Center for Tectonophysics, Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA.
Science. 2013 Dec 6;342(6163):1208-11. doi: 10.1126/science.1243719.
The mechanics of great subduction earthquakes are influenced by the frictional properties, structure, and composition of the plate-boundary fault. We present observations of the structure and composition of the shallow source fault of the 2011 Tohoku-Oki earthquake and tsunami from boreholes drilled by the Integrated Ocean Drilling Program Expedition 343 and 343T. Logging-while-drilling and core-sample observations show a single major plate-boundary fault accommodated the large slip of the Tohoku-Oki earthquake rupture, as well as nearly all the cumulative interplate motion at the drill site. The localization of deformation onto a limited thickness (less than 5 meters) of pelagic clay is the defining characteristic of the shallow earthquake fault, suggesting that the pelagic clay may be a regionally important control on tsunamigenic earthquakes.
大型俯冲带地震的力学特性受板块边界断层的摩擦特性、结构和组成的影响。我们从综合大洋钻探计划（IODP）第 343 号和第 343T 号考察中钻探的钻孔中，获得了 2011 年东日本大地震及其海啸的浅层震源断层的结构和组成的观测结果。随钻测井和岩芯样本观测表明，一个单一的主要板块边界断层适应了东日本大地震的大滑动，以及在钻探地点几乎所有的累积板块间运动。变形局限在一个有限的厚度（小于 5 米）的远洋粘土中，这是浅层地震断层的特征，表明远洋粘土可能是海啸地震的一个重要的区域控制因素。
