Broadband ground motion simulations applied to the Luding MS6.8 earthquake on September 5,2022 based on spectral element method
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摘要: 2022年9月5日12时52分四川甘孜州泸定县发生MS6.8地震,此次地震造成泸定县及其周边地域的严重破坏和人员的重大伤亡,为重现此次地震的地震动影响场,分析近场强地面运动的空间分布特征,将确定性的凹凸体震源模型与随机震源模型结合得到有限断层运动学混合震源模型,进而将上述混合震源模型开发到SPECFEM 3D谱元法开源代码中,实现了基于谱元法和运动学混合震源模型的泸定MS6.8地震的全过程宽频带(0.1—5 Hz)地震动模拟。首先,将模拟结果与6个台站的时程记录、对应的反应谱以及NGA-West2地震动衰减曲线进行比较,检验了方法的精度和适用性;进而给出了此次地震的三分量速度波场快照图,再现了地震波传播时近场地震动的方向性效应和局部场地效应;最后给出了泸定地区100 km范围内的地震动峰值加速度(PGA)和峰值速度(PGV)云图,分析了泸定地震下近场强地面运动的空间分布特征,并基于模拟结果给出了基于模拟结果的地震烈度分布图。结果显示,震中PGA接近600 cm/s2,PGV接近50 cm/s,烈度达到Ⅸ度,且由于泸定地区内高山峡谷地形对地震动的影响,地震动峰值在山顶和峡谷处明显放大,山顶处PGA和PGV分别放大1.9倍和1.5倍,峡谷谷底处PGA和PGV分别放大1.7倍和1.4倍,这里出现的地震放大现象以及可能造成的次生地质灾害亟需引起注意。Abstract: At 12:52 on September 5, 2022, a MS6.8 earthquake occurred in Luding County, Garze Prefecture, Sichuan Province. The earthquake caused severe damage and heavy casualties in Luding County and its surrounding areas. In order to reproduce the ground motion influence field of the earthquake and analyze the spatial distribution characteristics of near-field ground motion, the deterministic asperity source model is combined with the random source model to obtain the kinematic hybrid source model. Then, the hybrid source model is developed into the SPECFEM 3D, and the whole-process broadband (0.1−5 Hz) ground motion simulation based on the spectral element method and kinematic hybrid source model is realized. Firstly, the simulation results are compared with the time history records of six stations, the corresponding response spectra and the NGA-West2 ground motion attenuation curves to test the applicability of the method. Secondly, the three-component velocity wave field snapshots of the earthquake is given to reproduce the directional effect and local site effect of the near field when the seismic wave propagates. Finally, the peak acceleration (PGA) and peak velocity (PGV) maps of the ground motion in the range of 100 km centered on the Luding area are given, and the spatial distribution characteristics of the ground motion in the near field intensity under the Luding earthquake are analyzed. Based on the simulation results, the seismic intensity distribution map is given. The results show that the epicenter PGA and PGV is close to 600 cm/s2 and 50 cm/s, respectively, and the seismic intensity reaches Ⅸ degree. Due to the influence of mountain-canyon topography in Luding area on the ground motion, the peak of ground motion is significantly amplified at the top of the mountain and the bottom of the canyon, and the amplification of PGA and PGV at the top of the mountain is 1.9 times and 1.5 times, respectively. The amplification of PGA and PGV at the bottom of the canyon is 1.7 times and 1.4 times. Attention should be paid to the phenomenon of earthquake amplification and possible secondary geological disasters in mountain-canyon region.
