an ensemble approach for improved short to intermediate term seismic potential evaluation pattern informatics pi load unload response ratio lurr state vector sv and accelerating moment release amr are four previously unrelated subjects which are sensitive in varying ways to the earthquake s source previous studies have indicated that the spatial extent of the stress perturbation caused by an earthquake scales with the moment of the event allowing us to combine these methods for seismic hazard evaluation the long range earthquake forecasting method pi is applied to search for the seismic hotspots and identify the areas where large earthquake could be expected and the lurr and sv methods are adopted to assess short to intermediate term seismic potential in each of the critical regions derived from the pi hotspots while the amr method is used to provide us with asymptotic estimates of time and magnitude of the potential earthquakes this new approach by combining the lurr sv and amr methods with the choice of identified area of pi hotspots is devised to augment current techniques for seismic hazard estimation using the approach we tested the strong earthquakes occurred in yunnan sichuan region china between january 1 2013 and december 31 2014 we found that most of the large earthquakes especially the earthquakes with magnitude greater than 6 0 occurred in the seismic hazard regions predicted similar results have been obtained in the prediction of annual earthquake tendency in chinese mainland in 2014 and 2015 the studies evidenced that the ensemble approach could be a useful tool to detect short to intermediate term precursory information of future large earthquakes

oxygen diffusion in amphiboles the kinetics of oxygen isotope self diffusion in natural samples of hornblende tremolite and richterite have been measured samples were run under hydrothermal conditions using 18o enriched water profiles of 18o 16o 18o vs depth into the crystal were obtained using an ion microprobe the depths of sputtered holes were measured using an optical interferometer at 1000 bars 100 mpa water pressure the activation energies q and pre exponential factors d0 for diffusion parallel to c are d0 cm2 sec q kcal gm atom t c hornblende 1 20 1 10 741 6 650 800 tremolite 2 30 2 10 8 39 5 650 800 richterite 3 5 2 10 4 57 2 650 800 the diffusion coefficient d for hornblende at 800 c and 1000 bars water pressure measured parallel to the c crystallographic direction is at least ten times greater than that parallel to the a or b directions an increase in water pressure from 200 to 2000 bars increases d by a factor of 2 7 for diffusion parallel to c at 800 c the d value for hornblende at 800 c is about 0 01 that for quartz and 0 001 that for anorthite as a result closure temperatures for oxygen exchange in natural primary amphiboles are significantly higher than for quartz or feldspars it is unlikely that amphiboles will exchange oxygen isotopes by diffusion under most crustal conditions

petrogenesis of the swaziland and northern natal rhyolites of the lebombo rifted volcanic margin south east africa thejozini and mbuluzi rhyolites and oribi beds of the southern lebombo monocline southeastern africa have geochemical characteristics that indicate they were derived by partial melting of a mixture of high ti zr and low ti zr sabie river basalt formation types compositional variations within the different rhyolite types can largely be explained by subsequent fractional crystallization the srand nd isotope composition of the rhyolites is unique amongst gondwana silicic large igneous provinces having end values close to bulk earth 0 94 to 0 35 and low but more variable initial sr sr ratios 0 7034 0 7080 quartz phenocryst do values indicate that the rhyolite magmas had do values between 5 3 and 6 7o consistent with derivation from a basaltic protolith with do values between 4 8 and 6 2o the low do rhyolites 56 0o come from the same stratigraphic horizon and are overlain and underlain by rhyolites with more normal do magma values these low do rhyolites cannot have been produced by fractional crystallization or partial melting of mantle derived basaltic material the rhyolites have low water contents making it unlikely that the low do values are the result of post emplacement alteration modification of the source by fluid rock interaction at elevated temperatures is the most plausible mechanism for lowering the do magma value it is proposed that the low do rhyolites were derived by melting of earlier altered rhyolite in calderas situated to the east which were not preserved after gondwana break up

late quaternary evolution of the northern aegean shelf abstract a dense network of 3 5 khz and uniboom seismic profiles revealed the geological evolution of the ierissos alexandroupolis shelf area of the northern aegean during the latest sea level rise near the end of the pleistocene ca 14 000 yr b p the sea was at about 120 m and almost 5300 km2 of shelf was exposed to subaerial erosion two permanet lakes existed in the ierissos and kavalla gulfs as well as a number of ephemeral lakes scattered throughout the rest of the area kavalla gulf was drained by the nestos river which joined the strymon river at the outer strymonikos plateau on the flat samothraki plateau were dune fields marshes and a number of minor seasonal rivers while the evros river flowed east of the plateau by ca 13 000 yr b p the sea had risen to 70 m and covered 30 of the previously exposed shelf the lakes at ierissos and strymonikos gulfs were shallower and the sea approached to within about 5 km of them kavalla gulf and the adjacent eastern strymonikos plateau lay 10 m above sea level while the sea intruded along river mouths at the samothraki plateau during this transgression of the sea river bed gravels and sands were covered by silts and clays at the pleistocene holocene transition ca 10 500 yr b p the sea lay at about 50 m and in areas of steep slope the coast was close to its present position at kavalla gulf the sea advanced along the paleochannel of the nestos river and the island of samothraki was separated from the mainland by ca 7500 yr b p the sea was only 15 m below its present level and the northeastern aegean shelf assumed nearly its present morphology the nestos river changed course to the east and thassos island was separated from the mainland coarse sediment formed wedges nearshore whereas fine grained sediments were distributed widely by current action in many areas relict sediments are present

oxygen diffusion in quartz diffusional oxygen exchange between quartz and water was studied by determining 18o profiles in the quartz using an ion microprobe inverse error function plots of the data are linear as required for a diffusion mechanism one natural and two synthetic samples were used and although they had different impurity concentrations oh na and al per 106 si atoms are 7 4000 35 835 and 67 127 respectively the d values were the same within experimental uncertainty diffusion parallel to c is about 2 orders of magnitude faster than that normal to c at 700 c and diffusion normal to the rhombohedron is intermediate the data indicate a change in slope on an arrhenius plot at the boundary at 100 mpa 1 kbar water pressure the preexponential factors do in square centimeters per second and activation energies q in kilojoules per mole for quartz 500 550 c are as follows do 190 and q 284 parallel to c and do 8 10 2 and q 238 normal to the rhombohedron for quartz 600 800 c do 4 10 7 and q 142 parallel to c do 9 10 7 and q 155 normal to the rhombohedron and do 1 10 4 and q 234 normal to c d increases with ph 2 o and between 25 and 350 mpa log d versus log h 2 o has a slope of approximately 1 1 these d values are all several orders of magnitude larger than previously reported values for oxygen diffusion in water free systems

probabilistic forecasting of earthquakes we present long term and short term forecasts for magnitude 5 8 and larger earthquakes we discuss a method for optimizing both procedures and testing their forecasting effectiveness using the likelihood function our forecasts are expressed as the rate density that is the probability per unit area and time anywhere on the earth our forecasts are for scientific testing only they are not to be construed as earthquake predictions or warnings and they carry no official endorsement for our long term forecast we assume that the rate density is proportional to a smoothed version of past seismicity using the harvard cmt catalogue this is in some ways antithetical to the seismic gap model which assumes that recent earthquakes deter future ones the estimated rate density depends linearly on the magnitude of past earthquakes and approximately on a negative power of the epicentral distance out to a few hundred kilometres we assume no explicit time dependence although the estimated rate density will vary slightly from day to day as earthquakes enter the catalogue the forecast applies to the ensemble of earthquakes during the test period it is not meant to predict any single earthquake and no single earthquake or lack of one is adequate to evaluate such a hypothesis we assume that 1 per cent of all earthquakes are surprises assumed uniformly likely to occur in those areas with no earthquakes since 1977 we have made specific forecasts for the calendar year 1999 for the northwest pacific and southwest pacific regions and we plan to expand the forecast to the whole earth we test the forecast against the earthquake catalogue using a likelihood test and present the results our short term forecast updated daily makes explicit use of statistical models describing earthquake clustering like the long term forecast the short term version is expressed as a rate density in location magnitude and time however the short term forecasts will change significantly from day to day in response to recent earthquakes the forecast applies to main shocks aftershocks aftershocks of aftershocks and main shocks preceded by foreshocks however there is no need to label each event and the method is completely automatic according to the model nearly 10 per cent of moderately sized earthquakes will be followed by larger ones within a few weeks

