tectonic evolution of the gediz graben field evidence for an episodic two stage extension in western turkey western turkey is one of the most spectacular regions of widespread active continental extension in the world the most prominent structures of this region are e w trending grabens e g gediz and buyuk menderes grabens and intervening horsts exposing the menderes massif this paper documents the result of a recent field campaign field geological mapping and structural analysis along the southern margin of the modern gediz graben of pliocene 5 ma age this work provides field evidence that the presently low angle ductile brittle detachment fault is cut and displaced by the high angle graben bounding normal faults with total displacement exceeding 2 0 km the evolution of the n s extension along the gediz graben occurred during two episodes each characterized by a distinct structural styles 1 rapid exhumation of menderes massif in the footwall of low angle normal fault core complex mode during the miocene 2 late stretching of crust producing e w grabens along high angle normal faults rift mode during pliocene quaternary times separated by a short time gap the later phase is characterized by the deposition of now nearly horizontal sediments of pliocene age in the hanging walls of the high angle normal faults and present day graben floor sediments the evolution of extension is at variance with orogenic collapse and or back arc extension followed by the combined effect of tectonic escape and subduction rollback processes along the aegean cyprean subduction zone consequently it is misleading to describe the miocene sediments exhumed on shoulders of the gediz graben as simple graben fill

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

the preservation of seismic anisotropy in the earth s mantle during diffusion creep summary seismic anisotropy in the earth particularly in the mantle is commonly interpreted as the result of solid state deformation by dislocation creep that induces a lattice preferred orientation lpo diffusion creep operates where stress levels are lower and or grain sizes smaller it is often assumed that diffusion creep induces grain rotations that eventually destroy any existing lpo a new numerical test of this assumption shows that it is not necessarily the case diffusion creep will create some relative grain rotations but rotation rates decrease through time hence when microstructural change due to diffusion creep dominates that due to grain growth defined here as type p behaviour the converse being type o behaviour the model indicates that lpo will be weakened but preserved for a variety of strain paths including both pure and simple shear one measure of anisotropy is the proportional difference in shear wave velocities for different polarization vectors avs a model olivine microstructure with equant grains and initial maximum avs of 10 0 percent has this value reduced to 6 7 per cent when rotational steady state is attained other models with different initial maximum avs values exhibit final maximum avs values more than half the initial values if the grains are initially elongate by a factor of 2 maximum avs is reduced just slightly to 8 5 per cent thus when grain growth plays a subordinate role to the deformation diffusion creep weakens seismic anisotropy by a factor of less than 2 using maximum avs as a measure and olivine as an example consequently the link between seismic anisotropy and deformation mechanism in the mantle requires reappraisal regions with lpo may comprise material which once deformed by dislocation creep but is now deforming by diffusion creep in a rotational steady state

probabilistic appraisal of earthquake hazard parameters deduced from a bayesian approach in the northwest frontier of the himalayas a straightforward bayesian statistic is applied in five broad seismogenic source zones of the northwest frontier of the himalayas to estimate the earthquake hazard parameters maximum regional magnitude mmax value of g r relationship and seismic activity rate or intensity for this purpose a reliable earthquake catalogue which is homogeneous for mw 5 0 and complete during the period 1900 to 2010 is compiled the hindukush pamir himalaya zone has been further divided into two seismic zones of shallow h 70 km and intermediate depth h 70 km according to the variation of seismicity with depth in the subduction zone the estimated earthquake hazard parameters by bayesian approach are more stable and reliable with low standard deviations than other approaches but the technique is more time consuming in this study quantiles of functions of distributions of true and apparent magnitudes for future time intervals of 5 10 20 50 and 100 years are calculated with confidence limits for probability levels of 50 70 and 90 in all seismogenic source zones the zones of estimated mmax greater than 8 0 are related to the sulaiman kirthar ranges hindukush pamir himalaya and himalayan frontal thrusts belt suggesting more seismically hazardous regions in the examined area the lowest value of mmax 6 44 has been calculated in northern pakistan and hazara syntaxis zone which have estimated lowest activity rate 0 0023 events day as compared to other zones the himalayan frontal thrusts belt exhibits higher earthquake magnitude 8 01 in next 100 years with 90 probability level as compared to other zones which reveals that this zone is more vulnerable to occurrence of a great earthquake the obtained results in this study are directly useful for the probabilistic seismic hazard assessment in the examined region of himalaya

