MOMENT TENSOR INVERSION AND SEISMOGENIC STRUCTURE OF THE 2023 MS5.5 PINGYUAN EARTHQUAKE

doi:10.3969/j.issn.0253-4967.2025.01.017

Abstract

Abstract:

On August 6, 2023, an earthquake with M_S5.5 occurred in Pingyuan County, Dezhou City, in Shandong Province, North China. Around the epicenter of the M_S5.5 Pingyuan earthquake, obvious earthquake tremors were felt through the regions of Hebei, Henan, Tianjin, Beijing etc. This earthquake also broke the historical record of no earthquake with M≥5.0 within 50km of the epicenter and aroused widespread concern of the society and seismologists. It is urgent to carry out the research on strong earthquake seismogenic structures and seismogenic environments in the basin, which is of great significance to strengthen the seismic tectonic environment exploration and earthquake damage prevention in the weak and rare earthquake areas of the North China Plain. Based on the data of the Regional Seismic Networks around the epicenter, moment tensor solution and centroid depth of the M_S5.5 Pingyuan earthquake were determined using the gCAP inversion method, and the stability of moment tensor inversion of the mainshock is evaluated by Bootstrap method. The M_L≥1.0 earthquakes of the M_S5.5 Pingyuan earthquake sequence were relocated using the double-difference relocation method. By simulation method of the relationship between regional stress regime and focal mechanism, the relative shear stress and normal stress of nodal planes from focal mechanism of the M_S5.5 Pingyuan earthquake were obtained. According to the earthquake relocation, the fault plane was fitted, and the seismogenic structure of the earthquake was analyzed. The results indicate: 1)The scalar seismic moment(M₀)of the M_S5.5 Pingyuan earthquake is 1.97Í10¹⁷N·m, while the moment magnitude is M_W5.5, and the centroid depth is 16km. The moment tensor solution(M_rr/M_tt/M_pp/M_rt/M_rp/M_tp)is -0.129/1.194/-0.459/0.009/0.336/0.245, while the double-couple(DC), isotropic(ISO) and compensated linear vector dipole(CLVD) components account for 92.40%, 6.25%, and 1.35% of the full moment tensor solution. The focal mechanism of the double-couple solution shows that the M_S5.5 Pingyuan earthquake is a strike-slip type natural earthquake event with a little normal fault component, with strike/dip/rake of 222°/71°/-156° and 124°/67°/-21° for nodal planes Ⅰ and Ⅱ. The P-axis azimuth is 84° with plunge angle of 30°, indicating the principal compressive stress in the NEE direction in the focal area, basically consistent with the direction of the main compressive stress of the regional tectonic stress in the North China Plain. The best double-couple solutions of focal mechanism obtained by the Bootstrap method are: strike 220.4°±2.49°, dip 71.5°±4.34°, rake -155.9°±3.58° for the nodal plane Ⅰ, and strike 122.2°±2.83°, dip 67.3°±3.17°, rake -20.2°±4.95° for nodal plane Ⅱ, and centroid depth 16.7±1.10km, reflecting the stability and reliability of moment tensor inversion in this paper. 2)After earthquake relocation, the epicenters of the M_S5.5 Pingyuan earthquake sequence mainly show a dominant distribution in the NE-SW direction, with a length of about 15km and a width of about 5km. The epicenter of the M_S5.5 Pingyuan earthquake is located in the southwest segment of the earthquake sequence, and the epicenters of the M_L≥1.0 earthquake are relatively concentrated on the NE side of the main earthquake, while the distribution of the epicenters of the SW side is relatively sparse. The focal depths of earthquakes with M_L≥1.0 are mainly between 8 and 22km, with an average depth of 15.4km. The focal depth profiles demonstrate the fault plane with a dip to the northwest. 3)The regional stress field of North China Craton primarily exhibits NEE-SWW compression and near N-S tensile. The main stress axis direction of the regional stress field is basically consistent with the P-axis of the focal mechanism of the M_S5.5 Pingyuan earthquake. The strike-slip component of the focal mechanism of the M_S5.5 Pingyuan earthquake shows general consistency with the focal mechanism characteristics of the eastern North China Craton. It is also consistent with the E-W compressive and S-N tensile tectonic stress background of the eastern part of the North China Craton, and the small normal components may be related to the tensile movement of the central and western region of Bohai Bay Basin. The relationship between the focal mechanism and contemporary regional stress regime shows the relative shear stress of 0.860/0.689 for nodal planes I and II under the stress field of the Pingyuan region, and the rake of shear stress for the nodal plane I is close to the rake of focal mechanism. The shear stress on nodal plane I of the focal mechanism is relatively high, reflecting that nodal plane I is very close to the fault shape of the optimal release of relative shear stress of the regional stress field, presenting the source property of right-lateral strike-slip with a small amount of normal component. The fault plane fitting also exhibits the mode of fault movement with right-lateral strike-slip. 4)Combined with the previous studies, it is inferred that the nodal plane I of the focal mechanism for the M_S5.5 Pingyuan mainshock is the possible seismic source fault with a dip angle of 71°, and the main seismogenic structure of the Pingyuan earthquake sequence may be a SW-striking blind fault with steep dip to northwest. Under the long-term contemporary principal compressive stress of the tectonic stress field in North China Plain, the M_S5.5 Pingyuan earthquake occurred as a right-lateral strike-slip seismic dislocation with a little normal fault component due to the rupture on the nodal plane with optimum shear stress release. It is suggested that the seismogenic structure of the Pingyuan earthquake may be related to the Lingxian-Guanxian fault, a hidden fault system formed by the northern section of the Guanxian fault and the southern section of the Lingxian-Yangxin fault.

