Y��Y--4 ���Ӧ��۲���Ϊһ����Ҫ��ǰ�׹۲��ֶΣ�����Ч�ؼ�¼����ǰ���Ӧ��Ӧ��仯�����ְ�ͼ����M3. 7 ������ǰ������Ӫ������M4. 3 ������ǰ������ʡ�ػ�̨������ʡӪ��̨Y��Y --4 ���Ӧ��۲�ֱ�۲⵽�����쳣�����Աȷ������ػ�̨�۲������쳣��̬Ϊ: �쳣--��ƽ--����-- ����Ծ; Ӫ�ڵ���̨�۲������쳣��̬Ϊ: �쳣--����--���������쳣��Ȼ��̬���죬���ṩ�˷ḻ��ǰ����Ϣ�����нϺõ�ʱЧ�ԡ�

Y��Y-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 Y��Y-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��