Browsing by Author "Sözbilir, Hasan"

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Çanakkale-Ayvacık deprem fırtınasının (14 Ocak-20 Mart 2017) sismik kaynakları
(Eskişehir Teknik Üniversitesi, 2018) Sözbilir, Hasan; Baba, Alper; Uzel, Bora; Sümer, Ökmen; Eski, Sümer; Softa, Mustafa; Tepe, Çiğdem; Özkaymak, Çağlar; Baba, Alper; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Bu çalışmada, 14 Ocak 2017 ile 20 Mart 2017 tarihleri arasında Çanakkale-Ayvacık çevresinde meydana gelen depremlerin (Mw=5.3 ve daha küçük 1000’e yakın deprem) sismik kaynakları Şubat-Mart 2017 tarihleri arasında yapılan saha çalışmalarıyla 1/25.000 ölçeğinde haritalanmış ve ilgili faylarda kinematik analiz çalışmaları yapılmıştır. Haritalama çalışmalarımıza göre, oluşan depremlerin sismik kaynağı olan Tuzla Fayı’nın toplam uzunluğu (deniz altındaki uzantısıyla birlikte) 25 km’ye erişir ve Çamköy ile Paşaköy segmenti olarak adlandırılan iki segmentten yapılıdır. 15 km uzunluğundaki Çamköy segmenti, Tuzla Köyü’nün kuzeybatısındaki sahilden itibaren güneydoğuya doğru Tamış köyü güneybatısına kadar haritalanmıştır. 10 km uzunluğundaki Paşaköy segmenti ise, Kolfay Köyü’nden başlar ve güneydoğuya doğru Behram Köyü doğusunda Edremit Fayı ile birleşir. Şimdiye kadar oluşan depremlerin önemli bir bölümü KB-GD uzanımlı Tuzla Fayı’nın deformasyon zonu boyunca ve fayın düşen bloğu üzerindeki Tuzla Köyü ile Assos arasındaki bölgede meydana gelmiştir ve Tuzla Fayına ait Çamköy segmentinin kırıldığını göstermektedir. Henüz kırılmayan Paşaköy segmenti ise Mw=6.18büyüklüğündeki bir deprem üretme potansiyeline sahiptir. Tarafımızdan yapılan haritalama çalışmalarına göre, iki segmente ait fay kolları Tamış Köyü güneyinde birbirine oldukça yaklaşmış bulunmaktadır. Tuzla Fayına ait iki segmentin birleşerek tek bir deprem üretmesi halinde, Mw=6.7 büyüklüğündeki bir depreme karşılık gelen enerjinin açığa çıkabileceği öngörülebilir. Depremlerin zaman ve mekân içerisindeki dağılımları ve büyüklükleri, tek bir ana şoka bağlı olarak gelişmediklerini, birbirine paralel-yarı paralel fay kollarının birbirini tetiklemesi sonucunda oluşan bir deprem fırtınası özelliği taşıdıklarına işaret etmektedir. Bu durum, Çamköy segmentinin birbirine bağlı sintetik ve antitetik nitelikli çok sayıda fay parçası içermesinden kaynaklanmaktadır. Bu fay kollarına ait kinematik veriler, Tuzla Havzası’nın KD-GB doğrultusunda gelişen çekme kuvvetleri etkisinde şekillendiğini göstermektedir.
