present day kinematics of the mediterranean a comprehensive overview of gps results i combine recently published gps results to derive a geodetic horizontal velocity field consistent at the scale of the mediterranean and the surrounding alpine belts the velocity field is then used to discuss the boundary conditions around each major deforming area in the mediterranean to describe the main patterns of motion and deformation to critically review the existing kinematics models and to finally point out the main unresolved kinematics questions strain rate in europe north of the alpines belt is dominated by the signature of the glacial isostatic adjustment and tectonic strain remains below the current accuracy of gps results in the western mediterranean deformation is restricted to the betics the alboran and the morrocan rif with west to southwestward motion with respect to iberia which is part of stable europe shortening consistent with the relative nubia eurasia plate motion is found throughout the maghrebides but the distribution of deformation in northern africa remains largely unknown the central mediterranean is dominated by the counter clockwise rotation of the adriatic the junction between the southern adriatic domain and nubia has yet to be firmly established the deformation over a wide area east of the maghrebides in tunisia and the gulf of sirte in libya still remains to be quantified in the eastern mediterranean the velocity field is dominated by a general anti clockwise rotation and a general trend towards the hellenic trench with velocity magnitude increasing with decreasing distances from the trench this trend is observed not only in the aegean and anatolia but also in the southern balkans geodetic results emphasize that the convergence of the nubia and arabia plates towards eurasia directly controls the deformation across only very few segments along the plate boundary zone additional processes are therefore required to explain the observed velocity field and deformation pattern

from foreland to forearc domains new multichannel seismic reflection survey of the mediterranean ridge accretionary complex eastern mediterranean abstract the mediterranean ridge of the eastern mediterranean sea is a huge accretionary wedge emplaced as a consequence of the africa aegean plate convergence that has a rate estimated at 40 mm yr processing of recent multichannel seismic data and integration with previous results seismic profiling swath bathymetry sonar have facilitated the study of the overall deformation pattern of the area which includes three distinct major structural domains facing various forelands 1 1 the outer domain is bounded southward by the present day wedge toe and towards the north by topographic slope breaks and clear changes in deformational style beneath the ionian and levantine mediterranean ridge branches the base of messinian evaporites seems to act as a major decollement level 2 2 the central or crestal domain the shallowest one shows evidence of mud diapiric and mud volcano activity and is overthrusting northward over the inner domain facing the libyan margin this area which displays spectacular mud volcano fields appears much wider and shallower 3 3 the less deformed inner domain is bounded northward by the hellenic trench system beneath its ionian inner area seismic velocities characteristic of continental crust have been recorded while within its levantine region it is made of a series of disconnected and uplifted basement blocks strabo seamounts along the matapan and pliny trenches structures which could be caused by transpressive deformation are locally observed we believe that both the north south structural arrangement and the clear west east lateral variations of the mediterranean ridge relate to its progressive collision against the libyan margin promontory this event which may have initiated 5 6 myr ago may have induced a a differentiated paleogeography of messinian evaporites later available for tectonic accretion leading to the further lateral structural variations of the outer domain and b strain partitioning between the central mediterranean ridge and the hellenic trench system

tidal oscillations in the aegean and ionian seas abstract harmonic constants are estimated by analysing tidal observations from 20 ports in the aegean and the ionian seas areas where no similar data were available so far the analysis is based on tidal records 7 years long the resulting values for the m 2 constituent are compared with the results of a hydrodynamic numerical model of the m 2 tide for the mediterranean sea the qualitative agreement between the observations and the model indicates that in spite of the complex topography of the aegean sea the major features of the tidal propagation could be retrieved through the model if better tuned

seismic velocities from the barbados ridge complex indicators of high pore fluid pressures in an accretionary complex three wide aperture 0 5 km offset seismic profiles were shot perpendicular to the strike of the barbados ridge accretionary complex at 16 12 n line 465 14 23 n line 480 and 13 20 n line 484 to image the deep structure of the accretionary complex and obtain seismic velocity data velocity analyses on full fold common depth point cdp gathers were used to provide velocity depth functions at 1 km separation along each line to map the variation in velocity with depth and distance across the accretionary complex the sediments within the complex show consolidation increasing laterally with greater age of the complex as indicated by the increase in seismic velocity and the inferred decrease in porosity the velocity at the base of the wedge along line 480 is 2 4 km s at the toe the velocity at the wedge base at 60 km from the toe where the wedge thickness has increased from 1 8 km to 5 0 km has increased to greater than 3 0 km s however the velocities within the leading margins and within undeithrust sequences in each of the three sections are low as much as 1 0 km s less than velocities found in undeformed sedimentary sequences of equivalent thickness the low velocity regions are interpreted as sediments with high porosity where porosity is inferred to be high pore fluid pressures are also inferred to exceed hydrostatic and pore fluids actually support the increased lithostatic load produced by recent thrusting and thickening of the complex the correlation between the most rapidly thickened regions and the velocity anomalies suggests that a rapid rate of loading relative to the rate of pore fluid expulsion produced these overpressured sediments velocities in the underthrust sequences where the differences between loading histories of wedge sediments and the underthrust sequences are largest are sufficiently low to produce velocity inversions low velocities also occur in regions adjacent to the complex where the pore fluid pressures may be elevated by the pressure produced in the adjacent wedge west of the wedge in the forearc basin along line 480 and near a seismically imaged mud diapir velocities at a depth of 3 5 km below the seafloor are 0 5 km s less than what is expected in a more normal sedimentary section immediately seaward of the complex the deepest undeformed sequences have a velocity anomaly of 0 5 km s velocities remain low for at least 12 km seaward of the complex but they become closer to a more normal sediment section farther from the wedge

crustal block movements from holocene shorelines rhodes island greece abstract signs of up to eight stepped holocene shorelines which have been reported in a previous study on the east coast of rhodes island have been reinvestigated in detail on the basis of a new geomorphological survey identification and petrological analysis of many new samples of exposed marine organic crusts and over 30 radiocarbon datings confirmation was obtained of the view that the island can be charactered by considering small crustal blocks up to a dozen kilometres long with each block being affected by a specific tectonic history and a general trend towards an uplift increasing from south to north two successive phases of submergence emergence have been revealed by petrogenetic sequences in many samples which give evidence of the occurrence of positive and negative vertical movements this implies possible rejuvenation effects of the later submergence phase on the apparent age of pre existing algal crusts and those have been taken into account and estimated the most likely sequence of vertical crustal movements to have occurred has been specified for each block and a time range has been ascribed to each former shoreline independent up and down movements increasing in amplitude from south to north appear in most blocks there is a recurrent periodicity varying from a few hundred to one or at most two thousand years the largest vertical displacement observed during the late holocene a sudden uplift movement of about 3 8 m in the northernmost part of the island is likely to be linked with the earthquake which destroyed the colossus in 222 b c

seismic coastal uplift and subsidence in rhodes island aegean arc evidence from an uplifted ancient harbour abstract archaeological evidence from a 2400 years old harbour currently about 3 m above sea level sheds light on an enigmatic sequence of coastal uplift and subsidence along the coasts of rhodes island close to a 4 km deep trough marking the east edge of the aegean arc the tectonics of this area are not clear because of the absence of major earthquakes in the last 80 years but are likely to be controlled by a combination of shear and compression producing strong earthquakes some associated with tsunamis and some with thrust uplifted notches the latter up to 6000 years old also show evidence of phases of subsidence our study focuses on remains of shipsheds in particular a ramp used to pull warships out of the water and keep them protected under cover during winter this ramp was constructed between approximately 250 225 bc and some decades later it was repaved after a major earthquake destroyed the town of rhodes and most probably the harbour and sheltered ships as historical evidence reveals 300 years later the harbour was to a great part abandoned because of a coastal uplift the only reasonable explanation for the ramp reconstruction was to counteract a 1 m seismic subsidence at around 220 bc or earlier several possible explanations can be proposed for the earthquake which produced seismic subsidence alternating with uplift in rhodes in a pattern of vertical motions different from that observed in crete or other convergent boundaries

convergence rate across the nepal himalaya and interseismic coupling on the main himalayan thrust implications for seismic hazard we document geodetic strain across the nepal himalaya using gps times series from 30 stations in nepal and southern tibet in addition to previously published campaign gps points and leveling data and determine the pattern of interseismic coupling on the main himalayan thrust fault mht the noise on the daily gps positions is modeled as a combination of white and colored noise in order to infer secular velocities at the stations with consistent uncertainties we then locate the pole of rotation of the indian plate in the itrf 2005 reference frame at longitude 1 34 3 31 latitude 51 4 0 3 with an angular velocity of 0 5029 0 0072 myr the pattern of coupling on the mht is computed on a fault dipping 10 to the north and whose strike roughly follows the arcuate shape of the himalaya the model indicates that the mht is locked from the surface to a distance of approximately 100 km down dip corresponding to a depth of 15 to 20 km in map view the transition zone between the locked portion of the mht and the portion which is creeping at the long term slip rate seems to be at the most a few tens of kilometers wide and coincides with the belt of midcrustal microseismicity underneath the himalaya according to a previous study based on thermokinematic modeling of thermochronological and thermobarometric data this transition seems to happen in a zone where the temperature reaches 350 c the convergence between india and south tibet proceeds at a rate of 17 8 0 5 mm yr in central and eastern nepal and 20 5 1 mm yr in western nepal the moment deficit due to locking of the mht in the interseismic period accrues at a rate of 6 6 0 4 10 19 nm yr on the mht underneath nepal for comparison the moment released by the seismicity over the past 500 years including 14 m w 7 earthquakes with moment magnitudes up to 8 5 amounts to only 0 9 10 19 nm yr indicating a large deficit of seismic slip over that period or very infrequent large slow slip events no large slow slip event has been observed however over the 20 years covered by geodetic measurements in the nepal himalaya we discuss the magnitude and return period of m 8 earthquakes required to balance the long term slip budget on the mht

water flow in the barbados accretionary complex we present a simple analytic kinematic model of the barbados accretionary complex assuming a porosity depth law and deformation by pure vertical shear the model is applied to two sections a northern one with a 900 m thick basin sedimentary column near 16 n and a southern one with a 4 5 km thick one to the south this simple model is compatible with growth of the barbados accretionary complex since 50 ma assuming a constant subduction rate and a constant basin sedimentary column equal to the present one this conclusion is not affected by reasonable changes in the porosity depth law it suggests that the totality of the entering sedimentary column is either accreted or subcreted to the wedge the accretion velocity decreases dramatically with age and its variation should be taken into account in any quantitative model the average strain rates show remarkably different distributions between the two sections the thinner wedge having a much higher rate in a narrow area at the toe we then use the model to compute the sediment grains flow the fluid flow and their thermal effects these effects are small and do not exceed 5 of the heat flow in the absence of other internal flows in contrast the thermal effect of the burial of the slab can result in a lowering of the surface heat flow by as much as 40 the temperature at the base of the wedge on its arc side is close to 300 c on the southern section and half that amount on the northern one this high temperature could account for the absence of large earthquakes to the south and their presence to the north the amount of water discharged if collected by faults over the whole toe area is unable to account for some of the manifestations observed over the toe or seaward of the toe in the barbados area we suggest two possible other sources one for the southern section is the orinoco fan area the other for the northern section might be seismic pumping at the limit of the seismogenic zone along the backthrusts between the accretionary wedge and the forearc basin

