Palaeoseismology of the Havran-Balıkesir Fault Zone: evidence for past earthquakes in the strike-slip-dominated contractional deformation along the southern branches of the North Anatolian fault in northwest Turkey

Abstract

The Havran-Balıkesir Fault Zone (HBFZ) is one of the major active structures of the Southern Marmara Region, which has been shaped by the southern branch of North Anatolian fault since the Pliocene. HBFZ is a 10-12 km wide, 120 km long, right-lateral strike-slip fault zone that consists of two ENE-striking main faults, namely, the Havran-Balya and Balıkesir faults. The 90-km-long Havran-Balya fault exhibits right-stepping en echelon geometry and is made up of (1) Havran, (2) Osmanlar, (3) Turplu and (4) Ovacık fault segments. On the eastern part, the 70-km-long Balıkesir fault is divided into two fault segments; (1) Gökçeyazı and (2) Kepsut. We estimated the long-term slip rate between 3.59 and 3.78 mm/yr using river offset. The Kepsut, Gökçeyazı and Ovacık fault segments are capable of generating an earthquake with a moment magnitude of up to 7.2. Detailed palaeoseismological studies show that the HBFZ is responsible for some surface faulting earthquakes with an average recurrence interval of 1000-2000 years during the late Holocene. Considering the fact that there was no evidence of a surface-ruptured earthquake for 2000 years, it can be stated that there is a seismic gap on the Gökçeyazı fault segment.

Holocene seismic activity of the Priene–Sazlı Fault revealed by cosmogenic 36Cl,Western Anatolia, Turkey

“…1 Sazlı Fault are compatible with previous studies in Western Anatolia. For example, the Havran-Balıkesir and Edremit fault zones in the northern part of Western Anatolia with recurrence interval of earthquakes in the range of 1000-2000 years were documented by Sözbilir et al (2016aSözbilir et al ( , 2016b. In addition, our results fit the upper limit of the recurrence interval for major earthquakes in the Büyük Menderes Fault Zone of 250-1900 years (Altunel et al, 2009).…”

Paleosi̇smoloji̇k Bulgular Işiğinda Orhaneli̇ Fayinin Holosen Akti̇vi̇tesi̇, Bursa, Kb Anadolu

“…In this palaeoseismological study, structural geology, sedimentology, geomorphology and radiocarbon/OSL dating methods were applied. It is expected that this study and other previous studies will help to understand the seismicity of the region (Kop et al, 2016;Kürçer et al, 2017;Özalp et al, 2013Sözbilir et al, 2016a, b) and the seismic hazard assessment.…”

Kinematics of the Havran-Balıkesir Fault Zone and its implication on geodynamic evolution of the Southern Marmara Region, NW Anatolia

“…The main late Cenozoic structures mapped around the Balıkesir area is named here as also Havran-Balıkesir Fault Zone, which is a 10-12 km wide, 120 km long, approximately N70°E-trending fault zone comprising several riedel faults that display a well-developed shear zone pattern with en-échelon elongated hills. Emre et al (2011) and Sözbilir et al (2016a) suggest that the fault zone consists of two E-W-striking faults, namely Havran-Balya Fault (HBF) to the west, Balıkesir Faults (BF) to the east (Figure 2(a)).…”

“…Because of its critical geological position, definition of this structure was a new development for the region in context of the structural transition of two different geological provinces. After this documentation, Sözbilir et al (2016a) performed trench-based palaeoseismological investigations in order to dating of past faulting events together with estimates of long-term sliprates and recurrence intervals. Although, there is still not enough detailed information about the kinematics and tectonic evolution of the HBFZ, which have a great potential to provide significant data for understanding the geodynamics of the SMR.…”