Akademik Veri Yönetim Sistemi
ASASE2021, Ankara, Türkiye, 20 - 21 Mayıs 2021, cilt.30, ss.35
The 45-km-long, E-W to NW–SE-striking Manisa Fault (MF), which constitutes the western section of the Gediz graben system, is made up of
two main fault segments. Previous studies are mostly concentrated on the western segment of MF to decipher Quaternary-Holocene
characteristics. According to previous studies, the western segment is responsible for three paleo-earthquakes which correspond to 926 AD,
1595 or 1664 AD, with the most recent event in 1845 AD. To shed light on (i) Holocene palaeoseismic activity of MF, (ii) the earthquake
recurrence interval and elapse time since the last activity of fault, five trenches were excavated on the eastern segments. Evaluation of field
observations suggests that the MF has been the source of multiple Late Pleistocene and Holocene surface-rupturing earthquakes.
Detailed studies of trench walls and dating studies signify that the eastern segment of MF is responsible for at least five surface faulting
earthquakes during the Holocene. According to Oxcal distribution using the Bayesian methods, the events are: E1: 30,7±8,8ka; E2: 15,0±5,0ka;
E3: 6,3±1,6ka; E4: 2,6±0,9ka; E5: 0,6±0,4ka and E6: 0,1±0,1 ka. When the events are compared with the historical earthquakes, the E3, E4, and
E5 events may correlate with the earthquakes of 17 AD, 926 AD, 1845 AD, respectively. According to these findings, it is understood that both
fault segments were broken during the 926 AD and 1845 AD earthquakes, and that ruptured in a way that triggers each other.
On the other hand, in the light of the proposed interevent time, the estimation of the recurrence interval for the MF is varied between 0.16 and
3.5 ka for the Holocene. The elapsed time since the most recent surface ruptured earthquake on the MF is 160 years. Accordingly, MF poses a
significant hazard, and therefore, it is necessary to assess the potential seismic hazard for the densely populated area of Manisa, Western
Anatolia.