We present a new 2-D traveltime tomography method for the inversion of densely sampled seismic streamer data. This method was especially designed for the efficient inversion of long-offset multichannel data. A layer-interface model is used to fit ray-traced traveltime data to observed seismic data. The solution of the forward problem is based on initial-value ray tracing in a triangulated grid with a linear interpolation of the squared slowness. We implement an adaptive model parametrization based on ray density, which allows for smaller velocity cells with subsequent iteration steps. We solve the inverse problem using an iterative linearized joint inversion of reflection and refraction data for interface and velocity structures. Adaptive smoothing regularization is implemented in the form of a priori model covariances. As the cell sizes decrease with increasing iteration numbers, the model covariance ranges are reduced, allowing for more detail to emerge in the model. We demonstrate the algorithm's ability to invert successfully a realistic crustal velocity structure in a synthetic model. Several adaptive and non-adaptive model parametrizations are tested. The joint interface and velocity inversion of real long-offset reflection and refraction traveltime data is presented as a second example. We demonstrate that our results are in good agreement with independently derived velocity models.
Geophys. J. Int.ISI Document Delivery No.: 905TKTimes Cited: 1Cited Reference Count: 51Cited References:BISHOP TN, 1985, GEOPHYSICS, V50, P903BOHM G, 1996, J SEISM EXPLOR, V5, P169BOHM G, 2000, GEOPHYS PROSPECT, V48, P723BOSCH M, 2002, 64 M EAGE EXP ABSTR, P174BOSCH M, 2002, TRAVEL TIME TOMOGRAP, P43CERVENY V, 2001, SEISMIC RAY THEORYCOX B, 2001, EAGE EXP ABSTR 63 M, M35DUBRULE O, 2003, GEOSTATISTICS SEISMIENGLAND RW, 1997, J GEOL SOC LONDON 3, V154, P497FAILLY M, 1993, GEOPHYS J INT, V115, P410FALETIC R, 1997, THESIS AUSTR NATL UFARRA V, 1990, GEOPHYS J INT, V103, P341FORTUNE S, 1987, ALGORITHMICA, V2, P153FREUDENREICH Y, 2002, THESIS U CAMBRIDGE CHALE D, 1991, CWP107 COL SCH MINHOBRO J, 1999, THESIS U CAMBRIDGE CHOBRO JWD, 2003, GEOPHYS J INT, V152, P79HOFF K, 1996, COMP236 U N CAR CHAPHUA B, 1995, ACTO GEOPHYS J, V38, P750HUBRAL P, 1980, INTERVAL VELOCITIESINDIRA NK, 1998, INVERSE METHODS GENISAAKS EH, 1989, INTRO APPL GEOSTATISJOPPEN M, 1990, J GEOPHYS RES-SOLID, V95, P19821KISSLING E, 2001, PHYS EARTH PLANET IN, V123, P89KORENAGA J, 1997, J GEOPHYS RES-SOL EA, V102, P15345KORMENDI F, 1991, GEOPHYSICS, V56, P664LUTTER WJ, 1994, GEOPHYSICS, V59, P1278MCCAUGHEY M, 1995, THESIS U CAMBRIDGE CMCCAUGHEY M, 1997, GEOPHYS J INT, V131, P87MOSEGAARD K, 1995, J GEOPHYS RES-SOL EA, V100, P12431MUIR F, 1985, SEP, V44, P55PHILLIPS WS, 1991, GEOPHYSICS, V56, P1639PRATT GR, 2002, J C ABSTR, V7, P181PRATT RG, 1996, GEOPHYS J INT, V124, P323PRESS WH, 1992, NUMERICAL RECIPES CROBERTS DG, 1999, PETROLEUM GEOLOGY NW, V1, P7SAMBRIDGE M, 1995, GEOPHYS J INT, V122, P837SCALES JA, 1987, GEOPHYSICS, V52, P179SCALES JA, 1997, INTRO GEOPHYS INVERSSHERIFF RE, 1995, EXPLORATION SEISMOLOSHIPP RM, 2002, GEOPHYS J INT, V151, P325SHIRLEY P, 1992, RAY TRACING NEWS, V5SOUPIOS PM, 1999, 2 BALK GEOPH C EXH B, P10TARANTOLA A, 1982, J GEOPHYS-Z GEOPHYS, V50, P159TARANTOLA A, 1987, SEISMIC TOMOGRAPHY, P135VESNAVER A, 1994, J SEISM EXPLOR, V3, P323WESSEL P, 1991, EOS T AM GEOPHYS UN, V72, P441YILMAZ O, 1987, SEISMIC DATA PROCESSZEEV N, 2001, 63 M EAGEZELT CA, 1992, GEOPHYS J INT, V108, P16ZELT CA, 1998, J GEOPHYS RES-SOL EA, V103, P7187