Scaling of earthquake rupture growth in the Parkfield area: Self‐similar growth and suppression by the finite seismogenic layer
Scaling of earthquake rupture growth in the Parkfield area: Self‐similar growth and suppression by the finite seismogenic layer
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DOI：
10.1029/2009jb007122
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发表时间：
2010-11
影响因子：
--
通讯作者：
T. Uchide;S. Ide
中科院分区：
文献类型：
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作者：
T. Uchide;S. Ide
我们提出了一个新的地震破裂增长时程尺度框架，并对加州帕克菲尔德（Parkfield）大震级范围（Mw 1.7-6.0）地震的矩率和累积矩函数进行了尺度化。利用经验格林函数技术，推导了1.7 ~ 4.6级中小地震的矩率和累积矩函数。除6.0 Mw地震外，各地震的矩率函数基本一致，在前半段（增长阶段）迅速增加，后半段（下降阶段）减速。在生长阶段，累积矩函数近似为Mo (t) [Nm] = 2 × 1017 (t [s])3，与最终地震大小无关。累积力矩与时间立方的比例关系意味着地震破裂增长过程中的自相似性。在下降阶段，累积弯矩函数偏离共同破裂曲线。Mw 6.0事件也沿着同一破裂曲线增长，直到1 s，之后的累积矩函数与发生时间成正比。这是因为有限的发震层限制了动力破裂的垂直程度。我们的方法和结果有助于我们对震源物理的理解，特别是对地震破裂生长过程的理解，这可能有助于改进地震预警技术。
[1] We propose a new framework on the scaling of earthquake rupture growth time history, and we scale the moment rate and the cumulative moment functions of earthquakes over a wide magnitude range (Mw 1.7–6.0) in Parkfield, California. The moment rate and the cumulative moment functions of the small and medium earthquakes (Mw 1.7–4.6) are derived by slip inversion analyses with the empirical Green’s function technique. The moment rate functions of the investigated earthquakes, except the Mw 6.0 event, are similar to each other, increasing rapidly in the first half (growth stage) and decelerating in the latter half (decline stage). In the growth stage, the cumulative moment functions are approximated by Mo (t) [Nm] = 2 × 1017 (t [s])3 independent of the final size of the earthquakes. The proportionality of the cumulative moment to the cube of time implies self-similarity during earthquake rupture growth. In the decline stage, the cumulative moment function veers off the common rupture curve. The Mw 6.0 event also grows along the same rupture curve until 1 s, after which the cumulative moment function is proportional to time from the onset itself. This is because the finite seismogenic layer limits the vertical extent of dynamic rupture. Our method and results contribute to our understanding of earthquake source physics, especially on earthquake rupture growth processes, which may help to improve earthquake early warning techniques.