Citation - WoS: 25
Citation - Scopus: 25
Conceptual Model of the Gülbahçe Geothermal System, Western Anatolia, Turkey: Based on Structural and Hydrogeochemical Data
(Elsevier Ltd., 2017-07) Uzelli, Taygun; Uzelli, Taygun; Baba, Alper; Baba, Alper; Mungan, Gamze Gül; Dirik, Ramazan Kadir; Sözbilir, Hasan; 03.03. Department of Civil Engineering; 01.01. Units Affiliated to the Rectorate; 01. Izmir Institute of Technology; 03. Faculty of Engineering
The Gülbahçe Geothermal Field is located on the eastern margin of the Karaburun Peninsula, about 45 km from the city of İzmir, western Anatolia, Turkey. The stratigraphy of the study area is represented by a Miocene volcano-sedimentary succession, including several sedimentary and volcanic units. These units overlie the basement rocks of the Karaburun Platform and Bornova Flysch Zone which consist of sandstones, shales and carbonate blocks. These rock units are cut and deformed by a series of NW-SE- to NE-SW-trending faults, extending from Sığacık Bay to Gülbahçe Bay. Structural studies suggest that while most of the geothermal systems in western Anatolia are controlled by normal faults, the geothermal system at Gülbahçe is controlled by a strike-slip dominated shear zone, previously named the İzmir-Balıkesir Transfer Zone. Along the fault zone, associations of active fault segments accommodate deep circulation of hydrothermally modified sea water, and thus the resulting negative flower structure is the primary control mechanism for the geothermal system. Hydrogeochemical properties of the field show that surface temperature of fluid ranges from 30 to 34 °C. Geothermal fluids in Gülbahçe have high salinity (EC > 34 mS/cm) and low enthalpy. Piper and Schoeller diagrams indicate that geothermal fluid is in the NaCl facies. Chemical geothermometers suggest that the reservoir temperature is around 53–136 °C. The isotopic data (oxygen-18, deuterium and tritium) suggest that geothermal fluids are formed by local recharge and deep circulation of sea water.
Citation - WoS: 31
Citation - Scopus: 35
Distribution of Geothermal Arsenic in Relation To Geothermal Play Types: a Global Review and Case Study From the Anatolian Plate (turkey)
(Elsevier, 2021) Baba, Alper; Uzelli, Taygun; Uzelli, Taygun; Baba, Alper; Sözbilir, Hasan; 03.03. Department of Civil Engineering; 01.01. Units Affiliated to the Rectorate; 01. Izmir Institute of Technology; 03. Faculty of Engineering
Arsenic has a natural cycle as it travels underground. It can mix with geothermal fluid in different ways under the control of magmatic and tectonic processes. Geogenic arsenic is present in many geothermal fields in the world at concentrations above the limits set for human health. The arsenic content of geothermal fluids is also related to the concept of geothermal play type, which forms geothermal systems, because the natural processes that form the geothermal system also control the arsenic cycle. In this study, an attempt is made to explain the relationship between the geothermal play type concept and geothermal arsenic circulation. For this purpose, geothermal field examples are given from around the world and Turkey. The result shows that arsenic concentrations can reach significant levels along with plate tectonic boundaries in the world. When arsenic concentrations were evaluated, the effect of major faults on the Anatolian Plate was clearly seen. Also, in the Anatolian plate where volcanosedimentary units are common, geothermal fluids caused more effective alteration along with structural control and increased arsenic concentrations in geothermal systems. This interaction between structural elements, geothermal fluid, and the arsenic cycle shows that the concept of play type in geothermal systems should also be taken into consideration. It was determined that the places with high arsenic values are located within the convective-non-magmatic extensional geothermal play types such as Western Anatolian Extensional System and the North Anatolian Fault. The concept of play type in geothermal systems includes all systematic and external factors that make up these processes. For this reason, it is very important to evaluate the play type classification together with the arsenic cycle.
Citation - WoS: 4
Citation - Scopus: 13
Effects of Seismic Activity on Groundwater Level and Geothermal Systems in İzmir, Western Anatolia, Turkey: the Case Study From October 30, 2020 Samos Earthquake
(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2021) Uzelli, Taygun; Baba, Alper; Bilgiç, Esra; Bilgiç, Esra; Öztürk, Bahadır; Uzelli, Taygun; Baba, Alper; Öztürk, Bahadır; Sözbilir, Hasan; Tatar, Orhan; 01. Izmir Institute of Technology; 03.03. Department of Civil Engineering; 01.01. Units Affiliated to the Rectorate; 03. Faculty of Engineering
The October 30, 2020 Samos earthquake (Mw 6.6) affected the Aegean Sea and environs, caused destruction and loss of life in the city of İzmir located 70 km away from the earthquake epicenter. Before this earthquake, water resources were monitored in the areas of Bayraklı, Gülbahçe, and Seferihisar. For this purpose, 10 groundwater monitoring wells were drilled in the Bayraklı area, where groundwater level, temperature, and electrical conductivity changes were monitored at 1-h intervals in 5 wells. Besides physical parameters such as groundwater levels, temperatures and electrical conductivities, hydrogeochemical cations, and anions measured in the study area. Change in the groundwater levels was observed before, during, and after the Samos earthquake. A trend of rising groundwater level was observed two days before the mainshock, to a height of 10 cm, and the level was maintained till the end of the earthquake. The water levels returned to its original height after about 7 to 10 days of the earthquake. Moreover, electrical conductivity (EC) values were changed because of the interaction with the surrounding rocks and well walls, mixing with different waters during the earthquake shaking. The essential anomalies were observed in the geothermal fields of Gülbahçe and Seferihisar. Due to this earthquake, new geothermal springs emerged along the NE-SW trending Gülbahçe and Tuzla faults, located about 50 to 20 km from the Samos earthquake epicenter, respectively. The new geothermal waters are in Na-Cl composition and similar to other geothermal springs in the region. While the recorded water temperatures in the new geothermal springs vary from 40 to 45 °C in Seferihisar, it was measured between 35 and 40 °C in Gülbahçe. Due to these anomalies, it is found essential to monitor the effect of the earthquake on the physical and chemical characteristics of the groundwater and its usefulness in earthquake predictions.
