Three years of GPS measurements during 1997 - 1999, were used to derive velocity vectors, principal components of total strains, and elastic stresses around northern part of the Nasser Lake, Egypt. Estimated horizontal velocity vectors in ITRF96 are in the range of 31.17 11 mm/yr in N 6o 5o W. The Least-Squares prediction (LSP) technique was employed to segregate the signal and noise in the obtained velocity vectors. Obtained signals (displacement vectors) were differentiated in space to reconstruct the total strains. Then, inelastic strains of the studied area were calculated using the inversion technique developed by El-Fiky (2000). Finally, the rates of crustal stresses at the surface were estimated based on the simple elastic theory. The results of this study indicate that the studied region deforms mostly elastically. There is a compressional strains/stresses regime in the northwestern part of the region. The rate of maximum shear stress reached 0.16 Mpa/yr. The area along the Kalabsha fault has a low plasticity and stresses rates. This might be due to the frequent release of strain/stress energy in the frequent seismic activity along the Kalabsha fault. |
