【摘要】 针对短临地震预报难尤其是临震预报难问题,以2008年汶川地震为背景,对受地震影响严重的川、滇、陕、甘、渝5个省市区域内的深层地下水位进行了分析,发现在龙门山断裂带所在的四川省及其NE方向的甘肃省区域,共有7口井水位表现为明显的临震异常,异常形态包括振荡型、脉冲型和阶升型。利用小波变换方法对振荡型及脉冲型异常进行分析,结果表明:临夏、古浪横梁和清水等井水位信号中存在着周期为2～8 min,振幅为5～59 mm的前驱波波形,这是由于震源体慢破裂过程中发出的地震波造成的。阶升型异常幅度较大,分别为129.4 cm和340.8 cm,从震前几分钟一直持续到震后,未恢复到震前状态;表明引起震时地下水剧烈变化的动力作用在震前已经开始,震时变化只是在此基础上进一步发展与加剧。更多还原

【Abstract】 Due to middle-term and impending anomaly forecast of earthquake is relatively difficult,taking Wenchuan earthquake in 2008 as the studying background,choosing the severely affected areas such as Sichuan,Yunnan,Shaanxi,Gansu and Chongqing Province/City as study region,the deep groundwater-level anomaly characteristic was analyzed in this study.In Sichuan region,where Longmen Mountain fault locates,and Gansu region along NE direction of Longmen Mountain fault,seven wells groundwater-level appeared clear impending ano-maly,including oscillatory type,pulse type and step type.By wavelet transformation analysis to oscillation and pulse anomaly of groundwater level,the results showed that Linxia,Gulanghengliang,Qingshui well water-levels exist similar precursor waveform,with a cycle of 2-8 min and an anomaly amplitude 5-59 mm.They were the results of seismic wave from source slow rupture of source body,indicating the coming of large earthquake.On the other hands,step-type anomaly amplitudes were relatively large,respectively 129.4 cm and 340.8 cm.They last from a few minutes before earthquake to after earthquake,and couldn’t recover the state before earthquake.It showed that the driving function,which caused dramatic changes of groundwater-level,had begun before earthquake,and their coseismic anomaly were further developed and intensified on the basis of it.更多还原