Hsu Ya-Ju, Simons Mark, Avouac Jean-Philippe, Galetzka John, Sieh Kerry, Chlieh Mohamed, Natawidjaja Danny, Prawirodirdjo Linette, Bock Yehuda
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
Science. 2006 Jun 30;312(5782):1921-6. doi: 10.1126/science.1126960.
Continuously recording Global Positioning System stations near the 28 March 2005 rupture of the Sunda megathrust [moment magnitude (Mw) 8.7] show that the earthquake triggered aseismic frictional afterslip on the subduction megathrust, with a major fraction of this slip in the up-dip direction from the main rupture. Eleven months after the main shock, afterslip continues at rates several times the average interseismic rate, resulting in deformation equivalent to at least a M(w) 8.2 earthquake. In general, along-strike variations in frictional behavior appear to persist over multiple earthquake cycles. Aftershocks cluster along the boundary between the region of coseismic slip and the up-dip creeping zone. We observe that the cumulative number of aftershocks increases linearly with postseismic displacements; this finding suggests that the temporal evolution of aftershocks is governed by afterslip.
2005年3月28日苏门答腊巨型逆冲断层发生矩震级（Mw）8.7地震，附近连续记录的全球定位系统（GPS）台站显示，此次地震触发了俯冲巨型逆冲断层上的无震摩擦余滑，其中大部分余滑发生在主破裂上倾方向。主震发生11个月后，余滑仍以比平均震间期速率快几倍的速度持续，导致的形变量至少相当于一次Mw8.2级地震。总体而言，摩擦行为的走向变化似乎在多个地震周期中持续存在。余震沿同震滑动区域和上倾蠕动带之间的边界聚集。我们观察到余震累积数量随震后位移呈线性增加；这一发现表明余震的时间演化受余滑控制。
