Gomez, F., Karam, G., Khawlie, M., McClusky, S., Vernant,
P., Reilinger, R., Jaafar, R., Tabet, C., Khair, K., and Barazangi, M.
Global Positioning System measurements of strain accumulation and slip transfer
through the restraining bend along the Dead Sea fault system in Lebanon
Geophysical Journal International, 168, 1021-1028, 2007.
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 45 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.
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Key Figures and Captions
Figure 2. Map showing general structure of the Lebanese restraining
bend. GPS velocities for the network used in this study are also shown in an
Arabia-fixed reference frame (2-sigma uncertainties). Abbreviations for some
key tectonic features: RF = Roum fault, RaF = Rachaya fault, AF = Akkar fault,
& PFB = Palmyride fold belt. Box denotes the swath encompassed by the profiles
in Figure 3.