摘要
从阿克塞西红崖子向东经肃北至红柳峡口长约 150km的范围内 ,通过沟、脊位错的分级与相关阶地年龄测试分析 ,将第四纪以来的水系位错量分为 8级 ,并分别给出其形成年龄 ,得到各时段的断裂滑动速率介于 4 .7～ 6.7mm/a ,平均值 6.0mm /a,局部段落某个时段内最高滑动速率值7.7mm/a。位错量与滑动速率的空间分布有中间大、两头小的特点 ,这可能表明破裂从中间向两端发展的过程 ;在时间上 ,上新世以来的滑动速率比其它各个时段都大 ,这可能与青藏地块在距今 5Ma以来的快速隆升及大规模挤出运动相关。资料表明 ,断裂破裂有从主体断裂某一段落扩展到邻近地带 。
Based on the gradation of stream and ridge offset and the dating of terrace sediments in a distance of 150km from Hongyaza in the west of Akesai eastward to Subei and Hongliuxiakou, the river offsets in Quaternary can be divided into 8 grades and their formation dates are acquired. The fault slip rates in different segments range 4.7～6.7mm/a. The average value is 6.0mm/a. As to the local section in a short period, the maximum slip rate can be 7.7mm/a. The distribution of offsets and slip rates shows that they are large at the middle and small at the ends, which may demonstrates that rupture initiates from the middle and develops towards the ends. The slip rate in Pliocene is larger than other epoches, which may be related to the quick lifting of Qinghai Tibetan block since 5Ma B.P. and the large scale of escaping. Data show that fault rupture begins at the main fault, then extends to the vicinity and goes back the main fault.
出处
《地震地质》
EI
CSCD
北大核心
2000年第2期129-138,共10页
Seismology and Geology
基金
国家自然科学基金资助! ( 4 9672 14 9)
关键词
水系位错
滑动速率
阿尔金断裂
断裂带
第四纪
Altun Tagh, River offset and slip rate, Temporal spatial distribution
