Geodinamica Acta最新文献

{"title":"8 January 2013 Mw = 5.7 North Aegean Sea earthquake and its seismotectonic significance","authors":"A. Kürçer, H. Yalçın, L. Gülen, D. Kalafat","doi":"10.1080/09853111.2014.957503","DOIUrl":"https://doi.org/10.1080/09853111.2014.957503","url":null,"abstract":"The deformation of the North Aegean Sea is mainly controlled by the westernmost segments of North Anatolian Fault System. On 8 January 2013, a moderate earthquake (Mw = 5.7) occurred in the North Aegean Sea. A series of aftershocks were occurred within four months following the mainshock, which have magnitudes varying from Ml = 0.9 to 5.0. We have obtained a total of 23 earthquake moment tensor solutions that belong to the 2013 earthquake sequence. The source of this earthquake sequence is a N75°E trending pure dextral strike-slip fault. The temporal and spatial distribution of the earthquakes indicate that the rupture unilaterally propagates from SW to NE. The stress tensor analysis shows that the direction of the regional compressive stress is WNW–ESE. The 1968 Aghios earthquake (Ms = 7.3) and the 2013 North Aegean Sea earthquake sequences indicate that the regional stress has been transferred from SW to NE in this region. The 1672 Bozcaada earthquake (M = 7.0) had been occurred to the north-east of the 2013 earthquake sequence. The elapsed time (342 year) and the regional stress transfer point out that the 1672 earthquake segment is probably a seismic gap and it is a potential earthquake hazard for this region.","PeriodicalId":50420,"journal":{"name":"Geodinamica Acta","volume":"2 1","pages":"175 - 188"},"PeriodicalIF":1.5,"publicationDate":"2015-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09853111.2014.957503","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59553200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitivity of seismic hazard results to alternative seismic source and magnitude-recurrence models: a case study for Jordan","authors":"N. Yilmaz, M. Yücemen","doi":"10.1080/09853111.2014.957506","DOIUrl":"https://doi.org/10.1080/09853111.2014.957506","url":null,"abstract":"Influence of different models and assumptions with respect to seismic source modelling and magnitude distribution on seismic hazard results is examined, taking Jordan as a case study. Four alternative models, which are based on different combinations of seismic source models and magnitude-recurrence relationships, are considered. Seismic hazard curves obtained at four different sites in Jordan according to these four models are compared. In order to display the magnitude of spatial variation of peak ground acceleration (PGA) values obtained from these models, difference maps for return periods of 475 and 2475 years are constructed. Logic tree method is applied to aggregate the results calculated based on different models and assumptions. Then, best estimate seismic hazard maps for PGA and spectral acceleration at 0.2 and 1.0 s corresponding to return periods of 475 and 2475 years are plotted.","PeriodicalId":50420,"journal":{"name":"Geodinamica Acta","volume":"31 1","pages":"189 - 202"},"PeriodicalIF":1.5,"publicationDate":"2015-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09853111.2014.957506","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59553861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early Eocene orthophragminids (Foraminifera) from the type-locality of Discocyclina ranikotensis Davies, 1927, Thal, NW Himalayas, Pakistan: insights into the orthophragminid palaeobiogeography","authors":"E. Özcan, M. Hanif, N. Ali, A. O. Yücel","doi":"10.1080/09853111.2015.1026795","DOIUrl":"https://doi.org/10.1080/09853111.2015.1026795","url":null,"abstract":"The study of isolated orthophragminid tests at the type-locality of Discocyclina ranikotensis Davies from the Patala Formation in Thal area (Upper Indus Basin, NW Pakistan) revealed new associations of genera Discocyclina Gümbel, and Orbitoclypeus Silvestri, not yet reported from eastern Tethys. We demonstrate that D. ranikotensis Davies, the species identity of which has been a subject of controversy in earlier works, is a valid species endemic at least to the Indo-Pakistan region. D. ranikotensis is associated with Discocyclina archiaci (Schlumberger), and very sparse Orbitoclypeus schopeni (Checchia-Rispoli), both species being