wave propagation in jointed rock: state of stress , 2002 .

[22]  R. Carlson,et al.  An experimental test of P-wave anisotropy in stratified media , 1984 .

[23]  D. Fratta,et al.  Travel-time tomographic imaging: multi-frequency diffraction evaluation of a medium with a high-contrast inclusion , 2010 .

[24]  T. Mukerji,et al.  Scale-dependent seismic velocity in heterogeneous media , 1995 .

[25]  Mike Ashworth,et al.  Advective controls on primary production in the stratified western Irish Sea: An eddy-resolving model study , 2004 .

[26]  S. Greenhalgh,et al.  Non-linear inversion travel-time tomography: imaging high-contrast inhomogeneities , 1992 .

[27]  M. J. Jackson,et al.  3DTOM: Three-dimensional geophysical tomography. Report of investigations/1996 (Final) , 1996 .

[28]  J. Berryman,et al.  Fermat's principle and nonlinear traveltime tomography. , 1989, Physical review letters.

[29]  T. Mukerji,et al.  The Rock Physics Handbook , 1998 .

[30]  G. Backus.  Long-Wave Elastic Anisotropy Produced by Horizontal Layering , 1962 .

[31]  Dante Fratta,et al.  Tomographic Detection of Low-Velocity Anomalies with Limited Data Sets (Velocity and Attenuation) , 2000 .

[32]  C. H. Chapman,et al.  Crosshole seismic tomography , 1989 .

[33]  J. Carcione,et al.  Long-wave anisotropy in stratified media: A numerical test , 1991 .

[34]  Geotechnical tomography: the effects of diffraction , 1993 .

[35]  Clifford H. Thurber,et al.  A fast algorithm for two-point seismic ray tracing , 1987 .