an active deep marine strike slip basin along the north anatolian fault in turkey the tekirdag depression within the marmara sea in the mediterranean region is an active rhomb shaped strike slip basin along the north anatolian fault with a basin floor at a water depth of 1150 m new multichannel seismic reflection data and on land geological studies indicate that the basin is forming along a releasing bend of the strike slip fault and is filled with syntransform sediments of pliocene quaternary age the basin is bounded on one side by the north anatolian fault and on the other side by a subparallel normal fault which forms the steep submarine slope in cross section the basin is strongly asymmetric with the thickness of the syntransform strata increasing from a few tens of meters on the submarine slope to over 2 5 km adjacent to the north anatolian fault seismic sections also show that the slope forming normal fault connects at depth to the north anatolian fault implying that the basin is completely detached from its substratum the whole structure can be envisaged as a huge rather flat negative flower structure the releasing bend of the north anatolian fault responsible for the formation of the basin is flanked by a constraining bend along the constraining bend the syntransform strata are being underthrust implying a recent change in the direction of the regional displacement vector this thrusting is responsible for the uplift of the submarine slope to a height of 924 m possibly by a mechanism of elastic rebound regional geology suggests that most of the syntransform strata are lacustrine with only the topmost few hundred meters consisting of deep marine clays the anomalous present depth of the tekirdag depression is due to reduced quaternary sedimentation coupled with high rates of displacement along the north anatolian fault which amounts to 20 mm yr in the marmara sea region

connection between weak stratospheric vortex events and the pacific decadal oscillation we investigate the possible impacts of the pacific decadal oscillation pdo on the occurrence of weak stratospheric polar vortex wsv events in the northern hemisphere winter wsv events which are defined when polar cap geopotential height anomalies at 50 hpa fall below the 10th percentile in winter are observed more frequently during positive pdo phases than during negative pdo phases additionally tropospheric wave forcings that drive wsv events are remarkably different between the two phases of the pdo during the positive pdo phase the vertical propagation of wavenumber one waves plays a predominant role with a rather minor contribution of wavenumber two waves this contrasts with the negative pdo phase when the wsv events are primarily caused by wavenumber two waves this difference is partly related to the pdo induced tropospheric circulation anomalies over the north pacific whose zonal wavenumber one component constructively destructively interferes with climatological planetary scale waves during positive negative pdo winters the predominant wavenumber two wave forcings during the negative pdo phase are likely related to the enhanced tropospheric eddy activity over alaska that results from the poleward shift of the pacific jet in response to the negative pdo

investigation of tsunami hydrodynamic parameters in inundation zones with different structural layouts in this study we analyze the tsunami parameter hydrodynamic demand hd using advanced numerical modeling the hd can be defined as the square of the froude number which represents the relative value of the drag force damage level of tsunami waves in the inundation zone the other key hydrodynamic parameters investigated in this study include maximum flow depth inundation depth maximum current velocity and its direction and maximum water elevation and discharge flux occurring during tsunami inundation the analyses are performed on regular shaped basins with various orientations and distribution of coastal and land structures in order to provide comparisons of the results in a number of different case studies we also provide information for defining damage levels in residential areas and for testing the performance of coastal protection structures

distribution and texture of the bottom sediments in a semi enclosed coastal inlet the izmit bay from the eastern sea of marmara turkey thirty one surficial sediment samples were collected from the floor of izmit bay with a grab onboard the rv bilim in summer 1987 and analysed for their grain size total carbonate and organic carbon distribution low calcareous terrigenous mud 2 45 caco3 with a relatively high silt percentage was the principal sediment type found on the floor of izmit bay sediments rich in sand and gravel usually occur in the narrow and shoal areas of the bay where biogenic and topography related hydrodynamic conditions are dominant factors controlling the nature of bottom deposits the carbonates are made up almost entirely of the remains of calcareous organisms organic carbon concentrations of the sediments 0 35 1 62 are probably associated with the high primary production rates in this region thus the rates of sedimentation in the izmit bay calculated from the organic carbon and primary productivity data are estimated to be up to 70 cm 1000 years

long term seismicity of istanbul and of the marmara sea region we examine the long term seismicity of the marmara sea region in turkey over a period of twenty centuries to attempt to answer two questions 1 how well recorded in history is the earthquake activity of this region and 2 does seismicity over this long period of time differ from that over the present century we study this densely populated and fast developing region because it is one of the most tectonically active regions on the continents that appears today to be relatively quiescent

observed connection between stratospheric sudden warmings and the madden julian oscillation 1 the effect of the madden julian oscillation mjo on the northern hemisphere wintertime stratospheric polar vortex and major mid winter stratospheric sudden warmings ssws is evaluated using a meteorological reanalysis dataset the mjo influences the region in the tropospheric north pacific sector that is most strongly associated with a ssw consistent with this ssws in the reanalysis record have tended to follow certain mjo phases the magnitude of the influence of the mjo on the vortex is comparable to that associated with the quasi biennial oscillation and el nino the mjo could be used to improve intra seasonal projections of the northern hemisphere high latitude circulation and in particular of the tropospheric northern annular mode at lags exceeding one month

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

sulphur and oxygen sequestration of n c37 and n c38 unsaturated ketones in an immature kerogen and the release of their carbon skeletons during early stages of thermal maturation sedimentary rock from the gessoso solfifera formation messinian in the vena del gesso basin northern italy containing immature ro 0 25 s rich organic matter was artificially matured by hydrous pyrolysis at temperatures from 160 to 330 c for 72 h to study the diagenetic fate of n c37 and n c38 di and tri unsaturated methyl and ethyl ketones alkenones biosynthesised by several prymnesiophyte algae during early diagenesis the alkenones are incorporated into the kerogen by both sulphur and oxygen cross linking as indicated by chemical degradation experiments with the kerogen of the unheated sample heating at temperatures between 160 and 260 c which still represents early stages of thermal maturation produces large amounts up to 1 mg g toc of s bound o bound and both s and o bound n c37 and n c38 skeletons saturated n c37 and n c38 methyl ethyl and mid chain ketones c37 and c38 mid chain 2 5 di n alkylthiophenes c37 and c38 1 2 di n alkylbenzenes and c37 and c38 n alkanes with increasing thermal maturation three forms of the n c37 and n c38 skeletons are relatively stable saturated hydrocarbons 1 2 di n alkylbenzenes and saturated ketones whereas the s and o bound skeletons are relatively labile these results suggest that in natural situations saturated ketones with an n c37 and n c38 skeleton can be expected as well as the corresponding hydrocarbons

