EVALUATION OF ALLUVIAL DEPOSITS IN GEMLİK BASIN IN TERMS OF EARTHQUAKE CODES A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY ULAŞ AVŞAR IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN GEOLOGICAL ENGINEERING MAY 2006 ABSTRACT EVALUATION OF ALLUVIAL DEPOSITS IN GEMLİK BASIN IN TERMS OF EARTHQUAKE CODES AVŞAR, Ulaş M.S., Department of Geological Engineering Supervisor: Prof. Dr. Vedat DOYURAN May 2006, 238 pages Gemlik County is located in the Marmara Region (NW Turkey), which has been affected by destructive earthquakes sourced from North Anatolian Fault System throughout its history. The bulk of the settlement rests on alluvial deposits of the Gemlik pull-apart basin. So, it is vital to investigate the foundation soils in this basin and the response of them to earthquakes. Many earthquake codes were established by the authorities in different countries of the world to estimate the possible ground shaking and seismic loads which may act on buildings. In this study, Turkish Earthquake Code (TEC-1998) and Eurocode-8 (EN-1998) have been utilized. The analyses showed that EN-1998 results in more conservative estimates relative to TEC-1998, in terms of spectral ordinates. The source of difference between TEC-1998 and EN-1998 has been investigated and three possible reasons have been identified. The variation is probably due to the different seismic characteristics of Turkey and Europe, different soil amplification levels defined by the codes, and different soil classification procedures of the codes. Keywords: Gemlik, Turkish Earthquake Code, Eurocode8, Soil classification, Response spectrum, North Anatolian Fault System. iv ÖZ GEMLİK HAVZASI ALÜVYON ÇÖKELLERİNİN DEPREM YÖNETMELİKLERİNE DAYANARAK DEĞERLENDİRİLMESİ AVŞAR, Ulaş Yüksek Lisans, Jeoloji Mühendisliği Bölümü Tez Danışmanı: Prof. Dr. Vedat DOYURAN Mayıs 2006, 238 sayfa Gemlik İlçesi, tarihi boyunca Kuzey Anadolu Fay Sistemi’nden kaynaklanan yıkıcı depremlerden etkilenmiş olan Marmara Bölgesi’nde yer almaktadır. Yerleşkenin büyük bölümü Gemlik çek-ayır havzası alüvyon çökelleri üzerindedir. Bu nedenle, havza içindeki zeminlerin deprem sırasında yer sarsıntısına nasıl tepki vereceğinin incelenmesi hayati önem taşımaktadır. Dünyanın çeşitli ülkelerindeki merciler tarafından, olası yer sarsıntılarını ve binalara etki eden sismik yükleri tahmin etmek için, birçok deprem yönetmeliği geliştirilmiştir. Bu çalışmada, Türk Deprem Yönetmeliği (TDY-1998) ile Avrupa Deprem Yönetmeliği (EN-1998) kullanılmıştır. Yapılan analizler, spektral ivmeler açısından, EN-1998’ in TDY-1998’ e göre daha ihtiyatlı tahminlerle sonuçlandığını göstermiştir. TDY-1998 ve EN-1998 arasındaki bu fark incelenmiş ve üç olası neden belirlenmiştir. İki yönetmelik arasındaki fark muhtemelen; Türkiye ve Avrupa’nın farklı sismik özelliklere sahip olmasından, iki yönetmelik tarafından belirlenen farklı zemin büyütmesi seviyelerinden, ve farklı zemin sınıflama yöntemlerinden kaynaklanmaktadır. Anahtar Kelimeler: Gemlik, Türk Deprem Yönetmeliği, Eurocode8, Zemin sınıflaması, Tepki spektrumu, Kuzey Anadolu Fay Sistemi. v To My Parents vi ACKNOWLEDGEMENTS It is an honor for me to express my appreciation to my supervisor Prof. Dr. Vedat DOYURAN for his understanding, continuous support, unlimited thrust and guidance during my Masters program and for his patience during the supervision of this thesis. I would like to express my gratitude to Prof. Dr. Ali Koçyiğit, who has broaden my vision about neotectonics during the active fault field investigations within the context of MEER Project:A3 Component. I am grateful to Prof. Dr. Yener ÖZKAN and Sinan GENCOĞLU, who have encouraged me to study on this subject and shared their enormous experience with me. I gratefully acknowledge Şerafettin DOĞAN, chairman of ÜÇER Consultant Engineering Inc., for his understanding, tolerance, guidance and helpful suggestions. I would especially like to acknowledge Özgür AVŞAR and Nesrin TÜFEKÇİ for their motivation, encouragement, and contributions for the improvement of the document. I would like also to thank my dear friends Ali İMER, Kaan SAYIT and M. Sinan ÖZTÜRK for their help and significant suggestions to understand the geology of the study area. Finally, I would like to thank my family who truly merit the dedication of this thesis. vii TABLE OF CONTENTS ABSTRACT........................................................................................................ iv ÖZ ........................................................................................................................ v DEDICATION.................................................................................................... vi ACKNOWLEDGEMENTS............................................................................... vii TABLE OF CONTENTS.................................................................................. viii LIST OF TABLES............................................................................................... x LIST OF FIGURES ............................................................................................ xi CHAPTER 1. INTRODUCTION ........................................................................................... 1 1.1 Purpose and Scope .................................................................................... 3 1.2 Geographical Setting ................................................................................ 4 1.3 Background Information on Earthquake Codes used in This Study ........ 6 1.3.1 Eurocode 8 (EN-1998) ...................................................................... 7 1.3.1.1 General Information for EN-1998 ........................................... 7 1.3.1.2 Classification According to EN-1998 ...................................... 9 1.3.2 Turkish Earthquake Code (TEC-1998) ........................................... 16 1.3.2.1 General Information for TEC-1998 ....................................... 16 1.3.2.2 Classification According to TEC-1998 .................................. 18 2. GEOLOGY .................................................................................................... 25 2.1 Local Geology......................................................................................... 25 2.1.1 Basement Rocks............................................................................... 26 2.1.2 Quaternary Deposits......................................................................... 31 2.2 Neotectonics and Seismicity ................................................................... 32 2.2.1 Gemlik Fault .................................................................................... 41 2.2.2 Gürle, Gençali and Kurşunlu Faults................................................. 41 2.2.3 Narlıca, Şükrüye and Fevziye Faults ............................................... 44 2.2.4 Çamdibi Fault................................................................................... 44 viii 3. DATA REQUIREMENTS............................................................................. 49 3.1 Seismological Data.................................................................................. 50 3.2 Geological Data....................................................................................... 52 3.3 Geotechnical Data ................................................................................... 56 3.4 Geophysical Data .................................................................................... 59 4. SOIL CLASSES AND CORRESPONDING RESPONSE SPECTRA......... 71 4.1 Classification............................................................................................ 71 4.2 Response Spectra ..................................................................................... 89 5. DISCUSSIONS.............................................................................................. 90 6. CONCLUSIONS AND RECOMMENDATIONS ...................................... 102 REFERENCES ................................................................................................ 104 APPENDICES A. BOREHOLE LOGS ................................................................................ 113 B. LABORATORY TEST RESULTS......................................................... 183 C. SPT BLOW-COUNT AND (Vs) PROFILES.......................................... 194 D. ELASTIC RESPONSE SPECTRA......................................................... 214 E. SPATIAL DISTRIBUTION OF SPECTRAL ORDINATES ................. 227 F. NORMALIZED ACCELERATION RESPONSE SPECTRA FOR RECENT DESTRUCTIVE EARTHQUAKES....................................... 235 ix LIST OF TABLES Table 1.1 Contents of EN-1998 ........................................................................... 8 Table 1.2 Importance classes for buildings........................................................ 10 Table 1.3 Ground types suggested by EN-1998 ................................................ 13 Table 1.4 Parameters describing the Type-1 elastic response spectra ............... 14 Table 1.5 Parameters describing the Type-2 elastic response spectra ............... 14 Table 1.6 Contents of Turkish Earthquake Code 1998...................................... 17 Table 1.7 Effective ground acceleration coefficient (A0) .................................. 18 Table 1.8 Building importance factors for different buildings .......................... 20 Table 1.9 Spectrum characteristic periods........................................................