Displacement pattern of the Sinai area: first results from GPS

A network of 12 GPS stations, seven of them located on the Sinai peninsula, another four on the west shore of the Gulf of Suez and the last on the inner Gulf of Aqaba (ELAT, Israel) was analyzed twice, processing GPS data recorded in November 1997 and in May 1998. A rigorous statistical analysis based on the F (Fisher) test applied on the detected coordinate differences showed significant displacement at all the sites located on the Sinai peninsula with respect to the others. The planar displacements of the Sinai sites are of the order of 1.5 cm in the considered time span. The agreement exhibited by the Sinai displacements, both in magnitude and azimuth, taking into account the associated errors, provides evidence that the Sinai peninsula behaves like a rigid block or sub-plate with respect to the African plate. A raw estimate of its mean velocity gives about 3.0 cm/yr and 208° of azimuth. Although it is not possible to draw exhaustive conclusions on the geodynamics of the Suez and Sinai areas and the lack of GPS data on the Arabian peninsula makes the analysis incomplete, our results agree well with the left lateral motion of the Aqaba-Levant fault. Moreover, no evidence of extension is detected for the Gulf of Suez, but rather unexpectedly, a contraction component seems to be found by the present work.