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从反演参数选择方式和构造意义方面分析和计算了发生在秘鲁消减带上1974年10月3日M_W8.0地震及同年11月9日的最大余震(M_S7.1)在时空上的分布。通过反演长周期世界标准地震台网的远场P和SH波取得了破裂历史。我们要说明,对于一个足够复杂的震源,它的滑动幅度、上升时间和破裂时间都随空间变化。如果选用了没考虑这些复杂性的参数,就会得出错误的结果。这种反演方法采用了可以离散的上升时间和破裂时间的断层参数。在地方台站上记录到的定位好的余震,具有和远场确定的震源同样的辐射图象,这有助于约束消减带的几何形状。对于主震,最好是用一个复合断层,由倾角为11°的较浅的断层和倾角为30°较深的断层链接而成。认为最可取的成核深度为11～15km之间。破裂为双侧破裂,具有两个主要滑动集中区,第一个在震中西北60～70km,第二个在震中西南80～100km。对于这些震源区,上升时间在6～18s之间。我们估计的上升时间与破裂穿过主要凹凸体的时间是一致的。11月9日余震的滑动分布落在主震震源附近其破裂图案中一个明显的空区。11月9日事件具有简单的上升时间函数,持续时间为2s。地方台网记录到的余震集中分布在即将发生的11月9日事件的附近,在最大主震源区向下倾斜的位置,主震期间的滑动集中在浅于15km的地方,从震源上倾方向扩展到海沟轴板块边界附近,大量浅部滑动归因于缺乏沉积物显著的沉积楔以及俯冲板块相对年轻的年龄和很高的汇聚速度,这导致了海沟轴附近很好的地震耦合。
The temporal and spatial distribution of the M_W8.0 earthquake on October 3, 1974 and the M_S7.1 of November 9, the same year, on the Peruvian decay zone were analyzed and calculated from the aspects of inversion parameter selection and tectonic significance. The rupture history was obtained by inverting the far-field P and SH waves of the long-period world standard seismic network. We will show that for a sufficiently complex source, its magnitude of slip, rise time, and rupture time vary with space. If you choose the parameters without considering these complexities, you will get the wrong result. This inversion method uses fault parameters that can be discrete ascending time and rupture time. The well-located aftershocks recorded at local stations have the same radiation image as the hypocenter identified by the far field, which helps to constrain the geometry of the abatement zone. For a mainshock, it is best to use a composite fault that consists of a shallow fault with a dip of 11 ° and a fault with a dip of 30 °. The most desirable nucleation depth is considered to be between 11 and 15 km. The rupture is a bilateral rupture with two major slip zones, the first one 60 to 70 km northwest of the epicenter and the second 80 to 100 km southwest of the epicenter. For these source regions, the rise time is between 6 ~ 18s. Our estimated rise time is consistent with the time it takes to rupture through the main asperities. The slip distribution of aftershocks on Nov. 9 landed in a clear empty area in the rupture pattern near the mainshock source. November 9 events have a simple rise time function for 2 seconds. The aftershocks recorded by the local stations are concentrated in the vicinity of the upcoming event on November 9, and are inclined downward in the direction of the largest mainshock source. The slips during the main shock are concentrated at shallow places of more than 15 km, Extending into the vicinity of the trench axis, the bulk of the shallow slip is attributed to the lack of significant sediment wedges in the sediments and the relatively young age and high convergence velocity of the subducted slabs, resulting in good seismic coupling near the trench axis.