Interplate Coupling Distribution Along the Nankai Trough in Southwest Japan Estimated From the Block Motion Model Based on Onshore GNSS and Seafloor GNSS/A Observations
Interplate Coupling Distribution Along the Nankai Trough in Southwest Japan Estimated From the Block Motion Model Based on Onshore GNSS and Seafloor GNSS/A Observations
复制标题
基于陆上 GNSS 和海底 GNSS/A 观测的块体运动模型估计的日本西南部南海海槽沿线的板间耦合分布
DOI：
--
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Takeo Ito
中科院分区：
文献类型：
--
作者：
H. Kimura;K. Tadokoro;Takeo Ito
沿着日本西南部的南卡槽，大约100年的复发间隔是反复发生的耦合比的dip异质性定义为滑动缺陷率除以板收敛速率，以理解机制和/或评估未来大型大型的潜力最近，该地区的地震是海底的卫星系统声学（GNSS/A）组合技术观测网络，我们现在可以在陆上和近海地区获得地壳位移。使用海底GNSS/A和陆上GNSS数据与块运动模型沿着南卡槽沿南卡槽的耦合分布，从而最大程度地减少了空间变化对耦合估计的不确定性进行建模。 SW日本的深板界面由刚性块运动而不是对菲律宾海板俯冲板界面上的弹性响应最小化耦合估计值的建模不确定性的空间变化有助于我们估计离岸和陆上区域之间几乎均匀不确定性的耦合分布，这有助于评估板间地震和/或黄昏危害。
Along the Nankai Trough of southwest Japan, large‐magnitude interplate earthquakes (M > 8) have occurred repeatedly, with recurrence intervals of approximately 100 years. It is essential to estimate more precisely the spatial distribution of interplate coupling; that is, along‐strike and along‐dip heterogeneity of the coupling ratio defined as the slip deficit rate divided by the plate convergence rate, for understanding the mechanisms and/or assessing the potential of future mega interplate earthquakes in this region. Recently, the seafloor Global Navigation Satellite System‐Acoustic (GNSS/A) combination technique observation network has been extended, and we can now obtain crustal displacement fields for both onshore and offshore regions. In this study, we estimate interplate coupling distribution along the Nankai Trough using both seafloor GNSS/A and onshore GNSS data with the block motion model, minimizing the spatial variations of modeling uncertainties of coupling estimates. Seafloor GNSS/A data depict very strong coupling near the trough axis off of Tokai, as well as trough‐parallel heterogeneity in interplate coupling at the shallow plate interface. Using the block motion model confirmed that observed crustal deformation above the deep plate interface in SW Japan is dominated by rigid block motion rather than elastic response to slip deficit on the deep plate interface of the subducting Philippine Sea plate. The minimization of spatial variations for the modeling uncertainties of coupling estimates helps us to estimate the coupling distribution with nearly homogeneous uncertainties between offshore and onshore regions, which is useful for evaluation of interplate earthquakes and/or tsunamis hazards.