Evidence for Sea Water Intrusion in Karstic Aquifer of Karaburun Peninsula, Nw Turkey
(International Water Association, 2017) Baba, Alper; Gündüz, Orhan; Gündüz, Orhan; Baba, Alper; Şimşek, Celalettin; Elçi, Alper; Murathan, Alim; Sözbilir, Hasan; 03.07. Department of Environmental Engineering; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Karstic aquifers are considered to be significant sources of groundwater and are mostly under threat due to sea water intrusion in many parts of the world. Seawater intrusion is also a common problem on karstic aquifers of Karaburun Peninsula in north of Mediterranean Region. The hydrogeology of Karaburun Peninsula is fairly complex and is mostly characterized by highly permeable karstic formations with significant water storage in an otherwise water scarce area. The karstic aquifers of the region were recently found to be under severe salt water intrusion, which significantly altered the position of fresh water/sea water interface as a result of excessive pumping and fault zones controlling the karstic network.
Citation - Scopus: 3
High Arsenic Levels in Groundwater Resources of Gediz Graben, Western Turkey
(CRC Press, 2016) Baba, Alper; Baba, Alper; Gündüz, Orhan; Gündüz, Orhan; Şimşek, Celalettin; Elçi, Alper; Sözbilir, Hasan; Murathan, Alim; 03.07. Department of Environmental Engineering; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Gediz Graben situated in western Turkey is an area containing extensional structures with active tectonics and geothermal systems that serves as a suitable environment for the presence of high levels of arsenic (As) in groundwater. The results of a comprehensive monitoring program in the basin revealed that the maximum As concentration detected during the monitoring program was 3086 ppb and the average value was calculated to be 23.63 ppb. In addition, As levels in 28% of the water samples were above the 10 ppb limit value making them unsuitable for drinking water supply. These high As concentrations in the basin was mostly associated with long detention times of water in altered rocks located along detachment faults, strong water–rock interaction processes in the alteration zones and anthropogenic influences made within the geothermal fluid reservoir. © 2016 Taylor & Francis Group, London.
