Multimodal Rayleigh and Love wave joint inversion for S-wave velocity structures in Kanto Basin, Japan
Multimodal Rayleigh and Love wave joint inversion for S-wave velocity structures in Kanto Basin, Japan
复制标题
日本关东盆地横波速度结构的多模态瑞利波和勒夫波联合反演
DOI：
10.1029/2022jb025017
复制
发表时间：
2023
期刊：
影响因子：
--
通讯作者：
T. Tsuji
中科院分区：
文献类型：
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作者：
H. Nimiya;T. Ikeda;T. Tsuji
在日本人口稠密的关东盆地，由于存在厚厚的沉积物，放大了强烈的地面运动，因此预防地震灾害至关重要。为此，高分辨率的三维S波速度模型对于理解强地面运动的复杂放大至关重要。利用Rayleigh波和Love波多峰频散曲线的联合反演建立了三维横波速度模型。与仅使用基本模式相比，包含更高模式显著提高了面波反演的准确性和精度超过50%。我们提出的模型揭示了向东的沉积物的低速异常和基底岩石的弯曲速度轮廓，从而更好地解释了在过去的均匀多层模型中无法解释的观察到的复杂表面波频散曲线。估计的S波速度模型更好地反映了地下非均匀性，为预计发生大地震的大都市地区的灾害评估提供了重要信息。
Prevention of earthquake disaster is critical in the densely populated Kanto Basin, Japan, because of the presence of thick sediments that amplify strong ground motion. For this, a high‐resolution three‐dimensional S‐wave velocity model is essential to understand the complex amplification of strong ground motion. We constructed a three‐dimensional S‐wave velocity model using the joint inversion of multimodal dispersion curves of Rayleigh and Love waves. Inclusion of higher modes significantly improved the accuracy and precision of the surface‐wave inversion by more than 50% compared to using only fundamental mode. Our proposed model revealed a low‐velocity anomaly of sediments toward the east and a curved velocity contour of the basement rock, thereby better explaining the observed complex surface‐wave dispersion curves that have been unexplained in past homogeneous multilayered models. Estimated S‐wave velocity model better reflected subsurface heterogeneity, providing vital information for hazard assessment in a metropolitan area where huge earthquakes are expected.