an evaluation of earthquake hazard potential for different regions in western anatolia using the historical and instrumental earthquake data we applied the maximum likelihood method produced by kijko and sellevoll bull seismol soc am 79 645 654 1989 bull seismol soc am 82 120 134 1992 to study the spatial distributions of seismicity and earthquake hazard parameters for the different regions in western anatolia wa since the historical earthquake data are very important for examining regional earthquake hazard parameters a procedure that allows the use of either historical or instrumental data or even a combination of the two has been applied in this study by using this method we estimated the earthquake hazard parameters which include the maximum regional magnitude hat m max the activity rate of seismic events and the well known hat b value which is the slope of the frequency magnitude gutenberg richter relationship the whole examined area is divided into 15 different seismic regions based on their tectonic and seismotectonic regimes the probabilities return periods of earthquakes with a magnitude m m and the relative earthquake hazard level defined as the index k are also evaluated for each seismic region each of the computed earthquake hazard parameters is mapped on the different seismic regions to represent regional variation of these parameters furthermore the investigated regions are classified into different seismic hazard level groups considering the k index according to these maps and the classification of seismic hazard the most seismically active regions in wa are 1 8 10 and 12 related to the aliaga fault and the buyuk menderes graben aegean arc and aegean islands

estimating earthquake hazard parameters from instrumental data for different regions in and around turkey abstract we conducted a study of the spatial distributions of seismicity and earthquake hazard parameters for turkey and the adjacent areas applying the maximum likelihood method the procedure allows for the use of either historical or instrumental data or even a combination of the two by using this method we can estimate the earthquake hazard parameters which include the maximum regional magnitude m max the activity rate of seismic events and the well known b value which is the slope of the frequency magnitude gutenberg richter relationship these three parameters are determined simultaneously using an iterative scheme the uncertainty in the determination of the magnitudes was also taken into consideration the return periods rp of earthquakes with a magnitude m m are also evaluated the whole examined area is divided into 24 seismic regions based on their seismotectonic regime the homogeneity of the magnitudes is an essential factor in such studies in order to achieve homogeneity of the magnitudes formulas that convert any magnitude to an m s surface scale are developed new completeness cutoffs and their corresponding time intervals are also assessed for each of the 24 seismic regions each of the obtained parameters is distributed into its respective seismic region allowing for an analysis of the localized seismicity parameters and a representation of their regional variation on a map the earthquake hazard level is also calculated as a function of the form m max rp 6 0 and a relative hazard scale defined as the index k is defined for each seismic region the investigated regions are then classified into five groups using these parameters this classification is useful for theoretical and practical reasons and provides a picture of quantitative seismicity an attempt is then made to relate these values to the local tectonics

the determination of earthquake hazard parameters deduced from bayesian approach for different seismic source regions of western anatolia the bayesian method is used to evaluate earthquake hazard parameters of maximum regional magnitude mmax value and seismic activity rate or intensity and their uncertainties for the 15 different source regions in western anatolia a compiled earthquake catalog that is homogenous for ms 4 was completed during the period from 1900 to 2013 the computed mmax values are between 6 00 and 8 06 low values are found in the northern part of western anatolia whereas high values are observed in the southern part of western anatolia related to the aegean subduction zone the largest value is computed in region 10 comprising the aegean islands the quantiles of functions of distributions of true and apparent magnitude on a given time interval 0 t are evaluated the quantiles of functions of distributions of apparent and true magnitudes for future time intervals of 5 10 20 50 and 100 years are calculated in all seismogenic source regions for confidence limits of probability levels of 50 70 and 90 according to the computed earthquake hazard parameters the requirement leads to the earthquake estimation of the parameters referred to as the most seismically active regions of western anatolia the aegean islands which have the highest earthquake magnitude 7 65 in the next 100 years with a 90 probability level is the most dangerous region compared to other regions the results found in this study can be used in probabilistic seismic hazard studies of western anatolia

