HR: 16:15h
AN: S44A-04 INVITED     [Abstracts]
TI: Kinematics of Reverse Time Imaging
AU: * Symes, W W
EM: symes@caam.rice.edu
AF: Rice University, 6100 Main St., Houston, TX 77005 United States
AB: Prestack depth migration produces image gathers, which present the kinematic information implicit in seismic data in the form of redundant images of the subsurface. Most effective velocity estimation techniques rely on analysis of image gathers. This talk will describe a computation of image gathers using the full ("two-way") wave equation, known as reverse time imaging, in which the redundant parameter in the image is (subsurface) offset. Similar computations are routinely accomplished using depth extrapolation ("one-way" wave equation). Amongst other advantages, the two-way computation avoids the aperture limitation inherent in the one-way approach. Analysis also shows that two-way reverse time image gathers are free of kinematic artifacts (energetic events not corresponding to actual reflectors), at least near zero (subsurface) offset. Such kinematic artifacts often contaminate other forms of prestack imaging. This new construction of image gathers may provide a basis for reliable velocity analysis, hence imaging, in regions of severe refraction. such as gas chimneys and partial melts.
DE: 3210 Modeling
DE: 3230 Numerical solutions
DE: 3260 Inverse theory
DE: 7203 Body wave propagation
DE: 7260 Theory and modeling
SC: Seismology [S]
MN: 2005 Joint Assembly