Abstract:

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.

Key words: Red River fault, GPS, strain accumulation, slip rate