祁连山地震带中强地震前热红外异常研究

Thermal Infrared Anomalies prior to the MS ≥ 5 Earthquakes in the Qilianshan Seismic Zone

摘要:

对祁连山地震带1991-2004年间发生的13次中强地震,采用NOAA卫星热红外遥感资料数据库进行地面温度的时空网格化扫描,获得多年连续的热红外时序,研究地震前后的温度演化过程,提取震前地表温度的异常特征。研究结果表明,有38%的地震在震前出现了热红外异常现象,有的表现为温度降低,有的则表现为温度升高,体现了地震诱发因素的复杂性;温度异常幅度均为2~3℃,异常出现的时间均在2个月内;震级越大,异常越明显,但并非所有6级以上地震都比5~6级地震的热红外异常明显。

Abstract:

Using thermal infrared data from NOAA,the temperature-time sequences of epifocal areas in small windows were scanned prior to 13 earthquakes that occurred in the Qilianshan seismic zone from 1991 to 2004.Next,the continuing thermal infrared temperature-time sequences over time and the abstract surface temperature abnormality phenomena before these earthquakes occurred were obtained.The research results found that there were thermal infrared anomalies prior to 38% of the earthquakes,the surface temperature during some earthquakes increased abnormally,and the surface temperature during others decreased abnormally.These results demonstrate the complexity of the inducing factors of earthquakes.The amplitude of anomalies were consistently 2°C to 3°C,and the anomalies always appeared two weeks before the earthquakes occurred.It was also found that when the earthquake magnitude was a maximum,the surface temperature anomaly phenomenon was the most noticeable.For example,in the M_S6.1 earthquake of 2003 in Minle.However,not all temperature anomaly phenomena for earthquakes M_S > 6.0 were noticeable in comparison to earthquakes in the range of 5.0< M_S < 6.0.