Research on an intraplate movement model by inversion of GPS data in North China

In this paper, data obtained by the 1995, 1996 and 1999 three GPS campaigns in North China have been used to study intraplate tectonic block movements in this area (N36° -N42°, and E112°-E120°). By a Bayesian inversion method, negative dislocation distributions on three main fault zones and individual relative movements between four intraplate tectonic blocks have been obtained based on these GPS data. The results show that the relative movements between four intraplate tectonic plates are several millimeters per year. The obtained negative dislocation values on the Front Tai-Hong Mountain fault are -5±2 mm/a in tensile component, and 2±2 mm/a in both strike and dip component, which indicates that this fault mainly suffers pull apart tectonic movements. On the Tangshan-Ninghe fault, the obtained negative dislocation values are -3±3 mm/a in dip, -2±2 mm/a in tensile and -1±3 mm/a in strike, which indicates that the east part of this fault still undergoes upward movement. On the Zhangjiako-Beipiao fault, the obtained negative dislocation values are -4±2 mm/a in strike, 0±2 mm/a in dip, and 1±2 mm/a in tensile, which indicates that this fault has sinistral strike movement. According to the inversion results, the southern part of the Zhangjiako-Beipiao fault suffers pull tectonic movements caused by recent upward movement of the eastern part. The pulling tectonic movements are almost totally blocked on the Front Tai-Hong Mountain fault and this fault is more likely to be a potential earthquake source.