seismic risk in turkey the aegean and the eastern mediterranean the occurrence of large magnitude earthquakes summary the file of turkish seismicity developed by kandilli observatory istanbul for earthquakes to 1970 is extended here up to 1978 using 1sc and pde data entries into this file are maintained on the surface wave magnitude scale m and conversion of body wave magnitude mb to m has been carried out where necessary using a formula derived for turkish earthquakes completeness analysis suggests that magnitudes m 4 5 may be used for statistical evaluation of seismic risk this file is analysed by a range of methods to provide a suite of risk forecasts forecasting results from least squares and maximum likelihood estimates of the whole process gutenberg richter cumulative frequency law of earthquake magnitude occurrence and from the part process of gumbel s first extreme value distribution all show small systematic differences in forecasts but all three methods lead to magnitude forecasts which fall well within the range of standard deviation however these forecasts are obtained by subdividing turkish seismicity in a cellular manner and many of these cells show curvature of the earthquake frequency magnitude distribution curve concave with respect to the origin gumbel s third asymptotic distribution of extreme values is chosen as an appropriate statistical description approximate upper bounds o to earthquake surface wave magnitude occurrence are evaluated and estimates of largest magnitudes expected over an interval of 75yr are forecast with uncertainties values of w are asymptotic uncertain and theoretically correspond to infinite return periods strain energy release diagrams are then invoked to estimate empirically the large magnitude m which is equivalent to the total strain energy which may be accumulated in a region this equivalent magnitude m is consistently less than w and there is a finite waiting time typically ranging from about 15 to 70 yr during which the energy equivalent to m3 may be accumulated

historical earthquake activity of the northern part of the dead sea fault zone southern turkey abstract the northern part of the dead sea fault zone is one of the major active neotectonic structures of turkey the main trace of the fault zone called hacipasa fault is mapped in detail in turkey on the basis of morphological and geological evidence such as offset creeks fault surfaces shutter ridges and linear escarpments three trenches were opened on the investigated part of the fault zone trench studies provided evidence for 3 historical earthquakes and comparing trench data with historical earthquake records showed that these earthquakes occurred in 859 ad 1408 and 1872 field evidence palaeoseismological studies and historical earthquake records indicate that the hacipasa fault takes the significant amount of slip in the northern part of the dead sea fault zone in turkey on the basis of palaeoseismological evidence it is suggested that the recurrence interval for surface faulting event is 506 42 years on the hacipasa fault

active tectonics and human survival strategies tectonic movements continuously remould the surface of earth in response to plate motion yet such deformation is rarely taken into account when assessing landscape change and its impact on human land use except perhaps as an occasional hazard to human life or a temporary disruption in the longer term parems of human history however active tectonics also create and sustain landscapes that can be beneficial to human survival forming a complex topography of potentially fertile sedimentary basins enclosed by mountain bard that can facilitate the control and exploitation of food resources especially animal prey we discuss the tectonic history of northwest greece and show how the paleolithic sites of the region are located to take advantage of tectonically created features at both a local and a regional scale we suggest that the association of significant concentrations of early paleolithic sites with tectonically active regions is not coincidental and that on the longer time spans of human biological evolution active tectonics has been an importam selective agent contributing to the development of the human species as an intelligent predator

rate of strike slip motion on the amanos fault karasu valley southern turkey constrained by k ar dating and geochemical analysis of quaternary basalts the left lateral amanos fault follows a 200 km long and up to 2 km high escarpment that bounds the eastern margin of the amanos mountain range and the western margin of the karasu valley in southern turkey just east of the northeastern corner of the mediterranean sea regional kinematic models have reached diverse conclusions as to the role of this fault in accommodating relative motion between either the african and arabian turkish and african or turkish and arabian plates local studies have tried to estimate its slip rate by k ar dating quaternary basalts that erupted within the amanos mountains flowed across it into the karasu valley and have since become offset however these studies have yielded a wide range of results ranging from 0 3 to 15 mm a 1 which do not allow the overall role and significance of this fault in accommodating crustal deformation to be determined we have used the cassignol k ar method to date nine quaternary basalt samples from the vicinity of the southern part of the amanos fault these basalts exhibit a diverse chemistry which we interpret as a consequence varying degrees of partial melting of their source combined with variable crustal contamination this dating allows us to constrain the quaternary slip rate on the amanos fault to 1 0 to 1 6 mm a 1 the dramatic discrepancies between past estimates of this slip rate are partly due to technical difficulties in k ar dating of young basalts by isotope dilution in addition previous studies at the key locality of hacilar have unwittingly dated different chemically distinct flow units of different ages that are juxtaposed this low slip rate indicates that at present the amanos fault takes up a small proportion of the relative motion between the african and arabian plates which is transferred southward to the dead sea fault zone it also provides strong evidence against the long standing view that its slip continues offshore to the southwest along a hypothetical left lateral fault zone located south of cyprus

