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Paleoseismic history of the Manisa fault zone, Western Anatolia

According to existing literature, the western segment of the Manisa Fault Zone is well known characterized; however, the eastern segment of it has rarely been addressed. To decipher the Holocene seismotectonic behavior of the eastern segment of Manisa Fault Zone, trench-based paleoseismological analyses for the first time were performed along with it. To constrain the timing and frequency of past earthquakes, and elapse time from the last activation using the optically stimulated luminescence (O

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  1. Turkish Journal of Earth Sciences Turkish J Earth Sci (2021) 30: 806-832 http://journals.tubitak.gov.tr/earth/ © TÜBİTAK Research Article doi:10.3906/yer-2109-3 Paleoseismic history of the Manisa fault zone, Western Anatolia 1 2,3 1,2 2, İsmail DURAN , Hasan SÖZBİLİR , Semih ESKİ , Mustafa SOFTA *, 4 5 5 Hüseyin UYTUN , Mehmet YÜKSEL , Mustafa TOPAKSU  1 The Graduate of Natural and Applied Sciences, Applied Geology, Dokuz Eylül University, İzmir, Turkey 2 Department of Geological Engineering, Faculty of Engineering, Dokuz Eylül University, İzmir, Turkey 3 Earthquake Research and Implementation Center of Dokuz Eylül University, İzmir, Turkey 4 Investment Monitoring and Coordination Directorate, İzmir Governorship, Manisa, Turkey 5 Department of Physics, Faculty of Arts-Sciences, Çukurova University, Adana, Turkey Received: 10.09.2021 Accepted/Published Online: 17.10.2021 Final Version: 30.10.2021 Abstract: The 45-km-long, E-W to NW-SE-striking Manisa Fault Zone, which constitutes the western section of the Gediz Graben, is characterized by a pure normal sense of motion with a minor strike-slip component. Even though there are numerous historical earthquakes have been listed in Western Anatolia Graben System, a few studies have been addressed on seismic sources of the earthquakes so far. According to existing literature, the western segment of the Manisa Fault Zone is well known characterized; however, the eastern segment of it has rarely been addressed. To decipher the Holocene seismotectonic behavior of the eastern segment of Manisa Fault Zone, trench-based paleoseismological analyses for the first time were performed along with it. To constrain the timing and frequency of past earthquakes, and elapse time from the last activation using the optically stimulated luminescence (OSL) and radiocarbon (14C) dating, we collected twenty-six colluvial and paleosol samples from the trenches. The obtained paleoseismic data show that (i) Manisa Fault Zone is responsible for six surface rupturing earthquakes since late Pleistocene-Holocene, which is occurred at 30.6 ± 8.8 ka (E1), 15.0 ± 5.0 ka (E2), 6.6 ± 1.3 ka (E3), 2.9 ± 1.3 ka (E4), 0.8 ± 0.4 ka (E5), and 0.1 ± 0.1 ka (E6), (ii) the recurrences interval of destructive earthquakes on Manisa Fault Zone was found between 0.95 kyr to 3.8 kyr for Holocene, and (iii) the elapsed time since the most recent surface ruptured earthquake on the Manisa Fault Zone is 159 year. Key words: Paleoseismology, active fault, Manisa Fault Zone, Gediz Graben, western Anatolia 1. Introduction Pleistocene-Early Holocene Emlakdere and Turgutlu The Western Anatolia Graben System (WAGS) (Arpat formations from the footwall rocks of Bornova Flysch and Bingöl, 1969; Bellier et al., 1997; Akyol and Karagöz, Zone of Late Cretaceous-Paleocene age and Neogene 2009; Foumelis et al., 2021) has been prone to numerous volcano-sedimentary units (Okay et al., 1996, Özkaymak earthquake activity since the historical periods due to and Sözbilir, 2012, Özkaymak et al., 2013), (Figure 2). convergence of the African and Eurasian plates and their E-W to NW-SE-striking Manisa Fault Zone (MFZ) is slab rollback and subduction phenomenon (Ergin et made up of two main fault segments at a total of 45 km al., 1967; Ambraseys and Finkel, 1995; Ambraseys and long (Emre et al., 2018). Even though previous studies are Jackson, 1998; Jolivet et al., 2013,2015; Başarır Baştürk et mostly concentrated on the western segment of MFZ to al., 2017), (Figure 1a). These earthquakes were produced explain Quaternary-Holocene characteristics (Özkaymak by many active faults scattered throughout the WAGS et al., 2011; Akçar et al., 2012), the studies regarding consisting of several major graben systems such as Gediz active tectonics and paleoseismology of the eastern Graben, Küçük Menderes Graben, and Büyük Menderes segment of MFZ aim to unravel the Quaternary activity, Graben (Dewey and Şengör, 1979; Şengör et al., 1984; and landscape evolution has so far been rarely addressed. Royden, 1993; Bozkurt, 2003; Jolivet and Brun; 2010; Emre According to Özkaymak et al’s. (2011) studies, the western et al., 2018). The southwestern rim of the Gediz Graben is segment is responsible for three paleo-earthquakes, which bounded by Manisa Fault Zone (Paton, 1992; Seyitoğlu and correspond to 926 AD, 1595 AD, or 1664 AD, with the Scott, 1996; Hakyemez et al., 1999; Bozkurt, 2003). Along most recent event in 1845 AD. In addition, Akçar et al. the mountain front, the Manisa Fault Zone separates the (2012) stated that two of the 17 AD, 926 AD, and 1845 * Correspondence: mustafa.softa@deu.edu.tr 806 This work is licensed under a Creative Commons Attribution 4.0 International License.
  2. DURAN et al. / Turkish J Earth Sci 24 O 28 O 32 O 36 O EXPLANATION Pre-M ocene bedrocks str ke-sl p fault Euras an plate Black Sea str ke-sl p fault Quaternary alluv um Bornova Flysch Zone Rocks obl que N normal fault normal fault Quaternary volcan c rocks Karaburun Belt submar ne faults 100 km reverse fault Ple stocene sed mentary rocks C clad c and Menderes Mass ve reverse fault detachment fault NAFZ M ddle - Upper M ocene volcan c rocks Holocene fault low angle metamorph c mass ves Anatol an plate normal fault M ocene sed mentary rocks Quaternary fault Western Anatol an r ver extent on Early - M ddle M ocene volcan c rocks Ged z Detachment Fault B settlement Plate mov e surface rapture Z probably Quaternary Fault or L neament T FZ İB EA İon an Sea 36 Akh sar O Ae Aegean ge o Sea ab an AR tr 2000 Ar S NL IN c y- n 0 (m) M AN T A Pl -2000 -4000 Cyprus Arc A Y OU M -4000 GÖ Med terranean Arab an Al ağa A Afr can plate plate LM AR M F gure 2 AR Foça MANİSA Ç A BASIN A Man sa Man L BA D K sa SI A Marmara A Fa Ğ Lake N R AB ult SPİLDAĞI Zo GEDİZ GRABEN UR ne Turgutlu Kl 38,5O Sal hl lk UN KEMALPAŞA BASIN Fau İzm r Ke lt malpaşa Fautl Gülbahçe Fault Zone İzm r Fault Alaşeh r PE NİFDAĞI t Fa u l NIN lca t BOZDAĞ ızı Faul Çeşme Urla ult R H SA SULA k ar Fa Ovacık D ağ MAHMUT IG İ h sar H İH M O U N TA I N t a K raz ul R aF ıl E Yağc zl Sefer F Bayındır Ödem ş Tu SE A E G E Torbalı KÜÇÜK MENDERES GRABEN A K N AR S Sığacık AC N E A Gulf müldür F AD Beydağ Gü 5 km AĞ B au 26.5 27 27.5 28 O O O O 28.5O O lt Figure 1. A) Map showing the location of the study area and the main tectonic lines in Turkey (Eski et al., 2020 adapted from Şengör et al., 1985; Barka, 1992; Bozkurt, 2001; Koçyiğit and Özacar, 2003. B) Regional-scale generalized geological map of the study area (Revised Eski et al., 2020 and adapted from; Bozkurt, 2001; Candan et al., 2011; Uzel et al., 2013; Özkaymak et al., 2013; Emre et al., 2018 and Tepe et al., 2021). AD earthquakes seem to have produced ruptures on the show that NE-SW trending strike-slip faults and NW-SE, Mugırtepe Fault scarp at the western segment of MFZ. NE-SW and E-W trending dip/oblique-slip normal faults To bridge the gap in the existing literature, we aimed are dominant in and around the study area. According to at the Holocene seismotectonic behavior of Manisa Fault the research, these faults were observed to work together Zone by trench-based paleoseismological surveys to and were found to be the source of both earthquakes of reveal (i) Pleistocene and Holocene earthquake activities, the instrumental period and earthquakes of the