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

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

modeling of fluid flow and pore pressure at the toe of oregon and barbados accretionary wedges fluid venting was recently found on the central oregon accretionary wedge and evidence of fluid flow along the decollement were obtained in the barbados wedge the chemistry of hydrocarbons contained in the migrating fluids is different in these two areas and indicates that the main source is deep for the barbados decollement and shallow for the oregon vents we apply a finite element model with imposed thrusting kinematics and nonlinearities in the compaction equation to the toe of both wedges no deep fluid source is included thus the main source is the footwall just below the frontal thrust the model indicates the following 1 pore pressure build up would be essentially controlled by kn the equivalent permeability in the direction normal to the strata in spite of very different sediment lithologies kn is of the order of 10 17 m2 for both oregon turbidites horath 1989 and barbados muds taylor and leonard 1990 and no high pore pressures can be obtained inside the offscraped sediments 2 permeability anisotropy greatly modifies fluid flow paths a fault with a permeability anisotropy of 103 would channel fluids efficiently but leave the footwall pressure almost unchanged a stratigraphic permeability anisotropy of 102 as documented for the oregon turbidites would redirect the flow of pressurized fluids in the footwall along strata into the trench if clogging of the frontal thrust occured fluids expelled from the footwall would move across the frontal thrust migrate along permeable strata in the hanging wall and then be vented near the top of the eroded anticline as observed in oregon 3 comparison of published estimates from data of fluid explusion fluxes with the modeling results suggests that a deeper and larger fluid source is needed at the barbados site but is not required for the oregon site

postseismic afterslip 30 years after the 1978 tabas e golshan iran earthquake observations and implications for the geological evolution of thrust belts this paper presents insar observations of postseismic afterslip occurring up to 30 yr after the mw7 3 1978 tabas e golshan thrust faulting earthquake in eastern iran comparison of the surface motion from 1996 to 1999 with that from 2003 to 2010 along with information provided by the quaternary averaged slip rates of faults in the region suggests that the imaged slip is transient and decaying through time models of the surface deformation field imply slip on faults dipping at 55 10 reaching from the surface to depths of 4 5 km and slipping at 5 1 mm yr 1 these faults outcrop on the margins of low anticlinal hills composed of actively uplifting neogene deposits when compared with the previously studied main shock focal parameters slip on a plane dipping at 16 5 with a centroid depth of 9 km and the aftershock distribution a band at 6 14 km the insar results imply postseismic slip on a high angle thrust ramp connecting the surface anticlines to the coseismic low angle fault plane at depth in one location both a thrust ramp and also a backthrust are postseismically active the insar observations demonstrate the role of postseismic afterslip in the growth of these commonly observed thrust belt geometries and highlight that deformation throughout the seismic cycle can contribute to the geological evolution of regions of active faultin

sea level change along the french mediterranean coast for the past 30 000 years abstract observational evidence for sea level change along the french mediterranean coast has been examined and compared with glacio hydro isostatic models to predict the spatial and temporal patterns of change for about the past 30 000 14c years these predictions are pertinent to discussions of changing ocean volumes during this interval the tectonic stability or otherwise of the coastal areas mantle rheology and the timing of possible human occupation of the now submerged coastal plain and caves such as cosquer cave near marseille the principal results from the analysis are i sea levels along this section of the coast have risen continually since the time of the last glacial maximum lgm and at no time during the holocene has the mean sea level been higher than that of today ii the coast has been tectonically stable between marseille and nice as well as further to the west in roussillon western corsica may have experienced a slow tectonic uplift of between 0 15 0 3 mm year for the past 3000 years but northernmost corsica appears to have been stable during this same interval iii during the lgm sea levels along the coast and immediate off shore areas stood at between 105 115 m below present level the range reflecting the importance of the isostatic contributions during oxygen isotope stage 3 sea levels do not appear to have risen locally above about 60 m iv the rebound parameters describing the mantle rheology and ice sheets required to match the limited observational evidence are consistent with the results of similar analyses carried out for other parts of europe because of its distance from the former northern ice sheets the isostatic factors are particularly sensitive to the value of the lower mantle viscosity v the model predictions for sea level change at the cosquer cave site and for its immediate environments indicate that the cave was last readily accessible before about 10 700 500 14c years about 12 500 500 cal years bp and that the cave entrance was completely flooded by 9000 200 radiocarbon years bp between about 9800 and 10 300 calibrated years bp the cave was above sea level throughout the oxygen isotope stage 3

earthquake source parameters along the hellenic subduction zone and numerical simulations of historical tsunamis in the eastern mediterranean abstract we studied source mechanism parameters and slip distributions of earthquakes with m w 5 0 occurred during 2000 2008 along the hellenic subduction zone by using teleseismic p and sh waveform inversion methods in addition the major and well known earthquake induced eastern mediterranean tsunamis e g 365 1222 1303 1481 1494 1822 and 1948 were numerically simulated and several hypothetical tsunami scenarios were proposed to demonstrate the characteristics of tsunami waves propagations and effects of coastal topography the analogy of current plate boundaries earthquake source mechanisms various earthquake moment tensor catalogues and several empirical self similarity equations valid for global or local scales were used to assume conceivable source parameters which constitute the initial and boundary conditions in simulations teleseismic inversion results showed that earthquakes along the hellenic subduction zone can be classified into three major categories 1 focal mechanisms of the earthquakes exhibiting e w extension within the overriding aegean plate 2 earthquakes related to the african aegean convergence and 3 focal mechanisms of earthquakes lying within the subducting african plate normal faulting mechanisms with left lateral strike slip components were observed at the eastern part of the hellenic subduction zone and we suggest that they were probably concerned with the overriding aegean plate however earthquakes involved in the convergence between the aegean and the eastern mediterranean lithospheres indicated thrust faulting mechanisms with strike slip components and they had shallow focal depths h

the 1956 greek tsunami recorded at yafo israel and its numerical modeling floating type tidal gauge installed in the port of yafo israel the tsunami was triggered by an earthquake in the aegean sea on 9 july 1956 this paper presents a retrieval of tsunami waves from the record at the first stage of the study an attempt had been undertaken to reproduce the 1956 tsunami assuming a coseismic nature of its generation source although these simulations resulted in tsunami waves with their amplitude close to that obtained from the record measured at yafo they did not contain significant spectral energy components with periods of 15 min as appear in the spectra of 1956 tide gauge records when landslide movement triggered by the main shock and or by the largest aftershock is suggested as a source of these tsunami waves the spectra of the resulted marigram obtained in the proximity to yafo contain harmonics with frequencies very close to those measured this corroborates the landslide nature of the tsunamigenic source responsible for generation of higher frequency relative to the tidal waves energy components the peak periods determined via spectral analysis of the recent tide gauge records 1 year and longer in the absence of tsunami events vary from 50 to 60 min similar periods have been revealed in a special numerical study dealing with longwave propagation toward the coast of israel thus confirming that their origin is related to continental shelf resonance these resonance periods differ significantly from those found for the 1956 tsunami

geodetic evidence for low coupling on the hellenic subduction plate interface we develop a block model for the aegean and surrounding areas constrained by global positioning system gps in order to investigate the degree of coupling on the hellenic subduction interface i e the fraction of the motion across the plate boundary accommodated by elastic strain accumulation we use previously published models and seismicity to define the geometry of the interface separating the down going nubian slab from the overriding aegean this model provides a good fit to the gps observations for the 200 000 km2 aegean block the wrms of the residual velocities is 1 4 mm yr for 80 gps velocity estimates approximately the 95 level of the gps velocity uncertainties we investigate the degree of coupling on the seismically active plate interface the hellenic trench splay fault believed to be the source of the 365 ad great crete earthquake and tsunami and the kephalonia transform fault by comparing the modeled gps residual velocity field for a range of coupling values the gps observations are almost insensitive to coupling on the kephalonia transform fault because of the vertical dip of the fault that creates interseismic deformation only close to the fault where few gps sites exist the absence of resolvable shortening of the leading edge of the aegean plate precludes coupling of more than 0 2 20 of the full nubia aegean convergence rate on the modeled plate interface because of the shallow dip of the plate interface and trench splay fault and high rate of convergence if these boundaries were fully coupled high elastic strain rates would be expected to extend well into the overriding aegean plate based on our preferred value for the degree of coupling 0 1 and assuming characteristic earthquake behavior we estimate a recurrence time for great earthquakes with slip similar to that for the 365 crete event of 5700 8300 yr consistent with the absence of subsequent great earthquakes on this segment of the subduction zone

the 2017 july 20 mw 6 6 bodrum kos earthquake illuminates active faulting in the gulf of gokova sw turkey

hydrogeochemistry of the northern barbados accretionary complex transect ocean drilling project leg 110 detailed studies of the major element geochemistry oxygen and hydrogen isotope ratios of pore fluids and the 87sr 86sr ratio of dissolved strontium have made it possible to unravel physical and chemical processes that affect the pore fluid chemistry in a transect of drill holes across the northern barbados accretionary complex these processes include 1 alteration of volcanic ash buried in the pleistocene pliocene sediment column 2 alteration of underlying basalts of layer 2 of the oceanic crust 3 movement of fluids from deep in the accretionary complex along fault zones particularly the decollement and minor permeable layers these fluids from deeper in the complex are characterized by low chloride concentrations and increased 18o h2o values presumably as a result of dehydration of smectite interlayers and 4 mixing processes involving the migrating fluids cause incongruities in the geochemical anomalies of these fluids

tsunamis observed in greece and the surrounding area from antiquity up to the present times abstract a new and improved catalogue of tsunamis observed in greece and the surrounding area from antiquity up to the present time is presented reliable information derived from previous catalogues as well as original historical information which has not been previously taken into account has been used as data source as far as the associated earthquakes are concerned some recent and reliable seismological catalogues have been used as data sources the main cause of the generation of tsunamis is the shallow seismic activity that occurs along the hellenic arc as well as in the internal seismic zone of the aegean area the statistics for tsunamis indicate that the tsunami hazard is low considering the area in question as a whole ten distinct coastal regions in which this hazard can be suggested as medium or high have been defined