kinematics of the amanos fault southern turkey from ar ar dating of offset pleistocene basalt flows transpression between the african and arabian plates

earthquake clustering in the eastern mediterranean during historical times most coastal sectors which show evidence of holocene coseismic uplift in greece and the eastern mediterranean were raised during a short period called here the early byzantine tectonic paroxysm ebtp between the middle of the fourth and the middle of the sixth century a d the areas uplifted at that time include cephalonia and zante in the ionian islands lechaion and the perachora peninsula in the gulf of corinth the pelion coast of thessaly antikythira and the whole of western crete a coastal sector near alanya in southern turkey and the entire levant coast from hatay turkey to syria and the lebanon the amount of the ebtp uplift was generally between 0 5 m and 1 0 m but reached a maximum of about 9 m in southwestern crete in several areas zante pelion coast antikythira western crete alanya the ebtp uplifted shoreline is the only evidence of holocene emergence in other areas however a similar uplift occurred earlier in the holocene levant coast or more recently cephalonia evidence of preseismic subsidence prior to the ebtp uplift has been reported from thessaly antikythira and crete in both the latter islands the ebtp uplift was preceded by a series of about 10 coseismic small subsidence movements each measuring some tens of centimeters which took place in the preceding 3000 years no evidence was observed of postseismic vertical displacements

distribution of interseismic coupling along the north and east anatolian faults inferred from insar and gps data the north anatolian fault naf has produced numerous major earthquakes after decades of quiescence the mw 6 8 elazig earthquake january 24 2020 has recently reminded us that the east anatolia

present day seismicity and seismotectonics of the cilician basin eastern mediterranean region of turkey the nature of the interaction between the anatolian arabian and af rican plates is an important problem of northeastern mediterranean tectonics the dead sea fault and east anatolian fault zone are the most prominent structural elements in this region the cilician basin which is located at the junction of these faults is known to have a very active seismic history however instrumental obser vations have been insufficient because of the lack of an adequate local seismic net work to monitor ongoing seismic activity and to analyze the seismotectonics of the cilician region 36 to 38 n 34 to 38 e a digital seismic network of 18 stations with velocity transducers has been operated by the earth and marine sciences re search institute emsri of the scientific and technical research council of turkey tubitak since 1993 no previous studies have been carried out in this region for crustal structure an optimum 1d velocity model was obtained by using the velest algorithm for reliable determination of earthquake hypocenter locations approxi mately 2500 earthquakes detected between 1993 and 2002 with local magnitude greater than 1 5 have been located by using this optimum velocity model the most notable feature of the epicentral distribution is the presence of dense clusters of activity along local fault trends the majority of hypocentral depths of the events range between 5 and 35 km single fault plane solutions of reliable events were calculated in order to analyze the seismotectonic characteristics of the region results show that the cilicia region constitutes a wide left lateral shearing zone that indicates a diffuse plate boundary between the african arabian and anatolian plates

the 2011 mw 7 1 van eastern turkey earthquake 1 we use interferometric synthetic aperture radar insar body wave seismology satellite imagery and field observations to constrain the fault parameters of the mw 7 1 2011 van eastern turkey reverse slip earthquake in the turkish iranian plateau distributed slip models from elastic dislocation modeling of the insar surface displacements from envisat and cosmo skymed interferograms indicate up to 9 m of reverse and oblique slip on a pair of en echelon nw 40 54 dipping fault planes which have surface extensions projecting to just 10 km north of the city of van the slip remained buried and is relatively deep with a centroid depth of 14 km and the rupture reaching only within 8 9 km of the surface consistent with the lack of significant ground rupture the up dip extension of this modeled wsw striking fault plane coincides with field observations of weak ground deformation seen on the western of the two fault segments and has a dip consistent with that seen at the surface in fault gouge exposed in quaternary sediments no significant coseismic slip is found in the upper 8 km of the crust above the main slip patches except for a small region on the eastern segment potentially resulting from the mw 5 9 aftershock on the same day we perform extensive resolution tests on the data to confirm the robustness of the observed slip deficit in the shallow crust we resolve a steep gradient in displacement at the point where the planes of the two fault segments ends are inferred to abut at depth possibly exerting some structural control on rupture extent