timing of tectonic events in the menderes massif western turkey implications for tectonic evolution and evidence for pan african basement in turkey the menderes massif forms the western of the two large metamorphic culminations within the turkish alpide orogen it has three major lithologic units with a gneissic core at the base and a schist and a marble envelope overlying it successively although relations between them have been largely obscured by the polymetamorphic and structurally complex history of the massif we present a review of the available stratigraphic evidence and combine it with new isotopic ages from the central and southern parts of the massif to constrain the timing of major tectonic events that shaped the massif since the late proterozoic pt3 in the southern part of the massif sensu stricto three episodes of deformation and metamorphism are distinguished whereas in its northern part there are four the first episode occurred at 500 10 ma with intense deformation and metamorphism at high grade amphibolite facies with local anatexis in the central part of the massif the 470 9 ma old now highly deformed tonalitic and granitic intrusions mark the end of this episode on a cambrian reconstruction of continents around the eastern mediterranean the menderes massif forms the southern end of the pan african orogenic collage of northeastern africa and arabia the area of earliest palaeozoic deformation in the menderes may connect with the northwest african orogenic collage along the strike via the bozburun and saricicek diabases arkoses and schists in the center of the karacahisar dome interpreted herein as fragments of a pan african suture the earliest palaeozoic deformations to affect the rocks were probably related to the last pan african collisions and associated postcollisional convergence the southern part of the massif was undeformed from early ordovician to the early later eocene whereas the northern part was deformed metamorphosed and intruded possibly during the late triassic related to the closure of the karakaya marginal basin of palaeo tethys the next major event affecting the whole of the massif was the intense deformation and widespread metamorphism that reached high amphibolite grade in the structurally lower parts and only greenschist grade in the outermost envelope this metamorphism here called the main menderes metamorphism mmm is biostratigraphically constrained between early eocene and early oligocene time rb sr isotopic data show a spread of ages between 60 ma and 25 ma with the greatest number of determinations around 35 5 ma this number is in excellent agreement with the stratigraphic evidence and shows that mmm took place during latest eocene time or at the transition from eocene to oligocene time along the northern border of the massif deformation and metamorphism had already taken place during the late cretaceous in a high pressure low temperature hp lt metamorphic belt northernmost part of menderes massif sensu lato which was then covered by palaeocene molasse the evolution of the hp lt belt was probably related to the obduction of the bozkir ophiolites from the izmir ankara branch of the neo tethys ocean and preceded terminal collision in the evolution of the massif the mmm was a product of the latest palaeocene collision across neo tethys and the consequent internal imbrication of the menderes taurus block that resulted in the burial of the menderes massif area beneath the lycian nappe complex a low grade metamorphic event dated at 10 to 5 ma is interpreted to be related to the extensional deformation in the aegean and western turkey which has been dated stratigraphically to have begun during the tortonian 11 5 ma

first paleomagnetic evidence for a post eocene clockwise rotation of the western taurides thrust belt east of the isparta reentrant southwestern turkey abstract a paleomagnetic study was carried out on 23 sites sampled in paleocene eocene and lower miocene sedimentary formations of the western taurides belt east of the isparta reentrant the paleomagnetic data based on twelve suitable sites record a coherent post eocene 40 clockwise rotation throughout the area studied we interpret this regional rotation as a semi rigid rotation of the whole western taurides belt above a major deep decollement level together with previously published data these new results suggest that the isparta reentrant would result from diachronous opposite rotations of the two branches first a late eocene oligocene clockwise rotation of the akseki beysehir taurides initiating the tauride arc and then anticlockwise rotation of the lycian taurides probably during middle miocene times

