丽江7.0级地震滇西实验场区跨断层短基线短水准测量的变化特征

Characters of the Variation of Cross Fault Short baseline and Short range Leveling in Western Yunnan Earthquake Test Site Before Lijiang Earthquake (M=70)

通过对滇西实验场区跨断层短基线、短水准测量的计算分析表明：１９９６年２月丽江７０级地震前，滇西实验场区５个跨断层短基线、短水准测量的测点中，只有位于程海断裂带上的永胜测点（震中距８２ｋｍ）在震前１年左右出现巨变异常，而距震中最近的丽江测点（震中距４２ｋｍ），震前并没有显著的异常变化，但却有很大的同震变化。其它３个测点看不出与该次地震有明显联系的变化。尝试性地进行了两种计算，可能对孕震地区的判断有一定的参考价值。

By analysis of variation of cross fault short baseline and short range leveling in Western Yunnan Earthquake Test Site (WYETS),the results showed that:among five observation points of cross fault short baseline and short range leveling in WYETS before Lijiang earthquake (M=70),only Yongsheng observation point (epicentral distance:82km) which is located at Chenghai fault appeared great variations about one year before the earthquake.And the nearest point Lijiang observation point (epicentral distance:42km) presented great coseismic variation,but did not present obviously anomalous variation before the earthquake.There were no significant variations related to the earthquake at other three observation points.Two methods had been used in the process of observation data analysis and some valuable results had been obtained.