利用甘肃前兆台网观测资料进行时空扫描，发现地下流体参量、地倾斜等在甘肃酒泉金塔5.4级地震前10天内出现了一系列异常变化，鼎新—德令哈基线在两年半的时间内缩短5mm；短临异常主要出现在距震中200km范围的台站，时间是3月中旬和4月下旬；临震异常集中出现的时间是4月28日至5月1日。距离震中较近的高台倾斜完整记录下酒泉金塔MS5.4地震发生过程中岩土石受力变化的全部过程，提供了地震孕育和发生的完整演化资料，对完善地震理论模型和地震预测有积极的研究价值。%An earthquake of MS 5.4 occurred at the boundary between Jinta County,Jiuquan City, Gansu Province and Ejina County,Alashan City,Inner Mongolia Autonomous Region in the north Jinta- Huahai Basin (south margin of Beishan)of the active Altun fault belt on May 3, 2012.We found that the values of groundwater radon from Jiayuguan,Lanzhou,Wushan,and Pingliang stations exhibit synchronous abnormal variations before and after April 22 within 90~900 km from the epicenter by time-space scanning of the observed data from the Gansu precursor network and calculating the slip change rate of groundwater radon and variation rate of base value.These abnormal variations were mainly presented as increasing groundwater radon value from 5.6% to 37%.From April 22,2012,the daily measured water level parameter increased a step with the amplitude increasing initially from 0.36% to 1% and then decreasing.The relation-ship between the abnormal variations in groundwater radon values observed from the Wushan, Pingliang,and Shilidian stations far from the epicenter and this earthquake must be further studied;however,this phenomenon is objective. n Deformation anomaly information from the observatory primarily indicates that the ground tilt in the EW and SN directions measured at the Gaotai station,170 km from the epicenter, decreases rapidly after April 1 1,2012.The value of ground tilt in both the SN and EW directions increases abruptly from April 1 9 and April 24,respectively,and the amplitude reaches 100% at 1 1:38 a.m.on April 30 and continues until 10:07 a.m.on May 2.In the EW direction,the value decreases rapidly to the minimum value from 10:00 a.m.on May 2 to 1 1:39 a.m.on May 3 and then increases rapidly and recovers to the level measured on May 2,which is contrary to the trend observed in the SN direction.The ground tilt values in both the EW and SN directions reach the maximum value after 1 1:39 a.m.on April 3 and stay out nearly 6 hours;subsequently,Jinta, Jiuquan experienced an earthquake of MS 5.4 at 18:1 9.The increase in Dingxin-Delingha baseline shortening velocity in 2010 indicates that the northeastern Qinlian Structure Belt was squeezed and the baseline shortened by 5 mm in two and a half years before the Jinta MS 5.4 earthquake. n A series of abnormal variations occurred 10 days prior to the Jinta MS 5.4 earthquake.The short-impending anomaly primarily appeared at the stations at a distance of 200 km from the epicenter from mid-March to late April.The impending earthquake anomaly occurred primarily between April 28 and May 1.The Gaotai station recorded the ground tilt data and the complete rock stress change process during the occurrence of the Jinta,Jiuquan MS 5.4 earthquake,thus providing complete evolution data with earthquake development and occurrence and has signifi-cant research value for the developing a perfect seismic theoretical model and earthquake prediction.
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