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利用区域地震台网的地震波资料，由垂直向记录Ｐ和Ｓ振幅比值的拟合，反演得到松潘地震序列１５８个中小余震的震源机制解．分析表明虽然小震机制解的空间取向比较离散，但其优势取向和区域应力场相符。集中在３个地点的８８个小震机制解与离散分布在全区的７０个小震机制解之间没有显著差异．据此推论序列中３次大震之所以具有较大的逆冲滑动分量，系予存软弱面的空间取向决定，而非应力场的原因。序列中的中小余震并没有表现出逆冲滑动的优势，表明它们主要是震源区应力场调整的产物，且分布在一定的震源体积之中。
Using the seismic data from the regional seismological network, the focal mechanism solutions of 158 small and medium aftershocks of the Songpan earthquake sequence are obtained by the fitting of the P and S amplitude ratios recorded vertically. Analysis shows that although the spatial orientation of the small earthquake mechanism solution is relatively discrete, its dominant orientation is consistent with the regional stress field. There are no significant differences between the 88 small earthquake solutions and the 70 small earthquake solutions scattered in the whole area in the three places. According to the corollary sequence, the reason why the three large earthquakes have larger thrust sliding components is the spatial orientation of the weakened surface, rather than the reason of the non-stress field. The small and medium aftershocks in the sequence do not show the advantage of thrust slip, indicating that they are mainly the product of the stress field adjustment in the source region and are distributed in a certain amount of source volume.