汶川Ms 8.0地震断裂带逸出气（CO2、Rn和Hg）对环境的影响研究

A large number of earthquakes were accompanied with huge degassing in earth day in and day out, but degassing of earth was neglected by scientists in process of research of global climate change. Therefore, the study will utilize gas geochemical method to research the following contents: (1) the spatial variation of CO2, Rn and Hg flux in soil gas in different segment of the fault zone related by the Wenchuan Ms 8.0 earthquake, (2) the total contribution of CO2, Rn and Hg in different segment of the fault zone related by the Wenchuan Ms 8.0 earthquake, (3) Environmental Effect of Rn和Hg in soil gas in fault zone related by the Wenchuan Ms 8.0 earthquake. It is significant to research the Environmental Effect of degassing of seismic faults.

地球上每天都发生大量的地震，都伴有大量气体排气，然而，地震排气在全球气候变化研究中是被忽视的。因此，本项目利用土壤气体地球化学方法研究：（1）汶川Ms 8.0地震断裂带不同段内土壤气CO2、Rn和Hg的浓度和通量空间变化，（2）汶川Ms 8.0地震破裂带内CO2和Hg对大气的总排放量；(3) 汶川Ms 8.0地震断裂带不同段内土壤气Rn和Hg环境效应，这对研究地震断裂带脱气对大气环境影响有重要意义。

地震活动断裂带能够向大气释放大量的温室气体、放射性气体和有毒气体（CO2、CH4,、Rn和Hg），并对大气环境的影响产生复杂的影响。利用静态暗箱法，对汶川Ms 8.0地震破裂带CO2、Rn和Hg脱气强度进行实地测量，并计算了CO2和Hg脱气对大气的年贡献量。结果表明：（1）破裂带土壤气中CO2、CH4、Rn和Hg异常浓度最大值分别可以达到7.98%、2.38%、524.30 k Bq/m3和161.00 ng/m3；破裂带CO2、Rn和Hg脱气平均通量是34.95 g m-2d-1、36.11 m Bq m-2s-1和26.56 ng m-2h-1，最大值分别达到259.23 g m-2d-1、580.35 m Bq m-2s-1和387.67 ng m-2h-1。（2）汶川Ms 8.0地震破裂带向大气脱气的CO2年贡献量是0.95 M t，Hg的年贡献量是15.94 kg。汶川Ms 8.0地震破裂带破裂CO2、CH4、Rn和Hg等的脱气强度，不仅与破裂带渗透率有关，还与断裂带浅部存在的气藏、煤层以及磷矿层等气体源有重要的联系。