Subsidence Monitoring in Mashhad and Neyshabour Area based on Change of Curvature Analysis Method Using Displacement Field from GPS Observations

The methodology of geometrical modeling of the earth surface deformation [surface deformation tensor of the first kind (tensor of strain),linearized surface rotation tensor, and surface deformation tensor of the second kind (tensor of change of curvature)] is done using different kind of space geodetic data (VLBI, SLR, GPS, DORIS, Levelling). In this study the tensor of change of curvature and its invariants and the change of the mean and Gaussian curvature in the Lagrangian portrayal was computed using GPS observation to monitor the subsidence of Mashhad and Neyshabour area. For this purpose, coordinates and displacement rates (velocities) of Iranian Permanent GPS Network (Khorasan area) in Eurasian frame derived in 2007 were analyzed. The maximum value of the rate of mean and Gaussian curvature difference are 14×10-14/myr and 4×10-20/myr respectively in study area. The patterns of numerical analysis confirm land subsidence induced by over explosion of ground water in study area.