key taxa for orthophragminid zonation in peri-Mediterranean Tethys. We have also identified a few discocyclinid specimens suggesting possible connection to western Tethys species D. fortisi, and a few specimens showing affinity to D. dispansa. The assemblages of orthophragminids suggest orthophragminid zone (OZ) 3 according to western Tethyan zonation scheme. The occurrence of D. archiaci extends the geographical distribution of this taxon to eastern Tethys, which hitherto was only known from peri-Mediterranean region. The typical western Tethyan asterocyclinids, nemkovellids and ribbed orbitoclypeids, first appearing at or around Paleocene/Eocene boundary (OZ 1B/2, SBZ4/5), have not been identified.","PeriodicalId":50420,"journal":{"name":"Geodinamica Acta","volume":"27 1","pages":"267 - 299"},"PeriodicalIF":1.5,"publicationDate":"2015-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09853111.2015.1026795","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59554159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Neoproterozoic granulite facies metamorphism in the Menderes Massif, Western Anatolia/Turkey: implication for the assembly of Gondwana","authors":"O. E. Koralay","doi":"10.1080/09853111.2015.1014987","DOIUrl":"https://doi.org/10.1080/09853111.2015.1014987","url":null,"abstract":"The Menderes Massif is a major polymetamorphic complex in Western Turkey. The late Neoproterozoic basement consists of partially migmatized paragneisses and metapelites in association with orthogneiss intrusions. Pelitic granulite, paragneiss and orthopyroxene-bearing orthogneiss (charnockite) of the basement series form the main granulite-facies lithologies. Charnockitic metagranodiorite and metatonalite are magnesian in composition and show calc-alkalic to alkali-calcic affinities. Nd and Sr isotope systematics indicate homogeneous crustal contamination. The zircons in charnockites contain featureless overgrowth and rim textures representing metamorphic growth on magmatic cores and inherited grains. Charnockites yield crytallization age of ~590 Ma for protoliths and they record granulite-facies overprint at ~ 580 Ma. These data indicate that the Menderes Massif records late Neoproterozoic magmatic and granulite-facies metamorphic events. Furthermore, the basement rocks have been overprinted by Eocene Barrovian-type Alpine metamorphism at ~42 Ma. The geochronological data and inferred latest Neoproterozoic–early Cambrian palaeogeographic setting for the Menderes Massif to the north of present-day Arabia indicate that the granulite-facies metamorphism in the Menderes Massif can be attributed to the Kuunga Orogen (600–500 Ma) causing the final amalgamation processes for northern part of the Gondwana.","PeriodicalId":50420,"journal":{"name":"Geodinamica Acta","volume":"27 1","pages":"244 - 266"},"PeriodicalIF":1.5,"publicationDate":"2015-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09853111.2015.1014987","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59554070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An overview on the main stratigraphic and structural features of a geothermal area: the case of Nazilli-Buharkent section of the Büyük Menderes Graben, SW Turkey","authors":"A. Koçyi̇ği̇t","doi":"10.1080/09853111.2014.957501","DOIUrl":"https://doi.org/10.1080/09853111.2014.957501","url":null,"abstract":"The study area is Nazilli-Buharkent section of the Büyük Menderes Graben. This is one of the most active intracontinental extensional structures shaping the south-western Anatolian graben–horst system, which comprises the southwestern frontal part of the Anatolian platelet. The Büyük Menderes Graben is about 3–30 km wide, 170 km long and approximately E–W-trending depression included in the back-arc section of the northerly-dipping south Aegean-Cyprian subduction zone. The Büyük Menderes Graben of episodic origin has two morphotectonic configurations: (1) a wider, uplifted, dissected and deformed initial configuration of late Early–late Middle Miocene age; and (2) the narrower, linear, undeformed and continuous recent configuration of Quaternary age. These two configurations are here termed as the Büyük Menderes palaeotectonic graben and the Büyük Menderes modern (neotectonic) graben, respectively. These two grabens are represented by two sedimentary packages separated