Synthesizing High-Frequency (1-25 HZ) Regional Phases at Large Distances (1000 KM) Using Generalized Screen Propagators (GSP)

Based on the half-space screen propagator developed in our previous project, we successfully extended the method to the case of irregular surface topography by the conformal and non-conformal topographic transforms. Its validity and potential applications have been numerically demonstrated by compar...

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Bibliographic Details
Main Authors: Wu, Ru-Shan, Xie, Xiao-Bi, Wu, Xianyun
Format: Report
Language:English
Subjects:
BOUNDARY ELEMENT METHODS
FINITE DIFFERENCE THEORY
GENERALIZED SCREEN METHOD
HIGH FREQUENCY
LG-WAVE
LONG RANGE(DISTANCE)
NUMERICAL ANALYSIS
Numerical Mathematics
Optics
PE4662
PLANE WAVES
RAYLEIGH WAVES
SEISMIC WAVE PROPAGATION
SEISMIC WAVES
SURFACE WAVES
Theoretical Mathematics
WAVE PROPAGATION
WUAFRLPRABKBDH64117
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Summary:Based on the half-space screen propagator developed in our previous project, we successfully extended the method to the case of irregular surface topography by the conformal and non-conformal topographic transforms. Its validity and potential applications have been numerically demonstrated by comparing with the boundary element method. The new method can handle combined effects of small-scale heterogeneities (random media) and rough random topography on Lg wave propagation. It is also 2-3 orders of magnitude faster than the finite difference method. In the P-SV wave case, reflected plane waves from a free surface are incorporated into the elastic screen method for Lg wave simulation. Due to the presence of a surface wave (Rayleigh wave), both the real and imaginary pans of the wavenumber must be included. Body waves including reflected and convened waves are calculated using real wavenumber integration; surface wave are calculated with imaginary wavenumber integration. The comparison between results from numerical test and the wavenumber integration method shows excellent agreement. Numerical results show that this is a promising method for simulating path effects in different regions for various monitoring discriminants such as Pn/L or Sn/Lg, etc. Sponsor's rept. no. DTRA-TR-OO-32.