Present-day crustal motion in northeast China determined from GPS measurements

Abstract

Abstract GPS measurements carried out between 1997 and 2005 at 37 stations distributed throughout northeast China place indicate the presence of constraints on the present-day crustal motion in this region. Velocity vectors relative to Eurasia are very small, only 1.58 mm/yr on average, indicating that the region is generally stable. With the exception of five stations that show significant motion at the 95% confidence level, the insignificant motion of most stations precludes a clear association of their velocities with the rotation of a separate rigid microplate, suggesting that northeast China belongs to Eurasia plate. The velocities of several stations in the southwestern corner of the studied region consistently point to the southeast. This is most probably a distant effect of the eastward motion of northern Tibet. Small velocities of the stations of around the time of the 1999 M W = 7.1 and 2002 M W = 7.3 deep-focus earthquakes, which occurred in Wangqing county, suggest that these earthquakes did not cause wide-spread deformations to the shallow crust.