Yazici, Muge; Zabci, Cengiz; Natal'in, Boris A.; Sançar, Taylan; Akyuz, H. Serdar

The Ovacik Fault (OF) is one of the internal structures of the Anatolian Block, located close to its eastern boundary. Although it shows a very clear surface trace, there are no instrumentally recorded surface rupturing earthquakes on this fault. This study concludes results of the first palaeoseismological trench study on the OF with the evidence for three surface rupturing earthquakes for the last 6 kyr. Structural, stratigraphical and geochronological constraints show that the oldest event happened between 4700 and 3022 BCE, whereas the penultimate event was between 2262 and 1643 BCE. The youngest event happened after 56 BCE, which we could only delimit from below because of the absence of any dateable material from the upper layers of the relevant horizons. The derived mean interevent time of these three palaeoevents is 2400 +/- 765 years. We could not correlate any of these palaeoevents with historical earthquakes due to the absence of records in catalogues for the region of interest. Moreover, we used cumulative offsets of the major drainages to calculate the long-term slip rate of 2.7 mm/year since the Pliocene, which exceeds slip rates of other internal faults of Anatolia almost by the factor of two. Our results do not only show significant deformation for the internal parts of Anatolia but also point out a seismic potential of the OF.

AtıfWoS5·OpenAlex5

İncele

Sançar, Taylan; Zabci, Cengiz; Karabacak, Volkan; Yazici, Muge; Akyüz, H. Serdar

The sinistral Malatya-Ovack Fault Zone (MOFZ) is one of the outstanding intraplate deformation belts within Anatolia. The 165-km-long, NE-SW-striking Malatya Fault (MF), which constitutes the southern section of the MOFZ, is separated into five segments according to its surface geometry. These segments have evident morphotectonic features that reflect long- and short-term fault activity, such as morphologic structures offset by as little as 7m and as much as 7.3km. This study provides results from the first paleoseismological investigations on the MF. We find that the last earthquake occurred between 965 and 549 BCE and calculate a recurrence interval of 2275 +/- 605years from evidence for four paleo-events over the last 10ka. Considering fault segmentation and our paleoseismological data, we propose that the accumulated strain on the MF may cause a destructive earthquake (M=7.4) in the near future. Our results support the hypotheses that the MF and other NW-striking dextral and NE-striking sinistral strike-slip faults within the eastern part of Anatolia are plate boundary-related, active deformational structures.

AtıfWoS19·OpenAlex29

İncele

Yazici, Muge; Zabci, Cengiz; Sançar, Taylan; Natalin, Boris A.

Although the westward extrusion of the Anatolian Block is mainly compensated along its boundary faults, the North Anatolian and the East Anatolian shear zones, it is internally deformed in a dominant manner by some strike-slip faults as well. To obtain a better understanding about this intraplate deformation of the Anatolian Block, we investigate the tectonic geomorphology of the Ovaak Fault (OF), which is the northeastern member of the Malatya-Ovaak Fault Zone (MOFZ). Further, we apply the most common geomorphic indices, such as the hypsometric curve and integral, longitudinal channel profiles, channel steepness and concavity, mountain front sinuosity, and valley height-width ratio to characterise and quantify the deformation along the OF and the surrounding region where the regional morphology is shaped with the joint effect of palaeo- and neotectonics and other morphological factors such as palaeoglacial processes. The highest hypsometric integral, steepness and concavity values are generally observed along the northeastern strand of the OF (the Munzur Mountains) and the Kemaliye Region. Further, we interpret that high HI and steepness values indicate a regional tectonic uplift because of either a change in fault geometry, which gives rise to the vertical component on the OF, or a regional high convergence zone. Furthermore, this study gives the first calculation of vertical uplift in the northern margin of the Ovacik Basin (OB) as at least 0.5 mm/y for long term deformation history. Thus, our results exhibit that the OF is one of the intraplate strike-slip faults of the Anatolian Block. (C) 2018 Elsevier B.V. All rights reserved.

AtıfWoS20·OpenAlex22

İncele