东昆仑活动断裂带东段古地震活动特征  

PALEO-EARTHQUAKE STUDIES ON THE EASTERN SECTION OF THE KUNLUN FAULT

作　　者：李春峰[1] 贺群禄[2] 赵国光[2] 

机构地区：[1]同济大学海洋地质教育部重点实验室,中国上海200092 [2]中国地震局地壳应力研究所,中国北京100085

出　　处：《地震学报》2005年第1期60-67,共8页Acta Seismologica Sinica

基　　金：中法合作"东昆仑岩石圈缩短机制研究"课题资助.

摘　　要：东昆仑活动断裂托索湖-玛曲以东肯定那一带,可据阿尼玛卿玛积峰为界再分为花石峡段和玛沁段两个在几何上不连续的段落.两段在表征断层全新世活动特征的古地震事件方面有明显差异,花石峡段的地震活动性明显高于玛沁段的地震活动性.古地震研究表明,花石峡段上3次强震活动相邻两次地震发生的时间间隔分别约为500 a和640 a,玛沁段上最近两次古地震事件间大致有1 000 a左右的时间间隔.根据断层平均滑动速率计算的花石峡段7.5级地震的平均复发间隔为411～608 a,相对应的同震平均水平位错约为(5.75±0.57)m.虽然玛沁段的地震活动性较弱,但由于该段上最近一次地震事件离现在较为久远,已经积累的应变能应该使我们对其未来地震危险性的分析有足够重视.Roughly along the Animaqing Maji peak, the Kunlun fault section between the Tuosuo Lake and Kendingna (east Maqin) can be subdivided into two geometric segments: the Huashixia and the Maqin segments. These two segments behave differently in their Holocene slip rates and paleo earthquake activities, with obviously higher paleo seismic activity on the Huashixia segment than on Maqin segment. As many as four strong Holocene earthquakes are identified on the Huashixia segment from trenching and geomorphic studies. The recurrent interval for the latest three earthquakes are at about 500 a and 640 a, respectively. On the Maqin segment, at least three paleo earthquake events can be defined from trenching, with a recurrent interval for the latest two events at about 1 000 a. M =7.5 earthquakes on Huashixia segment recur at every 411 to 608 years with a characteristic slip at 5.75±0.57 m. Although the Maqin segment is less active, its accumulated strain energy during the long time period since last earthquake occurred (about 1 070 a BP) deserves enough notice on its future earthquake probabilities.

关 键 词：昆仑断裂带 全新世滑动速率 古地震 地震复发间隔 强震危险性分析 

分 类 号：P315.5[天文地球—地震学]