crocetane a potential marker of photic zone euxinia in thermally mature sediments and crude oils of devonian age abstract crocetane an irregular c 20 isoprenoid in sediments generally associated with gas hydrate settings is a molecular indicator for the anaerobic oxidation of methane green sulfur bacteria gsb are the main source for specific aromatic carotenoids e g isorenieratane in sedimentary environments and are molecular indicators of photic zone euxinia pze the present study comprises a detailed molecular and isotopic study of crocetane and gsb derived carotenoids in devonian sediments of the western canada sedimentary basin wcsb covering a range of thermal maturities in addition a series of oils generated from devonian source rocks of the basin have been analysed for crocetane crocetane was found in ten sediments from the wcsb and in seven devonian wcsb crude oils its abundance was found to increase with thermal maturity whereas the components derived from c 40 derived carotenoids decrease steadily we were not able to identify 2 6 10 15 19 pentamethylicosane pmi neither in the duvernay formation sediments nor in the wcsb crude oils consistent with previous findings the preferred proposed natural product precursor for crocetane is thus gsb derived carotenoids this is corroborated by their similar structural features and the 13 c value of combined crocetane and phytane in these samples however contributions from other carotenoids cannot be fully excluded crocetane can provide evidence for pze conditions in highly mature samples and crude oils of devonian age

pyrolysis of kerogens in the absence and presence of montmorillonite i the generation degradation and isomerization of steranes and triterpanes at 200 and 300 c abstract the sterane and triterpane biomarker distribution obtained from extracted bitumens and kerogen pb pyrolysate bitumens of immature cretaceous black shale cbs and rocky mountain coal rmc at 200 and 300 c in the presence and absence of montmorillonite reveal that the generation release of biomarkers was more significant than isomerization at 200 c pyrolysis whereas isomerization and degradation were most important at 300 c pyrolysis montmorillonite has a pronounced catalytic effect on these reactions i e generation isomerization and degradation the ratios of c29 20 s s r steranes and c31 and c32 s s r hopanes display reversals with heating time at 200 c pyrolysis irrespective of the presence or absence of montmorillonite whereas they increased uniformly with thermal stress at 300 c pyrolysis the extent of isomerization occurring at chiral centers in ring systems and in acyclic systems are different it has been confirmed that the isomerization at the c22 and c20 position of the extended hopanes and the steranes respectively are slower than those of the hopanes and the steranes in the 300 c pyrolysis the c27 steranes increased relative to c29 steranes with heating time in the pyrolysate of the rocky mountain coal kerogen this phenomenon is more significant in the presence of montmorillonite the increase may indicate either the formation of secondary c27 steranes or the early loss of c29 steranes relative to c27 steranes in a sedimentary basin isomerization probably occurs in the bitumen and kerogen at different rates these data show that maturation indices may be reversed with depth by using the examples of 20 s s r and 22 s s r where the rate of generation of the compounds from kerogen is faster than the rate of isomerization reactions occurring in the bitumen with time and temperature

tsunamis in the sea of marmara historical documents for the past models for the future abstract more than 30 tsunami events have impacted the coasts of the sea of marmara in the past two millennium clustering in izmit bay the shores of istanbul gemlik bay the shores of the kapidag and gelibolu peninsulas with respect to the last well known tsunami the izmit tsunami of 17 august 1999 available field survey run up data and marine surveys provide an opportunity to evaluate how these events were triggered the main purpose of this study is to determine the slope failure potential as a possible tsunamigenic source in the sea of marmara by utilising multi beam bathymetry shallow and deep seismic reflection data on the basis of the landslide geomorphology the generation propagation and coastal amplifications of tsunamis related to earthquake and slope failure scenarios were tested by using tsunami simulation model two layer the maximum water surface elevations near the shores along the north and south coasts are obtained according to the selected scenarios of tsunami generation by using available data

impact of dia and catagenesis on sulphur and oxygen sequestration of biomarkers as revealed by artificial maturation of an immature sedimentary rock hydrous pyrolysis of an immature ro 0 25 sulphur rich marl from the gessoso solfifera formation messinian in the vena del gesso basin was carried out at 160 c t 330 c for 72 h to study the effect of progressive diagenesis and early catagenesis on the abundance and distribution of sulphur containing and sulphur and oxygen linked carbon skeletons in low molecular weight and high molecular weight fractions e g kerogen to this end compounds in the saturated hydrocarbon fraction monoaromatic hydrocarbon fraction polyaromatic hydrocarbon fraction alkylsulphide fraction and ketone fraction were quantified as well as compounds released after desulphurisation of the polar fraction and hilialh4 treatment of the desulphurised polar fraction sulphur bound phytane and 20r 5 14 17 h and 20r 5 14 17 h c27 c29 steranes in the polar fraction become less abundant with increasing maturation temperature whereas the amount of their corresponding hydrocarbons increases in the saturated hydrocarbon fraction carbon skeletons that are bound in the kerogen by multiple bonds e g c38n alkane and isorenieratane are first released into the polar fraction and then as free hydrocarbons these changes occur at relatively low levels of thermal maturity ro 0 6 as evidenced by the immature values of biomarker maturity parameters such as the c35 hopane ratio and the 22s 22s 22r 17 21 h c35 hopane ratio sulphur and oxygen bound moieties present in the polar fraction are not stable with increasing thermal maturation however alkylthiophenes ketones 1 2 di n alkylbenzenes and free n alkanes seem to be stable thermal degradation products of these sulphur and oxygen bound moieties thus apart from free n alkanes which are abundantly present in more mature sedimentary rocks and crude oils alkylthiophenes 1 2 di n alkylbenzenes and ketones can also be expected to occur the positions of the thiophene moiety and the carbonyl group coincide with the original positions of the functional groups of their precursors thus important information about palaeobiochemicals is retained throughout the sequestration degradation process

the active main marmara fault abstract this paper presents selections from and a synthesis of a high resolution bathymetric sparker and deep towed seismic reflection data set recently acquired by the french ifremer r v le suroit in an e w deep trough that forms the northern half of the sea of marmara in nw turkey it includes the first high resolution complete bathymetric map of this area a single throughgoing dextral strike slip fault system which is the western continuation of the northern branch of the north anatolian fault cuts this trough lengthwise and joins the 1999 8 17 kocaeli earthquake fault with the 1912 8 09 arkoy murefte earthquake fault both of which display strike slip offset in its eastern one fourth the structure follows closely the northern margin of the deep trough whereas in the west it hugs its southern margin the eastern one fourth of the structure has a minor component of its displacement distributed across the deep trough owing to a possible original bend in the course of the dextral structure the present course of the north anatolian fault in the sea of marmara originated some 2 105 a ago by cutting across the older basin fabric generated by a dominant nne ssw extension before it began taking up major motion in the pliocene

