1992年四川力马地震序列期间激发的孕震结构

对小震序列的深入研究或许可以作为对大震序列震后趋势研究的替代，本文将地震模拟量已转化为数字记录的马力小震序列来尝试这种替代。。

Earthquake-Generating Structure during the Period of the 1992 Sichuan Lima Earthquake Sequence

In this paper, a test or alternative scheme researching small earthquake sequences for large earthquake sequences is suggested, a small earthquake sequence-Lima earthquake sequece of which modelling observed records have been turned into digital data is made use of this test. In order to provide the deep construction background and the spatial distribution of structure for generating earthquake, the p-wave and S-wave layered velocity models in this area are obtained by using mine explosion and earthquake observed records; then, the hypocenter locations and focal depths of Lima earthquake sequence are determined adopting the velocity models given above and using a location method with well numerical property for a microseismic monitoring network (Zhao, Z. , et al, 1994) and a new method for determining focal depth from data of a local seismographic network (Zhao, Z., 1992) ; finally, on this bases, the variation of quality factor Q of crustal medium during the period of the sequence is estimated.The obtained results show: the trend of spacial hypocenter distribution in Lima earthquake sequence as seen from the three-dimensional perspective graph is corresponding with the strikes of local active faulted zones; the focal depths of this sequence from shallow to deep until close to the lower crust; these condary mainshock appears at another faulted zone near by the faulted zone where the first mainshock occurred;during this sequence development, the quality factors reduce to a lower value than the average Q of this area. Thus, we suggest that when assessing the trend analysis of aftershock, we should trace the variances of some characteristic parameters, at the same time, we should take the regional conditions and tectonic characters into account.