Publication Date:
2000
Description:
Three multichannel seismic profiles imaged a normal fault to at least 10 km
depth in the North Aegean Trough and Thermai:kos basin. The fault is active and recent,
forming a scarp at sea bottom and crossing the Quaternary deltaic front on the northern
slope of the trough controlled to the south by the North Anatolian fault. Prestack depth
migration imaged the fault as a seismic reflector cutting steeply across the sedimentary
rocks and flattening in the basement. From the seismic image, the N100E strike of the
fault scarp, and the orientations of the three profiles, the true fault dip is
constrained to an average 20degree in the basement, a low-angle dip. The throw and age
estimated from the geometry in the sedimentary rocks document recent onset of the motion
that must have occurred at a high rate. Both the direction and the rate of slip are
consistent with the instantaneous motion as measured by space-based geodesy, which shows
the fault to be forming by pure normal slip. Large earthquakes that have occurred in the
basin may relate to such normal faults, whereas the North Anatolian fault with its
current strike-slip earthquakes appears to slip here under low resolved shear stress.
Keywords:
Crustal deformation (cf. Earthquake precursor: deformation or strain)
;
Deep seismic sounding (espec. cont. crust)
;
Sea seismics
;
Geodesy
;
Reflection seismics
;
NAF
;
Greece
;
Fault zone
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