Citation - WoS: 9
Citation - Scopus: 9
Hydrogeology and Hydrogeochemistry of the Geothermal Systems and Its Direct Use Application: Balçova-Narlıdere Geothermal System, İzmir, Turkey
(Elsevier, 2022-09) Baba, Alper; Tonkul, Serhat; Sözbilir, Hasan; Demir, Mustafa Muammer; Sayık, Tolga; Uzelli, Taygun; Arslan, Sinan; Baba, Alper; Uzelli, Taygun; Tonkul, Serhat; Demir, Mustafa Muammer; 03.06. Department of Energy Systems Engineering; 03.03. Department of Civil Engineering; 01.01. Units Affiliated to the Rectorate; 03.09. Department of Materials Science and Engineering; 01. Izmir Institute of Technology; 03. Faculty of Engineering
The Balçova-Narlıdere geothermal system, located in western Turkey, is an extensional domain type geothermal play. Geological, hydrogeological, and geothermal studies have been done in the Balçova-Narlıdere geothermal field since 1960. As a result of these studies, production and research wells were drilled in the area by both the public and private sectors. Of the 37 wells drilled in the Balçova-Narlıdere geothermal field, 26 were drilled by İzmir Geothermal Energy Company Inc. (16 productions, 4 re-injection, 4 gradientst, 2 unused) and 11 by the İzmir Governorship Investment Monitoring and Coordination Department and companies in the private sectors. There are two reservoirs, one shallow and one deep, in the geothermal field. Well depths are less than 200 m in the shallow reservoir. The deep production wells have depths ranging from 400 to 1,100 m and reservoir temperatures reaching 140 °C. The electrical conductivity (EC) values in the shallow production wells range from 1,200 to 1,500 µS/cm. EC values in the deep production wells vary from 1,871 to 2,025 µS/cm, and all geothermal fluids in the field are mineral-rich waters. In the İzmir geothermal district heating system, the newest technologies are used, and operational costs are very low. İzmir Geothermal Energy Company Inc. has been operating since 1996 and has reached 38,460 residences. The current capacity of the system is approximately 160 MWt. Cooling systems continue to spread in Turkey, focusing on electric air conditioning systems and geothermal heating systems, but both economic and applicability problems have slowed the expansion of cooling systems. However, İzmir Geothermal Energy Company Inc. began operating its first geothermal cooling application in Balçova in 2018, cooling 1,900 m2 of the indoor area by lithium bromide absorption and 90/85 °C geothermal temperature regime by supplying 6/9 °C clean cold water to the coolers in the buildings. These results show that the extensional domain type geothermal system in the Balçova-Narlıdere region is suitable for both heating and cooling applications
Investigation of Sea Water Intrusion in Coastal Aquifers: a Case Study From Karaburun Peninsula, Turkey
(The International Association for Hydro-Environment Engineering and Research (IAHR), 2015) Baba, Alper; Baba, Alper; Şimşek, Celalettin; Gündüz, Orhan; Gündüz, Orhan; Elçi, Alper; Murathan, Alim; Sözbilir, Hasan; 03.07. Department of Environmental Engineering; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Groundwater is an important natural resource; as of today, more than 2 billion people depend on groundwater. Determination of the quantity of available water resources is crucial due to continuously increasing water demand and unequal spatial distribution of water in the world. Coastal areas are typically considered to be areas of limited supply and large demand and groundwater is mostly the resource that is used for water supply purposes for coastal communities. Thus, there exist numerous studies in literature that focus on the determination of the groundwater characteristics in coastal regions with particular emphasis on the geological, hydrogeological and hydrochemical properties of coastal groundwater. Coastal aquifers are considered to be significant water resources and are mostly under threat due to salt water intrusion. The reason for salt water intrusion is mostly anthropogenic such as over exploitation but occasionally natural causes like tectonic boundaries or fault lines could be influential. When coupled with low recharge rates that are common in semi-arid regions such as the Mediterranean, effective and sustainable supply of water with sufficient quality and quantity becomes a real challenge for coastal communities.
Investigation of sea water intrusion in the Ildırı Region (Çeşme-Turkey) coastal aquifer
(Nevşehir Hacı Bektaş Veli Üniversitesi, 2017) Baba, Alper; Gündüz, Orhan; Gündüz, Orhan; Baba, Alper; Şimşek, Celalettin; Elçi, Alper; Murathan, Alim; Sözbilir, Hasan; 03.07. Department of Environmental Engineering; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Coastal aquifers are considered to be significant sources of groundwater and are mostly under threat due to sea water intrusion as a result of anthropogenic (i.e., over exploitation, reduced recharge due to climate change, etc.) and natural sources (i.e., tectonic features and fault line orientations) in many parts of the world. Seawater intrusion is also a common problem on coastal aquifers of Turkey.