Key words: M_S5.5 Pingyuan earthquake, moment tensor inversion, earthquake relocation, relative shear stress, seismogenic structure

摘要： 2023年8月6日山东省德州市平原县发生 M_S5.5 地震, 震中周边河北、河南、天津及北京等多地震感明显, 该地震打破了震中50km范围内无M≥5.0地震的历史记录, 并引起了社会和地震工作者的广泛关注。基于震中周边的区域地震台网地震资料, 文中采用gCAP方法反演了平原 M_S5.5 地震的矩张量解, 利用双差定位方法对平原 M_S5.5 地震序列中M_L≥1.0的地震进行了重定位, 基于震源机制与区域应力场的数值关系模拟方法计算了平原 M_S5.5 地震震源机制节面的相对剪应力和正应力, 根据重定位结果拟合了断层面, 并分析了该平原地震序列的发震构造。结果显示: 1)平原 M_S5.5 地震的地震矩(M₀)为1.97Í10¹⁷N·m、矩震级为 M_W5.5, 矩心深度16km, 矩张量解M_rr、M_tt、M_pp、M_rt、M_rp、M_tp分别为-0.129、1.194、-0.459、0.009、0.336、0.245, 其最佳双力偶(DC)、各向同性(ISO)、补偿线性向量偶极(CLVD)成分占全矩张量解的92.40%、6.25%、1.35%, 最佳双力偶解的节面Ⅰ的走向、倾角、滑动角分别为222°、71°、-156°, 节面Ⅱ的走向、倾角、滑动角为124°、67°、-21°, P轴方位84°、倾伏角为30°, 显示该地震为走滑型天然地震事件且略带少量的正断分量, 震源区主压应力呈现近NEE-SWW向的推挤特征, 这与华北平原的区域应力场主压应力方向基本一致。2)重定位后的平原 M_S5.5 地震序列震中主要呈NE-SW向优势展布, 长约15km、宽约5km, M_L≥1.0地震的震源深度主要集中在8~22km之间, 平均深度为15.4km, 震源深度剖面显示可能的发震构造倾向NW。3)现今应力场与震源机制数值关系模拟显示, 平原地区的应力体系在平原 M_S5.5 地震震源机制节面Ⅰ和节面Ⅱ产生的相对剪应力分别为0.860和0.689。断层面拟合揭示平原地震发震断层具有右旋走滑的运动性质。4)结合已有研究分析认为, 平原 M_S5.5 地震的震源机制节面Ⅰ为其可能的发震破裂面, 主震发震断层倾角为71°, 地震序列主要发震构造为走向SW、倾向NW的高倾角隐伏断层, 平原 M_S5.5 地震是由于华北平原NEE-SWW向区域应力场主压应力的作用下, 应力得到了充分积累, 在剪应力的最优释放节面破裂引起的一次略具正断分量的右旋走滑型地震事件。

