| 講演要旨(和文) | | 鉛直方向に任意不均質で減衰を有する媒質のτ-p(平面波)領域における弾性波動の計算を効率良く行う手法を提案する.まず,ラドン変換を用いて,鉛直方向に任意に不均質な粘弾性媒質の平面波領域における速度-応力-メモリー変数型3次元弾性波動方程式を導出し,次にそれをスタガード格子時間領域差分法(FDTD法)で解くスキームを示す.本法は,空間1次元の格子しか必要ないので,従来の2次元や3次元の差分法を用いる解法と比べてはるかに効率が良く,2次元や3次元の差分法で問題となる計算領域の側方境界からの人工反射波も無いのが特徴である. |
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| | 講演要旨(英文) | | We have derived the viscoelastic wave equations in the tau-p domain (plane-wave domain) by applying the Radon transform to the 3D viscoelastodynamic equation for 1D structures, and developed an efficient algorithm to calculate the plane-wave response of a vertically heterogeneous attenuative medium. Arbitrary Qp and Qs are incorporated into the wave equations via a general standard linear solid rheological model. A finite-difference time-domain (FDTD) staggered-grid technique is used for numerical solution of the derived plane-wave equations. The scheme uses a 1D grid, which allows for significant reduction in computation time and memory requirements compared to the corresponding 2D or 3D computations. In the proposed algorithm the domain boundaries are only at the top and bottom. The lack of artificial side reflections is another advantage of this approach. |
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