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图 1 2022年泸定地震震中和震源机制解(中国地震台网中心,2022)及周边地区断裂带分布(Ma et al,2022)
Figure 1. The epicentral location and mechanism solution of the 2022 Luding earthquake (China Earthquake Networks Center,2022) and the distribution of the fault zones around Luding (Ma et al,2022)
表 1 确定性大尺度宽频带地震动模拟实例
Table 1. Large-scale broadband ground motion simulation methods based on deterministic method
模拟方法 自由度数
或单元数网格尺寸
/m模型尺寸/km 模拟频率 模拟区域 参考文献 长 宽 高 间断伽辽金法 960亿 10 兰德斯,丹麦 Heinecke et al (2014) 有限差分法 23.4 万亿 8 147.84 140.4 58 18 唐山,中国 Fu et al (2017) 有限差分法 259亿 12.5 120 80 35 5 加利福尼亚,美国 Rodgers et al (2019) 有限差分法 2030亿 6.25 120 80 30 10 北加利福尼亚,美国 Rodgers et al (2020) 有限差分法 25 102 88 31 10 加利福尼亚,美国 Pitarka et al (2021) 有限差分法 单元数量
(150,486,336,000)8 147.84 140.4 58 5 加利福尼亚,美国 Hu et al (2022) 谱元法 135亿 35—130 44 44 63 10 阿尔戈斯托利,希腊 Touhami et al (2022) 表 2 2022年泸定MS6.8地震断层全局震源参数(中国地震台网中心,2022)
Table 2. Global parameters of Luding MS6.8 earthquake fault (China Earthquake Networks Center,2022)
走向/° 倾角/° 滑动角/° 破裂面长度/km 破裂面宽度/km 破裂起始深度/km 343 79 9 28 13 15.5 表 3 泸定地震断层局部震源参数
Table 3. Local parameters of Luding earthquake fault
局部参数 单位 定标律* 参数值 最大
凹凸体面积Sm km2 lgSm=lgS-0.80 57 平均错动量${\overline D_m}$ cm ${\lg {\overline D_m}=\lg{\overline D}+0.38}$ 206.5 长度Lm km lgLm=lgL-0.48 9.5 宽度Wm km Wm=Sm/Lm 6 沿走向中心Xm km lgXm=lgL-0.32 13.5 沿倾向中心Ym km lgYm=lgW-0.35 6 其它
凹凸体面积Sm0 km2 lgSm=lgS-1.15 24.75 平均错动量${\overline D_{m0}}$ cm ${\lg {\overline D_m}=\lg{\overline D}+0.31} $ 175.8 长度Lm0 km lgLm=lgL-0.69 5.5 宽度Wm0 km Wm=Sm/Lm 4.5 沿走向中心X0 km X0=0.44(L-Xm-0.5Lm)+Xm+0.5Lm 22.5 沿倾向中心Y0 km lgYm=lgW-0.43 5 -
国家市场监督管理总局, 中国国家标准化管理委员会. 2020. GB/T 17742—2020中国地震烈度表[S]. 北京: 中国标准出版社: 8–10. State Administration of Market Supervision and Administration, China National Standardization Management Committee. 2020. GB/T 17742−2020 The Chinese Seismic Intensity Standard[S]. Beijing: Standards Press of China: 8–10 (in Chinese). 曹泽林. 2020. 基于FK法的三分量宽频带强地震动场合成[D]. 哈尔滨: 哈尔滨工业大学: 37–58. Cao Z L. 2020. Synthesis of Three-Component Broadband Strong Ground Motion Field Based on FK Approach[D]. Harbin: Harbin Institute of Technology: 37–58 (in Chinese). 姜伟,陶夏新,陶正如,曹泽林,王立媛. 2017. 有限断层震源模型局部参数定标律[J]. 地震工程与工程振动,37(6):23–30. doi: 10.13197/j.eeev.2017.06.23.jiangw.003 Jiang W,Tao X X,Tao Z R,Cao Z L,Wang L Y. 2017. Scaling laws of local parameters of finite fault source model[J]. Earthquake Engineering and Engineering Dynamics,37(6):23–30 (in Chinese). 李孝波,薄景山,齐文浩,王熠琛,阮璠. 2014. 地震动模拟中的谱元法[J]. 地球物理学进展,29(5):2029–2039. Li X B,BO J S,QI W H,Wang Y C,Ruan F. 2014. Spectral element method in seismic ground motion simulation[J]. Progress in Geophysics,29(5):2029–2039 (in Chinese). 李建有,石宝文,徐晓雅,胡家富. 2018. 利用远震接收函数探测四川盆地及周边地区的地壳结构[J]. 地球物理学报,61(7):2719–2735. Li J Y,Shi B W,Xu X Y,Hu J F. 2018. Crustal structure beneath the Sichuan basin and adjacent region revealed by teleseismic receiver functions[J]. Chinese Journal of Geophysics,61(7):2719–2735 (in Chinese). 李传友,孙凯,马骏,李俊杰,梁明剑,房立华. 2022. 四川泸定6.8级地震:鲜水河断裂带磨西段局部发起、全段参与的一次复杂事件[J]. 