关键词: 平原M_S5.5地震, 矩张量反演, 重定位, 相对剪应力, 发震构造

XU Ying-cai, GUO Xiang-yun. MOMENT TENSOR INVERSION AND SEISMOGENIC STRUCTURE OF THE 2023 M_S5.5 PINGYUAN EARTHQUAKE[J]. SEISMOLOGY AND GEOLOGY, 2025, 47(1): 284-305.

许英才, 郭祥云. 2023年平原M_S5.5地震矩张量反演及发震构造[J]. 地震地质, 2025, 47(1): 284-305.

Figures/Tables 17

Fig. 1 The tectonics and historical earthquakes with MS≥5.0 around the epicenter of the MS5.5 Pingyuan earthquake.

Fig. 2 M-T and daily frequency diagram of the MS5.5 Pingyuan earthquake sequence.

Table 1 1-D velocity model for the Pingyuan region

层号	1	2	3	4	5	6	7
顶层深度H/km	0	5	10	15	20	25	35
V_P/km·s^-1	4.86	5.55	5.68	6.02	6.35	6.95	7.67
波速比k	1.71

Fig. 3 Variation of fitting error with depth during the moment tensor inversion of the MS5.5 Pingyuan earthquake.

Fig. 4 Comparison between the observed(black)and synthetic(red)waveforms at the best fitting depth of the MS5.5 Pingyuan earthquake.

Fig. 5 Focal mechanism solutions of the MS5.5 Pingyuan earthquake by Bootstrap method in 1 000 times.

Table 2 Components of the full moment tensor solution from the MS5.5 Pingyuan earthquake

2023年8月6日平原M_S5.5地震	ζ	χ	Λ^DC/%	Λ^CLVD/%	Λ^ISO/%
本文结果1(18个波形最佳台站)	0.25	-0.12	92.40	1.35	6.25
本文结果2(Bootstrap平均解)	0.24	-0.13	92.65	1.59	5.76

Fig. 6 Comparison of focal mechanism of the MS5.5 Pingyuan earthquake from different sources.

Table 3 The nodal planes, P, T and B axes parameters of focal mechanisms of the MS5.5 Pingyuan earthquake from different sources

来源	节面Ⅰ/(°)			节面Ⅱ/(°)			P轴/(°)		T轴/(°)		B轴/(°)		最小旋转角 /(°)
来源	走向	倾角	滑动角	走向	倾角	滑动角	方位角	倾伏角	方位角	倾伏角	方位角	倾伏角
本文结果1	222	71	-156	124	67	-21	84	30	352	2	258	60	1.41
本文结果2	220	72	-156	122	67	-20	82	29	350	3	255	60	2.16
张喆等	224	72	-161	128	72	-19	86	26	356	0	266	64	5.25
地球所	220	67	-156	120	68	-25	80	33	170	1	261	57	5.66
NEIC	224	66	-154	123	66	-26	83	35	173	0	264	55	6.60
CENC	225	69	-150	123	62	-24	86	36	353	4	257	54	7.37
预测所	226	75	-149	127	60	-17	90	32	354	10	249	56	8.38
韩立波等	221	71	-148	120	60	-22	83	36	348	7	249	53	8.94
GFZ	220	76	-166	127	76	-14	83	20	173	0	264	70	9.51
郭祥云等	232	71	-153	133	65	-21	94	32	1	4	265	57	9.85
CPPT	209	86	-174	119	84	-4	74	7	344	1	243	83	23.78

Fig. 7 Simulation on the relationship between regional stress regime and focal mechanism of the MS5.5 Pingyuan earthquake.

Fig. 8 Relative shear stress, P-axis, regional principal compressive stress and dislocation mode of two nodal planes from focal mechanism forthe MS5.5 Pingyuan earthquake.

