摘要
公元849年10月20日(唐宣宗大中三年十月辛巳),在内蒙古包头附近发生了一次大地震,造成城堡、军营和民房破坏等严重震害和数千人死亡。目前对本次地震的震中位置、烈度和震级等基本参数认识尚存疑。通过对相关史料的系统梳理,重点对位置存疑的云伽关或云伽镇等进行进一步分析论证,重新核定了主要破坏地点及其地震烈度,修绘了地震等震线图,校核了地震震级、震中位置等基本参数。结果表明,公元849年地震等震线呈不对称的纺锤形,长轴方向为近东西向,短轴呈近南北向,极震区烈度可达X~X+度,震中位置大约在今内蒙古包头市附近,即40.6°N、110.3°E,震级达(7.8±0.3)级或7级。其中,等震线南侧地震影响范围大(包括河套盆地及其以南较大区域)、震害重、烈度衰减慢,而北侧几乎无震害记载,地震烈度衰减快,影响范围小。本次地震烈度等震线属于典型的正断层地震类型,其发震构造为大青山山前断裂中西段。文章依据历史地震史料校核结果与前人基于活动断裂研究结果所确定的震中位置和震级大致相当。综合研究认为鄂尔多斯北缘发生的公元849年地震震级约为7级,该区未来地震震级上限及其大震风险值得继续深入研究。
On October 20,849 A.D.(October of the third year of Dazhong,Emperor Xuanzong of Tang),a great earthquake occurred near Baotou City,Inner Mongolia Autonomous Region,causing serious destruction of castles,military camps,and civilian houses and thousands of deaths.At present,the basic parameters of this earthquake(e.g.,epicenter location,intensity,and magnitude)are controversial.In this work,the relevant historical records were systematically integrated.Further discussion was performed on the seriously affected towns,such as Yunjia Pass or Yunjia Town,because their locations were inconclusive.In addition,the earthquake intensity and locations of the main damaged places were reevaluated,the isoseismal map of the earthquake was modified,and the basic parameters such as earthquake magnitude and epicenter location were corrected.Results show that the isoseismal line of the earthquake in 849 A.D.is asymmetrically spindle-shaped,with its long axis in a nearly east-west direction and its short axis in a nearly north-south direction.The seismic intensity in the meizoseismal area can reach X-X+degrees.The epicenter is located near Baotou City,Inner Mongolia(40.6°N,110.3°E),with a magnitude of about 7.8±0.3 or 73/4.On the south side of the isoseismal line,the earthquake has affected a large area(including Hetao Basin and its south area),with heavy earthquake damage and slow attenuation of seismic intensity.On the north side,almost no earthquake damage has been reported.Correspondingly,the attenuation of seismic intensity is fast,and the affected area is quite small.The isoseismal line shows that this earthquake belongs to a typical normal faulting earthquake,and the seismogenic structure is the middle-western segment of the Daqingshan piedmont fault.Our results on the epicenter location and earthquake magnitude,which are based on historical earthquake data,are consistent with previous findings based on active faults.This study indicates that the earthquake in 849 A.D.,which occurred in the northern margin of Ordos,has a ma
作者
袁道阳
雷中生
司国军
刘兴旺
于锦超
李红强
陈艳文
孙浩
张梨君
YUAN Daoyang;LEI Zhongsheng;SI Guojun;LIU Xingwang;YU Jinchao;LI Hongqiang;CHEN Yanwen;SUN Hao;ZHANG Lijun(School of Earth Sciences,Lanzhou University,Lanzhou 730000,Gansu,China;Gansu Earthquake Agency,Lanzhou 730000,Gansu,China)
出处
《地震工程学报》
CSCD
北大核心
2023年第3期501-512,共12页
China Earthquake Engineering Journal
基金
第二次青藏高原综合科学考察研究(2019QZKK0901)
国家自然科学基金(42172227,41572197)
国家重点研发计划专项(2017YFC1500101)。
关键词
公元849年内蒙古包头地震
历史地震
发震构造
大青山山前断裂
Baotou,Inner Mongolia earthquake in 849 A.D.
historical earthquake
seismogenic structure
Daqingshan piedmont fault
