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| Titel |
The late Quaternary slip history of the North Anatolian Fault, Turkey: Implications for the spatial and temporal behaviour of large strike-slip fault belts |
| VerfasserIn |
Cengiz Zabcı, H. Serdar Akyüz, Taylan Sançar, Nafiye Güneç Kıyak |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250110836
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| Publikation (Nr.) |
 EGU/EGU2015-10876.pdf |
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| Zusammenfassung |
| The study of the spatial and temporal behaviour of active faults by estimating the geologic
and geodetic slip rates is critical not only for assessing the seismic potential of these tectonic
structures, but also for understanding their geodynamics. Geodetic data can provide detailed
spatial coverage but represent a short time interval of a single earthquake cycle, while
geologic rates are derived as average values for multiple events at spatially limited
sites. In the complex tectonic setting of the eastern Mediterranean, the westward
extrusion of the Anatolian scholle is mainly accommodated by two major tectonic
structures, the North Anatolian (NASZ) and the East Anatolian (EASZ) shear zones,
respectively forming the northern and eastern boundaries. The rate of deformation all
along the North Anatolian Fault (NAF) is spatially well documented mainly by GPS
and InSAR based geodetic studies during the last two decades. Furthermore, the
number of the morphochronology-based geologic slip rate studies significantly
increased, covering the different sections of this large strike slip fault for various time
intervals.
In this study, we do not only compile all previous geologic slip rate estimates, but we also
present data for three new and two revised sites from central to the most eastern parts of the
NAF in order to understand the spatial and temporal behaviour of this important fault system.
The integrated dataset of geologic studies were classified into two groups to represent the
central to eastern sections (Model I) and the western part (Model II). The geographical
diversion between two models is about at the 31Ë E longitude, where the NAF bifurcates into
two branches from this point toward west into the Marmara Region. To test any secular
variation in fault’s slip history, we used the Monte Carlo approach of Gold and Cowgill
(2011). After the removal of rates, which do not account the near fault deformation or the
existing parallel/sub-parallel faults, the Model I (central-eastern NAF) yield uniform
slip rates of about 17 and 19 mm/a for the last 11 and 5 ka, respectively. Although
Model II gives a similar uniform rate of about 17 mm/yr for the last 20 ka for the
western NAF, the slip history solution shows secular variations in the very long-term
offset structures of 100ka time scale within the Sea of Marmara, including eras of
deceleration and acceleration during the last 500 ka. The time scale of these changes are
remarkably very longer than the earthquake cycle, but shorter than the time-scale
characteristics of lithospheric-scale dynamics. The most possible explanation can be the
co-dependence between the northern and southern strands of the NASZ that a change on
one strand is matched with an equal or opposite change in the rate on the other. In
order to have a better understanding on this phenomena or the apparent discrepancy
between the geologic and geodetic slip rates, the future studies are mandatory to
increase the spatial and temporal resolution especially along the southern strand in the
Marmara Region, the splay on the central part and the central-east sections of the
NAF.
Keywords: North Anatolian Fault, slip rate, variation in crustal deformation,
Turkey
Reference
Gold, R. D., and E. Cowgill (2011), Deriving fault-slip histories to test for secular
variation in slip, with examples from the Kunlun and Awatere faults, Earth and Planetary
Science Letters, 301(1–2), 52-64, doi:10.1016/j.epsl.2010.10.011. |
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