Frequency-Dependent Characteristics of Regional Seismic Phases: Propagation of Pn in Western China
Abstract
The propagation of Pn waves has been investigated over a large region in western China using regional events recorded by the Hi-CLIMB array. Seismic attributes, including arrival times, Hilbert envelope amplitudes, and pulse frequencies, are modeled to investigate how velocity structures in the crust and the upper mantle affect the propagation of the Pn wave in Tibet. Traveltimes are first modeled using 3D ray tracing to construct a 3D velocity model beneath the Hi-CLIMB array. The spectral element method, which provides complete numerical wave solutions in laterally varying media, was then used to model the seismic attribute data. Velocity and attenuation models beneath the Hi-CLIMB array are constructed and trade-offs between structural effects and attenuation are investigated. The objective of the study was to obtain self-consistent models of Pn propagation in western China free from assumptions such as a frequency-independent geometric spreading. To this end, our results should advance efforts in isolating effects of frequency-dependent propagation from those of pure-inelastic attenuation (Q), leading to improved methodologies for discrimination and yield estimates at regional distances.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 31, 2011
- Accession Number
- ADA540679
Entities
People
- Robert L. Nowack
- Wang-ping Chen
Organizations
- Purdue University