environmental bottom characterization required for modeling and prediction of high frequency acoustic bottomscattering modeling and prediction of acoustic bottom scattering require characterization of sediment geoacoustic and bottom roughness properties data from five recent shallow water acoustic experiments are presented on the temporal and spatial variability of values of those bottom parameters thought to be important to bottomscattering the importance of hydrodynamic and biological processes in controlling relevant sediment geoacoustic and roughness properties is also discussed an improved understanding of which physical scattering processes dominate bottom scattering at different frequencies beamwidths pulse lengths and grazing angles is required to predict bottomscattering from environmental properties work supported by norda

episodic graben formation and extensional neotectonic regime in west central anatolia and the isparta angle a case study in the aksehir afyon graben turkey

kinematic reconstructions and magmatic evolution illuminating crustal and mantle dynamics of the eastern mediterranean region since the late cretaceous the relationship between subduction dynamics and crustal deformation in the mediterranean region has been recently studied using three dimensional 3d numerical models such models require however a detailed information concerning the past geological evolution we use stratigraphic petrologic metamorphic structural paleomagnetic and magmatic data to build new kinematic reconstructions of the eastern mediterranean region since the late cretaceous using the principle of non rigid domains the motions of the 56 deforming domains defined in this work are calculated based on published paleomagnetic rotations the directions and amounts of displacement on crustal scale shear zones and the burial and exhumation histories of the main metamorphic units extracted from these reconstructions paleotectonic maps and lithospheric scale cross sections illustrate that the present day subduction zone has been continuously retreating southward since the late cretaceous and has accreted several small continental domains in the process we find evidence for two back arc related extensional events 1 slow extension along the balkans and the pontides in the late cretaceous while the trench was long and linear and 2 faster extension in the rhodope aegean west anatolian region since the eocene oligocene rapid rotation of the hellenides between 15 and 8 ma probably indicates a slab tearing event below western anatolia that could have further accelerated this extensional kinematics spatial distribution and the geochemical signature of magmatic centers integrated in these reconstructions allow us to trace mantle related processes revealing the deep dynamics that controls both the magma genesis and the crustal deformation

kinematics of a former oceanic plate of the neotethys revealed by deformation in the ulukisla basin turkey kinematic reconstruction of modern ocean basins shows that since pangea breakup a vast area in the neotethyan realm was lost to subduction here we develop a first order methodology to reconstruct the kinematic history of the lost plates of the neotethys using records of subducted plates accreted to former overriding plates combined with the kinematic analysis of overriding plate extension and shortening in cretaceous paleogene times most of anatolia formed a separate tectonic plate here termed anadolu plate that floored part of the neotethyan oceanic realm separated from eurasia and africa by subduction zones we study the sedimentary and structural history of the ulukisla basin turkey overlying relics of this plate to reconstruct the tectonic history of the oceanic plate and its surrounding trenches relative to africa and eurasia our results show that upper cretaceous oligocene sediments were deposited on the newly dated suprasubduction zone ophiolites 92 ma which are underlain by melanges metamorphosed and nonmetamorphosed oceanic and continental rocks derived from the african plate the ulukisla basin underwent latest cretaceous paleocene n s and e w extension until 56 ma following a short period of tectonic quiescence eo oligocene n s contraction formed the folded structure of the bolkar mountains as well as subordinate contractional structures within the basin we conceptually explain the transition from extension to quiescence to shortening as slowdown of the anadolu plate relative to the northward advancing africa anadolu trench resulting from collision of continental rocks accreted to anadolu with eurasia until the gradual demise of the anadolu eurasia subduction zone

new field and seismic data about the intraplate strike slip deformation in van region east anatolian plateau e turkey abstract the study area is the van earthquake region it is located in the western section of the east anatolian iranian plateau outside and to the east of the karliova triple junction based on the tectonic periods the rock units exposed in the study area are classified into two common categories these are the pre late pliocene paleotectonic units and the plio quaternary neotectonic units the paleotectonic units are composed of the yuksekova complex of campanian maastrichtian age and the kirkgecit formation of oligo miocene age the paleotectonic units are intensely deformed folded thrust to reverse faulted and converted into an imbricate stack the neotectonic units are composed of fluvio lacustrine sedimentary facies with volcanic interclations it is full of soft sedimentary structures such as deltaic structure slump fold sand dikes to sills and normal to reverse types of growth faults which imply to a sedimentation accompanied by both a volcanic activity and active tectonics originally the paleotectonic units are overlain with an angular unconformity by the nearly flat lying neotectonic units this angular unconformity and the big difference in the deformational patterns of both categories of rock units indicate an inversion in tectonic regime in late pliocene the new tectonic regime is the strike slip faulting dominated neotectonic regime it is governed by an approximately n s directed compression and composed of nw to ne trending strike slip faults n s trending oblique slip normal faults to fissures and the e w trending thrust to reverse faults most of thrust to reverse faults are inherited from the pre late pliocene paleotectonic regime some of them have reactivated and led to the occurrence of large and devastative earthquakes the last devastative seismic event is the 23 october 2011 tabanli van earthquake of mw 7 2 that caused 644 deaths and moderate to heavy damage of of structures 28 532 in van earthquake region the source of the tabanli earthquake is the everek erosional reverse fault in addition the tabanli earthquake is the largest seismic event occurred till now in turkey it was followed by a series over 6000 of small sized aftershocks and severeal moderate sized indepentent earthquakes of reverse normal and strike slip faulting origin both the field and new seismic data strongly reveal that the prominent tectonic regime in the east anatolian plateau is the strike slip neotectonic regime not the tensional tectonic regime as has been reported in some previous works the strike slip faulting and related deformation are confined into the upper shallowing part up to 40 km of the crust whilst the extensional deformations are the subcrustal processes and being taking place in a squashy zone at the depths of approximately 40 60 km

recent tectonics of east iranian azerbaijan from stress state reconstructions abstract iranian east azerbaijan e azerbaijan in northwestern iran is characterized by relatively complex active tectonics the area is shaped like a lozenge and is bordered by strike slip faults this region includes three fold and thrust belts the arasbaran ghoshe dagh and bozkosh mountain ranges and includes a set of n s trending compressive thrusts and folds and a set of e w trending compressive structures the stress inversion analysis and separation of stress tensors performed in this study indicate that the region is characterized by n s to ne sw n018 thrusting compression and nw se n287 and n155 strike slip compression the first stress system was responsible for the development of the three fold and thrust belts while the second system formed the n s striking structures such as those in the talesh salavat moro and kiamaki ranges the stress reconstructions indicate that e azerbaijan is colliding with the south caspian basin and the lesser caucasus in the ne and n due to the compressive stress s2 and with the central iranian block and western alborz in the southeast and east respectively due to the strike slip stress mode s3 and s1 respectively

analyses of fault mechanisms and expansion of southwestern anatolia since the late miocene abstract neotectonic field studies and detailed analyses of neogene and quaternary fault mechanisms in southwestern anatolia enable us to recognize a succession of compressional and extensional events and to characterize the direction of corresponding regional stresses the three most important compressive phases occurred during the miocene and a much smaller one near the plio quaternary boundary the last one or two interrupted a widespread extension of much greater duration and amplitude the whole tectonic evolution resembles that of the aegean the large extension by normal faulting is consistent with a minimum stress along a nne ssw average direction it appears that this direction was n s during the pliocene and changed to ne sw sometime during the quaternary this dominant nne ssw extension which began during late miocene or earliest pliocene was related to the development of the southwestern anatolian graben system

climate stability in central anatolia during the messinian salinity crisis abstract deposition of large amounts of evaporites and erosion of deep canyons within the mediterranean basin as a result of reduced basin connectivity with the atlantic ocean and the epicontinental paratethys sea characterized the messinian salinity crisis msc 5 97 5 33 ma the influence of the msc on mediterranean environmental conditions within the basin itself has been intensely studied from marine records but reconstructing the impact of the msc on circum mediterranean continental climate has been hampered by the absence of continuous sedimentary archives that span the duration of the event here we report results of a continental record of carbon 13c and oxygen 18o isotopes from lake carbonates framed by new magnetostratigraphic and 40ar 39ar dating as well as by existing mammal stratigraphy kangal basin central anatolia the sampled section records continuous fluvio lacustrine sedimentation from 6 6 ma to 4 9 ma which spans the msc and the miocene pliocene boundary this dataset so far represents the only continuous continental paleoenvironmental record of the msc in the circum mediterranean realm the kangal basin isotope record indicates a low degree of evaporation furthermore covariance between 13c and 18o suggests a coupling between lake water balance and biologic productivity variations in 13c and 18o therefore likely reflect changes in the amount of incoming precipitation rather than changes in 18o values of incoming precipitation the most prominent spike in 13c and 18o occurs during the acme of the msc and is therefore interpreted to have resulted from a decrease in the amount of incoming moisture correlative to a period of vigorous erosion and sea level lowering in the mediterranean basin major sea level lowering of mediterranean basin waters during the acme of the msc could have therefore led to slightly dryer conditions over anatolia which is also suggested by modeling studies overall changes in 13c and 18o values are small therefore we surmise that the msc had limited effects on the paleoenvironmental and paleoclimatic conditions in the anatolian interior

miocene transgression in the central and eastern parts of the sivas basin central anatolia turkey and the cenozoic palaeogeographical evolution we present here a reappraisal of the tectonic setting stratigraphy and palaeogeography of the central part of the sivas basin from palaeocene to late miocene the sivas basin is located in the collision zone between the pontides southern eurasia and anatolia a continental block rifted from gondwana the basin overlies ophiolites that were obducted onto anatolia from tethys to the north the central anatolian crystalline complex cacc experienced similar ophiolite obduction during campanian time followed by exhumation and thrusting onto previously emplaced units during maastrichtian time to the east crustal extension related to exhumation of the cacc created grabens during the early tertiary including the sivas basin the sivas basin underwent several tectonic events during paleogene neogene the basin fill varies with several sub basins each being characterised by a distinctive sequence especially during oligocene and miocene evaporite deposition in the central part of the basin during early oligocene was followed by mid late oligocene fluvio lacustrine deposition the weight of overlying fluvial sediments triggered salt tectonics and salt diapir formation lacustrine layers that are interbedded within the fluviatile sediments have locally yielded charophytes of late oligocene age emergent areas including the pre existing sivas basin and neighbouring areas were then flooded from the east by a shallow sea giving rise to a range of open marine sub basins coralgal reef barriers and subsiding restricted marine sub basins utilising new data from foraminifera molluscs corals and nannoplankton the age of the marine transgression is reassessed as aquitanian specifically age diagnostic nannoplankton assemblages of classical type occur at the base of the transgressive sequence however classical stratigraphic markers have not been found within the planktic foraminiferal assemblages even in the open marine settings in the restricted marine sediments there are rich planktic foraminiferal assemblages of classical type but these are of little use in stratigraphy in contrast the gastropod fauna indicate a burdigalian age sediment reworking in the restricted marine environments precludes stratigraphic determination in such environments micro and nano organisms experienced atypical developmental conditions the small benthic foraminifera and associated ostracod assemblages are good indicators of salinity which varied considerably within the restricted marine sub basins some of the corals within the coralgal reefs barriers are also dated as aquitanian a combination of the salt tectonics and the late miocene north westward verging thrusting created the present basin complexity

palaeomagnetic study of the karaman and karapinar volcanic complexes central turkey neotectonic rotation in the south central sector of the anatolian block abstract in the anatolian sector of the afro eurasian collision zone a palaeotectonic collisional phase paleocene to miocene responsible for emplacement of the pontide and tauride orogens has been replaced by a neotectonic phase of continental deformation late miocene early pliocene to recent the latter phase appears to have been accommodated mainly by crustal thickening during late miocene and pliocene times but was succeeded by complex differential rotations of fault blocks during crustal extrusion in late pliocene and quaternary times in this study we have investigated palaeomagnetism of miocene recent volcanic rocks comprising the western extension of the central anatolian volcanic province located in the south central part of the anatolian block with the aim of resolving deformations near to the border with the tauride orogen rock magnetic investigations identify low ti magnetite assemblages of primary cooling related origin these have predominant multidomain structures but significant fractions of single domains are always present low temperature alteration is largely absent the karaman volcanic complex late pliocene shows a net rotation of 5 7 6 9 not significantly different from the regional field axis during recent times the karapinar volcanic field brunhes epoch identifies a larger net rotation of 23 1 12 0 in a restricted sample the adjoining karacadag volcanic complex late miocene pliocene and middle miocene lavas beneath the hasandag complex define net rotations of 8 1 5 9 and 16 4 8 9 respectively analysis of palaeomagnetic results from late cretaceous recent rock units emplaced in anatolia during the palaeotectonic and neotectonic regimes shows that rates of rotation have accelerated in post pliocene times as crustal thickening has given way to tectonic escape a near uniform anticlockwise rotation of 25 35 has characterised much of this block during the most recent phase of deformation and appears to have occurred in common with the eurasian plate to the north of the north anatolian fault zone whilst this rotation appears to extend south eastwards across the ecemis fault zone towards the east anatolian fault the present study shows that smaller differential anticlockwise rotations have characterised the south central region of the block where it has interacted at its southwestern margin with oroclinal bending focussed on the isparta angle

