Crustal motion in E- and SE-Asia from GPS measurements

Repeated GEODYSSEA-GPS measurements and additional GPS data from the IGS an d APRGP97/98 constrain the motion of SE-Asia within a global reference fram e. Sundaland i.e. Indochina as well as the western and central part of Indo nesia, together with South-China, constitute an apparently stable tectonic block that is decoupled from Eurasia. In the ITRF97 this block moves to the east about an Euler pole approximating that of Eurasia, but with a velocit y that is one third higher than the eastward directed movement of Eurasia. With respect to India and Australia the Sundaland-South China block is movi ng due south. This suggests that a) Sundaland-South China are moving cohere ntly to the East along the boundaries studied and b) the eastward motion of India is compensated by the eastward motion of Sundaland-South China. The current rather homogeneous kinematic behaviour of Sundaland-South China tha t differs in rate (no more than 5 mm) rather than direction from the moveme nt of N-China differs from the kinematics proposed by different modelling a pproaches throughout the literature. The data help to constrain locations a nd behaviour of the active fault zones and give information on the interpla te and intraplate deformation in the area.