Global Positioning System measurements of strain accumulation and slip transfer through the restraining bend along the Dead Sea fault system in Lebanon

Abstract

Approximately 4 yr of campaign and continuous Global Positioning System (GPS) measurements across the Dead Sea fault system (DSFS) in Lebanon provide direct measurements of interseismic strain accumulation along a 200-km-long restraining bend in this continental transform fault. Late Cenozoic transpression within this restraining bend has maintained more than 3000 m of topography in the Mount Lebanon and Anti-Lebanon ranges. The GPS velocity field indicates 4-5 mm yr(-1) of relative plate motion is transferred through the restraining bend to the northern continuation of the DSFS in northwestern Syria. Near-field GPS velocities are generally parallel to the major, left-lateral strike-slip faults, suggesting that much of the expected convergence across the restraining bend is likely accommodated by different structures beyond the aperture of the GPS network (e.g. offshore Lebanon and, possibly, the Palmyride fold belt in SW Syria). Hence, these geodetic results suggest a partitioning of crustal deformation involving strike-slip displacements in the interior of the restraining bend, and crustal shortening in the outer part of the restraining bend. Within the uncertainties, the GPS-based rates of fault slip compare well with Holocene-averaged estimates of slip along the two principal strike-slip faults: the Yammouneh and Serghaya faults. Of these two faults, more slip occurs on the Yammouneh fault, which constitutes the primary plate boundary structure between the Arabia and Sinai plates. Hence, the Yammouneh fault is the structural linkage that transfers slip to the northern part of the transform in northwestern Syria. From the perspective of the regional earthquake hazard, the Yammouneh fault is presently locked and accumulating interseismic strain

Seismic structure beneath the Gulf of Aqaba and adjacent areas based on the tomographic inversion of regional earthquake data

“…The DST can be traced for more than 1000 km from the Red Sea to the westernmost end of the Zagros collision zone in eastern Turkey; it cuts the continental crust along the eastern margin of the Mediterranean Sea. Global positioning system (GPS) observations provide rates of the present left-lateral displacement along the DST fault in the range of 3.5-4.0 mm per year (Wdowinski et al, 2004;Gomez et al, 2007), but geological data provide evidence for faster rates ranging from 5 to 10 mm per year of long-term displacements in the past starting from the initiation of the DST 20-15 Ma ago (Garfunkel, 1981;Chu and Gordon, 1998). On the basis of geological information, the total displacement in a segment of the DST between the Gulf of Aqaba and the Dead Sea has been estimated to be 105 km (Freund et al, 1968;Bartov et al, 1980;Garfunkel et al, 1981).…”

Early-to-mid Pleistocene Tectonic Transition Across the Eastern Mediterranean Influences the Course of Human History

“…The importance of prehistoric dates in this context is whether they are dated to pre, syn or post tectonic transition. Increasing convergence between the Sinai and Arabian plates along the central and northern segments of the Dead Sea fault (Gomez et al, 2007) during the early Pleistocene, resulted in synchronous structural modifications along the Dead Sea fault axis. Along the northern Dead Sea fault, the Ghab basin subsided continuously during the Plio-Pleistocene (Brew, 2001).…”

“…During the late early Pleistocene the Jisr ash Shugshur basalts (1.3-1.1 Ma; Sharkov et al, 1994) flowed to the northern part of the basin, covering a possible northern transverse faulting (Kopp et al, 1999). A notable phase of transpressive motion, folding and uplift deformed the Syrian coastal ranges and uplifted of the Nahr El-Kabir at the Mediterranean shore of NW Syria during the Pleistocene (Hardenberg and Robertson, 2007); uplifted the Lebanese restraining bend (Dubertret, 1955;Butler et al, 1998;Walley, 1998;Griffiths et al, 2000;Tapponnier et al, 2004;Elias, 2006); and branching developed along the Dead Sea fault Yammunneh main fault (Gomez et al, 2007). However, timing of initiation of the transpressive phase in Lebanon and Syria is often reported to the entire Pliocene -Pleistocene period.…”

The Ruin of the Roman Temple of Kedesh, Israel; Example of a Precariously Balanced Archaeological Structure Used as a Seismoscope

“…Formed in the early Miocene, the DSTF transitions into the opening of the Red Sea (RS) Rift in the south to the Bitlis-Zagros collision zone of Arabia and Eurasia in the north [Quennell 1956, Freund et al 1968. Early Miocene geologic features are offset 105 km [Quennell 1956, Freund 1965, Bartov et al 1980, indicating that the long term sinistral slip rate of 4-6 mm/year is very similar to short term geodetic rate [Wdowinski et al 2004, Gomez et al 2007, Sadeh et al 2012. The DSTF in Israel and Jordan is divided into segments named according to the valleys, from south to north: the Araba Valley (AV), the Jordan Valley ( JV), and the Hula Valley (HV).…”