【摘要】 河西走廊地处青藏活动地块东北部边缘,为祁连山地震构造带和南北地震构造带的交汇部位,历史上曾发生过多次中强以上的破坏性地震。2008年5月12日汶川8.0级特大地震发生后,河西地震带是否会发生中强震是一个较受关注的问题。文中分析了河西走廊张掖、武威、酒泉盆地地下水中的Sr、He同位素特征。结果显示,这3个地区的地下水经历了3种不同的循环路径,不是源自黑河、石羊河、疏勒河的地表径流,而是祁连山降水在出山前下渗深大断裂后的补给。这表明河西走廊盆地内的断裂带现今活动性仍然很强,玉门、高台、民乐、永昌等位于断裂带交汇处或附近的区域未来发生中、强震的可能性较大,应加强对这些地区地下水的实时监测。更多还原

【Abstract】 The Hexi Corridor(37°17’N to 42°48’N;93°23’E to 104°12’E)is located in the northeast margin of Tibetan Plateau active block region.The deep fault zones trending WNW(northern boundary fault of the Qilianshan)and NNE(Altyn fault zone)are well developed.Medium and strong earthquakes ever occurred in history in these regions,especially at the junction region of Qilianshan seismotectonic zone and north-south seismotectonic zone.After Wenchuan earthquake Ms 8.0 occurred at 14:28:01.42 CST on 12 May 2008,all regions except Xinjiang,Jilin and Heilongjiang in China were affected by the great quake.It is a remarkable problem that how strong the coming earthquake in the Hexi seismic belt may be in the future time.In this paper,the authors have measured strontium and helium isotopic compositions of groundwater in Zhangye,Wuwei and Jiuquan Basins.It is concluded that the groundwater in these three basins are not originated from the runoff of Heihe River,Shiyanghe River or Shulehe River respectively,but from the supply of rainfall in the Qilianshan mountain front,which feeds the deep fault zones and then flows up over the Earth surface.The groundwater in different areas have different cycling routes.Therefore,the fault zones within the Hexi Basin are strongly active at present.The Yumen,Gaotai,Minle,and Yongchang Counties are located at or nearby the junction areas of the deep fault zones,so the occurrence probability of medium and strong earthquake in the future is quite high within the regions.It should be stressed to enhance the real-time monitoring of groundwater in the regions.更多还原