development of a combination approach for seismic hazard evaluation we developed a synth esis approach to augment current techniques for seismic hazard evaluation by combining four previously unrelated subjects the pattern informatics pi load unload response ratio lurr state vector sv and accelerating moment release amr methods since the pi is proposed in the premise that the change in the seismicity rate is a proxy for the change in the tectonic stress this method is used to quantify localized changes surrounding the epicenters of large earthquakes to objectively quantify the anomalous areas hot spots of the upcoming events on the short to intermediate term estimation we apply the lurr sv and amr methods to examine the hazard regions derived from the pi hot spots a predictive study of the 2014 earthquake tendency in chinese mainland using the seismic data from 1970 01 01 to 2014 10 01 shows that during jan 01 to oct 31 2014 most of the m 5 0 earthquakes especially the feb 12 m7 3 yutian may 30 m6 1 yingjiang aug 03 m6 5 ludian and oct 07 m6 6 earthquakes occurred in the seismic hazard regions predicted comparing the predictions produced by the pi and combination approaches it is clear that by using the combination approach we can screen out the false alarm regions from the pi estimation without reducing the hit rate and therefore effectively augment the predictive power of current techniques this provided evidence that the multi method combination approach may be a useful tool to detect precursory information of future large earthquakes

deglacial warming of the northeastern atlantic ocean correlation with the paleoclimatic evolution of the european continent abstract isotopic micropaleontologic and pollen analyses of deep sea cores from the bay of biscay and the northeastern atlantic ocean show that the deglacial warming of this oceanic area was closely correlated with the paleoclimatic evolution of the adjacent european continent temperatures were at least as warm as those of today in the bay of biscay between 13 300 and 11 000 b p coinciding with the combined bolling allerod warm continental events a major spread of polar water occurred between 11 000 and 10 000 b p during this event which coincides with the younger dryas continental cold event marine temperatures were almost as low as those of the last glacial maximum the final deglacial warming of the norteastern atlatntic ocean occurred during the following 3000 yr

seismic stratigraphy of the fault controlled submarine canyon valley system on the shelf and upper slope of anamur bay northeastern mediterranean sea abstract high resolution shallow seismic reflection uniboom and echosounding profiles obtained on the shelf and upper slope areas of anamur bay turkey northeastern mediterranean were studied together with previous data on the onshore geology of the area to investigate the origin and related seismic stratigraphy of the submarine anamur canyon it was found that the main axial trend of the submarine anamur canyon is aligned with the offshore projection of the n s orientated onshore anamur thrust fault of late cretaceous senonian to early tertiary age interpretation of the distinct reflection configurations observed on the seismic profiles reveals the presence of various seismic facies comparable with the depositional sequences resulting from the relative sea level changes during the late quaternary the acoustic basement probably miocene in age is overlain by a sedimentary column mainly plio quaternary which in turn can be divided into two major seismic sequences and 12 seismic facies that show considerable variations in both their lateral and horizontal extent a palaeo deltaic environment sequence i with its typical topset and foreset facies was recognized and the corresponding deposits are interpreted to be indications of coastal deltaic progradation during late pleistocene sea level highstands or during the early phases of the last major eustatic lowering reflections of sequence ii which includes nine distinct facies are marked by onlap configuration and are believed to be marine deposits of the flandrian transgression at least four transgressive cycles are evident from the seismic profiles at 70 90 60 45 and 40 m water depths the two sequences i and ii are now covered with the most recent facies

late glacial holocene palaeoceanography of the sea of marmara timing of connections with the mediterranean and the black seas abstract stratigraphic analysis of late quaternary sediments of the sea of marmara basin smb indicates that it was a freshwater lake during the late glacial to ca 12 000 yr bp depositing sediments with a neoeuxinian fauna characteristic of the black sea basin at ca 12 000 yr bp it was inundated by the mediterranean waters and gradually converted into a marine realm as indicated by the presence above the neoeuxinian sediments of a mixed layer containing both marine and freshwater fauna a sapropelic sediment layer was deposited between 10 600 and 6400 yr bp under suboxic bottom water conditions this layer roughly corresponds in time to s1 sapropel unit of the eastern mediterranean suggesting a common origin its presence in the smb therefore supports the hypothesis that a large influx of freshwaters from the black sea was an important factor in sapropel formation in the eastern mediterranean a second sapropelic layer formed in the smb during 4750 to 3200 yr bp the earliest known record of mediterranean water in the bosphorus is at ca 5300 yr bp suggesting a later marine inundation than the 7150 yr bp event suggested by ryan and co workers an abrupt drowning of black sea shelf at 7 5 kyr bp geo eco marina 2 proc int workshop on fluvial marine interactions mainas romania 1 7 october 1997 pp 115 125 and ryan w b f pitman iii w c major c o shimkus k moskalenko v jones j a dimitrov p gorur n sakinc m yuce h 1997b an abrupt drowning of black sea shelf mar geol 138 1997 119 126 this implies that either earlier marine connections with the black sea were through a different waterway or the earlier marine record in the strait has been eroded the present two layer flow system was established at 4000 yr bp

middle and late holocene sea levels along the israel mediterranean coast evidence from ancient water wells during the course of a study of historical water wells along the israeli shore which has been in progress since 1984 an innovative method for investigating sea level fluctuations was developed eighteen ancient water wells were re dug 14 by the author and four by archaeologists most of the re dug wells are found at archaeological sites located a very short distance inland from the present shoreline evidence of ancient ground water levels found in the wells directly reflects on historic eustatic sea level changes and the rate at which the end of the post glacial transgression advanced a critical question concerns the durability and life span of these wells as the true age is very important for the accurate reconstruction of a sea level curve the pre pottery neolithic well of atlit yam which is the oldest known well in the world ca 8000 yr old enabled the most accurate sea level reconstruction for early holocene times sea level rise during that period of the atlit yam site was of the order of 20 mm yr 1 at the beginning slowing to 6 8 mm yr 1 at the abandonment of this site at ca 7 5 ka bp when it was flooded by the advancing and rising sea after reaching its present level sea level fluctuations for the past 2 5 millennia were not greater than 1 5 to 2 m 1997 john wiley sons ltd

evaluation of palaeoenvironmental changes during the last 18 000 years in the myrtoon basin sw aegean sea abstract high resolution last glacial maximum to holocene palaeoenvironmental changes corresponding to a time interval between 200 and 500 years are examined in the myrtoon basin in the sw aegean sea using the abundance variation in foraminifera and pollen in relation to accelerator mass spectrometry 14 c dating and limited oxygen isotope data foram abundance variation shows that from 18 ka to the late glacial holocene boundary at around 10 5 to 9 5 ka the sea surface was cold during this period two intervals of relatively high and low sea surface temperature sst were observed the first high sst occurred at around 14 2 ka whereas the second high sst was centred at around 12 8 ka and appears to correspond to the termination 1a event the first low sst was centred at around 13 7 ka and the second low sst occurred between 11 8 and 10 8 ka the former event may correspond to the heinrich 1 event and the latter to the younger dryas chronozone the holocene started with a sharp warming of sea surface water reaching present day levels and probably associated with a reduction in salinity the formation of the sapropel sequence in the myrtoon basin started at about 10 ka about the same time as the sapropel formation in the other aegean basins which means that the environmental conditions became suitable for the formation of sapropels in the aegean about 800 years earlier than in the adriatic ionian and levantine basins within the sapropel sequence there are two high organic carbon corg content sublayers s 1 a 9 7 9 ka and s 1 b 7 3 6 9 ka separated by a lower corg content sublayer indicating variation in the oceanographic and climatic conditions prevailing in the area during the sapropel sequence formation the depositions of s 1 a and s 1 b coincide with an increase in sst increased temperature and enhanced fresh water inputs from the outflowing rivers in to the aegean sea which later was supplemented by the overflowing of the black sea lowered the sea surface density and reduced the vertical water masses circulation resulting in reduced bottom water ventilation the reduction of o 2 supply to the seabed in combination with increased fluxes of terrigenous and or marine organic matter were responsible for the creation of dysoxic to anoxic conditions in the seabed which led to the formation of sapropel s 1 the sapropel formation ended at 5 2 ka and about the same time the sst attained present day levels during the last glacial maximum and late glacial periods the pollen source area was providing a suitable environment for the growth and survival of arboreal taxa the source area was apparently ice free and was characterized by sufficient humidity and non lethal low temperatures probably only a few degrees colder than present day