地震地质,44(6):1648–1666. Li C Y,Sun K,Ma J,Li J J,Liang M J,Fang L H. 2022. The 2022 M6.8 Luding earthquake:A complicated event by faulting of the Moxi segment of the Xianshuihe fault zone[J]. Seismology and Geology,44(6):1648–1666 (in Chinese). 孙晓丹,陶夏新. 2012. 宽频带地震动混合模拟方法综述[J]. 地震学报,34(4):571–577. doi: 10.3969/j.issn.0253-3782.2012.04.013 Sun X D,TAO X X. 2012. Hybrid simulation of broadband ground motion:Overview[J]. Acta Seismologica Sinica,34(4):571–577 (in Chinese). 铁永波,张宪政,卢佳燕,梁京涛,王东辉,马志刚,李宗亮,鲁拓,石胜伟,刘民生,巴仁基,何龙江,张新克,甘伟,陈凯,高延超,白永健,龚凌枫,曾孝文,徐伟. 2022. 四川省泸定县MS6.8级地震地质灾害发育规律与减灾对策[J]. 水文地质工程地质,49(6):1–12. Tie Y B,Zhang X Z,Lu J Y,Liang J T,Wang D H,Ma Z G,Li Z L,Lu T,Shi S W,Liu M S,Ba R J,He L J,Zhang X K,Gan W,Chen K,Gao Y C,Bai Y J,Gong L F,Zeng X W,Chen W. 2022. Characteristics of geological hazards and it’s mitigations of the MS6.8 earthquake in Luding county,Sichuan Province[J]. Hydrogeology &Engineering Geology,49(6):1–12 (in Chinese). 王海云. 2004. 近场强地震动预测的有限断层震源模型[D]. 哈尔滨: 中国地震局工程力学研究所: 39–62. Wang H Y. 2004. Finite Fault Source Model for Predicting Near-field Strong Ground Motion[D]. Harbin: Institute of Engineering Mechanics, China Earthquake Administration: 39–62 (in Chinese). 闻学泽. 2000. 四川西部鲜水河—安宁河—则木河断裂带的地震破裂分段特征[J]. 地震地质,22(3):239–249. doi: 10.3969/j.issn.0253-4967.2000.03.005 Wen X Z. 2000. Character of rupture segmentation of Xianshuihe-Anninghe-Zemuhe fault zone,western Sichuan[J]. Seismology and Geology,22(3):239–249 (in Chinese). 谢志南,章旭斌. 2017. 弱形式时域完美匹配层[J]. 地球物理学报,60(10):3823–3831. doi: 10.6038/cjg20171012 Xie Z N,Zhang X B. 2017. Weak-form time-domain perfectly matched layer[J]. Chinese Journal of Geophysics,60(10):3823–3831 (in Chinese). 应急管理部. 2022. 应急管理部发布四川泸定6.8级地震烈度图[EB/OL]. [2022-09-11]. https://www.mem.gov.cn/xw/yjglbgzdt/202209/t20220911_422190.shtml. 中国地震台网中心. 2022. 中国地震台网中心震源机制解[EB/OL]. [2022-09-06]. https://data.earthquake.cn/20220905cmt/info/2022/334669342.html. China Earthquake Networks Center. 2022. Focal mechanism solution of China Earthquake Networks Center[EB/OL]. [2022-09-06]. https://data.earthquake.cn/20220905cmt/info/2022/334669342.html (in Chinese). 中国新闻网. 2022. 2022年9月5日四川泸定地震遇难人数[EB/OL]. [2022-09-11]. https://www.chinanews.com.cn/gn/2022/09/11/9848234.shtml. China news.com. 2022. The number of victims of the earthquake in Luding, Sichuan Province, Sept 5, 2022[EB/OL]. [2022-09-11]. https://www.chinanews.com.cn/gn/2022/09/11/9848234.shtml. Andrews D J. 1981. A stochastic fault model:2. Time-dependent case[J]. J Geophys Res,86(B11):10821–10834. doi: 10.1029/JB086iB11p10821 Day S M, Bradley C R. 2001. Memory-efficient simulation of anelastic wave propagation[J]. Bull Seismol Soc Am, 91(3): 520–531. Dangkua D T,Rong Y,Magistrale H. 2018. Evaluation of NGA-West2 and Chinese ground-motion prediction equations for developing seismic hazard maps of mainland China[J]. Bull Seismol Soc Am,108(5A):2422–2443. doi: 10.1785/0120170186 Fu H H, He C H, Chen B W, Yin Z K, Zhang Z G, Zhang W Q, Zhang T J, Xue W, Liu W G, Yin W W, Yang G W, Chen X F. 2017. Nonlinear earthquake simulation on Sunway TaihuLight: Enabling depiction of 18-Hz and 8-meter scenarios[C]//Proceedings of The International Conference for