基于山西数字地震台网2001 年1 月～ 2014 年10 月ML≥2. 0 地震震相到时数据，利用单台多震和达法计算山西地区波速比，并结合2010 年3 次MS≥4. 5 地震探讨地震前后波速比的变化特征。结果表明，在3 次地震前远台波速比异常出现时间较早，为震前6 个月至1 年;而近台波速比异常出现时间相对较晚，为震前10 天至2 个月不等，因此可通过远台、近台所围限的范围来缩小地震预测地点。东山台计算结果表明，发震时刻残差大小会影响波速比变化细节，因此在实际应用中，应首先确定每个台站发震时刻的残差阈值，以确保波速比计算结果的科学性和稳定性。

Based on the seismic phase data recorded by the Shanxi Digital Seismic Network from January，2001 to October，2014，this study calculates wave velocity ratio vP / vS of the Shanxi region by using the Wadati method of single station and multi-earthquake，and discusses the variation of wave velocity ratio vP / vS before or after 3 earthquakes with MS≥4. 5 in 2010． The results show that the anomaly of wave velocity ratio vP / vS at remote stations occurs from 6 months to 1 year before those 3 earthquakes． The anomaly of wave velocity ratio vP / vS at near stations occurred from 10 days to 2 months before the 3 earthquakes． We can shrink the earthquake prediction location by the range of remote and near stations． The Dongshan Seismic Station result indicates that the residuals of earthquake origin time influence the variation details of wave velocity ratio vP / vS ． Therefore，we should firstly determine the residual threshold of original times at each station in the practical applications，to ensure the scientificity and stability of calculated results of wave velocity ratio．

中国地震科技星火计划项目(XH12008Y、XH13004)、中国地震局青年骨干项目(20140305)和山西省基础研究基金(2012011029)共同资助