late quaternary climate and sea level changes recorded in sediment composition off the buyuk menderes river delta eastern aegean sea turkey abstract influences of holocene climatic and sea level changes on sedimentation on the continental shelf off the buyuk menderes river delta sw turkey were investigated using grain size and x ray clay mineralogical data on surficial and 14c dated core sediments collected at 19 81 m water depths modern fine grained siliciclastic sediments cover most of the seafloor of inner to mid shelf areas a narrow relict belt extends from northwest to south at 66 81 m water depths where sediments are characterized by abundant sand and gravel 27 52 and biogenic carbonate 16 44 contents and microscopic examination suggests an older origin the radiocarbon ages of mid and lower sections in cores 3670 10 380 yr bp reflect sedimentation under depositional conditions from early to late holocene in the study area additionally downcore changes of grain size toward coarser grained sediments most probably record global climatic effects with sea level changes specifically the transition from lowstand in early holocene to highstand at mid late holocene the presence of this relict belt in offshore waters can be attributed largely to active uplift tectonics the coarser grained relict belt compared with available seismic profiles corresponds to an lowstand unconformity of bottomset beds of the prograding buyuk menderes delta reconstruction from nautical charts clearly showed the presence of an e w trending submarine canyon paleo buyuk menderes river valley in the course of buyuk menderes graben this is interpreted as product of combination of sea level lowstands and subsidence tectonics throughout the late quaternary smectite 35 62 illite 28 51 and kaolinite 12 19 constitute the dominant clay minerals in the

high resolution seismic reflection profiles for the reconstruction of postglacial transgressive shorelines an example from greece abstract in 1982 we carried out a shallow penetration high resolution seismic profiling study on the shelf of the southern argolid peloponnesos greece to identify and map the shores of the late pleistocene and holocene and to establish their coastal environments portable equipment and a local boat were used the lowest glacial shore occurs at 115 to 118 m within the range of global values the subsequent rise across the distinct old land surface left behind many shore features scaps beaches and beach ridges channels and lagoons now buried under a few meters of post transgressive deposits these features cluster at a small number of depths below present sea level suggesting that the rise of the sea usually too fast to leave an imprint was episodically interrupted by brief stillstands or even temporary reversals of climatic or tectonic origin the clusters can be roughly dated with reference to a global sea level rise curve after 6000 yr b p sparse archaeological data establish a local curve the seismic profiling technique convenient and not costly holds promise for the identification of postglacial shores elsewhere prior to sampling for dating it has wide application for environmental reconstructions of vanished coastal zones as a basis for prehistoric resource assessments these applications are illustrated with examples from this study

zircon u pb dating of water rock interaction during neoproterozoic rift magmatism in south china abstract a combined study of zircon u pb dating and mineral o isotope analysis was carried out for neoproterozoic granite gabbro and gabbrodiorite from the beihuaiyang zone that marks a rifted margin between the south china block and the supercontinent rodinia the results provide precise constraints on timing of water rock interaction resulting in unusual 18 o depletion in igneous minerals cl imaging reveals that zircons mostly show clear oscillatory and or sector zoning with or without thin alteration rims no metamorphic zircon occurs in the igneous intrusives although they suffered greenschist facies metamorphism during triassic continental collision la icpms zircon u pb dating yields consistent ages of 739 8 to 754 5 ma which are interpreted as timing of magma crystallization mineral separates have highly variable 18 o values of 0 6 to 6 8 for zircon 1 2 to 12 5 for quartz and 0 3 to 8 4 for plagioclase oxygen isotope heterogeneities exist within single intrusions and between different intrusions magmatic zircons with low 18 o values and a weighted mean u pb age of 748 6 ma crystallized from low 18 o magmas that were derived from melting of hydrothermally altered low 18 o rocks both low and normal 18 o intrusives in the beihuaiyang zone are shown to form at the same time contemporaneous with the rodinia breakup thus tectonic evolution from supercontinental rift to breakup is proposed to create conditions for alternating processes of high t hydrothermal alteration and low 18 o magmatism such processes are a characteristic feature of high t water rock interaction in volcanic rift margins associated with localized water saturated melting while the occurrence of low 18 o magmas demonstrates penetration of meteoric water into the rift tectonic zone of crustal melting the existence of normal 18 o magmas indicates that their emplacement may serve as a thermal engine to drive the second stage of meteoric water rock interaction resulting in the unusual 18 o depletion in adjacent rocks the concurrent occurrence of both low and normal 18 o magmas appears to indicate highly heterogeneous high t water rock interaction during rift magmatism

evolving towards a critical point a review of accelerating seismic moment energy release prior to large and great earthquakes there is growing evidence that some proportion of large and great earthquakes are preceded by a period of accelerating seismic activity of moderate sized earthquakes these moderate earthquakes occur during the years to decades prior to the occurrence of the large or great event and over a region larger than its rupture zone the size of the region in which these moderate earthquakes occur scales with the size of the ensuing mainshock at least in continental regions a number of numerical simulation studies of faults and fault systems also exhibit similar behavior the combined observational and simulation evidence suggests that the period of increased moment release in moderate earthquakes signals the establishment of long wavelength correlations in the regional stress field the central hypothesis in the critical point model for regional seismicity is that it is only during these time periods that a region of the earth s crust is truly in or near a self organized critical soc state such that small earthquakes are capable of cascading into much larger events the occurrence of a large or great earthquake appears to dissipate a sufficient proportion of the accumulated regional strain to destroy these long wavelength stress correlations and bring the region out of a soc state continued tectonic strain accumulation and stress transfer during smaller earthquakes eventually re establishes the long wavelength stress correlations that allow for the occurrence of larger events these increases in activity occur over longer periods and larger regions than quiescence which is usually observed within the rupture zone of a coming large event the two phenomena appear to have different physical bases and are not incompatible with one another

high resolution seismic profiling in the sea of marmara northwest turkey late quaternary sedimentation and sea level changes high resolution sparker seismic profiling was carried out in the sea of marmara northwest turkey to study the late quaternary tectonics and sedimentation of this important active basin at the western end of the north anatolian fault zone a sedimentary unit interpreted as the clinoforms of a prograding delta was observed in places along the outer part of the southern shelf the topset foreset transitions of the latest clinoforms cluster around 100 m below present sea level they were probably deposited during the last glacial maximum and early phase of deglaciation between 25 and 13 k y b p when the level of the aegean was below that of the dardanelles sill 60 70 m below sea level at present therefore the sea of marmara was isolated from the aegean during the last glacial maximum but it is possible that a fluvial overflow existed across the dardanelles during this time stabilizing the level of the marmara lake and allowing the delta progradation rivers that drain into the sea of marmara from the south have a much greater combined drainage basin area and sediment flux than those draining the region to the north this may explain the much broader shelf to the south half graben bounded by north dipping normal faults observed within the southern shelf would tend to trap sediment sourced from the south and subdue any sea bed morphology on the shelf

fluid flow deformation rates and the submarine record of major earthquakes in the sea of marmara along the north anatolian fault system abstract the submerged portions of the north anatolian fault naf in the sea of marmara and the ne aegean sea are sites of large magnitude earthquakes that leave diagnostic geological signatures in the sedimentary record in the form of mass wasting deposits turbidites and fluid and gas escape features this is due to the interplay of seismic shaking mass and turbidity flows sediment resuspension and fluids circulation in relatively small sub basins with a complex paleo oceanography steep slopes high rates of deformation and diffuse fault controlled gas and fluid seeps to unravel the complex interrelations of these phenomena during earthquake cycles we carried out paleoseismological studies at several key locations here we report results of these studies carried out onboard the r v urania over a decade starting soon after the mw 7 4 1999 izmit earthquake our work included high resolution mapping of active faults through multibeam bathymetry and high resolution seismic reflection profiles multi parameter analysis of sediment cores as well as seafloor observations using sensors mounted on remotely operated vehicles rov the main objectives were to map active faults determine slip rates and earthquake recurrence times along major fault strands and assess connections between fault deformation and fluid activity we mapped fault geometry in the gulfs of izmit gemlik and saros showing the trans tensive nature of these depressions the average slip rates for the last 10 ka was found to be 10 mm y in the gulfs of izmit and saros at the eastern and the western ends of the naf northern strand and 3 4 mm yr in the gulf of gemlik along the middle strand of the naf these rates integrated over 10 ka of naf activity are smaller than those determined by the gps geodetic measurements submarine paleoseismological studies in the gulf of izmit detected the sedimentary records of earthquakes for the last 2 4 ka suggesting an average recurrence time of 300 years for major events multisensor observations and monitoring of the seafloor have shown widespread emissions of gas and fluids along the submerged part of the naf associated with reduced black sediments we investigated their possible connection with the earthquake cycle