historical (ii) average recurrence interval, and (iii) elapsed period period (Taymaz et al., 1991; Akyol et al., 2006; Zhu et al., from the last earthquake by using optically stimulated 2006; Aktar et al., 2007; Tan et al., 2008; Sözbilir et al., luminescence (OSL) and radiocarbon (14C) dating 2008, 2009; Özkaymak et al., 2011; Uzel et al., 2012). methods. The earthquake magnitudes that these faults can generate vary from 6.3 to 6.9, starting from the Bergama 2. Seismotectonic setting Fault in the north to the Kemalpaşa Fault in the south, Western Anatolia is one of the most seismically active and vary from 5 km to 40 km in length (Emre et al., regions in the world (Şengör et al., 1985; Taymaz et 2018). The existence of earthquakes with a magnitude of al., 1991; Seyitoğlu and Scott, 1991; Pavlides, 1996; 6.0 that have occurred in and around Manisa in the last Papazachos and Papazachou, 1997; Altunel, 1999; Koçyiğit 10 years is an important indicator of the ongoing seismic et al., 1999; Bozkurt, 2001; Akyüz and Altunel, 2001; activity in the region, while a number of destructive Caputo et al., 2004; Pavlides and Caputo, 2004; Caputo earthquakes occured in historical periods (Soysal et al., and Helly, 2008; Akyol et al., 2006). The geological and 1981; Ambraseys, 2009; Başarır Baştürk et al., 2017), seismological studies carried out and continuing to date (Table 1). 807
  3. DURAN et al. / Turkish J Earth Sci There are more than five earthquakes listed in catalogs general tectonic situation of Turkey, showed the Manisa which are 17 AD, 926 AD, 1595 or 1664 AD, 1845 AD, Fault as a fault with the potential to produce earthquakes and 1862 AD earthquakes seriously affected the Manisa around Manisa city. Allen (1974) first defined the fault city (e.g., Ergin et al., 1967; Ambraseys and Finkel, 1995; planes of the Manisa Fault. The name Manisa Fault was Ambraseys and Jackson, 1998; Başarır Baştürk et al., first given by Hancock and Barka (1987). 2017). Although the historical earthquake catalogs well The Manisa Fault was divided into two segments reflect the damage dimension on the Manisa region, the according to Emre et al. (2018): the western and eastern seismic source of these earthquakes is still unclear. Of part of the fault was 35 and 26 km, respectively. These these earthquakes, some of these events were attributed to segments continue directly through the city center of MFZ, the some of them have not correlated with the fault Manisa (Figure 3). A few studies handled with paleostress zone. There is a questionable problem that is how relied evolution of the Manisa Fault Zone and its related on the historical catalogs which were prepared eyewitness structures in the literature (Bozkurt and Sözbilir, 2006; and uncertain location. However, in this study, according Özkaymak, 2012). Bozkurt and Sözbilir (2006) suggest that to paleoseismological trenches, robust dating results, and the fault is a reactivated structure that once functioned as statistical evaluation of events were used to generate the a sinistral strike-slip fault, then as a normal fault. The first event time interval. movement was formed by the formation of a short E-W One of the well-recorded earthquakes in Western compression period before the onset of the modern graben Anatolia is the earthquake AD 17. It was recorded that Plio-Quaternary (Bozkurt and Sözbilir, 2006). The second more than 10 settlements around the Manisa settlement movement has a large normal slip component combined were damaged by this earthquake (Ambraseys, 1988; Soysal with small strike-slip components, with the rake of the et al., 1981; Guidoboni et al., 1994; Özkaymak, 2012). slip lines averaging 83° and showing a NE-SW directed Another important earthquake is the AD 926. However, extension (Bozkurt and Sözbilir, 2006), (Figure 4). the records of this earthquake are quite limited. According In the study of Özkaymak et al (2011), the MFZ was to the paleoseismological studies conducted in the western divided into three segments. The western section consists part of the study area, it was found that the western part of fault segments with a length of 10 km between the of the fault was the source of the AD 1845 earthquake villages of Kayapınar and Akgedik and roughly trending (Özkaymak and Sözbilir, 2012). Another earthquake in NW-SE. The central part has a length of about 10 km the study area is the AD November 3, 1862, earthquake. with a W-E extension. The eastern segment runs NW- Records of this earthquake are also very limited. However, SE direction and has a length of 15 km. Özkaymak and based on earthquake catalogs, it was found that this Sözbilir (2012) calculated the annual slip rate for three earthquake, whose intensity was given as IX, coincided segments in their tectonic-geomorphological study on with a location between Turgutlu and Manisa. After the the MFZ. Accordingly, they mention that a displacement evaluation of the last 100 instrumental periods, a list of 50 of 0.1 mm/year, 0.3 mm/year, and 0.26 mm/year occurred earthquakes with magnitude greater than 3 from AFAD- on the western, central, and eastern segments, respectively. ERD1 and KOERI2 was obtained (Figure 3). 2.1. Manisa Fault Zone 3. Methodology The MFZ, which is one of the large-scale normal faults, 3.1. Paleoseismological studies developed under the influence of the extensional tectonic To define the paleoseismic activity of the MFZ, five trenches regime in Western Anatolia (Özkaymak and Sözbilir, were excavated on the eastern and western segment of the 2008, 2012; Özkaymak et al., 2011; 2013). The mapping of master fault, where there is a well-defined morphological the fault linearity was first made by Weismantel (1891). In expression of the fault scarps. While four trenches were the earthquake geography publication of Sieberg (1932), excavated in the NE-SW direction, one of these was the fault segments extending from Manisa to Alaşehir are excavated in the NW-SE direction with a total length of shown on the map. The Manisa Fault is shown on the map 145 m and a maximum depth and width of 4 m. After the of the earthquake catalog of Pınar and Lahn (1952). In cleaning trench walls, it was gridded with horizontal and his study of the geology of the northwest of the Manisa vertical strings spaced 1 m. According to McCalpin (2009), Mountain, Oğuz (1966) mapped a fault of approximately we described the exposed units labeled by numbers based 3 km long covering the west and east of the city center of on their microstratigraphic positions. Then, sedimentary Manisa. Ketin (1968), in his publication examining the boundaries and structural features were mapped in detail 1 AFAD-ERD (Ministry of Interior Disaster and Emergency Management Presidency) (2021). Recent Earthquakes in Turkey [online]. Website https:// deprem.afad.gov.tr/ddakatalogu [accessed 16 June 2021]. 2 KOERI (Boğaziçi University Kandilli Observatory and Earthquake Research Institute Regional Earthquake-Tsunami Monitoring Center) (2021). Recent Earthquakes in Turkey [online]. Website http://www.koeri.boun.edu.tr [accessed 16 June 2021]. 808
