Geological features of the Gediz (Kütahya) and surroundings

Aim of this study, to carry out geological features of study area about 216 km2 where located at Eski Gediz (Kütahya) and the surroundings in the Central-Western Anatolia and limited by Akkaya at north, Kayacık at east, Sazak at west and Gediz at south.Paleozoic Baybuyan and Arıkaya Formations constitute the basement of the study area. Early Miocene Kürtköyü Formation composed of conglomerates, Middle Miocene Yeniköy Formation composed of limestones, Middle Miocene Hisarcık Formation composed of conglomerates, sandstones and fossiliferous limestone and Demirbilek Member of Late Miocene Tunçbilek Formation composed of marls uncomformably overlies the basement units, respectively. This sedimentary sequence is cut by Early Miocene Dereköy Volcanics (In this studying; K-Ar aging; 18,0±0,5 My), Middle Miocene Karacahisar Volcanics and Late Miocene Oklukdağı Volcanics. Late Pliocene Emet Formation composed of cherty limestones uncomformably overlies the older units. Additionally, the youngest sedimentary units in the study area are Quaternary alluvium.According to kinematic analysis data taken from fault planes, before the Late Pliocene; strike slip faulting under NE-SW directed compressional regime and normal faulting under NE-SW directed extensional regime were active in the study area. In the Late Pliocene strike slip faulting under NW-SE directed compressional regime was active. In the Quaternary normal faulting under NNE-SSW directed extensional regime was active. In this study, 28 March 1970 Gediz Earthquake (M=7.6) surface ruptures are investigated. Gediz earthquake occurred on two faults which follow each other. One of this fault named Hamamlar Fault has E-W trend, the other one is N-S trend Muhipler Fault. The surface ruptures obtained from the studied area are generally parallel to the N-S directed Muhipler Fault. According to focal mechanism inversion results taken from earthquakes occured Gediz and vicinity between 1970-1972 and after Gediz earthquake, normal faulting under NNE-SSW directed extensional regime is determined. This regime is compatible with present activity.Key words: Central-Western Anatolia, K-Ar Aging, Kinematics Analysis, Gediz Earthquake, Muhipler Fault.