coastal uplift earthquakes and active faulting of rhodes island aegean arc modeling based on geodetic inversion the geodetic inversion technique was used to model the fault pattern responsible for the uplifted holocene notches along the ne rhodes island coast se edge of the hellenic aegean arc input in the modeling was the elevation of uplifted notches up to 6000 yr old which are interpreted to reflect remains of fossil shorelines to testify to a series of earthquakes producing both uplift and subsidence i e to elastic dislocations and to correspond to geodetic data senso lato these shorelines up to 3 8 m high were probably originally continuous along the whole of the 75 km long se rhodes coast possibly locally disturbed by minor normal faults and reflect the last phases of the uplift and tilting of the island as a rather rigid block since late pliocene their radiocarbon dating was further refined from archeological data testifying to an about 1 m subsidence associated with the 227 bc earthquake followed by 3 m seismic uplift inversion constrained by the hypothesis of a compressional fault offshore rhodes was based on standard uniform slip elastic dislocation analysis it proved to depend only weakly even on extreme glacio isostatic corrections and indicated that coastal uplift is dominated by a main compressional fault zone offshore sub parallel to the island coast with normal faults inland reflecting thin skin tectonics this fault pattern similar to that of western crete is confirmed by seismic reflection profiles indicating a major reverse close to the modeled fault and can explain 1 the occurrence of strong m 7 5 historical earthquakes producing tsunamis and destruction on an east mediterranean scale 2 the alternation of uplift and subsidence as a result of fault shift inside the same fault zone and 3 the long term uplift of the island as a rather conjugate effect of the formation of an about 4 5 km deep 5 myr old marine basin se of rhodes bounded to the nw by the modeled fault zone the seismic risk of rhodes higher in its ne part of the island and than what was previously believed is associated with strong m 7 5 earthquakes producing widespread destruction tsunamis coastal uplift and coastal subsidence

pliocene quaternary tectonic evolution of the gulf of gokova southwest turkey abstract evolution of the east west trending gokova graben structure is related to the north south extension of the aegean segment of the aegean anatolian microplate the pliocene quaternary successions surrounding the onland portion of the gokova graben as well as coeval successions within the marine portion of the graben are cut by at least three families of faults that strike northwest southeast east west and east northeast west southwest these orientations are inconsistent with a simple north south extensional regime interpretation of seismic reflection profiles multibeam bathymetry and gps vectors indicates that the gokova graben developed as a lazy s shaped graben in the back arc setting north of the hellenic arc a counterclockwise rotation of the aegean segment of the aegean anatolian microplate is the suggested mechanism for this geometry as subduction zone rolled back occurred during the pliocene quaternary the gulf of gokova is the youngest of a series of basins that developed within this large back arc system including the nisyros karpathos and kamilonisi basins collectively named to as the gokova nisyros karpathos graben it is proposed that this graben experienced a scissor like opening initiating from the west during the pliocene and progressing eastward during the quaternary faults that are seemingly un correlated onland and in the marine areas become remarkably aligned when the marmaris rhodes block is progressively rotated by 6 counterclockwise relative to the mugla block using a pole position located within the gulf of gokova the scissor like opening of the westernmost regions of the gokova graben likely occurred during the late pliocene whereas the central and eastern portions of the graben developed during the early middle pleistocene and late pleistocene holocene respectively the onset of the opening of the westernmost segment of the gokova nisyros karpathos graben occurred at a time earlier than the late pliocene

historical and pre historical tsunamis in the mediterranean and its connected seas geological signatures generation mechanisms and coastal impacts abstract the origin of tsunamis in the mediterranean region and its connected seas including the marmara sea the black sea and the sw iberian margin in the ne atlantic ocean is reviewed within the geological and seismotectonic settings of the region a variety of historical documentary sources combined with evidence from onshore and offshore geological signatures geomorphological imprints observations from selected coastal archeological sites as well as instrumental records eyewitnesses accounts and pictorial material clearly indicate that tsunami sources both seismic and non seismic e g volcanism landslides can be found in all the seas of the region with a variable tsunamigenic potential local regional and basin wide tsunamis have been documented an improved map of 22 main tsunamigenic zones and their relative potential for tsunami generation is presented from west to east the most important tsunamigenic zones are situated offshore sw iberia in the north algerian margin in the tyrrhenian calabria and messina straits in the western and eastern segments of the hellenic arc in the corinth gulf of central greece in the levantine sea offshore the dead sea transform fault and in the eastern side of the marmara sea important historical examples including destructive tsunamis associated with large earthquakes are presented the mean recurrence of strong tsunamis in the several basins varies greatly but the highest event frequency 1 96 years is observed in the east mediterranean basin for most of the historical events it is still unclear which was the causative seismic source and if the tsunami was caused by co seismic slip by earthquake triggered submarine landslides or by a combination of both mechanisms in pre historical times submarine volcanic eruptions i e caldera collapse massive pyroclastic flows volcanogenic landslides and large submarine landslides caused important tsunamis although little is known about their source mechanisms we conclude that further investigation of the tsunami generation mechanisms is of primary importance in the mediterranean region inputs from tsunami numerical modeling as well as from empirical discrimination criteria for characterizing tsunami sources have been proved particularly effective for recent well documented aseismic landslide tsunamis e g 1963 corinth gulf 1979 cote d azur 1999 izmit bay 2002 stromboli volcano since the tsunami generation mechanisms are controlled by a variety of factors and given that the knowledge of past tsunami activity is the cornerstone for undertaking tsunami risk mitigation action future interdisciplinary research efforts on past tsunamis are needed

jellies under ice rov observations from the arctic 2005 hidden ocean expedition abstract in order to provide a baseline understanding of gelatinous zooplankton biodiversity and distribution in the rapidly changing arctic ocean 12 stations were sampled across the canada basin northwind ridge and chukchi plateau with detailed deep water rov observations and multinet tows down to 3000 m the complex multi origin water layers of the arctic ocean provided the backdrop for examining the vertical and horizontal distributions of the poorly understood meso and bathypelagic gelatinous taxa over 50 different gelatinous taxa were observed across the stations with cnidarians being the most common group medusae accounted for 60 of all observations siphonophores for 24 larvaceans for 10 ctenophores for 5 and numerous interesting and rarer taxa constituted the remaining 1 of observations several new species were found and many major range extensions were observed both the vertical and horizontal distribution of species appear to be linked to water mass characteristics as well as bottom topography and geographic location within the study area shallow slope and ridge areas around the canada basin and chukchi plateau appear to harbor substantially lower gelatinous zooplankton biomass and diversity than the deeper locations shallow stations not only show reduced abundance but also different relative abundance of the major taxa where the shallow water stations are dominated by large numbers of siphonophores and ctenophores the deep stations are dominated by medusae taxonomic issues and ecological observations of several important species are discussed aided by the live collection of many undamaged and fragile species

the october 28 2012 mw 7 8 haida gwaii underthrusting earthquake and tsunami slip partitioning along the queen charlotte fault transpressional plate boundary the pacific north american plate boundary is undergoing predominantly right lateral strike slip motion along the queen charlotte and fairweather transform faults the queen charlotte fault qcf hosted the largest historical earthquake in canada the 1949 m s 8 1 strike slip earthquake which ruptured from offshore northern haida gwaii several hundred kilometers northwestward on january 5 2013 an m w 7 5 strike slip faulting event occurred near the northern end of the 1949 rupture zone along central and southern haida gwaii the relative plate motion has 20 oblique convergence across the left stepping plate boundary there had been uncertainty in how the compressional component of plate motion is accommodated the october 28 2012 m w 7 8 haida gwaii earthquake involved slightly 20 oblique thrust faulting on a shallow 18 5 northeast dipping fault plane with strike 320 parallel to the qcf consistent with prior inferences of pacific plate underthrusting beneath haida gwaii the rupture extended to shallow depth offshore of moresby island beneath a 25 30 km wide terrace of sediments that has accumulated in a wedge seaward of the qcf the shallow thrusting caused seafloor uplift that generated substantial localized tsunami run up and a modest far field tsunami that spread across the northern pacific prompting a tsunami warning beach closure and coastal evacuation in hawaii although ultimately tide gauges showed less than 0 8 m of water level increase the mainshock rupture appears to have spread with a 2 3 km s rupture velocity over a length of 150 km with slip averaging 3 3 m concentrated beneath the sedimentary wedge the event was followed by a substantial aftershock sequence in which almost all of the larger events involve distributed intraplate normal faulting extending 50 km oceanward from the qcf the highly oblique slip partitioning in southern haida gwaii is distinctive in that the local plate boundary parallel motion on the qcf may be accommodated either by infrequent large strike slip ruptures or by aseismic creep as seems to be the case for deeper oblique relative plate motion beneath haida gwaii while the sedimentary terrace accumulates plate boundary perpendicular compressional strain that releases in almost pure thrust faulting earthquakes seaward of the qcf

the 8 5 magnitude ad365 earthquake in crete coastal uplift topography changes archaeological and historical signature abstract an up to 9 m uplift of western crete a cluster of coastal uplifts in the east mediterranean radiocarbon dated approximately 1500 bp as well as historical and archaeological data are evidence for major although poorly documented seismic destruction on a nearly mediterranean scale in the 4th to 5th c ad including the destruction of the nile delta in egypt by a tsunami in ad365 these data represent parts of a puzzle for historians archaeologists geologists and seismologists detailed analysis of geological historical and archaeological data including precise numismatic evidence permits recognition of a major earthquake in crete responsible for coastal uplift at ad365 elastic dislocation analysis of coastal uplift data reveals that this earthquake was associated with a reverse fault offshore of southwestern crete that its minimum magnitude was 8 5 and that this model is consistent with the available seismological and large scale tectonic data despite its magnitude this earthquake cannot have produced the necessary short period high energy waves which are necessary to explain the seismic damage which occurred circa ad365 in a very broad region from sicily to cyprus and libya hence the ad365 earthquake sequence included at least two other major events with epicentres close to cyprus and sicily although significant changes in the coastal morphology widespread destruction and a high human death toll occurred the ad365 crete earthquake was not responsible for any major cultural change it occurred during the transition from the roman to the christian period characterized by vast luxurious villas and modest dwellings on crete respectively

late holocene uplift of rhodes greece evidence for a large tsunamigenic earthquake and the implications for the tectonics of the eastern hellenic trench system several large earthquakes in the hellenic subduction zone have been documented in historical records from around the eastern mediterranean but the relative seismic quiescence of the region over the period of instrumental observation means that the exact locations of these earthquakes and their tectonic significance are not known we present ams radiocarbon dates from uplifted late holocene palaeoshorelines from the island of rhodes showing that uplift is most consistent with a single large mw 7 7 reverse faulting earthquake between about 2000 bc and 200 bc analysis of the uplift treating the earthquake as a dislocation in an elastic half space shows a predominantly reverse faulting event with a slip vector oblique to the direction of convergence between rhodes and nubia we suggest that the fault responsible for the uplift dips at an angle of 30 60 above the more gently dipping oblique subduction interface the highly oblique convergence across the eastern hellenic plate boundary zone appears to be partitioned into reverse slip on faults that strike parallel to the boundary and strike parallel or oblique slip on the subduction interface hydrodynamical simulation of tsunami propagation from a range of tectonically plausible sources suggests that earthquakes on the fault uplifting rhodes represent a significant tsunami hazard for rhodes and sw turkey and also possibly for cyprus and the nile delta

a tsunami warning system based on offshore bottom pressure gauges and data assimilation for crete island in the eastern mediterranean basin the eastern mediterranean basin emb is under the threat of tsunami events triggered by various causes including earthquakes and landslides we propose a deployment of offshore bottom pressure gau