tertiary evolution of the sivas basin central turkey abstract the sivas basin is one of several basins in turkey formed during closure of the northern branch of neotethys in early tertiary times cretaceous ophiolitic fragments and eocene platform carbonates and volcaniclastics transported northwards into the basin as olistoliths and grain flow aprons were incorporated into autochthonous eocene turbidites and bioclastic limestones the sequence as a whole was thrust northwards in late eocene times a southward sloping terrestial foreland basin related to northward directed thrusting developed during oligocene times a piggy back basin developed on top of this thrust system during the late oligocene the eocene thrusts were reactivated probably resulting in northward propagation of thrusts in the subsurface in early and mid miocene times the basin was floored by a thrust sheet which had been cut by n s trending tear faults or oblique culminations as a result of non uniform thrust advance in pre miocene times these n s faults were subsequently reactivated as extensional faults radial to the thrust front during early to mid miocene alluvial and shallow marine sedimentation later strike slip displacement along the n s faults was associated with the development of the northern boundary fault of the sivas basin in late miocene times which is regarded as a left lateral transpressive fault related to the north anatolian fault zone

the cilicia adana basin complex eastern mediterranean neogene evolution of an active fore arc basin in an obliquely convergent margin abstract detailed interpretation of multi channel seismic reflection profiles showed that the deposition of the miocene successions in the cilicia adana basin complex occurred within a foredeep south of the arcuate tauride fold thrust belt the misis kyrenia fault zone defined the northernmost of a number of smaller thrust culminations developed within this foredeep fluvio deltaic successions suggest that the adana and inner cilicia basins became emergent during the tortonian when the western portion of the piggy back basin retained a marine connection the entire region became emergent during the messinian salinity crisis and up to 1000 m of evaporites were deposited in the cilicia and southern adana basins stratigraphic and structural relationships demonstrated that the late plio quaternary cilicia adana basin complex evolved as an asymmetric piggy back basin on the hanging wall of the large south verging misis kyrenia thrust culmination on the misis kyrenia segment of the culmination thrust activity ceased in early messinian whereas on the kyrenia segment it continued to the present the shift in the kinematics is expressed by the development of the ne sw trending steep faults with extensional separations bounding the plio quaternary depocentre in the adana and inner cilicia basins these basement rooted faults are incompatible with the contractional regime that existed in this part of the basin complex during the miocene in the outer cilicia basin the incompatibility between a domain of continued south directed fold thrust activity and uplift on the kyrenia range and a domain of extension associated with the development of plio quaternary depocentre indicates that strain is strongly partitioned across the e w trending southern basin bounding fault system along the southern margin of the outer cilicia basin progressive westward displacement of the tauride block within the aegean anatolian microplate created a localised transtensional regime within the inner cilicia and adana basins suggesting the presence of hard intra plate fault boundaries centred along the misis kyrenia horst block and the southern basin bounding fault system the northern basin bounding fault system including the kozan fault in the cilicia basin is a set of large antithetic structures linked to the master faults the westward pull out of the tauride block is related to the overall westward escape of the aegean anatolian microplate during the latest miocene to early pliocene whereas the continued contraction south of the basin complex across cyprus is related to the evolving collision and under plating of the continental micro fragment the eratosthenes we propose that the southern master fault of the outer cilicia basin primarily functions as a boundary separating a contractional microplate domain to the south from a transtensional microplate domain to the north

evaluation of rock excavatability and slope stability along a segment of motorway pozanti turkey the ciftehan pozanti segment of the ankara pozanti motorway is problematic due to the existence of lithological units with variable character seven cut slopes are planned along km 358 000 km 364 350 of the proposed motorway the purpose of this study is to determine engineering geological properties of the rocks exposed along the motorway and to assess the excavatability and stability of the cut slopes both field and laboratory studies were carried out during this study field studies involved geological mapping detailed discontinuity surveying and sampling laboratory tests were carried out to determine unit weight point load strength index and shear strength parameters of the discontinuities in the study area recrystallized limestone microgabbro conglomerate and quaternary deposits are exposed however the cut slopes are located within microgabbro and conglomerate hard to very hard ripping with local blasting for the fresh inner part of the rocks is recommended for the excavatability in two cut slopes wedge failure is expected whereas in another two slopes both wedge and toppling failures are likely to occur based on the field observations and stability analyses of the cut slopes slope flattening with various angles wire mesh and drainage ditches are proposed

3 d crustal structure along the north anatolian fault zone in north central anatolia revealed by local earthquake tomography summary 3 d p wave velocity structure and vp vs variations in the crust along the north anatolian fault zone nafz in north central anatolia were investigated by the inversion of local p and s wave traveltimes to gain a better understanding of the seismological characteristics of the region the 3 d local earthquake tomography inversions included 5444 p and 3200 s wave readings obtained from 168 well located earthquakes between 2006 january and 2008 may dense ray coverage yields good resolution particularly in the central part of the study area the 3 d vp and vp vs tomographic images reveal clear correlations with both the surface geology and significant tectonic units in the region we observed the lower limit of the seismogenic zone for north central anatolia at 15 km depth final earthquake locations display a distributed pattern throughout the study area with most of the earthquakes occurring on the major splays of the nafz rather than its master strand we identify three major high velocity blocks in the mid crust separated by the izmir ankara erzincan suture and interpret these blocks to be continental basement fragments that were accreted onto the margin following the closure of neo tethyan ocean these basement blocks may have in part influenced the rupture propagations of the historical 1939 1942 and 1943 earthquakes in addition large variations in the vp vs ratio in the mid crust were observed and have been correlated with the varying fluid contents of the existing lithologies and related tectonic structures

development and morphometry of drainage network in volcanic terrain central anatolia turkey abstract this paper presents the results of morphotectonic and morphometric research carried out in order to determine the neotectonic development of the volcanic mountains and a drainage network in sw cappadocia the study area extends among the aksaray nigde and nevsehir provinces the study area comprises hasandag melendiz keciboyduran golludag mountains and the adjacent parts of these volcanic mountains data collected exclusively from 1 25 000 digitised topographic maps and 10 m resolution dems were used to define parameters related to the longitudinal profile of streams the study area was divided into 10 volcanic units longitudinal profiles of 20 streams and stream orders were analysed to determine a regional tectonic differentiation pattern in these units the streams in the study area drain into four different tectonic depressions these depressions are aksaray plain controlled by the tuz golu fault tgf ciftlik plain controlled by the keciboyduran melendiz fault kmf misli plain controlled by the derinkuyu fault df and bor plain controlled by the nigde fault zone nfz an analysis of morphometric parameters shows that the development of a drainage network is associated with faults and rock resistance occurrence of morphometric parameters with different values in units reveals that the volcanic mountains were not uplifted in the same period and were subjected to different morphologic processes high total order number in the south of hasandag unit 3 and melendiz mountains unit 7 indicate that the uplift ratio of the southern part is much greater than that of the northern part moreover development of the drainage network in the south is in a more advanced phase than in the north indeed the drainage network in the north is in the youngest erosional phase of all parts of the study area the increased stream length gradient indices sl and stream gradients and an analysis of headward erosion show that the streams displaying the longest and highest reach of the erosional phase are all in the southern part of keciboyduran and melendiz mountains the longitudinal profile lp of the present thalweg of the streams is irregular the irregular lp are associated with four different causes these are geological variations in resistance tectonics and volcanic topography and downcutting in response to stream incision the beginning of the fluvial incision in the northern part is younger than in the south

seismic velocity and poisson s ratio tomography of the crust beneath east anatolia abstract eastern anatolia is a region in the early stages of continent continent collision and so provides a unique opportunity to study the early development of continental plateau located within the alpine himalayan fold thrust fault belt the anatolian plateau is geologically very complex with over half of the surface area covered with late cenozoic volcanics of diverse composition the plateau is also seismically active and is dissected by numerous seismogenic faults predominantly of strike slip motion in this study we determine 3 d tomographic images of the crust beneath eastern anatolia by inverting a large number of arrival time data of p and s waves from the obtained p and s wave velocity models we estimated the poisson s ratio structures for a more reliable interpretation of the obtained velocity anomalies our tomographic results are generally consistent with the major tectonic features of the region high p and s wave velocity anomalies are recognized near the surface while at deeper crustal layers low seismic wave velocities are widely distributed poisson s ratio exhibits significant structural heterogeneities compared to the imaged velocity structure the seismic activity is intense along highly heterogeneous zones and is closely associated with pre existing faults in the central and western parts of the study area results of the checkerboard resolution test indicate that the imaged anomalies are reliable features down to a depth of about 40 km the low velocity high poisson s ratio zones in the middle to lower crust are consistent with many geophysical observations such as strong sn attenuation low pn and sn velocity and the absence of mantle lid implying the presence of partial melt in the uppermost mantle

active tectonics of the north and central aegean sea summary in this paper we examine the connection between the westward motion of turkey relative to europe and the extension in and around the aegean sea the principal new data available since the last attempt to synthesize the tectonics of this region by mckenzie 1978 are much improved focal mechanisms of earthquakes constrained by p and sh body wave modelling as well as by first motions these mechanisms show that the faulting in the western part of the aegean region is mostly extensional in nature on normal faults with a nw to wnw strike and with slip vectors directed nnw to nne there is evidence from palaeomagnetism that this western region rotates clockwise relative to stable europe in the central and eastern aegean and in nw turkey distributed right lateral strike slip is more prevalent on faults trending ne to ene and with slip vectors directed ne palaeomagnetic data in this eastern region is more ambiguous but consistent with very small or no rotations in the northern part and possibly anticlockwise rotations relative to europe in the south the strike slip faulting that enters the central aegean from the east appears to end abruptly in the sw against the nw trending normal faults of greece the kinematics of the deformation is controlled by three factors the westward motion of turkey relative to europe the continental collision between nw greece albania and the apulia adriatic platform in the west and the presence of the hellenic subduction zone to the south as the right lateral slip on the north anatolian fault enters the aegean region it splays out becoming distributed on several parallel faults the continental shortening in nw greece and albania does not allow the rotation of the western margin of the region to be rapid enough to accommodate this distributed e w right lateral shear and thus leads to e w shortening in the northern aegean which is compensated by n s extension as the southern aegean margin can move easily over the hellenic subduction zone the dynamics of the system once initiated is self sustaining being driven by the high topography in eastern turkey and by the roll back of the subducted slab beneath the southern aegean the geometry of the deformation resembles the behaviour of a system of broken slats attached to margins that rotate in spite of its extreme simplicity a simple model of such broken slats is able to reproduce quantitatively most of the features of the instantaneous velocity field in the aegean region including the slip vectors and nature of the faulting in the eastern and western parts the senses and approximate rates of rotation the overall extensional velocity across the aegean and the distribution of strain rates as seen in the seismicity and topography or bathymetry and using geodetic measurements as part of this study we re examined the relation between the surface faulting and the focal parameters determined seismologically for the three large 1981 gulf of corinth earthquakes and reassessed the evidence for associating particular earthquakes in the sequence with observed surface faulting an important result is that in one of the events there is a resolvable discrepancy between the slip vector measured at the surface and that determined from the seismic body waves

assessment of rock slope stability for a segment of the ankara pozanti motorway turkey abstract the ciftehan pozanti segment of the ankara pozanti motorway is problematic due to the existence of lithological units with variable characters ten cut slopes are planned along km 352 350 km 358 000 of the proposed motorway the purpose of this study is to determine engineering geological properties of the rocks exposed along the motorway and to assess excavatability and stability of the cut slopes both field and laboratory studies were carried out during this research field studies involved detailed discontinuity surveys laboratory tests were carried out to determine unit weight point load strength index and shear strength parameters of the discontinuities in the study area recrystallized limestone dolomite limestone microgabbro reefal limestone conglomerate and quaternary deposits are exposed however the cut slopes are located within microgabbro reefal limestone dolomite limestone and recrystallized limestone hard to extremely hard ripping with local blasting for the fresh inner part of the rocks is recommended for the excavatability in eight cut slopes wedge failure is expected based on the field observations and stability analyses of the cut slopes slope flattening with various angles wire mesh and drainage ditches are suggested

neogene tectonics and plate convergence in the eastern mediterranean new data from southern turkey data reported here demonstrate that the misis complex of southern turkey comprises a major olistostromic body formed prior to the early miocene and tectonically emplaced upon a structurally imbricated pile of deep and shallow marine sediments of early miocene to pliocene age magmatic rocks forming olistoliths in the misis complex have a back arc geochemical signature and variations in the facies paleoenvironments and paleotransport vectors within the associated sediments provide a record of miocene collisional events in southeast turkey the pseudo accretionary imbrication and structural style of the misis complex are attributed to continued collisional over thrusting but there is evidence within the imbricated stack of late sinistral strike slip faulting that relates to post miocene inception of motion along the east anatolian fault system the new data favor these geodynamic models proposed for the neogene evolution of the northeastern mediterranean that involve oblique convergence and associated strike slip adjustments

