2013年芦山MS7.0地震震源区的地震波速度变化研究

摘要/Abstract

摘要： 本文利用四川区域台网的连续波形记录, 研究了2013年4月20日四川芦山地震前后震源区不同路径上介质速度的变化过程。结果显示, 在地震发生前, 本文使用的穿过震源区的所有路径上未能观测到速度变化, 而几个台站对(SMI-YZP、 XJI-EMS、 WCH-MDS)之间的路径上, 在地震发生后存在速度的快速减小, 量级为0.4%, 速度快速减小过程持续时间很短。只有少量台站对观测到速度变化, 表明芦山地震震源区介质变化不显著。

关键词: 背景噪声, 速度变化, 2013年芦山M_S7.0地震

Abstract: In this paper,we researched the temporal changes of different paths on medium speed before and after the Lushan earthquake on April 20, 2013, using continuous waveforms recorded by the Sichuan regional stations.The results show that, before the earthquake, we didn't observe speed changes on all the paths covering the focal region. It is the same as the cases of tectonic earthquakes above magnitude 6 that seismologists studied using the same method at home and abroad. After the earthquake, the velocity reduces rapidly on the paths of station pairs crossed the focal region, and the order of magnitude reaches 0.4%.This situation lasts for two months to disappear.

Key words: Ambient noise, Velocity change, The 2013 Lushan M_S7.0 earthquake

中图分类号:

P315.7

周晨, 周连庆, 张正帅, 赵翠萍. 2013年芦山M_S7.0地震震源区的地震波速度变化研究[J]. 地震, 2015, 35(3): 57-65.

ZHOU Chen, ZHOU Lian-qing, ZHANG Zheng-shuai, ZHAO Cui-ping. Temporal Changes of Seismic Velocity in the Source Region before and after the 2013 Lushan M_S7.0 Earthquake[J]. EARTHQUAKE, 2015, 35(3): 57-65.