neotectonic structures in izmir gulf and surrounding regions western turkey evidences of strike slip faulting with compression in the aegean extensional regime abstract of single channel 70 km and 900 km of multi channel seismic reflection data show that izmir gulf and surrounding regions are widely deformed by n s to ne sw trending active transpressional strike slip faults reverse faults and some e w normal faults normal faults are mapped offshore karaburun foca in inner part of izmir gulf offshore alacati teke and offshore kusadasi delimiting the southern scarp of lesvos basin izmir basin northern scarp of ikaria basin and continuation of kucuk menderes graben respectively normal faults are cut by strike slip faults the major strike slip faults are the n s oriented karaburun reverse fault bordering izmir gulf on the west and uplifting the karaburun peninsula and the ne sw oriented strike slip tuzla fault extending from doganbey promontory towards seferihisar ridge onland this fault pattern can be explained by pure shear model indicating that the area is under e w compression n s extension ne sw and nw se strike slip deformation moreover tuzla fault has a regional importance it separates ne sw trending structures of the study area from e w oriented gediz and kucuk menderes grabens and probably continues towards to iznik at north constituting a transition zone between northern transpressional region and southern extensional region in the western anatolia aegean sea

late cenozoic volcanic evolution of the northeastern aegean region abstract late cenozoic volcanism occurred in an extensional tectonic regime in the northeastern aegean activity commenced in northeastern greece during the early oligocene and in northwestern turkey during the late oligocene early miocene the beginning of activity was characterized by calc alkaline intermediate acid volcanism however alkaline intermediate basic volcanism became dominant from the late miocene until the pleistocene this change in nature of volcanism is not related to a change of regional tectonic regime as previously thought instead we propose that the volcanic evolution reflects an increasing asthenospheric contribution facilitated by a thinned extended lithosphere arising from the regional extensional tectonics

how pore fluid pressurization influences crack tip processes during dynamic rupture 1 we calculate temperature and pore pressure rises along a steadily propagating shear crack assuming a given shear stress profile along the crack i e initially neglecting effects of pore pressure on shear stress in the limit of a singular crack temperature and pore pressure rises are a step function in time we verify that pore pressure can indeed be neglected at the tip and in the cohesive zone of the crack in the case of strong velocity weakening of the friction coefficient e g as governed by flash heating of asperities like analyzed in a recent numerical simulation of spontaneous rupture in such cases the local fracture energy needed to increase the crack length is thus likely to be governed by dry frictional processes with effective slip weakening distance of the order of 20 m while thermal pressurization may affect the later stages of slip and hence the overall fracture energy attributed to the propagating rupture

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

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

bayesian analysis of extreme earthquake occurrences part i probabilistic hazard model bayesian probability theory in conjunction with the model of extremes is used to develop a bayesian distribution of extreme earthquake occurrences by assuming that earthquakes represent a poisson process with exponential distribution of magnitudes the bayesian distribution represents the probability that m max the largest earthquake expected to occur within a period of t years will exceed some specified magnitude m and may be computed from the relationship p m max m t 1 t t t 1 f m n where n and t represent updated posterior bayesian estimates of the number of earthquakes and the time period of observation respectively and f m is the bayesian distribution of magnitudes each updated from prior estimates of seismicity using historical observations of earthquake occurrences through the application of bayesian probability theory the above distribution contains two features that make it more powerful and reliable than the conventional extreme value distribution first it incorporates statistical uncertainty in the estimation of seismicity in addition to the inherent uncertainty associated with the random nature of earthquake occurrences second it provides a rigorous means of combining prior information on seismicity such as geologica data with available historical observations of earthquake occurrences the last feature represents a major step toward the ability of earthquake engineers to systematically use information from geologists and seismologists regarding the seismic potential of faults and small regions in the probabilistic assessment of seismic hazards and provides a means of periodically updating estimates of earthquake occurrence probabilities as new seismicity data become available

