尼泊尔8.1级地震卫星热红外异常解析

发布时间：2018-11-28 07:53

【摘要】：针对2015年4月25日尼泊尔8.1级地震前后在震中区附近出现的大范围热红外异常,以中国静止卫星FY-2C/E亮温资料为数据源,采用功率谱相对变化法进行数据处理和资料分析,结果表明:震前热异常具有显著的时空特征,异常范围呈不规则带状分布,且随时间推移逐渐扩大,至震时异常面积趋于峰值,震中始终位于异常区域的边缘部位,震后异常快速收缩减弱,直至完全消失。该次热异常变化表现为初步显现、加速发展至逐步衰减的过程,持续时间在45天以上,特征周期为16天,相对变化幅度达12倍多。通过相似震例对比研究发现,该次地震与汶川大地震的热红外时空演化特征存在一定共性,主要体现在热异常的演化过程、异常形态、发震时刻及震中位置与异常区域的关系上,仅特征周期和特征幅值有所不同,应与各区域应力变化、气候因素及特殊的地质环境相关。这些认识对热异常与地震三要素的关系判定有一定启示作用,对地震热红外监测预报工作具有重要意义。
[Abstract]:In view of the large-scale thermal infrared anomalies around the epicentre of the April 25, 2015 Nepal M = 8.1 earthquake, the FY-2C/E bright temperature data from the Chinese geostationary satellite was used as the data source. The data processing and data analysis by using the method of relative variation of power spectrum show that the thermal anomalies before earthquakes have remarkable space-time characteristics, the anomalous range is irregular zonal distribution, and gradually expands with time. At the time of the earthquake, the abnormal area tends to peak, the epicenter is always located at the edge of the abnormal area, and the rapid contraction of the anomaly weakens after the earthquake, until it disappears completely. The thermal anomaly shows a process of initial appearance and accelerated development to gradual decay. The duration is more than 45 days, the characteristic period is 16 days, and the relative variation range is more than 12 times. Through the comparative study of similar earthquake cases, it is found that the characteristics of thermal infrared temporal and spatial evolution of this earthquake and Wenchuan earthquake have certain commonness, which is mainly reflected in the evolution process and abnormal shape of thermal anomaly. Only the characteristic periods and amplitudes are different in the relationship between the occurrence time and the epicenter location and the anomalous regions, and should be related to the regional stress changes, climatic factors and special geological environments. These understandings are helpful to judge the relationship between the thermal anomaly and the three elements of earthquake, and are of great significance to the work of seismic thermal infrared monitoring and prediction.
【作者单位】：中国地震局兰州地震研究所;中国地震局地震预测研究所兰州创新基地;
【基金】：兰州地球物理国家野外科学观测研究站开放基金项目(2014Y01)
【分类号】：P315.72

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