2010年4月14日玉树MS7.1地震对余震的触发研究

The static stress triggering influence of the Yushu MS7.1 earthquake

摘要:

研究了2010年4月14日青海玉树7.1级地震产生的静态库仑破裂应力变化对余震及区域地震活动空间分布的影响。在考虑震源区附近区域构造应力场的基础上,由震源区构造应力和主震破裂产生的应力叠加,计算得到最容易破裂的余震断层面,进而计算玉树主震在上述余震断层面上产生的库仑破裂静态应力变化。结果表明,库仑应力变化图像与余震分布较为吻合,说明玉树主震对大部分余震有触发作用。利用相同方法计算了玉树主震对周边更大范围内地震的应力触发影响,发现大部分区域地震活动空间分布与库仑应力变化图像基本一致,中小地震大多发生在正向触发区域,但量值较小。对余震断层面与主震完全一致的情形进行了同样的计算,与前述方法计算结果的对比显示,考虑区域应力场的计算方式所得库仑破裂应力变化图像,能够更好地与余震及区域中小地震空间分布图像相吻合。

Abstract:

This paper calculates the static stress changes generated by the Yushu MS7.1 earthquake in Qinghai Province.On the basis of regional stress,we take into account the static stress change triggered by the Yushu MS7.1 earthquake to find the optional fault plane.We then calculate the coulomb stress changes on the optional fault.The results indicate that most of aftershocks are triggered by the main shock.The image of the coulomb stress changes is also in accord with regional earthquakes（ML≥3.0） distribution,but the value is lower than 0.01MPa.In addition,this paper calculates the coulomb stress changes of the aftershock fault planes same as the mainshock.The comparison with the results in the previous calculation shows that the image of coulomb stress changes obtained by using ＂optional fault＂ method is more consistent with the distribution of Yushu aftershocks and regional earthquakes.[著者文摘]