central and eastern anatolian crustal deformation rate and velocity fields derived from gps and earthquake data abstract we present a new strain rate and associated kinematic model for the eastern and central parts of turkey in the east a quasi n s compressional tectonic regime dominates the deformation field and is partitioned through the two major structural elements of the region which are the conjugate dextral strike slip north anatolian fault zone nafz and the sinistral strike slip east anatolian fault zone eafz the observed surface deformation is similar to that inferred by anisotropy studies which sampled the region of the mantle closer to the crust i e the lithospheric mantle and the moho and is dependent on the presence or absence of a lithospheric mantle and of the level of coupling between it and the overlaying crust the areas of the central and eastern parts of turkey which are deforming at elevated rates are situated above areas with strong gradients in crustal thickness this seems to indicate that these transition zones situated between thinner and thicker crusts promote more deformation at the surface the regions that reveal elevated strain rate values are 1 the elazig bingol segment of the eafz 2 the region around the karliova triple junction including the yedisu segment and the varto fault 3 the section of the nafz that extends from the erzincan province up to the nafz ezinepazari fault junction and 4 sections of the tuz golu fault zone other regions like the adana basin a significant part of the central anatolian fault zone cafz the aksaray and the ankara provinces are deforming at smaller but still considerable rates and therefore should be considered as areas well capable of producing damaging earthquakes between m 6 and 7 this study also reveals that the central part of turkey is moving at a faster rate towards the west than the eastern part turkey and that the wedge region between the nafz and the eafz accounts for the majority of the counter clockwise rotation between the eastern and the central parts of turkey this change in movement rate and direction could be the cause of the extensional deformation and respective crustal thinning with the resulting upwelling of warmer upper mantle observed in tomographic studies for the region between the iskenderun bay and the cafz the partitioning of deformation into an extensional regime could be the cause of the relatively low levels of strain rate in the south west part of the eafz and the northern part of the dead sea fault zone finally using this new compilation of gps data for the central eastern part of turkey we obtained a new anatolia eurasia rotation pole situated at 2 01 w and 31 94 n with a rotation rate of 1 053 0 015 ma

new kinematic and geochronologic evidence for the quaternary evolution of the central anatolian fault zone cafz as the kinematics of active faults that bound the anatolian plate are well studied it is now essential to improve our understanding of the style and rates of intraplate deformation to constrain regional strain partitioning and improve seismic risk assessments one of these internal structures the central anatolian fault zone cafz was originally defined as a regionally significant left lateral tectonic escape structure stretching for 700 km in a ne direction across the anatolian plate we provide new structural geomorphic and geochronologic data for several key segments within the central part of the cafz that suggest that the sinistral motion has been overstated the ecemis fault the southernmost part of the cafz has a late quaternary minimum slip rate of 1 1 0 4 mm a 1 slower than originally proposed farther north the erciyes fault has fed a linear array of monogenetic vents of the erciyes stratovolcano and 40ar 39ar dating shows a syneruptive stress field of ese wnw extension from 580 130 ka to 210 180 ka in the erciyes basin and central part of the cafz we mapped and recharacterized the erkilet and gesi faults as predominantly extensional these long term geological rates support recent gps observations that reveal ese wnw extension which we propose as the driver of faulting since 2 73 0 08 ma the slip rates and kinematics derived in this study are not typical of an escape tectonic structure the cafz is a transtensional fault system that reactivates paleotectonic structures and accommodates e w extension associated with the westward movement of anatolia

late pleistocene intraplate extension of the central anatolian plateau turkey inferences from cosmogenic exposure dating of alluvial fan landslide and moraine surfaces along the ecemis fault zone here we documented the vertical displacement slip rate extension rate and geochronology of normal faults within a narrow strip along the main strand of the ecemis fault zone the kartal cevizlik and lorut faults are normal faults that have evident surface expression within the strip terrestrial cosmogenic nuclide geochronology revealed that the kartal fault deformed the 104 2 16 5 ka aged alluvial fan surface and the cevizlik fault deformed the 21 9 1 8 ka old moraine and talus fan surfaces our topographic surveys indicated 120 10 m and 13 1 1 4 m surface breaking vertical displacements along the kartal and cevizlik faults respectively accordingly we suggest a 1 15 0 21 mm a 1 slip rate and 0 66 0 12 mm a 1 extension rate for the last 104 2 16 5 ka on the kartal fault and a 0 60 0 08 mm a 1 slip rate and 0 35 0 05 mm a 1 extension rate for the last 21 9 1 8 ka on the cevizlik fault we believe that these structures are an integral part of intraplate crustal deformation in the central anatolia they imply that intraplate structures such as the ecemis fault zone may change their mode through time presently the ecemis fault zone has been deformed predominantly by normal faults the presence of steep preserved fault scarps along the kartal cevizlik and lorut faults point to surface breaking normal faulting away from the main strand and particularly signify that these structures need to be taken into account for regional seismic hazard assessments

revealing the electrical properties of a gneiss dome using three dimensional magnetotellurics burial and exhumation cycles associated with faulting in central anatolia turkey abstract the nigde massif is a small scale exhumed lithospheric entity in central anatolia formed as a result of metamorphism driven by crustal thickening and migmatization its thermal and structural history records two burial and unroofing episodes induced by oblique tectonics related to an adjacent wrench zone of the ecemis fault to show the complex tectonic history of the events of this area its electrical resistivity structure was determined using three dimensional magnetotellurics forty seven high quality soundings within a frequency range of 320 hz 5000 s were utilized for this purpose the dimensionality of the data was investigated via phase tensor analyses and induction vectors a hydrothermal system that might be related to mt hasan was delineated as a widespread conductive zone in addition interpretation of the electrical resistivity models found a rheology seismicity relationship in the study area the nigde massif was depicted as a highly resistive dome like anomaly bounded by low angle detachment faults as indicated by the resistivity contrast between the massif and the adjacent features the lower boundary of the massif is defined by a resistive to conductive transition situated at 25 30 km depth beneath this transition a widespread low resistivity zone was interpreted as a partially melting lower crust this crustal feature is connected to a shallower anomaly beneath the ecemis fault zone which may infer the ascension of fluids that may be contributing to earthquake generation seismicity along the ecemis fault is overtly heterogeneous in that it tends to form a step approaching south along the fault where the lower crustal conductor is absent relevance between the seismicity and resistivity pattern denotes the presence of a fault configuration that is necessary for the yo yo tectonics

distributed neotectonic deformation in the anatolides of turkey a palaeomagnetic analysis abstract the palaeotectonic phase of deformation in anatolia accompanied closure of the tethyan ocean and was finally completed with sealing of the bitlis suture bordering the arabian shield at 12 ma arabia has since continued to indent the collage of terranes accreted to the eurasian margin by differential northward movement relative to africa along the dead sea fault zone and counterclockwise ccw rotation accompanying the opening of the red sea this neotectonic phase of deformation has accompanied uplift of the anatolian plateau and establishment of intracontinental transforms comprising the north and east anatolian fault zones deformation has included extrusion and rotation of blocks away from the arabian syntaxis by tectonic escape we produce an updated summary of palaeomagnetic results from this region to show that deformation has been distributed so that block rotations vary systematically across anatolia ranging from strongly ccw in the zone of high strain north of the arabian indenter to near zero in central anatolia and then progressively cw in western anatolia new palaeomagnetic results from the ankara igneous district are also reported and help to constrain the east to west change from ccw to cw rotation within central anatolia the transition of tectonic regimes from compression in the east to extension in the west involves the expulsion of blocks and their rotation along arcuate strike slip faults at an acute angle to the maximum compressive stress 1 between arabia and eurasia the comparable distribution of rotations in palaeotectonic and neotectonic units indicates that the bulk of the observed palaeomagnetic rotations have been concentrated within the last plio pleistocene phase of the neotectonic era as is found in the aegean domain to the west and has involved blocks of the order of 100 km in size the weak collage of accretionary terranes sandwiched between the arabian indenter and the eurasian margin now defined by the north anatolian fault zone has evidently taken up the bulk of the strain imparted by the continuing northward motion of arabia to expand the radius of the tauride arc and the perimeter of extruded crust bordering the limit of the extensional province in western turkey the distributed character of neotectonic deformation is illustrated by equivalent polar distributions both palaeotectonic and neotectonic palaeomagnetic poles show arcuate distributions with poles to best fitting small circles focussed close to the study area differences between the distributed neotectonic deformation resolved from palaeomagnetism and the contemporary gps record reflect the contrasting time periods being evaluated the palaeomagnetic record incorporates evolving and changing tectonic regimes whereas the gps signature has no long term validity within the weak anatolian collage hence the full spectrum of techniques for resolving neotectonic deformation is relevant to unravelling deformation in such regions

rift formation in the gokova region southwest anatolia implications for the opening of the aegean sea the time of the onset and the nature of the extension in the aegean area have been problematic owing to the confusion of neotectonic replacement structures with neotectonic revolutionary structures this paper concerns two rift systems of different ages and orientations in the gokova region of southwestern anatolia the first system has a northwest southeast trend with a middle to upper miocene infill whereas the second system is orientated in an east west direction and filled with plio quaternary rocks structural and palaeomagnetic data indicate that the first system originally had a north south trend and then bodily rotated anticlockwise to its present orientation before the end of the miocene both the orientations and the structural patterns of these cross cutting rift systems suggest that they resulted from two different and successive tectonic regimes regional geology suggests that the generative regime of the older system was characterized by north south compression and related to the palaeotectonic evolution of southwestern anatolia whereas that of the younger system is characterized by north south extension and relates to the neotectonic evolution of this region this inference contradicts at least in southwestern anatolia some recent claims that the extensional tectonics and the related rift formation in the aegean region began in the early miocene with the alleged demise of the compressional palaeotectonics during the late oligocene but is consistent with older views that placed the onset of north south extension into the later middle miocene the formation of the aegean sea seems to be the result of these two complicated and contrasting succesive tectonic regimes that have affected this region since middle miocene times

gps derived strain rate field within the boundary zones of the eurasian african and arabian plates we use the gps velocity field 1988 1998 for eastern mediterranean and asia minor to determine the crustal deformation strain rate field in an area bounded by 35 n and 43 n and 20 e and 48 e we calculate the normal and shear strain rate components associated with the major faults and compare these qualitatively with seismological data uncertainties in the calculation of the strain rates reach 50 nstrain yr 1 in sparsely observed parts of anatolia whereas we estimate errors 20 nstrain yr 1 in the aegean and marmara regions the largest compressional strain rate components in the eastern part of the study area occur along the greater caucasus mountain front reaching 70 nstrain yr 1 1 nstrain yr 1 0 0317 10 15 s 1 the north anatolian fault zone is the clearest feature in the shear strain rate field it is expressed as a pronounced dextral strike slip fault zone reaching rates of up to 170 nstrain yr 1 this holds true also for the izmit area where the august 17 1999 earthquake occurred central anatolia is almost strain free whereas extension prevails in western anatolia the principal axes of extension vary around the n s direction with strain rates of up to 85 nstrain yr 1 these extensional areas coincide with graben features and normal faulting earthquakes the central and southwestern aegean sea is strain free with values far below 40 nstrain yr 1 the seismic cluster around the dodekanissa islands southeastern aegean sea coincides with nw se oriented extension attaining strain rates of up to 90 nstrain yr 1 this area of extension also exhibits recent active volcanism the entire hellenic arc shows compressional strain rates perpendicular to the arc the pliny strabo troughs along the eastern segment of the arc show left lateral shear strain rates reaching 80 nstrain yr 1 significant extension is found in central greece with a nne ssw oriented maximum of 120 nstrain yr 1 centered around the gulf of corinthos the kephalonia fault zone in nw greece is a distinct dextral fault zone separating apulia from the rapidly moving aegean microplate right lateral shear strain rates reach 150 nstrain yr 1

paleomagnetic results along the bitlis zagros suture zone in se anatolia turkey implications for the activation of the dead sea fault zone abstract the tectonic evolution of se anatolia is associated with the collision between the taurides and the arabian platform in the early cenozoic after the final closure of the southern branch of the neotethys ocean during late cretaceous to early eocene times the ongoing deformation was characterized by northward movement of arabia followed by westward extrusion of anatolia having been displaced along the northern and eastern anatolian transform faults the neotectonic deformation history between the anatolian plate and the arabian platform since the closure of the southern neotethyan oceanic basin from late cretaceous to present has not been studied in detail paleomagnetically therefore we carried out a paleomagnetic study of mesozoic and cenozoic rocks at 34 localities along the bitlis zagros suture zone in se anatolia located in the boundary region between the taurides and the arabian platform and delimited by the dead sea fault paleomagnetic results from the area show clockwise rotations of 35 6 14 1 and 26 7 8 0 with respect to the african plate from upper jurassic lower cretaceous and upper cretaceous limestones respectively the paleomagnetic results indicate also an earlier deformation opening due to the dead sea fault zone dsfz farther north on the tauride block counterclockwise rotation of 34 5 12 5 is recorded by upper cretaceous limestones in the se of the study area on the northern margin of arabia however smaller counterclockwise rotations of 12 3 8 3 and 2 5 10 0 in late cretaceous and 12 7 13 6 in middle eocene rocks show relative tectonic stability middle miocene rocks close to the suture zone show counterclockwise rotation by about 39 4 10 9 while farther away from the suture zone counterclockwise rotations of 21 9 9 9 and 7 5 5 8 are observed paleolatitudinal motion from south to north from the late jurassic to the present is in concordance with the apparent polar wander path of eurasia and africa

