【摘要】 地震前的热异常大多是使用极轨卫星数据来研究,例如AVHRR和MODIS数据,其时间分辨率为一天2次.由于观测时间间隔约12小时,有可能会漏掉一些异常信息.使用高时间分辨率的静止卫星数据,研究了1998年1月10日张北M s6.2级地震前热红外异常,首次精细地刻画了该热异常的形态变化.结果表明1月5日夜间热异常出现在北京西北部,随后逐渐向东南方向扩展,整体覆盖在张家口—渤海断裂带上,到1月6日凌晨消失;其温度高出周边地表温度4 K~5 K;热异常的扩张与风速、风向有关,在卫星云图上表现出明显的随风摆动现象;该异常带之下的地表的温度与周边地表温度相同,据此推断该异常出现在空中,而不是地表,这是与前人完全不同的新结论.综合以上特征,推断认为该异常可能与地下气体溢出或者异常电磁场有关,而不是岩石受力破裂所致.更多还原

【Abstract】 Thermal anomaly before earthquakes had been widely studied during the last 20 years and the most widely used data is AVHRR or MODIS which has 1km spatial resolution.While their temporal resolution is low,namely 2 passes in one day,so it was possible that some thermal information could not be detected if these data were used.Here we used MTSAT geostationary data whose temporal resolution was 24 times one day,and studied thermal infrared anomaly before Zhangbei Ms6.2 earthquake which occurred on January 10,1998.The result showed that the anomaly appeared firstly at northwest Beijing city in the night of January 5,1998,then spread southeast,and finally disappeared in the morning of January 6,1998.It was located on the Zhangjiakou-Bohai fault systems exactly,and its temperature was 4K～5K higher than that of the land surface;the anomaly waved with wind direction and spread with wind speed;the land surface temperature below the anomaly was the same as the surrounding surface temperature.This showed that the anomaly was in the sky,not on the land surface.This was a totally new conclusion which was different with previously published results.According to these above features,we concluded that the anomaly may be related with the earth degassing or abnormal electromagnetic field,not the rock infrared radiation.更多还原