Research Interests of Ru-Shan Wu

RESEARCH INTERESTS OF RU-SHAN WU

THEORETICAL SEISMOLOGY, GEOPHYSICAL WAVE SCATTERING & IMAGING

The classic earth model is undergoing a revolutionary change: from a static, layered structure to a kinematic/dynamic, laterally heterogeneous model. The earth has been revealed to have hierarchical, multi-scaled heterogeneities everywhere. More heterogeneous the place is, more interesting processes (subduction, collision, accretion) can be found around that place. Seismology played and is still playing an important role in the movement. The introduction of broad-band and multi-component seismometers, installation of various seismic networks and arrays (from global, regional and local networks, to small aperture arrays), digital recording and networking, etc. have tremendously increased the data amount and quality available to seismological community. Combined with even faster progress of super-computing and parallel precessing, the opportunity of discoveries and contributions in front of seismologists are ever greater than before. Ru-Shan Wu's interest is to advance wave propagation and scattering theory and high-resolution geophysical imaging methods (diffraction and scattering tomography), and taking the full advantage of the new development in data acquisition and computing capacity, to join the adventure of penetrating the earth and discovering new features.

Wu and his colleagues have studied the small-scale heterogeneities in the crust and upper mantle and their statistical characteristics (modeled as random media) directly (from well-logging data) and indirectly (from seismic wave scattering). He has developed new theories and methods on elastic wave propagation and scattering in complex earth media, on separation scattering effect from intrinsic attenuation, on whole seismogram synthetics, and on diffraction and scattering tomography. He has obtained the power spectra, fractal dimensions and other statistical parameters of lithospheric heterogeneities in several regions of the world and is studying the relation of fractals & chaos to tectonic/geodynamic processes. Influences of diffraction/scattering and random scattering by small-scale heterogeneities to tomography of large-scale structures are also in Wu's research topics.

CURRENT RESEARCH INTERESTS:

Seismic imaging (including prestack and poststack depth migrations) using one-way wave methods.
Wave propagation and imaging in wavelet domain: Wavelet-Beamlet migration.
Seismic wave propagation in inhomogeneous media (including teleseismic, regional and local phases).
Modeling and synthetics in elastic media and elasto-acoustic media.
Stochastic treatment of seismic waves in complex media modeled as random media. Large array seismology and source discrimination.
Tomography, holography, migration and wave field imaging and inversion, including Q-tomography and the newly developed stochastic tomography.
Seismic wave scattering and attenuation. Separation of the scattering attenuation from the intrinsic attenuation.
Lithospheric inhomogeneities revealed from seismic wave scattering.
Coda wave study and earthquake monitoring & prediction.