Along-trench variation in seafloor displacements after the 2011 Tohoku earthquake.
Along-trench variation in seafloor displacements after the 2011 Tohoku earthquake.
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DOI：
10.1126/sciadv.1700113
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发表时间：
2017-07
期刊：
影响因子：
13.6
通讯作者：
Hino R
中科院分区：
文献类型：
--
作者：
Tomita F;Kido M;Ohta Y;Iinuma T;Hino R
东北地震后观测到的海底位移对评估变形过程有很大的限制。2011年东北冲地震是在其震源区域及其周围使用海底大地测量技术观测到的最大地震。与同震破裂和震后快速变形有关的大的地壳变形已经被报道。然而，这些观测结果不足以描述发生在大破裂区周围的震后变形过程。我们报告了海底全球定位系统和声学测距（GPS-A）观测的第一个结果，这些观测是基于使用2012年9月沿着日本海沟部署的扩展GPS-A网络进行的近4年的重复活动调查。观测到的震后位移速率（DR）显示出明显的空间变化沿着的沟槽：（i）明显的向陆DR在大的同震滑动区[主破裂区（PRA）]，证明粘弹性松弛的优势;（ii）显着的向沟DR在南部的PRA，表明快速后滑;和（iii）轻微的向沟DR在北部的PRA。这些特征不仅为建立更完整的粘弹性松弛模型提供了重要的理论依据，而且还以清晰的空间分辨率揭示沿着板块界面后滑和断层闭锁的空间变化规律，为地震危险性评价的改进提供了宝贵的信息。
Seafloor displacements observed after the Tohoku earthquake place large constraints on assessing the deformation process. The 2011 Tohoku-oki earthquake was the largest earthquake ever observed with seafloor geodetic techniques in and around its source region. Large crustal deformation associated with both the coseismic rupture and the rapid postseismic deformation has been reported. However, these observations are insufficient to describe the postseismic deformation processes occurring around the broad rupture area. We report the first results of seafloor Global Positioning System and acoustic ranging (GPS-A) observations based on repeated campaign surveys conducted over nearly 4 years using the extended GPS-A network deployed along the Japan Trench in September 2012. The observed postseismic displacement rates (DRs) show evident spatial variation along the trench: (i) distinct landward DRs in the large coseismic slip area [primary rupture area (PRA)], evidencing the predominance of viscoelastic relaxation; (ii) remarkable trenchward DRs in the south of the PRA, indicating rapid afterslip; and (iii) slight trenchward DRs in the north of the PRA. These features provide great insights into constructing a more complete model of viscoelastic relaxation, and they also indicate spatial variation of afterslip and fault locking along the plate interface with clear spatial resolution, providing invaluable information for the improvement of seismic hazard assessment.
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影响因子：
4.4
作者：
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