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

Zabci, Cengiz; Akyüz, H. Serdar; Sançar, Taylan

The North Anatolian Fault showed a remarkable seismic activity especially between 1939 and 1999, when the westward migrating earthquake sequence created surface ruptures more than 1000 km, leaving unbroken only the Marmara segments, to the west, and the Yedisu Segment, to the east along the main strand of the fault. To understand the palaeoseismicity of the Yedisu Seismic Gap, we undertook trench investigations close to the village of Balaban SarA +/- kaya, on the western part of the Yedisu Segment. We found evidence for at least five surface faulting earthquakes, from which only two are correlated with the 18 July 1784 CE and 27 June 1583 CE historical events. Although the surface rupture of the 1784 CE was reported by other trench studies, the evidence of 1583 CE event is presented for the first time. In consideration with other historical earthquakes, affecting the region east of Erzincan, we suggest that this particular section of the North Anatolian Fault may be in a seismically quiescent period, following a cluster of earthquakes in its near history. In order to test this hypothesis, further studies are needed to increase our knowledge on the temporal and spatial seismic behaviour of the Yedisu Segment, which has potential to create an earthquake with M (w) similar to 7.2 in the near future.

AtıfWoS15·OpenAlex23

İncele