  4. DURAN et al. / Turkish J Earth Sci 520000 539000 558000 r MF R ve 4283000 Kum YF MANİSA HF Z Z KF Ged BASIN zR Yağcılar ver ÇALDAĞ HIGH Murad ye Güzelköy Koldere Emlakdere MANİSA N T-4 T-1, 2 fR Ged z R ver ver 4272000 MFZ T-5 T-3 F Tu aF GFZ Aşağıçoban sa K SPİLDAĞI HIGH GEDİZ GRABEN MF Z 4262000 N Sancaklıbozköy 2 km EXPLANATION late M ocene Karadağ Group Normal fault R ver Alluv um, alluv al fan Yuntdağı volcan c un t Str ke-sl p fault early-m ddle Qaternary depos ts Settlement M ocene Emlakdere Format on Kızıldere Group Probably or bur ed fault T-1 Trench s te Turgutlu Format on late Cretaceous- Bornova Flysch Zone Stream Paleocene Figure 2. Geological map of the study area and trench locations (Revised from Özkaymak et al., 2013; Özkaymak and Sözbilir, 2012). Abbreviations: MFZ, Manisa Fault Zone; HFZ, Halitpaşa Fault Zone; KaF, Karaçay Fault; TuF, Turgutalp Fault; GFZ, Gürle Fault Zone; MF, Maltepe Fault; KFZ, Kaleköy Fault Zone. with graph papers and photographs. Lastly, samples were The samples were prepared at the Dokuz Eylül collected for optically stimulated luminescence (OSL) and University (DEU) Sample Preparation Laboratory, and radiocarbon (14C) dating of event horizons. the mineral separation steps were completed according to 3.2. Dating methods the standard procedures described by Aitken (1998) and OSL and 14C dating methods are one of the states of Spencer and Robinson (2008). The following procedures arts and well-known techniques in paleoseismological were performed for equivalent dose (De) and annual studies (e.g., Fattahi and Walker, 2007; Preusser et al., dose measurement procedures. The measurements of 2008; Fattahi et al., 2010; Dogan et al., 2015; Ramsey et the OSL signals and its background and De estimations al., 2015; Stahl et al., 2016; Tsodoulos et al., 2016). To find were performed at Çukurova University TL/OSL Dating the timing of identified past earthquakes events related Laboratory. to MFZ, both OSL and 14C dating methods were used. The De’s of all quartz aliquots were determined using a While OSL dating has enabled to direct dating of wedge single aliquot regenerative (SAR) dose protocol (Murray and colluvium materials, 14C is mostly used paleo-soils and Wintle, 2000, 2003; Wintle and Murray, 2006) (see with having enough organic materials. Samples were taken Table 2). OSL signals were recorded using a lexsyg smart from the colluvial and wedges on the walls of the trenches. TL-OSL reader (developed by Freiberg Instruments, Twenty-five OSL samples and one radiocarbon sample Richter et al., 2015), equipped with a 90Sr/90Y beta source have collected the units and colluvial, wedges, and paleo- (dose rate: 0.10 Gy/s) and a Hamamatsu bi-alkaline soil levels. cathode photomultiplier tube (PMT). The stimulation 809
  5. DURAN et al. / Turkish J Earth Sci Table 1. List of historical earthquakes in the Manisa and surrounding area. Inten- Coordinate No Date Location References sity Lat– Long Manisa (Magnesia), Muradiye, Sart (Sardes), 38.40 – 27.50 Temnos, Myrina, Ephesus Appolania, Hyrcanis, VS 1, 2, 3, 4, 7, 1 AD 17 IX 38.5 – 27.8 Mastheni, Aegae, Hierocaesaria, Euthena, Ulloron, 8, 9, 10, 11 38.6168 – 27.3992 Philadelphia, Tmolus, Cyme, Thyatira, Gediz River, İzmir 2 AD 44 VIII 38.50 – 27.40 Magnesia, Ephesus 1, 2, 8, 9, 10, 11 3 AD August 8 926 VII 38.50 – 27.50 Manisa 7, 8, 9, 10, 11 4 AD September 1592 VIII 38.50 – 27.90 Turgutlu, Salihli, Manisa 2, 10, 11 Manisa, Urganlı, Sart, Ahmetli, Gedik, Bostancı, 5 AD September 22 1595 VII 38.50 – 27.90 5, 7, 8, 9, 10, 11 Hamza Çavuş, Azizli villages 6 AD June 2 1664 VII 38.41 – 27.20 İzmir, Manisa 1, 2, 5, 9, 10, 11 İzmir, Manisa (Magnesia), Turgutlu (Durgutli), 7 AD July 10 1688 X 38.40 – 27.20 2, 9, 11 Alaşehir (Philadephia) 8 AD September 1 1771 V 38.50 – 27.70 Aegean, Turgutlu 9, 11 9 AD September 27 1844 ? 38.61 – 27.42 Manisa region, İzmir 9, 11 VIII 1, 2, 6, 8, 9, 10 AD June 23 1845 38.60 – 27.50 Manisa region, İzmir IX 10, 11, 12 11 AD April 3 1850 VIII 38.40 – 27.45 İzmir, Kemalpaşa, Turgutlu 2, 11 Kemalpaşa, Manisa, İzmir, Aydın, Ödemiş, Tire, 12 AD April 20 1850 V 38.42 – 27.42 2, 9, 11 Bayındır 13 AD October 13 1850 VIII 38.40 – 27.20 İzmir, Manisa, Turgutlu, Ödemiş 2, 11 14 AD June 16 1858 VI 38.90 – 27.80 Manisa, Akhisar, İzmir 2, 9, 11 15 AD July 27 1859 ? 38.61 – 27.42 Manisa 9, 11 16 AD March 4 1860 V 38.61 – 27.42 Manisa 9, 11 17 AD November 3 1862 IX 38.40 – 27.70 Turgutlu - Manisa 2, 9, 11 18 AD August 18 1866 ? 38.61 – 27.42 Manisa 9, 11 19 AD November 10 1873 VI 38.92 – 27.83 Akhisar - Manisa 9, 11 References: (1) Ergin et al. (1967); (2) Soysal et al. (1981); (3) Ambraseys (1988); (4) Guidoboni et al. (1994); (5) Ambraseys and Finkel (1995); (6) Papazachos and Papazachou (1997); (7) Ambraseys and Jackson (1998); (8) Tan et al. (2008); (9) Ambraseys (2009); (10) Özkaymak et al. (2011); (11) Başarır Baştürk et al. (2017); (12) Papazachos and Papazachou (2003). AD: Anno domini. wavelength is 458 ± 5 nm (max. 100 mW/cm2 at sample Environmental radioactivity dose values were position) for the blue light stimulation. Detection of the determined at the laboratory of Mineral Research and OSL signals was achieved using the filter pack of BSL, TL- Exploration General Directorate (MTA), and the annual 365 nm (Hoya-U340-Glass-2,5 mm; Delta-BP 365/50 EX- dose values were calculated using U, Th, K ratios the Interference-5 mm). samples absorbed in a year. The luminescence dates were OSL decay curves and SAR dose recovery graphs calculated by dividing the De by the annual dose, according (corresponding sensitivity-corrected dose-response to Aitken’s (1998) equation. graph) for the selected ÇPA-3 sample are presented in A 14C sample taken from each trench for radiocarbon Figures 5a–5b. As seen in Figure 5 (b), the ratio of the test dating was meticulously collected from the paleo-soil level, to regenerative OSL, Lx/Tx, a sensitivity-corrected measure which contains charred wood fragments on the trench wall. of the OSL response shows the linear increment of Lx/ The collected sample was sent to the conventional carbon Tx with increased dose levels. The value of the R6/R1 rate dating laboratory in Kyiv. The obtained radiocarbon result equals 0.97 ± 0.04 for the ÇPA-3 sample, and it shows this was calibrated according to Reimer et al. (2013) with the linearity. help of the OxCal program of Ramsey and Lee (2013). 810
  6. DURAN et al. / Turkish J Earth Sci 530000 570000 4330000 6 SKFZ N Bergama Kırkağaç 22 5 km 12 GFZ BF 18 28 13 48 21 47 9 YUNTDAĞI 53 4 HIGH 46 Akh sar 19 49 AF 29 14 30 Ak 31 F 1 4290000 35 42 52 Saruhanlı GF Gölmarmara 39 38 Gö Ozanca 9 F 43 33 HF O 15 44 F MANİSA 16 18 10 32 1 M 45 FZ aF Tu F K SPILDAĞI HIGH 1 4 2 3 8 Turgutlu F Kemalpaşa GD İZMİR 12 1 4250000 KF 6 İF 7 13 11 17 Holocene Fault Normal fault 1900-2021 Instrumental Moment Earthquakes Mw ≥ 3 tensor Quaternary Fault Str ke-sl p fault 3 ≤ Mw ≤ 3.9 solut ouns 4 Probable-Quaternary 4 ≤ Mw ≤ 4.9 H stor cal Fault or L neament Low angle normal fault 5.1 ≤ Mw ≤ 5.5 earthquake locat ons Figure 3. Seismotectonic map of Manisa region. Yellow stars indicate historical earthquakes, and yellow, orange and red dots indicate epicentres of earthquakes greater than instrumental period M≥3. Earthquake data were taken from AFAD (ERD)1. (The faults are taken from the following studies; Özkaymak et al., 2011; Emre et al., 2018 and Eski et al., 2020). Abbreviations: (MFZ) Manisa Fault Zone; (İF) İzmir Fault; (KF) Kemalpaşa Fault; (GDF) Gediz Detachment Fault; (KaF) Karaçay Fault; (GF) Güzelhisar Fault; (HF) Halitpaşa Fault; (OZ) Ozanca Fault; (GöF) Gölmarmara Fault; (AkF) Akselendi Fault; (AF) Akhisar Fault; (GFZ) Gelenbe Fault Zone; (SKFZ) Soma- Kırkağaç Fault Zone; (BF) Bergama Fault. 811
  7. DURAN et al. / Turkish J Earth Sci E W b a d b c SE NW E W E W 76 63 65 d e f Figure 4. a-c indicates a close up view of the well-preserved Manisa Fault Zone. d-f; sub field views are showing the kinematic features that observed on the MFZ. Moreover, gathering the robust data, OSL and 14C dates randomly distributed limestone nodules. Overlaying unit were together refined by Bayesian methods in OxCal C represents light brown, matrix, and clast-supported, concerning historical earthquakes. medium sorted, angular slope breccia. It is noted that this unit is approximately 2 m. thrown (dip-slip) due to NE and 4. Findings SW trending faults. 4.1. Paleoseismological studies Previous units are overlaid by light brown, matrix- 4.1.1. Trench 1 supported, unsorted, gravel (Unit D), dark brown organic- Trench 1 was excavated on the eastern segment of MFZ. It rich clayey mud (Unit E), whitish-beige clast supported, was 33 m long and up to 3.5 m deep and wide. Both trench unsorted, angular gravel (Unit F), reddish-brown, walls have exposed eleven units with recent soil cover. The unsorted, muddy sandy angular gravel (Unit H), dark basement units consist of milky brown, unsorted, matrix- brown muddy gravel (Unit H), light brown medium sorted supported gravel (unit A), and greenish-brown unsorted, muddy gravel (Unit I), milky brown unsorted, angular matrix-supported gravel (unit B). It also includes gravel (Unit K). The observable vertical displacement 812