review of the neotectonics of the eastern turkish armenian plateau by geomorphic analysis of digital elevation model imagery digital elevation model dem images provide synoptic views of the earth s surface allowing the analysis of landforms of still active tectonic and volcanic structures at regional scale a dem at 250 m pixel size constitutes regional scale data particularly efficient to investigate the late miocene quaternary deformation of the eastern turkish armenian plateau in the arabian eurasian area of convergence geomorphic analysis of the dem image associated with review of fault plane solutions of earthquakes show that faults are mostly strike slip with small vertical component here we show that the orientations of the tectonic and volcanic structures fit with a tectonic regime characterized by n s shortening and e w lengthening consistent with westward escape of anatolia perpendicular to the direction of the arabia eurasia shortening the uniform uplift of the plateau the predominance of strike slip faulting the lack of major thrusts and the occurrence of normal faults do not support a model of going on crustal thickening due to intracontinental convergence on the contrary our observations can be better interpreted in terms of lithospheric thinning and mantle upwelling related to gravity escape of anatolia

mantle flow induced crustal thinning in the area between the easternmost part of the anatolian plate and the arabian foreland e turkey deduced from the geological and geophysical data abstract eastern anatolia consisting of an amalgamation of fragments of oceanic and continental lithosphere is a current active intercontinental contractional zone that is still being squeezed and shortened between the arabian and eurasian plates this collisional and contractional zone is being accompanied by the tectonic escape of most of the anatolian plate to the west by major strike slip faulting on the right lateral north anatolian transform fault zone natfz and left lateral east anatolian transform fault zone eatfz which meet at karliova forming an east pointing cusp the present day crust in the area between the easternmost part of the anatolian plate and the arabian foreland gets thinner from north ca 44 km to south ca 36 km relative to its eastern eahp and western sides central anatolian region this thinner crustal area is characterized by shallow cpd 12 16 km very low pn velocities

the role of the early tertiary ulukisla basin southern turkey in suturing of the mesozoic tethys ocean the maastrichtian late eocene ulukisla basin is representative of the tectonic and sedimentary evolution of prominent early tertiary basins in central anatolia including the tuzgolu and arkisla basins the ulukisla basin overlies an ophiolitic melange of late cretaceous age between the bolkar carbonate platform to the south and the nigde kirsehir metamorphic massif to the north the basin stratigraphy records successive phases of transgression subsidence volcanism evaporite deposition deformation and uplift subsidence curves are consistent with an extensional or transtensional basin origin terminated by uplift the ulukisla basin includes a thick succession c 2 km of upper paleocene lower eocene basaltic to andesitic submarine pillow lavas lava flows volcaniclastic rocks and intercalated limestones whole rock xrf chemical analysis indicates a within plate origin with a marked subduction influence believed to be inherited rather than contemporaneous the ulukisla basin formed after late cretaceous ophiolite and melange emplacement and ended with late eocene emergence deformation and onset of oligo miocene non marine deposition we propose that late cretaceous ophiolite and melange emplacement reflect initial ocean basin closure this was followed by a long period c 30 ma of microcontinental adjustment including possible strike slip palaeorotation and suture tightening during which the early tertiary ulukisla basin developed possible driving forces were regional slab pull of a relict subduction zone or oblique diachronous convergence suture tightening was complete by late eocene time marked by collisional deformation and regional uplift

hydrothermal evolution of the copler porphyry epithermal au deposit erzincan province central eastern turkey the copler au deposit measured and indicated resource of 122 8 million tonnes at 1 7 g t au 4 8 g t ag and 0 1 wt cu is centered around shallow level dioritic to granodioritic intrusive rocks of the middle eocene copler kabatas magmatic complex which have been emplaced into a succession of regionally metamorphosed late paleozoic mesozoic sedimentary and carbonate rocks the deposit comprises a centrally located subeconomic porphyry cu au system characterized by a potassically altered biotite k feldspar magnetite core overprinted by a more extensive phyllic quartz sericite alteration zone the potassic alteration zone is associated with early m type hairline magnetite and crosscutting b type quartz magnetite sulfide veinlets whereas the enveloping phyllic altered rocks contain abundant d type quartz pyrite and lesser polymetallic quartz sulfide veinlets intermediate sulfidation epithermal au mineralization that overprints the porphyry occurred in two stages main stage epithermal mineralization is characterized by carbonate sulfide veinlets consisting of manganocalcite arsenical pyrite arsenopyrite marcasite chalcopyrite tennantite tetrahedrite galena and sphalerite late stage sooty pyrite veinlets contain some realgar and orpiment and are associated with zones of extensive carbonate alteration in the carbonate sulfide veinlets invisible gold is primarily hosted within arsenical pyrite and to a lesser extent by arsenopyrite tetrahedrite and tennantite in sooty pyrite veinlets invisible gold is associated with fine grained arsenical pyrite manto type carbonate replacement zones occur in the distal portions of the porphyry system and constitute a significant gold resource these carbonate replacement bodies display a mineral paragenesis similar to that of the epithermal carbonate sulfide veinlets in that they contain abundant arsenical pyrite together with lesser chalcopyrite arsenopyrite and marcasite and sparse sphalerite galena tennantite and tetrahedrite invisible gold in these ores is contained mainly within pyrite and chalcopyrite and to a lesser extent in arsenopyrite tetrahedrite and tennantite polyphase brine inclusions 47 62 wt nacl equiv in early b type quartz magnetite sulfide veinlets were trapped together with low salinity 3 5 5 wt nacl equiv vapor rich inclusions at temperatures 390 c and at a depth of 1 5 km under lithostatic conditions fluids associated with the overprinting phyllic alteration were slightly cooler 370 c and less saline 37 42 wt nacl equiv fluid inclusions in manganocalcite and sphalerite from epithermal carbonate sulfide veinlets trapped moderate salinity 4 15 wt nacl equiv fluids at 290 c whereas fluid inclusions hosted in barite and realgar from sooty pyrite veinlets were formed from low temperature 100 c and low to moderate salinity 1 14 wt nacl equiv fluids these data indicate that the au mineralizing system at copler progressed from a high temperature porphyry system to a relatively low temperature intermediate sulfidation epithermal system deposition of gold in the early stages of epithermal mineralization resulted from cooling sulfidation and neutralization of predominantly magmatic sourced hydrothermal fluids whereas a meteoric water component is evident in the latest stage of mineralization deposit scale geologic observations combined with fluid inclusion and stable isotope evidence suggest that mineralization at copler records activity of a relatively deep epithermal system and that its formation was structurally and lithologically controlled specifically the thick premineralization carbonate sequence once overlying the deposit acted as a pressure seal and also as a neutralizing agent during the build up of the magmatic hydrothermal system the weakening of this carbonate cover by igneous intrusion and subsequent hydrothermal activity may have contributed to later selective erosion of the alteration zone thereby telescoping the intermediate sulfidation epithermal system onto the earlier porphyry system and creating the copler window

a new intracontinental transcurrent structure the central anatolian fault zone turkey abstract recent neotectonic studies including remote sensing aerial photographs geological field mapping on various scales and measured stratigraphic section substantiate the existence of a large sinistral intracontinental transcurrent structure which we call the central anatolian fault zone cafz this is an approximately 730 km long 2 km to 80 km wide ne trending active sinistral strike slip fault zone that cuts across the anatolian plateau between duzyayla in the northeast and anamur county in the southwest it continues onward beneath the eastern mediterranean sea and determines the boundary of the antalya and adana basins as far as to the west of cyprus the cafz is a very young neotectonic structure it resulted from the reactivation and propagation of an older paleotectonic structure the so called ecemi s corridor in both nne and sw directions across the inner tauride suture in the plio quaternary times based on geometric discontinuities the cafz is divided into 24 segments each of them is characterized by a number of strike slip morphotectonic features reflecting recent motions the easternmost part of the anatolian platelet is being deformed internally by several dextral to sinistral intraplate strike slip faults these are the lake salt fault zone lsfz the salanda fault sf the cafz the goksu yazyurdu fault zone gyfz and the malatya ovacik fault zone mofz they take up lesser motion and are younger than boundary faults of the anatolian platelet the gyfz and mofz splay from the natf cut across the anatolian platelet and then meet to the eatf whereas other faults are confined into the anatolian platelet and seem to be independent structures however present day structural pattern of all these intraplate faults and boundary faults of the anatolian platelet indicates a regional strain pattern of nnw sse directed shortening and ene wsw directed extension and they seem to have developed to accommodate northward motion of the arabian plate since late early pliocene times

tectonic controls on metamorphism partial melting and intrusion timing and duration of regional metamorphism and magmatism in the nigde massif turkey protracted heating and melting of orogenic middle crust followed by emplacement of a syn extensional pluton during decompression and cooling are demonstrated for a metamorphic core complex in central turkey new geochronologic data for the nigde massif of the central anatolian crystalline complex document an interval of melting crystallization and pb loss at elevated ambient temperature 85 92 ma determined by u pb shrimp within a single sample of peraluminous granite crustal melting was syn to post peak metamorphism 725 c dated at 91 0 2 0 ma by shrimp analysis of zircon rims in sillimanite schist that is part of the country rock to the pluton metamorphic monazite in sillimanite schist yields a younger age of 84 7 0 7 ma for matrix grains and inclusions in garnet hornblende 40ar 39ar ages from amphibolites interlayered with the sillimanite schists coincide with the timing of emplacement of magma into metamorphic country rock that had experienced cooling and decompression to 12 km and 550 c the similarity of 40ar 39ar ages for biotite in the pluton 79 ma and hornblende 79 81 ma biotite 74 76 ma and muscovite 78 83 ma in the metamorphic country rock document rapid cooling 100 c my following intrusion the coincidence of the youngest u pb magmatic zircon ages and the oldest 40ar 39ar ages combined with structural evidence for normal sense shearing and tectonic unroofing in the late cretaceous suggests that intrusion was driven by extension we propose that crustal melting occurred in the middle crust during prograde metamorphism and or initial decompression and that ascent and emplacement of magma as a pluton were only triggered once extension occurred and removed upper crustal rocks

a probabilistic assessment of the seismic hazard in turkey abstract seismic hazard maps for turkey are developed by utilizing the current probabilistic procedures the maps contain probabilistic estimates of the maximum msk intensity and the maximum horizontal peak ground acceleration for the return periods of 225 475 and 10 000 years a modified and updated catalogue for the large and damaging earthquakes affecting turkey has been prepared to provide a base for the spatial correlation of the seismic activity with the geo tectonic elements brief descriptions of the seismic sources adopted for turkey for the purpose of seismic source regionalization are given recurrence relationship regression constants maximum magnitudes and intensity attenuation relationships are provided for each seismic source zone the earthquake phenomenon is based on both the point source model and the fault rupture model depending on the source model the results are discussed in detail the study is intended to serve as a reference for more advanced approaches and to stimulate discussion and suggestions on the data base assumptions and the inputs and to pave the path for the risk based assessment of the seismic hazard in the site selection and the design of nuclear power plants and in the design of common buildings and engineering facilities

effects of margin parallel shortening and density contrasts on back arc extension during subduction experimental insights and possible application to anatolia so as to investigate the parameters influencing subduction and back arc extension we have done three series of laboratory experiments 32 in all on physical models each model consisted of adjacent oceanic and continental plates floating on an asthenosphere in experiments of series a a wide rigid piston moving horizontally controlled the rate of convergence of the oceanic and continental plates whereas in series b or c a wide or narrow piston produced lateral compression parallel to the continent ocean boundary cob and perpendicular to the subduction direction the parameters that we tested were 1 the velocity of plate convergence series a 2 the width of the compressing piston series b and c and 3 the density ratio between oceanic and continental plates series b and c this density ratio was a key factor for a ratio of 1 4 the amount of extension in the continental plate increased regularly throughout time for a ratio of 1 3 the extension remained small until the piston stopped moving laterally and for a ratio of 1 1 there was little or no extension the width of the compressing piston had a smaller effect although a narrow piston provided more space into which the continental plate could extend one possible application of our models is to anatolia despite similar geological settings the areas north of the hellenic and cyprus subduction zones differ in that extension is large in the former and much smaller in the latter we suggest that one of the main driving forces for aegean extension may have been a high density ratio between subducting oceanic lithosphere and a hellenic balkanic upper plate

modeling of seismic hazard for turkey using the recent neotectonic data abstract recent developments in the neotectonic framework of turkey introduced new tectonic elements necessitating the reconstruction of turkey s seismic hazard map in this regard 14 seismic source zones were delineated maximum earthquake magnitudes for each seismic zones were determined using the fault rupture length approximation regression coefficients of the earthquake magnitude frequency relationships for the seismic zones were compiled mostly from earlier works along with these data a strong ground motion attenuation relationship developed by joyner and boore joyner w b boore d m 1988 measurement characterization and prediction of strong ground motion earthquake engineering and soil dynamics 2 recent advances ground motion evaluation pp 43 102 was utilized to model the seismic hazard for turkey using the probabilistic approach for the modeling the earthquake location uncertainty concept was employed a grid of 5106 points with 0 2 intervals was constituted for the area encompassed by the 25 46 e longitudes and 35 43 n latitudes for the return periods of 100 and 475 years the peak horizontal ground acceleration pga in bedrock was computed for each grid point isoacceleration maps for the return periods of 100 and 475 years were constructed by contouring the pga values at each node

