CURRENT SEISMOTECTONIC PROPERTIES OF DENIZLI AND ITS NEAR-REGION (WESTERN TURKEY)

Denizli and its surroundings is one of the most seismically active regions in Turkey. The region is located at the eastern end of the two most important graben (Gediz and Buyuk Menderes) in Western Anatolia. Particularly, in recent years, earthquakes occurring in the region in general are the result of a complex tectonic deformation, dominated by the N-S directed extensional tectonic regime in Western Anatolia. However, the penetration of the African Tectonic Plate under the Anatolian Plate, which is particularly effective on the southwest coasts, makes the defined uniform deformation in the region very complex and as a result of this, intense seismic activity occurs. Denizli Graben, Denizli basin, Denizli Graben- horst system or Great Denizli Fault Zone (GDFZ) are aligned in Northwest Southeast direction situated in the region. Great Denizli Fault Zone consists of many active and young segments. GDFZ is an active young basin about 90 km long, with a width of 25-40 km in places and containing many secondary fault segments. In this region, three earthquake series (Mw >= 5.4-5.8) occurred between the years of 2003-2019. In addition, within the scope of the study, detailed information on earthquakes, occurred in Denizli region in the historical and instrumental period, were compiled. In this study, we analyzed the activity of earthquake clusters that occurred in the region, especially in recent years. With the analysis of the data obtained in the research, intense seismic activity was observed where the central and southern parts of GDFZ were active, and especially around Bozkurt, Actpayam, Honaz, Saraykoy, Buldan. The fault plane solutions of earthquakes (47 in total) that occurred in the region during the instrumental period were compiled within the scope of the study. Additionally, fault plane solutions of 42 recent earthquakes in the region have been determined. Fault plane solutions revealed that earthquakes generally occur on normal faults, containing oblique components. The depths of the earthquakes were in the range of 8-10 km. The stress analysis results show that the extension is in NNE-SSW direction which is dominant in the region. This reveals that in the regional sense, Western Anatolia continues its tectonic evolution under the extensional regime.