静态应力触发在应用中存在问题的讨论以玉树地震为例

大地震应力触发概念自提出至今被广泛应用。 库仑应力与后续地震活动对应效果受到多种因素影响。 其中, 不同深度断层滑动量不同导致不同深度静态库仑应力图像差异, 选取哪一个深度的应力图像来讨论后续地震趋势是一个重要问题。 本文提出一个计算方法, 首先计算不同深度静态库仑应力, 然后在同一个位置取不同深度库仑应力最高值, 绘制静态应力分布图像, 并以2010年玉树地震为例, 结合地震活动及静态库仑应力分布对这种计算方法的效果进行对比。 结果显示, 按照本文提出的计算方法, 利用不同学者给出的玉树地震破裂模型计算均显示, 玉树地震后2年内3级以上余震几乎全部发生在库仑应力增加区。

An Issue on Coulomb Static Stress Triggering Study:Applied to the 2012 Yushu Earthquake

Static stress change has been widely used since the concept of earthquake triggering was proposed. Corresponding effect of Coulomb failure stress of major earthquake and its aftershocks is influenced by many factors. Among them, fault slips at different depths lead to differences of the static Coulomb stress image at depth. To select the stress image at what depth to discuss the trend of subsequent earthquakes is an important issue. This paper presents a calculation method: Firstly, we calculate static Coulomb stresses at various depths, and then take the highest stress value at different depths at the same location to draw the static stress image. We take the 2010 Yushu earthquake for an example to assess the effect of the calculation method proposed in this paper combined with the seismic activity and the static Coulomb stress distribution. The results show that, in the two years after Yushu earthquake, the aftershock with magnitude larger than 3.0 occurred almost always in the Coulomb stress increase area, using two rupture models given by different researchers.