NEOTECTONICS AND SEISMICITY OF EASTERN SİMAV GRABEN, KÜTAHYA – TURKEY A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY MUSTAFA KAPLAN IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN GEOLOGICAL ENGINEERING SEPTEMBER 2014 Approval of the thesis: NEOTECTONICS AND SEISMICITY OF EASTERN SİMAV GRABEN, KÜTAHYA – TURKEY submitted by MUSTAFA KAPLAN in partial fulfillment of the requirements for the degree of Master of Science in Geological Engineering Department, Middle East Technical University by, Prof. Dr. Canan Özgen _____________________ Dean, Graduate School of Natural and Applied Sciences Prof. Dr. Erdin Bozkurt _____________________ Head of Department, Geological Engineering Prof. Dr. Ali Koçyiğit _____________________ Supervisor, Geological Engineering Dept., METU Examining Committee Members: Prof. Dr. Erdin Bozkurt _____________________ Geological Engineering Dept., METU Prof. Dr. Ali Koçyiğit _____________________ Geological Engineering Dept., METU Prof. Dr. F. Bora Rojay _____________________ Geological Engineering Dept., METU Prof. Dr. Reşat Ulusay _____________________ Geological Engineering Dept., HÜ Assist. Prof. Dr. A. Arda Özacar _____________________ Geological Engineering Dept., METU Date: 03.09.2014 I hereby declare that all information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work. Name, Last Name: Mustafa Kaplan Signature: iv ABSTRACT NEOTECTONICS AND SEISMICITY OF EASTERN SİMAV GRABEN, KÜTAHYA – TURKEY Kaplan, Mustafa M.S., Department of Geological Engineering Supervisor: Prof. Dr. Ali Koçyiğit September 2014, 121 pages 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 v “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. Keywords: neotectonic, seismicity, seismic hazard, Simav graben, Simav fault zone, GPS, PGA, DSHA vi ÖZ SİMAV GRABENİ DOĞU KESİMİNİN NEOTEKTONİĞİ VE DEPREMSELLİĞİ KAPLAN, Mustafa Yüksek Lisans, Jeoloji Mühendisliği Bölümü Tez Yöneticisi: Prof. Dr. Ali KOÇYİĞİT Eylül 2014, 121 sayfa Simav grabeni yaklaşık 1-9 km genişlikte, 50 km uzunlukta BKB uzanımlı aktif bir çöküntü alanıdır.Simav grabeni 10-15 km derinlikteki bir sismik kuşağın batı kesiminde yeralır. Bu sismik kuşak 10-30 km genişlikte ve 500 km uzunlukta olan Akşehir-Simav fay sistemidir. Simav grabeni, Akşehir-Simav fay sisteminin Simav kısmını oluşturan aktif fayların kontrolünde kuzey Menderes Masifinde gelişmiştir. Simav ve Akdere grabenleri aradaki açısal uyumsuzlukla birbirinden ayrılan iki farklı dolgu içerir. (a) Erken Miyosen-Orta Miyosen deforme olmuş dolgu, ve (b) deforme olmamış Kuvaterner dolgu. Jeolojik yapılar ve stratigrafik ilişkiler bölgede ayırılabilen 4 farklı tektonik dönem olduğunu göstermiştir. (a) Simav sıyrılma fayı üzerinde K-G genişleme, (b) D-B genişleme ve Demirci, Akdere ve Selendi grabenlerinin oluşması, (c) Doğrultu atımlı faylanma, eski graben dolgusunun deforme olması, Akdere ve Demirci grabenlerinin ayrılması ve ötelenmesi, ve bölgede çökelimin duraksamasıyla temsil edilen KB-GD sıkışma dönemi, ve (d) vii normal faylanma ve güncel Akdere ve Simav grabenlerin oluşumu ile karakterize edilen, KKD-GGB genişleme kontrolündeki neotektonik dönem. Simav ilçesi ve köy-kasaba büyüklüğündeki birçok yerleşim birimi Simav grabenini sınırlayan normal fayların üzerinde ya da çok yakınında bulunmaktadır. Bu fayların çoğu aktiftir ve yıkıcı deprem üretme potansiyeline sahiptir. Bu durum yakın zamanda meydana gelen iki depremle birkez daha kanıtlanmıştır. Bu depremler 17 Şubat 2009 Naşa (Simav) (Mw=5.3) ve 19 Mayıs 2011 Söğüt (Simav) (Mw=5.9) depremleridir. Söğüt depreminin kaynağı Simav fay kuşağını oluşturan Nadarçamı ya da Seyirkaya faylarıdır. Bu faylar KKD eğimli normal faylardır. KKD genişleme ve normal faylanma mekanizması, odak mekanizması çözümleri, episantır konumu, odak derinliği ve GPS hızları analiziyle uyumludur. Aktif fayların çevresinde bulunan Simav ve birçok yerleşke deprem tehlikesi tehdidi altındadır. Bu nedenle,Simav bölgesindeki deprem tehlikesini ortaya koymak için, mevcut jeolojik ve sismolojik verilerle birlikte bölge için uygun azalım ilişkileri kullanılarak deterministik ve olasılıksal deprem tehlike haritaları hazırlanmıştır. Simav şehir merkezi toprak zemin sınıfı için PGA değeri 0.398 g olarak bulunmuştur. Anahtar kelimeler: neotektonik, depremsellik, deprem tehlikesi, Simav grabeni, Simav fay zonu, GPS viii To my family, ix ACKNOWLEDGEMENTS First of all, I would like to thank my supervisor Prof. Dr. Ali Koçyiğit for his clear guidance, endless support, encouragement, sharing his knowledge and critically editing of the manuscript. Studying under his supervision was a priceless experience for me to learn about structural geology and tectonics. He is more than a supervisor for me and words will never be enough to express my sincere gratefulness to him. I am grateful to Prof. Dr. Erdin Bozkurt for fruitful discussions about the thesis and giving valuable insight into the discussions on the views about extension in the region. His attitude always inspired and encouraged me during the writing of this thesis. I want to express my gratitude to Prof. Dr. Reşat Ulusay for the time he spent reading the thesis without missing any typing mistake and inconsistency. I am thankful to Prof. Dr. F. Bora Rojay who critically reviewed the thesis and shared his knowledge about not only for the geology of the region but also for the geology of Turkey. I would also thank to Assist. Prof. A. Arda Özacar for critically reviewing the thesis and providing smart solutions whenever I was in despair. I would like to M. Abdullah Kelam, Haydar Merdin, İlkay Mudun, Aydın Çiçek, Hakan Tanyaş and Erhan Gülyüz for their valuable helps during different stages of this work. Your helps and efforts made great effect on this study. I also want to thank to my friends at the department, Okay Çimen, Mustafa Y. Kaya, Yavuz Kaya, Felat Dursun, Faruk Berber, Arzu Arslan, Özge Ünlüce, Bülent Tokay as well as other friends and staff for their friendship and support. I am so glad I have my friends out of the department Erçin Savur, Niyazi Gürsoy, Bahtiyar Yılmaz, Ebru Topsakal, Can Barış Agbay and others who always gave support without questioning. At last but not the least, I want to thank to my family for patience and encouragement before and during my studies. Especially, I am grateful to my beloved, Hülya, for her continuous support, love and confidence to me. x TABLE OF CONTENTS ABSTRACT .............................................................................................................. v ÖZ ............................................................................................................................. vii ACKNOWLEDGEMENTS ........................................................................................ x TABLE OF CONTENTS ......................................................................................... xi LIST OF TABLES ..................................................................................................