地质力学学报2025，Vol.31Issue(2)：211-222,12.DOI:10.12090/j.issn.1006-6616.2024114
2023年积石山MS 6.2地震的地震裂缝及其成因机制
Earthquake-induced fissures and their formation mechanisms in the 2023 MS 6.2 Jishishan Earthquake
摘要
Abstract
[Objective]Seismic fissures,landslides and mudflows are common secondary hazards of earthquakes.Following the occurrence of moderately strong earthquakes,detailed investigations of landslides and mudflows are usually conducted,but earthquake-induced fissures often receive less attention,because the characteristics and causes of earthquake-induced fissures are controlled by a combination of factors.The 2023 MS6.2 Jishishan Earthquake formed an extensive and dense earthquake-induced fissure zone in the Jishishan Mountain front and the interior of the Linxia Basin,but there are large differences in the understanding of the genetic mechanisms of earthquake-induced fissures.[Methods]In order to better understand the characteristics and genetic mechanisms of earthquake-induced fissures in the Jishishan Mountains,246 fissures were systematically investigated by field observation,statistical analysis,and drone photogrammetry;then,the distribution,characteristics and genetic mechanisms of the earthquake-induced fissures were analyzed.Combined with relevant published studies,the following new findings are made.[Results]First,the 2023 MS6.2 Jishishan Earthquake formed a large number of fissures in the Ⅶ-Ⅷ degree zone,which can be generally divided into two categories:tectonic-related fissures and non-tectonic fissures,and the non-tectonic fissures are further divided into ridge gravity fissures,landslide-related fissures,and valley fissure-sand liquefaction combinations on the basis of the topography associated with these fissures.Second,the tectonic-related fissures developed along the eastern margin fault of the Jishishan Mountains,with fissure widths at the cm-mm level.The tectonic-related fissures extend through fault planes,joints,and other weaknesses of the Jishishan fault zone,clearly showing that the more than 100 m wide fracture zone(i.e.,weak zone in the upper crust)of the eastern margin fault of the Jishishan Mountains dominates the distribution of the earthquake-induced fissures.Meanwhile,the tectonic-related fissures tend to develop at weaknesses in man-made structures,such as road seams and bridge joints;this"weakening-preferred"behavior indicates that these fissures are generated by seismic shaking effects on the fracture zone along the fault,rather than direct rupture by the earthquake-causing fault.Thus,the tectonic micro-fissures are not the surface ruptures mentioned above.Third,the non-tectonic fissures mainly developed in the loess-covered area around the Dahejia-Kexinmin-Ganhetan villages north of the epicenter,where the topography is hilly,predominantly tableland and valleys;ridge(tableland)gravity fissures are large in scale,extend far along the ridge,and exhibit a combination of reticulation,parallelism,or en echelon style;landslide-related fissures on the slopes are comparatively smaller in scale and confined to the landslide area;valley fissures are comparable in scale to tectonic micro-fissures and generally formed in association with sand liquefaction;the fissure widths decrease from dm scale on the ridges(tableland)to mm scale in the valleys.Fourth,the tectonic-related micro-fissures healed naturally within approximately half a year,while the healing of the ridge gravity fissures lasted much longer;some landslide-related fissures may take a long time to heal naturally and may even form permanent displacements that pose a serious threat to people and require repair.[Conclusion]By reviewing and analyzing the distribution,types,and genetic mechanisms of earthquake-induced fissures in the 2023 MS6.2 Jishishan Earthquake,and taking into account the magnitude,the epicenter depth,and minor surface displacements,it is speculated that no surface ruptures formed during the Jishishan Earthquake.[Significance]An overview of the earthquake-induced fissures of the Jishishan Earthquake is of great significance for understanding the causal mechanisms of secondary earthquake disasters,analyzing seismotectonics,and proposing disaster mitigation strategies.关键词
地震裂缝/积石山地震/积石山东缘断裂/地震地质灾害/地表破裂Key words
earthquake-induced fissures/Jishishan Earthquake/eastern margin fault of Jishishan Mountains/geological hazards of earthquakes/surface rupture分类
天文与地球科学引用本文复制引用
张波,王爱国,姚赟胜,何小龙,姚赛赛,朱俊文,蔡艺萌..2023年积石山MS 6.2地震的地震裂缝及其成因机制[J].地质力学学报,2025,31(2):211-222,12.基金项目
中国地震局地震科技星火计划(XH23040A,XH19045Y) （XH23040A,XH19045Y）
科技部第二次青藏高原综合科学考察研究专题(2019QZKK0901) （2019QZKK0901）
国家自然科学基金项目(42372267,42072246,41602225) （42372267,42072246,41602225）
中国地震局地震预测研究所基本科研业务费专项(2021IESLZ06)This research is finacially supported by the Spark Program of Earthquake Technology of China Earthquake Administration(Grant Nos.XH23040A and XH19045Y),the Second Tibetan Plateau Scientific Expedition and Research Program(STEP),Ministry of Science and Technology(Grant No.2019QZKK0901),the National Natural Science Foundation of China(NSFC)Projects(Grant Nos.42372267,42072246,and 41602225),and the Basic Scientific Research Special Project of the Institute of Earthquake Forecasting,China Earthquake Administration(Grant No.2021IESLZ06). （2021IESLZ06）
