中文摘要：

继2008年汶川8.0级大地震＂突然＂发生后,2013年4月20日芦山7.0地震的＂突然＂发生,再一次表明大地震短临监测的重要性和迫切性。芦山地震后,对中国大陆构造环境监测网络（简称＂陆态网络＂）连续重力台站的重力观测资料进行了处理分析,首次发现震前存在两种不同性质的重力扰动信号,周期分别为8~11s和6~8s。其中,周期为8~11s的重力扰动信号从大震前1天开始逐渐增大,并于震中距大于1 570km时消失;周期为6~8s的重力扰动信号从大震前7天开始逐渐增大,能够被所有台站监测到。两种重力扰动信号可能反映了芦山地震孕震过程的两个不同阶段,对进一步揭示芦山地震孕震机制具有重要的参考意义。

英文摘要：

The‘accidental＇occurrence of Lushan 7.0earthquake on April 20,2013following the‘accidental＇occurrence of 2008 Wenchuan earthquake,indicated the importance and urgency of strengthening impending earthquake monitoring once again. We processed and analyzed the gravity data of Crustal Movement Observation Network of China（CMONOC）after Lushan earthquake and,for the first time,found two different gravity disturbance signals with period of 8-11seconds and of 6-8seconds respectively before the earthquake.The former gravity disturbance signal increased for one day before the earthquake happening,while the latter signal increased for seven days before the earthquake happening.Moreover,the former signal cannot be monitored when the epicentral distance exceeds 1570km,while the latter signal can be observed by any gravity station.The two different gravity disturbance signals may indicate two different stages of Lushan earthquake seismogenic process,and are significant for the further revelation of Lushan earthquake seismogenic mechanism.