Table 4 Relative shear stress and normal stress on the two nodal planes of the focal mechanism solution of the MS5.5 Pingyuan earthquake

平原M_S5.5地震的震源机制	相对剪应力	相对正应力	剪应力的滑动角/(°)	震源机制的滑动角/(°)	剪应力滑动角方向与震源机制滑动角方向之间的夹角/(°)
节面Ⅰ	0.860	0.543	164.4	-156	39.6
节面Ⅱ	0.689	-0.293	-3.7	-21	17.3

Fig. 9 Relocated epicenters of the MS5.5 Pingyuan earthquake sequence.

Fig. 10 Cross-sections of AA' and BB' for the MS5.5 Pingyuan earthquake sequence.

Fig. 11 Fault plane fitting of the MS5.5 Pingyuan earthquake sequence.

Table 5 Parameters of the fitting fault from the relocated Pingyuan earthquake sequence

地震序列拟合断层面或主震震源机制节面	走向/(°)	倾角/(°)	滑动角/(°)	运动性质
平原M_S5.5地震序列重定位结果拟合的断层面	248	75	-139	右旋走滑兼正断
平原M_S5.5地震震源机制节面Ⅰ	222	71	-156	右旋走滑
平原M_S5.5地震震源机制节面Ⅱ	124	67	-21	左旋走滑

Fig. 12 Seismogenic structure of the MS5.5 Pingyuan earthquake.

