TY - JOUR

T1 - Effect of 2-D topography on the 3-D seismic wavefield using a 2.5-D discrete wavenumber-boundary integral equation method

AU - Takenaka, H.

AU - Kennett, B. L.N.

AU - Fujiwara, H.

PY - 1996/3

Y1 - 1996/3

N2 - A full treatment of topographic effects on the seismic wavefield requires a 3-D treatment of the topography and a 3-D calculation for the wavefield. However, such full 3-D calculations are still very expensive to perform. An economical approach, which does not require the same level of computational resources as full 3-D modelling, is to examine the 3-D response of a model in which the heterogeneity pattern is 2-D (the so-called 2.5-D problem). Such 2.5-D methods can calculate 3-D wavefields without huge computer memory requirements, since they require storage nearly equal to that of the corresponding 2-D calculations. In this paper, we consider wave propagation from a point source in the presence of 2-D irregular topography, and develop a computational method for such 2.5-D wavepropagation problems. This approach is an extension to the 2.5-D case of the discrete wavenumber-boundary integral equation method introduced by Bouchon (1985) and Gaffet & Bouchon (1989) to study 2-D topographic problems. One of the most significant advantages of the 2.5-D calculations is that calculations are performed for a point source and so it is possible for us to take into account the 3-D radiation pattern from the source. We demonstrate that this discrete wavenumber-boundary integral equation procedure, coupled with a Green's function decomposition into P-and S-wave contributions, provides a flexible and effective means of evaluating the wavefield.

AB - A full treatment of topographic effects on the seismic wavefield requires a 3-D treatment of the topography and a 3-D calculation for the wavefield. However, such full 3-D calculations are still very expensive to perform. An economical approach, which does not require the same level of computational resources as full 3-D modelling, is to examine the 3-D response of a model in which the heterogeneity pattern is 2-D (the so-called 2.5-D problem). Such 2.5-D methods can calculate 3-D wavefields without huge computer memory requirements, since they require storage nearly equal to that of the corresponding 2-D calculations. In this paper, we consider wave propagation from a point source in the presence of 2-D irregular topography, and develop a computational method for such 2.5-D wavepropagation problems. This approach is an extension to the 2.5-D case of the discrete wavenumber-boundary integral equation method introduced by Bouchon (1985) and Gaffet & Bouchon (1989) to study 2-D topographic problems. One of the most significant advantages of the 2.5-D calculations is that calculations are performed for a point source and so it is possible for us to take into account the 3-D radiation pattern from the source. We demonstrate that this discrete wavenumber-boundary integral equation procedure, coupled with a Green's function decomposition into P-and S-wave contributions, provides a flexible and effective means of evaluating the wavefield.

KW - P waves

KW - S waves

KW - Topography

KW - Wave propagation

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U2 - 10.1111/j.1365-246X.1996.tb05635.x

DO - 10.1111/j.1365-246X.1996.tb05635.x

M3 - Article

AN - SCOPUS:0029730564

VL - 124

SP - 741

EP - 755

JO - Geophysical Journal International

JF - Geophysical Journal International

SN - 0956-540X

IS - 3

ER -