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.
出处
《地震学报》
CSCD
北大核心
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
关键词
玉树地震
DEMETER卫星观测
VLF电场频谱
信噪比
Yushu earthquake
DEMETER satellite observations
VI.F electricfield spectrum
signal to noise ratio
