Preliminary study on abnormal characteristics of microtremor before Hebei Tangshan M5.1 earthquake in 2020
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摘要: 对2020年唐山M5.1地震前河北数字测震台承德、涞源、滦县、京唐港和迁西台站的数据资料进行分析，通过小波分解、功率谱分析、快速傅里叶变换等方法处理数据研究震前地脉动的异常变化特征。结果显示：① 唐山地震前，5个台均出现低频地脉动前兆异常，且4个台站低频异常具有一致性；② 4个台震前表现为振幅趋势上升，震后逐步下降；③ 4个台震前PSD变化具有一致性，震前趋势上升震后逐渐下降，且与振幅曲线呈相同趋势。Abstract: This paper analyzes the data of Hebei digital seismographic stations Chengde, Laiyuan, Luanxian, Jingtanggang and Qianxi before the Tangshan M5.1 earthquake in 2020. The data are processed by wavelet transform, power spectrum analysis, fast Fourier transform and so on to study the abnormal variation characteristics of the microtremor before earthquake. The results show that: ① Before the Tangshan earthquake, there are low-frequency microtremor precursory anomalies at 5 stations, and the anomalies of low-frequency at 4 stations are consistent. ② The amplitudes of the four stations increased before the earthquake and decreased gradually after the earthquake. ③ The PSD varieties of the four stations before earthquake are consistent. They all increased before the earthquake and gradually decreased after the earthquake, and the trend is the same as the amplitude curve.
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Key words:
- microtremor /
- Tangshan M5.1 earthquake /
- precursory anomaly /
- power spectral density
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图 1 2020年唐山M5.1地震震中及台站位置分布图
Figure 1. The distribution map of the epicenter and stations of the Tangshan M5.1 earthquake 2020
图 2 滦县台小波分解各细节功率谱
Figure 2. Power spectrum of each detail of wavelet decomposition at Luanxian station
图 3 滦县台实测与通过小波分解方法滤波后时间域信号、频率域信号和功率谱密度对比
从上到下依次为原始数据、频谱图和功率谱图。（a） 实测图；（b） 通过小波分解方法滤波后的图
Figure 3. Comparison of time domain signals, frequency domain signals and power spectral densities of measured and after filtering by the wavelet decomposition method data of the Luanxian station
From up to bottom is original data，spectrum and power spectrum. （a） Measured；（b） After filtering by the wavelet decomposition method
图 5 各台站地震前后地脉动优势频率随时间变化曲线
Figure 5. The variation of dominant frequency of the microtremor with time before and after earthquake at each station
图 6 各台站地震前后地脉动优势频率功率谱密度随时间变化曲线
Figure 6. The variation of power spectral density of dominant frequency of the microtremor with time before and after earthquake at each station
图 4 各台站地震前后地脉动振幅曲线
Figure 4. The amplitude of the microtremor before and after the earthquake at each station
表 1 各台站基本信息表
Table 1. Basic information of each station
序号 台站 台站代码 台基类型 场地类型 地震计 数采 环境地噪声
水平级别/类震中距/km 1 承德 CHD 基岩 山洞 BBVS-120 EDAS-24GN Ⅰ 144 2 京唐港 JTG 土层 井下 FSS-3DBH EDAS-24GN Ⅱ 76 3 涞源 LAY 基岩 地表 BBVS-60 EDAS-24GN Ⅰ 298 4 滦县 LUX 基岩 地表 BBVS-60 EDAS-24GN Ⅰ 27 5 迁西 QIX 基岩 地表 BBVS-60 EDAS-24GN Ⅱ 47 
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[1] 朱传镇,房明山,安镇文,等. 脉动与地震关系的初步探讨[J]. 地球物理学报,1977,20(1):20-32Zhu Chuanzhen,Fang Mingshan,An Zhenwen,et al. Preliminary study of the microseisms in relation to earthquake[J]. Acta Geophysica Sinica,1977,20(1):20-32 [2] 许建聪,简文彬. 地脉动在泉州市区地基土层场地评价中的应用[J]. 长安大学学报(地球科学版),2003,25(1):47-51Xu Jiancong,Jian Wenbin. Application of earth pulsation on site evaluation of Quanzhou[J]. Joural of Chang’an University (Earth Science Edition),2003,25(1):47-51 [3] Lee A W. On the direction of approach of microseismic waves[J]. Proceedings of the Royal Society A:Mathematical,Physical and Engineering Sciences,1935,149(1):183-199 [4] 董蕾. 大震前地脉动位移及其频谱特征研究[D]. 兰州: 中国地震局兰州地震研究所, 2011Dong Lei. Research on displacement and frequency spectrum characteristics of microtremors before strong earthquakes[D]. Lanzhou: Lanzhou Institute of Seismology, China Earthquake Administration, 2011 [5] 荆涛,孙艺,方禹心,等. 灯塔M5.1地震前沈阳地震台地脉动研究[J]. 防灾减灾学报,2019,35(4):41-45Jing Tao,Sun Yi,Fang Yuxin,et al. Study on the earth tremor of Shenyang seismic station before Dengta M5.1 earthquake[J]. Journal of Disaster Prevention and Reduction,2019,35(4):41-45 [6] 朱杰. 2014年云南鲁甸MS6.5地震震前地脉动异常[J]. 地震研究,2020,43(1):64-70 doi: 10.3969/j.issn.1000-0666.2020.01.008Zhu Jie. Anomalies of microtremors before the Yunnan Ludian MS6.5 earthquake in 2014[J]. Journal of Seismological Research,2020,43(1):64-70 doi: 10.3969/j.issn.1000-0666.2020.01.008 [7] 梁沙沙,高立新,薛丁,等. 阿拉善左旗5.8级地震前地脉动信号特征分析[J]. 地震工程学报,2018,40(4):808-814 doi: 10.3969/j.issn.1000-0844.2018.04.808Liang Shasha,Gao Lixin,Xue Ding,et al. Characteristics of ground pulse signals before the 2015 Alxa Left Banner M5.8 earthquake[J]. China Earthquake Engineering Journal,2018,40(4):808-814 doi: 10.3969/j.issn.1000-0844.2018.04.808 [8] 王梅德,于仁宝,张翠竹. 河南及邻区宽频带地震仪大震前地脉动信号分析[J]. 地震地磁观测与研究,2015,36(3):90-97 doi: 10.3969/j.issn.1003-3246.2015.03.017Wang Meide,Yu Renbao,Zhang Cuizhu. Analysis of pulse signal for broadband seismograph before large earthquakes in Henan and its adjacent area[J]. Seismological and Geomagnetic Observation and Research,2015,36(3):90-97 doi: 10.3969/j.issn.1003-3246.2015.03.017 [9] 张晓清,袁伏全,余娜. 2016年门源6.4级地震地脉动应变前兆异常特征初步研究[J]. 地震研究,2016,39(增刊1):35-42, 133Zhang Xiaoqing,Yuan Fuquan,Yu Na. A preliminary study on the precursor anomaly characteristics of microtremor strain of Qinghai Menyuan MS6.4 earthquake in 2016[J]. Journal of Seismological Research,2016,39(S1):35-42, 133 -
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