Three‐dimensional finite difference simulation of long‐period ground motions for the 2003 Tokachi‐oki, Japan, earthquake
Three‐dimensional finite difference simulation of long‐period ground motions for the 2003 Tokachi‐oki, Japan, earthquake
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DOI：
10.1029/2007jb005452
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发表时间：
2008-07
影响因子：
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通讯作者：
S. Aoi;R. Honda;N. Morikawa;H. Sekiguchi;Haruhiko Suzuki;Y. Hayakawa;T. Kunugi;H. Fujiwara
中科院分区：
文献类型：
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作者：
S. Aoi;R. Honda;N. Morikawa;H. Sekiguchi;Haruhiko Suzuki;Y. Hayakawa;T. Kunugi;H. Fujiwara
[1]为了探讨长周期地震动的产生和传播机制，我们使用了三维有限差分法模拟波传播在2003年Mw 8.3 Tokachi-oki，日本，地震。一个大规模的计算与反演滑动模型和地质和地震学为基础的速度结构模型成功地再现了大量观察到的速度地震图的整体特征为3.3至25秒的周期范围。在Yufutsu盆地观察到持续时间延长的显著长周期地面运动，Tomakomai的油罐由于与地面运动相关的晃动而受损。我们的模拟结果显示，大地震和浅地震的组合和沉积盆地的深度产生了长周期的地面运动，持续时间为几百秒。与从西向东加深的整个盆地的几何形状形成对比的是，Yufutsu盆地包含一个从东向西加深的内部次盆地。长周期地震动在盆地东部和西部都得到了放大，西部的持续时间大大延长。一系列的计算，有和没有每个速度层内的盆地表明，盆地响应放大长周期地面运动的预期和子盆地响应是有效的放大和延长长周期地面运动。我们的定量三维有限差分模拟澄清了2003年十胜冲地震期间发生在汤伏盆地的灾难性长周期地面运动的产生。
[1] To explore the generation and propagation mechanisms of long-period ground motions, we used a 3-D finite difference method to simulate wave propagation during the 2003 Mw 8.3 Tokachi-oki, Japan, earthquake. A large-scale computation with an inverted slip model and a geological- and geophysical-based velocity structure model successfully reproduced the overall characteristics of substantial observed velocity seismograms for a period range of 3.3 to 25 s. Significant long-period ground motions of extended duration were observed in the Yufutsu basin, where oil tanks were damaged at Tomakomai because of sloshing associated with the ground motions. Our simulation revealed that the combination of the large and shallow earthquake and the deep extent of the sedimentary basin generated long-period ground motions with a duration of several hundred seconds. The Yufutsu basin contains an internal subbasin that deepens from east to west, in contrast with the geometry of the overall basin that deepens from west to east. The long-period ground motions were amplified in both the eastern and western parts of the basin, with the durations being greatly extended in the western part. A series of computations with and without each of the velocity layers within the basin demonstrated that the basin response amplifies long-period ground motions as expected and that the subbasin response is effective in amplifying and extending long-period ground motions. Our quantitative 3-D finite difference simulations clarify the generation of disastrous long-period ground motions that occurred in the Yufutsu basin during the 2003 Tokachi-oki earthquake.