  8. DURAN et al. / Turkish J Earth Sci Table 2. Applied single aliquot regeneration (SAR) protocol for The earliest event occurred after deposition of unit G and quartz. before deposition of unit I. Hence, we collected OSL sample from the unit I (sample number ÇPÜ-4) representing the Step Treatment Observed upper boundary of the first event, which yielded a date of 6.56 ± 0.55 ka, and from the unit G (sample number ÇPÜ- 1 Preheat 220 C, 10 s o 3) representing the lower boundary of the first event, which 2 Stimulation with blue LED (125oC, 80 s) Ln yielded a date of 10.65 ± 1.41 ka. The final event cuts the 3 Give test dose unit I, so it occurred after deposition of unit I and before 4 Cut-heat TL (160oC, 5oC/s) deposition of unit K. Thus, the samples collected from the 5 Stimulation with blue LED (125oC, 80 s) Tn unit I yielded an OSL date of 6.56 ± 0.55 ka representing the lower boundary of the second event while the samples 6 Give dose Reg Point 1 collected from the overlying unit (unit K, ÇPÜ-1) yielded 7 Preheat 220oC, 10 s a date between 0.67 ± 0.49 ka. In addition, the small- 8 Stimulation with blue LED (125oC, 80 s) Lx scaled displacements observing in unit F and unit H could 9 Give test dose be considered to include post-seismic and/or creeping 10 Cut-heat TL (160oC, 5oC/s) motions in addition to the coseismic slip (Figure 6). 11 Stimulation with blue LED (125oC, 80 s) Tx 4.1.2. Trench 2 12 Return to Step 6 Trench 2 was located near Trench 1. It was excavated 34 m long, 3.5 m wide, and deep on the eastern segment of MFZ. Both trench walls have exposed ten units with recent soil cover. The basement unit (unit A) comprises light of Unit I is more than 2.5 m in between 29 m and 30 m brown, medium sorted cement supported angular gravels. of trench walls. Finally, unit L is characterized by beige Overlying unit B consist of whitish-beige unsorted cement gravelly recent soil cover (Figure 6). supported angular slope breccia. Unit A and Unit B are To constrain the timing of earthquakes, a total of five overlain by dark brown organic-rich clayey mud (Unit OSL samples were collected from Trench 1. The calculated B1), milky brown- beige unsorted, coarse gravel with fine dates are consistent with both stratigraphic orders in the gravels lenses (Unit C), reddish-brown unsorted cement trench walls. The derived dates of the samples from trench supported gravel (Unit D), light to dark brown organic- 1 were dated between 0.67 ± 0.49 ka and 24.98 ± 5.05 ka rich clayey mud (Unit H), dark brown, unsorted, muddy (Table 3). gravel with abrasion at some places (Unit E), dark brown, Based on the sedimentological, stratigraphic evidence angular limestone blocky gravelly mud (Unit F), dark the analysis of structural elements together with the results brown, fine to coarse gravelly mud (Unit G). In addition, of dated samples, two events were identified in this trench. unit C, unit D and unit G are evaluated as a colluvial wedge Figure 5. (a) Recorded OSL decay curves with blue light stimulation and (b) SAR dose recovery graphs of selected aliquot of quartz sample ÇPA-3. 813
  9. DURAN et al. / Turkish J Earth Sci 0 A MANİSA FAULT ZONE / ŞAHİNDERE-1 TRENCH (T-1) / WEST and EAST WALL B N F n sh coord nate: 541189/4272856 MANİSA N10E T-4 T-2 C MFZ 5 T-5 T-1 Start coord nate: 541184/4272821 T-3 D Aşağıçoban sa 10 0 Normal fault Str ke-sl p A E fault T-1 MFZ: Man sa Fault Zone MF Trench s te 15 Z B F 20 C 5 G 25 C H 30 33 D E1 B G I E K 10 I J A F 0 15 A H 20 G G B K 25 5 H I E2 30 ÇPÜ-H1-OSL-1 F 33 C E C 0.67 ± 0.49 ka D I D D 5 6 B E1 10 ÇPÜ-H1-OSL-4 J G K 6.56 ± 0.55 ka E I 0 4 F 15 WEST WALL A A 3 G H 20 ÇPÜ-H1-OSL-6 N G 24.98 ± 5.05 ka F EAST WALL 25 B H F I L E2 30 F 33 5 ÇPÜ-H1-OSL-3 E K 10.65 ± 1.41 ka 2 D C ÇPÜ-H1-OSL-5 I 12.15 ± 0.92 ka 1 I D J D 10 D E 15 F 20 G 25 30 H 33 I J UNIT LITHOLOGY EXPLANATION 14C - OSL DATE L Current so l Current so l r ch n brown colored organ c matter Gravel 0.67 ± 0.49 ka 1m K M lky brown color, poorly sorted, low strength, max. gravel of gra n s ze 12 cm Event II SCALE I Gravel L ght brown colored, long tud nal and rounded, poorly hardened, muddy gravel 6.56 ± 0.55 ka 1m H Gravel Dark brown pebbled mud substrate w th pebbles Event I G Sandy gravel Redd sh-brown colored angular, poorly hardened, poorly gra ned muddy sandy pebble 10.65 ± 1.41 ka Fault Data F Gravel Wh t sh-be ge color, gra n supported, locally supported mater al, very low strength, very poor textural matur ty, max.pebbles w th a gra n s ze of 13cm 12.15 ± 0.92 ka 1 N45W/63NE 2 N85W/52NE E Paleoso l Dark brown color paleoso l, r ch n organ c matter 3 N76W/69NE D Gravel L ght brown colored, low strength, poor he ght, med um rounded, max. gravel w th gra n s ze of 18 cm 24.98 ± 5.05 ka 4 N45W/71NE Slope brecc a 5 N70W/61NE C L ght brown colored, cement and ntermed ate supported, med um s zed slope brecc a 6 N70W/71NE B Gravel Gravel w th green sh-brown color, ntermed ate support, poor strength and textural matur ty C14-OSL A Gravel Pebbles w th m lky brown color, blocky, ntermed ate support, th n pebble lenses at t mes, very poor textural matur ty, low strength Sampl ng locat on Figure 6. Photomosaic and paleoseismological log of the trench 1. See explanation in text. Red dotted circles indicate OSL dating sample locations (The east wall is flipped). after the relevant earthquake events. It is noted that the calculated ages are consistent with both stratigraphic observable vertical displacement is more than 3 m in orders in the trench walls. The derived ages of the samples between 23 m and 26 m of trench walls. All these units from trench 2 was dated between 3.29 ± 0.14 ka and 54.46 are overlaid unconformably with light brown surface soil ± 3.07 ka (Table 3). (Unit I) (Figure 7). Based on the sedimentological, micro-stratigraphy We collected a total of six OSL samples from the walls evidence and results of dated samples, and the analysis of of trench 2 to constrain the timing of earthquakes. The structural elements, three events were detected in trench 814
  10. Table 3. Sample information, equivalent doses (De), dose rates data, and quartz OSL ages calculated for samples collected from the three trenches at MFZ. Dose-Rate Water Equivalent-Dose Grain Size 232 Altitude Depth Coordinate Study Area Sample No 238 Th 40 Content Age (ka) (µm) U (ppm) K (%) (m) (cm) (Decimal Degrees) De (Gr) (ppm) (%) ÇPÜ-1 150–250 3.0 8.0 1.04 12.20 124 35 38.6037O–27.4734O 1.6 ± 1.0 0.67 ± 0.49 ÇPÜ-3 150–250 3.7 8.1 1.12 5.12 124 220 38.6037O–27.4734O 27.8 ± 3.5 10.65 ± 1.41 O O ÇPÜ-4 150–250 1.3 9.6 1.20 5.94 124 95 38.6037 –27.4734 15.1 ± 1.1 6.56 ± 0.55 O O ÇPÜ-5 150–250 5.4 3.1 0.70 5.43 124 300 38.6037 –27.4734 27.8 ± 1.7 12.15 ± 0.92 TRENCH 1 ÇPÜ-6 150–250 2.6 3.2 1.75 3.81 124 200 38.6037O–27.4734O 43.3 ± 8.5 24.98 ± 5.05 O O ÇPA-1 150–250 2.9 10.5 1.12 7.95 85 70 38.6052 –27.4763 63.5 ± 4.1 24.94 ± 1.90 ÇPA-2 150–250 2.6 1.7 0.17 4.20 85 105 38.6052O–27.4763O 58.13 ± 0.51 54.46 ± 3.07 O O ÇPA-3 150–250 4.9 19.5 1.78 12.13 85 70 38.6052 -27.4763 37.63 ± 0.46 9.39 ± 0.37 ÇPA–4 150–250 2.2 2.4 0.42 2.75 85 100 38.6052O–27.4763O 57.11 ± 0.82 44.63 ± 2.44 O O ÇPA-5 150–250 3.0 22.6 2.08 16.24 85 100 38.6052 –27.4763 38.5 ± 1.8 9.91 ± 0.58 TRENCH 2 ÇPA-6 150–250 2.7 14.7 1.49 13.68 85 43 38.6052O–27.4763O 9.7 ± 0.2 3.29 ± 0.14 O O YH-2 150–250 1.7 9.6 1.13 6.07 62 80 38.5852 –27.5276 14.1 ± 2.3 6.21 ± 1.05 Manisa YH-4 150–250 1.4 6.2 0.91 4.40 62 125 38.5852O–27.5276O 3.9 ± 0.3 2.17 ± 0.2 O O YH-6 150–250 2.0 5.7 0.83 4.96 62 125 38.5852 –27.5276 12.67 ± 0.58 6.18 ± 0.3 O O YH-7 150–250 1.9 9.5 1.52 8.98 62 150 38.5852 –27.5276 11.4 ± 1.1 4.42 ± 0.46 DURAN et al. / Turkish J Earth Sci YH-X1 150–250 1.9 9.5 1.52 8.80 62 110 38.5852O–27.5276O 8.0 ± 0.7 3.09 ± 0.3 O O TRENCH 3 YH-X3 150–250 0.1 4.0 0.49 7.50 62 60 38.5852 –27.5276 6.2 ± 0.04 6.67 ± 0.35 MF-H2 150–250 0.6 20.8 2.70 9.57 81 155 38.6056O–27.4662O 28.6 ± 2.0 7.05 ± 0.28 O O MF-H3 150–250 0.7 18.4 2.62 5.99 81 250 38.6056 –27.4662 43.8 ± 2.8 11.01 ± 0.83 MF-H4 150–250 1.6 19.4 2.49 11.4 81 220 38.6056O–27.4662O 27.6 ± 1.4 7.06 ± 0.45 O O TRENCH 4 MF-H5 150–250 0.1 18.4 2.28 5.57 81 54 38.6056 –27.4662 4.5 ± 0.41 1.25 ± 0.13 GR-1 150–250 3.6 23.70 2.54 7.14 147 70 38.6057O–27.3646O 47.1 ± 1.9 9.61 ± 0.54 O O GR-2 150–250 3.2 21.90 2.67 5.50 147 61 38.6057 –27.3646 27.1 ± 4.7 5.53 ± 0.99 GR-3 150–250 1.9 16.30 1.94 4.97 147 25 38.6057O–27.3646O 2.4 ± 0.6 0.67 ± 0.17 O O TRENCH 5 GR-4 150–250 6.4 9.50 2.05 7.98 147 40 38.6057 –27.3646 14.0 ± 3.0 3.40 ± 0.74 815
