Full-Wave Tomographic and Moment Tensor Inversion Based on 3D Multigrid Strain Green's Tensor Databases
Abstract
A novel framework is developed to construct a 3D Earth model. This new framework results from the marriage of the multigrid method and full-wave tomography: the multigrid method is designed for numerical efficiency, while full-wave tomography is well suited for iterative update of the 3D model. It provides an efficient way to cumulatively and progressively improve the Earth model to as high resolution as observational constraints warrant. Using a new frequency-time data normalization procedure, we show that it is possible to extract up to 600-s period surface waves from ambient noise recorded by broadband seismic stations. These very broadband waves extend surface wave constraints to the crust and entire upper mantle. We collected and processed up to 23 years of continuous seismic data from broadband seismic stations in the eastern hemisphere. A full-wave ambient noise tomographic method is developed and applied to the eastern hemisphere. Three levels of finite-difference computation and inversion are carried out at the hemispherical, continental, and regional scales to progressively construct a hierarchical, multi-resolution P and S velocity model for the eastern hemisphere. The results show a much-improved resolution compared to those of conventional ambient noise tomography and earthquake tomography and provide new constraints on the geological processes in the region. Finally, we determined the moment tensors of earthquakes in southeast Tibet, using strain Green s tensors.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 30, 2014
- Accession Number
- ADA607834
Entities
People
- Yang Shen
Organizations
- University of Rhode Island