安图M3. 7 及柳树M4. 3 地震前后YＲY——4 钻孔应变观测曲线异常形态

YＲY--4 钻孔应变观测作为一种重要的前兆观测手段，能有效地记录地震前后地应力应变变化。吉林安图境内M3. 7 级地震前后及辽宁营口柳树M4. 3 级地震前，吉林省敦化台及辽宁省营口台YＲY --4 钻孔应变观测分别观测到曲线异常。经对比分析，敦化台观测曲线异常形态为: 异常--走平--发震-- 震后阶跃; 营口地震台观测曲线异常形态为: 异常--返回--发震。两次异常虽然形态各异，但提供了丰富的前兆信息，具有较好的时效性。

YＲY--4 borehole strain observation curve anomaly before and after the earthquakes of Antu M3. 7 and Liushu M4. 3

YＲY-4 borehole strain observation，an important precursor method，can effectively record stress and strain changes before and after earthquakes． Before and after the M3. 7 level earthquake in Antu of Jilin，and before M4. 3 earthquake in Liushu of Yingkou，Liaoning，the YＲY-4 borehole strains observed by the Dunhua Station of Jilin and Yingkou Station of Liaoning Province were separately shown in abnormal curves． Through comparative analysis，the abnormal curved morphology of Dunhua Station seismograph is: abnormal-going flat-earthquakepost earthquake steps; while the abnormal curved morphology in Yingkou Station seismograph is: abnormal-going back-earthquake． Although they are different，the fact still provided rich precursory information，which is significant for prediction in time on impending earthquake．