tropospheric precursors and stratospheric warmings abstractmany tropospheric arctic oscillation ao events are preceded by stratospheric ao events and even earlier in time by anomalous upward energy flux associated with rossby waves in the troposphere this study identifies lower tropospheric circulation anomalies that precede large ao events in both the troposphere and stratosphere and the anomalous upward energy flux compositing analysis of stratospheric warming events identifies regional tropospheric precursors which precede stratospheric warmings the tropospheric precursor is found to vary when compositing over polar vortex displacements and splits separately prior to vortex displacements the main anomaly sea level pressure center of the tropospheric precursor is located across northwest eurasia and is associated with the siberian high prior to vortex splits a similar anomaly center is identified in the tropospheric precursor but is weaker and appears to be more strongly related to a shift in the storm tracks differences in the sea level pressu

artificial maturation of an immature sulfur and organic matter rich limestone from the ghareb formation jordan abstract an immature r o 0 39 s rich s org c 0 07 organic matter rich 19 6 wt toc limestone from the ghareb formation upper cretaceous in jordan was artificially matured by hydrous pyrolysis 200 220 300 c 72 h to study the effect of progressive diagenesis and early catagenesis on the amounts and distributions of hydrocarbons organic sulfur compounds and s rich geomacromolecules the use of internal standards allowed the determination of absolute amounts with increasing thermal maturation large amounts of alkanes and alkylthiophenes with predominantly linear carbon skeletons are generated from the kerogen the alkylthiophene isomer distributions do not change significantly with increasing thermal maturation indicating the applicability of alkylthiophenes as biomarkers at relatively high levels of thermal maturity for a given carbon skeleton the saturated hydrocarbon alkylthiophenes and alkylbenzo b thiophenes are stable forms at relatively high temperatures whereas the alkylsulfides are not stable the large amount of alkylthiophenes produced relative to the alkanes may be explained by the large number of monosulfide links per carbon skeleton these results are in good agreement with those obtained previously for an artificial maturation series of an immature s rich sample from the gessoso solfifera formation

role of the quasi biennial oscillation in the downward extension of stratospheric northern annular mode anomalies using the jra 55 reanalysis datasets and radiosonde observations the impact of the quasi biennial oscillation qbo on the downward extension of stratospheric northern annular mode nam signals in its positive and negative phases positive and negative nam hereafter is examined the results show that the average number of days per month on which stratospheric negative nam signals extend downward into the troposphere is more than twice as large during the easterly phase of the qbo eqbo as those during the westerly phase of the qbo wqbo the increasing likelihood of downward extension of stratospheric negative nam signals during the eqbo is related to three factors enhanced upward wave 1 fluxes entering the stratosphere anomalous poleward wave fluxes below 100 hpa and eqbo induced residual circulation it is also revealed that the eqbo induced subtropical tropospheric easterly anomalies lead to positive height anomalies over the subtropical north atlantic which are amplified by transient eddies and maintained by convection these subtropical positive height anomalies further stimulate an anomalous wave train forcing subpolar positive height anomalies over the euro atlantic sector and enhancing wave 1 over the pacific the eqbo could also induce positive height anomalies in the tropical troposphere and these anomalies are related to convection and vertical motion the positive height anomalies can induce anomalous poleward propagating waves forcing negative height anomalies over the north pacific at mid high latitudes and the enhancing wave 1 fewer stratospheric positive nam signals extend downward into the troposphere during the eqbo than during the wqbo with mechanisms similar to those of negative nam

early generation characteristics of a sulfur rich monterey kerogen this paper documents the critical role of organic sulfur in the early formation of bitumen and oil from a sulfur rich kerogen from the miocene monterey formation in california monterey kerogen commonly contains abundant chemically bound sulfur 8 14 wt which appears responsible for early low temperature generation of heavy sulfur rich petroleum due to the lower energy required to break carbon sulfur bonds compared to carbon carbon bonds hydrous pyrolysis was used to simulate the natural generation of petroleum from a sulfur rich type ii kerogen from the phosphatic member of the monterey shale the amount and distribution of sulfur in the kerogen bitumen and expelled oil generated at various temperatures indicate that 1 initial bitumen and oil generation is directly related to cleavage of weak sulfur linkages and 2 most of the expelled oil is formed by decomposition of bitumen and not directly from the kerogen finally comparison of hydrous pyrolysis results with other type ii kerogens suggests that the temperature of peak bitumen generation is inversely related to the heteroatom content primarily sulfur of the kerogen low temperature bitumen generation is an important exploration concept because kerogen rich in sulfur can generate producible oil at thermal maturities significantly below conventionally accepted values furthermore established relationships between thermal maturity sulfur content and other oil properties such as api gravity can be used to rank exploration prospects

the role of minerals in the thermal alteration of organic matter iii generation of bitumen in laboratory experiments abstract a series of pyrolysis experiments utilizing two different immature kerogens from the monterey and green river formations mixed with common sedimentary minerals calcite illite or namontmorillonite was conducted to study the impact of the mineral matrix on the bitumen that was generated calcite has no significant influence on the thermal evolution of bitumen and also shows virtually no adsorption capacity for any of the pyrolysate in contrast montmorillonite and illite to a lesser extent alter bitumen during dry pyrolysis montmorillonite and illite also display strong adsorption capacities for the polar constituents of bitumen by this process hydrocarbons are substantially concentrated within the pyrolysate that is not strongly adsorbed on the clay matrices the effects of the clay minerals are significantly reduced during hydrous pyrolysis the strong adsorption capacities of montmorillonite and illite as well as their thermocatalytic properties may in part explain why light oils and gases are generated from certain argillaceous source rock assemblages whereas heavy immature oils are often derived from carbonate source rocks

tsunamis in the black sea comparison of the historical instrumental and numerical data 1 the tsunami hazard in the black sea is discussed by comparing historical instrumental data and numerical results there are 22 tsunami events in the black sea documented since the first century and nine of them have occurred in twentieth century the numerical simulations of tsunami propagation for the 1966 and 1939 events are performed by using the framework of the shallow water theory the instrumental data from tide gauge records are used to compare and validate the simulation results and estimate the wave motion at other locations where the instrumental data are unavailable the distribution of maximum positive tsunami amplitudes along the north and south coasts are obtained for each event the arrival time tsunami amplitudes and directivity of tsunamis in the black sea are studied the probable source and target areas of tsunamis are discussed

stratospheric connection to the abrupt end of the 2016 2017 iberian drought southwestern europe experienced extraordinary rainy and windy conditions in march 2018 leading to the end of the most severe drought since 1970 at continental scale this anomalous weather was linked to a persistent negative north atlantic oscillation pattern two weeks earlier a sudden stratospheric warming ssw took place preceded by the strongest planetary wave activity on record in this study we explore the connection between the ssw and the weather shift by employing a weather regime approach and flow analogues the timing of the downward propagation of the stratospheric anomalies the transition to and persistence of the negative north atlantic oscillation weather regime and the sudden precipitation increase are all consistent with the typical tropospheric state after ssws our results evidence a significant role of the 2018 ssw in the record breaking precipitation event