kinematic consistency between the dead sea fault zone and the neogene and quaternary left lateral faulting in se turkey a revised quantitative kinematic model has been determined for the dead sea fault zone dsfz and the left lateral fault zones in se turkey the relative motions of the african and arabian plates across the dsfz are represented by relative rotation about 31 1 n 26 7 e at 0 40 0 02 ma 1 the northern dsfz in syria and southern turkey is interpreted for the first time as a series of transpressional stepovers along which the left lateral slip rate is substantially less than the rate of relative plate motion because this slip is oblique to the plate motion the slip rate on the east anatolian fault zone eafz is estimated as 8 mm a 1 restoring its observed slip thus requires its age to be 4 ma the previous phase of deformation which involved slip on the malatya ovacik fault zone mofz before the eafz came into being is thus dated to 7 4 ma suggesting initiation of the north anatolian fault zone nafz at 7 ma not 5 ma as previously thought the total left lateral slip on the northern dsfz in southernmost turkey is estimated as at least 65 km partitioned with 45 km on the amanos fault 10 km on the east hatay fault and a further 10 km on the kirkpinar fault farther east much of this slip is inferred to have occurred during the miocene before the modern geometry of this plate boundary zone developed when it first formed the af ar plate boundary was relatively complex it initially reactivated preexisting structures in the palmyra foldbelt in syria and in the gaziantep region of southern turkey which were significantly misaligned relative to the plate motion requiring major components of shortening as well as left lateral slip the transition from this initial rather diffuse geometry to the present localised geometry of the dsfz across western syria occurred within the miocene the predicted rate of relative motion between the stable interiors of the turkish and african plates in the vicinity of their common boundary onshore of iskenderun gulf in southern turkey is estimated as westward at 9 mm a 1 however this promontory of the african plate is itself moving westward relative to the stable interior of this plate at 7 8 mm a 1 the rate of localised left lateral slip on the onshore part of this boundary the ne trending yakapinar goksun fault is thus estimated as only 2 mm a 1 this locality can also be regarded as within the distributed boundary zone between the turkish and arabian plates the estimated relative motion between these plates is at 8 7 mm a 1 towards the ssw partitioned between localised left lateral slip at 2 mm a 1 on the yakapinar goksun fault and at least 1 mm a 1 on the amanos fault and 2 5 mm a 1 on east hatay fault with at most distributed left lateral simple shear at 3 2 mm a 1 across the amanos mountains in between however the combined slip on left lateral faults east of the amanos mountains may be as high as 6 mm a 1 with slip at 1 7 mm a 1 on the amanos fault and at 4 3 mm a 1 on the east hatay fault and any active faults farther east this requires no more than 0 7 mm a 1 of distributed simple shear across the amanos mountains raising the possibility that this component of deformation may in fact be zero this small nonzero estimate possibly indicating a closure error arising from minor errors in predicted values of other relative motion vectors it is proposed that this boundary between the turkish and african plates first developed at the same time as the mofz and nafz but its original geometry involving left lateral slip on the karatas osmaniye fault has since become locked by the presence of relatively strong ophiolitic crust within this fault zone this quantitative kinematic model demonstrates for the first time how it is possible for the left lateral faulting accommodating the nnw sse relative motion between the arabian and african plates in nw syria to dovetail into the left lateral faulting accommodating the wsw ene relative motion between the turkish and arabian plates in se turkey

the eurasian arabian and african continental margin from iran to greece the continental margin between eurasia and arabia can be traced as a continuous thrust zone for c 2000 km from the gulf of iran westwards through iran and turkey towards the mediterranean sea in this sector it forms a coherent geological whole with increasing structural complexity from s to n across the junction this clarity is terminated 125 km ne of the gulf of iskenderun on the mediterranean sea by the n s trending levant fault system lfs w of the lfs for 1400km to the w of greece the boundary significantly changes to curved micro plates which are not directly observable as they are beneath the sea their location is in doubt for c 650 km from the lfs westwards to the eastern margin of the aegean plate at the anaximander mountains over this sector several major tectonic units occur which obscure and complicate such a margin to the w the aegean plate continues for 750 km with the characteristics of an island arc

seismotectonics of the southern boundary of anatolia eastern mediterranean region subduction collision and arc jumping the pattern of seismicity and fault plane solutions of earthquakes are used to outline the tectonic features of the southern boundary of anatolia in the eastern mediterranean and southeastern turkey the results of this study show that this boundary is composed of two distinct parts one in southeastern turkey and syria is a wide and complex zone of continental collision the other in the levantine basin of the eastern mediterranean is a zone of oceanic subduction in the region of continental collision three zones of seismicity are observed most of the seismic activity in this region follows the bitlis zone and is associated with a zone of thrusting and mountain building this appears to be the zone of most active deformation and plate consumption in the plate boundary region between arabia and turkey a less active zone of seismicity to the north of the bitlis zone is interpreted to have been more active in the past whereas another active zone of seismicity to the south is interpreted to be a zone which may be more active in the future as the main zone of plate consumption jumps to the south in the subduction zone of the eastern mediterranean the depth of the subducted slab and the rate of seismicity generally increase from east to west the zone of present day convergence between africa and turkey in the levantine basin can be best outlined by the northern edge of the mediterranean ridge the subduction zone in this area sequentially jumps to the south as small continental fragments collide with existing zones of subduction deep seismic activity near the gulf of antalya is associated with a detached subducted slab north of the anaximander mountains that is distinctly different from the seismic trend which is associated with present day active subduction the plate boundary between africa and turkey at the center of the levantine basin appears to have shifted to the south of the anaximander mountains and florence rise most of the focal mechanisms of the earthquakes along the entire southern boundary of anatolia indicate that n to nnw thrusting is the dominant mode of seismic deformation the present set of data is inconsistent with a major transform fault in the cyprean arc east of cyprus and in southeastern turkey

anatolian surface wave evaluated at geofon station isp isparta turkey abstract we have studied seismic surface waves of 255 shallow regional earthquakes recently recorded at geofon station isp isparta turkey and have selected these 52 recordings with high signal to noise ratio for further analysis an attempt was made by the simultaneous use of the rayleigh and love surface wave data to interpret the planar crust and uppermost mantle velocity structure beneath the anatolian plate using a differential least square inversion technique the shear wave velocities near the surface show a gradational change from approximately 2 2 to 3 6 km s 1 in the depth range 0 10 km the mid crustal depth range indicating a weakly developed low velocity zone has shear wave velocities around 3 55 km s 1 the moho discontinuity characterizing the crust mantle velocity transition appears somewhat gradual between the depth range 25 45 km the surface waves approaching from the northern anatolia are estimated to travel a crustal thickness of 33 km whilst those from the southwestern anatolia and part of east mediterranean sea indicate a thicker crust at 37 km the eastern anatolia events traveled even thicker crust at 41 km a low sub moho velocity is estimated at 4 27 km s 1 although consistent with other similar studies in the region the current velocities are considerably slower than indicated by the preliminary reference earth model prem in almost all depth ranges

the late oligocene cevizlidere cu au mo deposit tunceli province eastern turkey the cevizlidere deposit located in the tunceli province of eastern anatolia is the largest porphyry cu au mo system in turkey the deposit is spatially related to a composite stock which was emplaced into paleozoic limestones and paleogene andesitic rocks to the southeast of the munzur mountains near the southwestern margin of the ovacik pull apart basin the host plutonic rocks at cevizlidere are porphyritic medium k calc alkaline diorites and granodiorites 40ar 39ar incremental step heating analysis of two igneous biotite separates obtained from syn mineral diorite porphyry yielded late oligocene cooling ages of 25 49 0 10 and 25 10 0 14 ma whereas hydrothermal biotite yielded an age of 24 73 0 08 ma re os ages obtained from two molybdenite separates 24 90 0 10 and 24 78 0 10 ma indicate that porphyry style alteration and mineralization developed shortly after magma emplacement the whole rock geochemical composition of the cevizlidere porphyry intrusions is consistent with derivation from partial melting of the metasomatized supra subduction zone mantle however based on regional tectonic reconstructions oligocene magmatic activity in this area appears to be related to a major kinematic reorganization that took place at around 25 ma during the switch from subduction to collisional tectonics in eastern anatolia this kinematic switch may be attributed to break off of the southern neo tethys oceanic slab prior to the arabia eurasia continent continent collision 12 10 ma following widespread middle eocene 50 43 ma arc back arc magmatism in this respect the subduction related tectonic setting of the late oligocene cevizlidere porphyry deposit is similar to that of the middle eocene copler epithermal au deposit the late timing of cevizlidere with respect to the southern neo tethys subduction may be comparable to some early to late miocene porphyry epithermal systems that lie within the contiguous urumieh dokhtar belt in central iran the later timing in iran reflects the diachronous nature of the eurasia afro arabia collision

late palaeogene neogene evolution of the triple junction region near maras south central turkey the marao region of turkey includes the anatolian arabian african triple junction the african arabian margin is marked by left lateral transtension along the dead sea kara su rift motion on the anatolian arabian boundary is partitioned between the left lateral east anatolian fault and a fold thrust belt termed the engizek zone equivalent to the bitlis suture further east the african anatolian boundary lies along the cyprus misis andirin trend and is expressed near the triple junction as the aslantao iskenderun zone now undergoing slow left lateral transtension the neogene evolution of these boundaries is largely recorded in the stratigraphy and structure of the basins that lie along the anatolian arabian lice basin and anatolian african aslantao iskenderun basin boundaries these basins appear to have developed in the early miocene along major strike slip zones large half graben in the pre neogene 9basement9 of the western misis andirin block developed contemporaneously with motion on the anatolian african boundary these extensional features evolved subsequent to the intense shattering of the mesozoic carbonate sequence in the misis andirin block and its mixing with panels of deep water palaeogene strata to form an extensionally disrupted assemblage transpression and conversion of both anatolian african and anatolian arabian boundaries to fold thrust belts occurred in the late miocene transpression continues along the anatolian arabian boundary but transtension has recurred along the anatolian african boundary since the pliocene

overview of the late tertiary recent tectonic and palaeo environmental development of the mediterranean region the late tertiary history of the mediterranean region exemplifies processes of ocean basin closure and continental collision as determined from integrated land and marine evidence during the mesozoic early tertiary tectonic settings were dominated by evolution of neotethys this ocean generally widened eastwards with a number of oceanic strands in the eastern mediterranean area great diversity of tectonic settings and palaeo environments developed during the tertiary closure history of these oceanic basins in the eastern mediterranean region more northerly neotethyan strands were closed by the mid tertiary while oceanic crust remained in the south in the present eastern mediterranean sea area northwards subduction of the remaining southerly neotethyan strand was probably active by the early miocene different areas exhibit different stages of convergence and ocean basin closure in the east the amalgamated eurasian plate had collided with the arabian margin africa by the late miocene while oceanic crust still persisted further west steady state subduction during the late tertiary gave rise to the mediterranean ridge as a substantial mud dominated accretionary wedge in the aegean area sufficient northward subduction took place to activate arc volcanism and pervasive back arc extension short of marginal basin opening in the easternmost mediterranean only limited subduction took place associated with supra subduction zone extension e g in cyprus today steady state subduction continues only locally where vestiges of neotethys remain e g herodotus abyssal plain in the western mediterranean area suturing of the african and eurasian plates initially took place in the betic region early mid tertiary where the neotethys had existed only as a narrow connection with the central north atlantic in the central mediterranean region where the western neotethys was wider northward subduction was active apparently as early as the late cretaceous in a widely accepted interpretation an andean type magmatic arc developed along the southern margin of europe and was then rifted off in the late oligocene early miocene to form the corsica sardinia block opening the north balearic marginal basin in its wake the migrating subduction zone and microcontinent then collided diachronously with north africa related continental units north africa and apulia from late oligocene early miocene giving rise to collisional thrust belts in the northern and southern apennines and along the north african continental margin i e the maghrebian chain to the betic rif area from the early miocene onwards a separate subduction system became active related to removal of neotethyan oceanic crust to the southeast ionian sea fueling suprasubduction zone extension and opening of the tyrrhenian sea orogenic collapse is an alternative mechanism of such extension and is widely believed to have caused divergent thrusting in the betic and rif regions of the westernmost mediterranean at the same time as crustal extension and subsidence of the alboran sea

