通过2003年青海德令哈ML 6.7地震序列的主震和3个不同震级的余震震源机制解测定实例，展示了Snoke(2003)震源机制求解方法的应用过程和结果，提出了应用该方法需注意的问题。将同时利用了P波和S波初动方向及振幅比数据的测定结果与仅用P波初动方向数据的结果作了对比研究，说明仅用P波初动方向常常不能有效约束震源机制解，而Snoke方法增加使1用的SH波和SV波的初动方向以及SH波、SV波与P波的观测振幅比数据，使解答得到了更有效的约束，提高了解答的可信度。本试验研究说明，基于区域性的宽频带数字地震记录，利用Snoke震源机制求解方法，有可能测定出比较可靠的中、小地震的震源机制解。

Focal mechanisms of the 2003 Delingha, Qinghai province of China, ML 6.7 earthquake and its 3 aftershocks were determined using Snoke′s algorithm (http://equake.geos.vt.edu/focmec/) for focal mechanism (FM) determination. The authors discussed some problems, to which we should pay attention in applying the algorithm for FM study. Some FM solutions determined by using polarity and amplitude data of both P and S wave are compared with that obtained only by P polarity data analysis. The result indicates that use of additional data of SH and SV polarity, and amplitude ratio of SH or SV over P, did constrain the solutions efficiently. This research seems to see the prospects of applying Snoke′s method to FM determination of moderate and small earthquakes.