  11. DURAN et al. / Turkish J Earth Sci SW 0 MANİSA FAULT ZONE / ŞAHİNDERE-2 TRENCH (T-2) / WEST and EAST WALL F n sh coord nate: 541495/4273096 N5E 5 N MANİSA T-4 T-2 Start coord nate: 541490/4273056 MFZ T-5 SW T-1 0 T-3 10 Aşağıçoban sa H B Normal fault Str ke-sl p fault C T-2 MFZ: Man sa Fault Zone MF Trench s te B 5 Z D 15 12 ÇPA-H1-OSL1 24.94 ± 1.9 ka E D SW E1 F 20 0 B 10 ÇPA-H1-OSL2 A 11 54.46 ± 3.07 ka C H G B B1 H B 25 C 15 5 13 C I D A 30 I NE J 10 34 SW E B I E 20 D 0 K ÇPA-H1-OSL3 9.39 ± 0.37 ka F 10 ÇPA-H1-OSL4 44.63 ± 2.44 ka L E2 25 E E3 7 C G M 9 6 30 H 5 B 15 8 G NE A N 34 5 I E 3 4 A E C O 20 J P E K 25 ÇPA-H1-OSL6 10 E3 3.29 ± 0.14 ka ÇPA-H1-OSL5 9.91 ± 0.58 ka WEST WALL L N C G 30 EAST WALL M 2 F NE 1 E 34 15 N C O 20 P 25 30 UNIT LITHOLOGY EXPLANATIONS 14C - OSL DATE I Current so l Current so l r ch n brown colored organ c matter NE H Gravel Colluv al r ch n dark-brown, poorly colored, organ c matter 34 G Colluv al wedge Dark brown colored mud, usually conta n ng l mestone gravel and blocks 3.29 ± 0.14 ka Event III F Mud Dark brown colored sludge conta n ng coarse gravel and blocks 9.91 ± 0.58 ka E Colluv al wedge Dark brown color, long tud nal, round bad and base abraded muddy gravel w th reverse grad ng 9.39 ± 0.37 ka from bottom contact and f ne gravel to coarse gravel 1m Event II Gravel Redd sh-brown colored, poor textural matur ty, med um strength and ntermed ate supported gravel 24.94 ± 1.9 ka Fault Data D (colluv al wedge) 7 N70E/73NW Event I SCALE 1 N55W/52NE 8 N89E/54NW C Coarse gravel M lky brown-be ge color, poor textural matur ty, coarse gravel w th med um gravel lenses 44.63 ± 2.44 ka 1m 2 N72E/63NW 9 N80E/59NW B1 Sand L ght brown colored paleoso l w th very poor strength 3 N66W/61NE 10 N85W/63NE Wh t sh-be ge colored, w th bad strength and textural matur ty, cement backed and ntermed ate add t ve, C14-OSL 4 N44W/64NE 11 N46E/70NW Gravel 54.46 ± 3.07 ka B max gra n length 18cm, avg. gravel w th gra n s ze of 5 cm Sampl ng 5 N78W/82NE 12 N65E/72NW A Coarse gravel L ght brown colored, med um long tud nal and rounded, coarse-gra ned gravel locat on 6 N25E/77NW 13 N55E/73NW Figure 7. Photomosaic and paleoseismological log of the trench 2. See explanation in text. Red dotted circles indicate OSL dating sample locations (The east wall is flipped). 2. The first event occurred after the deposition of unit C occurred after deposition of unit D and before deposition and before the deposition of unit D. So, to define the lower of unit E and Unit F. Thus, the samples collected from boundary of the first event, we collected the ÇPA-4 sample the unit D yielded an OSL date of 24.94 ± 1.90 ka (ÇPA- from unit C yielded a date of 44.63 ± 2.44 ka. The age 1) representing the lower boundary of the second event, result of unit D (ÇPA-1; 24.94 ± 1.90 ka) gives the upper while the samples collected from the overlying unit (unit boundary of the first event in trench 2. The second event E, ÇPÜ-3; unit F, ÇPA-5) yielded a date between 9.39 ± 816
  12. DURAN et al. / Turkish J Earth Sci 0.37 ka and 9.91 ± 0.58 ka. The final event occurred after YH-2) representing the upper boundary of the first event, deposition of unit F and before deposition of unit G. which yielded a date of 6.21 ± 1.05 ka and from unit C Hence, we collected OSL sample from the unit G (sample (sample number YH-3) representing the lower boundary number ÇPA-6) representing the upper boundary of the of the first event, which yielded a date of 6.67 ± 0.35 ka. first event, which yielded a date of 3.29 ± 0.14 ka and from The second event occurred after deposition of unit E and the unit F (sample number ÇPA-3) representing the lower before deposition of unit F. Thus, the samples collected boundary of the first event, which yielded a date of 9.39 ± from the unit E yielded an OSL date of 6.18 ± 0.30 ka 0.37 ka (Figure 7). (YH-6) representing the lower boundary of the second 4.1.3. Trench 3 event, while the samples collected from the overlying unit Trench 3 was excavated on the eastern segment of MFZ, (unit F, YH-7) yielded a date between 4.42 ± 0.46 ka. The and it was nearly 27 m long, 3.5m wide, and 4 m deep. penultimate event occurred after deposition of unit H The trench walls clearly show eleven different units with and before deposition of unit I. So, the samples collected recent soil. Brecciated limestone, which is belonging to from unit H yielded an OSL date of 2.17 ± 0.20 ka (YH- the hanging wall unit of the NE trending fault, forms the 4) representing the lower boundary of the second event basement unit (unit A) of the trench. This unit comprises while the samples collected from the overlying unit (unit I, of well strengthened unsorted limestone in various sizes RC-YH-1) yielded 175 ± 30 BP. The final event occurred in a light brown breccia. The basement unit is overlain after the deposition of unit I and before deposition unit J by dark brown colored limestone blocky gravel (unit B) Unfortunately, we could not find sufficient samples to date and reddish-brown, medium sorted muddy sandy gravel of upper the units J and K. On the other hand, this event (unit C). The observable vertical displacement is more must be occurred before the 175 ± 30 BP according to the than 1.5 m in between 17 m and 19 m of trench walls. radiocarbon date of the lower unit (unit I) (Figure 8). Overlying unit D consists of dark reddish-brown, unsorted 4.1.4. Trench 4 limestone gravelly muddy gravel. Nearly 2 m of the vertical Trench 4 was excavated on the eastern segment of MFZ, displacement is observed in between 4m and 6 m of trench and it was nearly 13 m long, 3.5 m wide, and 3 m deep. Both walls. These units are overlain by yellowish-beige organic trench walls have exposed nine units with recent soil cover. and pottery-rich clayey gravel (unit E) and dark brown, The basement unit (unit A) consists of a greenish dark unsorted, coarse gravel (unit F). The observable vertical grayish brown, deformed, and chaotic matrix, alternating displacement is more than 3.5 m in between –5 m and –1 with sandstone and mudstone. Overlying unit B represents m of trench walls. Overlying unit G consists of greenish- brown, medium strengthened sandstone blocky gravelly brown gravelly sandy mud, which is belonging to crack sand. Unit A and Unit B are overlain unconformably by fills. Overlying unit H consists of dark to orange, brown, brownish grey, poor sorted, blocky gravelly sandy mud well-sorted, upward fining muddy sandy gravel. Dark (Unit C), brownish beige gravelly muddy sand (Unit D), greenish brown organic-rich clayey silty mud represents yellowish reddish-brown pottery rich gravelly clayey mud unit I, and greyish-dark brown, poorly sorted silty clayey (Unit E), yellowish reddish-brown clayey mud (Unit F), gravel of unit J, respectively. In addition, unit J is colluvial reddish grey, brown muddy sand with pottery (Unit G), wedge after the final event. All these units are overlain reddish brownish medium strengthened gravely mud (Unit unconformably by light to dark brown surface soil with H) and finally, the unit I is characterized by beige gravelly silty clayey mud (unit K) (Figure 8). recent soil cover. The observable vertical displacement for To constrain the timing of earthquakes, a total of six Unit B and Unit G is 1 m in between 0 m and 2 m of trench OSL samples and one radiocarbon sample were collected walls (Figure 9). from Trench 3. The calculated dates are consistent with We collected a total of four OSL samples from the both stratigraphic orders in the trench walls. The derived walls of trench 4 to constrain the timing of earthquakes. ages of the samples from trench 3 was dated between 2.17 ± The calculated dates are consistent with both stratigraphic 0.20 ka and 6.67 ± 0.35 ka (Table 3). Also, the radiocarbon orders in the trench walls. The derived dates of the samples sample yielded 175 ± 30BP. Further, the calibrated date from trench 4 were dated between 1.25 ± 0.12 ka and for the radiocarbon sample was between 1725 calAD and 11.01 ± 0.83 ka (Table 3). 