参考文献

[1] 钱晓东, 苏有锦. 2008年攀枝花6.1级地震前后波速比变化研究[J]. 地震研究, 2013, 36(1): 15-23.
[2] Semenov A N.Variation in the travel time of transverse and longitudinal waves before violent earthquakes[J]. Bull Acad Sci USSR Geophys Phys Solid Earth, 1969, 3: 245-248.
[3] Aki K, De Fazio T, Reasenberg P, et al. An active experiment with earthquake fault for an estimation of the in situ stress[J]. Bull Seismol Soc Am, 1970, 60(4): 1315-1336.
[4] Poupinet G, Ellsworth W, Frechet J. Monitoring velocity variations in the crust using earthquake doublets: an application to the Calaveras faults California, [J]. J Geophys Res, 1984, 89: 5719-5731.
[5] Roel Snieder, Alexandre Grêt, Huub Douma, et al. Coda Wave Interferometry for Estimating Nonlinear Behavior in Seismic Velocity[J]. Science, 2002, 29: 2253-2255.
[6] Roel Snieder. The Theory of Coda Wave Interferometry[J]. Pure appl Geophys, 2006, 163: 455-473.
[7] Snieder R, Grêt A, Douma H, et al.Coda wave interferometry for estimating nonlinear behavior in seismic velocity[J]. Science, 2002, 295(5563): 2253-2255.
[8] Lobkis O I, Weaver R L. On the emergence of the Green’s function in the correlations of a diffuse field[J]. J Acoust Soc Am, 2001, 110(6): 3011-3017.
[9] Weaver R L, Lobkis O I. Diffuse fields in open systems and the emergence of the Green’s function[J]. J Acoust Soc Am, 2004, 116(5): 2731-2734.
[10] Campillo M, Paul A. Long-range correlations in the diffuse seismic coda[J]. Science, 2003, 299: 547-549.
[11] Shapiro N M, Campillo M, Stehly L, et al. High-resolution surface-wave tomography from ambient seismic noise[J]. Science, 2005, 305(5681): 233-236.
[12] Fry B, Stehly L, Campillo M, et al. Surface wave tomography of the cent ral alps: merging traditional source and non-traditional noise dispersion measurements[J]. Eos Trans AGU, 2005, 86(52), Fall Meet Suppl.
[13] Takagi N, Sato H, Nishimura T, et al. Group velocity measurement of Rayleigh and Love waves in nort heastern Japan on the basis of the cross-correlation analysis of microseisms[J]. Eos Trans AGU, 2005, 86(52), Fall Meet Suppl.
[14] Sens-Schönfelder C, Wegler U. Passive image interferometry and seasonal variations of seismic velocities at Merapi Volcano, Indonesia[J]. Geophysical Research Letters, 2006, 33, L21302.
[15] Brenguier F, Shapiro N, Campillo M, et al. Towards forecasting volcanic eruptions using seismic noise[J]. Nat Geosci, 2008, 1(2): 126-130.
[16] 刘志坤, 黄金莉. 利用背景噪声互相关研究汶川地震震源区地震波速度变化[J]. 地球物理学报, 2010, 53(4): 853-863.
[17] Jiu Hui Chen, Bérénice Froment, Qi Yuan Liu, et al. Distribution of seismic wave speed changes associated with the 12 May 2008 M_W7.9 Wenchuan earthquake[J]. Geophysical Research Letters, 2010, 37, L18302.
[18] Brenguier F, Campillo M, Hadziioannou C, et al. Postseismic relaxation along the San Andreas Fault at Parkfield from continuous seismological observations[J]. Science, 2008, 321(5895): 1478-1481.
[19] Hadziioannou C, Larose E, Baig A, et al. Improving temporal resolution in ambient noise monitoring of seismic wave speed[J]. Journal of Geophysical Research, 2011, 116, B07304.
[20] Zaccarelli L, Shapiro N M, Faenza L, et al. Variations of crustal elastic properties during the 2009 L’Aquila earthquake inferred from cross-correlations of ambient seismic noise[J]. Geophysiccal Research Letters, 2011, 38, L24304.
[21] 徐锡伟, 陈桂华, 于贵华, 等. 芦山地震发震构造及其与汶川地震关系讨论[J]. 地学前缘, 2013, 20(3): 11-20.
[22] 杜方, 龙锋, 阮祥, 等. 四川芦山7.0级地震及其与汶川8.0级地震的关系[J]. 地球物理学报, 2013, 56(5): 1772-1783.
[23] Bensen G D, Ritzwoller M H, Barmin M P, et al. Processing seismic ambient noise data to obtain reliable broad-band surface wave dispersion measurements[J]. Geophys J Int, 2007, 169: 1239-1260.
[24] Sabra K G, Gerstoft P, Roux P, et al. Extracting time-domain Green’s function estimates from ambient seismic noise[J]. Geophys Res Lett, 2005, 32, L03310.
[25] Liang C, Langston C A. Ambient seismic noise tomography and structure of eastern North America[J]. J Geophys Res, 2008, 113, B03309.
[26] Campillo M, Paul A. Long range correlations in the diffuse seismic coda[J]. Science, 2003, 299(5606): 547- 549.
[27] 房立华, 吴建平. 背景噪声频散曲线测定及其在华北地区的应用[J].地震学报, 2009, 31(5): 544-554.
[28] Grêt A, Snieder R, Scales J. Time-lapse monitoring of rock properties with coda wave Interferometry[J]. J Geophys Res, 2006, 111, B03305.
[29] Ratdomopurbo A, Poupinet G. Monitoring a Temporal Change of Seismic Velocity in a Volcano: Application to the 1992 Eruption of Mt. Merapi (Indonesia)[J]. Geophys Res Lett, 1995, 22(7): 775-778.
[30] Wegler U, Sens-Schönfelder C. Fault zone monitoring with passive image Interferometry[J]. Geophys J Int, 2007, 168(23): 1029-1033.
[31] Meier U, Shapiro N M., Brenguier F. Detecting seasonal variations in seismic velocities within Los Angeles basin from correlations of ambient seismic noise[J]. Geophys J Int, 2010, 181: 985-996.
[32] 徐锡伟, 陈桂华, 于贵华, 等. 5·12 汶川地震地表破裂基本参数的再论证及其构造内涵分析[J]. 地球物理学报, 2010, 53(10): 2321-2336.
[33] 赵翠萍, 周连庆, 陈章立. 2013年四川芦山M_S7.0级地震震源破裂过程及其构造意义[J]. 科学通报, 2013, 58(20): 1894-1900.