强生银, 王宏伟, 温瑞智, 李春果, 任叶飞. 2021. 2021年5月21日云南漾濞MS6.4地震随机有限断层三维地震动模拟. 地球物理学报, 64(12): 4538-4547, doi: 10.6038/cjg2021P0404
QIANG ShengYin, WANG HongWei, WEN RuiZhi, LI ChunGuo, REN YeFei. 2021. Three-dimensional ground motion simulations by the stochastic finite-fault method for the Yangbi, Yunnan
M
S
6.4 earthquake on May 21, 2021.
Chinese Journal of Geophysics (in Chinese)
, 64(12): 4538-4547,
doi:
10.6038/cjg2021P0404
2021年5月21日云南省大理州漾濞县发生
M
S
6.4地震，震中附近遭受了强烈地震破坏.为预测此次地震的地震动影响场，利用震源运动学破裂随机模型，基于随机有限断层三维地震动模拟方法，给出了此次地震中28个触发强震动台站的三分量加速度时程模拟记录，并结合强震动观测记录，估计了此次地震的地震应力降及震源破裂过程，进一步模拟给出了此次地震中2823个虚拟观测点的三分量加速度时程.结果表明，模拟记录的峰值地面加速度（PGA）、峰值地面速度（PGV）与观测值接近，并体现了地震动峰值的衰减规律、近场饱和效应和破裂方向性效应；模拟与观测记录的5%阻尼比拟加速度反应谱（PSA）的幅值接近、谱形相似，在0.05~10 s周期段，模拟记录可以很好地预测地震动.基于三分量模拟记录给出了漾濞
M
S
6.4地震的仪器测定地震烈度图，与云南省地震局发布的烈度图接近，极震区烈度最高可达Ⅷ度，震源破裂方向性导致震中SE方向的烈度普遍高于NW方向，受局部场地条件影响沿洱海西侧出现高烈度异常区.
漾濞
M
S
6.4地震
随机有限断层法
地震动模拟
Abstract:
An
M
S
6.4 earthquake occurred in Yangbi county, Yunnan Province on May 21, 2021, and the epicentral area suffered from strong earthquake damage. The modified stochastic finite-fault method was used to reproduce the three-component ground motions at 28 strong-motion stations triggered in the Yangbi
M
S
6.4 earthquake using a series of source kinematic rupture models stochastically generated. Compared with the observed ground motions, the earthquake stress drop and the potential source rupture model were firstly estimated. Moreover, ground-motion acceleration time histories at 2823 virtual observation points produced by the Yangbi
M
S
6.4 earthquake were provided by the stochastic finite-fault simulation. The peak ground accelerations (PGAs) and peak ground velocities (PGVs) of the simulated ground motions, in good agreement with the observed values, well describe the distance attenuation, the near-field saturation effects and the rupture directivity effects. Meanwhile, amplitude and shape of 5%-damped pseudo spectral accelerations (PSAs) also show good agreement between the simulated and observed ground motions. The simulations well represent the observations at a wide period range from 0.05 to 10 s. The seismic intensity map was plotted based on the simulated three-component recordings, approximately consistent to that officially released by the Earthquake Administration of Yunnan Province. The epicentral meizoseismal area reached a highest intensity Ⅷ. Intensity to the SE of epicenter is generally higher than that to the NW due to the source rupture directivity. High intensity anomalous areas occur along the west bank of Erhai Lake due to the local site condition.
Key words:
Yangbi
M
S
6.4 earthquake
Stochastic finite-fault method
Ground motion simulation
Seismic intensity
Figure 8.
Seismic intensity of the Yangbi
M
S
6.4 earthquake derived from the simulated ground motions comparison with (a) seismic intensity officially released by the Earthquake Administration of Yunnan Province (blue lines) and (b) seismic intensity based on recordings obtained by seismic intensity stations (blue lines)
Huangfu G, Li Z H, Qin J Z, et al. 2007. Correlation of seismicity in Sichuan-Yunnan rhombic block.
Journal of Seismological Research
(in Chinese), 30(3): 205-209.
http://en.cnki.com.cn/Article_en/CJFDTOTAL-DZYJ200703002.htm
Kan R J, Zhang S C, Yan F T, et al. 1977. Present tectonic stress field and its relation to the characteristics of recent tectonic activity in Southwestern China.
Chinese Journal of Geophysics (Acta Geophysica Sinica)
(in Chinese), 20(2): 96-109.
http://www.researchgate.net/publication/284062543_Present_tectonic_stress_field_and_its_relation_to_the_characteristics_of_recent_tectonic_activty_in_southwestern_China
Pacheco J F, Scholz C H, Sykes L R. 1992. Changes in frequency-size relationship from small to large earthquakes.
Nature
, 355(2): 71-73.
http://www.nature.com/nature/journal/v355/n6355/pdf/355071a0.pdf
Wang Y P, Shen J, Wang Q, et al. 2003. On the lateral extrusion of Sichuan-Yunnan Block (Chuandian Block).
Earth Science Frontiers
(in Chinese), 10(S1): 187-192.
http://en.cnki.com.cn/Article_en/CJFDTOTAL-DXQY2003S1025.htm
Yu Y X, Li S Y, Xiao L. 2013. Development of ground motion attenuation relations for the new seismic hazard map of China.
Technology for Earthquake Disaster Prevention
(in Chinese), 8(1): 24-33.
http://en.cnki.com.cn/Article_en/CJFDTOTAL-ZZFY201301004.htm
赵翠萍, 陈章立, 华卫等. 2011. 中国大陆主要地震活动区中小地震震源参数研究. 地球物理学报, 54(6): 1478-1489. doi:
10.3969/j.issn.0001-5733.2011.06.007
http://www.geophy.cn//CN/abstract/abstract7981.shtml
Figure 1.
Epicenters of the Yangbi earthquake sequence, the triggered strong-motion observation stations during the
M
S
6.4 mainshock (a), and the macroseismic intensity map (b)
Figure 2.
Effect of stress drop on average and standard deviation over a period range from 0.05 to 10 s for PSA residual means for the simulated recordings at all stations
Figure 3.
Source rupture model of the Yangbi
M
S
6.4 earthquake
Figure 4.
Comparisons between PGAs, and PGVs from the simulated and observed ground motions
Figure 5.
Residuals of the PSAs at periods of 0.05~10 s between the simulated and observed ground motions
Figure 6.
Acceleration and velocity time histories and PSAs for the simulated ground motions
Figure 7.
Acceleration and velocity time histories, as well as PSAs simulated for both stations in each pair, which share the same hypocentral distances and are located in and opposite the direction of source rupture, respectively
Figure 8.
Seismic intensity of the Yangbi
M
S
6.4 earthquake derived from the simulated ground motions comparison with (a) seismic intensity officially released by the Earthquake Administration of Yunnan Province (blue lines) and (b) seismic intensity based on recordings obtained by seismic intensity stations (blue lines)