1815 calAD with a 95.4% probability (Table 4). Evaluation of Faulting Events Based on the sedimentological, micro-stratigraphy Based on the sedimentological, micro-stratigraphy evidence and results of dated samples, and the analysis evidence and results of dated samples and the analysis of of structural elements, four events were identified in structural elements, two events were identified in trench trench 3. The earliest event occurred after deposition 4. The first event occurred after deposition of unit E and of unit C and before deposition of unit D. Hence, we before deposition of unit F. Unfortunately, we did not gain collected OSL sample from the unit D (sample number certain age from Unit E and unit F due to a lack of quartz. 817
  13. DURAN et al. / Turkish J Earth Sci SW MANİSA FAULT ZONE / YARIKKAYA TRENCH (T-3) / WEST and EAST WALL F n sh coord nate: 545957/4270678 N MANİSA 0E N4 T-4 T-2 SW MFZ T-5 T-1 Start coord nate: 545928/4270647 T-3 0 Aşağıçoban sa Normal fault Str ke-sl p fault F Trench s te T-3 MFZ: Man sa Fault Zone MF 5 Z WEST WALL N A 10 SW EAST WALL 0 A 15 G 20 B NE 5 25 10 27 F C A D G YH-MF-OSL-x1 D E1 10 3.09 ± 0.3 ka 11 D 0 K E C E4 SW 12 G B E 15 F 20 YH-MF-OSL-1 14 1 A C:175 ± 30 BP YH-MF-OSL-2 J E3 25 I NE B 2 6.21 ± 1.05 ka H G 27 14 13 C D 5 E H H C A B H F G C F E D I 2 E1 YH-MF-OSL-x3 6.67 ± 0.35 ka C D 10 YH-MF-OSL-4 C E 2.17 ± 0.2 ka E4 3 15 4 B I 0 E F 20 5 K YH-MF-OSL-7 YH-MF-OSL-6 A C E3 4.42 ± 0.46 ka 6.18 ± 0.3 ka G 8 H J NE 6 25 B E H E2 27 H A 7 C H F 5 E C 9 I B 10 15 20 NE 25 27 UNIT LITHOLOGY EXPLANATIONS 14C - OSL DATE K Current so l Current so l r ch n brown colored organ c matter J Colluv al wedge Gray-colored, med um-tough, clayey gravel w th poorly rounded pebbles Event IV I Paleoso l Paleoso l r ch n organ c matter 175 ± 30 BP Fault data Event III H Gravel Dark brown-orange colored, poorly strengthened, partlywashed, well-graded, graded muddy pebbles w th a 2.17 ± 0.2 ka 1 N54W/37NE; 88SE t le-l ke arrangement. 2 N45W/64NE G Gravel Dark brown, very hard to harden, rough gravel w th textural matur ty 3.09 ± 0.3 ka 3 N64W/71NE Pottery 4 N39W/83NE F Gravel Fracture-crack f ll ng 4.42 ± 0.46 ka 5 N69E/44NW 1m Event II E Gravel Clay-colored pebble w th yellow sh-be ge color, med um-poor strength, and partly conta n ng organ c part cles. 6.18 ± 0.3 ka 6 N66W/73NE 7 N71W/68NE SCALE Muddy pebbles w th dark red color, poor strength, poor s ze, poorly rounded, 2mm and block-length l mestone D Gravel 6.21 ± 1.05 ka 8 N43W/52NE 1m pebbles Event I 9 N39W/78NE C Gravel Red-brown colored, h gh strength, poorly rounded, med um muddy-sandy gravel 6.67 ± 0.35 ka 10 N70W/81NE C14-OSL B Gravel Colluv al wedge made of dark brown colored angular l mestone block and coarse pebbles, not hardened, w th 11 N72E/44NW Sampl ng very poor strength. N76W/64NE locat on 12 Red brown colored, m ddleto poor strength, poor textural matur ty, poorly rounded, poorly rounded 2 mm A Fault brecc a to block-s zed l mestone pebbles, re nforced and cement t ous fault brecc a n places 13 N61E/63NW 14 N78E/58NW Old road Figure 8. Photomosaic and paleoseismological log of the trench 3. See explanation in text. Red dotted circles indicate OSL dating sample locations (The east wall is flipped). Table 4. Radiocarbon ages calculated from charcoal samples collected from the trench 3 at MFZ. Coordinate Trench name Sample no Age (BP) 2 sigma calibration (cal AD) (Decimal Degrees) 3 RC-YH-1 38.5852O–27.5276O 175 ± 30 1725–1815 818
  14. DURAN et al. / Turkish J Earth Sci SW MANİSA FAULT ZONE / KIRTIK TRENCH (T-4) / WEST and EAST WALL F n sh coord nate: 540441/4273206 0E 0 1 N3 2 3 4 Start coord nate: 540430/4273197 5 6 7 8 9 10 11 A 12 NE 13 B C SW 0 E2 1 2 3 4 5 6 7 I 8 9 10 11 H 12 J A D G NE 13 I B F E1 E H D B 4 A 5 E B C 6 B C A B SW MF-H1-2 WEST WALL 0 7.05 ± 0.28 ka E2 1 2 MF-H1-5 1.25 ± 0.13 ka N 3 4 EAST WALL I 5 6 7 A 8 D G 9 10 11 NE H 12 F 13 G D B F G A D F F D D B C E 2 1 3 C B C B B B SW MF-H1-3 MF-H1-4 11.01 ± 0.83 ka 7.06 ± 0.45 ka 0 1 2 3 4 5 6 7 8 NE 9 10 11 13 12 1m Fault Data 1 N70W/60NE 4 N60W/45NE SCALE 2 N85E/40NW 5 N40W/40NE Pottery 3 N65W/58NE 6 N55W/46NE 1m C14-OSL Sampl ng locat on UNIT LITHOLOGY EXPLANATIONS 14C - OSL DATE I Current so l Current so l r ch n brown colored organ c matter Event II H Gravelly mud Gray-colored, med um-strength pebbly mud 1.25 ± 0.13 ka N MANİSA G Muddy sand Gray colored, pottery p eces, th n pebbly muddy sand T-4 T-2 MFZ F Paleoso l Yellow sh-gray paleoso l T-5 Event I T-1 E Sand Pebbly muddy sand of gray color, low strength, poorly sorted, w th pottery fragments T-3 D Sandy mud Brown-be ge colored f ne-gra ned sandy mud w th low textural matur ty and strength. 7.05 ± 0.28 ka Aşağıçoban sa C Gravelly mud Th n pebbly mud of green sh brown color w th low textural matur ty and strength. 7.06 ± 0.45 ka Str ke-sl p Normal fault fault B Muddy sand Pebbled brown colored med um strength sandstone block 11.01 ± 0.83 ka T-4 Trench s te MFZ: Man sa Fault Zone MF A Sandstone- Green sh-dark gray-brown colored sandtone-mudstone, curved- rregular nner structure Z mudstone Figure 9. Photomosaic and paleoseismological log of the trench 4. See explanation in text. Red dotted circles indicate OSL dating sample locations (The east wall is flipped). 819
  15. DURAN et al. / Turkish J Earth Sci Instead of it, we dated Unit H and unit D to constrain the units are overlain unconformably by light to dark brown upper boundary and the lower boundary of the first event. surface soil with organic-rich silty clayey mud (Unit H) The obtained OSL dates were yielded 7.05 ± 0.28 ka, and (Figure 10). 1.25 ± 0.13 ka, respectively. The final event occurred after To constrain the timing of earthquakes, a total of four the deposition of unit H. Unfortunately, we could not find OSL samples were collected from trench 5. The calculated sufficient samples to date of upper the units I. On the other dates are consistent with both stratigraphic orders in the hand, this event must be occurred before the 1.25 ± 0.13 trench walls. The derived dates of the samples from trench ka according to the OSL date of the lower unit (unit H) 5 were dated between 0.67 ± 0.17 ka and 9.61 ± 0.54 ka (Figure 9). (Table 3). 