论文标题
东北奥林匹克半岛构造震颤的深度和厚度
Depth and thickness of tectonic tremor in the northeastern Olympic Peninsula
论文作者
论文摘要
构造震颤已被解释为一群低频地震，该地震位于板边界的狭窄断层上。但是，由于震颤信号中缺乏明显的冲动阶段，因此很难精确地确定震源的深度。震颤区域的厚度也不太约束。由于低频地震似乎是在狭窄的断层上，震颤可能位于狭窄的断层上，或在上海壳中的几公里宽的低剪切波速度层上分布，这被认为是一个具有高孔隙压力的区域。震颤地震图的水平和垂直成分的峰值的滞后时间，由华盛顿奥林匹克半岛的小孔径阵列记录，被解释为S减p次。使用先前研究中的震中，使用多微型反射方法从这些S减p次估计震颤深度。震颤位于不超过2-3公里的区域的板边界附近，非常接近低频地震的深度。震颤分布在更大的深度范围内，而不是低频地震。但是，由于深度的不确定性，很难得出结论震颤的来源是位于俯冲的海洋外壳的顶部，位于板块边界上方的下部大陆壳，还是在板边界处的狭窄区域。
Tectonic tremor has been explained as a swarm of low-frequency earthquakes, which are located on a narrow fault at the plate boundary. However, due to the lack of clear impulsive phases in the tremor signal, it is difficult to determine the depth of the tremor source with great precision. The thickness of the tremor region is also not well constrained. The tremor may be located on a narrow fault as the low-frequency earthquakes appear to be, or distributed over a few kilometers wide low shear-wave velocity layer in the upper oceanic crust, which is thought to be a region with high pore-fluid pressure. Lag times of peaks in the cross-correlation of the horizontal and vertical components of tremor seismograms, recorded by small-aperture arrays in the Olympic Peninsula, Washington, are interpreted to be S minus P times. Tremor depths are estimated from these S minus P times using epicenters from a previous study using a multibeam backprojection method. The tremor is located close to the plate boundary in a region no more than 2-3 kilometers thick and is very close to the depths of low-frequency earthquakes. The tremor is distributed over a wider depth range than the low-frequency earthquakes. However, due to the uncertainty on the depth, it is difficult to conclude whether the source of the tremor is located at the top of the subducting oceanic crust, in the lower continental crust just above the plate boundary, or in a narrow zone at the plate boundary.