constraining crustal and uppermost mantle structure beneath station tbz trabzon turkey by receiver function and dispersion analyses summary we jointly invert teleseismic radial component receiver functions and regional rayleigh and love surface wave group velocities for 1 d shear wave velocity structure beneath station tbz located on the northern side of the eastern pontides an influence factor is employed to control the relative influence of receiver function and surface wave dispersion on the resultant velocity depth profile radial and transverse component receiver functions at station tbz exhibit an azimuthal amplitude and polarity pattern consistent with 2 d receiver structure that has a general dip direction towards approximately south the radial component receiver functions are least affected by the dipping structures along the strike direction and thereby we prefer teleseismic events sampling along strike structures to alleviate the deflecting effect of dipping interfaces on the 1 d solution the 1 d inversion effectively reveals the two layer nature of the crust which is perturbed by high and low velocity layers and serves as a provisional model for the 2 d forward modelling minor to moderate changes to the 1 d model such as changing depth to and velocity contrast across an interface are needed to achieve the results with the 2 d modelling dipping interfaces and seismic anisotropy are included in the 2 d modelling to fit both radial and transverse component receiver functions the upper crust is characterized by a shear velocity of 3 5 km s 1 and cut through by a 4 km thick high velocity i e 3 8 km s 1 layer overlying the upper crust the sedimentary cover i e the top 5 km has velocities within the range 2 0 3 5 km s 1 a mid crustal velocity discontinuity between the upper granitic crust and the lower basaltic crust is identified at 16 km depth this boundary is analogous to the mid crustal discontinuity found under the black sea basin across which the shear velocity jumps from 3 5 to 4 1 km s 1 a relatively thick i e 12 km low velocity layer in the lower crust with a velocity reversal from 4 1 to 3 7 km s 1 is needed to better explain reverberations off this depth range we infer a 2 d moho discontinuity placed at 35 km depth beneath the station the proposed dip angle for the moho is rather steep i e 25 although coincident with regional gravity studies the associated sn velocity i e 4 4 km s 1 is rather low indicating disturbed upper mantle structure beneath the region initial amplitudes of transverse component receiver functions are rather energetic for which we propose substantial p and s velocity anisotropy 12 per cent for the topmost depths 5 km

evidence from the gediz graben for episodic two stage extension in western turkey western turkey falls within a wide belt of nne ssw directed active continental extension generally similar to the basin and range province of the usa it comprises a zone of wnw ese trending major grabens detailed study of the gediz graben reveals two contrasting infills that represent two distinct extensional stages separated by a short phase of compression the older infill consists of an 800 m thick folded and exhumed continental sedimentary sequence with intercalated calc alkaline volcanics it accumulated in a basin formed in the northern hanging wall of a detachment fault during miocene early pliocene times the younger infill rests on the older infill with angular unconformity and consists of about 170 m of undeformed terraced continental sediments and basaltic lavas it accumulated during plio quaternary times in an asymmetric graben bounded by step like normal faults this later extension was probably triggered by the commencement of sea floor spreading along the red sea in early pliocene times and has persisted to the present almost all the grabens in western turkey are best explained by this episodic two stage graben model with an intervening phase of short term compression which differs from the progressive evolution inferred for the basin and range province of the usa

structure and kinematics of the central sivas basin turkey salt deposition and tectonics in an evolving fold and thrust belt this work has been made possible by funding from total s a in the framework of the structural geology chair at e2s university of pau pays adour held by jean paul callot

age and tectonomagmatic setting of the eocene copler kabatas magmatic complex and porphyry epithermal au deposit east central anatolia turkey the copler epithermal au deposit and related subeconomic porphyry cu au deposit is hosted by the middle eocene copler kabatas magmatic complex in central eastern anatolia the intrusive rocks of the complex were emplaced into late paleozoic mesozoic metamorphosed sedimentary basement rocks near the northeastern margin of the tauride anatolide block igneous biotite from two samples of the magmatic complex yielded 40ar 39ar plateau ages of 43 75 0 26 ma and 44 19 0 23 whereas igneous hornblende from a third sample yielded a plateau age of 44 13 0 38 these ages closely overlap with 40ar 39ar ages of hydrothermal sericite 44 44 0 28 ma and biotite 43 84 0 26 ma and re os ages from two molybdenite samples 44 6 0 2 and 43 9 0 2 ma suggesting a short lived 1 my magmatic and hydrothermal history at copler no suitable minerals were found that could be used to date the epithermal system but it is inferred to be close in age to the precursor porphyry system the copler kabatas intrusive rocks show i type calc alkaline affinities their normalized trace element patterns show enrichments in large ion lithophile and light rare earth elements and relative depletions in middle and heavy rare earth elements resembling magmas generated in convergent margins however given its distance from the coeval eocene maden helete volcanic arc the complex is interpreted to be formed in a back arc setting in response to paleocene slab roll back and upper plate extension the tectonomagmatic environment of porphyry epithermal mineralization at copler is comparable to some other isolated back arc porphyry systems such as bajo de la alumbrera argentina or bingham canyon usa

source characteristics and b values of the tuz golu fault zone in central anatolia turkey abstract we investigate significant earthquake sequences in the observation period between 2000 and 2018 along the tuz golu fault zone in central anatolia these sequences include a series of strong events with moment magnitudes mw 5 0 e g 30 july 2005 bala ankara mw 5 2 20 december 2007 bala ankara mw 5 7 and 26 december 2007 mw 5 6 afsar ankara earthquakes the mainshocks are shallow focus strike slip events with minor normal component at depths of 12 15 km focal depths of aftershocks range from 2 to 30 km the focal mechanisms of the aftershocks are mainly normal faulting with variable strike slip components the geometry of focal mechanisms reveals a normal faulting regime with e w and also ne sw trending directions of t axis in the entire activated region a stress tensor inversion of focal mechanism data is performed to acquire a more accurate picture of the tuz golu fault zone stress field the stress tensor inversion results display a predominant normal stress regime with a nne ssw oriented maximum horizontal compressive stress sh according to high resolution hypocenter relocations of the tuz golu fault zone seismic sequences eight clusters are revealed the aftershock activities in the observation period between 5 march 2000 and 2 june 2018 extend from nw to se direction seismic cross sections show that a complex pattern of the hypocenter distribution with the activation of tuz golu fault zone segments the western clusters are associated with a fault plane trending mainly n s and dipping towards almost vertical while the eastern clusters are related to a fault plane trending nw and dipping towards se direction the best constrained focal depths are mainly confined in the crust depth

differential neotectonic rotations in anatolia and the tauride arc palaeomagnetic investigation of the erenlerdaǧ volcanic complex and isparta volcanic district south central turkey abstract in the anatolian sector of the alpine himalayan collisional belt a palaeotectonic phase of terrane accretion has been succeeded by a neotectonic phase of intracontinental deformation as the afro arabian plate has continued to impinge differentially into the accreted collage the resulting tectonic escape has during the last few million years extruded and rotated blocks in a southwesterly direction this paper reports a palaeomagnetic investigation of the erenlerda volcanic complex and isparta alkaline volcanic district undertaken to extend analysis of crustal rotation into the southwestern part of the anatolian region and investigate the interaction with the isparta angle and the extensional province of western turkey the erenlerda volcanism comprises three phases of volcanism the oldest sille volcanics 11 7 11 4 ma yield a mean d 150 i 52 rotated anticlockwise during early stages of crustal thickening and deformation before a later miocene episode c 10 9 8 9 ma d 183 i 47 and a mio pliocene episode d 179 i 51 the latter two episodes indicate that no significant rotation has resulted during the neotectonic crustal extrusion in this southwestern sector of anatolia further to the west within the isparta angle a 4 7 4 0 ma alkaline episode yields a mean of d 186 i 53 rotated slightly clockwise the pattern of palaeomagnetic declinations across anatolia shows rotations that are strongly anticlockwise in the east near the arabian pincer and diminish towards the west to become zero or slightly clockwise at the western extremity of the collage the timing of rotation also appears to become younger towards the south crustal deformation has therefore been distributed and the net effect of terrane extrusion to the west and south has been to expand the curvature of the tauride arc and by inference the cyprian arc where good age control exists in cappadocia and the sivas basin rotations are found to be concentrated within the last few million years and are up to an order higher than rates deduced from global positioning system the palaeomagnetic data imply that the neotectonic deformation following collision initially produced crustal thickening resulting in uplift of the anatolian plateau and was only subsequently accommodated by major differential block rotation during tectonic escape

comment on a new intracontinental transcurrent structure the central anatolian fault zone turkey by a kocyigit and a beyhan abstract kocyigit and beyhan have described the central anatolian fault zone cafz as a 700 km long active strike slip fault zone in turkey if their interpretation is correct then several major turkish cities are vulnerable to a significant earthquake hazard which was previously unsuspected and the existing close agreement between observed slip rates on major strike slip faults in turkey and predictions from global plate motion models is spurious whether the cafz is real or based on mistaken interpretations of diverse evidence is thus a matter of some importance the aim of this comment is to describe difficulties which arise over the published interpretation of the cafz with the aim of encouraging either a retraction or a more thorough presentation of the available evidence in support of the existence of a major active fault zone in the required position three main difficulties are discussed in detail first strands of the cafz have been interpreted in many localities where previous detailed studies have either found no evidence of faulting or have reported ancient faults which have been described as no longer active second many other features which previous studies have explained satisfactorily are reinterpreted as consequences of active strike slip faulting finally no observational evidence is presented for the slip rate or the timing of the start of the alleged present phase of slip on the cafz the suggestion that it has slipped by 24 km during this present phase of activity is inadequately documented and conflicts with other evidence

basalt magma genesis and fractionation in collision and extension related provinces a comparison between eastern central and western anatolia experimental studies of synthetic and natural basalt systems suggest that conditions of magma genesis and fractionation depend fundamentally on mantle temperatures and lithospheric stress fields in general compressional settings are more conducive to polybaric fractionation than extensional settings and in this regard the anatolian magmatic province offers a natural laboratory for comparing near coeval basalt eruptions as a function of regional tectonics compressional collision related regimes dominating in eastern anatolia and extensional tectonics characterizing a western province related to aegean sea opening projection of plio quaternary basalt normative compositions from the western anatolia extensional province waep the central anatolian ova province caop and eastern anatolia compressional province eacp are projected onto ol ne cpx and pl cpx ol planes in the simplified basalt system ne cpx ol qz each showing distinctive liquid lines of descent waep basalts are mostly constrained by low pressure 0 5 gpa cotectics while caop and eacp compositions conform to moderate and or high pressure 0 8 3 0 gpa cotectics overall a quasi linear shift from moderate and or high pressure to low pressure equilibria matches the westward transgression from compressional east anatolia to the extensional west anatolian aegean region comparison of their respective primary mantle equilibrated magmas simulated by normalizing their compositions to mgo 15 wt mg 15 with parameterized anhydrous and h2o undersaturated experimental melts suggests they segregated from spinel to garnet lherzolite mantle facies at pressures between c 2 and 3 gpa c 70 100 km depth under h2o undersaturated conditions interpolated potential temperatures tp and lithospheric stretching factors range as follows 1 eastern anatolian basalts associated with the arabian foreland show tp varying between 1250 and 1400 c except for the karacalidag alkali basalts south of the bitlis zagros fracture zone for which tp ranges up to 1450 c for values of 1 2 1 8 tp values for central anatolia e g sivas range between 1300 and 1375 c except for karapinar egrikuyu and hasandag which show 1150 c and values of 1 3 1 4 for western anatolian basalts tp range mostly between 1250 and 1330 c except for a single value for canakkale of 1400 c and kula sample showing tp 1200 c and values of 1 3 2 0 variation of these conditions is as great or greater than that between provinces although there are clearly significant constraints on the inferred polybaric to low pressure isobaric fractionation regimes covariation of total feo tio2 la yb ce sm zr y and zr nb reflects small but significant differences in bulk composition and ambient melt fraction while the covariance of ce sm and sm yb is consistent with the segregation of primitive melts at the spinel to garnet lherzolite transition

high pressure metasediments in central turkey constraints on the neotethyan closure history 1 the distribution of oceanic domains and continental blocks in central anatolia remains a challenge in understanding the alpine geodynamic evolution of the tethys realm the consumption of a neotethys oceanic branch at the mesozoic cenozoic boundary welded the central anatolian crystalline complex in central turkey and the anatolide tauride block in western turkey with the northerly eurasian margin whether those two regions constituted a single or two distinct continental masses is still matter of debate high pressure metamorphism has been locally evidenced in the afyon zone which was however defined as a greenschist facies metamorphic zone of the anatolide tauride block since the afyon zone composes a metamorphic equivalent of a continental margin exposed far south of the izmir ankara suture zone this encouraged us to reevaluate its metamorphic evolution in order to better understand the relation between western and central turkey our investigations reveal that the high pressure minerals fe mg carpholite and glaucophane are present in the entire afyon zone which we reconsider as a blueschist facies zone we additionally present a tectonic reconstruction stripping off the postcollisional tectonics it reveals that today s bending of the high pressure belt is consistent with an eocene collision of the anatolide tauride block around the southern edge of the central anatolian crystalline complex we argue that the central anatolian crystalline complex and the anatolide tauride block were two distinct continental masses separated by a neotethyan oceanic stripe the closure of which engendered subduction related metamorphism in the latter and arc volcanism and high grade metamorphism in the former by late cretaceous to early cenozoic

palaeomagnetic study of the erciyes sector of the ecemis fault zone neotectonic deformation in the southeastern part of the anatolian block