4.1.5. Trench 5 Based on the sedimentological, micro-stratigraphy Trench 5 was excavated on the western segment of MFZ, evidence and results of dated samples, and the analysis and it was nearly 38 m long, 3.5 m wide, and deep. Both of structural elements, three events were identified in trench walls have exposed twenty-two units with recent soil trench 5. The first event occurred after deposition of unit cover. The basement units (unit A) consist of dark green, E1 and before deposition of unit E2. Hence, we collected poorly to moderate sorted, deformed, and chaotic matrix, OSL sample from the unit E2 (sample number GR-2) lenses alternating with sandstone and mudstone, greenish representing the upper boundary of the first event, which grey, poorly sorted, lower to moderate strengthened yielded a date of 5.53 ± 0.99 ka, and from the unit E1 quartzite gravels alternating with sandstone and mudstone (sample number GR-1) representing the lower boundary (unit A1), greenish grey, poorly sorted, lower to moderate of the first event, which yielded a date of 9.61 ± 0.54 ka. strengthened and alternating with sandstone and mudstone The second event took place before the deposition of unit (unit A2). Overlying units represent dark brown, lower F and after the deposition of unit E2. We collected both strengthened, organic-rich levels claystone (Unit B0), OSL samples from unit F (GR-4) and unit E2 (GR-2). brown, poorly sorted, lower strengthened angular gravelly The obtained OSL ages were yielded 3.40 ± 0.74 ka, and sandy claystone (Unit B), milky brown, poorly sorted, 5.53 ± 0.99 ka, respectively. The final event occurred after moderate strengthened cemented sandstone gravelly deposition of unit G0 and before deposition of unit G. sandy claystone (Unit B1), yellowish-brown, poorly sorted, Unfortunately, no datable material was found in Unit G0. moderate strengthened cemented sandstone gravelly sandy So, for defining the lower boundary of the final event, we claystone (Unit B2), milky brown and yellowish-brown, collected the GR-4 sample from the unit F yielded a date of poorly sorted, moderate strengthened cemented, sandy 3.40 ± 0.74 ka. The date result of unit G (GR-3; 0.67 ± 0.17 claystone (Unit B3). All of Unit A and Unit B are overlain ka) gives the upper boundary of the final event in trench unconformably by greenish-grey, poor sorted, lower to 5 (Figure 10). moderate strengthened well-folded clay (Unit C), greyish beige, lower to moderate strengthened, sandstone lenses, 5. Discussion and Conclusion sandy clay (Unit C1), reddish-brown, green, and brown, The E-W to NW-SE-striking Manisa Fault Zone (MFZ) lower to moderate strengthened, poorly cemented, clay is one of the sources of the significant earthquakes of the with fossil fragments (Unit C2), grey, lower to moderate Aegean region; it delimits the southern of the Manisa strengthened, altered whitish clay nodules (Unit C3), Basin. The zone is made up of two main fault segments, dark brown, lower to moderate strengthened, macrofossil and it is an active structure with distinctly observable fragment rich, folded silty clay (Unit D), greenish grey, north dipping fault scarps. To shed light on (i) Holocene- lower strengthened sandstone lenses, sandy clay (Unit D1). Quaternary paleoseismic activity of MFZ, (ii) the These units are overlain by yellowish-beige, poorly earthquake recurrence interval and elapse time since the sorted, lower to moderate strengthened and well-cemented last activity of fault, five trenches were excavated on the sandstone (Unit D2), greenish grey, lower strengthened, eastern and the western segments. Based on this research, poorly sorted sandstone and mudstone derived from the following assessments and discussions can be made. unit A1 and A2 (Unit E), orange, moderate cemented, Detailed studies of trench walls and dating studies and strengthened sand (Unit E1), greenish grey, lower signify that MFZ is responsible for at least four surface strengthened, poorly cemented sandy gravel (Unit E2). faulting earthquakes during the Holocene. All trenches Overlying unit F consists of dark brown, poorly cemented, were evaluated into the Oxcal program to generate events lower strengthened gravelly sandy mud, which is belonging interval using the Bayesian methods. According to the to a colluvial wedge. Overlying unit G0 consist of light plot, trenches excavated on the eastern segment (trench 1) brown sandy mud with an organic rich level. Overlying of MFZ provide evidence for two events after 10.65 ± 1.41 unit G consists of dark brown, gravelly sandy organic-rich ka. Paleoseismological evidence in trench 1 suggests that mud, which is belonging to a colluvial wedge. All these the first event took place sometime between 10.65 ± 1.41ka 820
  16. DURAN et al. / Turkish J Earth Sci and 6.56 ± 0.55 ka. Moreover, the final event took place earthquake catalogs and lower-upper age boundary and interval the 6.56 ± 0.55 ka and 0.67 ± 0.49 ka (Figure 11). its uncertainties, E2 corresponded with 17 AD or 926 Albeit, the E1 event has not been attributed to the exact AD earthquakes considering historical records (Table 5). earthquake due to the limited time interval of historical Further, more than 2.5 m vertical displacements observed SW 0 MANİSA FAULT ZONE / ANIT TRENCH (T-5) / WEST and EAST WALL 5 F n sh coord nate: 531744/4273113 N MANİSA N10E T-4 T-2 10 MFZ T-5 T-1 Start coord nate: 531733/4273073 T-3 15 Aşağıçoban sa Normal fault Str ke-sl p 20 fault Trench s te T-5 MFZ: Man sa Fault Zone MF SW 0 Z 25 A 30 5 A1 B 35 A A1 A1 E2 10 GIRIS-H1-OSL-2 NE 5.53 ± 0.99 ka GIRIS-H1-OSL-1 C 9.61 ± 0.54 ka 38 15 23 22 A1 E1 D A1 A A1 E1 20 E E2 A A2 E2 25 SW 26 24 A2 E 0 F GIRIS-H1-OSL-3 C3 C1 E3 30 0.67 ± 0.17 ka A2 27 29 B2 B2 GIRIS-H1-OSL-4 G 3.40 ± 0.74 ka C2 A 25 B2 5 C2 B2 B2 G 35 NE 38 31 A1 C 30 C B B1 32 B H 28 C A1 D D2 F E2 10 B B1 D1 F D2 C I A1 A1 15 34 SW A 33 D1 E1 A2 0 D 21 I J A 20 19 E1 E2 E A1 25 20 A2 WEST WALL A2 5 E F C 2 N A 18 B1 30 13 C1 10 12 17 G C2 15 14 16 11 10 EAST WALL C NE 9 8 B B1 B3 G 35 15 B0 H 6 B2 4 G0 38 5 7 20 3 D1 D2 I 2 D 1 25 J 30 35 NE 38 UNIT LITHOLOGY EXPLANATIONS 14C - OSL DATE H Current so l Current so l r ch n brown colored organ c matter BİRİM G Colluv al wedge Colluv al wedge w th brown colored mater al r ch n organ c matter 0.67 ± 0.17 ka Fault Data Event III 1 N43W/39SW G0 Paleoso l Brown sh paleoso l r ch n organ c matter 2 N45W/51NE F Colluv al wedge Colluv al wedge made of sandstone and mudstone gra ns n brown color, poor strength, poorly hardened 3.40 ± 0.74 ka 3 N41W/39SW; 48SE Event II 4 N52E/7SE E2 Sandy gravel Green sh-gray colored, poor strength, poorly hardened sandy pebbles made of sandy and muddy pebbles 5.53 ± 0.99 ka 5 N45E/68SW; 40SE Event I 6 N75E/35SE; 65NE E1 Sand Orange colored, med um strength, well-hardened sand 9.61 ± 0.54 ka 7 N57W/36SW E Sandstone- Green sh-gray colored, poor strength, poorly hardened, sandstone and mudstone der ved from A1 and A2 8 N63W/21SW; 58SE Foss ls mudstone 9 N61W/23SW; 60SE Sandstone w th yellow sh-be ge color, med um strength, poorly graded, well-hardened, alternat ng w th poorly D2 Sandstone gravelly pebbles. 10 N70W/34SW; 87NW 11 N23W/21SW; 58SE D1 Clay Green sh-gray colored, very poor strength, w th occas onally sandstone lenses, poorly hardened clast c clay Quartz te 12 N68W/32SW D Clay Dark brown colored s lty clay w th bad strength, med um harden ng, large foss l shells. 13 N60W/86SW 14 N55E/52SE; 78SW C3 Clay Wedge-shaped clay w th gray colored, poor strength, altered wh te tubers 15 N40W/52SW; 80SE 16 N40W/52SW; 58SE Claret red-red, occas onally green and colored, poor strength, occas onal foss l shells, poorly hardened and C2 Clay lateral trans t on w th sandstone. 17 N75E/38NW; 78NE Gray-be ge colored, very poorly strengthened, occas onally sandstone lenses conta n ng lenses, poorly 18 N55W/43NE C1 Sandy claystone re nforced clast c clay 19 N70W/41NE 1m C Clay Green sh-gray colored, poor strength, too much curved clay 20 N57W/81NE 21 N75E/87NW SCALE B3 Sandy claystone M lky brown and dark brown colored, med um-poor strength, well-consol dated, sandy claystone that 22 N68W/38NE 1m trans t ons from clast c to clay-dom nated med um from bottom to top. Claystone w th yellow sh brown color, med um strength, angular and textural matur ty w th poor sandstone 23 N25W/12SW B2 Claystone pebbles. 24 N40W/53NE C14-OSL B1 Claystone M lky brown colored sandy claystone w th med um strength, angular and poor textural matur ty, well-hardened, 25 N74W/58NE; 66SE Sampl ng locat on conta n ng sandstone pebbles. 26 N71W/39SW B Claystone Brown clay, sandy claystone w th med um-bad strength, angular and textural matur ty, w th sandstone gravels. 27 N85W/41SW; 71NW 28 N65E/43SE B0 Claystone Claystone n dark brown color w th very poor strength, close to the top contact w th carbon levels 29 N78W/14SW A2 Sandstone- The un t conta n ng green sh-gray color, med um-poor strength, poorly rounded sandstone and mudstone pebbles. 30 N48W/29SW; 58SE mudstone 31 N58W/27SW A1 Sandstone- Green sh-gray colored, med um-poor strength, un t w th poorly rounded sandstone and mudstone pebbles and 32 N42W/71NE mudstone quartz te pebbles 33 N74E/73NW Sandstone- Dark green color, med um to poor strength, sandstone and mudstone lens and block, conta n ng quartz te A mudstone pebbles. 34 N30W/66NE; 86SE Figure 10. Photomosaic and paleoseismological log of the trench 5. See explanation in text. Red dotted circles indicate OSL dating sample locations (The east wall is flipped). 821
