摘要
在归纳1954年山丹71/4级地震已有地震史料的基础上,根据新获得的朱允明(2006)《山丹地震考察笔记》的详细考察资料,按照《新中国地震烈度表》重新评定了本次地震中各考察点的地震烈度,重新绘制了该地震的等震线图。其中,极震区Ⅸ—Ⅹ度区长轴方向为北西向,呈扁椭圆形,长轴直径约40km;Ⅷ度区南西侧为山丹盆地,第四纪沉积较厚,地震烈度衰减缓慢,因此,Ⅷ度区等震线向南明显突出。1954年山丹71/4级地震极震区位于龙首山北缘断裂西段,大致与该断裂的包代河-黑头山段相吻合,综合分析认为,该段断裂是本次地震的主发震断层,而破喇嘛顶西缘断裂和毛湖洞断裂是重要的参与断裂。
Based on the ＂Seismic Intensity Scale of China＂,the seismic intensity of Shandan 71/4 earthquake in 1954 is re-evaluated,and the earthquake isoseismal line graph is redrawn.After detailed study of the historical records of Shandan 71/4 earthquake in 1954,as well as the newly acquired,detailed investigative data of Zhu Yunming（2006） ＂the investigative notes of Shandan Earthquake＂.In our new isoseismal map,the meizoseismal area（Ⅸ—Ⅹ degree） appears flat oval,with long axis diameter of about 40km with NW direction.The Quaternary sedimentary in Shandan basin is relatively thick,which makes the isoseismal line of Ⅷ degree is extrusive to south obviously.The epicenter area of Shandan 71/4 earthquake in 1954 is located in western section of the Longshoushan northern margin fault,roughly in line with Baodai river—Heitou Mountain segment of this fault.The comprehensive analysis indicates that this fault is the main causative fault of Shandan 71/4 earthquake,while Polamading western margin fault and Maohudong Fault are also involved in and play important roles in the occurrence of the earthquake.
出处
《震灾防御技术》
2010年第2期185-198,共14页
Technology for Earthquake Disaster Prevention
基金
国家自然科学基金(40872132)
甘肃省地震局青年地震科学基金(2009259)资助 中国地震局兰州地震研究所论著号:LC2010022
关键词
1954年山丹71/4级地震
地震史料
等震线
发震构造
Shandan MS71/4 earthquake in 1954
Historical earthquake records
Isoseismal line
Causative structure
