Neotectonics and seismicity of eastern simav graben, Kütahya – Turkey

Kaplan, Mustafa
The Simav graben is an about 1-9 km wide, 50 km long and approximately WNW-trending active depression. It is located along the western section of a seismogenic belt with a depth of 10-15 km. It is the 10-30 km wide and approximately 500 km long active fault system, namely the Akşehir-Simav fault system. The Simav graben was developed on the northern Menderes Massif under the control of active faults comprising the Simav section of the Akşehir-Simav fault system. The Simav and Akdere grabens include two different fills separated by an intervening angular unconformity: (a) Early Miocene-Middle Miocene deformed graben fill, and (b) Quaternary modern and undeformed graben fill. Geological structures and stratigraphic relationships reveal that there are four tectonic periods differentiated in the study area: (a) N-S extension along the Simav detachment fault, (b) E-W extension and formation of Demirci, Akdere and Selendi grabens, (c) NW-SE compression period characterized by strike-slip faulting, deformation of older graben fills, separation and displacement of the Akdere and Demirci grabens and “non-deposition” in the region, (d) NNE-SSW extension controlled neotectonic period that is characterized by normal faulting and development of both the modern Simav and Akdere grabens. The Simav County and a number of settlements in the size of town and villages are located on and very close to the graben margin-bounding normal faults. Most of them are active and have a capacity of creating destructive earthquakes. This was proved once more by the occurrence of two recent earthquakes. These are the 17 February 2009 Naşa (Simav) (Mw = 5.3) and the 19 May 2011 Söğüt (Simav) (Mw =5.9) earthquakes. The source of the Söğüt earthquake is the Nadarçamı or Seyirkaya fault comprising the Simav fault zone. These faults are normal faults dipping towards NNE. NNE extension and normal faulting mechanism is consistent with the focal mechanism solutions, epicenter location and focus depth and GPS velocity analysis. Simav and a number of settlements located around the active faults are under the threat of earthquake hazard. For this reason, deterministic seismic hazard maps of the study area were prepared to define the earthquake hazard in the Simav region by using the available geological and seismological data as well as a reasonable attenuation relationship for the region. PGA value for Simav city center soil site condition is 0.398 g.


Earthquake focal mechanism and stress tensor analysis along the central segment of the North Anatolian fault
Karasözen, Ezgi; Özacar, Atilla Arda; Kaymakcı, Nuretdin; Department of Geological Engineering (2010)
The North Anatolian Fault (NAF) is one of the world’s largest active continental strikeslip faults, and forms the northern margin of the Anatolian plate. Although its geologic and geomorphologic features are well defined, crustal deformation and associated seismicity around central segment of the NAF is relatively less-known. In this study, we analyzed locations and focal mechanisms of 172 events with magnitude ≥ 3, which are recorded by 39 broadband seismic stations deployed by the North Anatolian Passive ...
Sucuoğlu, Haluk; Ergunay, Oktay; Gencoglu, Sinan (1997-01-01)
In 1995, a swarm of earthquakes affected the city of Dinar, Turkey, which is located in Southwest Anatolia and has a population of 35 000. The mainshock having a local magnitude of 5.9 occurred on 1 October 1995. It was preceded by foreshocks in the previous four days, the largest one with a magnitude of 4.7. These foreshocks initiated structural damage in many buildings, which was then severely aggravated by the mainshock and a strong aftershock two hours later, with a magnitude of 5.0. Numerous aftershock...
Seismic Intensity Maps for the Eastern Part of the North Anatolian Fault Zone (Turkey) Based on Recorded and Simulated Ground-Motion Data
Askan, Aysegul; Karim Zadeh Naghshineh, Shaghayegh; Bilal, Mustafa (2017-01-01)
Seismic intensity maps are employed globally in the aftermaths of earthquakes for rapid response purposes. These maps involve correlations between intensity and peak ground-motion values. In this study, we focus on eastern sections of the North Anatolian fault zone (NAFZ). The eastern segments of the NAFZ are less investigated and have sparse seismic networks compared with western ones. In particular, we study Erzincan, which is a small city in eastern Turkey, located in the conjunction of three active faul...
Plio-Quaternary extensional tectonics of the Central Anatolian Plateau: a case study from the Tuz Golu Basin, Turkey
ÖZSAYIN, ERMAN; Ciner, T. Attila; Rojay, Fuat Bora; DİRİK, RAMAZAN KADİR; Melnick, Daniel; Fernandez-Blanco, David; Bertotti, Giovanni; Schildgen, Taylor F.; Garcin, Yannick; Strecker, Manfred R.; Sudo, Masafumi (2013-01-01)
The Tuz Golu Basin is the largest sedimentary depression located at the center of the Central Anatolian Plateau, an extensive, low-relief region with elevations of ca. 1 km located between the Pontide and Tauride mountains. Presently, the basin morphology and sedimentation processes are mainly controlled by the extensional Tuz Golu Fault Zone in the east and the transtensional Inonu-Eskisehir Fault System in the west. The purpose of this study is to contribute to the understanding of the Plio-Quaternary def...
Reliability of transportation lifeline systems subjected to earthquake loads
Topkara Özcan, Naz; Yücemen, Mehmet Semih; Department of Civil Engineering (2016)
Lifelines, such as highway, gas, water and power distribution systems, are networks which extend spatially over large geographical regions. The assessment of the reliability of a lifeline under seismic loads requires particular attention, since the proper functioning of these systems during or after a destructive earthquake is very important. The main objective of this study is to investigate the system reliability of lifeline networks subjected to earthquake loads by concentrating on highway systems consis...
Citation Formats
M. Kaplan, “Neotectonics and seismicity of eastern simav graben, Kütahya – Turkey,” M.S. - Master of Science, Middle East Technical University, 2014.