  17. DURAN et al. / Turkish J Earth Sci OxCal v4.4.4 Bronk Ramsey (2021); r:5 Sequence Start NL_ÇPÜ-OSL-3 Boundary E1 NL_ÇPÜ-OSL-4 Boundary E2 NL_ÇPÜ-OSL-1 20000 15000 10000 5000 0 Modelled date (BP) Figure 11. Preferred model from OxCal v4.4.4 (Ramsey, 2008, 2009; Reimer et al., 2009) of timing constraints on earthquakes (E1-E2) at the trench 1 on the Manisa fault zone. Ages listed in sequence are in stratigraphic order, without depth constraints. on the fault, which are responsible for at least two events 0.28 ka (Figure 14). Detail paleoseismological evidence during the Quaternary period, were considered. in trench 4 suggests that the penultimate event took place Paleoseismic studies in trench 2 on the eastern sometime between 7.05 ± 0.56 ka and 1.25 ± 0.12 ka, which segment of MFZ indicate that the segment is responsible can be correlated with the 17 AD earthquake considering for three events after 44.63 ± 2.44 ka (Figure 12). Detailed historical records. The last event observed in this trench paleoseismological evidence in trench 2 suggests that on the eastern segment of MFZ best fit with the 926 AD while the three events were observed in this trench, earthquakes (Table 5). The first event has not correlated unfortunately, no historical earthquakes were recorded due with the catalogs due to the limited time interval. to the catalog’s time interval is limited (Table 5). According Moreover, the observed 1 m vertical displacement, which to the observed more than 3 m vertical displacements on may contain at least two events during the Holocene. the faults, this offset is believed to generate at least two or Trench data from trench 5 on the western segment three historical earthquakes that being surface rupture in of the MFZ, provide evidence for three events after 9.61 Pleistocene. ± 0.54 ka. The first event observed in the trench, there is Trench data from trench 3 on the eastern segment of no record of any large earthquake in the Manisa region the MFZ, provide evidence for four events after 6.67 ± between 9.61 ± 0.54 ka and 5.53 ± 0.99 ka (Figure 15). The 0.35 ka (Figure 13). Detailed paleoseismological evidence penultimate and last event observed in this trench on the in trench 3 suggests that the penultimate event took place western segment of MFZ best fit with the 17 AD and 926 sometime between 2.1 7 ± 0.2 ka and 175 ± 30 BP, which AD earthquakes, respectively (Table 5). can be correlated with the 926 AD earthquake considering Based on the well-constrained earthquake events historical records. The last event observed in this trench within the five trenches we assumed that six earthquake on the eastern segment of MFZ best fits with the 1862 cycles have occurred at 30.6 ± 8.8 ka (E1), 15.0 ± 5.0 ka AD earthquakes. Moreover, E1 and E2 events have not (E2), 6.6 ± 1.3 ka (E3), 2.9 ± 1.3 ka (E4), 0.8 ± 0.4 ka attributed to the exact earthquake due to the limited (E5), and 0.1 ± 0.1 ka (E6) (Figure 16), yields average time interval of historical earthquake catalogs (Table interevent times of 15.6 kyr between E1 and E2, 8.4 kyr 5). Considering the observed more than 3.5 m vertical between E2 and E3, 3.7 kyr between E3 and E4, 2.1 kyr displacements on the fault, this offset may contain at least between E4 and E5, and lastly, 0.7 kyr between E5 and E6. two earthquakes in Holocene. Moreover, considering the error parameter of ages, the Trench data from trench 4 on the eastern segment of interevent times could up to 29.4 kyr. While these values the MFZ, provide evidence for two events after 7.05 ± yield a closed holistically the recurrence interval ranging 822
  18. DURAN et al. / Turkish J Earth Sci Table 5. Event timing in T1, T2, T3, T4 and T5 trenches along the MFZ and corresponding earthquakes. %95.4-2 sigma-modelled Trench1-Event C_Earthquakes with Oxcal range from - to E1 7552 BC–2336 BC - E2 2289 BC– 1491 AD 17 AD, 926 AD Trench2-Event E1 37365 BC–19083 BC - E2 17579 BC–6327 BC - E3 5442 BC–1476 BC – Trench3-Event E1 4378 BC–2844 BC - E2 3440 BC–810 BC - E3 468 AD–1618 AD 926 AD E4 1860 AD–2007 AD 1862 AD Trench4-Event E1 3713 BC–71 AD 17 AD E2 983 AD–1417 AD 926 AD Trench5-Event E1 6552 BC–3040 BC - E2 2650 BC–166 AD 17 AD E3 800 AD–1772 AD 926 AD OxCal v4.4.4 Bronk Ramsey (2021); r:5 Sequence Start NL_ÇPA-OSL-4 Boundary E1 NL_ÇPA-OSL-1 Boundary E2 NL_ÇPA-OSL-5 NL_ÇPA-OSL-3 Boundary E3 NL_ÇPA-OSL-6 70000 60000 50000 40000 30000 20000 10000 0 Modelled date (BP) Figure 12. Preferred model from OxCal v4.4.2 (Ramsey, 2008, 2009; Reimer et al., 2009) of timing constraints on earthquakes (E1-E3) at the trench 2 on the Manisa fault zone. Ages listed in sequence are in stratigraphic order, without depth constraints. 823
  19. DURAN et al. / Turkish J Earth Sci OxCal v4.4.4 Bronk Ramsey (2021); r:5 Atmospher c data from Re mer et al (2020) Sequence Start NL_YH-OSL-X3 Boundary E1 NL_YH-OSL-2 NL_YH-OSL-6 Boundary E2 NL_YH-OSL-7 NL_YH-OSL-X1 NL_YH-OSL-4 Boundary E3 R_Date RC_YH-1 Boundary E4 14000 12000 10000 8000 6000 4000 2000 0 Modelled date (BP) Figure 13. Preferred model from OxCal v4.4.4 (Ramsey, 2008, 2009; Reimer et al., 2009) of timing constraints on earthquakes (E1-E4) at the trench 3 on the Manisa fault zone. Ages listed in sequence are in stratigraphic order, without depth constraints. OxCal v4.4.4 Bronk Ramsey (2021); r:5 Sequence Start NL_MF-H3 NL_MF-H2 Boundary E1 NL_MF-H5 Boundary E2 20000 15000 10000 5000 0 Modelled date (BP) Figure 14. Preferred model from OxCal v4.4.4 (Ramsey, 2008, 2009; Reimer et al., 2009) of timing constraints on earthquakes (E1-E2) at the trench 4 on the Manisa fault zone. Ages listed in sequence are in stratigraphic order, without depth constraints. 824
  20. DURAN et al. / Turkish J Earth Sci OxCal v4.4.4 Bronk Ramsey (2021); r:5 Sequence Start NL_GR-1 Boundary E1 NL_GR-2 Boundary E2 NL_GR-4 Boundary E3 NL_GR-3 16000 14000 12000 10000 8000 6000 4000 2000 0 -2000 Modelled date (BP) Figure 15. Preferred model from OxCal v4.4.2 (Ramsey, 2008, 2009; Reimer et al., 2009) of timing constraints on earthquakes (E1-E3) at the trench 5 on the Manisa fault zone. Ages listed in sequence are in stratigraphic order, without depth constraints. Table 6. Earthquake timing, interevent time, and recurrences interval in the eastern segment of Manisa Fault Zone. Interevent Time Recurrences Intervalb Dates I (kyr) R (kyr) A (ka) Ea (AEfirst-AEsecond) Imin Iaverage Imax RHolocene RPleistocene RHolistically Amin Aaverage Amax (AEmin- (AEaverage- (AEmax- AEmax) AEaverage) AEmin) Rmin Raverage Rmax Rmin Raverage Rmax Rmin Raverage Rmax E1 21.8P 30.6P 39.4P PE PE PE 1.8 15.6 29.5 E2 10.0H 15.0P 20.0P 2.1HE 8.4PE 14.7PE E3 5.3H 6.6H 7.9H 1.1HE 3.7HE 6.3HE 0.95 2.2 3.8 1.8 12.0 22.1 1.1 6.12 11.1 E4 1.6H 2.9H 4.2H 0.4 HE 2.1HE 3.8HE E5 0.4 H 0.8H 1.2H E6 0H 0.1H 0.2H 0.2HE 0.7HE 1.2HE : According to preferred model derived from Oxcal (Ramsey, 2008, 2009; Reimer et al., 2009). a b *: Represents recurrences interval based on the formula. The formula: Rmin: (AE1min-AE2max) +(AE2min-AE3max) +(AE3min-AE4max)/n-1 Raverage: (AE1average-AE2average) +(AE2average-AE3average) +(AE3average-AE4average)/n-1 Rmax: (AE1max-AE2min) +(AE2max-AE3min) +(AE3max-AE4min)/n-1 E: Events, N: number of events, H: Holocene, P: Pleistocene, HE: Holocene Event, PE: Pleistocene Event. 825
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