timing of cenozoic extensional tectonics in west turkey the timing of the transition from compressional to extensional tectonics in the late cenozoic evolution of west turkey has been constrained by k ar geochronology from acidic volcanic rocks and tourmaline leucogranite dykes in the central and east margin respectively of the gordes basin dacites and rhyolites in the centre of the gordes neogene sedimentary basin cut both the basement ophiolites of the izmir ankara suture zone and the neogene sediments on the basin s eastern margin the leucogranites cut metamorphic basement along a major ne sw trending normal fault that controls the regional structure of the basin pebbles of these leucogranites occur in adjacent neogene turfites and conglomerates k ar dates on biotites from the central volcanic rocks vary from 18 4 0 8 ma to 16 3 0 5 ma early miocene whilst muscovite from a leucogranite on the eastern margin of the basin provides ages of 24 2 0 8 ma and 21 1 1 1 ma latest oligocene to early miocene geochronological data and field relationships demonstrate that the earlier compressional regime had been replaced by extensional tectonics by latest oligocene early miocene

the effect of rain in calming the sea abstract the effect of rain in damping surface waves appears to be significant in the estimation of wind speed from the backscatter of radar signal from the sea surface the radar backscatter depends on the small scale roughness of the sea surface this is modified by the generation of capillary and gravity capillary ripples by raindrops and by the increased damping of the wavelengths of 10 cm scale the phenomenon is also important in wave generation and wave breaking since in both cases the short wavelengths play a key role a laboratory experiment has been performed to investigate the damping of water waves by rain in the absence of wind rain of intensity of 300 mm h 1 falls on mechanically generated progressive waves the wave amplitude is measured before the wave enters and after it exits the rain section of a tank 2 35 m long on the assumption of exponential damping it is found that the effect of rain can be described by an eddy viscosity e 0 3 cm2 s 1 the major part of the damping is attrib

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

second order moment of central california seismicity 1969 1982 the second order moment cross correlation function of earthquakes in the u s geological survey central california catalog between 1969 and 1982 was calculated with respect to a magnitude threshold m 4 0 over interevent distances up to 80 km and interevent times up to 320 days the statistical procedure results in a representation of the spatial temporal structure of the catalog associated with m 4 0 earthquakes and is capable of revealing patterns too weak to be detected in the space time distribution of seismicity for individual earthquake sequences a method is introduced for identifying aftershocks based on a physical two parameter model of the earthquake interaction process the results show that the aftershock process dominates the second order moment and may even obscure the statistical expression of a precursory process a concentration of foreshocks within 15 km and 3 days of m 4 0 main shocks exhibits an apparent migration toward the main shock loci with velocity 2 6 5 3 km d this concentration may be related to an observed tendency for m 4 0 events to cluster auto correlate over this interevent range with the identified aftershocks removed the residual catalog is poissonion in space and time when two m 4 0 earthquakes occur within 80 km and 40 days of each other aftershock productivity appears to be relatively enhanced in the earlier sequence this suggests that aftershock populations are not solely dependent on their main shocks and that unusually productive aftershock sequences may be predictors of future moderate earthquakes

