We develop the theory of n-stacks (or more generally Segal n-stacks which are∞-stacks such that the morphisms are invertible above degree n). This is done by systematically using the theory of closed model categories (cmc). Our main results are: a definition of n-stacks in terms of limits, which should be perfectly general for stacks of any type of objects; several other characterizations of n-...

Offset plane wave migration and common-azimuth migration are among the most promising wave-equation migration methods for efficiently imaging 3-D marine data sets. Offset plane wave migration has some computational advantages over common-azimuth migration, but common-azimuth is more accurate. Sub-salt images produced by commonazimuth migration are better focused than the corresponding images pr...

Least-squares reverse-time migration (LSRTM) provides image of reflectivity with high resolution and compensated amplitude, but the computational cost is extremely high. One way to improve efficiency is to encode all of shot gathers into one or several super-shot gathers with designed encoding functions so as to solve a smaller number of wave-equations at each iteration. Another way is to use d...

A reconfigurable computing (RC) platform called SPACE (Seismic data Processing Accelerator with reConfigurable Engine) is proposed to accelerate the execution of 3D prestack Kirchhoff time migration (PSTM) based on the optimized 6 order NMO Correction technology (Sun et. al. 2002). Our simulations demonstrated up to 22 X performance improvement on the proposed RC platform comparing with the pur...

Wave-equation migration is an accurate and robust alternative to Kirchhoff migration when multipathing and other complex wave phenomena occur, such as in subsalt exploration. In these situations, images obtained by wave-equation migration are often superior to images obtained by Kirchhoff methods. However, 3-D wave-equation prestack imaging is an immature technology compared with Kirchhoff imag...