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| Titel |
Preliminary geologic slip rates of the Ovacik Segment (Malatya-Ovacik Fault, Turkey) for the last 15 ka: Insights from cosmogenic 36Cl dating of offset fluvial surfaces |
| VerfasserIn |
Cengiz Zabcı, Taylan Sançar, Dimitry Tikhomirov, Christof Vockenhuber, Susan Ivy-Ochs, Naki Akçar |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094357
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| Publikation (Nr.) |
 EGU/EGU2014-9761.pdf |
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| Zusammenfassung |
| Continental plate boundaries are often displayed as broadly deforming regions by parallel or
sub-parallel fault systems. Understanding the behavior and interactions of the individual
faults provide invaluable data not only to figure out the role of each fault sets in
accommodation of the relative plate motion, but also to reveal the seismic potential of
the region. Contradictory to the diffused deformation zones, the strain is mainly
localized along the North Anatolian (NAF) and the East Anatolian (EAF) faults
at the boundaries of the Anatolian Block. However, recent geodetic studies show
considerable magnitude of strain accumulation higher than the previous expectations along
the Malatya-Ovacik Fault (MOF), which is located parallel or sub-parallel with a
changing distance from 40 km to 100 km to the EAF. Elastic block model slip-rates
change from 1.2 to 1.8 mm/a, which are exceeded with almost factor of 7 to 8 by the
modeled velocities of the EAF (~10 mm/a). Understanding both the quantitative
slip partitioning and the temporal behavior of these two fault zones at the eastern
boundary of the Anatolian block will provide very important data not only for this
particular region, but also for plate boundaries where the deformation are broadly
distributed.
In order to find answer for some of the questions raised above, we started to study the
northeastern section, the Ovacik Segment, of the MOF, where faulting is clearly observed
along well-preserved fault scarps, pressure ridges, and, offset alluvial fans and inset terraces.
In order to reconstruct the chronology of the fan and inset terrace surfaces we collected
samples for cosmogenic 36Cl dating at the Köseler site (Ovacik, Tunceli). In addition, we
performed rtk-GPS survey for precise offset measurements of the terrace risers. Our
preliminary analyses show that at the eastern banks, the boundary between the Alluvial fan
and the inner channel is displaced for 30±5 m. In addition to that, we also measured 19±3 m
sinistral offset on the terrace riser, bounding the upper alluvial fan and the lower
inset terrace treads at the western banks. Preliminary 36Cl results from upper and
lower treads yielded exposure ages of ca. 16 and 12 ka, respectively. Based on
these, we calculated two independent geologic slip rates, 1.9 and 1.6 mm/a, which
represent close but higher values than the block model based geodetic velocities. Our
results from this study play an important role both in understanding of the temporal
relationship of the MOF and the EAF and the seismic risk assessment of the region. |
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