earthquake hazard parameters in crete island and its surrounding area inferred from bayes statistics an integration of morphology of the seismically active structures and seismological data the study addresses the evaluation of earthquake hazard parameters such as maximum regional magnitude mmax and the slope of gutenberg richter law where b log e for the hellenic wadati benioff zone and the overriding lithospheric plate in the area of crete and its surroundings the seismicity of the area is divided in a cellular 1 0 1 0 manner allowing analysis of the localized earthquake hazard parameters and graphical representation of their spatial variation our approach incorporates the recently updated earthquake catalogue for greece and the adjacent areas the consideration of the morphology of the deep seismically active structures in the studied area and use of a probabilistic procedure for estimating the earthquake hazard parameters one of the main inconsistencies in the earthquake hazard assessment is the estimation of the maximum magnitude and the related uncertaint y the bayesian approach applied in the present is a straightforward technique for evaluating the earthquake hazard parameters and is based on the following assumptions poissonian character of seismic events flow a frequency magnitude law of gutenberg richter s type with cutoff maximal value for estimated parameter and a seismic catalogue having a rather sizeable number of events i e 50 events at least per cell for five cells in which the number of events is less than 50 an effort is made to produce synthetic data the re assessed parameters obtained from the synthetic data show no significant difference and the real data of the five cells are finally taken into account although the estimated uncertainty is high for four random cells we constructed hazard curves showing the probabilities that a certain magnitude m will be exceeded in one year and the return periods in years that are expected for a given magnitude these are particularly useful for the mapping of earthquake hazard in regions of either low or high seismic activity as is crete and the adjacent area the obtained results show that the w and e parts of both subducting and overriding plates differ in the spatial distribution of all the estimated earthquake hazard parameters the mmax distribution indicates strong coupling between the western portions of the interacting plates mmax 6 3 to the south of 36 n the smaller values of mmax mmax 1 0 are found to the south and east of crete for the wadati benioff zone and over the central part of the island and the area to the northeast of it cell 11 for the continental wedge which suggests nonuniform stress field and or heterogeneous material

neotectonic structures in the area offshore of alacati doganbey and kusadasi western turkey evidence of strike slip faulting in the aegean extensional province abstract about 400 km of new seismic reflection data has been acquired in the study region offshore of alacati doganbey and kusadasi which enables investigation of the active crustal deformation in this region the deformation onshore in western turkey is dominated by crustal extension and clear evidence of this process is also now available from this offshore area however in the onshore area adjacent to this study region evidence of active right lateral strike slip faulting has also previously been observed this strike slip faulting has previously been thought only to accommodate variations in extension between adjacent normal faults however in the offshore area there is considerable evidence of zones of deformation some of which may link to the strike slip faulting onshore suggesting that strike slip faulting may be of greater importance in this region than previously thought

sediment thicknesses of the western anatolia graben structures determined by 2d and 3d analysis using gravity data abstract western turkey is tectonically one of the most active and rapidly deforming regions of continental crust in the world the most pronounced structural and morphological features of this region are defined by normal faulting in an e w direction which creates the boundaries of the buyuk menderes kucuk menderes and gediz grabens the graben systems may have become active between 11 7 ma and are now deeper than the surrounding topography the gediz and buyuk menderes grabens exhibit negative bouguer gravity anomalies the bouguer gravity anomalies increase towards the center of the aegean sea in a regional sense the grabens are filled with recent sediments giving rise to relative negative gravity anomalies these anomalies were interpreted using 2d and 3d gravity inversion techniques in order to determine the depth to the metamorphic basement inversion of geophysical anomalies implies fitting the observed data to theoretical anomalies possibly produced by subsurface bodies inversion of gravity anomalies is a non linear problem in the sense that body parameters are not linearly related to the anomalies gravity anomalies caused by structures are mostly determined by a 2d model which has an n sided polygonal cross section for non linear problems theoretically it is more suitable to determine the parameters of the structure by a series of juxtaposing prisms or vertical dykes extending to infinity rather than using a single n side polygonal model the depths to the top surfaces of a rectangular prisms with infinite depth represent the relief of the basement the basement relief can be computed on the basis of density contrast if the reference depth is assessed as a result of 3d analysis of the bouguer gravity map the maximum thickness of sedimentary cover appears to be more than 2 0 and 1 5 km for the gediz and buyuk menderes grabens respectively towards the saraykoy kizildere area the sedimentary thickness cover thickens to more than 2 0 km 2d analysis of the bouguer gravity profiles indicate that the maximum thickness of the sedimentary cover is between 2 5 and 3 5 km in the buyuk menderes graben and between 0 5 and 2 0 km in the gediz graben

