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6月28日大贝尔地震发生于15:05:21格林尼治((GMT))。该地震被认为是早些时间M_w=7.3的兰德斯地震的余震。从所有余震的位置和长周期震源研究看,一般认为破裂是向北东方向传播的。然而,地表没有发现破裂,由强震和TERRAscope数据所确定的主震位置相互一致,并且没有位于假设的断层面上。此外,对TERRAscope台阵中得到的记录进行的方向性分析表明,显著的短周期和长周期能量沿假定的相对断层面向北西方向传播,沿假定的破裂面和北西方向的相对断层面分布大量早期余震支持了这一观测结果。1992年6月28日14:43(GMT)、M_w=5.2前震与1992年8月17日、M_w=5.0余震的经验格林函数处理所得到的结果相互一致,它表明大贝尔地震至少由两个主要的子震组成。从经验格林函数的结果中我们推导出,第二次和可能的第三次次级子震发生在假定的(北东走向)主震破裂面上。但是,显著的地震矩释放发生在相对北西走向上。我们提供了大贝尔主震宽频位移记录的线状震源断层模型,它表明必须是双断层地震才能产生出所观测到的波形。主震的位置及定向性分析施加的限制要求初始破裂向着北西方向,走向为320°,大约4 s之后,沿北东.南西方向断层(北偏东50°)有一双向破裂。
June 28 Big Bell Earthquake took place at 15:05:21 GMT (GMT). The earthquake was considered aftershock of the Landers earthquake with M_w = 7.3 earlier. From all aftershock locations and long-period hypocenter studies, it is generally believed that rupture is propagating to the NE direction. However, no rupture was observed on the surface, and the main shocks determined by strong earthquakes and TERRAscope data were consistent with each other and were not located on the hypothetical fault plane. In addition, the directional analysis of the records obtained from the TERRAscope array shows that significant short-period and long-period energies propagate northwest along the assumed relative fault plane and a large number of early phases distribute along the hypothetical and northwesterly relative fault planes Aftershocks support this observation. The result obtained from empirical Green’s function processing of the 14th June 1992 (GMT), M_w = 5.2 foreshock and M_w = 5.0 aftershocks on August 17, 1992 is in agreement with each other, indicating that the Dabeel Earthquake consists of at least two The main sub-earthquake composition. From the results of empirical Green’s function, we deduce that the second and possible third sub-sub-earthquakes occur on the assumed (northeastward) mantle rupture plane. However, significant moment release occurs on a relative northwestward strike. We provide a linear hypocenter fault model for large Belle mainshock broadband displacement records that indicates that a double-fault earthquake must occur to produce the observed waveform. The constraints imposed by the analysis of the location and orientation of the main shock require that the initial rupture be headed northwest and strike at 320 °. After about 4 s, there is a bi-directional rupture along the NE-NNW strike (50 ° north east).