Department of Earth and Planetary Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.
Science. 2011 Jun 17;332(6036):1426-9. doi: 10.1126/science.1207020. Epub 2011 May 19.
Strong spatial variation of rupture characteristics in the moment magnitude (M(w)) 9.0 Tohoku-Oki megathrust earthquake controlled both the strength of shaking and the size of the tsunami that followed. Finite-source imaging reveals that the rupture consisted of a small initial phase, deep rupture for up to 40 seconds, extensive shallow rupture at 60 to 70 seconds, and continuing deep rupture lasting more than 100 seconds. A combination of a shallow dipping fault and a compliant hanging wall may have enabled large shallow slip near the trench. Normal faulting aftershocks in the area of high slip suggest dynamic overshoot on the fault. Despite prodigious total slip, shallower parts of the rupture weakly radiated at high frequencies, whereas deeper parts of the rupture radiated strongly at high frequencies.
在矩震级（Mw）9.0 的东日本大地震中，断裂特征的强烈空间变化既控制了震动的强度，也控制了随后海啸的规模。有限源成象显示，这次破裂由一个小的初始阶段、长达 40 秒的深破裂、60 至 70 秒的广泛浅层破裂以及持续 100 多秒的深破裂组成。浅倾斜断层和柔软的上盘的组合可能使沟槽附近出现了大量浅层滑动。在高滑动区发生的正断层余震表明断层上存在超动态。尽管总滑动量巨大，但破裂的浅层部分在高频下辐射较弱，而破裂的深层部分在高频下则强烈辐射。