seismicity of the hellenic subduction zone in the area of western and central crete observed by temporary local seismic networks temporary local seismic networks were installed in western crete in central crete and on the island gavdos south of western crete respectively in order to image shallow seismically active zones of the hellenic subduction zone more than 4000 events in the magnitude range between 0 5 and 4 8 were detected and localized the resulting three dimensional hypocenter distribution allows the localization of seismically active zones in the area of western and central crete from the mediterranean ridge to the cretan sea furthermore a three dimensional structural model of the studied region was compiled based on results of wide angle seismics surface wave analysis and receiver function studies the comparison of the hypocenter distribution and the structure has allowed intraplate and interplate seismicity to be distinguished high interplate seismicity along the interface between the subducting african lithosphere and the aegean lithosphere was found south of western crete where the interface is located at about 20 to 40 km depth an offset between the southern border of the aegean lithosphere and the southern border of active interplate seismicity is observed in the area of crete the offset varies laterally along the hellenic arc between about 50 and 70 km a southwards dipping zone of high seismicity within the aegean lithosphere is found south of central crete in the region of the ptolemy trench it reaches from the interface between the plates at about 30 km depth towards the surface in comparison the aegean lithosphere south of western crete is seismically much less active including the region of the ionian trench intraplate seismicity within the aegean plate beneath crete and north of crete is confined to the upper about 20 km between 20 and 40 km depth beneath crete the aegean lithosphere appears to be seismically inactive in western crete the southern and western borders of this aseismic zone correlate strongly with the coastline of crete

the 1956 earthquake and tsunami in amorgos greece summary we conduct a comprehensive study of the amorgos greece earthquake and tsunami of 1956 july 09 the largest such event in the aegean sea in the 20th century systematic relocation of the main shock and 34 associated events defines a rupture area measuring 75 40 km the use of the preliminary determination of focal mechanism algorithm resolves the longstanding controversy about the focal geometry of the event yielding a normal faulting mechanism along a plane dipping to the southeast which expresses extensional tectonics in the back arc behind the hellenic subduction zone the seismic moment of 3 9 10 27 dyn cm is the largest measured in the past 100 yr in the mediterranean basin a quantitative database of 68 values of tsunami run up was built through the systematic interview over the past 5 yr of elderly eyewitness residents of 16 aegean islands and the turkish coast of asia minor it confirms values of up to 20 m on the southern coast of amorgos 10 m on astypalaia and up to 14 m on the western coast of folegandros 80 km to the west of the epicentre these values largely in excess of the inferred seismic slip at the source and their concentration along isolated segments of fault are incompatible with the generation of the tsunami by the seismic dislocation and require an ancillary source in the form of a series of landslides triggered by the earthquake and or its main aftershocks a model confirmed by hydrodynamic simulations using both the dislocation source and models of landslide sources

holocene emergence in euboea island greece abstract detailed mapping along the northwestern coastline of euboea has provided new evidence of colonization by lithophaga lithophaga l reaching about 3 8 m above the present biological msl such marine biological marks together with morphological notches correspond to the occurrence of two sequences of holocene vertical displacements higher than those reported by previous studies on the central part of the southern coast and along the northern coast of the island a well developed emerged notch is found at 1 7 0 1 m above present mean sea level whereas the uppermost part of the lithophagid holes suggest a former emerged shoreline at least at 3 8 0 1 m radiocarbon ams dating of lithophaga shells found in their burrows showed that the lower uplifted shoreline corresponds to a tectonic event probably coseismic apparently dated at 2200 a bp while the higher shoreline corresponds to an older relative sea level transgression possibly of tectonic origin apparently dated about 5570 a bp the apparent radiocarbon age of lithophagid shells can be about 350 to 400 years older than the uplift event that exposed them due to incorporation of host rock carbon nevertheless the two new paleoshorelines provide evidence that repeated uplift movements greater than those reported by previous authors occurred during the late holocene uplifting the western part of the island

the canada basin 1989 1995 upstream events and far field effects of the barents sea 1 the effects of upstream events on southern canada basin waters were examined using physical and geochemical data collected at one location between 1989 and 1995 these events included atlantic layer warming relocation of the atlantic pacific water mass boundary and increased ventilation of boundary current waters early signals of change in the canada basin first appeared in 1993 along the continental margin and by 1995 were evident in the basin interior and farther downstream differences in physical and geochemical properties nutrients oxygen 129i and cfcs were observed between 150 and 1600 m of the water column by 1995 the boundary between pacific and atlantic origin water was shallower and atlantic origin water occupied more of the canada basin water column atlantic origin lower halocline water was colder and more ventilated fram strait branch water was colder fresher and more ventilated and barents sea branch water was warmer fresher more ventilated and occupied a larger volume of the water column than in previous years water mass analysis showed that the composition of atlantic origin water in the canada basin in 1995 included 20 more water from the barents sea two related events upstream appear to be the source of this change an atmospheric regime shift in 1989 that increased cyclonic circulation a transition unprecedented within the latter half of the 20th century in magnitude geographic reach and apparent oceanographic impacts and a large volume of dense water flowed from the barents sea to the arctic ocean between 1988 and 1989 these two phenomena illustrate the close relationship between atmospheric and oceanic events whose combined influence was evident 6 years later and 5100 km downstream in the canada basin at depths 1000 m

hydrogeology and mechanics of subduction zone forearcs fluid flow and pore pressure at subduction zones fluid flow pore pressure and tectonic processes are tightly interconnected excess pore pressure is driven by tectonic loading and fluids released by mineral dehydration and it has profound effects on fault and earthquake mechanics through its control on effective stress the egress of these overpressured fluids which is in part governed by the presence of permeable fault zones is a primary mechanism of volatile and solute transport to the oceans recent field measurements new constraints gained from laboratory studies and numerical modeling efforts have led to a greatly improved understanding of these coupled processes here we summarize the current state of knowledge of fluid flow and pore pressure in subduction forearcs and focus on recent advances that have quantified permeability architecture fluxes the nature and timing of transience and pressure distribution thus providing new insights into the connections between fluid metamorphic mechanical and fault slip proc

thin and thinner sea ice mass balance measurements during sheba 1 as part of a large interdisciplinary study of the surface heat budget of the arctic ocean sheba we installed more than 135 ice thickness gauges to determine the sea ice mass balance while installing these gauges during the fall of 1997 we found that much of the multiyear ice cover was only 1 m thick considerably thinner than expected over the course of the yearlong field experiment we monitored the mass balance for a wide variety of ice types including first year ice ponded ice unponded ice multiyear ice hummocks new ridges and old ridges initial ice thicknesses for these sites ranged from 0 3 to 8 m and snow depths varied from a few centimeters to more than a meter however for all of their differences and variety these thickness gauges sites shared a common trait at every site there was a net thinning of the ice during the sheba year the thin ice found in october 1997 was even thinner in october 1998 the annual cycle of ice thickness was also similar at all sites there was a steady increase in thickness through the winter that gradually tapered off in the spring this was followed by a steep drop off in thickness during summer melt and another tapering in late summer and early fall as freeze up began maximum surface melting was in july while bottom ablation peaked in august combining results from the sites we found an average winter growth of 0 51 m and a summer melt of 1 26 m which consisted of 0 64 m of surface melt and 0 62 m of bottom melt there was a weak trend for thicker ice to have less winter growth and greater net loss for the year however ice growth was also impacted by the snow depth considerable variability was observed between sites in both accretion and ablation the total accretion during the 9 month growth season ranged from zero for thick ridged ice to more than a meter for young ice ponds tended to have a large amount of surface melting while ridges had considerable bottom ablation

a statistical space time magnitude analysis on the aftershocks occurrence of the july 21th 2017 mw 6 5 bodrum kos turkey earthquake abstract in this study a detailed space time magnitude assessment on the aftershock sequence of july 21th 2017 mw 6 5 bodrum kos earthquake turkey is carried out by focusing on the analyses of aftershock parameters b value p value dc value and mamax b value is estimated as 0 90 0 05 with a completeness magnitude mc 1 6 and this relatively small b value may be resulted from the abundance of aftershocks with magnitude ml 4 0 however it is well represented by the gutenberg richter law with a typically b 1 0 p value is estimated as 1 04 0 02 with a c value 0 224 0 039 and is well characterized nearly close to the global p 1 0 this relatively high p value may be a result of the relative fast decay rate of the aftershock activity dc value is calculated as 1 74 0 09 and it means that aftershocks are homogeneously distributed temporal distribution of b value shows that small b values may be due to a stepwise increase in effective stress before the occurrence of larger aftershocks regional changes range from 0 5 to 1 2 in b value from 0 4 to 1 3 in p value and from 3 0 to 5 2 in mamax the smallest b values are found in and around mainshock including karaada bodrum akyarlar and turgutreis and these regions have high stress as well as coseismic deformation the largest p values are found in and around the mainshock epicenter including karaada and it is interpreted that this situation may be caused by coseismic deformation mamax values larger than 4 4 are observed in and around mainshock epicenter including bodrum and akyarlar and there is a clear correlation between spatial variations of b values and mamax these results show that stress changes and coseismic deformation seem highly effective on b and p value variations therefore a special interest needs to be given to these anomaly regions since aftershock hazard is highly associated with these parameters and may be developed considering their space time magnitude distribution

palaeotsunamis and tsunami hazards in the eastern mediterranean the dominant uncertainties in assessing tsunami hazard in the eastern mediterranean are attached to the location of the sources reliable historical reports exist for five tsunamis associated with earthquakes at the hellenic plate boundary including two that caused widespread devastation because most of the relative motion across this boundary is aseismic however the modern record of seismicity provides little or no information about the faults that are likely to generate such earthquakes independent geological and geophysical observations of two large historical to prehistorical earthquakes in crete and rhodes lead to a coherent framework in which large to great earthquakes occurred not on the subduction boundary but on reverse faults within the overlying crust we apply this framework to the less complete evidence from the remainder of the hellenic plate boundary zone identifying candidate sources for future tsunamigenic earthquakes each such source poses a significant hazard to the north african coast of the eastern mediterranean because modern rates of seismicity are irrelevant to slip on the tsunamigenic faults and because historical and geological data are too sparse there is no reliable basis for a probabilistic assessment of this hazard and a precautionary approach seems advisable