the 1759 earthquake in the bekaa valley implications for earthquake hazard assessment in the eastern mediterranean region analysis of macroseismic data based on primary sources for large though infrequent historical earthquakes ms 6 5 that occurred along an approximately 350 km long segment of the northern part of the dead sea fault system primarily in lebanon and syria for the period 1100 1988 reveals the following 1 ten events occurred in three relatively short periods tens of years with repeat times of 200 350 years 2 the events most probably broke this north segment of the dead sea fault system possibly including the westernmost segment of the east anatolian fault system near the border between syria and turkey 3 the lack of such large events during the past 100 years should not be interpreted to minimize potential earthquake hazard in this region and 4 the ms 7 plus earthquake on november 25 1759 almost certainly produced surface faulting probably along the yammouneh fault in the bekaa valley and caused heavy destruction with great loss of life in numerous villages and towns including safad damascus beirut and baalbek this main event was preceded by a ms 6 plus foreshock on october 30 1759 in the southern part of the epicentral area of the main shock near the towns of safad and qunaitra which were almost totally destroyed with considerable loss of life

irregular earthquake cycle along the southern tianshan front aksu area china 1 a long deformation record 16 5 ka showing nonsteady earthquake recurrence is established for the aksu thrust tianshan china on the basis of cosmogenic 10be dating of faulted surfaces topographic leveling across the aksu fault scarp indicates up to 10 m uplift across a moraine abandoned 16 5 ka and similar uplift of 6 m across two inset surfaces yielding ages of 12 5 and 5 ka successively smaller uplifts of terraces younger than 5 ka indicate that three or more major earthquakes occurred during this period these data show that the aksu thrust fault was quiet for at least 7500 years and active in the last 5000 years and probably in the interval 16 5 12 5 ka the seismic cycle along the aksu thrust fault over the last 16 500 years was thus strongly irregular showing long quiescence and clustering which is a challenge for paleoseismology and hazard assessment this irregularity also makes it more difficult to estimate long term shortening rates nevertheless we are able to constrain a minimum total shortening rate 7 mm yr across the southern tianshan front for the last 12 500 years that is about a third of the total geodetic rate for the western tianshan 20 mm yr

normal stress effects in the creep of ice une solution analytique exacte du fluage biaxial d un fluide non lineaire est comparee aux donnees de quatre tests sur de la glace polycristalline le modele donne une excellente representation a la fois du fluage primaire et secondaire

flow dynamics at the origin of thin clayey sand lacustrine turbidites examples from lake hazar turkey turbidity currents and their deposits can be investigated using several methods i e direct monitoring physical and numerical modelling sediment cores and outcrops the present study focused on thin clayey sand turbidites found in lake hazar turkey occurring in eleven clusters of closely spaced thin beds depositional processes and sources for three of those eleven clusters are studied at three coring sites bathymetrical data and seismic reflection profiles are used to understand the specific geomorphology of each site x ray thin sections and ct scan imagery combined with grain size geochemical and mineralogical measurements on the cores allow characterization of the turbidites turbidites included in each cluster were produced by remobilization of surficial slope sediment a process identified in very few studies worldwide three types of turbidites are distinguished and compared with deposits obtained in flume studies published in the literature type 1 is made of an ungraded clayey silt layer issued from a cohesive flow type 2 is composed of a partially graded clayey sand layer overlain by a mud cap attributed to a transitional flow type 3 corresponds to a graded clayey sand layer overlain by a mud cap issued from a turbulence dominated flow while the published experimental studies show that turbulence is damped by cohesion for low clay content type 3 deposits of this study show evidence for a turbulence dominated mechanism despite their high clay content this divergence may in part relate to input variables such as water chemistry and clay mineralogy that are not routinely considered in experimental studies furthermore the large sedimentological variety observed in the turbidites from one coring site to another is related to the evolution of a sediment flow within a field scale basin made of a complex physiography that cannot be tackled by flume experiments

