Kinematic study at the junction of the East Anatolian fault and the Dead Sea fault from GPS measurements

Abstract

The Hatay Triple Junction (HTJ) is a tectonically complex area located at the intersection between the left-lateral East Anatolian fault (EAF), the Cyprus subduction arc and the left-lateral Dead Sea fault (DSF) which is a transform boundary between the Arabian and Sinai plates as they converge toward Eurasia. Previous GPS studies indicate a left-lateral strike-slip rate across the DSF varying from 5mm/yr (along the southern part) to 2mm/yr (along the northern part) (Alchalbi et al., 2010; Gomez et al., 2007; Le Béon et al., 2008; Mahmoud et al., 2005; Al-Tarazi et al., 2011). In contrast, the EAF has a roughly constant velocity along strike estimated at 9.7+0.9mm/yr (Reilinger et al., 2006). The HTJ contains several well-identified active fault segments (DSF, EAF, Osmaniye fault, Karasu fault, Latakia fault, Jisr-al-shuggur fault, Idleb fault and Afrin fault) (Meghraoui et al., 2011), the fault-slip rates for which are poorly constrained.In order to constrain better the slip rate on faults, we established a network of 57 GPS sites in NW Syria and in SE Turkey. The first campaign was carried out in September 2009; a second took place in September and November 2010 and a third (only in Turkey) in September 2011. Although the velocity field vectors computed from the 2009, 2010 and 2011 measurements appear consistent with other local studies, the results are hampered by large uncertainties due to the short observation period. However, preliminary interpretations are consistent with decreasing velocity along the DSF from south to north reported previously.