depth of seismic coupling along subduction zones underthrusting at subduction zones can cause large earthquakes at shallow depths but it is always accommodated by aseismic deformation below a certain depth the maximum depth of the seismically coupled zone or seismogenic zone is a transition from unstable to stable sliding along the plate interface we have determined the depth of this stability transition for the circurn pacific subduction zones of honshu kuriles kamchatka aleutians alaska mexico and chile these subduction zones have experienced great interplate earthquakes and the aftershock regions are well located depth estimates of interplate events that are located at the downdip edge of the aftershock regions are used to determine the maximum depth of seismic coupling for an average p wave velocity of 6 7 km s 1 above the plate interface we find that for most subduction zones the stability transition occurs at 40 5 km depth there are however several exceptions at the hokkaido trench junction where the japan trench and the kurile trench intersect seismic coupling is deep and extends down to 52 55 km deep coupling was also found in the coquimbo region in central chile the mexico subduction zone has shallow coupling the transition occurs at 20 30 km depth previous studies of micro earthquakes in honshu hokkaido the aleutians and alaska show that earthquakes within the upper plate extend no deeper than the downdip edge of the coupled zone that we find given our measurements of seismic coupling depth we then explore the mechanism that may determine coupling depth the concept of critical temperature has been used to explain the depth of seismic coupling in other tectonic environments thus we first test whether a critical temperature can explain our results temperatures at the plate interface are dependent on many variables but two that are poorly determined are shear stress and radiogenic heat generation shear stress has been constrained by inversion of heat flow data assuming a crustal radiogenic heat production rate of 3 1 exp z 8 5 wm 3 and a constant coefficient of friction we find two critical temperatures of about 400 c and 550 c the lower critical temperature may be characteristic of regions with a relatively thick continental crust and the higher temperature of regions with a relatively thin continental crust on the other hand one single critical temperature of about 250 c can explain the coupling depths if shear stresses are constant with depth

imaging and sampling beneath free drifting icebergs with a remotely operated vehicle abstract a commercially available small less than 100 kg remotely operated vehicle rov was modified to image and sample the marine ecosystem surrounding free drifting icebergs east of the antarctic peninsula during three field expeditions in 2005 2008 and 2009 modifications included fitting the vehicle with an accessory tool sled additional thrusters flotation and significant changes to internal wiring to support a wide array of sensors and samplers the rov was re configured aboard the r v nathaniel b palmer to perform either general exploration and biological sampling bio dives or water sampling chemistry dives in situ sensors and a suction sampler were used for bio dives while a suction pump and hose were fastened along the full length of the rov tether to enable continuous water sampling adjacent to each iceberg during chemistry dives details of the rov system are presented along with a discussion of the 18 dives that explored the sides and bottoms of six different icebergs during the 2009 field expedition

trench parallel fluid flow in subduction zones resulting from temperature differences differences in the thermal state of subducting crust along the trench of a subduction zone cause differences in subduction zone temperature that persist to tens of kilometers down dip of the trench the resulting differences in fluid viscosity permeability and hydraulic conductivity can lead to trench parallel variations in fluid pressure on the plate boundary fault temperature differences in locations with low decollement temperature 75 c at the trench result in large differences in fluid viscosity and fluid flow from the cold to the hot side of the system margins characterized by high decollement temperature at the trench are probably dominated by temperature controlled differences in intrinsic permeability resulting in fluid flow from the hot to the cold side of the system margins with large trench parallel temperature differences support considerable trench parallel fluid flow and the effect is accentuated for cases where compaction driven dewatering is concentrated near the trench type locations for along strike hydrologic differences include margins with subducting crust with differences in plate age along the trench or patchy hydrothermal circulation in such cases the three dimensional pattern of subduction zone fluid flow should be considered when inferring the location of the source of fluids sampled from boreholes or seeps additionally trench parallel differences in fluid pressure control effective stress on the plate boundary fault reduced effective stress on the plate boundary on the low hydraulic conductivity side of a subduction zone reduces the effective friction coefficient which both reduces frictional heating and may delay the onset of frictional instability

late quaternary sea level change sedimentation and neotectonics of the gulf of gokova southeastern aegean sea abstract the sedimentary and tectonic late quaternary evolution of the gulf of gokova located at the southwest anatolia southeastern aegean sea region has been interpreted from 800 line km of 3 5 khz and single channel airgun seismic reflection profiles the older part of the gokova basin is formed by mainly e w trending faults and filled by the latest miocene pliocene quaternary hemipelagic sediments with thickness up to 2 5 km the lycian nappes which primarily cover extreme southwestern anatolia represent the basement rocks for the gokova region younger active faulting so called gokova transfer fault gtf which has not been previously discussed in the literature trends ne in the central part of the gulf of gokova basin and records sinistral strike slip motion broadly parallel to the convergence direction of the aegean anatolian and african plates the continental shelf of the northeastern gulf of gokova is mostly formed by numerous superimposed deltaic successions depositional sequences separated by major erosional unconformities during times of lowered sea level associated with late quaternary glaciations deltas prograded more than 40 km seaward from their present positions foreset progradation terminated with the rise of sea level in interglacial and post glacial times and deltas were relocated far inland these major transgressions resulted in unconformities that are correlated with the beginning of oxygen isotope stages 9 7 5 and 1 and provide chronostratigraphic markers for a detailed analysis of sedimentation patterns in the late quaternary all seismic lines show that the topset to foreset transition of the youngest pleistocene delta system developed around 145 150 ms below present sea level thus the maximum pleistocene sea level lowering 18 000 years bp was about 110 m the positions of maximum regression for isotopic stages 6 8 and 10 were found as 160 190 and 215 m below present sea level respectively paleo shoreline positions during isotopic stages 2 6 and 8 suggest an overall gradual subsidence of gokova basin during the last 0 5 ma in the southeastern aegean sea the seismic sedimentary chronology suggests that the gokova basin is subsiding at 0 3 0 4 mm year three bathymetric low and e w wnw ese directed two main ridges in the gulf area are noticeable from the bathymetric data and are well correlated to the seismic data while the main orientation of the gulf is e w more recent ene wsw and wnw ese structures are remarkable in the western and the mid eastern part of the gulf respectively subsidence rates are greatest in the southern center of the basin and decrease northward so that the northern area is being tilted southward

earthquake mechanisms in the gulfs of gokova sigacik kusadasi and the simav region western turkey neotectonics seismotectonics and geodynamic implications abstract the mechanical behavior of continental lithosphere of aegean region and western turkey is one of the foremost interesting geological disputes in earth sciences this region provides complex tectonic events which produced a strong heterogeneity in the crust as such in among most continental regions the reasons of the ongoing lithospheric scale extension within the aegean region can be revealed by the correlation with the prevailing kinematic and dynamic factors such as roll back of the subduction slab and back arc extension westward extrusion of the anatolian micro plate block rotations and transtensional transform faults seismological studies of earthquake source mechanisms and slip inversions play important roles on deciphering the current deformation and seismotectonic characteristics of the region in recent years several moderate earthquakes have occurred in the gulfs of gokova sigacik kusadasi and simav graben we studied source mechanisms and rupture histories of those earthquakes to retrieve the geometry of active faulting source characteristics kinematic and dynamic fault parameters and current deformations in western turkey we used teleseismic body waveform inversions of long period p and sh and broad band p waveforms we also checked first motion polarities of p waves recorded at both regional and teleseismic stations inversion results revealed e w striking normal faulting mechanisms with small amount of left lateral strike slip components in the gulf of gokova and ne sw oriented right lateral strike slip faulting mechanisms in the gulf of sigacik in simav graben earthquake source parameters show dominantly normal faulting mechanisms with strike slip components our inversions resulted in focal depths for the earthquake ranging from 10 to 15 km and ne sw trending t axes directions the finite fault slip distribution and rupture propagation models exhibit seismic moment releases and large displacement values which essentially occurred at hypocenters of the earthquakes the overall results exhibited uniform and circular shaped rupture propagations along dip directions of fault planes although most of the focal mechanism solutions show dominantly normal faulting mechanisms associated with the e w oriented horst graben structures in western turkey there are also strike slip faulting mechanisms related to remarkable strike slip faults which are capable of generating damaging earthquakes particularly in the gulf of sigacik and karaburun peninsula thus we suggest that present day deformation in the gulfs of gokova sigacik kusadasi and simav graben western turkey is still mainly driven by the n s extensional tectonics but we tentatively further emphasize the importance of strike slip faults in shaping tectonic structures in the aegean region

three dimensional numerical simulation of fluid flow and heat transport within the barbados ridge accretionary complex 1 the thickness of the barbados accretionary prism varies along strike the increased thickness of the prism to the south is believed to affect the transport of heat by fluids resulting in anomalously high heat flow at the deformation front we utilized a coupled three dimensional numerical fluid flow and heat transport model to investigate the effect of variable accretionary prism thickness on fluid flow patterns and heat transport in the decollement zone the variation in sediment thickness produced along strike fluid flow in the more permeable decollement although surface heat flow is higher for simulations where flow occurs along both the decollement and underthrust sediments the resultant advective heat transport was not sufficient to appreciably raise steady state surface heat flow at the latitude of the ocean drilling program transect simulated temperatures in the decollement were consequently much lower than in situ borehole measurements suggesting an additional source of warmer fluid we then investigated the transient hydrologic and thermal response of the system to enhanced fault permeability model results provide insight into the degree to which episodic faulting may drive fluid flow and heat transport within subduction complexes a transient scenario in which decollement permeability was increased two orders of magnitude with fluid flow along both the decollement and underthrust sediments caused the temperature gradient at the location of the drill sites to increase by a factor of two within 7100 years the results of the three dimensional numerical simulations indicate that while both along strike advective heat transport and transient fluid flow events should be considered in the heat flow distribution of the northern barbados accretionary complex the effects of episodic fluid flow are more significant

holocene coastal notches in the mediterranean region indicators of palaeoseismic clustering abstract marine tidal notches are developed by bioerosion in the intertidal zones of rocky coasts but a combination of sea level change and crustal movements can result in them being raised above or submerged below the water line for that reason the present day elevation of these former shorelines relative to the mean sea level has long been used to quantify relative coastal uplift and subsidence in tectonically active areas assuming that the sea level eustatic change component is known along the microtidal mediterranean littoral it is generally assumed that notches develop during relative stillstands of sea level when tectonic and eustatic trends are in unison and that discrete notch levels record abrupt shoreline changes caused by local seismic displacements recently however a climatic model for notch formation has been proposed in which stable periods of holocene climate favour enhanced erosion in this competing model the rate of sea level rise is lower than the tectonic uplift rate and individual notches are not specific seismic indicators because marine notches are widely used as geomorphic markers of tectonic and in some cases palaeoseismic movements a reappraisal of the geological significance of these strandlines is warranted in this paper we explore the two conflicting notch models using a database of eastern mediterranean palaeoshorelines although we conclude that the spatial and temporal distribution of the notches supports a dominantly tectonic control on notch genesis as a result of earthquake clustering we highlight how the diachronous timing of notch development tempers their value as tectonic markers

modeling consolidation and dewatering near the toe of the northern barbados accretionary complex at the toe of the northern barbados accretionary complex temperature and pore water chemistry data indicate that fluid flow is channeled along the decollement and other shallow thrust faults we examine mechanisms that may prevent consolidation and maintain high permeability over large sections of the decollement high resolution bulk density data from five boreholes show that the decollement is well consolidated at some sites while other sites remain underconsolidated underconsolidated decollement behavior is associated with kilometer scale negative polarity seismic reflections from the decollement plane that have been interpreted to be fluid conduits we use a coupled fluid flow consolidation model to simulate the loading response of a 10 km long by 680 m thick slice of sediment as it enters the accretionary complex the simulations capture 185 ka 5 km of subduction with a load function representing the estimated effective stress of the overriding accretionary prism 3 8 taper angle simulation results of bulk density in the decollement 3 2 km arcward of the deformation front are compared with observations the results show that persistent high pore pressures at the arcward edge of the simulation domain can explain underconsolidated behavior the scenario is consistent with previous modeling results showing that high pore pressures can propagate intermittently along the decollement from deeper in the complex simulated seaward fluxes in the decollement 1 14 cm yr 1 lie between previous estimates from modeling studies of steady state 1 m yr 1 flow maximum simulated instantaneous fluid sources 2 5 10 13 s 1 are comparable to previous estimates the simulations show minor swelling of incoming sediments fluid sources 3 10 15 s 1 up to 3 km before subduction that may help to explain small scale shearing and normal faulting proximal to the protodecollement

