地震研究

通过对宽频带数字资料在昆仑山口西8.1级、汶川8.0级、民乐—山丹6.1级地震前地脉动幅度和频谱变化的研究,发现在震前几天地脉动有明显的扰动变化,初步认为是大震的低频波前兆异常。而强台风对地脉动也有类似的扰动现象。从频率域对比研究后初步认为:低频波前兆异常的可能频带范围是0.1～0.14 Hz,而强台风对地脉动的扰动频率范围是0.15～0.30 Hz。区别对待这两个频带,对跟踪强震临震异常有现实意义。

Through studying the amplitude and spectral change of microtremor before the west to Kunlun Mountain Pass M_S8.1earthquake,Wenchuan M_S8.0 earthquake and Minle-Shandan M_S6.1 earthquake based on the broadband digital data,we found that the microtremor disturbance changed obviously in a few days before the earthquake,which might be the low-frequency wave precursory anomalies before the large earthquake,and the strong typhoon has the similar disturbance to the microtremor. From the comparison of frequency domain of typhoon disturbance and precursor information of low frequency wave,we obtained that the frequency range of low-frequency wave precursor anomaly is 0.1～0.14 Hz,and the disturbance frequency range of strong typhoon on the microtremor is 0.15～0.30 Hz. To distinguish these two bands has the realistic significance to tracking the impending earthquake anomaly of the strong earthquake.

引言
1 宽频带数字资料低频波短临前兆信息
2 台风扰动
3 无台风相伴的地脉动异常变化
4 结论与讨论

图1 昆仑山口西MS8.1地震前地脉动记录及频谱分析结果<br/>(a)高台JCZ-1地脉动前驱波记录;(b)高台地脉动幅频图(信号长度3 600 s);(c)安西CTS-1地脉动<br/>前驱波记录;(d)安西地脉动幅频图(信号长度3 600 s)<br/>Fig.1 Microtremor records and their spectral analysis results before west to Kunlun Mountain Pass MS8.1 earthquake(a)microtremor precursory wave recorded by JCZ-1 seismometer at Gaotai Station;(b)amplitude-frequency curve of microtremor at Gaotai Station(signal length is 3 600 s);(c)microtremor precursory wave recorded by CTS-1 seismometer at Anxi Station;(d)amplitude-frequency curve of microtremor at Anxi Station(signal length is 3 600 s)

图1 昆仑山口西MS8.1地震前地脉动记录及频谱分析结果
(a)高台JCZ-1地脉动前驱波记录;(b)高台地脉动幅频图(信号长度3 600 s);(c)安西CTS-1地脉动
前驱波记录;(d)安西地脉动幅频图(信号长度3 600 s)
Fig.1 Microtremor records and their spectral analysis results before west to Kunlun Mountain Pass MS8.1 earthquake(a)microtremor precursory wave recorded by JCZ-1 seismometer at Gaotai Station;(b)amplitude-frequency curve of microtremor at Gaotai Station(signal length is 3 600 s);(c)microtremor precursory wave recorded by CTS-1 seismometer at Anxi Station;(d)amplitude-frequency curve of microtremor at Anxi Station(signal length is 3 600 s)

图2 汶川MS8.0地震前地脉动频谱分析及台站分布图<br/>(a)成都JCZ-1地脉动幅频图;(b)高台JCZ-1地脉动幅频图; <br/>(c)兰州CTS-1地脉动幅频图;(d)台站位置及震中分布图<br/>Fig.2 Spectral analysis of microtremor before Wenchuan MS8.0 earthquake and the distribution of stations (a)amplitude-frequency curve of microtremor recorded by JCZ-1 seismometer at Chengdu Station;(b)amplitude-frequency curve of microtremor recorded by JCZ-1 seismometer at Gaotai Station;(c)amplitude-frequency curve of microtremor recorded by CTS-1 siesmometer at Lanzhou Station;(d)distribution of station location and epicenter

图2 汶川MS8.0地震前地脉动频谱分析及台站分布图
(a)成都JCZ-1地脉动幅频图;(b)高台JCZ-1地脉动幅频图;
(c)兰州CTS-1地脉动幅频图;(d)台站位置及震中分布图
Fig.2 Spectral analysis of microtremor before Wenchuan MS8.0 earthquake and the distribution of stations (a)amplitude-frequency curve of microtremor recorded by JCZ-1 seismometer at Chengdu Station;(b)amplitude-frequency curve of microtremor recorded by JCZ-1 seismometer at Gaotai Station;(c)amplitude-frequency curve of microtremor recorded by CTS-1 siesmometer at Lanzhou Station;(d)distribution of station location and epicenter

表1 昆仑山口西8.1级地震及汶川8.0级地震对应强台风信息<br/>Fig.1 The information of severe typhoon corresponding to west to Kunlun Mountain Pass MS8.1 and Wenchuan MS8.0 earthquakes

表1 昆仑山口西8.1级地震及汶川8.0级地震对应强台风信息
Fig.1 The information of severe typhoon corresponding to west to Kunlun Mountain Pass MS8.1 and Wenchuan MS8.0 earthquakes

图3 LingLing台风期间恩施、昆明、乌鲁木齐台地脉动异常记录(8～16 s)(a)及频谱分析结果(2～16 s)(b)<br/>Fig.3 The microtremor anomalous recordings(8～16 s)(a)and their spectral analysis results (2～16 s)(b)observed at Enshi, Kunming, Urumqi Stations during the LingLing typhoon

图3 LingLing台风期间恩施、昆明、乌鲁木齐台地脉动异常记录(8～16 s)(a)及频谱分析结果(2～16 s)(b)
Fig.3 The microtremor anomalous recordings(8～16 s)(a)and their spectral analysis results (2～16 s)(b)observed at Enshi, Kunming, Urumqi Stations during the LingLing typhoon

图4 Rammasun台风过程(a)与昆明台地脉动信号(b)对比<br/>Fig.4 Comparison of process of Rammasun typhoon and microtremor signal at Kunming Station

图4 Rammasun台风过程(a)与昆明台地脉动信号(b)对比
Fig.4 Comparison of process of Rammasun typhoon and microtremor signal at Kunming Station

图5 民乐、山丹MS6.1地震前地脉动频谱分析图<br/>(a)高台JCZ-1地脉动幅频图;(b)安西CTS-1地脉动幅频图<br/>Fig.5 Spectral analysis of microtremor before Minle-Shandan MS6.1 earthquake(a)amplitude-frequency curve of microtremor recorded by JCZ-1 seismometer at Gaotai tation;(b)amplitude-frequency curve of microtremor recorded by CTS-1 seismometer at Anxi Station

图5 民乐、山丹MS6.1地震前地脉动频谱分析图
(a)高台JCZ-1地脉动幅频图;(b)安西CTS-1地脉动幅频图
Fig.5 Spectral analysis of microtremor before Minle-Shandan MS6.1 earthquake(a)amplitude-frequency curve of microtremor recorded by JCZ-1 seismometer at Gaotai tation;(b)amplitude-frequency curve of microtremor recorded by CTS-1 seismometer at Anxi Station

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备注

引言

1 宽频带数字资料低频波短临前兆信息

2 台风扰动

3 无台风相伴的地脉动异常变化

4 结论与讨论

期刊信息