Propagation of Regional Phases and Their Codas in Southern Asia and the Middle East
Abstract
Observed velocities and attenuation of fundamental-mode Rayleigh waves in the period range 7-82 sec were inverted for shear-wave velocity and shear-wave Q structure in the Middle East using a two-station method. Additional information on Q structure variation within each region was obtained by studying amplitude spectra of fundamental-mode and higher-mode Rayleigh waves. We obtained models for the Turkish and Iranian Plateaus (Region 1), areas surrounding and including the Black and Caspian - Seas (Region 2), and the Arabian Peninsula (Region 3). The effect of continent-ocean boundaries and mixed paths in Region 2 may lead to unrealistic features in the models obtained there. Shear velocities vary significantly in the uppermost 10 km of the crust, being 3.21, 2.85, and 3.39 km/s for Regions 1, 2, and 3, respectively. Q's for the upper 10 km of the crust are 63, 71, and 201 for Regions 1, 2, and 3, respectively. Crustal Q's at 30 km depth for the three regions are about 51, 71, and 134. The lower crustal Q values contrast sharply with results from stable continental regions where shear-wave Q may be as high as a thousand or more.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 17, 1997
- Accession Number
- ADA345543
Entities
People
- Brian J. Mitchell
- Lianli Cong
Organizations
- Saint Louis University