by an intervening angular unconformity. The 1.1-km-thick older sedimentary package is deformed (steeply tilted to folded) and consists of, from bottom to top, unsorted boulder-block basal clastics and coal-bearing flood plain to lacustrine deposits of late Early–late Middle Miocene age. The younger sedimentary package is undeformed and consists of very thick (up to 0.9 km) debris flow and fluvial deposits of Quaternary age. The palaeotectonic configuration of the Büyük Menderes Graben is bounded by the Hasköy-Künüpe and İğdecik structural segments of the Büyük Menderes detachment fault. However, the modern configuration of the Büyük Menderes Graben is bounded by the Kuyucak and Menderes high-angle normal fault zones, composed of numerous fault segments, which cut and displace deeply the detachment fault. Hot water springs occur along the traces of the detachment faults. But they are not observed along the traces of modern graben-boundary faults. This reveals that the low-angle detachment fault is being still used by the geothermal fluids. Indeed, it is a fact that the geothermal fluids are shared by both the older detachment and younger high-angle normal faults at their intersection at depth, because the faults are the most suitable ways for the underground circulations of both cold meteoric waters and geothermal fluids, i.e. the geothermal system in south-western Turkey is fault-controlled. Consequently, the geothermal potential of this extensional domain is quite high based on the criteria such as the active tectonic and related faults, sources of high-heat, reservoir rocks with high porosity, reservoir cap rocks with no or low permeability and cold meteoric water supply enough. In order to obtain huge volume of geothermal fluids, first of all, whole steps of the geothermal exploration have to be completed, and then the site of borehole(s) has to be chosen so that it penetrates the intersection of low-angle detachment fault, high-angle normal fault(s) and the reservoir rocks over","PeriodicalId":50420,"journal":{"name":"Geodinamica Acta","volume":"19 1","pages":"109 - 85"},"PeriodicalIF":1.5,"publicationDate":"2015-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09853111.2014.957501","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59553407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of block rotations and the Curie Point Depths of magnetic sources along the NW–SE-trending Sülüklü–Cihanbeyli-Gölören and Şereflikoçhisar-Aksaray Fault Zones, Central Anatolia, Turkey","authors":"F. Bilim, A. Aydemir, A. Ateş","doi":"10.1080/09853111.2014.986873","DOIUrl":"https://doi.org/10.1080/09853111.2014.986873","url":null,"abstract":"The Şereflikoçhisar-Aksaray Fault (SAF) and Sülüklü–Cihanbeyli–Gölören Fault (SCGF) zones are located at the eastern and the western margins of the Salt Lake Basin-SLB (Tuzgölü Basin), central Anatolia, Turkey. These fault zones display intense magnetic anomalies along their trends and the positive amplitudes of these anomalies may reach up to 650 nT. In this paper, the body magnetisation directions are estimated from the selected five different magnetic anomalies with positive and negative peaks along these fault zones. Results of calculations indicated that local clockwise rotations are in the range of 34°E and 70°E. These magnetic anomalies were mainly created by the buried intrusive rocks. Locations of buried causative sources along the fault zones were determined from the analytic signal transformation of magnetic anomaly data. Curie Point Depths (CPDs) are also estimated from the aeromagnetic data to determine the thermal structure of the study area and they are correlated with the SAF and SCGF zones. It was found that the depth of magnetic crust varies from 11 to 22 km, consistent with the tectonic fault zones in the study area. The average value was determined as 16.7 km. These depths were correlated with the deep seismic reflection data and depths obtained from two windows in the seismic section, GTRS-87-801 are consistent with the CPDs. Shallow CPDs of magnetic sources are located along the SAF and SCGF to the east and west of the Lake Tuzgölü (Salt Lake) and it may be suggested that magnetic sources are probably located at the upper part of the crust.","PeriodicalId":50420,"journal":{"name":"Geodinamica Acta","volume":"27 1","pages":"203 - 213"},"PeriodicalIF":1.5,"publicationDate":"2015-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09853111.2014.986873","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59554285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence for the reactivation of a pre-existing zone of weakness and its contributions to the evolution of the Küçük Menderes Graben: a study on the Ephesus Fault, Western Anatolia, Turkey","authors":"Ökmen Sümer","doi":"10.1080/09853111.2014.986874","DOIUrl":"https://doi.org/10.1080/09853111.2014.986874","url":null,"abstract":"Detailed geological mapping at the western end of the Küçük Menderes Graben (KMG) in western Turkey reveals two main sedimentary packages separated by a regional unconformity: (1) Miocene units and (2) KMG basin-fill deposits of Quaternary age. The older basin-fill is represented by colluvial/alluvial fan facies association, which was controlled by a NW–SE-trending and SW-facing dip-slip normal fault (the Ortaburun Fault) and the conformably overlying fluvial and lacustrine deposits. The younger basin-fill, besides being characterised by lateral colluvial fan and axial river sediments deposited under the control of the Ephesus Fault, a southern basin-margin fault character, is also responsible for the evolution of the modern KMG. The analysis of structural, stratigraphic and sedimentological data indicates that three different deformation phases dominated during the Miocene to Recent time in the region: (i) during Early–Middle Miocene Phase 1 deformation (D1), the NW–SE-trending Ephesus Fault moved as a left-lateral strike-slip fault and occurred within the NE–SW-trending dextral shear zone of the İzmir-Balıkesir Transfer Zone (İBTZ) time; (ii) Middle Miocene Phase 2 deformation (D2) was associated with Ortaburun Fault, the northern basin-margin fault of the ancient basin. During this phase, the sinistral Ephesus Fault was reactivated as a dip-slip normal fault; and (iii) Phase 3 deformation (D3) was related with the formation of the KMG during the Quaternary and the Ephesus Fault forms the southern margin of the modern KMG. Structural evidence and computed palaeostress results show that the main extension direction during phase 1 and phase 3 has changed from north-west to north-east direction. This further suggests an approximately 60° rotation around the vertical axes and is attributed to the fact the region lies within the strike-slip dominated İBTZ.","PeriodicalId":50420,"journal":{"name":"Geodinamica Acta","volume":"27 1","pages":"130 - 154"},"PeriodicalIF":1.5,"publicationDate":"2015-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09853111.2014.986874","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59554356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Travertine occurrences along major strike-slip fault zones: structural, depositional and geochemical constraints from the Eastern Anatolian Fault System (EAFS), Turkey","authors":"Serap Çolak Erol, Mehmet Özkul, E. Aksoy, S. Kele, B. Ghaleb","doi":"10.1080/09853111.2014.979530","DOIUrl":"https://doi.org/10.1080/09853111.2014.979530","url":null,"abstract":"The Eastern Anatolian Fault System (EAFS) is a left-lateral strike-slip fault zone, 30 km wide and 700 km long, that is the second most important neotectonic structure of Turkey. In this study, relationship between travertine precipitation and tectonic activity of some segments along this major strike-slip fault zone has been investigated by a multidisciplinary research. Structural, sedimentological, geochemical and geochronological studies were conducted on several travertine occurrences along the Karlıova-Bingöl segment (KBS) and the Adıyaman Fault Zone (AFZ) of the EAFS. The Baltaşı travertine mass on the AFZ was cross-cut by many extensional fractures that were filled by calcite veins. Geochemical analyses of the calcite veins indicate that some are hydrothermal in origin, whereas others are non-hydrothermal. Hydrothermal circulation in the crust was caused intermittently by the left-lateral strike-slip movements that have oblique- to normal-slip components in both the (KBS) and the (BYS) segments. Our results suggest that, from at least 325 ka until present, tectonic activity was consistently accompanied by travertine deposition. Based on dating of the travertine occurrences in the valley of the