Efficient and Accurate Calculation of Ray Theory Seismic Travel Time through Variable Resolution 3D Earth Models

摘要

Realistic 3D models of the seismic velocity distribution within the Earth have the potential to significantly improve our ability to accurately and precisely locate seismic events around the world (e.g., Flanagan et al. 2007). Development of these models by tomographic inversion of observed seismic travel times and the use of such models in seismic event location calculations, require the ability to accurately and efficiently compute predicted source to receiver travel times through 3D velocity structures. Meeting these requirements on a global scale presents two fundamental challenges: 1) how to represent the 3D distribution of seismic velocity in the Earth in models that can be interpolated efficiently, and 2) how to efficiently and accurately compute predicted travel times through these models. We present a 3D variable-resolution modeling methodology and a travel time prediction algorithm based on ray theory that address these issues and are compatible with computational resources ranging from laptop computers to powerful distributed computing systems.