Karaburun Yarımadası Güneybatısındaki Su Kaynaklarının Hidrojeokimyasal Özellikleri
(TMMOB Jeoloji Mühendisleri Odası, 2015) Baba, Alper; Gündüz, Orhan; Şimşek, Celalettin; Baba, Alper; Gündüz, Orhan; Elçi, Alper; Murathan, Alim; Sözbilir, Hasan; 03.07. Department of Environmental Engineering; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
İzmir’in batı ucunda yer alan Karaburun Yarımadası turizm açısından Türkiye’nin en önemli yerlerinden bir tanesidir. Yerli ve yabancı turistlerin Çeşme ve Alaçatı’da yer alan turizm tesislerinde konaklamalarının yanı sıra, bu kesimlerde yer alan ikinci konutlar nedeni ile de yaz ayları nüfusunu çok arttırdığı görülmektedir. 2012 yılı verilerine göre Çeşme ilçe nüfusu 34563 kişi olarak görülmekle birlikte, özellikle 2014 Temmuz ve Ağustos aylarında nüfusun altı yüz bin kişiye ulaştığı vurgulanmaktadır. Bu nedenle, İlçenin en önemli sorunu su olmuştur. Çeşme ilçesinin su ihtiyacı, Alaçatı Barajı ve Karaburun Yarımadası’nın güney batısında yer alan Ildır Bölgesi’ndeki kuyulardan sağlanmaktadır. İklim değişiminin bir sonucu olarak son yıllarda, barajdaki su seviyesi çok azalmıştır. Buna ek olarak, alandaki yeraltısuyu kaynakları da aşırı çekimin bir sonucu olarak tuzlanmaya başlamıştır. Çeşme’nin başlıca su kaynağını oluşturan, Ildır karstik kaynaklar ile ilgili DSİ, İller Bankası ve Turizm Bakanlığı tarafından bir dizi araştırma yapılmıştır. Yapılan çalışmalarda, Ildır karstik kireçtaşları yeraltısuyu kaynak kapasitesi, karstik akiferin deniz ile olan ilişkisinin sınırlandırılması ve geçirimsiz bir perdenin oluşturulması üzerine durulmuştur. DSİ tarafından Ildır sahil kesiminde açılan sondaj kuyularında, kıyı boyunca deniz suyu girişiminin olduğu, alanda aktif karst derinliğinin ortalama 60 m olduğu belirtilmiştir.
Karaburun Yarımadası’ndaki Yeraltı Suların Fiziksel ve İzotopik Özellikleri
(DSİ, 2016) Baba, Alper; Gündüz, Orhan; Şimşek, Celalettin; Baba, Alper; Solak, Onur; Gündüz, Orhan; Elçi, Alper; Murathan, Alim; Sözbilir, Hasan; 03.07. Department of Environmental Engineering; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Türkiye'nin batısında yer alan Karaburun Yarımadası'nın içme suyunun tamamına yakını yeraltı sularından karşılanmaktadır. Özellikle yaz dönemlerinde bölgedeki nüfus artışı ve buna paralel olarak yeraltı suyu kullanımının önemli miktarda artması, kıyı akiferlerinde tuzlanma tehlikesini de beraberinde getirmektedir. Bu durum bölgenin ekonomisini ve su kaynaklarının sürdürülebilirliğini etkilemektedir. Bu çalışmada, Karaburun Yarımadası'ndaki suların fiziksel ve çevresel izotop içerikleri birlikte değerlendirilerek, bölgedeki akiferlere ilişkin özellikler irdelenmiştir. Bu nedenle inceleme alanında yağışlı ve kurak dönemlerde suların fiziksel ve izotopik özellikleri için 26 noktada su numunesi alınmıştır. Elde edilen verilere göre inceleme alanındaki suların kurak dönemde elektriksel iletkenlik (Eİ) değerlerinin yükseldiği görülmüştür. Bu durum, kurak dönemde bölgedeki geçici nüfus artışı sebebiyle yeraltı suyu tüketiminin artışı ile ilişkilidir. Özellikle kıyı akiferlerinde aşırı su çekilmesi tuzlu su girişiminin artmasına sebep olmuştur. Kurak dönemde bazı kuyulardan alınan su numunelerinin (ILS gibi) trityum ve Eİ değerleri yüksektir
Citation - WoS: 18
Citation - Scopus: 21
Modeling of Seawater Intrusion in a Coastal Aquifer of Karaburun Peninsula, Western Turkey
(Springer Verlag, 2017-11) Mansour, Ahmed Y. S.; Gündüz, Orhan; Baba, Alper; Baba, Alper; Gündüz, Orhan; Şimşek, Celalettin; Elçi, Alper; Murathan, Alim; Sözbilir, Hasan; 03.07. Department of Environmental Engineering; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Seawater intrusion is a major problem to freshwater resources especially in coastal areas where fresh groundwater is surrounded and could be easily influenced by seawater. This study presents the development of a conceptual and numerical model for the coastal aquifer of Karareis region (Karaburun Peninsula) in the western part of Turkey. The study also presents the interpretation and the analysis of the time series data of groundwater levels recorded by data loggers. The SEAWAT model is used in this study to solve the density-dependent flow field and seawater intrusion in the coastal aquifer that is under excessive pumping particularly during summer months. The model was calibrated using the average values of a 1-year dataset and further verified by the average values of another year. Five potential scenarios were analyzed to understand the effects of pumping and climate change on groundwater levels and the extent of seawater intrusion in the next 10 years. The result of the analysis demonstrated high levels of electrical conductivity and chloride along the coastal part of the study area. As a result of the numerical model, seawater intrusion is simulated to move about 420 m toward the land in the next 10 years under “increased pumping” scenario, while a slight change in water level and TDS concentrations was observed in “climate change” scenario. Results also revealed that a reduction in the pumping rate from Karareis wells will be necessary to protect fresh groundwater from contamination by seawater.
