Geological and Seismological Observations after 8 August 2019 Bozkurt (Turkey) Earthquake

Abstract

Book DOI: 10.21467/abstracts.93 Tectonic settings. The study area is located on the inner SW Anatolia where is dominated by graben systems. It is on the Acigöl Graben and many other can be traced nearby like Civril-Baklan, Burdur Grabens (Figure 1). They are all in NW-SW direction and bounded by active fault line. These faults caused some remarkable earthquakes like Burdur (M=5.9) at 1971 and Dinar (M=6.1) at 1995.Acıgöl Graben is mainly in NW-SW direction but it turns to E-W at the west end. Maymundagi fault is also parallel to the graben and forms the northern boundary along 14 km than it continues towards Alikurt village in E-W direction along 17 km. Gemis fault bounds the graben in the south and its length is about 25 km. It reaches up to Gemis village and after it splits up several segments (1.5 km to 9 km) mainly in E-W direction. Seismological features. The region is very active in terms of seismicity. Bozkurt town is located on the Gemis Fault. Seismic activity of the area has been known for long time both from instrumental and historical records (AFAD, 2019). When the earthquake focal mechanism solutions are analyzed, BU stated that the fault forming the earthquake is a normal fault in the E-W direction, and AFAD suggests an approximately WNW-ESE direction with 440 dip angle to south that is Maymundagifault. However, the epicenter point of the fault is on the north of the Maymundagi fault. It means Maymundagi fault has not caused the earthquake. Slope directions and focal mechanism solutions of the both faults Gemis fault has produced the earthquake. Since the Gemis fault that forms the earthquake is inclined north, the epicenter point of the earthquake appears in the north, therefore in the Bozkurt region. In other words, the focal centers of the main earthquake and aftershocks are located in the northern region of the graben. The epicenter points are concentered on the northern part of graben around Bozkurt town as Gemis fault inclination is towards north. Conclusions. Bozkurt, Denizli located in the western part of Turkey, has been hit by an earthquake with a magnitude of 6.0 (M) on August 8, 2019. The earthquake has caused hundreds of aftershocks during six months. The ground motion has produced observable damage in a rather large area. Although the earthquake is moderate, its effects on the structures were serious. This paper presents the geological and seismological observations on the affected area. The epicentre of the main shock is on the Maymundagi that is a part of Gemis Fault segment in WNW-ESE direction. Although the epicentre is far away from many crowded towns on the plain, it has caused some seismic damages on the reinforced concrete (RC) and masonry structures. Some villages like Dutluca Armutalan and Mecidiye are close to epicentre and they showed less damage because of the stiff rock foundation compared to the ones on the alluvium.