late quaternary depositional history of the north evvoikos gulf aegean sea greece a high resolution seismic reflection survey was carried out in the north evvoikos gulf a deep 450 m semi enclosed basin in east central greece connected to the aegean sea via a 45 m sill to the north and a 30 m wide 10 m deep straight to the south this active extensional basin is bound by major normal faults that switch polarity along strike thereby controlling the asymmetric shape of the basin the survey records show a continuous upper unit in the marine strata deposited since the post glacial transgression on an erosion surface generated during the last glacial the upper unit can be traced downslope into the basin plain where it merges into a unit of laterally continuous interbedded turbidites and hemipelagic deposits the buried erosion surface has many terraces distributed over several depth zones between 65 m and 165 m below present sea level that are evidence for a fluctuating water level when in the last glacial interval the sill depth in the north was about 55 m below today s sealevel and the gulf became isolated from the aegean sea thus during the last 70 kyr the water level of the lowstand lakes fluctuated in correspondence with the oxygen isotope stages ois and the climatic conditions in the dryer stages ois 4 2 the lake water level was lower in the wetter stages ois 1 3 the lake water level was higher these events are also correlated with sediment budgets input from the surrounding land to the basin researches carried out in many other gulfs of variable depth in the ionian and aegean seas indicated presence of sills at today s depths between 50 and 70 m the generation of these features is postulated as sedimentary as many sea level fluctuations ranged in this depth interval

multi methods combined analysis of future earthquake potential prior to an earthquake natural seismicity is correlated across multiple spatial and temporal scales many studies have indicated that an earthquake is hard to accurately predict by a single time dependent precursory method in this study we attempt to combine four earthquake prediction methods i e the pattern informatics pi load unload response ratio lurr state vector sv and accelerating moment release amr to estimate future earthquake potential the pi technique is founded on the premise that the change in the seismicity rate is a proxy for the change in the underlying stress we first use the pi method to quantify localized changes surrounding the epicenters of large earthquakes to objectively quantify the anomalous areas hot spots of the upcoming events next we delineate the seismic hazard regions by integrating with regional active fault zones and small earthquake activities then we further evaluate the earthquake potential in the seismic hazard regions using the lurr sv and amr methods retrospective tests of this new approach on the large earthquakes m 6 5 which have occurred in western china over the last 3 years show that the lurr and sv time series usually climb to an anomalously high peak months to years prior to occurrence of a large earthquake and the asymptote time t c predicted by the amr method correspond to the time of the actual events the results may suggest that the multi methods combined approach can be a useful tool to provide stronger constraints on forecasts of the time and location of future large events

quaternary transgressive regressive cycles in the gulf of argos greece abstract borings in the argive plain reveal cycles of marine incursions each ending with a mediterranean soil profile and followed by a prograded fluvial and coastal wedge the sediment prism of the gulf of argos shelf visible in high resolution seismic reflection profiles also consists of transgressive and regressive depositional sequences identified by onlap downlap and truncation of deposits at least four major reflectors recognizable by their high acoustic impedance and erosional features can be correlated across the shelf the sediments between each pair of reflectors represent the seaward part of a set of transgressive and regressive marine deposits they can be matched to the stratigraphic sequence on land where each marine unit is topped by a soil corrected for subsidence the terminations of the onlapping and downlapping units define a local sea level history its time scale can be derived from a comparison with the eustatic sea level history deduced from ocean cores thus marine seismic reflection data can be used for the correlation of quaternary oceanic and terrestrial chronologies

chronology of quaternary shoreline progradational sequences related to eustatic sea level changes sedimentation and subsidence in saronikos gulf greece abstract the stacking pattern of shoreline progradational sequences in subsiding basins have been used as a chronologic tool in the mediterranean region most previous studies have used a few key seismic lines seaward of deltas where the record is complicated by deltaic distributary switching southeastern saronikos gulf in the western aegean sea at the northwestern end of the south aegean arc lacks large river input of sediment the ene wsw and nw se trending neotectonic aegina and methana basins lie between the tectonically active gulf of corinth and the relatively stable cyclades plateau new high resolution seismic profiles from southeastern saronikos gulf have been interpreted according to the principles of seismic and sequence stratigraphy alpine basement and marine pliocene sediments have been recognized in the surrounding basin margins and more than 300 m and 150 m of unconsolidated sediments have been mapped in aegina and methana basin respectively progradational clinoforms that toplap against transgressive surfaces have been traced along strike leading to the establishment of a robust chronostratigraphic framework further controlled by sedimentation rates as extracted from cores southeastern saronikos gulf poses an outstanding example of development of progradational wedges formed within a microtidal wave dominated regime of low sedimentation rates between 2 8 cm ka and 3 2 cm ka within the framework of low subsiding basins with rates between 0 03 and 0 31 m ka in this environment more than 180 well preserved shoreline progradational units with attributes similar to the ones reported from the aegean and eastern mediterranean seas have been mapped and correlated to sea level lowstands back to 866 ka deeper mid pleistocene progradational units are also recognized tentatively back to 1 4 ma subsidence rate shows a dramatic decrease in the last 1 ma and significant numbers of faults became inactive during the last 130 ka in early middle quaternary methana basin was an isolated lake and extended terrestrial areas were shaped in the poros agios georgios plateau during sea level lowstands aegina basin was continuously connected to the aegean through the agios georgios fault valley this study demonstrates the robustness of chronology based on stacked shoreline progradational sequences and its applicability to determining rates of tectonic subsidence

the high resolution palaeoclimatic and palaeoceanographic history of the last 24 000 years in the central aegean sea greece abstract the palaeoclimatic and palaeoceanographic history of the n skyros basin central aegean sea was studied based on the planktonic foraminifera and the stable isotopes obtained from the sediments of a sediment core selected in this area the data were further supported by pollen and dinoflagellate cyst data the data correspond to a mean sampling interval of about 170 yrs and cover the last 24 000 yrs the variations in almost all of the records showed synchronicity suggesting the occurrence of a series of climatic changes the most pronounced climatic changes during the last glacial and late glacial periods are as follows i a brief relatively warm and humid event at 19 5 kyr ii two cold spells at 17 ka and 15 8 ka iii the climatic oscillation during the gi 1 event and iv the development of the younger dryas gs 1 event in two phases during the holocene epoch five brief cold and or arid phases occurred at around 10 5 ka 8 2 ka 7 ka to 6 ka 5 0 ka and 3 0 ka the most warm and humid holocene events correspond to the time of the deposition of the two sapropel sublayers s1a and s1b almost all of these brief climatic changes are coeval with equivalent changes in high northern latitude areas and with changes in the intensity of the siberian high suggesting a climatic link between the studied area and the high latitude areas the prevalence of holocene arid events which coincide with equivalent events recorded in north eastern africa and the middle east suggests a climatic link between the eastern and south eastern regions of the mediterranean sea

load unload response ratio and accelerating moment energy release critical region scaling and earthquake prediction the main idea of the load unload response ratio lurr is that when a system is stable its response to loading corresponds to its response to unloading whereas when the system is approaching an unstable state the response to loading and unloading becomes quite different high lurr values and observations of accelerating moment energy release amr aer prior to large earthquakes have led different research groups to suggest intermediate term earthquake prediction is possible and imply that the lurr and amr aer observations may have a similar physical origin to study this possibility we conducted a retrospective examination of several australian and chinese earthquakes with magnitudes ranging from 5 0 to 7 9 including australia s deadly newcastle earthquake and the devastating tangshan earthquake both lurr values and best fit power law time to failure functions were computed using data within a range of distances from the epicenter like the best fit power law fits in amr aer the lurr value was optimal using data within a certain epicentral distance implying a critical region for lurr furthermore lurr critical region size scales with mainshock magnitude and is similar to the amr aer critical region size these results suggest a common physical origin for both the amr aer and lurr observations further research may provide clues that yield an understanding of this mechanism and help lead to a solid foundation for intermediate term earthquake prediction

