青藏高原周缘三次强地震伴生的卫星高光谱遥感地球化学异常

利用卫星遥感高光谱AIRS数据, 获取了发生在青藏高原周缘三个不同构造单元的2017年8月九寨沟M_S7.0地震、 2019年4月西藏墨脱M_S6.3地震和2020年6月新疆于田M_S6.4地震伴生的CH₄气体地球化学异常。 用Matlab编程处理AIRS数据的结果表明, CH₄柱含量在三次地震前一周到半个月出现高值异常, 异常沿着断裂带分布, 其中断裂带的交会部位异常幅度较大。 由于地震所处的构造环境、 发震类型、 震级大小差异, 三个构造单元地震引起的CH₄气体浓度异常出现时间、 持续时间、 异常强度等方面存在一定差异。 三次地震前后遥感信息异常与地震活动对应较好, 这归因于在孕震应力场作用下地下气体沿着裂隙及裂缝的逸散作用。 研究结果对利用卫星高光谱分辨率遥感技术监测地震及其在大地震短临预测中的应用具有重要意义。

Satellite Hyperspectral Remote Sensing Geochemical Anomalies Associated with Three Strong Earthquakes Around the Qinghai-Tibetan Plateau

Based on the hyperspectral AIRS data, the data of CH₄ gas geochemical anomalies were obtained associated with the Jiuzhaigou M_S7.0 earthquake in August 2017, the Motuo M_S6.3 earthquake in April 2019 and the Yutian M_S6.4 earthquake in June 2020 in three different tectonic units around the Qinghai Tibet Plateau. The results processed with Matlab show that the content of CH₄ column appears high value anomaly about one week and a half months before the three earthquakes, and the anomaly is distributed along the fault zone, in which the anomaly amplitude at the intersection of the fault zone is larger. Due to the differences of tectonic environment, seismogenic type and magnitude, the occurrence time, duration and intensity of CH₄ gas concentration anomaly caused by earthquakes in three tectonic units are different. The anomaly of remote sensing information before and after the three earthquakes corresponds well with the seismicity, which is attributed to the underground gas escaping along the fractures fromed by the action of seismogenic stress field. The results are of great significance to the application of satellite high spectral resolution remote sensing technology in earthquake monitoring and short-term and impending prediction of large earthquakes.