We present a horizontal velocity field determined from a GPS network with 22 sites surveyed from 2001 to 2012 in northwestern Vietnam. The velocity is accurately estimated at each site by fitting a linear trend to each coordinate time series, after accounting for coseismic displacements caused by the 2004 Sumatra and the 2011 Tohoku earthquakes using static fault models. Considering the coseismic effects of the earthquakes, the motion of northwestern Vietnam is 34.3 ± 0.7 mm/yr at an azimuth of N108• ± 0.7• E in ITRF2008. This motion is close to, but slightly different from, that of the South China block. The area is in a transition zone between this block, the Sundaland block, and the Baoshan sub-block. At the local scale, a detailed estimation of the crustal deformation across major fault zones is geodetically revealed for the first time. We identify a locking depth of 15.3 ± 9.8 km with an accumulating left-lateral slip rate of 1.8 ± 0.3 mm/yr for the Dien Bien Phu fault, and a shallow locking depth with a right-lateral slip rate of 1.0 ± 0.6 mm/yr for the Son La and Da River faults.

This paper presents velocities of present-day tectonic movement and strain rate in the East Vietnam Sea (South China Sea) and surroundings determined from GPS campaigns between 2007 and 2010. We determine absolute velocities of GPS stations in the ITRF05 frame. The result indicates that GPS stations in the North of East Vietnam Sea move eastwards with the slip

Crustal movement along the Red River Fault zone from GNSS data For the first time, recent crustal movement of the Red River Fault was investigated, discussed by segments, based on GNSS data of Thac Ba, Ba Vi-Tam Dao, and Ha Noi networks. Data acquired by the network were processed, movement characteristics of fault zones were synthesized and evaluated and results were achieved, (1) absolute crustal movement velocities of the study area are approximately 34 mm/year with east-southeast direction, (2) the Red River Fault has been relatively inactive in recent times, with a relative motion between two sides of the fault is approximately 1 mm/year. We propose that more measurement campaigns should be taken in order to determine the value and trend of movements more accurately.

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