摘要
2022年1月8日发生的门源M6.9地震诱发了崩塌、滑坡、砂土液化、地裂缝等多种同震地质灾害。通过对门源M6.9地震地质灾害进行现场调查,得出了地质灾害的分布特征和各类型地质灾害的主要特点,分析了地震地质灾害不发育的原因,并对地震地质灾害的长期效应进行了分析预测。研究结果表明:门源地震诱发地质灾害主要分布在震中附近;崩塌、落石总体规模较小,滑坡多为岩质滑坡,且以冰碛物和表层岩土体的溜滑为主。受表层土体冻结和孔隙水压力消散的影响,饱和砂土液化沿较窄的地裂缝呈串珠状分布,喷出物多为粉细砂。地震形成了4条左旋左阶斜列的地表破裂带,并在极震区内形成了大量的地裂缝。断层破碎带对地震动的阻隔作用、覆盖层薄、地表土冻结可能是造成本次地震地质灾害总体不发育的主要原因;地震产生的大量地裂缝导致斜坡和堆积体的稳定性减弱,在耦合集中降雨、冻融作用等因素后可能诱发滑坡灾害,松散堆积于沟床处的崩滑物作为物源,可能会增加地震影响区泥石流灾害的风险。
The Menyuan M6.9 earthquake occurred on January 8,2022,induced many kinds of co-seismic geo-hazards,i.e.,collapses,landslides,sand liquefaction,and ground fissures.Based on the field investigation results,the distribution and characteristics of various types of geological disasters induced by the M6.9 earthquake were obtained in this paper.Besides,the reasons for the undeveloped seismic geo-hazards were analyzed,and the long-term effects of seismic geo-hazards were predicted.The results showed that the geo-hazards induced by the M6.9 earthquake are mainly distributed near the epicenter.The collapses and rockfalls are not big.Most of the landslides are rock landslides,which are dominated by the sliding of moraine and surface rock and soil.Due to the freezing of surface soil and the dissipation of pore water pressure,the liquefaction of saturated sand is beaded along narrow ground fissures,and the ejecta is mostly silty and fine sand.Four sinistral oblique surface rapture zones and a large number of ground fissures are formed in the meizoseismal area.The barrier effect of fault fracture zone on strong motion,thin overburden layer,and freezing of surface soil may cause the undevelopment of seismic geo-hazards.A large number of ground fissures generated by the earthquake weaken the stability of slopes and accumulation bodies,which may induce landslides under the coupling action of concentrated rainfall and freezing-thawing cycles.In addition,loose deposits in gully beds generated by collapses and landslides may increase the risk of debris flow in earthquake-affected areas.
作者
王谦
钟秀梅
高中南
马金莲
万秀红
杨义煊
刘岸果
WANG Qian;ZHONG Xiumei;GAO Zhongnan;MA Jinlian;WAN Xiuhong;YANG Yixuan;LIU Anguo(Key Laboratory of Loess Earthquake Engineering of China Earthquake Agency & Gansu Province, Lanzhou 730000, Gansu, China;Gansu Earthquake Agency, Lanzhou 730000, Gansu, China;Qinghai Earthquake Agency, Xining 750000, Qinghai, China)
出处
《地震工程学报》
CSCD
北大核心
2022年第2期352-359,共8页
China Earthquake Engineering Journal
基金
地震科技星火计划项目(XH21034,XH20057)
甘肃省地震局创新团队项目(TD2020-01-01)
国家自然科学基金项目(51778590)。
关键词
崩塌
滑坡
砂土液化
地裂缝
长期效应
collapse
landslide
sand liquefaction
ground fissure
long-term effect
作者简介
第一作者:王谦(1985-),男,硕士生导师,副研究员,主要从事黄土动力学与黄土地震工程研究,E-mail:wangq0930@126.com;通信作者:钟秀梅(1981-),女,硕士生导师,高级工程师,主要从事黄土动力学与黄土地震工程研究,E-mail:xmzhong26@163.com。
