针对2015年4月15日鄂尔多斯块体西北缘阿拉善左旗5.8级地震,利用内蒙古地震台网数字波形资料,采用快速傅里叶变换,分析2015年1月1日至4月15日震前频谱特征,意在判断震前是否存在低频异常信号。结果显示:①在5.8级地震前,东升庙、石嘴山及乌海地震台的地震波形低频信号存在相同现象;②低频信号在震前10天开始出现,并间断持续至发震;③低频信号出现的时间不连续,且持续时间间隔逐步缩短。
Aiming at the Alagxa Left Banner 5 magnitude earthquake, occurred on the northwestern margin of Erdos block, by usage of the digital waveform data recorded by the seismic network of Inner Mongolia, the spectrum characteristics of seismic data from January 1, 2015 to April 15, before the earthquake, is analyzed with fast Fourier transform method to find out whether there were abnormal low frequency signals. The results showed:① Before the M 5.8 earthquake, the low-frequency signals of the seismic waveforms observed in Dongshengmiao, Shizuishan and Wuhai seismic stations were similar; ②The low-frequency signals started to appear 10 days before the earthquake and intermittently continued until the earthquake occurred; ③The occurrence of low frequency signals were not continuous and the duration of intermittent interval were shortened gradually.
2018,39(3): 115-120 收稿日期:2017-01-10
DOI:10.3969/j.issn.1003-3246.2018.03.017
基金项目:2017年度震情跟踪定向工作(项目编号:2017010120);内蒙古自治区科技厅重大专项
作者简介:梁沙沙(1987-),女,工程师,从事数字地震学工作。E-mail:liangshasha200611012@126.com
*通讯作者:格根,女,助理工程师,从事电磁及热红外分析工作。E-mail:83467029@qq.com
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