diffusion effects on oxygen isotope temperatures of slowly cooled igneous and metamorphic rocks recently obtained data on oxygen diffusion in feldspars quartz and hornblende permit the prediction of the apparent18o16o temperatures that would be measured in a rock that consisted only of those three minerals and cooled slowly from high temperature the computed temperatures would be based on the differences in the18o16o ratios between coexisting pairs of minerals the present calculation takes into account the diffusion rates for oxygen as a function of temperature the cooling rate of the rock the mineral grain sizes and the mode of the rock for mineral grains 1 mm in radius and a cooling rate of 10 c m y the minimum difference in apparent temperature between quartz feldspar and feldspar hornblende pairs will be 115 c despite the assumption of a normal uneventful slow cooling history to room temperature further the apparent quartz hornblende temperature will range over 30 c 590 620 c depending on the mode of the rock for a cooling rate of 1000 c m y the apparent difference in temperature can be as much as 400 c consequently consistency in temperatures obtained by oxygen isotope analysis should not be expected in most high grade metamorphic rocks or igneous rocks which are cooled slowly departures from the pattern of temperatures obtained in this model would imply a very rapid quench from high temperature or a complex history for the rock for some minerals including hornblende the relation between temperature and the equilibrium fractionation of oxygen isotopes between coexisting phases has been derived from observed relations in natural specimens the choice of the specimens used for such calibrations needs to be re evaluated in light of these findings this may result in a change in the equilibrium equation constants an example from the literature the san jose tonalite baja california mexico was modelled and yields 18o concentrations in the minerals that correspond closely with the measured values this suggests that the model used is appropriate that the rock has had a simple thermal history and that it cooled at 100 200 c m y over the temperature range 800 500 c the set of paleotemperatures obtained for a rock will in general yield neither the mineral closure temperatures nor the formation or crystallization temperatures on the other hand the cooling rate of the rock may be derived from the data this in turn may have important tectonic implications with regard to denudation and uplift rates

quaternary sedimentary history and neotectonic evolution of the eastern part of central aegean sea greece abstract four distinct unconformities can be traced below the e cyclades margins s ikarian basin that separate four oblique progradational delta sequences these have been deposited during sea level lowstands within middle late quaternary glacial stages oxygen isotopic stages 2 6 and possibly 12 8 22 16 the topset foreset transition of these sequences located at 110 152 and 212 m below present sea level reflect continuous subsidence of the s ikarian margins with a calculated rate of 0 33 0 57 m kyr 1 the mean sedimentation rates were estimated as 20 90 cm kyr 1 for the late pleistocene turbiditic deposits 250 kyr b p today for the post isotopic 6 128 kyr b p today sediments the accumulation rates were 10 30 cm kyr 1 on the slopes and 45 60 cm kyr 1 within the basins while for the post late glacial sediments 18 kyr b p today the calculated maximum accumulation rates were 30 cm kyr 1 within the basins and 6 14 cm kyr 1 within the basin margins of north and south ikarian basins a pronounced compressional phase during the middle early quaternary within the north and south ikarian basin can be recognised within the n ikarian basin indications of quaternary strike slip deformations appeared to be related with en echelon of transpressional reverse faults from the middle quaternary onward continuous subsidence and the reduction in size of subaerial regions are attributed to extension tectonics

chemical and thermal constraints on focussed fluid flow in the lower oceanic crust the mechanism of heat extraction from the lower oceanic crust near the ridge axis is poorly constrained despite its importance for understanding both the process of accretion of the plutonic complex and the mass fluxes associated with ridge hydrothermal systems we have investigated the role of zones of focussed fluid flow in the plutonic complex of the oman ophiolite in the near axis cooling of the oceanic crust lineaments identified on aerial photographs that occur at 1 km spacing show evidence for extensive hydrothermal fluid flow through regions 10 to 50 m wide fluid flow is initiated in these regions at 800 c and continues at least into the lower greenschist facies strontium isotope analyses indicate that the fluid flux through these zones is sufficient to transport a metasomatic front from the base of the sheeted dike complex to close to the moho computed minimum fluid fluxes to transport a metasomatic front through the focussed fluid flow zones are 1x108 kgm2 modeling of diffusive exchange of calcium from olivine to clinopyroxene indicates enhanced cooling rates adjacent to the focussed fluid flow zones heat fluxes estimated from the enhanced cooling rates are broadly consistent with the fluid fluxes determined from modeling the sr isotopic composition of samples from the focussed fluid flow zones the combination of independent estimates of the fluid and heat fluxes such as these can provide more rigorous constraints on the thermal history than either approach used in isolation our results show that focussed fluid flow could play a major role in the cooling in the lower oceanic crust significant focussed fluid flow in the lower oceanic crust has important implications for predicting the total mass flux associated with hydrothermal circulation at mid ocean ridges this is because fluids flowing through channels become chemically rock buffered at smaller fluid fluxes than those flowing pervasively through a rock mass thus if focussed fluid flow is an important mechanism of heat loss from the lower oceanic crust the chemical fluxes from ridge hydrothermal systems into the oceans may be smaller than currently thought

origin of the strait of canakkale dardanelles regional tectonics and the mediterranean marmara incursion abstract the regional tectonics and the mid to late quaternary seismic stratigraphy of the strait of canakkale dardanelles and its opening towards the aegean sea were interpreted by using shallow seismic profiles this strait is a narrow valley that resulted from regional uplift of the gelibolu and biga peninsulas in the pliocene as a consequence of compressional events generated by strike slip faulting activity of the ganos fault a northern strand of the north anatolian fault a nne ssw trending fault system between eceabat and canakkale believed to result from the left lateral displacement of the ganos fault on the gelibolu peninsula cut this valley into different segments the connection between the marmara basin and the aegean sea has been achieved after flooding of the connected valleys during the mid to late pleistocene three major sea level lowstands 130 150 m during this period 600 kyear bp interrupted the sea water connection at least twice three main seismic unconformities detected in the sediments of the strait of canakkale represent these lowstands minor sea level lowstands could have induced narrowing of the strait and erosion of depositional units the recent geological history of the strait of canakkale appears as deduced from the gelibolu peninsula and its western regions strongly related to escape tectonics influenced by the compressional forcing of the anatolian block in addition it also shows a morphological evolution which carries the effects of the global sea level variations

recent sedimentation on the shelf and upper slope in the bay of anamur southern coast of turkey abstract sedimentological studies supported by uniboom profiles and sonographs of surface sediments from a part of the narrow southern shelf of anatolia indented by the head of a submarine canyon and partly covered by meadows of macrophytobenthos revealed abrupt lateral and vertical variations in the holocene sedimentary facies these variations have essentially been controlled by the migration of depocentres palaeo topography of the shelf and an overall decrease in the rate of fluviatile sediment supply in the late holocene as sea level reached approximately its present position nearly 5 ka b p the bulk of the siliciclastic input began to be trapped in the inner shelf zone most of the terrigenous mud bypasses the shelf to be trapped in the canyon head but transport of modern detrital sand and gravel does not take place across the shelf this is because of the relative weakness of the onshore offshore currents the prevailing microtidal conditions and a belt of phytobenthos between 10 and 30 m which traps the sediments the plants also create the ecological conditions favourable for biological carbonate production however some gravel and sand size relict sediments have been transported from the outer shelf into the canyon head by gravity induced or cross canyon currents the mudline occurs at about the 100 m isobath marking the deepest limit of effective bottom turbulence for the resuspension of silt and clay on the shelf

state vector a new approach to prediction of the failure of brittle heterogeneous media and large earthquakes the concept of state vector stems from statistical physics where it is usually used to describe activity patterns of a physical field in its manner of coarsegrain in this paper we propose an approach by which the state vector was applied to describe quantitatively the damage evolution of the brittle heterogeneous systems and some interesting results are presented i e prior to the macro fracture of rock specimens and occurrence of a strong earthquake evolutions of the four relevant scalars time series derived from the state vectors changed anomalously as retrospective studies some prominent large earthquakes occurred in the chinese mainland e g the m 7 4 haicheng earthquake on february 4 1975 and the m 7 8 tangshan earthquake on july 28 1976 etc were investigated results show considerable promise that the time dependent state vectors could serve as a kind of precursor to predict earthquakes

a new approach to earthquake prediction the load unload response ratio lurr theory the response to loading is different from that to unloading when the focal media is approaching instability the ratio of the response rate during loading to that during unloading called load unload response ratio y lurr could be a measure of the closeness degree to instability and is used in a new approach to earthquake prediction retrospective examination of some one hundred earthquake cases from m 4 to m 8 6 indicates that for more than 80 of the examined ones the value of y is much higher than 1 for a period before the main shock but the y value always fluctuates slightly about 1 during two decades for seven stable regions so that the parameter y could indicate a dangerous degree of an impending earthquake several earthquakes occurring on the chinese mainland in recent years as well as the northridge california u s a earthquake jan 17 1994 m w 6 7 have been predicted beforehand with this method

