玉树地震前电离层VLF信号信噪比变化  

The signal to noise ratio disturbance of ionospheric VLF radio signal before the 2010 Yushu M_S7.1 earthquake

作　　者：姚丽[1,2] 陈化然[2] 何宇飞[2] 

机构地区：[1]中国地震台网中心,中国北京100045 [2]中国地震局地球物理研究所,中国北京100081

出　　处：《地震学报》2013年第3期390-399,451,共10页Acta Seismologica Sinica

基　　金：公益性行业科研专项“卫星VLF信噪比背景及地震异常特征研究”(201008007-04);国家科技支撑项目(2012BAK19B02-03)资助

摘　　要：2010年4月13日23点49分38秒(世界时),青海省玉树县发生了MS7.1地震.根据法国DEMETER卫星电场探测仪(ICE)实验数据,研究震区上空半径500km范围内电离层10—20kHz甚低频(VLF)电场频谱信噪比发现,玉树地震前3个不同频率的地面VLF发射站信号对应的信噪比均出现相同的变化特征,即震前DEMETER卫星1个重访周期内的平均信噪比明显减弱,而2009年相同时段和区域的平均信噪比并未出现相似变化趋势.分析认为,玉树地震孕震期信噪比衰减现象很可能是由地震-电离层耦合所致.In Yushu, Qinghai province, a strong earthquake took place at 23.49.38 UT on April 13, 2010, with a magnitude Ms7.1. Based on ICE ex- periments onboard the DEMETER satellite, the VLF signal in 10-20 kHz radi ated by three ground transmitters and received on board of DEMETER satellite revealed the attenuation of the signal to noise ratio averaged value in the region with a radius of 500 km from the earthquake epicenter in a revisited period of DEMETER just prior to the mainshock. On the other hand, there were no simi- lar phenomena in 2009; on the contrary we found an ascending SNR in the cor- responding time interval and spatial position. These ionospheric anomalies be fore the Yushu earthquake are highly regarded as resulting from the seismo ionospheric coupling.

关 键 词：玉树地震 DEMETER卫星观测 VLF电场频谱 信噪比 

分 类 号：P352[天文地球—空间物理学]