References 52

[1]	陈国光, 徐杰, 高战武. 2003. 华北渤海湾盆地大震的构造特征[J]. 华北地震科学, 21(2): 7—15.
	CHEN Guo-guang, XU Jie, GAO Zhan-wu. 2003. Seismotectonic features of the Bohai Bay Basin in North China[J]. North China Earthquake Sciences, 21(2): 7—15 (in Chinese).
[2]	崔华伟, 郑建常, 张正帅, 等. 2020. 长岛地区小地震断层面参数拟合及应力场特征[J]. 地震地质, 42(6): 1432—1445. doi: 10.3969/j.issn.0253-4967.2020.06.011.
	CUI Hua-wei, ZHENG Jian-chang, ZHANG Zheng-shuai, et al. 2020. Fitting the fault plane parameters with small earthquakes and the characteristics of stress field of Changdao area[J]. Seismology and Geology, 42(6): 1432—1445 (in Chinese).
[3]	邓起东, 冉勇康, 杨晓平, 等. 2007. 中国活动构造图(1︰400万)[CM]. 北京: 地震出版社.
	DENG Qi-dong, RAN Yong-kang, YANG Xiao-ping, et al. 2007. Distribution of Active Faults in China[CM]. Seismological Press, Beijing (in Chinese).
[4]	董腾超, 李腾. 2018. 德州市城区地震构造环境和地震活动性分析[J]. 智能城市, 4(23): 54—56.
	DONG Teng-chao, LI Teng. 2018. Analysis of seismic tectonic environment and seismicity in Dezhou City[J]. Intelligent City, 4(23): 54—56 (in Chinese).
[5]	房立华, 吴建平, 苏金蓉, 等. 2018. 四川九寨沟 M_S7.0 地震主震及其余震序列精定位[J]. 科学通报, 63(7): 649—662.
	FANG Li-hua, WU Jian-ping, SU Jin-rong, et al. 2018. Relocation of mainshock and aftershock sequence of the 7.0 Sichuan Jiuzhaigou earthquake[J]. Chinese Science Bulletin, 63(7): 649—662 (in Chinese).
[6]	葛粲, 郑勇, 熊熊. 2011. 华北地区地壳厚度与泊松比研究[J]. 地球物理学报, 54(10): 2538—2548.
	GE Can, ZHENG Yong, XIONG Xiong. 2011. Study of crustal thickness and Poisson ratio of the North China craton[J]. Chinese Journal of Geophysics, 54(10): 2538—2548 (in Chinese).
[7]	胡惟. 2014. 郯庐断裂带渤海段新构造活动方式与深部背景[D]. 合肥: 合肥工业大学.
	HU Wei. 2014. Neotectonics active modes and deep background of the Bohai segment of the Tan-Lu fault zone[D]. Hefei University of Technology, Hefei (in Chinese).
[8]	蒋海昆, 曲延军, 李永莉, 等. 2006. 中国大陆中强地震余震序列的部分统计特征[J]. 地球物理学报, 49(4): 1110—1117.
	JIANG Hai-kun, QU Yan-jun, LI Yong-li, et al. 2006. Some statistic features of aftershock sequences in Chinese mainland[J]. Chinese Journal of Geophysic, 49(4): 1110—1117 (in Chinese).
[9]	姜磊, 丁志峰, 高天扬, 等. 2021. 利用背景噪声和接收函数研究华北克拉通地壳结构[J]. 地球物理学报, 64(5): 1585—1596.
	JIANG Lei, DING Zhi-feng, GAO Tian-yang, et al. 2021. Crustal structure beneath the North China Craton from joint inversion of ambient noise and receiver function[J]. Chinese Journal of Geophysics, 64(5): 1585—1596 (in Chinese).
[10]	姜在兴, 肖尚斌. 1999. 渤海湾盆地第三系火成岩的分布规律[J]. 地质论评, 45(增刊): 618—626.
	JIANG Zai-xing, XIAO Shang-bin. 1999. Distribution pattern of Tertiary igneous rocks in the Bohai Bay Basin[J]. Geological Review, 45(S1): 618—626 (in Chinese).
[11]	李理, 赵利, 刘海剑, 等. 2015. 渤海湾盆地晚中生代一新生代伸展和走滑构造及深部背景[J]. 地质科学, 50(2): 446—472.
	LI Li, ZHAO Li, LIU Hai-jian, et al. 2015. Late Mesozoic to Cenozoic extension and strike slip structures and deep background of Bohai Bay Basin[J]. Chinese Journal of Geology, 50(2): 446—472 (in Chinese).
[12]	李理, 钟大赉, 杨长春, 等. 2008. 渤海湾盆地济阳坳陷滑脱构造研究[J]. 地球物理学报, 51(2): 521—530.
	LI Li, ZHONG Da-lai, YANG Chang-chun, et al. 2008. The décollement structures in Jiyang Depression, Bohai Bay Basin, China[J]. Chinese Journal of Geophysics, 51(2): 521—530 (in Chinese).
[13]	林向东, 袁怀玉, 徐平, 等. 2017. 华北地区地震震源机制分区特征[J]. 地球物理学报, 60(12): 4589—4622.
	LIN Xiang-dong, YUAN Huan-yu, XU Ping, et al. 2017. Zonational characteristics of earthquake focal mechanism solutions in North China[J]. Chinese Journal of Geophysics, 60(12): 4589—4622 (in Chinese).
