Gaurav Dutta

Sparse least-squares reverse time migration using seislets

Abstract I propose an approach for sparse least-squares reverse time migration (LSRTM) using seislets as a basis for the reflectivity distribution. This basis is used along with a dip-constrained preconditioner that emphasizes image updates only along prominent dips during the least-squares iterations. These dips can be estimated from the standard migration image or from the gradient using plane-wave destruction filters or structural tensors. Numerical tests on synthetic and field datasets demonstrate the benefits of this method for mitigation of aliasing artifacts and crosstalk noise in multisource least-squares migration.

Extension of Seismic Scanning Tunneling Macroscope to Elastic Waves

The theory for the seismic scanning tunneling macroscope is extended from acoustic body waves to elastic body-wave propagation. We show that, similar to the acoustic case, near-field superresolution imaging from elastic body waves results from the O(1/R) term, where R is the distance between the source and near-field scatterer. The higher-order contributions

Subwavelength imaging using seismic scanning tunneling macroscope: Field data example

R^{-n}

Wave-equation Q tomography

R-n for

Making the most out of the least (squares migration)

n>1

Skeletonized wave-equation inversion for Q

n>1 are cancelled in the near-field region for a point source with normal stress.