regional structure and polyphased cretaceous paleocene rift and basin development of the mid norwegian volcanic passive margin abstract the more and voring basins of the mid norwegian volcanic passive margin are characterized by thick accumulations of cretaceous to paleocene sedimentary strata they were formed during a series of late mesozoic early cenozoic extensional events and represent vast underexplored areas with a limited number of wells recently a new generation of long offset 2d seismic reflection lines and 3d seismic data together with new well data has permitted a significant improvement in the regional understanding of the more and voring basins this has enabled much better imaging of the deep cretaceous subbasins and sub basalt structures in light of this significant data improvement we performed a regional tectonostratigraphic synthesis of the pre breakup development of the more and voring basins we have interpreted eight regional cretaceous and paleocene horizons and constructed a series of structural and thickness maps the new interpretations allow us to examine the sequential evolution of the cretaceous to paleocene sedimentary infill and to discuss its relationship to the deep crustal structures and regional tectonic events we conclude that the long and polyphased development of the more and voring basins is partly controlled by deep seated structural highs we show that active deposition in the early cretaceous was mainly focused in the more basin while the main cenomanian and subsequent late cretaceous paleocene depocentres developed principally in the voring basin and migrated sequentially west towards the present continent ocean boundary we argue that the outer more and voring basins are likely underlain by a relatively thick continental crust compared to the inner part of the regional sag basin in this setting our observations do not support evidence for a large zone of exhumed upper mantle which has previously been proposed to have formed before magmatism and breakup

active tectonics of the alpine himalayan belt between western turkey and pakistan summary over 80 new fault plane solutions combined with satellite imagery as well as both modern and historical observations of earthquake faulting are used to investigate the active tectonics of the middle east between western turkey and pakistan the deformation of the western part of this region is dominated by the movement of continental material laterally away from the lake van region in eastern turkey this movement helps to avoid crustal thickening in the van region and allows some of the shortening between arabia and eurasia to be taken up by the thrusting of continental material over oceanic type basement in the southern caspian mediterranean makran and black sea thus central turkey bounded by the north and east anatolian strike slip faults is moving west from the van region and overrides the eastern mediterranean at two intermediate depth seismic zones one extending between antalya bay and southern cyprus and the other further west in the hellenic trench the motion of northern iran eastwards from the van region is achieved mainly by a conjugate system of strike slip faults and leads to the low angle thrusting of iran over the southern caspian sea the seismicity of the caucasus shows predominantly shortening perpendicular to the regional strike but there is also some minor elongation along the strike of the belt as the causcasus overrides the caspian and black seas the deformation of the eastern part of this region is dominated by the shortening of iran against the stable borders of turkmenistan and afghanistan the north east direction of compression seen in zagros is also seen in north east iran and the kopet dag where the shortening is taken up by a combination of strike slip and thrust faulting large structural as well as palaeomagnetic rotations are likely to have occurred in ne iran as a result of this style of deformation north south strike slip faults in southern iran allow some movement of material away from the collision zone in ne iran towards the makran subduction zone where genuinely intermediate depth seismicity is seen within this broad deforming belt large areas such as central turkey nw iran azerbaijan central iran and the southern caspian appear to be almost aseismic and therefore to behave as relatively rigid blocks surrounded by active belts 200 300 km wide the motion of these blocks can usefully be described by poles of rotation the poles presented in this paper predict motions consistent with those observed and also predict the opening of the gulf of iskenderun ne of cyprus the change within the zagros mountains from strike slip faulting in the nw to intense thrusting in the se and the relatively feeble seismicity in se iran baluchistan this description also explains why the north south structures along the iran afghanistan border do not cut the east west ranges of the makran within the active belts surrounding the relatively aseismic blocks a continuum approach is needed for a description of the deformation even though motions at the surface may be concentrated on faults the evolution of fault systems within the active zones is controlled by geometric constraints such as the requirement that simultaneously active faults do not in general intersect many of the active processes discussed in this paper particularly large scale rotations and lateral movement along the regional strike are likely to have caused substantial complexities in older mountain belts and should be accounted for in any reconstructions of them

the 2020 mw 6 8 elazig turkey earthquake reveals rupture behavior of the east anatolian fault the 2020 mw 6 8 elazig earthquake was the largest along the eastern anatolian fault eaf in over a century and so provides valuable insights into its rupture behavior because the eaf is of low to

the earthquake of 1546 in the holy landz the earthquake of 1546 is considered to be one of the largest shocks in the middle east associated with surface faulting and great loss of life the examination of contemporary documents shows that this seismic event was a medium magnitude earthquake of ms about 6 0 in many respects similar to that of the earthquake of 1927 that is one of those early and grossly exaggerated events which excited widespread interest rather on account of the geographical location than because of their size or special violence we cpud find no evidence of faulting or excessive damage and no justification to regard this earthquake as one of the most destructive in the jordan rift valley

temporary seismic quiescence se turkey summary the border zone that is the contact of the arabian plate with the three plates of turkey eurasia and iran to the north has been remarkably aseismic during this century by extending the period of observation backwards in time by a few centuries it is shown that this seismicity is atypical of the long term behaviour of the zone and due to a quiescent period in the activity of the area during the 20th century in turn this implies that short term data alone do not provide a reliable assessment of earthquake hazard