characteristic features of the north anatolian fault in the eastern marmara region and its tectonic evolution shallow seismic profiles are used to image the tectonic and stratigraphic setting in izmit bay eastern marmara sea four seismic units were detected in the sediments of izmit bay which carry the effects of the tectonic uplift and global sea level variations the area appears to be a negative flower structure controlled by the northern branch of the north anatolian fault in the late pliocene the north anatolian fault reached marmara sea as a master fault smallscale faults were evolved around the master fault under a regime of dextral shear the northward bending of the master fault gave rise to en echelon faults opening the sub basins in izmit bay as releasing bends the secondary faults which developed as low angle oblique to the master fault are also the products of dextral shear to the south short dextral ene wsw trending faults are interpreted as p shears while to the north dextral wnw ese trending faults represents r shears these faults absorbed the deformation at the western end of the ruptured zone during the

tropospheric precursors of anomalous northern hemisphere stratospheric polar vortices regional extratropical tropospheric variability in the north pacific and eastern europe is well correlated with variability in the northern hemisphere wintertime stratospheric polar vortex in both the ecmwf reanalysis record and in the whole atmosphere community climate model to explain this correlation the link between stratospheric vertical eliassen palm flux variability and tropospheric variability is analyzed simple reasoning shows that variability in the north pacific and eastern europe can deepen or flatten the wintertime tropospheric stationary waves and in particular its wavenumber 1 and 2 components thus providing a physical explanation for the correlation between these regions and vortex weakening these two pathways begin to weaken the upper stratospheric vortex nearly immediately with a peak influence apparent after a lag of some 20 days the influence then appears to propagate downward in time as expected from wave mean flow interaction theory these patterns are influenced by enso and october eurasian snow cover perturbations in the vortex induced by the two regions add linearly these two patterns and the quasi biennial oscillation qbo are linearly related to 40 of polar vortex variability during winter in the reanalysis record

the seismotectonics of the marmara region turkey results from a microseismic experiment the marmara region is an active tectonic zone characterised by the transition between the dextral strike slip regime of the north anatolian fault naf and the extension regime of the aegean sea strong historical earthquakes m 7 and the presence of known seismic gaps imply a high level of seismic hazard a synthesis of recent studies of active tectonics in the region is presented including inland and underwater observations the branching of the naf is explained in terms of increasing influence of the extension historical information and instrumental seismicity are reinterpreted in order to have a critical appraisal of the existence of large seismic gaps in the central and eastern marmara sea focal mechanisms of strong earthquakes are used to obtain orientation and shape factor of the deviator of the stress tensor the resulting tensor is in shear regime s 2 vertical but close to extension r 0 93 with s 1 oriented n145 0 a microseismic experiment with 48 stations distributed around the marmara sea was carried out in october december 1995 a total of 137 microearthquakes were located and 23 of those were selected to obtain focal mechanism solutions the epicentral distribution indicates activity along the system of pull apart basins north of the marmara sea the segment between marmara sea and the saros bay activated in 1912 and the gulf of izmit site of the 1754 earthquake are now silent seismic activity is very linear along the northern branch of the naf but it is more divused on the bursa and iznik branches southeast of the marmara sea the stress tensor obtained from the focal mechanisms of the micro earthquakes is compared to the one inverted from teleseismic data the microseismic stress is compatible with a shear intermediate regime like the one obtained from strong earthquakes though not as well constrained one of the acceptable solutions having the same orientation but diverent shape r 0 5 2000 elsevier science b v all rights reserved

downward migration of extratropical zonal wind anomalies 1 we show in confirmation of previous work using one and three dimensional models that extratropical zonal wind anomalies produced by fluctuating rossby wave forcing in the troposphere appear first in the stratosphere and migrate downward into the troposphere by systematically eliminating wave reflection and downward control through an induced meridional circulation it is shown that the downward migration is dependent on neither process rather the mechanism appears to rely on local wave mean flow interaction just as in the similar downward migration evident in the tropical quasi biennial oscillation in particular these results imply that the similar downward migration observed in the arctic oscillation should not be taken to indicate any controlling influence of the stratosphere on the troposphere

the role of minerals in the thermal alteration of organic matter iv generation of n alkanes acyclic isoprenoids and alkenes in laboratory experiments a series of pyrolysis experiments utilizing two different immature oil prone kerogens type i green river formation kerogen type ii monterey formation kerogen mixed with common sedimentary minerals calcite illite or na montmorillonite was conducted to study the effects of minerals on the generation of n alkanes acyclic isoprenoids and alkenes during laboratory simulated catagenesis of kerogen the influence of clay minerals on the aliphatic hydrocarbons is critically dependent on the water concentration during laboratory thermal maturation under extremely low contents of water i e dry pyrolysis where only pyrolysate water is present c12 range n alkanes and acyclic isoprenoids are mostly destroyed by montmorillonite but undergo only minor alteration with illite both clay minerals significantly reduce alkene formation during dry pyrolysis under hydrous conditions mineralwater 2 1 the effects of the clay minerals are substantially reduced in addition the dry pyrolysis experiments show that illite and montmorillonite preferentially retain large amounts of the polar constituents of bitumen but not n alkanes or acyclic isoprenoids therefore bitumen fractionation according to polarity differences occurs in the presence of these clay minerals by this process n alkanes and acyclic isoprenoids are concentrated in the bitumen fraction that is not strongly adsorbed on the clay matrices the extent of these concentration effects is greatly diminished during hydrous pyrolysis in contrast calcite has no significant influence on the thermal evolution of the hydrocarbons in addition calcite is incapable of retaining bitumen therefore the fractionation of n alkanes or acyclic isoprenoids relative to the polar constituents of bitumen is insignificant in the presence of calcite

the stratopause evolution during different types of sudden stratospheric warming event recent work has shown that the vertical structure of the arctic polar vortex during different types of sudden stratospheric warming ssw events can be very distinctive specifically ssws can be classified into polar vortex displacement events or polar vortex splitting events this paper aims to study the arctic stratosphere during such events with a focus on the stratopause using the modern era restrospective analysis for research and applications reanalysis data set the reanalysis dataset is compared against two independent satellite reconstructions for validation purposes during vortex displacement events the stratopause temperature and pressure exhibit a wave 1 structure and are in quadrature whereas during vortex splitting events they exhibit a wave 2 structure for both types of ssw the temperature anomalies at the stratopause are shown to be generated by ageostrophic vertical motions transformed eulerian mean diagnostics are used to show differences in the planetary wave activity between displacement and splitting events the convergence of eliassen palm flux which leads to ssws is longer for displacement events and a persistent mesospheric eliassen palm flux divergence can be observed about 20 days after displacement events finally although this work focuses on the stratopause at high latitudes associated observations of the equatorial middle atmosphere are also examined to explore links between the equator and polar evolution during ssws