[14]	刘白云, 赵莉, 刘云云, 等. 2023. 2021年5月22日青海玛多M7.4地震余震重新定位与断层面参数拟合[J]. 地震地质, 45(2): 500—516. doi: 10.3969/j.issn.0253-4967.2023.02.012.
	LIU Bai-yun, ZHAO Li, LIU Yun-yun, et al. 2023. The research on relocation and fault plane solution and geometric meaning of the Maduo M7.4 earthquake on 22 May 2021[J]. Seismology and Geology, 45(2): 500—516 (in Chinese).
[15]	彭远黔, 冉志杰, 朱坤静. 2021. 冠县断裂展布及其第四纪活动性研究[J]. 华北地震科学, 39(3): 38—44.
	PENG Yuan-qian, RAN Zhi-jie, ZHU Kun-jing. 2021. Distribution of Guan County fault and its Quaternary activity[J]. North China Earthquake Sciences, 39(3): 38—44 (in Chinese).
[16]	Seismology小组. 2023. 2023年8月6日山东德州发生5.5级地震的震源机制中心解及其产生的位移场和形变场[EB/OL]. https://mp.weixin.qq.com/s/0TiarPlCHzEGkXL8R3V2og. 2023-08-08].
	Seismology Group. 2023. The central focal mechanism solution of the M5.5 Dezhou earthquake on August 6, 2023, in Shandong Province and its displacement and strain fields[EB/OL]. https://mp.weixin.qq.com/s/0TiarPlCHzEGkXL8R3V2og. 2023-08-08]
[17]	申金超, 李士成, 张斌. 2018. 鲁西隆起和济阳拗陷耦合关系分析[J]. 地质与资源, 27(5): 411—416.
	SHEN Jin-chao, LI Shi-cheng, ZHANG Bin. 2018. Analysis on the coupling relationship between Luxi uplift and Jiyang depression in western Shandong Province[J]. Geology and Resources, 27(5): 411—416 (in Chinese).
[18]	万永革. 2016. 地震学导论[M]. 北京: 科学出版社:393—395.
	WAN Yong-ge. 2016. Introduction to Seismology[M]. Science Press, Beijing: 393—395 (in Chinese).
[19]	万永革. 2019. 同一地震多个震源机制中心解的确定[J]. 地球物理学报, 62(12): 4718—4728.
	WAN Yong-ge. 2019. Determination of center of several focal mechanisms of the same earthquake[J]. Chinese Journal of Geophysics, 62(12): 4718—4728 (in Chinese).
[20]	万永革. 2020. 震源机制与应力体系关系模拟研究[J]. 地球物理学报, 63(6): 2281—2296.
	WAN Yong-ge. 2020. Simulation on the relationship between stress regimes and focal mechanisms of earthquakes[J]. Chinese Journal of Geophysics, 63(6): 2281—2296 (in Chinese).
[21]	万永革, 沈正康, 刁桂苓, 等. 2008. 利用小震分布和区域应力场确定大震断层面参数方法研究及其在唐山地震序列中的应用[J]. 地球物理学报, 51(3): 793—804.
	WAN Yong-ge, SHEN Zheng-kang, DIAO Gui-ling, et al. 2008. An algorithm of fault parameter determination using distribution of small earthquakes and parameters of regional stress field and its application to Tangshan earthquake sequence[J]. Chinese Journal of Geophysics, 51(3): 793—804 (in Chinese).
[22]	王辉, 曹建玲, 申旭辉. 2011. 华北地区的背景地震活动及区域未来强震危险性[J]. 地震, 31(2): 11—23.
	WANG Hui, CAO Jian-ling, SHEN Xu-hui. 2011. Background seismicity and its application to seismic hazard assessment in the north China region[J]. Earthquake, 31(2): 11—23 (in Chinese).
[23]	王纪祥, 陈发景, 李趁义. 2003. 山东惠民凹陷伸展构造及调节带特征[J]. 现代地质, 17(2): 203—209.
	WANG Ji-xiang, CHEN Fa-jing, LI Chen-yi. 2003. Character of the extensional structures and accommodation zones in the Huimin depression, Shandong Province[J]. Geoscience, 17(2): 203—209 (in Chinese).
[24]	王书宝, 钟建华, 陈志鹏. 2007. 惠民凹陷新生代断裂活动特征研究[J]. 地质力学学报, 13(1): 86—96.
	WANG Shu-bao, ZHONG Jian-hua, CHEN Zhi-peng. 2007. Characteristics of Cenozoic fault activities in the Huimin subbasin[J]. Journal of Geomechanics, 13(1): 86—96 (in Chinese).
[25]	王霞, 宋美琴, 陈慧. 2019. 华北地区地震空区的统计分析[J]. 地震, 39(3): 187—195.
	WANG Xia, SONG Mei-qin, CHEN Hui. 2019. Statistical analysis of seismic gap in north China[J]. Earthquake, 39(3): 187—195 (in Chinese).