spatial variability of surficial shallow water sediment geoacoustic properties in a previous publication richardson in ocean seismo acoustics plenum new york 1985 pp 527 536 the author reviewed relationships between physical and biological processes and the resultant variability of values of sediment geoacoustic compressional wave velocity and attenuation and physical grain size and porosity properties in this presentation the subject is revisited using values of compressional and shear wave velocity measured in situ instead of the laboratory measurements considered in the previous paper

effects of plate convergence obliquity on timing and mechanisms of exhumation of a mid crustal terrain the central anatolian crystalline complex abstract apatite fission track ft ages from the central anatolian crystalline complex cacc a microcontinent within the turkish segment of the alpine himalayan orogen vary dramatically from north to south this variation correlates with differences in the obliquity of convergence of the continental fragment relative to the pontide belt for the northern cacc and the tauride belt for the southern cacc the northern cacc was deformed and metamorphosed during late cretaceous orogen normal collision and was exhumed from the mid crust to shallow crustal levels 50 ma to the present in contrast the southern cacc nigde massif was initially deformed and metamorphosed during late cretaceous contraction but subsequently developed as a metamorphic core complex in a wrench dominated regime and was exhumed to

linking slab break off hellenic trench retreat and uplift of the central and eastern anatolian plateaus abstract the central and eastern anatolian plateaus are integral parts of the world s third largest orogenic plateau in the past decade geophysical surveys have provided insights into the crust lithosphere and mantle beneath eastern anatolia these observations are now accompanied by recent surveys in central anatolia and new data constraining the timing and magnitude of uplift along its northern and southern margins together with predictions from geodynamic models on the effects of various processes on surface deformation and uplift the observations can be integrated to identify probable mechanisms of anatolian plateau growth a changeover from shortening to extension along the southern margin of central anatolia that is coeval with the start of uplift can be most easily associated with oceanic slab break off and tearing this interpretation is supported by tomography deep seismicity or lack thereof and gravity data based on the timing of uplift geophysical and geochemical observations and model predictions slab break off likely occurred first beneath eastern anatolia in middle to late miocene time and propagated westward toward cyprus by the latest miocene alternatively the break off near cyprus could have occurred in late pliocene to early pleistocene time in association with collision of the eratosthenes seamount continental fragment with the subduction zone uplift at the northern margin of central anatolia appears to result from crustal shortening starting in the late miocene or early pliocene which has been linked to the broad restraining bend of the north anatolian fault the uplift history of the interior of central anatolia since the late miocene is unclear although shortening there appears to have ended by the late miocene followed by ne sw extension this change in the deformation style broadly coincides with faster retreat of the hellenic trench as well as uplift of the northern and southern margins of central anatolia these different events throughout the plateau may be linked as faster retreat of the hellenic trench has been predicted to occur after slab break off which could have induced extension of central anatolia and helped to form the north anatolian fault through accelerated westward movement of anatolia relative to eurasia correlative geochronologic evidence that we summarize here supports the hypothesis that the geodynamic activity throughout the aegean anatolian domain starting in latest miocene to early pliocene time defines a series of events that may all be linked to slab break off

constraints on arabian plate motion and extensional history of the red sea analysis of the geologic and geophysical data from the western and northern margin of the arabian plate combined with data from the red sea gulf of aden leads to an interpretation of arabian plate motion that supports an episodic extensional history in the red sea and gulf of aden phase 1 extension began in medial to late eocene and was caused by the nw propagation of the reoriented central indian ridge spreading center it stretched and thinned continental crust along numerous wrench and normal faults that reactivated preexisting structures first phase extension stopped when the arabian plate terminally sutured to eurasia in the medial miocene and halted northward movement of arabia relative to africa the combined african arabian plates moved north more slowly constricting and thickening continental crust in the bitlis zagros sutures while the red sea remained technically quiescent and accumulated salt by the early pliocene continued northward movement was accommodated by lateral extrusion of large continental wedges north of the bitlis zagros sutures this allowed arabia to move northward faster than africa and reopen the red sea where phase 2 extension was expressed by seafloor spreading extension within the red sea gulf of aden rift system has been controlled by the interactions and effects of two factors 1 convergent processes between the north margin of the arabian plate and the eurasian plate to the north and 2 northwest propagation of extension associated with the medial eocene reorganization of the central indian spreading center

block rotation in western turkey 1 observational evidence western turkey is a region of rapid continental extension where extension rate increasing westward causes counterclockwise vertical vorticity and hence counterclockwise rotation around vertical axes on a regional scale field observations and seismicity of the past century are used to deduce positions and slip senses of major active oblique normal faults in this region which take up extension in the upper crustal brittle layer and allow fault bounded blocks to rotate around vertical axes the principal active normal faults in western turkey strike roughly east west near the aegean coast turning gradually toward westnorthwest eastsoutheast strike across 200 km distance inland to the east slip vector azimuths indicate typical extension direction on these faults is s18 8w they truncate a second set of faults with smaller displacement and roughly orthogonal strike and slip vector azimuth as well as subdividing the brittle layer into blocks that show little internal deformation some major oblique normal faults subdivide it into domains that show different neogene rotation around vertical axes some domains contain sets of major active oblique normal faults that bound blocks that are elongated angular and shaped like tilted dominoes these faults take up extension and can also take up rotation around vertical axes provided they and the blocks between them rotate around vertical axes at the same rate where adequate paleomagnetic observations are available they indicate these domains have rotated counterclockwise as expected by up to 40 roughly equal to the change in strike of the principal set of active faults between the aegean coast and the eastern edge of the actively extending zone however evidence is scarce for the right lateral strike slip expected in some kinematic models on a set of oblique normal faults that takes up extension and counterclockwise rotation instead each fault appears to have the component of strike slip necessary to enable it given its local strike to slip in ue direction in which the region is extending two domains that have rotated clockwise are approximately circular in plan view with diameter 90 km and are bounded by faults with variable orientation each comprises a single block with no internal major active faults

palaeoenvironmental analysis of a miocene basin in the high taurus mountains southern turkey and its palaeogeographical and structural significance determination of the relationships between the southern marine dominated miocene basins of south central turkey and their continental hinterland in southern turkey has traditionally been frustrated by the apparent absence of basin remnants within the taurus mountains the dikme basin which seems to be an enclave of basin remnants within the aladag mountains eastern taurides consists mainly of coarse grained continental sediments of various facies these mostly early middle miocene sediments were studied to determine the depositional environments and the factors controlling the basin formation and basin fill architecture to attempt to close the information gap between the adana basin to the south and central anatolian miocene further to the north a generally southwest flowing axial fluvial system and interfingering coarse grained marginal alluvial clastics derived from northwest and southeast were identified the marginal facies to the northwest is bounded by a n 55 e running structural lineament that starts from the ecemis fault zone and in digital elevation models extends toward the north of the study area along this lineament miocene sediments onlap steep fault line escarpments certain miocene levels are tectonically disrupted and an intraformational unconformity and boulder conglomerates are also well developed in the miocene sequence the southeast boundary is similarly defined by a ne trending fault that periodically elevated the adjacent tufanbeyli autochthon producing coarse clastics from this area this boundary fault also induced fining upwards vertical patterns and synsedimentary deformation in the marginal facies additionally the central part of the basin exhibits a distinct fault defined morphology characterized by small scale tens of metres to 150 m high valley and sill topography a thin marine interval was also encountered in the southernmost part of the basin indicating that the clastic system originating around this area debouched into a miocene sea situated further to the south the proposed palaeogeography and basin fill model suggests that the dikme basin and similar miocene remnants all controlled mainly by a northeast running extensional or transtensional fault system may have been parts of the terrestrial hinterland that supplied sediment to rapidly subsiding marine areas further south such as the adana basin

variability in geoacoustic and related properties of surface sediments from the venezuela basin caribbean sea abstract the spatial variability of sediment geoacoustic and related properties was determined from replicate 0 25 m 2 usnel box core samples collected from three sedimentary provinces in the venezuela basin the maximum variation in sediment physical chemical and geoacoustic properties occurred among distant sites representing pelagic turbidite or hemipelagic sedimentary regimes rather than within sites or within core depth gradients variability among sites was a function of differences in calcium carbonate dissolution among a water depth gradient of 1550 m 3500 5050 m and differences in the relative contribution of particles from pelagic and terrigenous sources the least amount of variation was evident among subcores obtained from the same box core or site suggesting that a single subcore was adequate to describe sediment physical and geoacoustic properties over large areas of the sea floor the considerable amount of downcore variability in sediment properties was a function of gradients in biological activity biologically mediated chemical changes and the presence of ponded terrigenous sediments deposited by intermittent turbidite flows interspersed between sediments of pelagic origin for sediments with greater than 35 calcium carbonate porosity is a good predictor of compressional wave velocity whereas mean grain size is a good predictor of compressional wave attenuation porosity mean grain size relationships had little predictive value in carbonate sediments the differences among these and previously published empirical relationships show that particle size distribution of larger carbonate material and composition of the sediment matrix must be considered when predicting sediment geoacoustic properties sediment shear strength did not show any correlation with other sediment physical or acoustic properties and is primarily controlled by biological and chemical processes

fault block rotations at the edge of a zone of continental extension southwest turkey the ne sw trending burdur acigol and baklan basins of southwest turkey are bounded by normal faults which became active in quaternary times prior to this a more widely spaced system of pliocene basins had existed each of the quaternary basins has a half graben geometry with a major nw dipping fault on its southeast side previous studies of the 1971 burdur earthquake caused by movement on the fault bounding the burdur basin have shown this fault to flatten slightly at depth deformation in the hangingwall of the fault controlling the pliocene basin in the burdur region suggests a planar fault geometry it is suggested that the pliocene fault rotated to its present shallow orientation then became inactive and acted as a detachment at depth for the more recent quaternary fault quaternary faults bounding the burdur acigol and baklan basins have a sinistral strike slip component with slip vectors indicating extension in an nw se direction this is at variance with regional n s extension in western turkey a solution for this contrast is found by invoking block rotations about vertical axes in a deforming zone between the rapidly extending aegean region to the west and the stable unstretched anatolian plateau to the east

neotectonics and long term seismicity in europe and the mediterranean region we present a neotectonic model of ongoing lithosphere deformation and a corresponding estimate of long term shallow seismicity across the africa eurasia plate boundary including the eastern atlantic mediterranean region and continental europe gps and stress data are absent or inadequate for the part of the study area covered by water thus we opt for a dynamic model based on the stress equilibrium equation this approach allows us to estimate the long term behavior of the lithosphere given certain assumptions about its structure and physics for both land and sea areas we first update the existing plate model by adding five quasirigid plates the ionian sea adria northern greece central greece and marmara to constrain the deformation pattern of the study area we use the most recent data sets to estimate the lithospheric structure the models are evaluated in comparison with updated data sets of geodetic velocities and the most compressive horizontal principal stress azimuths we find that the side and basal strengths drive the present day motion of the adria and aegean sea plates whereas lithostatic pressure plays a key role in driving anatolia these findings provide new insights into the neotectonics of the greater mediterranean region finally the preferred model is used to estimate long term shallow seismicity which we retrospectively test against historical seismicity as an alternative to reliance on incomplete geologic data or historical seismic catalogs these neotectonic models help to forecast long term seismicity although requiring additional tuning before seismicity rates are used for seismic hazard purposes

non marine sedimentation associated with oligocene recent exhumation and uplift of the central taurus mountains s turkey abstract three related basins in southern turkey the ecemis basin the karsanti basin and the aktoprak basin document the neogene recent regional exhumation and surface uplift history of the central taurus mountains the regional tectonic framework was established by a late eocene phase of compressional deformation that ended tethys related marine deposition during the oligocene early miocene non marine sedimentation was dominantly from braided rivers flowing from the nascent taurus mountains and from the nigde metamorphic massif further north during this period erosion more or less kept pace with exhumation and the topography remained subdued allowing a marine incursion probably eustatically controlled into the karsanti basin in the east during early oligocene time regional exhumation was possibly controlled by thermal uplift of an actively extending area located behind the subducting s neotethys in the eastern mediterranean sea during exhumation largely ophiolitic rocks were eroded revealing the deformed mesozoic tauride carbonate platform beneath the area was affected by a short lived pulse of compressional deformation transpression probably in mid miocene time but extensional exhumation then resumed as indicated by the presence of metamorphic derived clasts from the adjacent nigde massif late miocene deposition was dominated by large inward draining lakes consistent with regional evidence of a humid climate during this time strong surface uplift took place during plio quaternary time drainage to the mediterranean became established allowing river valleys to incise deeply into the flanks of the taurus mountains palaeo valleys were successively infilled with coarse alluvial sediments this deposition was influenced by ne sw trending extensional faults in addition the sedimentary evolution of the area was strongly influenced by the nne ssw trending ecemis fault zone which has experienced ca 60 km of left lateral strike slip since the late eocene an important pulse of normal faulting transtension in latest miocene early pliocene time generated large fault scarps these acted as sources for large plio quaternary alluvial fans which prograded across active strike slip faults the morphology of these fans was influenced by a combination of quaternary climatic change axial fluvial downcutting and active strike slip tectonics in general the plio quaternary regional uplift of the taurus mountains may relate to underplating of material derived from the african plate during progressive collision with the anatolian eurasian plate in the vicinity of the easternmost mediterranean sea

