Visualization of 3D Wave Propagation from the 2000 Tottori-ken Seibu, Japan, Earthquake: Observation and Numerical Simulation
Visualization of 3D Wave Propagation from the 2000 Tottori-ken Seibu, Japan, Earthquake: Observation and Numerical Simulation
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2000 年日本鸟取县西武地震的 3D 波传播可视化：观测和数值模拟
DOI：
10.1785/0120020160
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发表时间：
2003
影响因子：
3
通讯作者：
K. Koketsu
中科院分区：
文献类型：
--
作者：
T. Furumura;B. Kennett;K. Koketsu
日本密集的强震台网(K-Net和Kik-Net)提供了一种在大地震期间直接可视化区域波传播的手段。对于2000年日本西部鸟取县西武6.6级地震，由大量台阵观测直接内插得到的地面运动快照清楚地显示了震源辐射的性质和传播到区域距离的地震波场特征。在日本西部，地震波场的大部分地区以三分量加速度记录上的高频(0.2-5 Hz)lg波为主，切向位移上以长周期(T 10秒)基模Love波为主。地壳和上地幔结构存在强烈的横向变化，如低速浅层和高速菲律宾海板块浅俯冲到地幔中，对区域波场造成了重大的改变。通过将观测结果与三维模型的数值模拟进行比较，进一步了解了地震波场的性质，其中包括嵌入亚网格的沉积盆地。使用伪谱/有限差分混合方法的多重网格并行计算允许包含2000年鸟取县西武地震震源过程的真实模型。通过日本西部复杂结构传播的区域波场的主要特征有很好的一致性。然而，观测和计算机模拟之间的差异表明有必要进一步改进源模型和结构模型。考虑了沉积盆地中人口中心的放大效应，意味着模拟过程已经适用于估计未来地震情景的主要地面运动模式。
The dense networks of strong-ground-motion instruments in Japan (K- NET and KiK-net) provide a means of direct visualization of regional wave propa- gation during large earthquakes. For the 2000 Tottori-ken Seibu earthquake (Mw 6.6) in western Japan, snapshots of ground motion, derived directly from interpolation of a large number of array observations, demonstrate clearly the nature of the source radiation and the character of the seismic wave field propagating to regional dis- tances. In western Japan the wave field from the earthquake is characterized, in most parts, by the dominance of high-frequency (0.2-5 Hz) Lg waves on three-component acceleration records and longer-period (T 10 sec) fundamental-mode Love waves in tangential displacement. The presence of strong lateral variations in the crust and upper-mantle structures, such as the low-velocity superficial layer and the high- velocity Philippine Sea plate with shallow subduction into the mantle, impose sig- nificant modifications on the regional wave field. Further insight into the nature of the seismic wave field is gained by comparison of the observations with numerical simulation for a 3D model, including sedimentary basins by an embedded submesh. A multigrid, parallel computation using a hybrid Pseudospectral/Finite Difference Method allows the inclusion of a realistic model of the source process for the 2000 Tottori-Ken Seibu earthquake. There is good agreement in the dominant features of the regional wave field propagating through the complex structure of western Japan. However, the differences between the observations and the computer simulations indicates the need for further refinement of the source and structural models. The inclusion of amplification effects for the population centers in sedimentary basins means that the modeling procedure is already suitable for estimating the main pattern of ground motion for future earthquake scenarios.