Moment tensor rate functions for the 1989 Loma Prieta Earthquake
Moment tensor rate functions for the 1989 Loma Prieta Earthquake
复制标题
1989 年洛马普列塔地震的矩张量率函数
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
B. Tichelaar
中科院分区：
文献类型：
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作者：
L. Ruff;B. Tichelaar
1989年加利福尼亚洛马普里塔地震（Ms=7.1）的断层面和整体同震滑动是我们！！（Plafker和Galloway， 1989）。Te !地震波可以用来确定力矩释放的时程。我们反演了十个宽带P波和SH波的数据集，用于最一般的点源描述：五矩张量速率函数。线性反演还提供了模型不确定性的正式估计。虽然矩张量率函数表明在破裂过程的最初几秒钟有不同的震源机制，但在95%的水平上没有统计学意义。因此，我们可以继续对单个时间函数（源时间函数）和五个标量（矩张量）进行反演。我们发现的主要的双夫妇（罢工！）从北方顺时针方向380°+ 6°，倾斜760°+5°，倾斜1200°+！0)同意Plafker和Gallo- way（1989）的结果。次要的双夫妇很少（1%）。最佳点源深度约为10公里。几个宽频P波表明，在主脉冲释放矩前几秒出现了一个小的前体。源时间函数的持续时间为9 s，力矩为2_+0.5 x1019 Nm。一次速度为2.8英磅、持续时间为9秒的双侧破裂包含了余震区。
The fault plane and overall coseismic slip of the 1989 Loma Prieta, California, earthquake (Ms=7.1) are we!! determined (Plafker and Galloway, 1989). Te!eseis- mic waves can be used to determine the time history of moment release. We invert a data set of ten broadband P and SH waves for the most general point source descrip- tion: the five moment tensor rate functions. The linear inversion also provides formal estimates of model uncer- tainty. While the moment tensor rate functions suggest a different focal mechanism for the first few seconds of the rupture process, it is not statistically significant at the 95% level. We can thus proceed to invert for one single time function (the source time function), and five scalars (the moment tensor). The major double couple that we find (strike !38o+_6 o clockwise from North, dip 76o+5 o, slip an- gle 120o+!0 o) agrees with the results of Plafker and Gallo- way (1989). The minor double couple is small (1%). The best point source depth is about 10 km. Several broadband P waves show that a small precursor occurred a few seconds before the main pulse of moment release. The duration of the source time function is 9 s, with a moment of 2_+0.5 x1019 Nm. A bilateral rupture with velocity of 2.8 ImPs and 9 s duration encompasses the aftershock region.