Citation - WoS: 83
Citation - Scopus: 91
Source of Arsenic Based on Geological and Hydrogeochemical Properties of Geothermal Systems in Western Turkey
(Elsevier Ltd., 2012-12) Baba, Alper; Baba, Alper; Sözbilir, Hasan; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Turkey is an area of complex geology with active tectonics and high geothermal potential. Especially, the western part of Turkey is a region of abundant geothermal activity. Faults accommodating the deep circulation of hydrothermal fluids of meteoric origin are the primary means by which of geothermal systems are controlled in this region. Many of the thermal activities are related to the improved dilation on the ~E-W-strikes of the graben faults. This situation serves as a suitable environment for the presence of high levels of arsenic in geothermal water resources. The highest concentrations of naturally occurring aqueous arsenic (As) are found in certain types of geothermal waters, generally those related to major graben faults. In this regard, high arsenic concentrations in geothermal resources have been detected in Western Turkey, including but not limited to Biga Peninsulla, Gediz Graben, Kucuk, and Buyuk Menderes Graben with values ranging from 1 to 1419ppb in geothermal fluids. The thermal waters have surface temperatures of up to 100°C and reservoir temperatures range from 150 to 248°C in the Menderes Graben, from 120 to 287°C in the Gediz Graben, and from 153 to 174°C in Biga Peninsula. Hydrogeochemically, the Menderes graben and Gediz Graben thermal waters are of the Na-HCO3, Ca-HCO3, and Na-SO4 types, whereas some geothermal fluids such as those of Tuzla and Kestanbol in the Biga Peninsula, Çeşme, and Urla are of the Na-Cl type.
Structural Controls on Gülbahçe Geothermal System and Its Hydrogeochemical Properties (western Turkey)
(Muğla Sıtkı Koçman Üniversitesi, 2014) Uzelli, Taygun; Baba, Alper; Mungan, Gamze Gül; Uzelli, Taygun; Baba, Alper; Sözbilir, Hasan; 03.03. Department of Civil Engineering; 01.01. Units Affiliated to the Rectorate; 01. Izmir Institute of Technology; 03. Faculty of Engineering
Gülbahçe Geothermal Field (GGF) is located in eastern parts of the Karaburun Peninsula and is about 45 km away from the city of Izmir, Turkey. The stratigraphy around the GGF is represented by a Miocene volcano-sedimentary succession, including several sedimentary and volcanic units. These units overlie the basement rocks of the Karaburun Platform Carbonates and Bornova Flysch Zone which consists of carbonate blocks embedded in sandstone and mudstone alternations. GGF is located on the Gülbahçe Fault Zone, and are composed of series of NW-SE to NE-SW trending faults, extending from Sığacık Bay to Gülbahçe Bay. While most of the geothermal systems in western Turkey are controlled by normal faults, geothermal systems at the Gülbahçe are controlled by NE/NW-trending strike-slip faults and NE/NW-trending oblique-slip normal faults. An association of these active faults accommodating deep circulation of hydrothermal fluids of sea water origin is the primary control mechanisms of geothermal systems of Gülbahçe.