GPS Evidence for Northward Motion of the Sinai Block: Implications for E. Mediterranean Tectonics

We present GPS yearly survey-mode observations for the period 1997 to 2003 at 12 sites within and adjacent to the Sinai Peninsula to constrain motion of the Sinai Block. Sites in the Sinai Peninsula show northerly motion relative to Africa (Nubian plate) at an average rate of 1.5 +/- 1 mm/yr north and -0.8 +/- 1 mm/yr west (1 sigma). While there is some variability, 11 of 12 sites show northerly motion strongly suggesting that the Sinai as a whole is moving northward relative to Nubia. Continuous IGS GPS sites in Israel, west of the Dead Sea fault (greater than 45 km from the fault trace and outside the main zone of elastic strain accumulation) show a similar northerly sense of motion relative to Africa (~ 2.7 +/- 1mm/yr north and -0.9 +/- 1 mm/yr west), suggesting that the entire Sinai Block south of Lebanon is characterized by northward translation relative to Africa. Using an elastic block model we estimate slip rates for the Gulf of Aqaba - southern Dead Sea fault system of 5.1 +/- 0.7 mm/yr, left lateral, and along the Gulf of Suez of 3.0 +/- 0.5 mm/yr left lateral. Present-day opening of the Gulf of Suez is less than 1 mm/yr. This block model provides a quantitative, kinematic explanation for the first order, present-day tectonic character of the easternmost Mediterranean, including the Dead Sea fault system, the Gulf of Suez, and the Cyprus Arc.