Geophysical Journal International (2007, v. 168, p. 1021 –
1028)
Global Positioning System measurements of strain accumulation and slip
transfer through the restraining bend along the Dead Sea fault system in
Lebanon
Francisco Gomez1, Gebran Karam2,
Mohamad Khawlie3, Simon McClusky4, Philippe Vernant4,
Robert Reilinger4, Rani Jaafar1, Charles Tabet5,
Kamal Khair6, Muawia Barazangi7
1Department of Geological Sciences, University of Missouri,
Columbia, Missouri 65211
2Department of Civil Engineering, Lebanese American University,
Jbail, Lebanon
3Lebanese National Center for Remote Sensing, Beirut, Lebanon
4Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139
5Lebanese National Council for Scientific Research, Beirut,
Lebanon
6Hasbaya, Lebanon
7Institute for the Study of the Continents, Snee Hall, Cornell
University, Ithaca, New York 14853
Abstract
Approximately four years of campaign and continuous GPS measurements
across the Dead Sea fault system 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 3,000 meters of topography
in the Mount Lebanon and Anti-Lebanon ranges. The GPS velocity field
indicates 4 – 5 mm/yr of relative plate motion is transferred through the
restraining bend to the northern continuation of the Dead Sea fault system
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.
Return to publication list
Return to main page