Fagel, Nathalie ; Université de Liège, Département de Géologie, Liege, Belgium
Çagatay, Namik; Istanbul Teknik Universitesi, Faculty of Mines, Istanbul, Turkey
Language :
English
Title :
Earthquake imprints on a lacustrine deltaic system: Example of the Kürk Delta along the East Anatolian Fault (Turkey)
Publication date :
2017
Event name :
EGU Vienna 2017
Event place :
Vienne, Austria
Event date :
23–28 April 2017
Audience :
International
References of the abstract :
Geophysical Research Abstracts, 19.Katlenburg-Lindau, GermanyEuropean Geophysical Society. (2017).
Name of the research project :
QuakeRecNankai project
Funders :
BELSPO - Service Public Fédéral de Programmation Politique scientifique
Commentary :
Deltas contain sedimentary records that are not only indicative of water level changes, but also particularly sensitive
to earthquake shaking typically resulting in soft-sediment-deformation structures. The Kürk lacustrine delta
lies at the south-western extremity of Lake Hazar in eastern Turkey and is adjacent to the seismogenic East Anatolian
Fault (EAF), which has generated earthquakes of magnitude 7. In this paper we have reevaluated water level
changes and earthquake shaking that have affected the Kürk Delta combining geophysical data (seismic-reflection
profiles and side-scan sonar), remote sensing images, historical data, onland outcrops and offshore coring. The history
of water level changes provides a temporal framework for the depositional record. In addition to the common
soft-sediment-deformation documented previously, onland outcrops reveal a record of deformation (fracturing, tilt
and clastic dykes) linked to large earthquake-induced liquefactions and lateral spreading. The recurrent liquefaction
structures can be used to obtain a paleoseismological record. Five event horizons were identified that could
be linked to historical earthquakes occurring in the last 1000 years along the EAF. Sedimentary cores sampling
the most recent subaqueous sedimentation revealed the occurrence of another type of earthquake indicator. Based
on radionuclide dating (137Cs and 210Pb), two major sedimentary events were attributed to the AD 1874-1875
EAF earthquake sequence. Their sedimentological characteristics were determined by X-ray imagery, XRD, LOI,
grain-size distribution and geophysical measurements. The events are interpreted to be hyperpycnal deposits linked
to post-seismic sediment reworking of earthquake-triggered landslides.
