红河断裂带不同构造区段的现今滑动速率与应变积累状况

利用中国地壳运动监测网络1999年—2015年GPS观测数据, 基于块体模型与弹性半空间下的螺旋位错模型, 反演红河断裂带不同区段的滑动速率与闭锁深度, 利用插值均匀网格法计算红河断裂带不同区段及周边地区应变积累状况。结果表明: 红河断裂带北段右旋走滑速率为4.76±0.78mm?a^-1, 闭锁深度约为10.9km; 中段右旋走滑速率为3.24±0.56mm?a^-1, 闭锁深度约为11.5km; 南段右旋走滑速率为2.83±0.34mm?a^-1, 闭锁深度约为12.6km。红河断裂带北段与中段拉张应变特征明显, 南段挤压应变特征明显, 北段拉张应变值为(20~40)×10^-9?a^-1, 南段挤压应变值为(30~50)×10^-9?a^-1, 中段最大剪应变积累较弱, 量值为(0~30)×10^-9?a^-1, 北段、南段最大剪应变积累较强, 量值为(40~80)×10^-9?a^-1。北段和南段元阳地区出现最大剪应变高值区, 地震危险性较大。

Current slip rate and strain accumulation in different tectonic sections of Red River fault zone

The GPS data from the period of 1999—2015 are part of the project of “Crustal Movement Observation Network of China”. Based on the block model and the spiral dislocation model under elastic half space, the slip rate and locking depth of different Red River fault sections are inversed, and the strain accumulation is calculated by the interpolated uniform grid method. The results indicate that the strike-slip rate and locking depth of Red River fault zone in the northern, central and southern parts are, respectively, about (4.76±0.78) mm?a^-1 and 10.9 km, (3.24±0.56) mm?a^-1 and 11.5 km and (2.83±0.34) mm?a^-1 and 12.6 km. The tension characteristics of the northern and middle sections are obvious, and the extrusion characteristics of the southern section is obvious. The northern part tensile strain value is (20~40)×10^-9?a^-1, and the southern part compressive strain value is (30~50)×10^-9?a^-1. The maximum shear strain accumulation in the middle section is relatively weak, with the value of (0~30)×10^-9?a^-1; the maximum shear strain accumulation in the northern and southern sections are stronger, with the value of (40~80)×10^-9?a^-1. The maximum shear strain high value area appears in the northern and southern sections of Yuanyang, and the earthquake risk there is large.