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

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

northern hemisphere mid winter vortex displacement and vortex split stratospheric sudden warmings influence of the madden julian oscillation and quasi biennial oscillation we investigate the connection between the equatorial madden julian oscillation mjo and different types of the northern hemisphere mid winter major stratospheric sudden warmings ssws i e vortex displacement and vortex split ssws the mjo ssw relationship for vortex split ssws is stronger than that for vortex displacement ssws as a result of the stronger and more coherent eastward propagating mjos before vortex split ssws than those before vortex displacement ssws composite analysis indicates that both the intensity and propagation features of mjo may influence the mjo related circulation pattern at high latitudes and the type of ssws a pronounced quasi biennial oscillation qbo dependence is found for vortex displacement and vortex split ssws with vortex displacement split ssws occurring preferentially in easterly westerly qbo phases the lagged composites suggest that the mjo related anomalies in the arctic are very likely initiated when the mjo related convection is active over the equatorial indian ocean around the mjo phase 3 further analysis suggests that the qbo may modulate the mjo related wave disturbances via its influence on the upper tropospheric subtropical jet as a result the mjo related circulation pattern in the arctic tends to be wave number one wave number two 25 30 days following phase 3 i e approximately phases 7 8 when the mjo related convection is active over the western pacific during easterly westerly qbo phases which resembles the circulation pattern associated with vortex displacement vortex split ssws

propagation of the arctic oscillation from the stratosphere to the troposphere geopotential anomalies ranging from the earth s surface to the middle stratosphere in the northern hemisphere are dominated by a mode of variability known as the arctic oscillation ao the ao is represented herein by the leading mode the first empirical orthogonal function of low frequency variability of wintertime geopotential between 1000 and 10 hpa in the middle stratosphere the signature of the ao is a nearly zonally symmetric pattern representing a strong or weak polar vortex at 1000 hpa the ao is similar to the north atlantic oscillation but with more zonal symmetry especially at high latitudes in zonal mean zonal wind the ao is seen as a north south dipole centered on 40 45 n in zonal mean temperature it is seen as a deep warm or cold polar anomaly from the upper troposphere to 10 hpa the association of the ao pattern in the troposphere with modulation of the strength of the stratospheric polar vortex provides perhaps the best measure of coupling between the stratosphere and the troposphere by examining separately time series of ao signatures at tropospheric and stratospheric levels it is shown that ao anomalies typically appear first in the stratosphere and propagate downward the midwinter correlation between the 90 day low pass filtered 10 hpa anomaly and the 1000 hpa anomaly exceeds 0 65 when the surface anomaly time series is lagged by about three weeks the tropospheric signature of the ao anomaly is characterized by substantial changes to the storm tracks and strength of the midtropospheric flow especially over the north atlantic and europe the implications of large stratospheric anomalies as precursors to changes in tropospheric weather patterns are discussed

the role of the siberian high in northern hemisphere climate variability the dominant mode of sea level pressure slp variability during the winter months in the northern hemisphere nh is characterized by a dipole with one anomaly center covering the arctic with the opposite sign anomaly stretched across the mid latitudes associated with the slp anomaly is a surface temperature anomaly induced by the anomalous circulation we will show that this anomaly pattern originates in the early fall on a much more regional scale in siberia as the season progresses this anomaly pattern propagates and amplifies to dominate much of the extratropical nh making the siberian high a dominant force in nh climate variability in winter also since the slp and surface temperature anomalies originate in a region of maximum fall snow cover variability we argue that snow cover partially forces the phase of winter variability and can potentially be used for the skillful prediction of winter climate

role of eurasian snow cover in wintertime circulation decadal simulations forced with satellite observations 1 we investigate the impact of the eurasian snow cover extent on the northern hemisphere winter circulation by performing a suite of ensemble simulations with the meteo france arpege climat atmospheric general circulation model spanning 2 decades 1979 2000 observed snow cover derived from satellite infrared and visible imagery has been forced weekly into the model variability in autumn early winter snow cover extent over eastern eurasia is linked to circulation anomalies over the north pacific that are influencing the north atlantic sector in late winter through the development of the aleutian icelandic low seesaw teleconnection the forcing of realistic snow cover in the model augments potential predictability over eastern eurasia and the north pacific and improves the hindcast skill score of the aleutian icelandic low seesaw teleconnection enhanced eastern eurasia snow cover is associated with an anomalous upper tropospheric wave train across eurasia anomalously high upward wave activity flux and a displaced stratospheric polar vortex

from phytoplankton to oil shale reservoirs a 19 million year record of the late cretaceous tethyan upwelling regime in the levant basin abstract the complexity of sedimentary organic matter formation its source to burial and influence on bottom water communities are addressed in this study of the 19 million years long upper cretaceous tethyan upwelling regime in the levant a multi proxy approach is amalgamated into a model through which the paleoceanographic complexity of an intense and long lasting upwelling system is better understood a shift in primary producer assemblages and reorganization of the bottom water bacterial consortium followed the campanian maastrichtian boundary enforcing conspicuous sedimentological and faunal changes the siliceous and phosphatic bearing sediments of the campanian gave way to maastrichtian uniform and regionally distributed organic rich carbonates accompanied by an increase in sedimentation rates from 1 to 6 cm kyr this has facilitated both the increase in organic matter production and its excellent preservation and through diagenetic pathways affected its elemental composition these paleoceanographic modifications have also affected foraminiferal assemblages from massive blooms of triserial buliminid benthic foraminifera during the campanian which have sequestered diatom chloroplasts to diverse trochospiral forms during the maastrichtian using nitrate instead of oxygen for their respiratory pathways we propose that shifts in the type of primary producers promote a change in the amount and type of preserved organic matter in bottom water communities on the lithological composition of the rock mass and ultimately on the hydrocarbon generation potential of the studied source rock the continued rise of southern tethyan sea level and global highstands during the upper maastrichtian culminating into arabian plate wide maximum flooding surfaces cause the migration of upwelling activity away from the study area terminating the high productivity sequence in the levant

introduction to tsunami science ten years after the 2004 indian ocean tsunami volume i twenty papers on the study of tsunamis and respective tsunamigenic earthquakes are included in volume ii of the pageoph topical issue tsunami science ten years after the 2004 indian ocean tsunami the papers presented in this second of two special volumes of pure and applied geophysics reflect the state of tsunami science during this time including five papers devoted to new findings specifically in the indian ocean two papers compile results from global observations and eight papers cover pacific ocean studies focusing mainly on the 2011 tohoku earthquake and tsunami remaining papers in this volume describe studies in the atlantic ocean and mediterranean sea and tsunami source studies overall the volume not only addresses the pivotal 2004 indian ocean and 2011 tohoku tsunamis but also examines the tsunami hazard posed to other critical coasts in the world