[26]	王晓山, 冯向东, 赵英萍. 2020. 京津冀地区地壳应力场特征[J]. 地震研究, 43(4): 610—619.
	WANG Xiao-shan, FENG Xiang-dong, ZHAO Ying-ping. 2020. Characteristics of crustal stress field in Beijing-Tianjin-Hebei region[J]. Journal of Seismological Research, 43(4): 610—619 (in Chinese).
[27]	武岩, 丁志峰, 王兴臣, 等. 2018. 华北克拉通地壳结构及动力学机制分析[J]. 地球物理学报, 61(7): 2705—2718.
	WU Yan, DING Zhi-feng, WANG Xing-chen, et al. 2018. Crustal structure and geodynamics of the North China Craton derived from a receiver function analysis of seismic wave data[J]. Chinese Journal of Geophysics, 61(7): 2705—2718 (in Chinese).
[28]	许鑫, 万永革, 冯淦, 等. 2022. 安徽霍山地区丛集地震事件揭示的3条地震断面及其滑动性质研究[J]. 地球物理学报, 65(5): 1688—1700.
	XU Xin, WAN Yong-ge, FENG Gan, et al. 2022. Study on three seismic fault segments and their sliding properties revealed by clustered seismic events in Huoshan area, Anhui Province[J]. Chinese Journal of Geophysics, 65(5): 1688—1700 (in Chinese).
[29]	于平, 杨冬, 杨宝俊. 2003. 华北地台聊城-兰考断裂地球物理场基本特征及其构造意义[J]. 吉林大学学报(地球科学版), 33(1): 106—110.
	YU Ping, YANG Dong, YANG Bao-jun. 2003. The basic character of geophysical field and the tectonic significance of Liaocheng-Lankao Fault in northern China platform[J]. Journal of Jilin University(Earth Science Edition), 33(1): 106—110 (in Chinese).
[30]	张广伟, 雷建设. 2015. 2015尼泊尔 M_S8.1 地震中等余震震源机制研究[J]. 地球物理学报, 58(11): 4298—4304.
	ZHANG Guang-wei, LEI Jian-she. 2015. Focal mechanism solutions of moderate-sized aftershocks of the 2015 M_S8.1 Nepal earthquake[J]. Chinese Journal of Geophysics, 58(11): 4298—4304 (in Chinese).
[31]	赵利, 李理. 2016. 渤海湾盆地晚中生代以来伸展模式及动力学机制[J]. 中国地质, 43(2): 470—485.
	ZHAO Li, LI Li. 2016. The extensional pattern and dynamics of Bohai Bay Basin in Late Mesozoic-Cenozoic[J]. Geology in China, 43(2): 470—485 (in Chinese).
[32]	中国地震局. 2023. 中国地震局发布山东平原5.5级地震烈度图[EB/OL]. [2023-08-08]. https://www.cea.gov.cn/cea/xwzx/365134/5736905/index.html.
	China Earthquake Administration. 2023. The China Earthquake Administration released the seismic intensity map of M5.5 Pingyuan earthquake in Shandong Province[EB/OL].[2023-08-08]. https://www.cea.gov.cn/cea/xwzx/365134/5736905/index.html. in Chinese).
[33]	中国地震局地球物理研究所. 2023a. 2023年8月6日山东德州市平原县5.5级地震科技支撑简报[EB/OL]. [2023-08-06]. https://www.cea-igp.ac.cn/kydt/280165.html.
	Institute of Geophysics, China Earthquake Administration. 2023a. Science and technology support brief of the M5.5 earthquake in Pingyuan County, Dezhou City, Shandong Province, August 6, 2023[EB/OL]. [2023-08-06]. https://www.cea-igp.ac.cn/kydt/280165.html in Chinese).
[34]	中国地震局地球物理研究所. 2023b. 2023年8月6日山东德州市平原县5.5级地震科技支撑简报(Ⅱ)[EB/OL]. [2023-08-08]. https://www.cea-igp.ac.cn/kydt/280185.html.
	Institute of Geophysics, China Earthquake Administration. 2023b. Science and technology support brief of the M5.5 earthquake in Pingyuan County, Dezhou City, Shandong Province, August 6, 2023(Ⅱ)[EB/OL]. [2023-08-08]. https://www.cea-igp.ac.cn/kydt/280185.html in Chinese).
[35]	中国地震局地球物理研究所. 2023c. 地球所牵头国家重点研发计划项目支撑2023年山东平原5.5级地震研究[EB/OL]. [2023-08-08]. https://www.cea-igp.ac.cn/kydt/280184.html.
	Institute of Geophysics, China Earthquake Administration. 2023c. National Key Research and Development Program of China led by Institute of Geophysics, China Earthquake Administration supports the research of the 2023 M5.5 Pingyuan earthquake in Shandong Province[EB/OL]. [2023-08-08]. https://www.cea-igp.ac.cn/kydt/280184.html in Chinese).
