Interplate coupling in the Tohoku district, Japan, deduced from geodetic data inversion
Interplate coupling in the Tohoku district, Japan, deduced from geodetic data inversion
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大地测量数据反演日本东北地区板间耦合
DOI：
10.1029/1999jb900202
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发表时间：
1999
影响因子：
--
通讯作者：
T. Kato
中科院分区：
文献类型：
--
作者：
G. El;T. Kato
通过大地测量数据反演分析，研究了日本东北地区俯冲太平洋板块与上覆大陆板块之间板间耦合强度的空间分布和时间变化。用于此分析的大地测量数据是垂直（1966-1995）和水平（1979-1991）位移率，这可能代表地震间期的平均地壳运动。我们将后滑分布的平滑约束纳入观测数据中。约束的程度由超参数控制，超参数的最佳值是通过最小化赤池贝叶斯信息准则（ABIC）来确定的。在ABIC的假设下，我们可以获得唯一的解决方案。反演分析结果表明，存在两个高耦合区，一是在北边（40.5°N）20~45 km处延伸，二是在南边（38.5°N）25~55 km处延伸。北部地区平均回滑率达到55±11 mm yr−1，南部地区平均回滑率达到41±14 mm yr−1。反演分析表明，日本海沟板块辐合方向北部地区为N71°±3°W，南部地区为N48°±5°W。板间耦合朝着较浅和较深的部分变得较弱，并且表现出显着的时间变化。
The spatial distribution and the temporal change of the strength of interplate coupling between the subducting Pacific plate and overlying continental plate in the Tohoku district, northeast Japan, have been investigated through the inversion analysis of geodetic data. The geodetic data used for this analysis are the rates of vertical (1966–1995) and horizontal (1979–1991) displacements, which presumably represent average crustal movements during the interseismic period. We incorporate smoothing constraints on back slip distribution into the observed data. The degree of the constraints is controlled by hyperparameters whose optimal values are determined by minimizing Akaike's Bayesian Information Criterion (ABIC). Under the assumption of ABIC, we can obtain a unique solution. The result of the inversion analysis shows that there are two regions of high coupling, the first extending from 20 to 45 km in the north (40.5°N) and the second extending from 25 to 55 km in the south (38.5°N). The average back slip rate in the northern region reaches 55±11 mm yr−1 and in the southern region 41±14 mm yr−1. Also, the inversion analysis shows that the direction of the plate convergence at the Japan trench is N71°±3°W in the northern region and N48°±5°W in the southern region. The interplate coupling becomes weaker toward the shallower and deeper portions and exhibits significant temporal variation.