长乐—诏安断裂带闭锁程度和块体运动研究

Fault Locking and Block Movement of Changle—Zhaoan Fault

利用2011—2016年长乐—诏安断裂带周边30个GPS基准站水平速度场数据,采用负位错模型,反演长乐—诏安断裂带滑动速率和闭锁程度;通过比对近年的地震分布,验证反演结果的合理性。反演结果表明,闽东南块体相对于闽东块体呈现左旋运动。长乐—诏安断裂带南段和北段同一深度的闭锁程度整体较中段高。长乐—诏安断裂带南段地表以下5km闭锁程度较高(闭锁比例0.99),北段地表以下10km闭锁程度较高,在25～30km处整条断裂均逐步由闭锁转变为完全蠕滑。上述反演结果与长乐—诏安断裂带周边的历史地震分布范围相符。

In this paper,we use the horizontal velocity field data from 30 GPS seismic monitoring stations around Changle-Zhaoan fault from 2011 to 2016 and a negative dislocation model to invert for the slip rate and fault locking of Changle-Zhaoan fault.In addition,the rationality of the result is tested by comparisons with the earthquake distribution in recent years.The inversion results show that the southeast Fujian block shows left-lateral movement relative to the east Fujian block.The locking fraction of the southern and northern segments of the Changle-Zhaoan fault is higher than that of the middle segment at the same depth.The southern segment is tightly locked from surface to a depth of 5 km(locking fraction is 0.99),and the northern segment is tightly locked from surface to a depth of 10 km,and the fault gradually turns from locking to creeping between 25 km and 30 km.The inversion results are consistent with the distribution of historical earthquakes around the fault.