quaternary tectonics of the argolikos gulf and adjacent basins greece a single channel seismic reflection survey of the argolikos gulf and idhra channel casts light on the tectonic history of this extensional basin of which the current subsidence phase is less than 0 5 ma old although the gulf has very low seismicity holocene subsidence on the western boundary faults increases southward from 50 to 100 cm ka 1 the eastern margin of the gulf is offset eastward twice for these offsets we postulate two left lateral strike slip faults accommodating a southward increase in the extension rate these features can be traced on land where at least one of them shows evidence of left lateral movement the idhra channel has a different tectonic pattern of e w trending extensional troughs separated by basement ridges the latter diverge westward and continue into the southern argolid as mesozoic limestone ridges separated by ophiolite floored tectonic valleys the causes of this discordant pattern remain obscure

late quaternary evolution of the gulf of patras greece tectonism deltaic sedimentation and sea level change abstract the gulf of patras is an actively subsiding late cenozoic graben in western greece that receives deltaic sediment from the large acheloos and evinos rivers the late quaternary sedimentation history of the gulf is interpreted from 3 5 khz profiles numerous short cores and airgun seismic profiles a widespread unconformity represents the isotopic stage 2 marine lowstand when the gulf was subaerially exposed subsequent deltaic progradation and associated coastal transgression was greatest during the 13 10 5 ka slowdown in sea level rise and the period of stable sea level since the mid holocene switching of delta distributaries can be related to the known evolution of the subaerial parts of the deltas the stage 2 unconformity provides a datum for quantitative determination of rates of subsidence the central graben is subsiding at rates of 3 5 mm yr rates in the northern part of the gulf average 1 2 mm yr this is consistent with a listric faulting model for the origin of the modern patras graben

oscillating quaternary water levels of the marmara sea and vigorous outflow into the aegean sea from the marmara sea black sea drainage corridor abstract detailed interpretation of single channel air gun and deep tow boomer profiles demonstrates that the marmara sea turkey experienced small amplitude 70 m fluctuations in sea level during the later quaternary limited in magnitude by the sill depth of the strait of dardanelles moderate subsidence along the southern shelf and quaternary glacio eustatic sea level variations created several stacked deltaic successions separated by major shelf crossing unconformities which developed during the transitions from global glacial to interglacial periods near the strait of dardanelles a series of sand prone deposits are identified beneath an uppermost holocene transparent mud drape the sandy deposits thicken into mounds with the morphology and cross sectional geometries of barrier islands sand waves and current generated marine bars all cross stratification indicates unidirectional flow towards the dardanelles prior to the deposition of the transparent drape which began 7000 years bp in strong support of the notion that the marmara sea flowed westwards into the aegean sea through the dardanelles at times of deglaciation in northern europe the global sea level curve shows that at 11 000 and 9500 years bp sea level rose to the sill depths of the straits of dardanelles and bosphorus respectively the effect from 11 000 to 9500 years bp was seawater incursion into the marmara sea drowning and formation of algal serpulid bioherms atop lowstand barrier islands and transgression of shelves and lowstand deltas at 9500 years bp glacial meltwater temporarily stored in the black sea lake developed into a vigorous southward flow toward the aegean sea forming west directed sandy bedforms in the western marmara sea and initiating deposition of sapropel s1 in the aegean sea this strong outflow persisted until 7000 years bp after which a mud drape began to accumulate in the marmara sea and euryhaline mediterranean mollusks successfully migrated into a progressively more saline black sea where sapropel deposition began most eastern mediterranean sapropels from s1 to s11 appear to correlate with periods of rising sea level and breaching or near breaching of the bosphorus sill these events are believed to coincide with times of vigorous outflow of low salinity fresh surface waters transiting the black sea marmara sea corridor and ultimately derived from melting of northern european ice sheets

geological slip rates along the north anatolian fault in the marmara region 1 reliable piercing points on both sides of the sea of marmara enabled us to obtain an estimate of the slip rate over time scales of 10 15 ka on different fault strands of the north anatolian fault naf system we analyzed geomorphic features in the gulfs of izmit gemlik sea of marmara and saros ne aegean sea which were passively displaced by the naf strands after their abandonment related to the post glacial sea level rise results for the main northern strand consistently similar on both sides of the marmara pull apart are in the order of 10 mm yr about one half of that expected from geodetic measurements and accepted plate tectonic models in the southern branch of the naf the estimated rate of 4 mm yr is only slightly higher than that given by geodetic models our findings have implications for both neo tectonic reconstructions of the submerged portion of the naf system and fault interactions and seismic hazard estimates in the marmara region they suggest that either the total anatolia eurasia plate motion is more diffuse than previously reported or geodetic data are not representative of the geological time scale deformations moreover they suggest that a significant amount of stress is accommodated along the southern strand of the naf system on which the last large m 7 earthquakes dates back to 1419 1855 and 1863 ad

development of a new approach to earthquake prediction load unload response ratio lurr theory the seismogenic process is nonlinear and irreversible so that the response to loading is different from unloading this difference reflects the damage of a loaded material based on this insight a new parameter load unload response ratio lurr was proposed to measure quantitatively the proximity to rock failure and earthquake more than ten years ago in the present paper we review the fundamental concept of lurr the validation of lurr with experimental and numerical simulation the retrospective examination of lurr with new cases in different tectonic settings california usa and kanto region japan the statistics of earthquake prediction in terms of lurr theory and the random distribution of lurr under poisson s model finally we discuss lurr as a parameter to judge the closeness degree to soc state of the system and the measurement of tidal triggering earthquake the load unload response ratio lurr theory was first proposed in 1984 yin 1987 subsequently a series of advances were made yin and dyin 1991 yin 1993 yin et al 1994a b 1995 maruyama 1995 in this paper the new results after 1995 are summarized yin et al 1996 wang et al 1998a zhuang and yin 1999

deglacial co2 buildup constraints on the coral reef model abstract the coral reef hypothesis of degalcial co2 buildup in the atmosphere can account for about one half of the signal seen in ice cores assuming additional coral reef growth releases 2 atmospheric carbon masses acm the carbonate dissolution signal on the deep sea floor suggest titration of only 1 acm at least 4 acm of co2 must be made available to satisfy the requirements of pco2 increases growth of biosphere and of sedimentary carbon pool carbonate dissolution on the sea floor and saturation of newly introduced meltwater a drop in ocean fertility is called for to provide the missing co2 such a drop is evident in deep sea cores from the western equatorial pacific co2 buildup appears to occur as a step near 13 500 years b p dissolution on the deep sea floor begins near 11 000 years b p the difference of 2500 years may describe a mixing lag due to meltwater input the worthington effect

late pleistocene and holocene sea level change in greece and south western turkey a separation of eustatic isostatic and tectonic contributions summary sea level change during late pleistocene and holocene times is a combination of eustatic isostatic and tectonic contributions in the central mediterranean sea region of greece and western turkey the isostatic components are important due to the changing gravitational potential of the earth the readjustment of the crust upon the removal of the large ice sheets and the addition of the meltwater into the oceans including the mediterranean changes in relative sea level due to these glacio hydro isostatic adjustments have reached amplitudes of 1 mm yr 1 during the last few thousand years a model for the isostatic contribution to sea level change including the movement of shorelines due to the combined eustatic isostatic changes is developed based on earth model and ice sheet parameters estimated from sea level observations from other areas comparisons of this model with observations of sea level change permit rates of vertical movement to be estimated for late holocene time allowance for the isostatic factors makes a significant difference to these rates the plains of argolis lakonia messinia and navarine in the southern peloponnese for example appear to be tectonically stable on time scales of a few thousand years and longer consistent with the position of the last interglacial shoreline close to the present day sea level the observations here of a rising sea level are largely the consequence of the glacio hydro isostasy and not of a long term tectonic process crete as a whole is subject to tectonic uplift but at variable rates and forms part of an arcuate zone of uplift extending from rhodes and karpathos in the east to kithera in the west at rates that locally exceed 4 mm yr 1 the southern shore of the gulf of corinthos is also subject to uplift at rates approaching 1 5 mm yr 1 these isostatically corrected estimates for the past few thousand years are in agreement with longer term estimates based on the position of the last interglacial shoreline only on the perachora peninsula do the tectonic rates over these two time intervals appear to be in disagreement with the late holocene rates being much higher than the long term rates