source parameters of large earthquakes in the east anatolian fault zone turkey summary the east anatolian fault zone accommodates most of the motion between the arabian plate and the apparently little deforming interior of central turkey the direction of overall slip across this zone is crucial to the determination of the slip rate on the north anatolian fault we use long period p and sn waveforms to determine the source parameters of the four largest earthquakes that occurred in or near the east anatolian fault zone in the last 35 years only one of these actually involved left lateral strike slip motion on a ne sw fault but the other three and the nearby 1975 lice earthquake all had steeply dipping nodal planes with a nnw strike if these were the auxiliary planes then all the earthquakes had a slip vector direction within about 10 of 063 if this direction represents the arabia turkey motion then the slip rate on the north anatolian fault must be in the range 31 to 48 mm yr with a probable value of 38 mm yr and the overall slip rate across the east anatolian fault zone must be about 29mmyr with a range of 25

block like plate movements in eastern anatolia observed by insar 1 the question whether continental plates deform internally or move as rigid blocks has been debated for several decades to further address this question we use large scale interferometric synthetic aperture radar insar data sets to study how eastern anatolia and its surrounding plates deform we find that most of the deformation is focused at the north and east anatolian faults and little intraplate deformation takes place anatolia is therefore moving at least its eastern part as a uniform block we estimate the slip velocity and locking depth of the north anatolian fault at this location to be 20 mm yr and 14 km respectively high deformation gradient found near the east anatolian fault on the other hand suggests that little stress is accumulating along the eastern sections of that fault

the regional time and magnitude predictable model and its application to the alpine himalayan belt abstract the regional time and magnitude predictable model has been introduced and has been shown to be appropriate to describe the behaviour in the occurrence of mainshocks the model implies that the magnitude of the preceding mainshock in a seismogenic region that is the largest earthquake during a seismic excitation governs the time of occurrence and the magnitude of the expected mainshock in this region this model has been applied in 149 seismogenic regions of the alpine himalayan seismic belt the model probability for the occurrence of the next very strong main shock ms 6 5 during the decade 1993 2002 as well as the magnitude of this shock in each of these regions have been calculated furthermore two tests have been performed to check the validity of this model these tests have shown the reliability of the model and its superiority compared to the classical time independent model

stress accumulation and increased seismic risk in eastern turkey abstract unlike the north anatolian fault zone which has produced 11 large earthquakes since 1939 the east anatolian fault zone eafz has been relatively quiescent in the last century when compared to historical records and has therefore accumulated significant stresses along its length determination of the location and likely magnitude of a future probable earthquake along the eafz is of interest both because of this history of large earthquakes m 8 and the density of population in the area here we calculate stress evolution along the fault zone due to both seismic and tectonic loading since 1822 a sequence of 10 well constrained historical earthquakes is selected and the resulting stresses are calculated summed with tectonic loading stresses and resolved onto the mapped active faults we identify two areas of particular seismic risk one of which might be expected to yield a large event our results are sensitive to the previous history of large earthquakes in the region and indicate a need for detailed investigations to constrain the exact rupture geometries of previous earthquakes on these segments

source inversion of the 1993 and 1995 gulf of aqaba earthquakes abstract the teleseismic body waves of two earthquakes were inverted to their sources so as to obtain a rupture process for each the events of august 3 1993 m s 6 1 and november 22 1995 m s 7 2 took place at the southern end of the dead sea fault system dsfs which has been seismically quiet for the last few centuries the inversion results show that the rupture of the 1995 event originated in the vicinity of the 1993 event and propagated to the north where the major moment release of two subevents took place the first being 20 km and the second being 40 km away the seismic moment of the first and second subevents were m o 7 4 10 18 nm and m o 38 10 18 nm respectively despite their proximity they show completely different focal mechanisms the first subevent has a predominantly normal faulting mechanism like the 1993 event which probably took place on the faults forming the pull apart basins beneath the gulf of aqaba the major subevent shows a predominantly left lateral strike slip mechanism which clearly identifies the dsfs as accommodating the motion between africa and arabia we attribute the abrupt change of the mechanisms of the 1993 and 1995 events to segmentation of the dsfs beneath the gulf of aqaba which probably gave rise to an extensional regime the locations of the 1993 and 1995 earthquakes their aftershock distribution and the spatial distribution of the subevents of the 1995 earthquake show end to end migration of sources from south to north taking into account the long seismic quiescence of the dsfs and the source inversion results one may conclude that the area to the north of the rupture zone of the 1995 event is prone to a large earthquake