High Performance Computing. New York, NY: 1–2. Graves R W,Pitarka A. 2010. Broadband ground-motion simulation using a hybrid approach[J]. Bull Seismol Soc Am,00(5A):2095–2123. Graves R W,Pitarka A. 2015. Refinements to the Graves and Pitarka (2010) broadband ground-motion simulation method[J]. Seismol Res Lett,86(1):75–80. doi: 10.1785/0220140101 Haskell N A. 1964. Total energy and energy spectral density of elastic wave radiation from propagating faults[J]. Bull Seismol Soc Am,54(6A):1811–1841. doi: 10.1785/BSSA05406A1811 Heinecke A, Breuer A, Rettenberger S, Bader M, Gabriel A A, Pelties C, Bode A, Barth W, Liao X K, Vaidyanathan K, Smelyanskiy M, Dubey P. 2014. Petascale high order dynamic rupture earthquake simulations on heterogeneous supercomputers[C]//Proceedings of the International Conference for High Performance Computing, Networking, Storage and Analysis (SC '14). IEEE: 3–14. Hu Z F,Olsen K B,Day S M. 2022. 0–5 Hz deterministic 3-D ground motion simulations for the 2014 La Habra,California,earthquake[J]. Geophys J Int,230(3):2162–2182. doi: 10.1093/gji/ggac174 Irikura K,Miyake H. 2011. Recipe for predicting strong ground motion from crustal earthquake scenarios[J]. Pure Appl Geophys,168:85–104. Ma J, Zhou B G, Wang M M, Guo P, Liu J R, Ha G H, Fan J. 2022. Surface rupture and slip distribution along the Zheduotang fault in the Kangding section of the Xianshuihe fault zone[J]. Lithosphere, (Special 2): 6500707. Mai P M,Beroza G C. 2002. A spatial random field model to characterize complexity in earthquake slip[J]. J Geophys Res,107(B11):10–21. Pitarka A,Akinci A,Gori D P,Buttinelli M. 2021. Deterministic 3D ground‐motion simulations (0−5 Hz) and surface topography effects of the 30 October 2016 MW6.5 Norcia,Italy earthquake[J]. Bull Seismol Soc Am,112(1):262–286. Rodgers A J,Petersson N A,Pitarka A,McCallen D B,Sjogreen B,Abrahamson N. 2019. Broadband (0−5 Hz) fully deterministic 3D ground-motion simulations of a magnitude 7.0 Hayward fault earthquake:Comparison with empirical ground-motion models and 3D path and site effects from source normalized intensities[J]. Seismol Res Lett,90(3):1268–1284. Rodgers A J,Pitarka A,Pankajakshan R,Sjögreen B,Petersson N A. 2020. Regional-scale 3D ground-motion simulations of MW7 earthquakes on the Hayward Fault,northern California resolving frequencies 0—10 Hz and including site‐response corrections[J]. Bull Seismol Soc Am,110(6):2862–2881. doi: 10.1785/0120200147 Touhami S,Gatti F,Lopez-Caballero F,Cottereau F,Corrêa A L,Aubry L,Clouteau D. 2022. SEM3D:A 3D high-fidelity numerical earthquake simulator for broadband (0−10 Hz) seismic response prediction at a regional scale[J]. Geosci J,12(3):112. doi: 10.3390/geosciences12030112 Wang M,Shen Z. 2020. Present day crustal deformation of continental china derived from GPS and its tectonic implications[J]. J Geophys Res:Solid Earth,125(2):2019JB018774. Wen X Z,Ma S L,Xu X W,He Y N. 2008. Historical pattern and behavior of earthquake ruptures along the eastern boundary of the Sichuan-Yunnan faulted-block,southwestern China[J]. Phys Earth Planet Inter,168(1/2):16–36. -