Active faults' geometry in the Gulf of Aqaba, southern Dead Sea fault,
illuminated by multi beam bathymetric data
Abstract
Detailed knowledge of fault geometry is important for accurate seismic
hazard assessments. The Gulf of Aqaba, which corresponds to the southern
termination of the 1200-km-long Dead Sea fault system, remains one of
the least known parts of this plate boundary fault, in large part due to
its location offshore. Classically, the Gulf of Aqaba has been described
as a succession of three pull-apart basins. Here, building on a new
multibeam bathymetric survey of the Gulf of Aqaba, we provide details
about the geometry of the faults at the bottom of the gulf that controls
its morphology. In particular, we identify a 50 km-long fault section
that shows evidence of recent activation. We associate this fault
section (Aragonese fault) with the section that ruptured during the 1995
magnitude Mw7.3 Nuweiba earthquake. In the southern part of the gulf,
bathymetry emphasizes the strike-slip nature of the Arnona fault, while
dip-slip motion seems to be accommodated mostly by faults located along
the eastern edge of the gulf. Considering the simple linear geometry of
the Arnona fault and the absence of any large earthquake for several
centuries, despite an average slip-rate of ~5 mm/yr,
this fault should be considered as a significant candidate for an
earthquake rupture of magnitude 7 or above in the near future.