global positioning system constraints on plate kinematics and dynamics in the eastern mediterranean and caucasus we present and interpret global positioning system gps measurements of crustal motions for the period 1988 1997 at 189 sites extending east west from the caucasus mountains to the adriatic sea and north south from the southern edge of the eurasian plate to the northern edge of the african plate sites on the northern arabian platform move 18 2 mm yr at n25 5 w relative to eurasia less than the nuvel 1a circuit closure rate 25 1 mm yr at n21 7 w preliminary motion estimates 1994 1997 for stations located in egypt on the northeastern part of africa show northward motion at 5 6 2 mm yr also slower than nuvel ia estimates 10 1 mm yr at n2 4 e eastern turkey is characterized by distributed deformation while central turkey is characterized by coherent plate motion internal deformation of 2 mm yr involving westward displacement and counterclockwise rotation of the anatolian plate the anatolian plate is de coupled from eurasia along the right lateral strike slip north anatolian fault naf we derive a best fitting euler vector for anatolia eurasia motion of 30 7 0 8 n 32 6 0 4 e 1 2 0 1 myr the euler vector gives an upper bound for naf slip rate of 24 1 mm yr we determine a preliminary gps arabia anatolia euler vector of 32 9 1 2 n 40 3 1 1 e 0 8 0 2 myr and an upper bound on left lateral slip on the east anatolian fault eaf of 9 1 mm yr the central and southern aegean is characterized by coherent motion internal deformation of 2 mm yr toward the sw at 30 1 mm yr relative to eurasia stations in the se aegean deviate significantly from the overall motion of the southern aegean showing increasing velocities toward the trench and reaching 10 1 mm yr relative to the southern aegean as a whole

application of a bayesian approach for estimation of seismic hazard parameters in some regions of the circum pacific belt the maximum possible regional magnitude mmax and other seismic hazard parameters like which is the slope of gutenberg richter law and which is the intensity rate of seismic activity are estimated in eight seismic regions of the west side of the circum pacific belt the bayesian approach as described by pisarenko et al 1996 pisarenko and lyubushin 1997 1999 is a straightforward technique of estimating the seismic hazard the main assumptions for the method applied are a poissonian character of seismic events flow a frequency magnitude law of gutenberg richter s type with cutoff maximum value for the estimated parameter and a seismic catalog which have a rather sizeable number of events we also estimated the quantiles of the probabilistic distribution of the apparent mmax for future given time length intervals

geodetic determination of the kinematics of central greece with respect to europe implications for eastern mediterranean tectonics we use a new satellite laser ranging global positioning system slr gps solution at seven sites in anatolia and aegea to obtain a better definition of the extrusion motion of the anatolian aegean block with respect to europe we show that this motion can be described in a first approximation by a counterclockwise rotation which transfers most of the motion of arabia to anatolia we combine 78 displacement vectors obtained at common points of two triangulation nets measured in central greece in 1895 and 1975 with the slr gps measurements to compute the velocity field over greece with respect to europe these measurements indicate that central greece is a zone of extension between the anatolian aegean counterclockwise rotation to the south and the northern greece clockwise rotation to the north this extension is principally localized within the gulf of corinth to the east but is distributed to the west we then extrapolate this velocity field to the whole aegea and western anatolia using recently published gps results as well as the slr results the narrow dextral north anatolian fault which limits the velocity field to the north progressively gives way to a much wider boundary zone where extension becomes dominant we show that the collision between the mediterranean ridge and africa began 3 6 ma and we describe the modifications that this collision has produced on the kinematic pattern both in aegea and on the mediterranean ridge