diagenetic and detrital origin of moretane anomalies through the permian triassic boundary abstract many biogeochemical anomalies coincide with the late permian extinction lpe 252 28 ma several mechanisms have been proposed to explain the moretane hopane anomaly that has been identified in samples from meishan gssp section in southeastern china here we report homohopane 2 and 3 methylhomohopane and lithological data for a drill core from the meishan section in southeastern china three intervals of elevated c 30 moretane hopane ratios are recorded in the lungtan yinkeng and helongshan formations moretane hopane ratios of c 31 34 homohopanes and the 2 and 3 methylhomohopanes display the same stratigraphic patterns as the c 30 moretane hopane record in light of the multiple and parallel moretane anomalies for the homohopane and 2 and 3 methylhomohopane series enhanced input from higher plant organic matter such as coal and peat does not adequately explain the observed isomer patterns correlation of high moretane hopane ratios with low c 35 homohopane index hhi and high hopane sterane values suggest increased input of hopanoids from oxic soils additionally moretane hopane ratios show excellent correlations with total clay percentages and specific clay types particularly chlorite illite and mixed layer illite smectite we conclude that a combination of episodic hopanoid input from soil bacteria and diagenetic effects related to redox and detrital clays generated the unique moretane hopane patterns at meishan similar relationships of ts ts tm with redox source indicators and lithology indicate that ts ts tm is affected by the same factors controlling the moretane hopane ratios berthierine a clay that requires reducing conditions for formation was detected in samples from the lungtan formation we are unable to determine from our results whether the berthierine is authigenic or detrital but future determination of the origin of berthierine at meishan may offer additional environmental insight no link between diasteranes and lithology was observed in this study suggesting that diasteranes are relatively unaffected by the detrital clay component of the meishan sediments in total the results point toward the complex role of source input lithology and depositional redox conditions in the transformation of organic matter during maturation future work is required to elucidate the lithological effects on diagenetic processes including biomarker genesis isomerization and thermal degradation

erratum to origin of the strait of canakkale dardanelles regional tectonics and the mediterranean marmara incursion marine geology 164 2000 139 156

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

a unified source model for the 2011 tohoku earthquake abstract the devastating 2011 tohoku earthquake was observed by dense networks of geophysical instruments a unified source model was constructed through joint inversion of teleseismic strong motion and geodetic datasets the result indicates that the earthquake consists of three main ruptures after small rupture in the initial 50 s the first rupture expanded at a slow speed of 1 8 km s to the northeast and east the second rupture began 20 s later at the slowest speed of 1 5 km s and became dominant with the largest slip of 36 m the third rupture then played the leading role propagating southward at a speed of 2 5 km s only the tsunami inversion requires an extension of the source fault to a shallow part between the first rupture area and the japan trench recovering tsunamigenic slips larger than 40 m the slow rupture speed and tsunamigenic slips can explain the features of the disaster by the earthquake

enso teleconnection to the isopycnal depth fluctuations of the east japan sea intermediate water in the ulleung basin during 1968 2002 abstractthis study first detects the decadal variability in the depths of the east japan sea ejs intermediate water esiw using in situ observations and relates it to strong el nino southern oscillations ensos using multitaper cross spectrum and cyclostationary empirical orthogonal function analysis this study found significant coherences at the 99 confidence level and opposite phases between nino 3 and the esiw isopycnal depths in the ulleung basin ub at a period of 14 1 yr during 1968 2002 this suggests a teleconnection between strong ensos and the esiw the cause of which is explored when a strong el nino en develops the pacific north american pattern is intensified by the en related rossby wave interfering constructively with the climatological stationary wave the amplified wave propagates upward into the stratosphere and breaks weakening the polar vortex the en related geopotential height increases over the pole with poleward converging air and decreases over the yakutsk basin yb

blocking precursors to stratospheric sudden warming events 1 the primary causes for the onset of major midwinter stratospheric sudden warming events remain unclear in this paper we report that 25 of the 27 events objectively identified in the era 40 dataset for the period 1957 2001 are preceded by blocking patterns in the troposphere the spatial characteristics of tropospheric blocks prior to sudden warming events are strongly correlated with the type of sudden warming event that follows vortex displacement events are nearly always preceded by blocking over the atlantic basin only whereas vortex splitting events are preceded by blocking events occurring in the pacific basin or in both basins contemporaneously the differences in the geographical blocking distribution prior to sudden warming events are mirrored in the patterns of planetary waves that are responsible for producing events of either type the evidence presented here suggests that tropospheric blocking plays an important role in determining the onset and the type of warmings

on the three dimensional propagation of stationary waves abstract a locally applicable nonzonally averaged conservation relation is derived for quasi geostrophic stationary waves on a zonal flow a generalization of the eliassen palm relation the flux which appears in this relation constitutes it is argued a useful diagnostic of the three dimensional propagation of stationary wave activity this is illustrated by application to a simple theoretical model of a forced rossby wave train and to a northern hemisphere winter climatology results of the latter procedure suggest that the major forcing of the stationary wave field derives from the orographic effects of the tibetan plateau and from nonorographic effects diabatic heating and or interaction with transient eddies in the western north atlantic and north pacific oceans and siberia no evidence is found in the data for wave trains of tropical origin forcing by the orographic effects of the rocky mountains seems to be of secondary importance

why might stratospheric sudden warmings occur with similar frequency in el nino and la nina winters 1 the effect of el nino southern oscillation enso on the frequency and character of northern hemisphere major mid winter stratospheric sudden warmings ssws is evaluated using a meteorological reanalysis data set and comprehensive chemistry climate models there is an apparent inconsistency between the impact of opposite phases of enso on the seasonal mean vortex and on ssws el nino leads to an anomalously warm and la nina leads to an anomalously cool seasonal mean polar stratospheric state but both phases of enso lead to an increased ssw frequency a resolution to this apparent paradox is here proposed the region in the north pacific most strongly associated with precursors of ssws is not strongly influenced by el nino and la nina teleconnections in the observational record both la nina and el nino lead to similar anomalies in the region associated with precursors of ssws and consistent with this there is a similar ssw frequency in la nina and el nino winters a similar correspondence between the penetration of enso teleconnections into the ssw precursor region and ssw frequency is found in the comprehensive chemistry climate models the inability of some of the models to capture the observed relationship between la nina and ssw frequency appears related to whether the modeled enso teleconnections result in extreme anomalies in the region most closely associated with ssws finally it is confirmed that the seasonal mean polar vortex response to enso is only weakly related to the relative frequency of ssws during el nino and la nina

