汶川M_S8.0地震前后龙门山断裂带CO和CH_4排气增强

Increasing of CO and CH_4 Gas Emission at Longmenshan Fault Zone before and after Wenchuan M_S8.0 Earthquake

利用卫星高光谱数据研究了汶川地震前后震中周围及沿断裂带相同面积区域的CO和CH_4总量的变化和相关程度。结果表明:(1)龙门山断裂带地区常年有地下气体沿断裂带向大气中释放,CO沿断裂带释放,受构造控制明显,而CH_4除了受构造控制影响外,还受川西地区地下天然气的弥漫式扩散影响;(2)汶川地震的发生促进了地下气体的释放,汶川地震前约1.5个月至震后3个月左右有大量的地下CO和CH_4气体沿龙门山断裂带释放到大气中,并且距离震中越近,排气量越大。研究结果对地震监测、地气交换和环境地球化学监测有重要意义。

Based on the satellite hyper-spectral data,we studied the variation and correlation of total column CO and CH_4 in the same areas around the epicenter and along the fault zone before and after the Wenchuan earthquake.The results indicated that：（ 1） The lager amount of gases emittied from the underground into the Wenchuan atmosphere along the Longmenshan Fault Zone throughout the year. The emission of CO along the fault was controlled obviously by the tectonic,while the emission of CH_4 was not only controlled by the tectonic,but also influenced by the diffuse emission of natural gas in the Western Sichuan area.（ 2） The emitted underground gas was induced by the Wenchuan M_S8.0 earthquake. A large number of CO and CH_4 emitted from underground into the atmosphere along Longmenshan Fault Zone from about 1.5 months before the earthquake to 3 months after the earthquake,and the closer to the epicenter,the larger the amount of emitted gases was. The obtained results are significant to the earthquake monitoring,gas exchange between atmosphere and solid earth and environmental geochemistry monitoring.