利用改进型图像信息方法研究玉树地震前电离层电子浓度异常现象

Study on anomaly of ionospheric electron density before the Yushu earthquake using modified pattern informatics method

简单扼要地介绍了DEMETER卫星的发展历程、电离层地震前兆异常的识别和提取方法以及改进型图像信息方法(Modified Pattern Informatics method,简称MPI方法)的具体计算过程。笔者利用MPI方法处理了2010年4月13日23时49分(世界时)玉树MS7.1地震前1个月震中上空30°×50°范围内DEMETER卫星监测到的电离层电子浓度,生成时空演化图像。结果显示,2010年3月16—28日玉树震中上空电子浓度变化较为平缓;3月30日震中上空南部开始出现电子浓度高值异常;随着发震时刻的临近,震中上空电子浓度高值异常逐渐显著;玉树地震发生当日(4月13日)研究区域上空电子浓度最为显著。从研究结果我们可以看出,MPI方法在提取DEMETER卫星数据的地震异常方面有一定的时空鉴别力。

This paper briefly introduces the development course of the DEMETER satel-lite, the identification and extraction method of the anomaly of ionospheric earthquake pre-cursor, and the specific calculation process of modified pattern informatics method （referred as MPI method）. Using the MPI method to process the ionospheric electron density data monitored by the DEMETER satellite within the scope of 300 X 500 above the epicenter, the spatio-temporal evolution images one month before April 13, 2010 23 ： 49 （ world time） Yushu Ms7. 1 earthquake was generated. The results showed that the change of electron density over the epicenter of Yushu was relatively gentle from March 16 to March 28, 2010 ; An unusually high-value of electron density began to appear over the south of the epicenter on March 30 ; With the approaching of the shock moment, the high-value of electron densityover the epicenter is significantly higher; The electron density over the epicenter of study ar-ea was the most significant on the day of the Yushu earthquake （April 13）. The results of the study show that the MPI method has some spatio-temporal discrimination in extracting the seismic anomalies of DEMETER satellite data.