2016年12月25日智利M7.6地震球型自由振荡检测
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摘要
智利M7.6的地震激发了地球自由振荡,利用中国数字台网(CDSN)的10个台站记录到7 d的VHZ波形数据,采用功率谱密度估计方法,在没有滤波的情况下,提取了2016年12月25日智利地震激发的地球球型自由振荡基频振型_0S_4～_0S_(53)和一系列的谐频振型,并与PREM模型的理论自由振荡频率峰值进行对比,发现2.5～4.5×10~(13)Hz的频率值与PREM模型预测的球型自由振荡周期符合得很好,说明本次地震确实激发了全球范围内的自由振荡,而4.5～6×10~(13) Hz的频率值稍微有偏离,这是由于地壳的横向不均匀所致,可以用来研究地球内部的构造。
The Chile M7.6 earthquake excited the free oscillation of the earth. By using 7 d VHZ waveform data recorded by 10 stations of Chinese digital network(CDSN) and the power spectral density estimation method,in no case of filtering, the paper extracted the fundamental frequency _0S_4～_0S_(53) and a series of harmonious vibration frequency of the free oscillation of the earth vibration excited by the Chile earthquake on December 25~(th), 2016, and compared with the theoretical free oscillation frequency peak value of the PREM model. The results show that the 2.5～4.5×10~(13)Hz frequency value of the spherical free oscillation cycle prediction and PREM model are in good agreement. The earthquake does stimulate the global range of free oscillation, and 4.5～6×10~(13)Hz frequency value is slightly deviated duing to the horizontal unevenness of the earth's crust, which can be used to study the internal structure of the earth.
The Chile M7.6 earthquake excited the free oscillation of the earth. By using 7 d VHZ waveform data recorded by 10 stations of Chinese digital network(CDSN) and the power spectral density estimation method,in no case of filtering, the paper extracted the fundamental frequency _0S_4～_0S_(53) and a series of harmonious vibration frequency of the free oscillation of the earth vibration excited by the Chile earthquake on December 25~(th), 2016, and compared with the theoretical free oscillation frequency peak value of the PREM model. The results show that the 2.5～4.5×10~(13)Hz frequency value of the spherical free oscillation cycle prediction and PREM model are in good agreement. The earthquake does stimulate the global range of free oscillation, and 4.5～6×10~(13)Hz frequency value is slightly deviated duing to the horizontal unevenness of the earth's crust, which can be used to study the internal structure of the earth.
引文
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[13]万永革.数字信号处理的MATLAB实现.(第二版)北京:科学出版社,2010.
[14]雷湘鄂,许厚泽,孙和平.由5个国际超导重力仪台站资料检测到的秘鲁8.2级大地震所激发的球型自由振荡现象[J].中国科学,2004,34(5):483-491.
[15]邱泽华,马瑾,池顺良.钻孔差应变仪观测的苏门达腊大地震激发的地球环型自由振荡[J].地球物理学报,2007,50(3):797-805.
[16]宋秀青,于海英.印度洋9.0级大地震激发的基频地球球型振荡[J].地震地磁观测与研究,2005,26(4):13-17.
[17]李振月,万永革,汪园园,等.中国数字地震台网记录的2014年10月14日M7.3萨尔瓦多地震地球球型自由振荡研究[J].华南地震,2016,36(1):69-77.
[18]周公威,张伯明,吴忠良,等.中国数字地震台网的现状和近期发展[J].地震学报,2005,27(1):109-116.
[2] Benioff H,Press F,Smith S. Excitation of the free oscillations of the earth by earthquakes[J]. GeophysRes,1961(66):605-619.
[3]傅承义,陈运泰,祁贵仲.地球物理学基础[M].北京:地震出社,1985.
[4] Nowroozi A A. Characteristic periods of fundamental and overtone oscillations of the Earthfollowing a deep-focus earthquake[J]. Bulletin of the Seismological Society of America,1972,62(1):247-274.
[5]万永革.地震学导论[M].北京:科学出版社,2016.
[6]雷湘鄂,许厚泽,孙和平.利用超导重力观测资料检测地球自由振荡[J].科学报,2002,47(18):1432-1436.
[7]严珍珍,张怀,杨长春,等.地震激发的地球自由振荡研究综述[J].地球物理学进展2008,23(3):686-693.
[8] Ness N R,Harrison C T,Slichter L B. Observation of the free oscillation of the earth[J]. Geophys Res,1961(66):621-629.
[9]万永革,周公威,郭燕平.中国数字地震台网记录的昆仑山口西地震的球型自由振荡[J].地震,2005,25(1):31-40.
[10]万永革,周公威,郭燕平,等.昆仑山口西地震激发的地球环型振荡[J].防灾减灾工程学报,2004,24(1):1-7.
[11]万永革,盛书中,周公威,等.中国数字地震台网记录的苏门答腊-安达曼地震激发的地球球型自由振荡的检测[J].地震学报,2007,29(4):369-381.
[12] VanCamp M. Measuring seismic normal modes with the GWRC021 superconducting gravimeter[J]. Phys Earth Planet Inter,1999,116:81-92.
[13]万永革.数字信号处理的MATLAB实现.(第二版)北京:科学出版社,2010.
[14]雷湘鄂,许厚泽,孙和平.由5个国际超导重力仪台站资料检测到的秘鲁8.2级大地震所激发的球型自由振荡现象[J].中国科学,2004,34(5):483-491.
[15]邱泽华,马瑾,池顺良.钻孔差应变仪观测的苏门达腊大地震激发的地球环型自由振荡[J].地球物理学报,2007,50(3):797-805.
[16]宋秀青,于海英.印度洋9.0级大地震激发的基频地球球型振荡[J].地震地磁观测与研究,2005,26(4):13-17.
[17]李振月,万永革,汪园园,等.中国数字地震台网记录的2014年10月14日M7.3萨尔瓦多地震地球球型自由振荡研究[J].华南地震,2016,36(1):69-77.
[18]周公威,张伯明,吴忠良,等.中国数字地震台网的现状和近期发展[J].地震学报,2005,27(1):109-116.