Göynük Stream around Hacılar and Elmalı, it is concluded that the NE-trending KBS is currently still active.","PeriodicalId":50420,"journal":{"name":"Geodinamica Acta","volume":"27 1","pages":"155 - 174"},"PeriodicalIF":1.5,"publicationDate":"2015-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09853111.2014.979530","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59553871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geomorphic indices of rivers and drainage in China’s Longmen Shan Fault zone and their implications for regional tectonic activity","authors":"Zhenzhen Yan, Huai Zhang, Xiangtao Fan, Xiaoping Du","doi":"10.1080/09853111.2014.979533","DOIUrl":"https://doi.org/10.1080/09853111.2014.979533","url":null,"abstract":"Theoretical models suggest that active tectonic deformation can impose a primary control on the patterns and styles of channels. The Longmen Shan Fault zone, which is located on the eastern margin of the Tibetan Plateau, has experienced strong tectonic activity, including uplift and strike-slip phases of tectonic movements. Here, we adopt ASTER-GDEM2 data and utilise a stream-power incision model to extract information on the spatial characteristics of differential tectonic movements. Analysis of the patterns and styles of 37 channels exhibits systematic differences in the channel steepness indices and the river sinuosity values along the strike of the Longmen Shan Fault zone. Our primary results demonstrate that the normalised channel steepness indices in the southern part of the Longmen Shan Fault zone are much higher than those in the northern part, where the river sinuosity values are much lower. Comparisons between the five drainage basins reveal that the river systems in the middle southern part of the fault zone are mainly controlled by tectonic uplift and thrusting, whereas the river systems in the middle northern part of the fault zone are mostly attributed to right-lateral strike-slip movement.","PeriodicalId":50420,"journal":{"name":"Geodinamica Acta","volume":"2020 1","pages":"48 - 59"},"PeriodicalIF":1.5,"publicationDate":"2015-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09853111.2014.979533","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59554200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mixing of geothermal and non-geothermal fluids in shallow aquifers in the Germencik-Nazilli area, Büyük Menderes Basin (SW Turkey)","authors":"A. Bülbül","doi":"10.1080/09853111.2014.979529","DOIUrl":"https://doi.org/10.1080/09853111.2014.979529","url":null,"abstract":"This study observes groundwater hydrochemical characteristics during mixing between geothermal and non-geothermal fluids in Germencik–Nazilli area in the Büyük Menderes Basin (SW Turkey). Hydrogeochemical features of 32 non-geothermal, geothermal and surface samples were studied. The mean temperatures of the geothermal reservoirs are calculated to be 150–240 °C in Germencik field, based on Na-K-Mg geothermometry. Hydrochemical characteristics of Germencik geothermal fluid differ from non-geothermal fluids, mainly Na-Cl-HCO3-type geothermal fluid, while non-geothermal fluid is mostly Ca-Mg-HCO3-SO4 type. High contents of some minor elements in geothermal fluids are most likely sourced from prolonged water-rock interaction, reflecting the signals of flow paths and residence times. A mass-balance approach was used to calculate mixing ratios between geothermal and non-geothermal fluids based on B, Cl and Na concentrations. Germencik field is considerably characterised by rising geothermal fluids and overlying non-geothermal fluids. The amount of water stored in the Quaternary aquifer evolved from a deep thermal source is low in Germencik (.5–40% geothermal fluid in non-geothermal wells). Mixing between geothermal and non-geothermal fluids has been caused by groundwater utilisation practices and is increased close to active faults. Irrigation of the shallow groundwater composition is considered as influx of low-temperature geothermal fluid.","PeriodicalId":50420,"journal":{"name":"Geodinamica Acta","volume":"27 1","pages":"67 - 81"},"PeriodicalIF":1.5,"publicationDate":"2015-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09853111.2014.979529","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59553931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}