论文部分内容阅读
最近几年,一些消减带内的俯冲大地震再次破裂了以前巨大地震曾破裂过的板块边界地段引人注目。有关破裂了板块边界同一部位的相继发生的两次大地震的已有地震资料,提供了比较这两次地震的地震矩释放空间分布的机会。本文对发生在板块边界地段的地震作了此种比较,这些地段曾在下列地震中遭到破坏:(1)1957年(M_W=8.6),1986年(M_w=8.0)和1996年(M_W=7.9)的阿留申群岛地震;(2)1963年(M_W=8.5)和1995年(M_W=7.9)的千岛群岛地震;(3)1971年(M_W=8.0)和1995年(M_W=7.7)的所罗门群岛地震;(4)1968年(M_W=8.2)和1994年(M_W=7.7)的本州北部地震。以前的研究已经确定了4次初发大地震和2次复发大地震的矩释放的空间分布。这里,运用长周期面波和宽频带体波的经验格林函数分析得到的震源时间函数,反演确定了最近3次地震的滑动分布。通过比较相继地震破裂矩释放的空间分布,发现断层重复滑动图象有很大差异。1994年本州北部地震和1995年所罗门群岛地震,基本上填充了以前地震遗留下来的没有滑动的地区,而不是同一凹凸体的重新破裂。1995年千岛群岛地震和1996年阿留申群岛地震重新破裂了先前地震确定的凹凸体分布地段,但具有不同的滑动量。本研究提供了环太平洋板块边界的大震的复发性质比主要凹凸体的重复破裂更为复杂的第一个直接的证据,无论是从整个断层分段上发生的破裂是通过重复发生的具有接近相同的破裂长度、破裂地点及滑动大小的事件来实现的这一点来说,还是从各个凹凸体在后续的地震循环中以相同的滑动函数发生破裂这一点来说,所研究的4个板块边界的断层滑动都不支持特征地震式的滑动模型。这些连续发生的滑动的图象与滑动复杂性仅取决于不变的几何和构造的非均匀性的物理模型不符,而表明考虑动力学同样是重要的。
In recent years, some subduction earthquakes within the abatement zone once again broke the attention of lots of plate boundaries that had been ruptured by previous huge earthquakes. The available seismic data on two successive earthquakes that have ruptured the same part of the plate boundary provide an opportunity to compare the spatial distribution of seismic moment release for these two earthquakes. This comparison of earthquakes that occur at the boundaries of the plate boundary has been disrupted in the following earthquakes: (1) 1957 (M_w = 8.6), 1986 (M_w = 8.0) and 1996 (M_W = 7.9); (2) the Kuril Islands earthquake in 1963 (M_W = 8.5) and 1995 (M_W = 7.9); (3) the 1971 (M_W = 8.0) and 1995 (M_W = 7.7) Solomon Islands earthquake; (4) Northern Honshu Earthquake in 1968 (M_W = 8.2) and 1994 (M_W = 7.7). Previous studies have determined the spatial distribution of moment release for four initial large earthquakes and two large earthquakes. Here, the source time function obtained from empirical Green’s function analysis of long-period and broad-band body waves is used to inversely determine the slip distribution of the last three earthquakes. By comparing the spatial distribution of successive rupture moments, it is found that there is a great difference between the repeated slide images of faults. The Northern Honshu earthquake in 1994 and the Solomon Islands earthquake in 1995 basically filled the non-slip areas left over from the previous earthquakes instead of the new rupture of the same asperity. The 1995 Kuril Islands and 1996 Aleutian Islands earthquakes have again ruptured the asteroid distribution lots determined by previous earthquakes but with different slip volumes. The present study provides the first direct evidence that the recurrent nature of large earthquakes at the Pacific Rim boundary is more complex than the repeated rupture of major asperities, whether the rupture that occurs from the entire fault segment occurs through repeated occurrences with close The same rupture length, rupture location, and slip-size event, or from the point that each of the asperities fractured with the same sliding function in the subsequent seismic cycle, the four plate boundaries studied Of the fault slips do not support the characteristic earthquake-based sliding model. It is equally important to consider the kinetics of these continuously occurring sliding images that are inconsistent with the physical model whose sliding complexity depends only on the invariant geometry and the structural inhomogeneity.