archaeology of the continental shelf marine resources submerged landscapes and underwater archaeology we provide a critical review of the evidence for the long term use of marine resources and coastal environments in human evolution and later development we emphasise the importance of the coastal archaeological record in understanding patterns of human settlement and dispersal and draw attention to the large potential biases introduced by the destructive or obscuring effects of pleistocene sea level change we note that lowered sea levels have been the norm for most of the pleistocene and that periods of high sea level have been too short lived to provide other than a fragmentary coastal record and one that is beset with ambiguities and uncertainties we examine the geological processes of coastal uplift and underwater preservation that may help to mitigate these biases coastlines elevated by isostatic and tectonic processes or with very steep offshore drop offs at plate boundaries are important in providing a potential window into coastal landscapes and archaeology formed during periods of lowered sea level however we conclude that the opportunities afforded by these geological factors are too limited to obviate the need for underwater exploration we review the evidence now available from submerged landscapes across the africa eurasia interface from the atlantic coastlines of northwest europe to the southern red sea we show that geomorphological conditions for the preservation of archaeological and palaeoenvironmental data are commonly present that much material has already been discovered and that new techniques technologies and projects are providing the momentum for a rapidly expanding field of investigation the results do not simply add to what we already know from sites on land but are likely to produce qualitatively different evidence for coastal adaptations and landscapes that have no analogue on present day coastlines we note the strong probability that many coastal landscapes exposed at lowered sea level provided relatively fertile and productive refugia for plants land mammals and humans at a time when increased aridity would have reduced or deterred hinterland occupation we conclude that underwater investigation is essential if hypotheses of early human adaptation and dispersal are to be fully tested

late quaternary depositional architecture of po and tevere river deltas italy and worldwide comparison with coeval deltaic successions abstract po and tevere rivers form two of the most important deltas of the whole mediterranean area detailed investigations have been carried out in the last decade beneath the present delta plains of these two river systems using borehole data correlation with the aid of radiocarbon dates and other dating methods pollens archaeology a detailed sequence stratigraphic framework has been constructed in both areas especially for the last glacial interglacial cycle regional subsidence combined with short term sea level fluctuations of relatively high amplitude played a fundamental role in creating subtracting accommodation during the long phase of falling sea level which followed the tyrrhenian substage 5e transgressive event a discontinuous record of this phase is present in the subsurface of the po plain whereas poor or no preservation has been detected in the tevere area progradational lowstand wedges accumulated during the last glacial maximum mostly in the central part of the basins far from the present deltas and are lacking in the study areas where a hiatal surface is invariably recorded below the transgressive deposits glacioeustasy exerted a major control on sedimentation in both areas during the latest pleistocene holocene sea level rise infilling of fluvial valleys and rapid landward migration of barrier lagoon systems in the context of wave dominated estuaries characterized the transgressive phase in both po and tevere systems in place drowning and transgressive submergence mechanisms of barrier migration were effective predominantly between 13 5 and 9 ka bp in contrast shoreface retreat was dominant in the late transgressive phase the maximum flooding surface mfs can be traced physically from continental to marine deposits and has similar characteristics in the po and tevere river systems being marked by peat layers or lagoonal deposits at landward locations and by distinctive lithological characteristics and micro and macrofossils assemblages basinwards above the mfs the early highstand systems tract records initially the filling of the lagoons followed by the rapid progradation of wave dominate delta systems and flanking strandplains autocyclic processes such as distributary channel avulsion delta lobe abandonment and local subsidence due to sediment compaction were the fundamental controlling factors on sedimentation during deposition of the hst the stratigraphic architecture of the post glacial po and tevere delta complexes closely resembles the basic facies successions documented from coeval deposits of wave dominated and wave influenced clastic coasts both locally within the mediterranean area and in other parts of the world our study emphasizes however some additional features and major differences with previously published depositional models including i the development of backstepping wave dominated estuaries during transgression ii consistent changes through time in the mechanism of barrier migration iii a later construction of the delta systems with respect to what traditionally considered

late pleistocene unconformity in the gulf of kavalla northern aegean greece abstract a 147 cm core from the gulf of kavalla on the northern aegean shelf displays two different lithologies separated by an erosional contact the upper part 0 128 cm consists of clayey silt to silty clay grading into silty sand and represents a neritic to nearshore marine environment the lower section 128 147 cm is a stiff calcareous mudstone with scattered microcrystalline calcite nodules and probably represents part of a subaerial soil horizon b ca seismic data indicate that at this location the unconformity between the late glacial subaerial surface and the overlying post glacial transgressive deposits occurs at a depth of 150 cm and has apparently been sampled by the core

short term climate changes in the southern aegean sea over the last 48 000 years abstract high resolution palaeoenvironmental changes corresponding to a mean time interval of 450 years covering the last 48 000 years were examined in a core from the cretan basin in the southern aegean sea the intensity and duration of the climatic and oceanographic events were determined by examining the compositional changes in the planktonic foraminifera and pollen assemblages along with the 18o signal of globigerinoides ruber a reconstruction of sea surface temperatures was attempted using the modern analogue technique mat in total 10 stadials and 6 interstadials occurred over the last 48 000 years these fluctuations in climatic conditions coincide with fluctuations documented in the western and central mediterranean and seem to be associated with dansgaard oeschger events some of these climatic fluctuations are correlated with changes in the vegetation in the surrounding land between 48 and 10 cal kyr bp the most pronounced stadials occurred at 41 cal kyr bp c69 st10 and at 13 cal kyr bp c69 st4 these events are characterized by i high positive 18o values of globigerinoides ruber ii drops in sst and iii increases in aridity these events may be correlated with the heinrich h4 event and the younger dryas event respectively two other stadials at 23 cal kyr bp c69 st6 and at 16 cal kyr bp c69 st5 which are characterized by increases in the abundance of the cold plaktonic foraminifera species and increases in aridity may be correlated with the h2 and h1 events respectively the dominant planktonic foraminiferal species during the stadials witch are correlated with the heinrich events were turborotalita quinqueloba and globorotalia scitula the most pronounced interstadials occurred between 39 5 and 38 5 cal kyr bp c69 ist6 and between 25 and 24 cal kyr bp c69 ist3 and are characterized by depletion in 18o values increases in sst and increases in humidity the former event coincides with the formation of the sapropelitic layer s2 in the holocene the most pronounced stadial occurred between 8 and 6 5 cal kyr bp c69 st2 during the interruption of s1 and is characterized by a reduction in sst and an increase in aridity the most pronounced interstadials of holocene occurred during the formation of s1a and s1b between 9 and 8 cal kyr bp c69 ist1 and between 6 5 and 5 5 cal kyr bp c69 ist2 respectively these events are characterized by depletion in 18o values increased sst and an increase in humidity as is indicated by the expansion of temperate evergreen and mediterranean taxa in the pollen record

rates and mechanisms of isotopic exchange background the proliferation of stable isotope laboratories in recent years has led to a marked increase in the routine use of stable isotope analyses in geochemical studies this trend is likely to continue because of the development of micro analytical techniques e g laser ablation ion microprobe femtomole carrier gas methods etc for stable isotope analysis and the potential of these techniques to reveal the detailed sequence of thermal and fluid histories preserved in the rock record see mckibben et al 1998 equilibrium isotope fractionation factors and rates of isotopic exchange form the cornerstones for the interpretation of stable isotope data from natural systems indeed determination of the distribution of the stable isotopes of c o h s in gases fluids and minerals has become a standard and extremely powerful approach in elucidating the temperatures material fluxes rock and fluid origins and time scales associated with ancient and active fluid rock interaction processes in the earth s crust see valley et al 1986 although the thermodynamic principles underlying isotopic fractionation behavior were developed more than fifty years ago by urey 1947 the calibration of fractionation factors has proven to be difficult during the last four decades a great deal of progress has been made in determining the equilibrium fractionations of 18o 16o d h 13c 12c and 34s 32s among fluid and mineral components at high temperatures 400 c both from experimental exchange studies theoretical calculations using vibrational spectra semi empirical calculations using bond type considerations and empirical calibrations based on natural assemblages see references in o neil 1986 kyser 1987 criss 1991 1999 chacko et al this volume of these the experimental method is the most direct because it involves the least number of a priori assumptions despite the utility of the equilibrium approach in quantifying the isotopic behavior in select water rock