[36]	中国地震台网中心. 2023. 中国地震台网-首页[DB/OL]. [2023-08-06]. https://news.ceic.ac.cn/.
	China Earthquake Networks Center. 2023. China Earthquake Networks Center-Home Page[DB/OL]. [2023-08-06]. https://news.ceic.ac.cn/ in Chinese).
[37]	朱日祥, 陈凌, 吴福元, 等. 2011. 华北克拉通破坏的时间、范围与机制[J]. 中国科学(地球科学), 41(5): 583—592.
	ZHU Ri-xiang, CHEN Ling, WU Fu-yuan, et al. 2011. Timing, scale, and mechanism of the destruction of the North China Craton[J]. Science China(Earth Sciences), 54(6): 789—797.
[38]	Efron B, Tibshirani R. 1986. Bootstrap methods for standard errors, confidence intervals, and other measures of statistical accuracy[J]. Statistical Science, 1(1): 54—77.
[39]	European-Mediterranean Seismological Centre. 2023. EMSC-European-Mediterranean Seismological Centre[DB/OL].[2023-08-06]. https://www.emsc-csem.org/.
[40]	Lei X L, Wang Z W, Su J R. 2019. Possible link between long-term and short-term water injections and earthquakes in salt mine and shale gas site in Changning, south Sichuan Basin, China[J]. Earth and Planetary Physics, 3(6): 510—525.
[41]	Long F, Zhang Z W, Qi Y P, et al. 2020. Three dimensional velocity structure and accurate earthquake location in Changning-Gongxian area of southeast Sichuan[J]. Earth and Planetary Physics, 4(2): 163—177.
[42]	Waldhauser F, Ellsworth W L. 2000. A Double-difference earthquake location algorithm: Method and application to the northern Hayward fault, California[J]. Bulletin of the Seismological Society of America, 90(6): 1353—1368.
[43]	Wan Y G. 2010. Contemporary tectonic stress field in China[J]. Earthquake Science, 23(4): 377—386.
[44]	Wang Q C, Zhang J C, Wang Z P, et al. 2021. Spatiotemporal evolution of the 2021 M_S6.4 Yangbi earthquake sequence[J]. Earthquake Science, 34(5): 413—424.
[45]	Xin H L, Zhang H J, Kang M, et al. 2019. High-resolution lithospheric velocity structure of continental China by double-difference seismic travel-time tomography[J]. Seismological Research Letters, 90(1): 229—241.
[46]	Xu J, Gao Z W, Song C Q. 2001. Newly generated seismotectonic zones in North China and its regional seismotectonic framework[J]. Scientia Geologica Sinica, 10(3): 159—168.
[47]	Zhang Z, Xu L S, Fang L H. 2024. The M_W5.5 earthquake on August 6, 2023, in Pingyuan, Shandong, China: A rupture on a buried fault[J]. Earthquake Science, 37(1): 1—12.
[48]	Zhao L S, Helmberger D V. 1994. Source estimation from broadband regional seismograms[J]. Bulletin of the Seismological Society of America, 84(1): 91—104.
[49]	Zhu L P, Ben-Zion Y. 2013. Parametrization of general seismic potency and moment tensors for source inversion of seismic waveform data[J]. Geophysical Journal International, 194(2): 839—843.
[50]	Zhu L P, Helmberger D V. 1996. Advancement in source estimation techniques using broadband regional seismograms[J]. Bulletin of the Seismological Society of America, 86(5): 1634—1641.
[51]	Zhu L P, Rivera L A. 2002. A note on the dynamic and static displacements from a point source in multilayered media[J]. Geophysical Journal International, 148(3): 619—627.
[52]	Zhu L P, Zhou X F. 2016. Seismic moment tensor inversion using 3D velocity model and its application to the 2013 Lushan earthquake sequence[J]. Physics and Chemistry of the Earth, Parts A/B/C, 95: 10—18.