Northeast Japan is a typical island arc related to the Pacific plate subduction. The 2011 Mw9.0 Tohoku-oki earthquake provided a unique opportunity to analyze crustal deformation with different boundary conditions, similar to a gigantic rock deformation experiment. We review findings obtained through various observations and data analyses in Northeast Japan, focusing on the crustal deformation in different timescales. The occurrence of the M9 earthquake solved the ongoing paradox that the geodetic strain rate is an order of magnitude larger than the geologic estimate, showing that the centennial geodetic observation had mainly captured the elastic strain accumulation. Along the localized contraction zone along the Japan Sea coast, a comparison of postseismic and interseismic deformation patterns revealed a significant contribution of inelastic deformation, which plays an essential role in long-term deformation. Along the Pacific coast, rapid interseismic subsidence and unexpected coseismic subsidence were followed by a rapid postseismic uplift, indicating that viscous relaxation in the mantle is of essential importance. These findings advance our understanding of plate interactions and the tectonic evolution of the island arc. ▪ The 2011 Tohoku-oki earthquake provided the most complete crustal deformation data set ever for interseismic, coseismic, and postseismic periods. ▪ The discrepancy between the geologic and geodetic deformation rates in Northeast Japan is attributed to an elastic strain due to interplate locking. ▪ A significant contribution of inelastic deformation in the island arc crust is identified through a comparison of interseismic and postseismic deformations.

中文翻译：

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2011 年东北地震揭示的日本东北部岛弧的大地测量和地质变形

日本东北部是与太平洋板块俯冲有关的典型岛弧。 2011年Mw9.0 东北冲地震为分析不同边界条件下的地壳变形提供了独特的机会，类似于巨大的岩石变形实验。我们回顾了通过日本东北部的各种观测和数据分析获得的结果，重点关注不同时间尺度的地壳变形。 M9地震的发生解决了一直存在的大地应变率比地质估计大一个数量级的悖论，表明百年大地观测主要捕获了弹性应变积累。沿着日本海沿岸的局部收缩区，震后和震间变形模式的比较揭示了非弹性变形的显着贡献，它在长期变形中起着至关重要的作用。沿着太平洋海岸，快速的震间沉降和意外的同震沉降之后是快速的震后隆升，这表明地幔的粘性弛豫至关重要。这些发现增进了我们对板块相互作用和岛弧构造演化的理解。 ▪ 2011 年东北冲地震提供了迄今为止最完整的震间期、同震期和震后时期的地壳形变数据集。 ▪ 日本东北部地质和大地变形率之间的差异归因于板间锁定产生的弹性应变。 ▪ 通过比较震间和震后变形，确定了岛弧地壳非弹性变形的重要贡献。