effects of continental scale snow albedo anomalies on the wintertime arctic oscillation the ncar cam3 gcm with prescribed satellite based snow albedo sa is used to investigate the remote effects of snow cover on northern hemisphere nh winter climate a pair of 100 ensemble member experiments are integrated through the autumn winter season with prescribed high and low sa over eurasia ea similar to other non cam gcm studies using prescribed snow mass anomalous ea snow albedo produces a wave activity pulse that propagates into the stratosphere culminating in a negative phase arctic oscillation ao like surface response this occurs for idealized but representative sa anomalies as well as for more realistic sa anomalies similar experiments over north america na and the entire nh are also performed unlike prior studies anomalous na snow yields a significant ao signal here the local na surface cooling elicits a transient eddy response which propagates downstream to eurasia resulting in significant but short lived cooling and upward propagating wave activity over siberia a negative ao like response develops primarily confined to the stratosphere upper troposphere which eventually gives way to a tropospheric ao like response of the opposite phase due to equatorward wave refraction and wave divergence reanalysis data support this na snow positive ao response snow forcing experiments for the whole nh however yield a weakened ao signal this is due to a muted wavenumber 1 and 2 response caused by destructive interference between the background stationary wave and the corresponding rossby wave response which results in negligible wave activity reaching the stratosphere

are the north atlantic oscillation and the northern annular mode distinguishable this study addresses the question of whether persistent events of the north atlantic oscillation nao and the northern annular mode nam teleconnection patterns are distinguishable from each other standard daily index time series are used to specify the amplitude of the nao and nam patterns the above question is examined with composites of sea level pressure and 300 and 40 hpa streamfunction along with tests of field significance a null hypothesis is specified that the nao and nam persistent events are indistinguishable this null hypothesis is evaluated by calculating the difference between time averaged nao and nam composites it is found that the null hypothesis cannot be rejected even at the 80 confidence level the wave breaking characteristics during the nam life cycle are also examined both the positive and negative nam phases yield the same wave breaking properties as those for the nao the results suggest that not only are the nao and nam persistent events indistinguishable but that the nao nam events are neither confined to the north atlantic nor are they annular

observed and simulated precursors of stratospheric polar vortex anomalies in the northern hemisphere the northern hemisphere stratospheric polar vortex is linked to surface weather after stratospheric sudden warmings in winter the tropospheric circulation is often nudged towards the negative phase of the northern annular mode nam and the north atlantic oscillation nao a strong stratospheric vortex is often associated with subsequent positive nam nao conditions for stratosphere troposphere associations to be useful for forecasting purposes it is crucial that changes to the stratospheric vortex can be understood and predicted recent studies have proposed that there exist tropospheric precursors to anomalous vortex events in the stratosphere and that these precursors may be understood by considering the relationship between stationary wave patterns and regional variability another important factor is the extent to which the inherent variability of the stratosphere in an atmospheric model influences its ability to simulate stratosphere troposphere links here we examine the lower stratosphere variability in 300 year pre industrial control integrations from 13 coupled climate models we show that robust precursors to stratospheric polar vortex anomalies are evident across the multi model ensemble the most significant tropospheric component of these precursors consists of a height anomaly dipole across northern eurasia and large anomalies in upward stationary wave fluxes in the lower stratosphere over the continent the strength of the stratospheric variability in the models was found to depend on the variability of the upward stationary wave fluxes and the amplitude of the stationary waves

eurasian snow cover variability and northern hemisphere climate predictability we present observational evidence demonstrating dynamic interactions and feedbacks between multi seasonal snow cover and winter time circulation anomalies over mid high latitudes the cooling effect of snow cover is associated with a strengthened and more expansive siberian high with more frequent topographically constrained intrusions west and north early season snow cover variability leads to altered general circulation patterns consistent with the dominant mode of winter variability observed in the northern hemisphere troposphere the implications of the surface atmosphere coupling for seasonal to interannual predictability are also discussed

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

investigation of hydrodynamic parameters and the effects of breakwaters during the 2011 great east japan tsunami in kamaishi bay the march 2011 great east japan tsunami was one of the most disastrous tsunami events on record affecting the east coast of japan to an extreme degree extensive currents combined with flow depths in inundation zones account for this devastating impact video footage taken by the eyewitnesses reveals the destructive effect and dragging capability of strong tsunami currents along the coast this study provides a numerical modeling study in kamaishi bay calculating the damage inflicted by tsunami waves on structures and coastlines in terms of the square of the froude number fr2 and also other calculated hydrodynamic parameters such as the distribution of instantaneous flow depths maximum currents and water surface elevations that occurred during this catastrophic tsunami analyses were performed by using the tsunami numerical modeling code nami dance with nested domains at a higher resolution the effect of the kamaishi breakwater on the tsunami inundation distance and coastal damage was tested by using the conditions of with breakwater without breakwater and damaged breakwater results show that the difference between the hydrostatic pressure on the seaward side of the breakwater and the leeward side of the breakwater is quite high clarifying conditions contributing to failure of the breakwater lower water surface elevations were calculated in the case of a breakwater existing at the entrance a partly valid condition for the damaged breakwater case the results are different for current velocities and fr hbox max 2 in the with breakwater condition due to the concentration of energy through the breakwater gaps

trends in thermal maturity indicators for the organic sulfur rich eagle ford shale abstract thermal maturity is critical to evaluate petroleum systems and to interpret biomarker results for paleoenvironmental and geobiology studies many thermal maturity indices were developed for marine source rocks containing type ii kerogen but their behavior in organic sulfur rich source rocks requires more investigation here we present geochemical analyses of whole and extracted rock isolated kerogen and extractable organic matter across a natural thermal maturity sequence of the upper cretaceous eagle ford shale to evaluate the behavior of maturity parameters in organic sulfur rich source rocks the samples have similar mineralogy and trace element composition minimizing potential facies effects on thermal maturity parameters atomic h c ratios of isolated kerogen extractable organic matter yield and programmed pyrolysis results show that the samples range from the pre oil through dry gas generation windows programmed pyrolysis data and kerogen elemental ratios show that the immature samples host both type iis atomic sorg c 0 04 and sulfur rich type ii kerogen kerogen sorg c 0 03 0 04 while samples with lower kerogen sorg c ratios kerogen sorg c

does the arctic stratospheric polar vortex exhibit signs of preconditioning prior to sudden stratospheric warmings abstractcharacteristics of the arctic stratospheric polar vortex are examined using reanalysis data with dynamic time warping dtw and a clustering technique to determine whether the polar vortex

