Precursory or atmospheric waves?Comments on“Analysis of characteristics of precursor wave of low frequent in Shanxi before Wenchuan MS8.0 earthquake” by Zhang et al (2009)
-
摘要: 2008年5月11日山西地区5个地壳形变测项出现了“前驱波”信号，但其真实的物理本质究竟如何？至今仍存质疑。为此，本文借助小波变换方法对气压波和“前驱波”在不同时、频段的相关性进行了较系统的诊断；还进一步将“前驱波”与短时气压波动所产生的干扰实例进行了对比分析。结果表明：这些“前驱波”并非源自汶川MS8.0地震，而主要是气压波动的干扰。Abstract: On May 11 2008, some“precursory waves”were obviously recorded at five stations in Shanxi Province, but their real physical nature is still under debate. To uncover these important phenomena, we adopt the wavelet transform method to diagnose the correlations between atmospheric and precursory waves at different frequency bands. Furthermore, we compare the typical variations induced by the fluctuations of atmospheric pressure to the “precursory waves”aiming to analyze the similarities between them. The results show that the physical origin of these “precursory waves”mainly comes from the atmospheric waves rather than from the Wenchuan MS8.0 earthquake.
-
Key words:
- precursory wave /
- atmospheric wave /
- Wenchuan earthquake /
- crustal deformation /
- wavelet transform /
- Shanxi Province
-
图 1 汶川MS8.0地震前山西地区观测到“前驱波”的台站分布 （a） 及具体测项 （分钟值）；（b） 侯马台；（c） 太原台； （d） 代县台；（e） 静乐井；（f） 朔州井
Figure 1. （a） Spatial distributions of the five stations （black triangles） in Shanxi Province in which the “precursory waves”（marked with red dashed rectangles） observed; Minute value curves of NS component of strain at Houma （b）, Taiyuan （c）, Daixian （d） starions; Minute value curves of water level in Jingle （e）, and Shuozhou （f）wells. The 2008 Wenchuan MS8.0 earthquake is marked with dashed red vertical line
图 2 洞体应变NS分量与短时气压波动的对比曲线 （分钟值）。（a） 太原台；（b） 代县台
Figure 2. Comparisons of the NS component of strain （black lines） with the short-period oscillation of barometric pressure （red lines） data with one-minute sampling rate recorded at Taiyuan （a） and Daixian （b）stations，respectively
图 3 洞体应变NS分量和气压的小波分析结果，绿色垂直虚线界定了“前驱波”出现的时段[15]
d1—d6依次为小波分解后第1—6层的细节部分，其信号对应的周期分别为2—4 min，4—8 min，8—16 min，16—32 min，32—64 min，64—128 min
Figure 3. Decomposition of the signals of the NS component of strain （black lines） and barometric pressure （red lines） for Taiyuan （a） and Daixian （b） stations into six levels （d1 to d6） using wavelet transform. The starting time and ending time of the precursory waves are marked with dashed green vertical lines[15]
The corresponding periods of decomposed signals （from d1 to d6） are 2—4 min，4—8 min，8—16 min，16—32 min， 32—64 min，and 64—128 min，respectively
图 4 太原 （a，b） 和代县台 （c，d） 洞体应变NS分量对短时气压波动的响应实例 （蓝色虚线框所标）
Figure 4. Evidence of atmospheric pressure-induced strain changes （marked by the dashed blue rectangle） for Taiyuan （a，b） and Daixian （c，d） stations ，respectively
-
[1] Sacks I S,Linde A T,Suyehiro S,et al. Slow earthquakes and stress redistribution[J]. Nature,1978,275(5681):599-602 doi: 10.1038/275599a0 [2] Cicerone R D,Ebel J E,Britton J. A systematic compilation of earthquake precursors[J]. Tectonophysics,2009,476(3-4):371-396 [3] Ito Y,Hino R,Kido M,et al. Episodic slow slip events in the Japan subduction zone before the 2011 Tohoku-Oki earthquake[J]. Tectonophysics,2013,600:14-26 doi: 10.1016/j.tecto.2012.08.022 [4] Kanamori H,Cipar J J. Focal process of the great Chilean earthquake May 22,1960[J]. Physics of the Earth and Planetary Interiors,1974,9(2):128-136 doi: 10.1016/0031-9201(74)90029-6 [5] Dieterich J H. Preseismic fault slip and earthquake prediction[J]. Journal of Geophysical Research:Solid Earth,1978,83(8):3940-3948 [6] Lund F. Interpretation of the precursor to the 1960 great Chilean earthquake as a seismic solitary wave[J]. Pure and Applied Geophysics,1983,121(1):17-26 doi: 10.1007/BF02590117 [7] 张晁军,石耀霖,马丽. 慢地震研究中的一些问题[J]. 