late miocene recent evolution of the finike basin and its linkages with the beydaglari complex and the anaximander mountains eastern mediterranean abstract interpretation of 2500 km of high resolution multi channel seismic reflection profiles shows that the finike basin evolved during the pliocene quaternary as the result of dramatic subsidence associated with loading of large imbricate thrust panels that carry the western tauride mountains in the north in the late miocene the stacked seaward prograded quaternary deltas presently resting at 1000 1500 m water depths corroborate the rapid subsidence of the region the ubiquitous presence of evaporites in the 2000 2400 m deep antalya basin and their absence in the 3000 3200 m deep finike basin suggest that the morphology of the finike basin and environs must have been considerably different during the messinian and that this region must have remained above the depositional base of evaporites during this time the transition from the messinian to the pliocene quaternary is marked by partitioning of stress into several discrete spatial domains a dextral strike slip fault zone developed along the western antalya basin extending from the apex of the isparta angle southward into the anaximander mountains this fault zone referred to as the antalya fault zone transected the anaximander mountains sensu lato separating the anaxagoras mountain from the anaximander and anaximenes mountains hence the finike basin sirri erinc plateau and the anaximander and anaximenes mountains remained part of the onland beydaglari block and experienced 20 counterclockwise rotation during the late miocene we envisage the boundaries of the beydaglari block as the burdur fethiye fault zone in the west the newly delineated antalya fault zone in the east and the east west trending sector of the sirri erinc plateau in the southwest kinematic evaluation of the structural elements mapped across the finike basin and the sirri erinc plateau suggest that two additional strike slip zones developed during the pliocene quaternary relaying the stress between the antalya fault zone in the east and the pliny strabo fault zone in the west

the 2010 mw 8 8 maule megathrust earthquake of central chile monitored by gps large earthquakes produce crustal deformation that can be quantified by geodetic measurements allowing for the determination of the slip distribution on the fault we used data from global positioning system gps networks in central chile to infer the static deformation and the kinematics of the 2010 moment magnitude m w 8 8 maule megathrust earthquake from elastic modeling we found a total rupture length of 500 kilometers where slip up to 15 meters concentrated on two main asperities situated on both sides of the epicenter we found that rupture reached shallow depths probably extending up to the trench resolvable afterslip occurred in regions of low coseismic slip the low frequency hypocenter is relocated 40 kilometers southwest of initial estimates rupture propagated bilaterally at about 3 1 kilometers per second with possible but not fully resolved velocity variations

smectite and fluid budget at nankai odp sites derived from cation exchange capacity abstract pore fluid chlorinity lower than seawater is often observed in accretionary wedges and one of the possible causes of pore water freshening is the smectite to illite reaction this reaction occurs during diagenesis in the 80 150 c temperature range low chlorinity anomalies observed at the toe of accretionary wedges have thus been interpreted as evidence for lateral fluid migration from inner parts of the wedge and the seismogenic zone however temperature conditions in nankai trough are locally high enough for the smectite to illite transition to occur in situ cation exchange capacity is here used as a proxy for smectite content in the sediment and the amount of interlayer water released during the smectite to illite reaction represents in average 12 water molecules per cation charge water and chloride budget calculations show that there is enough smectite to explain the chlorinity anomalies by in situ reactions the shape of the pore fluid chlorinity profiles can be explained if compaction is also taken into account in the model lateral flow is not needed this argument based solely on chloride concentration does not imply that lateral flow is absent however previous estimations of lateral fluid fluxes and of the duration of transient flow events along the decollement should be reconsidered

geodetic and seismological investigation of crustal deformation near izmir western anatolia abstract the aegean region including western turkey mainland greece and the hellenic arc is the most seismological and geodynamical active domain in the alpine himalayan belt in this study we processed 3 years of survey mode gps data and present the analysis of a combination of geodetic and seismological data around izmir which is the third most populated city in turkey the velocities obtained from 15 sites vary between 25 mm yr and 28 mm yr relative to the eurasian plate the power law exponent of earthquake size distribution b value ranges from 0 8 to 2 8 in the izmir region between 26 2 e and 27 2 e the lowest b value zones are found along karaburun fault b 0 8 and between seferihisar and tuzla faults b 0 8 a localized stress concentration is expected from numerical models of seismicity along geometrical locked fault patches therefore areas with lowest b values are considered to be the most likely location for a strong earthquake a prediction that is confirmed by the 2005 mw 5 9 seferihisar earthquake sequences with epicentres located to the south of the karaburun fault the north south extension of the izmir area is corroborated by extension rates up to 140 nanostrain yr as obtained from our gps data we combined the 3 year gps velocity field with the published velocity field to determine the strain rate pattern in the area the spatial distribution of b value reflects the normal background due to the tectonic framework and is corroborated by the geodetic data b values correlate with strain pattern this relationship suggests that decrease of b values signifies accumulating strain

investigation of the submarine active tectonism in the gulf of gokova southwest anatolia southeast aegean sea by multi channel seismic reflection data submarine active tectonism in the gulf of gokova located at the southwest anatolia southeast aegean sea region was investigated by means of multi channel seismic reflection data the gokova basin is filled by the latest miocene pliocene quaternary sediments with maximum thickness of about 2 5 km the lycian nappes which predominantly cover extreme southwestern anatolia constitutes the basement rocks for the gokova province the gulf was mainly opened by a buried major listric normal fault so called datca fault which has not been previously discussed in the literature the north dipping mainly e w trending datca fault is located at the southern part of the gulf whereas its associated antithetic faults are located at the north the onset time of the opening of the gulf is possibly in the latest miocene pliocene in terms of local rather than regional effects the activity of the datca fault has decelerated possibly since the pleistocene the datca fault might have gained its curved fault plane as it evolved beginning as planar and or using antecedent planes of the lycian nappes in the area as the extension progressed i e as the hanging wall block slipped further north gravity may have impeded rather than helped the faulting on the other hand continuing extension in the area may have initiated a second phase of faulting i e wnw ese oriented subgrabens in the gulf and major e w normal faulting in the northeast margin a bathymetric low in the mid gulf area and a horst graben system in the eastern part of the gulf are observable from the bathymetric data and are well correlated to the seismic data although the main orientation of the gulf is e w more recent wnw ese structures are remarkable in the mid gulf and in the eastern part of the gulf the latest wnw ese structures are also in agreement with the results of gps and slr studies as well as plate motion modelling by total moment tensor of earthquakes in the western anatolia aegean sea region particularly in southwestern anatolia the amount of total n s extension within the gulf is estimated as at least 5 5 km since the latest miocene pliocene with overall constant extension rate of at least 1 1 mm y where the estimated extension factor is about 1 3

generation of layering in the lower stratosphere by a breaking rossby wave 1 an airborne ozone lidar has been used to observe layering in the ozone field between 350 and 400 k northward of the subtropical jet stream an ozone poor layer between 370 and 400 k was observed over western europe on 21 april 1999 on this day a rossby wave was observed to be breaking over the eastern north atlantic and western europe with both poleward and equatorward components we propose that the low ozone at 400 k was caused by a poleward breaking rossby wave stretching from spain to the south coast of britain isentropic back trajectory calculations suggest a tropical upper tropospheric origin for the air within this wave over north america we suggest that rossby waves generate layering in the lower stratosphere because of vertical gradients in the background wind fields which govern the growth in amplitude and breaking characteristics of the waves

gps constraints on active deformation in the isparta angle region of sw turkey summary we use survey and continuous gps observations during the period 1997 2010 to investigate active deformation in the isparta angle region of sw anatolia turkey this region bordered bythefethiyeburdurfaultzone fbfz inthewestandtheseextensionoftheaksehirsimav fault zone aksfz in the east accommodates a part of the active deformation of w turkey our results show that the isparta angle region rotates counter clockwise ccw with respect to anatolia both the fbfz and the aksfz are predominantly transtensional boundaries that accommodate southward motion of the isparta region with respect to anatolia the fbfz has left lateral strike slip behaviour along its sw segment that changes to right lateral strike slip along its ne extension this change in the sense of strike slip motion is accommodated by extension on a nw se striking normal fault system that is associated with the menderes graben system transtensional fault systems along the boundaries of the isparta angle with anatoliaareinconsistentwithextrusionmodelsforpresent daysouthwardmotion anincrease in motion rates towards the hellenic and cyprus arc subduction systems and ccw of the isparta region supports dynamic models involving active rollback of the subducting african plate toroidal mantle flow around the eastern edge of the subducting african slab near the hellenic arc florence rise junction and or gravitational collapse of the overriding anatolia plate

sedimentary evolution of a late pleistocene temperate red algal reef coralligene on rhodes greece correlation with global sea level fluctuations autochthonous red algal structures known as coralligene de plateau occur in the modern warm temperate mediterranean sea at water depths from 20 to 120 m but fossil counterparts are not so well known this study describes from an uplifted coastal section at plimiri on the island of rhodes a 450 m long by 10 m thick late pleistocene red algal reef coralligene facies interpreted as being a coralligene de plateau and its associated deposits the coralligene facies constructed mainly by lithophyllum and titanoderma sits unconformably upon the plio pleistocene rhodes formation and is overlain by a maerl facies 2 m a mixed siliciclastic carbonate facies 0 2 m and an aeolian sand facies 2 5 m the three calcareous facies of heterozoan character are correlated with established members in the lindos acropolis formation in the north of the island while the aeolian facies is assigned to the new plimiri aeolianite formation the palaeoenvironmental and genetic stratigraphic interpretations of these mixed siliciclastic carbonate temperate water deposits involved consideration of certain characteristics associated with siliciclastic shelf and tropical carbonate shelf models such as vertical grain size trends and the stratigraphic position of zooxanthellate coral growths integration of these results with electron spin resonance dates of bivalve shells indicates that the coralligene facies was deposited during marine isotope stage 6 to 5e transgressive event ca 135 to 120 ka in water depths of 20 to 50 m and the overlying maerl facies was deposited during regression from marine isotope stage 5e to 5d ca 120 to 110 ka at water depths of 25 to 40 m the capping aeolian sand facies involving dual terrestrial subunits is interpreted as having formed during each of the glacial intervals marine isotope stages 4 71 to 59 ka and 2 24 to 12 ka with soil formation during the subsequent interglacial periods of marine isotope stages 3 and 1 respectively accumulation rates of about 0 7 mm year 1 are estimated for the coralligene facies and minimum accumulation rates of 0 2 mm year 1 are estimated for the maerl facies the existence of older red algal reefs in the plimiri region during at least marine isotope stages 7 245 to 186 ka and 9 339 to 303 ka is inferred from the occurrence of reworked coralligene type lithoclasts in the basal part of the section and from the electron spin resonance ages of transported bivalve shells

