断层滑动速率、地震重复时间和平均应力降
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摘要
本文综述了国内外大地震复发间隔研究的现状，系统整理了中国大陆活断层滑动速率，已发现的古地震遣迹及古地震复发间隔。结果表明，在滑动速率较大的活断层发现的古地震复发间隔较短．Ｋａｎａｍｏｒｉ和Ａｌｌｅｎ（１９８５）研究了具有大范围重复时间（２０年到几千年）的板内大地震的震源参数，发现复发间隔较长的大地震具有较高的平均应力降。我们在实验室内研究了应变速率不同时固体围压三轴压缩下完整花岗岩破裂后的粘滑现象。结果表明，粘滑事件的复发间隔受应变速率控制，复发间隔随应变速率升高而减小。粘滑事件在时间上的分布组合方式呈现多样化变化，基本上可分为三种模式：单发式，复发式，群发式。当应变速率较低时，应变速率对应力降的影响较小，当应变速率升高到一定值时，粘滑应力降骤减。在应变速率较低的实验中主破裂发育成两条共轭破裂，随应变速率升高，主破裂逐渐转化为单一破裂。也就是说，当样品的主破裂形成两条共扼破裂时，粘滑应力降较高，而样品的主破裂呈现单一破裂面时，粘滑应力降较低。应力降与粘滑复发间隔的关系较复杂。本文的实验发现，应变速率是影响粘滑复发间隔，应力降以及主破裂的几何分布，破裂面的粗糙程度的关键因素。本文的实验结果对认识天然地震的复发?
In this paper, the Holocene active fault slip rate, relic locations and recurrence intervals of paleoearthquakes in China continent were systemized. The results show that active faults with large slip rate characterizes shorter paleoearthquake recurrence intervals and the average stress drop. The friction slip after the intact granite fracturing under solid confining medium triaxial pressure were studied in this paper. The results show that the increasing of strain rate the mode of temporal distribution and the recurrence intervals are quite diverse.There are three modes of recurrence: single mode, clustering mode and mixed mode.When strain rate is lower, strain rate produce a weak impact on the stress drop, but there a more rapid decrease in stress drop with the increasing of strain rate. With increasing strain rate, the main fracture developed into a single fracture. The stress drop of stick slip events seem corresponding to the geometry patterns of main fracture. When the main fracture appears as two conjugate fractures, the stress drop is higher. When the main fracture appears as a single fracture, the stress drop is lower. There is only a weak relation between stress drops and recurrence intervals of stick slip events.We can conclude that the strain rate produce a great impact on stress and recurrence intervals of stick slip events and roughness and patterns of rock samples.
In this paper, the Holocene active fault slip rate, relic locations and recurrence intervals of paleoearthquakes in China continent were systemized. The results show that active faults with large slip rate characterizes shorter paleoearthquake recurrence intervals and the average stress drop. The friction slip after the intact granite fracturing under solid confining medium triaxial pressure were studied in this paper. The results show that the increasing of strain rate the mode of temporal distribution and the recurrence intervals are quite diverse.There are three modes of recurrence: single mode, clustering mode and mixed mode.When strain rate is lower, strain rate produce a weak impact on the stress drop, but there a more rapid decrease in stress drop with the increasing of strain rate. With increasing strain rate, the main fracture developed into a single fracture. The stress drop of stick slip events seem corresponding to the geometry patterns of main fracture. When the main fracture appears as two conjugate fractures, the stress drop is higher. When the main fracture appears as a single fracture, the stress drop is lower. There is only a weak relation between stress drops and recurrence intervals of stick slip events.We can conclude that the strain rate produce a great impact on stress and recurrence intervals of stick slip events and roughness and patterns of rock samples.
引文
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