Three-dimensional crustal deformation before and after the Wenchuan earthquake in Guanzhong and adjacent regions

The recent plethora of GPS observations compensates for the 20-year-old lack in vertical displacement data for the Guanzhong region. The 2001–2007 three-dimensional (3D) crustal deformation data suggest regional movement with a horizontal velocity of 3–7 mm/a, predominantly from SSE in the west to SE in the east, and vertical inherited movement with velocity of −7 mm/a to 4 mm/a. After the Wenchuan earthquake, the GPS data suggest that the effect of the earthquake on the regional deformation is greater in the west than the east. The horizontal displacement increased during 2007–2008; however, the reverse was observed in 2008–2009. The vertical displacement in the western part of the region increased in 2008 and has been gradually returning to normal since 2009; however, in the eastern part, the effect of the earthquake remains.