contrasting geothermal regimes of the barbados ridge accretionary complex three e w transects of closely spaced heat flow measurements across the barbados accretionary complex are reported one transect about 100 km in length at 14 20 n and a shorter 15 km line at 14 35 n show that heat flow decreases arcward roughly in proportion to the thickening of the wedge over the actively accreting zone this decrease is due to the combined thermal effects of the underthrusting oceanic lithosphere and thickening of sediments that have been ingested into the wedge except for anomalously high heat flow over a mud volcano on the eastern end of the 100 km transect fluid expulsion appears to have only a secondary effect on the seafloor heat flow in this region an increase of heat flow is observed at the western end of the 100 km transect where high angle arcward vergent thrusting is occurring we attribute this increase primarily to a decrease in the arcward thickening of wedge material and heat generated by friction on the decollement in strong contrast a short line of stations at 15 30 n the deep sea drilling project ocean drilling project dsdp odp drilling transect found anomalously high heat flow a 40 increase over the heat flux from the lithosphere with large variability over the most recently accreted material and also in the adjacent basin the thermal regime in the vicinity of the dsdp odp transect is dominated by a strong flow of pore fluids along the decollement and upward flow along fault planes in the toe of the wedge and adjacent basin sediments heat transport by pore fluids also appears to dominate the subseafloor thermal regime in a zone near 13 50 n the thermal effects of dewatering of the sediments by upward diffusive flow were examined using a simple one dimensional model which showed that the resulting effects are too small to produce detectable heat flow anomalies consequently the flow of fluids must be channelized in subseafloor conduits to produce the observed anomalies in heat flow

deformation of western turkey from a combination of permanent and campaign gps data limits to block like behavior 1 we present a new geodetic velocity field covering western turkey south of the north anatolian fault our velocity field is derived from a combination of continuously recording gps stations operating since 2003 survey type gps measurements carried out in the period 1997 2005 and velocities from reilinger et al 2006 the velocity field indicates that western turkey currently undergoes extension whose rate increases from the anatolia plateau to the aegean coast the overall extension in westernmost turkey is about 20 mm yr making it one of the fastest areas of continental extension in the world we test whether the observed deformation is better represented by the rotation of crustal blocks or by more distributed deformation while no deformation is detected in the central anatolian plateau we observe a deformation field west of the plateau that cannot be explained by block models unless the blocks are so small as to be essentially indistinguishable from a continuum although concentration of strain rates up to 140 nstrain yr are found across the major grabens strain rates above 50 nstrain yr are found throughout western turkey the distributions of topography and crustal thickness in western turkey agree with the distributions expected if the crust there had a constant thickness at 5 ma equal to that of the present central anatolian plateau and had subsequently been thinned at the present day distribution of strain rates our results therefore suggest that extensional strain affects the whole continental lithosphere of western turkey rather than being restricted to a small number of block boundaries

source models of the 2012 haida gwaii canada and 2015 illapel chile earthquakes and numerical simulations of related tsunamis seismological observations provide essential input parameters for numerical tsunami simulations here we present source mechanism parameters finite fault source rupture models and numerical tsunami simulation results for the destructive october 28 2012 haida gwaii canada mw 7 7 and september 16 2015 illapel chile mw 8 3 earthquakes and resulting tsunamis these two earthquakes were controlled by active tectonic features along the subduction zones that had developed in response to the convergent movements of lithospheric plates the faulting geometry strike dip and rake angles focal depth fault dimensions average and maximum slip values on the fault planes and seismic moments of the earthquakes are estimated by analyzing teleseismic long period p and sh waves and broadband p waveforms and using waveform inversion and hybrid back projection methods the obtained slip models of the earthquakes reveal heterogeneous slip distributions on fault planes with long source durations 80 s and 150 s and low stress drop values 10 15 bars numerical simulations of tsunami wave propagation are further performed using the uniform and non uniform slip models and nonlinear long wave equations in spherical coordinates the shape and arrival times of leading tsunami waves are adequately constrained particularly with the heterogeneous slip distribution models the general characteristics of synthetic tsunami waveforms e g amplitude shape arrival time calculated using the non uniform slip model are more consistent with the observed tsunami records than those of a uniform slip model it is further seen that simulation results using preliminary and fast slip models for both earthquakes give only approximate early tsunami estimates tsunami wave heights and arrival times to the coasts are mostly not well simulated the results indicate that tsunami simulations based on finite fault source slip models likely contribute to the determination of tsunamigenic coastal regions by revealing locations arrival times amplitudes and directions of tsunami waves within a close approximation to observed records off shore and far from the source region they provide sufficient information to facilitate tsunami warning and mitigation challenges after the destructive earthquakes we further suggest that joint inversions of gps tsunami teleseismic and strong ground motion records and higher resolution bathymetry data are needed in order to obtain better correlations between observed and synthetic tsunami data especially for the later arriving waves

the tectonic fabric of the barbados ridge accretionary complex abstract a map showing near surface structure and other surficial geological features on the barbados ridge accretionary complex has been constructed from gloria long range side scan sonographs detailed bathymetric surveys using seabeam and single and multichannel seismic reflection sections the map shows major variations in the size orientation and style of structures across the accretionary complex that are principally related to the increasing thickness of the complex and the sediment drape upon it and variations along the complex that derive from the northward thinning of sediment accreted from the ocean floor and the effects of ridges in the oceanic basement the development of crossfaulting is mainly associated with basement ridges mud diapirism is abundant in the southern part of the complex and is characteristic of that part of the complex into which turbidites from the orinoco submarine fan are accreted slumping on a variety of scales is another feature of the complex the map is presented at a scale of 1 1063415 4 inches per degree of longitude and also shows bathymetry at 200 m contour intervals

heat flow tectonics and fluid circulation at the toe of the barbados ridge accretionary prism detailed patterns of near surface tectonics and heat flow were investigated at two locations at the toe of the barbados ridge accretionary prism at the two locations in the thickly sedimented southern portion of the prism near 12 20 n and in the northern area drilled during ocean drilling program odp leg 110 near 15 32 n relative highs of heat flow were associated with zones of thrusting we attribute them to upward advection of water rising from the decollement along faults through the sediments in the odp area a significant heating plate effect from warm fluids flowing along the decollement and thrusts is required to account for the high regional heat flow this effect implies high rates of fluid flow at the decollement which can only be non steady state or would require massive lateral transport of fluids along strike

complex basin evolution in the gokova gulf region implications on the late cenozoic tectonics of southwest turkey southwestern turkey experienced a transition from crustal shortening to extension during late cenozoic and evidence of this was recorded in four distinct basin types in the mugla gokova gulf region during the oligocene early miocene the upper slices of the southerly moving lycian nappes turned into north dipping normal faults due to the acceleration of gravity the kale tavas basin developed as a piggyback basin along the fault plane on hanging wall blocks of these normal faults during middle miocene a shift had occurred from local extension to n s compression transpression during which sediments in the eskihisar tinaz basins were deposited in pull apart regions of the menderes massif cover units where nappe slices were already eroded during the late miocene pliocene a hiatus occurred from previous compressional transpressional tectonism along intermountain basins and yatagan basin fills were deposited on menderes massif lycian nappes and on top of oligo miocene sediments plio quaternary marked the activation of n s extension and the development of the e w trending mugla gokova grabens co genetic equivalents of which are common throughout western anatolia thus the tectonic evolution of the western anotolia during late cenozoic was shifting from compressional to extensional with a relaxation period suggesting a non uniform evolution

discovery of minoan tsunami deposits the hellenic arc is a terrane of extensive quaternary volcanism one of the main centers of explosive eruptions is located on thera santorini and the eruption of the thera volcano in late minoan time 1600 1300 b c is considered to have been the most significant aegean explosive volcanism during the late holocene the last eruptive phase of thera resulted in an enormous submarine caldera which is believed to have produced tsunamis on a large scale evidence suggesting seawater inundation was found previously at some archaeological sites on the coast of crete however the cause of the tsunami and its effects on the area have not been well understood on the aegean sea coast of western turkey didim and fethye and crete gouves we have found traces of tsunami deposits related to the thera eruption the sedimentological consequences and the hydraulics of a thera caused tsunami indicate that the eruption of thera volcano was earlier than the previous estimates and the tsunami did not have disruptive influence on minoan civilization

dip range for intracontinental reverse fault ruptures truth not stranger than friction abstract histograms of fault dips have been compiled for moderate to large m 5 5 reverse slip intracontinental earthquakes with the slip vector raking 90 30 in the fault plane the principal data set is restricted to earthquakes where the fault plane in the focal mechanism can be unambiguously distinguished from the auxilliary plane the reverse fault dips are bracketed within the range 12 1 the observed dip range is consistent with reactivation of faults possessing rock friction coefficients within byerlee9s 1978 range 0 85 s 0 6 undergoing frictional lockup at dips approaching 60 the broad 25 to 35 peak may arise from progressive domino steepening of imbricate reverse faults above the optimal dip for reactivation in regions undergoing bulk shortening paucity of very low angle thrusts implies that it is generally the steeper ramps within ramp flat assemblages that fail in moderate to large earthquakes the subsidiary peak at 45 to 55 likely results from compressional reactivation of former normal faults in areas undergoing tectonic inversion requiring some degree of fluid overpressuring the results are consistent with previous studies on the dip range for active normal faults that again demonstrate frictional lockup at reactivation angles approaching 60 together these analyses suggest that byerlee friction coefficients apply to faults with displacements of up to a few kilometers

tectonics of the hellenic trench a synthesis of sea beam and submersible observations abstract detailed bathymetric investigations were performed in four zones of the hellenic trench system in 1978 using the multi narrow beam echo sounder sea beam on r v jean charcot in 1979 a field study using the 3000 m submersible cyana was conducted in three of the four sites covered by sea beam we summarize here the principal tectonic results of these studies and publish the corresponding sea beam maps it is shown that compressional structures affect the sedimentary cover of the outer wall and trench whereas extensional tectonics is present on the inner wall in addition there is evidence that most of the upper sedimentary cover is not subducted but rather piles up in front of the trench to form the mediterranean ridge we suggest that the surface limit of the zone of mechanical decoupling occurs near the base of the inner wall we show that the gross structure of the trench as well as the strain pattern observed is controlled by the kinematics of subduction and we discuss its evolution since its initiation about 13 m y ago