filling up the shelf a sedimentary response to the last post glacial sea rise abstract following the last glacial maximum lgm lowstand global sea level rose by 120 m flooding previously exposed continental shelves worldwide with water and sediments in these drowned environments sediment accumulation patterns are dictated by a superposition of vertical tectonic motion sea level change and sediment supply rates which are hard to distinguish from one another this study focuses on a unique region where the first two components are known and well constrained the terminal part of the nile littoral cell along the eastern mediterranean continental margin data analysis is based on detailed interpretation of four newly obtained high resolution seismic reflection surveys integrated with two industrial seismic surveys the age of sedimentary sequences is constrained by correlation with drillholes while accumulation patterns strongly correlate with the local model based sea level curve our sub meter resolution seismic stratigraphy reveals post lgm shoreline migration and suggests a seismic based sea level curve since data presented here provide the first direct insight into the sedimentary accumulation pattern they are used to calibrate the modeled curve this simple yet innovative approach stresses the importance of high resolution seismic reflection data to sea level research worldwide while serving as a reference for the entire mediterranean sea

earthquake rupture as a critical point consequences for telluric precursors abstract earthquakes are related to rupture phenomena in complex statistical systems of cracks we first review some available information suggesting that rupture in earthquakes is a critical point the consequences of this hypothesis on several phenomena are then discussed in particular we focus our attention on a simple theory of electroseismic activity based on mechano electrical transduction effects such as the piezoelectric or the pressure induced polarization effect the neighbourhood of the rupture threshold is characterized by a specific response which could correspond to telluric wave activity observed as precursors of earthquakes

physical basis for statistical patterns in complex earthquake populations models predictions and tests understanding the physics of earthquakes and the space time patterns they produce is illuminated by the use of coarse grained models and simulations that capture the basic physical processes and that are amenable to analysis we present a summary of ideas that describe the nucleation growth and arrest of earthquakes on individual faults under shear loading we find that faults reside in a metastable state near a classical spinodal that governs the nucleation and growth of slip events the roughness of an associated stress distribution field x t determines whether slip events are confined within the initial high stress patch or break away and grow to become very large we find a critical value of roughness that is associated with a first order order disorder transition we also give a number of predictions examples and applications of these ideas and indicate how they might be tested through systematic observational programs

late pleistocene holocene sediments on the spanish continental shelves model for very high resolution sequence stratigraphy abstract sequence stratigraphy analysis of high resolution seismic profiles geopulse uniboom and 3 5 khz of late pleistocene holocene sediments has been carried out on five sectors of the spanish continental margin four types of depositional settings are distinguished in these sectors 1 low subsident ramps alboran margin cadiz gulf 2 high subsident 2m kyr ramps alicante valencia 3 ria type morphology on the atlantic passive margin ria de muros and 4 fault scarp morphology systems with subsidence balearic margin a type 1 sequence is interpreted in all these sectors being composed of lowstand systems tract transgressive systems tract and highstand systems tract this conforms to the basic concepts of sequence stratigraphy and each systems tract correlates with a particular part of the last eustatic hemicycle characteristic shelf features such as terraces terraces with beach deposits and progradational sediment wedges evidence a complex stacking of lesser sub sequences in all the systems tracts which must be related to very short period sea level stillstands and fall we propose a very high resolution sequence stratigraphy model in which the last sea level hemicycle is punctuated by p cycles 4500 years which give rise to the neo glacial events h cycles 2200 950 years and c cycles 500 50 years these cycles interact with each other thus establishing the placing of the high and low sea levels this attention to detail 1 explains sedimentary evolution on both the shelf and upper slope during late pleistocene holocene time 2 illustrates some departures from the classical sequence stratigraphy model and 3 also demonstrates that the late pleistocene holocene eustatic curve is not one simple transgression but is modulated by three differing period cycle groups below the milankovitch band our model is delimited by fluctuating sea level during pleistocene holocene times such features should be identifiable on any continental margin however localized features occur due to subsidence and continental shelf morphology which determ ine the location and depth of sedimentary bodies generated in each eustatic cycle

box cores from the equatorial pacific 14c sedimentation rates and benthic mixing abstract carbon 14 determinations on box cores of calcareous ooze from the western and eastern equatorial pacific suggest that patterns of mixed layer ages sedimentation rates and mixed layer thicknesses are controlled by gradients of carbonate dissolution and fertility and by small scale redeposition processes mixed layer ages range from 3000 to 7000 years with a mode between 4000 and 5000 years sedimentation rates range from 0 8 to 2 4 cm 1000 years mixed layer depths calculated according to the box model of mixing range from 7 cm to 16 cm observed thicknesses are about one fourth smaller than calculated ones

oxygen self diffusion in quartz under hydrothermal conditions oxygen self diffusion dox has been monitored in single crystal quartz in the temperature range 515 850 c under hydrothermal conditions in the beta field between 700 and 850 c the data are represented by two linear arrhenius relations for transport parallel and perpendicular to c values for do m2 s 1 are 2 09 10 11 parallel to c and 3 16 10 10 perpendicular to 101 0 values for h kj mol 1 are 138 54 parallel to c and 203 72 perpendicular to 101 0 at 700 c in the total pressure range 11 5 100 mpa dox is independent of water f h2o and oxygen f o2 fugacities between the ni nio and fe3o4 fe2o3 buffers the results are consistent with diffusion via a simple charged vacancy mechanism under an extrinsic point defect regime further experiments are required to confirm the nature of the mobile oxygen defect a key aspect of the results is the observation that at the low water fugacities of the present experiments a hydrogen containing defect appears to play no role in the oxygen transport mechanism this is in contrast to other published sets of data and leads directly to the requirement for detailed interlaboratory comparisons

sea level changes and related depositional environments on the southern marmara shelf abstract petrographic data obtained from 182 surface sediment samples together with the available bathymetric data are used to investigate the effects of the last major sea level changes on shelf evolution in the southern sea of marmara grain size analysis reveals the presence of at least three belts or zones which are rich in coarse grained sand and gravel sediments these coarse grained belts which are up to 45 km long 15 km wide show up to 20 m of relief and are presently found at 40 80 m average 60 m water depths based on microscopic examination and residual analysis the sediments from these belts are interpreted as indicators of high energy shallow waters where detrital siliciclastics with some benthic contribution accumulated the presence of a 62 65 m deep sill in the canakkale strait and the consideration of sea level curves would suggest that the marmara shelves must have been subaerially exposed down to 65 m water depths for about 10 000 yrs 22 000 12 000 yrs b p sufficient time to modify former shelf topographies and form such bottom relief while difficult to date we believe that coarse grained belts found on the southern marmara shelf must be relict i e former shorelines beaches and their formation is largely related to low stands of sea level during the late pleistocene regression and early holocene transgression however the available high resolution seismic profiling data suggest that the neotectonism in this seismically active sea of marmara plays an important role to explain the raise of these older shorelines to their present levels on the sea floor

late quaternary sedimentation in the strait of bosporus high resolution seismic profiling abstract uniboom profiling supported by borehole data in the southern part of the bosporus revealed that close to its banks holocene sediments are underlain by the faulted slopes of a valley cut in many places into the palaeozoic bedrock away from the banks the sediments thicken and their boundary with the underlying pleistocene deposits is defined by an erosional surface at about the 80 ms twt this surface marks the initiation of marine currents in the valley as its deeper parts began to be submerged in the late pleistocene to early holocene marine spillway phase the upward coarsening holocene sequence records the subsequent evolution of the present two way marine strait the sequence is divided into three seismostratigraphic units the lowest one constitutes an onlapping fill deposited under salt wedge estuarine conditions when sediment input and runoff discharge were high and sealevel was still rising but the flow of mediterranean waters into the black sea was not continuous it fills low areas and is well developed under a sill close to the southern entrance of the strait as sealevel rose closer to its present level and the rate of terrigenous input decreased in the middle holocene this unit began to be eroded and reworked by strong bottom currents the second unit records the transitional stage between the estuarine phase and the present two layered current system its seismic facies and sedimentary features indicate deposition under high energy conditions and shifting loci of accumulation the third surficial unit is a thin depositional lag rich in shell fragments blanketing the other two units it records deposition under fully marine conditions and flow of powerful bottom currents during the last few millenia