汶川地震前的甲烷浓度异常及大气增温耦合

发布时间：2018-05-20 14:18

本文选题：汶川地震 + 甲烷　；参考：《地学前缘》2017年03期

【摘要】：利用Aqua卫星红外探测器(AIRS)获得的大气甲烷浓度数据和康定、姑咱两地震台的气温数据,研究了2008年汶川8.0级地震前后龙门山断裂带周边大气甲烷浓度的时空演化特征及其与气温的耦合关系。结果表明:自2004年起松潘—甘孜地块上部便出现了显著的甲烷浓度升高现象;大气甲烷浓度变化受构造活动控制明显;随着发震时刻的临近,浓度的高值区自龙门山断裂带两端逐渐向震中西侧集中,地震当天浓度达到最高值;大气甲烷浓度的变化趋势与地表气温变化一致,但时间上稍有滞后,反映出甲烷由地下上涌到地表,再运移到高空的过程。最后,探讨了震前大气甲烷浓度变化的机理,认为甲烷的释放与壳幔应力状态以及上覆地壳裂隙的产生和扩容有关。
[Abstract]:The atmospheric methane concentration data obtained from the Aqua satellite infrared detector (AIRS) and the temperature data from the two seismological stations, Kangding and Kangding, The temporal and spatial evolution characteristics of atmospheric methane concentration around the Longmenshan fault zone before and after the 2008 Wenchuan M8.0 earthquake and its coupling relationship with air temperature were studied. The results show that since 2004, there has been a significant increase in methane concentration in the upper part of Songpan-Ganzi block, and the change of atmospheric methane concentration is obviously controlled by tectonic activity. The high value area of the concentration gradually concentrates from the two ends of the Longmenshan fault zone to the west side of the epicenter, and the concentration of methane in the atmosphere reaches the highest value on the day of the earthquake, and the change trend of the atmospheric methane concentration is consistent with the change of the surface temperature, but the time is slightly behind. This reflects the movement of methane from the ground up to the surface, and then to the upper air. Finally, the mechanism of change of atmospheric methane concentration before earthquake is discussed. It is concluded that methane release is related to the stress state of crust and mantle and the generation and expansion of cracks in the overlying crust.
【作者单位】：中国地震局地震研究所地震大地测量重点实验室;中国地质大学(武汉)地球科学学院;教育部三峡库区地质灾害研究中心;华中构造力学研究中心;
【基金】：中国地震局地震研究所所长基金项目(IS201556231)
【分类号】：P315.7

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