中国科学院大学学报,2005,22(3):258-269 doi: 10.3969/j.issn.1002-1175.2005.03.002Zhang Chaojun,Shi Yaolin,Ma Li. Some problems in studying slow earthquakes[J]. Journal of the Graduate School of the Chinese Academy of Sciences,2005,22(3):258-269 doi: 10.3969/j.issn.1002-1175.2005.03.002 [8] Roeloffs E A. Evidence for aseismic deformation rate changes prior to earthquakes[J]. Annual Review of Earth and Planetary Sciences,2006,34:591-627 doi: 10.1146/annurev.earth.34.031405.124947 [9] Bykov V G. Sine-Gordon equation and its application to tectonic stress transfer[J]. Journal of Seismology,2014,18(3):497-510 doi: 10.1007/s10950-014-9422-7 [10] Kano M,Aso N,Matsuzawa T,et al. Development of a slow earthquake database[J]. Seismological Research Letters,2018,89(4):1566-1575 [11] Kanamori H. A slow seismic event recorded in Pasadena[J]. Geophysical Research Letters,1989,16(12):1411-1414 doi: 10.1029/GL016i012p01411 [12] Tsai V C,Kanamori H,Lambin J. The morning glory wave of southern California[J]. Journal of Geophysical Research:Solid Earth,2004,109(B2):B02307 [13] Lorenz R D,Kedar S,Murdoch N,et al. Seismometer detection of dust devil vortices by ground tilt[J]. Bull. Seismol. Soc. Amer.,2015,105(6):3015-3023 doi: 10.1785/0120150133 [14] 杨小林,危自根,杨锦玲,等. 飑线对定点地形变观测的影响特征与机理−以陕西关中盆地为例[J]. 中国地震,2019,35(3):465-475 doi: 10.3969/j.issn.1001-4683.2019.03.005Yang Xiaolin,Wei Zigen,Yang Jinling,et al. Ground deformation induced by a strong squall line:A case study in the Weihe basin,Shaanxi Province[J]. Earthquake Research in China,2019,35(3):465-475 doi: 10.3969/j.issn.1001-4683.2019.03.005 [15] 张淑亮,刘瑞春,宁亚灵,等. 汶川MS8.0地震前山西前兆低频前驱波特征分析[J]. 大地测量与地球动力学,2009,29(6):35-39Zhang Shuliang,Liu Ruichun,Ning Yaling,et al. Analysis of characteristics of precursor wave of low frequent in Shanxi before Wenchuan MS8.0 earthquake[J]. Journal of Geodesy and Geodynamics,2009,29(6):35-39 [16] 张小涛,刘杰,宋治平,等. 汶川MS8.0地震的前兆异常时空演化过程及其力学分析[J]. 地震,2018,38(2):72-83 doi: 10.3969/j.issn.1000-3274.2018.02.007Zhang Xiaotao,Liu Jie,Song Zhiping,et al. Temporal and spatial evolution of precursory anomalies of the 2008 Wenchuan MS8.0 earthquake and mechanical analysis[J]. Earthquake,2018,38(2):72-83 doi: 10.3969/j.issn.1000-3274.2018.02.007 [17] 晏锐,田雷,王广才,等. 2008年汶川8.0级地震前地下流体异常回顾与统计特征分析[J]. 地球物理学报,2018,61(5):1907-1921 doi: 10.6038/cjg2018M0162Yan Rui,Tian Lei,Wang Guangcai,et al. Review and statistically characteristic analysis of underground fluid anomalies prior to the 2008 Wenchuan MS8.0 earthquake[J]. Chinese Journal of Geophysics,2018,61(5):1907-1921 doi: 10.6038/cjg2018M0162 [18] Kroner C,Jahr T,Kuhlmann S,et al. Pressure-induced noise on horizontal seismometer and strainmeter records evaluated by finite element modelling[J]. Geophysical Journal International,2005,161(1):167-178 doi: 10.1111/j.1365-246X.2005.02576.x [19] 张凌空,吴利军,杨颖. 雷暴产生的气压突变对体应变与同井水位干扰的对比研究[J]. 中国地震,2012,28(1):69-77 doi: 10.3969/j.issn.1001-4683.2012.01.008Zhang Lingkong,Wu Lijun,Yang Ying. Comparative study of the interference of mutation pressure generated by thunderstorms with volume strain and same well water-level[J]. Earthquake Research in China,2012,28(1):69-77 doi: 10.3969/j.issn.1001-4683.2012.01.008 [20] 樊冬,尹传兵,李惊生,等. SS-Y型伸缩仪气压扰动影响的特征分析与数学改正[J]. 大地测量与地球动力学,2017,37(12):1313-1316Fan Dong,Yin Chuanbing,Li Jingsheng,et al. Analysis disturbance characteristics from air pressure change and mathematical correction of SS-Y tensometer[J]. Journal of Geodesy and Geodynamics,2017,37(12):1313-1316 [21] 谭善文,秦树人,汤宝平. 小波基时频特性及其在分析突变信号中的应用[J]. 重庆大学学报(自然科学版),2001,24(2):12-17Tan Shanwen,Qin Shuren,Tang Baoping. Time-frequency characteristic of wavelet base and its application transient signal detection[J]. Journal of Chongqing University (Natural Science Edition),2001,24(2):12-17 [22] Mentes G,Eperné-Pápai I. The effect of atmospheric pressure on strain measurement at the Sopron Observatory,Hungary[J]. Bulletin d'Information des Marées Terrestres,2002,137(3):10901-10906 -
下载:
点击查看大图
计量
- 文章访问数: 144
- HTML全文浏览量: 123
- PDF下载量: 19