transient fluid flow through the toe of the barbados accretionary complex constraints from ocean drilling program leg 110 heat row studies and simple models thirty four sediment and mud line temperatures were collected from six drill holes on ocean drilling program odp leg 110 near the toe of the barbados accretionary complex when combined with thermal conductivity measurements from sediment cores and results from earlier surveys these data delineate the complicated thermal structure on the edge of this convergent margin heat flow values at the seafloor of 92 192 mw m sup 2 are 80 300 higher than those predicted by standard heat flow versus age models for oceanic crust but are compatible with earlier seafloor measurements made in this area at the same latitude heat flow tends to decrease downhole at four sites suggesting the presence of heat sources within the sediments these results are consistent with the flow of warm fluids through the complex along high permeability conduits including thrust faults the major decollement zone and sandy intervals simple calculations suggest that this fluid flow is transient occurring on time scales of tens of thousands of years fluid flow velocities along the decollement zone estimated with a simple thermal model are about 10 sup minus 7 m s 100 times faster than predicted by numerical steady state analyses the estimated maximum sediment permeability within the decollement zone which was basedmore on the above fluid flow velocity is about 10 sup minus 12 m sup 2 also 100 times higher that that calculated numerically high heat flow in the vicinity of 15 degree 30 prime n and not elsewhere along the deformation front suggests that the leg 110 drill sites may be situated over a prism water discharge zone with dewatering more active here than elsewhere along the accretionary complex less

a simplified analysis of parameters controlling dewatering in accretionary prisms abstract one of the many dynamic geologic processes taking place at subduction zones is the compaction driven dewatering of seafloor sediments as they are accreted to the overriding plate the rate of dewatering is equal to the divergence of the sediment matrix velocity field this rate can be estimated analytically if simplifying assumptions are made about the geometry of the prism and motion of the sediments the analytical expression depends only on the sediment accretion velocity thickness of the accreted section prism taper angle and sediment porosity distribution a sensitivity analysis of the solution shows that the fluid production distribution is relatively insensitive to the sediment porosity distribution however the solution is very sensitive to the taper angle of the wedge high angle wedges expel almost all of the incoming water within 20 km while low angle wedges may retain a significant fraction of the incoming water for 50 or more kilometers thickness of the incoming section is also important dewatering of thin accreted sections is more concentrated near the toe of the wedge analyses of transects through the northern barbados makran vancouver and nankai accretionary prisms illustrate a range of dewatering rates and spatial distributions of dewatering

the large 1956 earthquake in the south aegean macroseismic field configuration faulting and neotectonics of amorgos island abstract new field observations of the seismic intensity distribution of the large m s 7 4 south aegean amorgos earthquake of 9 july 1956 are presented interpretations based on local ground conditions structural properties of buildings and peculiarities of the rupture process lead to a re evaluation of the macroseismic field configuration this together with the aftershock epicentral distribution quite well defines the earthquake rupture zone which trends ne sw and coincides with the amorgos astypalea trough the lateral extent of the rupture zone however is about 40 smaller than that predicted for aegean earthquakes of m s 7 4 this discrepancy could be attributed to sea bottom topography changes which seem to control the rupture terminations and to relatively high stressdrop with respect to other aegean earthquakes fault plane solutions obtained by several authors indicate either mainly normal faulting with a significant right lateral strike slip component or predominantly strike slip motion the neotectonism of amorgos island based on new field observations aerial photograph analysis and fault mechanisms is consistent with the dip slip interpretation the neotectonic master fault of amorgos and the 1956 seismic faulting appear to belong to the same tectonic phase ne sw strike and a southeasterly dip however the significant right lateral strike slip component supports the idea that the amorgos region deviates from the simple description for pure extension in back arc conditions

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

the chios greece earthquake of 23 july 1949 seismological reassessment and tsunami investigations we present a modern seismological reassessment of the chios earthquake of 23 july 1949 one of the largest in the central aegean sea we relocate the event to the basin separating chios and lesvos and confirm a normal faulting mechanism generally comparable to that of the recent lesvos earthquake located at the northern end of that basin the seismic moment obtained from mantle surface waves m 0 7 times 10 26 dyn cm makes it second only to the 1956 amorgos earthquake we compile all available macroseismic data and infer a preference for a rupture along the nnw dipping plane a field survey carried out in 2015 collected memories of the 1949 earthquake and of its small tsunami from surviving witnesses both on chios island and nearby oinousses and on the turkish mainland while our results cannot help discriminate between the two possible fault planes of the 1949 earthquake an important result is that both models provide an acceptable fit to the reported amplitudes without the need to invoke ancillary sources such as underwater landslides in contrast to the case of other historical tsunamis in the aegean sea such as the 1956 amorgos and 1948 rhodos events

the 2010 mw 7 8 mentawai earthquake very shallow source of a rare tsunami earthquake determined from tsunami field survey and near field gps data 1 the mw 7 8 october 2010mentawai indonesia earthquake was a tsunami earthquake a rare type of earthquake that generates a tsunami much larger than expected based on the seismicmagnitude itproducedalocallydevastatingtsunami withrunupcommonlyinexcess of 6 m we examine this event using a combination of high rate gps data from instruments located on the nearby islands and a tsunami field survey the gps displacement time series are deficient in high frequency energy and show small coseismic displacements 16 m our modeling results show that the combination of the small gps displacements and large tsunami can only be explained by high fault slip at very shallow depths far from the islands and close to the oceanic trench inelastic uplift of trench sediments likely contributed to the size of the tsunami recent results for the 2011 mw 9 0 tohoko oki earthquake have also shown shallow fault slip but the results from our study which involves a smaller earthquake provide much stronger constraints on how shallow the rupture can be with the majority of slip for the mentawai earthquake occurring at depths of 6 km this result challenges the conventional wisdom that the shallow tips of subduction megathrusts are aseismic and therefore raises important questions both about the mechanical properties of the shallow fault zone and the potential seismic and tsunami hazard of this shallow region

gps constraints on continental deformation in the africa arabia eurasia continental collision zone and implications for the dynamics of plate interactions 1 the gps derived velocity field 1988 2005 for the zone of interaction of the arabian african nubian somalian and eurasian plates indicates counterclockwise rotation of a broad area of the earth s surface including the arabian plate adjacent parts of the zagros and central iran turkey and the aegean peloponnesus relative to eurasia at rates in the range of 20 30 mm yr this relatively rapid motion occurs within the framework of the slow moving 5 mm yr relative motions eurasian nubian and somalian plates the circulatory pattern of motion increases in rate toward the hellenic trench system we develop an elastic block model to constrain present day plate motions relative euler vectors regional deformation within the interplate zone and slip rates for major faults substantial areas of continental lithosphere within the region of plate interaction show coherent motion with internal deformations below 1 2 mm yr including central and eastern anatolia turkey the southwestern aegean peloponnesus the lesser caucasus and central iran geodetic slip rates for major block bounding structures are mostly comparable to geologic rates estimated for the most recent geological period 3 5 myr we find that the convergence of arabia with eurasia is accommodated in large part by lateral transport within the interior part of the collision zone and lithospheric shortening along the caucasus and zagros mountain belts around the periphery of the collision zone in addition we find that the principal boundary between the westerly moving anatolian plate and arabia east anatolian fault is presently characterized by pure left lateral strike slip with no fault normal convergence this implies that extrusion is not presently inducing westward motion of anatolia on the basis of the observed kinematics we hypothesize that deformation in the africa arabia eurasia collision zone is driven in large part by rollback of the subducting african lithosphere beneath the hellenic and cyprus trenches aided by slab pull on the southeastern side of the subducting arabian plate along the makran subduction zone we further suggest that the separation of arabia from africa is a response to plate motions induced by active subduction

potential tsunami hazard along the southern turkish coast abstract the aim of this study is to determine the tsunami potential of the southern turkish coast through hypothetical earthquake scenarios developed for several critical coastal sites in the region a well known tsunami numerical model most is utilized to calculate the run up and inundation of the subsequent tsunami waves the coastal regions selected to realize the aim of the study are akkuyu and yesilovacik from mersin and yumurtalik from adana which are chosen for their industrial and environmental importance time series of wave amplitudes at these three sites as well as contour plots presenting maximum wave amplitudes within the computational domain are generated for different earthquake moment magnitudes results obtained from the numerical model suggest that while earthquakes having magnitude smaller than 7 5 generate weak oscillations earthquakes with magnitude greater than 7 5 result in significant waves reaching maximum wave height of a few meters at the selected coastal regions given the number and the magnitude scale of tsunamigenic earthquakes occurred in the region in the past the modeling effort here indicates that hazard induced by tectonic tsunamis should seriously be taken into account by both the central and the local government authorities who are responsible for pre and post disaster action planning this issue is critical for minimizing the damage of a possible tsunami event the proposed study is hoped to be used as a basis for future tsunami risk maps to be developed for the region

the 20th july 2017 bodrum kos tsunami field survey the july 20 2017 bodrum kos earthquake caused tsunami wave motions and damage in the south of bodrum peninsula turkey and on kos island greece immediately after the earthquake we conducted several post tsunami field surveys including interviews in coastal zones impacted by the tsunami i e the coastlines of bodrum peninsula karaada islet and akyaka town in gokova bay turkey and eastern kos island greece we present observations and measurements to document the variation of the tsunami effects along the coast the largest tsunami runup was about 1 9 m and observed at the mouth of a small dry streambed at gumbet bay bodrum no significant water motions were reported at the northern and western coasts of bodrum peninsula the tsunami runup distribution along the coast of eastern kos was overall regular with runup not exceeding 1 m except in the port of kos where a 1 5 m tsunami runup was measured

heat flow and thermal models of the barbados ridge accretionary complex the pattern of heat flow from the barbados ridge accretionary complex has been derived from marine surveys with heat flow probes from measurements in drill holes and from the depths of bottom simulating seismic reflectors caused by gas hydrate the heat flow from the accretionary complex has been simulated using a finite difference model to investigate how heat flow responds to changes in the cross sectional shape of the complex and the rate of convergence and to variations in pore fluid pressure within the complex and along the decollement at its base in the south of the complex heat flow decreases westward from the toe of the wedge towards the island arc because the downward movement of subducting lithosphere beneath the wedge and the active thickening of the accreted sedimentary sequence reduce the geothermal gradient more rapidly than thermal diffusion can maintain it localised high anomalies attributed to the flow of warm fluids along fault zones are superimposed on the conductive heat flow pattern farther west heat flow increases arcward produced partly by thermal diffusion re establishing a steeper thermal gradient where the rate of thickening is decreased but mainly by the arcward increase of frictional heating along the base of the wedge caused by the increase of slip rate and increased normal stress arising from thickening of the wedge in the north of the complex around the odp leg 110 drill sites the conductive model cannot reproduce the anomalously high heat flow measurements which can only be explained by the advection of warm pore fluids

an assessment of along strike fluid and heat transport within the barbados ridge accretionary complex results of preliminary modeling in this investigation we examined the effects of the three dimensional geometry of the barbados ridge accretionary complex on decollement zone fluid flow and thermal transport modeling results indicate that fluid preferentially escapes the decollement zone through the thin sediment layer north of the tiburon rise this drain produces a northerly along strike component of fluid flow in the vicinity of the deep sea drilling project dsdp and ocean drilling program odp transect depending on pore pressure ratios on the arcward boundary of the complex the along strike component can reach half the magnitude of the component perpendicular to the deformation front thermal advection along oblique flow paths would result in significantly higher decollement temperatures at the deformation front than indicated by cross sectional models constructed perpendicular to the deformation front