upper miocene pleistocene deformation of the girne kyrenia range and dar dere ovgos lineaments northern cyprus role in collision and tectonic escape in the easternmost mediterranean region

climate controlled river terrace formation in the kizilirmak valley cappadocia section turkey inferred from ar ar dating of quaternary basalts and terraces stratigraphy abstract this study was carried out on the cappadocia section of the kizilirmak river valley the longest river completely within the borders of turkey 1355 km a staircase of fifteen terraces found in the valley is maintained against erosion at elevations up to 160 m above the current river level the gulsehir karaburna quatenary basalts four basalt flows which cap four terraces were numerically dated for the first time using the ar ar technique the evren ridge basalt 1 160 m above the river level and capping terrace 1 was dated to 1989 4 38 9 ka the karaburna basalt plateau 2 is 128 m above the river level and caps terrace 4 and was dated to 1228 2 46 4 ka the tuzkoy basalt plateau 3 29 m above the river level and capping terrace 12 was dated to 403 8 9 8 ka and the karniyarik hill basalts 4 at 4 5 m above the river level and capping terrace 15 were dated to 96 0 13 0 ka these basalt ages provide minimum ages for the underlying fluvial deposits on the one hand these data show that kizilirmak river incised its valley by 160 m during the last 2 ma of its evolution on the other hand by using terrace sequences and basalt ages the time averaged incision rate of the river during the last 2 ma was determined as approximately 0 08 mm a 1 but important variations within that time span are also apparent the highest incision rate during this period was determined to be 0 12 mm a 1 between the late early and mid middle pleistocene from the numerical chronology terrace stratigraphy and paleosol records it is suggested that the main incision phases of the kizilirmak river led to terrace formation during the cold periods and the deposition phases occurred during the warm periods including cold warm transitions as a result of assigning terraces to marine oxygen isotope stages it was inferred that nearly all terrace levels had formed during the eccentricity driven climate cycles in association with high uplift rates which were interpreted as being complete in the valley

the kazova basin an active negative flower structure on the almus fault zone a splay fault system of the north anatolian fault zone turkey abstract the kazova basin is located within the almus fault zone afz a splay fault system of the north anatolian fault zone in the central pontides turkey it is a 0 7 10 km wide 60 km long wedge shaped right lateral strike slip depression bounded by the mercimekda i camdere fault set in the north and the tokat fault set in the south the kazova basin is superimposed on pre pliocene basement rocks while its basin fill comprises the pliocene to lower quaternary kizkayasi and cerci formations and quaternary alluvials the mercimekda i camdere and tokat fault sets of the afz the basin margin faults of the kazova basin have a considerable amount of normal separation and show a divergent character here the kazova basin is interpreted as an active negative flower structure where the combination of normal movement extension along the different segments of the afz and the oblique extension between its branching splays resulted from a natural response to the anticlockwise rotation along the afz are suggested basin forming mechanism this kind of basin is first from turkey although different types of strike slip basins such as fault wedge pull aparts composite pull aparts are widely represented and well known

mio pliocene basin development in the eastern part of the cappadocian volcanic province central anatolia turkey and its implications for regional tectonics the cappadocian volcanic province cvp comprises predominantly of a thick succession of volcanogenic rocks and interbedded siliciclastic sediments of middle miocene to recent age in central anatolia turkey the conditions of basin development in the eastern part of the cvp have been elucidated by using sedimentological and geomorphological approaches the prevailing tectonic regime its extent and causes are also discussed sedimentological analysis supported by geomorphological observations revealed a major ne trending probably normal border fault and its several synthetics this tectonic element constitutes the se margin of the basin and divided the cvp from the tauride range during middle miocene to pliocene the basin fill in the study area comprises gravelly alluvial fans near the border fault while fluvial clastics and lacustrine carbonates dominate towards the centre some pyroclastic rocks and lava flows are also made part of the fill the southeastern basin margin is characterized morphologically by a number of uplifted basement blocks probably associated with synthetic faults and some deeply incised canyons in the footwall these canyons were subsequently filled with a mid pliocene ignimbrite sheet and represent the sediment supply conduits to the basin the cessation of filling in the basin was determined by strike slip faults that uplifted and detached the basin about 2 6 ma this date also marks the onset of the neotectonic period in the region the overall extensional tectonic regime inferred for the eastern cvp appears coeval with events recognised in the southern basins i e adana and mut basins and the eastern mediterranean some physical connections between these basins also have been demonstrated it is suggested that the cvp and the southern basins were all created during a phase of extension resulting from continued northward subduction of the african plate beneath the eurasia during the late cenozoic

coeval extensional shearing and lateral underflow during late cretaceous core complex development in the nigde massif central anatolia turkey 1 the nigde massif at the southern tip of the central anatolian crystalline complex consists of two structural units foliations in the lower unit define a dome cored by migmatites the contact between the two units bears all the elements of a ductile to brittle extensional detachment hence the nigde massif represents an extensional metamorphic core complex top to ne ene shearing at higher levels of the lower unit relates to displacement along the detachment deeper levels of the lower unit display high temperature top to ssw ductile shearing the two shearing deformations show a difference in the mean trend of stretching lineations of up to 58 new 40ar 39ar ages combined with previously published data enable us to infer that the two shears were contemporaneous in our favored interpretation oblique shearing in the core of the dome reflects lateral underflow i e horizontal flowing of the lower crust in a direction highly oblique to the direction of extension as a result of the interaction between lateral underflow and downdip shearing along the overlying detachment distinct structural domains are expected to exist within the migmatitic part of the core complex with observed counterparts in the nigde dome lateral underflow may reflect inward flow on the scale of the core complex regional scale channel flow is an alternative that would better account for the record of non coaxial deformation in the core of the dome more generally we suspect that the development of lateral underflow in a metamorphic core complex more likely reflects regional channel flow rather than local inward flow

palaeomagnetism and magnetic properties of the cappadocian ignimbrite succession central turkey and neogene tectonics of the anatolian collage abstract the cappadocian ignimbrite succession of central southern anatolia comprises at least nine major and two minor calc alkaline rhyolitic sheets emplaced at 1 2 ma intervals between 11 2 and 1 1 ma it records the last phase of neotethyan subduction during final emplacement of the tauride orogen in southern turkey this study reports magnetostratigraphy and describes associated rock magnetic properties remanence resides in ti poor titanomagnetites haematisation is locally produced by post emplacement oxidation but does not contribute significantly to the palaeomagnetic signature although secondary processes within the ignimbrite sheets have produced composite isothermal remanent magnetisation spectra and variable intensities of magnetisation weak anisotropy of magnetic susceptibility describes tensors with maximum axes close to bedding and minimum axes perpendicular to this plane directions of kmax with weak imbrication mostly suggest flow away from centres of eruption located by gravity and remote sensing older ignimbrites upper and lower goreme akdag zelve from the cardak centre are all of normal polarity later ignimbrites partly erupted from the derinkuyu centre comprise the sarimaden r cemilkoy r tahar r kizilkaya r incesu n and valibaba sofular r ignimbrites the overall reversed group mean is d i 174 51 n 10 units r 9 84 95 6 6 k 55 and all magnetisation directions from the upper goreme 9 0 ma onwards are rotated anticlockwise with respect to eurasian and african palaeofields this sense of rotation characterises most of central anatolia and averages 9 5 in this sector the rotation rate from 8 to 1 ma bp was 1 25 ma but it appears to have accelerated during the latter part of the quaternary to about an order higher than rates determined from gps rotation has resulted from extrusion of fault blocks during tectonic escape of the anatolian collage to the southwest and followed crustal thickening as the afro arabia plate has continued to impinge differentially into eurasia cenozoic magnetic inclinations are systematically shallower across anatolia than inclinations expected from the geocentric dipole model and the apparent polar wander of bordering major plates only part of this difference 400 km can be accommodated by northward movement and crustal thickening in central anatolia since mid miocene times shallow inclinations observed in the aegean region extend into turkey they are observed in young volcanics and appear to reflect a regional geomagnetic anomaly the pattern of neotectonic declinations across anatolia shows rotations that are strongly anticlockwise rotated in the east near the arabian pincer but diminish towards the west to become zero or slightly clockwise at the western extremity of the collage rotations also seem to become generally younger towards the south crustal deformation has therefore been distributed and the net effect of terrane extrusion to the west and south has been to expand the curvature of the tauride arc and by inference the cyprus arc

tectonic stress state in ne japan as part of the okhotsk plate abstract an existing geodetic flow velocity model obtained by using an internal free network adjustment technique is used to derive estimates for various strain rates parameters in ne japan the greatest shortening rates of the principal strains trending e w are located in regions where much steady internal frame invariant plastic flow deformation is observed to be taking place the internal geodetic adjustment technique yielded the internal deformation in the tohoku arc most of the intraplate deformations including the much folding deformations observed in the inner zone are produced from within an interseismic transient elastic loading at a strongly coupled locked japan trench would not be needed the observed ongoing extensive ductile folding deformation in the inner zone of tohoku may mean that the geodetic strain rates causing shortening at 2 3 cm yr probably reflect the more correct level of the deformation which is steady permanent in ne japan as compared with seismic faulting data which indicate 0 5 cm yr shortening the calculated principal strain rates are used to make an interpretation for the origin of the deviatoric principal stresses within the greater regional plate tectonic framework the tectonic stress state in ne japan as part of the okhotsk plate could mostly be influenced by the okhotsk plate which is extruding southward to lessen the significant accumulated contractional deformation in ne asia in the verkhoyansk cherskii mountains the principal strain rates are n s extensional essentially everywhere in ne japan as a result of the southerly extrusion except in its southernmost leading edge in the uetsu fossa magna province where the japan alps rampart rises in front of the extrusion here an e w compressional stress state prevails a second e w contractional zone is found in north central tohoku extending from the sanriku province in the outer zone to the inner zone in the japan sea side being more prevalent in the latter zone the calculated rotation rates from the geodetic flow model are clockwise cw in both of the e w contractional regions ne japan extruding southward faces buttresses in 1 the oga ojika line ool and or a crustal weakness zone between the northern and the southern halves of tohoku approx at 38 5 n latitude and especially 2 the japanese alps rampart these obstacles cause the northern and southernmost tohoku to veer to its right and rotate cw thereby setting up the e w trending compressional deformation in their respective inner zones between the ool or the 38 5 n boundary and the kanto tectonic line ktl the sense of the differential rotations is counterclockwise ccw towards the ocean to the se the northern tohoku north of the ool and the southernmost tohoku south of the ktl cannot rotate ccw towards the ocean because of the izu block s collision in the south and the relatively strong coupling along the subduction interface beneath the japan trench in the north off sanriku the relatively stronger long term coupling between the northern tohoku and the pacific plate at the sanriku coast with respect to that in off fukushima is due to a flatter subduction of the pacific slab there increasing the plates interface contact area the flattening of the subduction dip angle was caused by ccw rotation and shifting of the northern tohoku along the dextral honjo matsushima line roughly corresponding to the ool towards the pacific and overriding of the subduction zone during the formation of the japan sea

a base flow separation algorithm based on the linearized boussinesq equation for complex hillslopes 1 the separation of base flow from discharge records is an important issue in hydrology the objective of this paper is to develop a base flow separation algorithm based on groundwater theory in which the shape of the aquifer is taken into account and for which the parameters can be estimated from river discharge measurements for this purpose an analytical solution to the linearized boussinesq equation for realistic aquifer shapes and temporally variable recharge rates is derived this solution is combined with a mass balance at the land surface in order to construct the base flow separation algorithm the parameters of the base flow filter are calculated on the basis of the same analytical solution comparison of the results of the new algorithm to existing base flow separation methods shows the need for a physical basis for base flow filters

sedimentary development of the oligocene karsanti basin southern turkey in its regional tectonic setting abstract following late cretaceous ophiolite and melange emplacement within the tauride belt several neogene sedimentary basins of variable size were formed along the southern flank of the taurus continent in southern turkey these include the pozanti and karsanti basins and the regional scale cukurova basin complex extending southwestwards into the cilicia kyrenia basin the karsanti basin is bounded by the regional scale sinistral ecemis fault zone to the west the east anatolian fault zone to the southeast and the negoene adana basin to the south deformed palaeozoic and mesozoic rock units that display an irregular palaeotopography form the basement of the karsanti basin these units are overlain by an allochthonous kizildag melange and by thrust slices of basic ultrabasic ophiolitic rocks farasa ophiolites that were emplaced in this region during the late maastrichtian the karsanti basin was formed during the oligocene above the thrust sheets the karsanti basin disconformably overlies the ophiolitic nappes and is interpreted as a n s trending half graben which was probably most active following the deposition of lacustrine sediments during the late oligocene the main karsanti basin infill is represented by four lithological units 1 alluvial fan deposits a1 2 shallow marine deposits a2 3 lacustrine deposits a3 and 4 fluvial deposits a4 these sediments were deposited during the oligocene prior to the initiation of the main adana basin which formed in a separate intermontane setting the karsanti basin fill is unconformably overlain by early miocene sediments of the neogene adana basin