闽粤地区同震形变波记录序列分析及小波能谱特征
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摘要
基于闽粤地区10个地形变观测点40个测项的同震形变波记录,利用幅度比值和小波多尺度分析方法探讨其记录特点和传导机制,结果显示:1)同震形变波到时与震中距有关,波形记录含有d-P和d-S波,不同测项记录到的波形不一致,同测项的记录波形相似;2)幅度比值在一定程度上与震源方位有关,进一步反映其各向异性;3)通过互(自)相关计算和滤波处理,能识别出同震形变波的频带为0.02~0.04 Hz,峰值在0.025Hz附近;4)智利地震形变波序列小波能谱为64~254s,能量集中在128~254s;而尼泊尔地震形变波在不同测点区别较大,潮州台为16~32s,厦门台为16~64s。研究结果表明,形变记录中除面波外还包含体波成分,不同震源机制引起的同震形变波传导机制可能存在各向异性,这对于开展地震引发应变等研究有借鉴意义。
This paper uses sequence analysis and wavelet spectrum methods to discuss co-seismic deformation waves(CSDW)records characters and its conduct mechanism in Fujian-Guangdong area.The deformation data,based on 10 stations,includes 40 precursory anomalies in total.The result show that:(1)Arrival-time of CSDW is related to epicentral distance,the records include d-P and d-S waves,the records from different items are not consistent,and the same measured items are similar to the recorded waveform.(2)To a certain extent,the amplitude ratio shows the direction of the source,and further reflects the direction anisotropy of the amplitude ratio.(3)By calculating the cross(self)-correlation and filter processing,we can identify the CSDW bands in 0.02~0.04 Hz;the peak value is about 0.025 Hz.(4)The wavelet spectrum band of Chile earthquake CSDW is mainly 64~254 s,the main energy is concentrated in 128~254 s,which is different thanthe Nepal earthquake CSDW.Different measuring points are different,the band of Chaozhou and Xiamen station is 16~32 sand 16~64 s,respectively.Results suggest the CSDW records include P wave and S wave elements except surface waves;in addition,the conduction mechanism of CSDW,which is caused by different focal mechanisms,may be anisotropic.This study has reference significance for the study of earthquake induced strain.
This paper uses sequence analysis and wavelet spectrum methods to discuss co-seismic deformation waves(CSDW)records characters and its conduct mechanism in Fujian-Guangdong area.The deformation data,based on 10 stations,includes 40 precursory anomalies in total.The result show that:(1)Arrival-time of CSDW is related to epicentral distance,the records include d-P and d-S waves,the records from different items are not consistent,and the same measured items are similar to the recorded waveform.(2)To a certain extent,the amplitude ratio shows the direction of the source,and further reflects the direction anisotropy of the amplitude ratio.(3)By calculating the cross(self)-correlation and filter processing,we can identify the CSDW bands in 0.02~0.04 Hz;the peak value is about 0.025 Hz.(4)The wavelet spectrum band of Chile earthquake CSDW is mainly 64~254 s,the main energy is concentrated in 128~254 s,which is different thanthe Nepal earthquake CSDW.Different measuring points are different,the band of Chaozhou and Xiamen station is 16~32 sand 16~64 s,respectively.Results suggest the CSDW records include P wave and S wave elements except surface waves;in addition,the conduction mechanism of CSDW,which is caused by different focal mechanisms,may be anisotropic.This study has reference significance for the study of earthquake induced strain.
引文
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[2]狄樑,陆德明,丁建国.常熟地震台水管倾斜仪与垂直摆倾斜仪同震响应对比分析[J].大地测量与地球动力学,2013,33(增1):79-81(Di Liang,Lu Deming,Ding Jianguo.Comparative Analysis of Co-Seismic Response between Water-Tube and Vertical Pendulum Tiltmeters in Changshu Seismic Station[J].Journal of Geodesy and Geodynamics,2013,33(S1):79-81)
[3]赵斌,杜瑞林,张锐,等.GPS测定的尼泊尔MW7.9和MW7.3级地震同震形变场[J].科学通报,2015,60(28-29):2 758-2 764(Zhao Bin,Du Ruilin,Zhang Rui,et al.Co-Seismic Displacements Associated with the 2015 Nepal MW7.9Earthquake and MW7.3Aftershock Constrained by Global Positioning System Measurements[J].Chin Sci Bull,2015,60(28-29):2 758-2 764)
[4]徐韶光,熊永良,廖华,等.汶川地震同震形变的静态和动态分析[J].大地测量与地球动力学,2010,30(3):27-30(Xu Shaoguang,Xiong Yongliang,Liao Hua,et al.Static and Kinematic Analysis of Coseismic Deformation of Wenchuan Ms8.0Earthquake[J].Journal of Geodesy and Geodynamics,2010,30(3):27-30)
[5]方宏芳,刘序俨,张凯.漳州地震台伸缩仪和体应变仪同震响应分析[J].地震研究,2010,33(3):287-291(Fang Hongfang,Liu Xuyan,Zhang Kai.Analysis of the CoSeismic Response of Extensometer and Body Strain Gauge at Zhangzhou Seismic Station[J].Journal of Seismological Research,2010,33(3):287-291)
[6]李杰,刘希强,李红,等.利用小波变换方法分析形变观测资料的正常背景变化特征[J].地震学报,2005,27(1):33-41(Li Jie,Liu Xiqiang,Li Hong,et al.Analysis on Normal Background Characteristics about Deformation Observation Data on the Basis of Wavelet Transform Method[J].Seismologica Sinica,2005,27(1):33-41)
[7]Farge M.Wavelet Transform and Their Applications to Turbulence[J].Annual Review of Fluid Mechanics,1992,24(1):395-458