摘要
富蕴断裂是阿尔泰地区低应变速率条件下的典型右旋走滑断层之一。野外考察和3个观测点的3D陆地LiDAR扫描DEM影像断错地貌恢复、重建,结合高分辨率卫星影像解译等进一步证实,1931年富蕴地震同震右旋走滑位移平均值为(6.3±1.2)m,且沿富蕴断裂向南北两端缓慢、平稳衰减,中部同震位移最大值为(6.7±0.5)m,而不是前人给出的10～14m;包含2～5次地震的同震累积位移值为1931年富蕴地震相同地点同震位移的整数倍,表明富蕴断裂大地震复发服从特征地震模型。2个观测点多级地貌面宇宙成因核素(10Be)系统测年数据,进一步限定富蕴断裂晚更新世以来的右旋走滑速率为(0.76±0.24)mm/a,大地震复发间隔(9700±3300)a。低滑动速率和长周期特征地震复发模型可能为板块间相互作用产生的远程应变效应的基本特征。
The Fuyun Fault is a typical right-lateral strike-slip fault in Ahay region where the crustal strain rate is very low. Field observations and restoration of horizontal offsets from the 3D LiDAR data ob- tained from 3 sites along the Funyun Fault further confirm that the average coseismic right-lateral slip of the 1931 Fuyun earthquake is （6.3±1.2）m,and the slip distribution is unusually flat over its en- tire length of the Fuyun Fault. The maximum slip is only （6.7±0.5）m under the Karaxingar Range, near to the central part of the surface rupture zone other than 10m to 14m as reported before. Co-loca- ted larger offsets,interpreted as cumulative offsets, allow us to define at least 4 more events in addition to the most recent. The cumulative slip distribution of each event seems to follow a similar flat pat- tern,supporting a characteristic earthquake model interpretation for the 5 last events. Several succes- sive offset landforms are dated at 2 sites by cosmogenic dating method （1~Be）to constrain the long- term right-lateral slip rate of （0.76±0.24）mm/a. An average characteristic slip of 6.3m, a maximum slip of -6.7m and a slip rate of （0.76±0.24）mm/a yield a recurrence interval of （9 700±3 300）a. Then,great earthquakes on the Fuyun Fault,a right-lateral strike-slip fault follow a characteristic slip behavior with a low long-term slip rate and long recurrence interval,which is a faulting response to the far-field strain resulting from the collision between the Indian and Eurasian plates.
出处
《地震地质》
EI
CSCD
北大核心
2012年第4期606-617,共12页
Seismology and Geology
基金
国家自然科学基金(40974057和40821160550)资助
关键词
富蕴断裂
同震右旋走滑位移
特征地震复发模型
阿尔泰地区
Fuyun Fault, coseismic right-lateral strike-slip, characteristic earthquake recurrencemodel, Ahay region
