云南景谷M_S6.6地震前地磁ULF异常信号变化

Anomalies of ULF Magnetic Field Variations Prior to the Jinggu M_S6.6 Earthquake

采用云南地磁台站通海、景谷、勐腊磁通门记录秒采样数据,分析了3个台站当地时间22时到次日2时(世界时15—19时)之间垂直分量(Z)和水平分量(H)在特定0.01～0.05Hz范围的辐射谱强度。结果表明,在震前垂直分量并没有强烈和清晰的ULF信号强度,3个台站水平分量ULF信号趋势性上升和震时反常的信号衰减现象,则反映震前超低频地磁信号产生扰动。

This study focus on ULF data before the Jinggu M S6.6 earthquake on October 7, 2014 from three geomagnetic stations in Yunnan province： TongHai, JingGu, MengLa, analyze the Z component and H component of the data during the local nighttime period （LT = 22h to 02h, UTC = 15h to19h ） at a particular frequency of 0.01 ~ 0.05 Hz. The result shows there seems no clear signature of Z component ULF radiation. However, the most significant fact shows that H component ULF signal raised before the earthquake, and depressed at occurrence moment of the earthquake, which suggests that the lower ionosphere was occurred before the earthquake.