molecular parameters of maturation in the toarcian shales paris basin france iv laboratory thermal alteration studies abstract an immature toarcian shale from the paris basin semecourt reported maximum burial depth 700m was heated in the laboratory under reduced pressure at different temperatures 201 257 285 c for different times 6 91 days we measured in the resulting extracts by gas chromatography or combined gas chromatography mass spectrometry 1 a extent of configuational isomerisation at i c 6 and c 10 in pristane ii c 20 and c 14 and c 17 in 5 h 14 h 17 h steranes iii c 17 and c 22 in hopanes 2 b extent of aromatisation in aromatic steroid hydrocarbons both configurational isomerisation and aromatisation occur during heating but the latter process is accelerated relative to the former in comparison with the maturation effect experienced by the toarcian shales as a result of burial depth and the associated temperature rise the results suggest that it may be possible to distinguish the thermal histories of sedimentary sequences by comparison of the relative extents of isomerisation at c 20 in steranes with the extent of aromatisation in aromatic steroid hydrocarbons

do split and displacement sudden stratospheric warmings have different annular mode signatures sudden stratospheric warmings ssws contribute to intraseasonal tropospheric forecasting skill due to their surface impacts recent studies suggest these impacts depend upon whether the polar vortex splits or is displaced during the ssw we analyse the annular mode signatures of ssws in a 1000 year ipsl cm5a lr simulation although small differences in the mean surface northern annular mode nam index following splits and displacements are found the sign is not consistent for two independent ssw algorithms and over 50 events are required to distinguish the responses we use the winter time correlation between extratropical lower stratospheric wind anomalies and the surface nam index as a metric for two way stratosphere troposphere coupling and find that the differences between splits and displacements and between classification methodologies can be simply understood in terms of their mean stratospheric wind anomalies predictability studies should therefore focus on understanding the factors that determine the persistence of these anomalies following ssws

time and space distribution of coseismic slip of the 2011 tohoku earthquake as inferred from tsunami waveform data a multiple time window inversion of 53 high sampling tsunami waveforms on ocean bottom pressure global positioning system coastal wave and tide gauges shows a temporal and spatial slip distribution during the 2011 tohoku earthquake the fault rupture started near the hypocenter and propagated into both deep and shallow parts of the plate interface a very large slip approximately 25 m in the deep part off miyagi at a location similar to the previous 869 jogan earthquake model was responsible for the initial rise of tsunami waveforms and the recorded tsunami inundation in the sendai and ishinomaki plains a huge slip up to 69 m occurred in the shallow part near the trench axis 3 min after the rupture initiation this delayed shallow rupture extended for 400 km with more than a 10 m slip at a location similar to the 1896 sanriku tsunami earthquake and was responsible for the peak amplitudes of the tsunami waveforms and the maximum tsunami heights measured on the northern sanriku coast 100 km north of the largest slip the average slip on the entire fault was 9 5 m and the total seismic moment was 4 2 1022 n m m w 9 0 the large horizontal displacement of seafloor slope was responsible for 20 40 of tsunami amplitudes the 2011 deep slip alone could reproduce the distribution of the 869 tsunami deposits indicating that the 869 jogan earthquake source could be similar to the 2011 earthquake at least in the deep plate interface the large tsunami at the fukushima nuclear power station is due to either the combination of a deep and shallow slip or a triggering of a shallow slip by a deep slip which was not accounted for in the previous tsunami hazard assessments online material table of estimated slip for all subfaults at 0 5 min invervals

active faults and evolving strike slip basins in the marmara sea northwest turkey a multichannel seismic reflection study abstract the north anatolian fault is a 1200 km long transform fault forming the boundary between the anatolian and eurasian plates near its western end it strikes through the marmara sea and is responsible for the creation of three deep marine depressions the north anatolian fault system and the linked basins in the eastern marmara sea were studied using newly acquired multi channel seismic reflection data in the marmara sea the north anatolian fault consists of a main strand and a few subsidiary branches the main strand is made up of the ganos 15 km long central marmara 105 km and north boundary 45 km fault segments the north boundary fault joins in the east to the izmit segment which was ruptured during the m s 7 4 earthquake on 17 8 1999 the north boundary fault is highly oblique to the regional displacement vector which results in the generation of a symmetrical fault wedge basin this cinarcik basin is a wedge shaped deep marine depression south of istanbul it is about 50 km long up to 20 km wide and 1250 m deep and is filled with pliocene to quaternary sediments over 3 km thick the north boundary fault joins in the west to the transpressional central marmara fault around the restraining segment boundary the syntransform sediments are being deformed into a large anticlinorium the cinarcik basin started to form when the westward propagating north anatolian fault intersected a northwest trending pre existing fault zone during the pliocene and bifurcated into nw and sw trending segments forming a transform transform transform type triple junction dextral strike slip movement along the arms of the triple junction led to the development of the cinarcik basin the present fault geometry in the marmara region was achieved later during the mid pliocene following the termination of the triple junction geometry south of the main north anatolian fault system there is a second active strike slip fault in the marmara sea made up of several segments a highly asymmetrical fault bend basin comprising pliocene quaternary sediments over 2 5 km thick is forming along a releasing fault segment of this south boundary fault system

introducing sub seasonal spatial and temporal resolution to winter climate prediction 1 the dominant northern hemisphere winter mode of variability is characterized by a same signed sea level pressure anomaly at high latitudes with an opposite signed anomaly stretching across mid latitudes the surface temperature pattern associated with this mode is a same signed temperature anomaly across the major continents and an opposite signed anomaly across the major oceans we demonstrate that this temperature pattern is mostly an artifact of multi year averaging which results in the super positioning of two distinctive patterns separation of the two patterns allows for more accurate seasonal predictions and introduces a spatial and temporal resolution in forecasts previously not possible

steranes and triterpanes generated from kerogen pyrolysis in the absence and presence of minerals abstract steranes and triterpanes generated from pyrolysis of immature monterey formation kerogen in the presence and absence of calcite illite and montmorillonite reveal results that are both consistent and divergent with published data that reflect the use of these biological markers as maturation indicators the extent of isomerization of biomarkers generated from pyrolysis of kerogen at 300 c for 2 hours at c 20 in 14 h 17 h steranes at c 22 in 17 h 21 h hopanes and of 17 h 21 h hopanes correspond to early diagenetic stages in rock extracts from sedimentary basins isomerization increases with heating time and after 1000 hours attains values which correspond to the catagenetic stage in sedimentary basins or equivalent to that of mature oil stepwise pyrolysis of the kerogen indicates faster isomerization rates for steranes and triterpanes in the bitumen than for those retained in the kerogen structure confirming earlier studies presence of a mineral matrix can influence the isomerization of steranes and triterpanes considerably comparisons with results from kerogen heated alone for a given maturation stage show that calcite inhibits illite catalyzes slightly and montmorillonite has a pronounced catalytic effect on these reactions this effect results in early isomerization of steranes and hopanes corresponding to the catagenetic stage in the presence of montmorillonite while kerogen or kerogen with calcite held at the same temperature 300 c and time 10 hours only yield isomerized products which correspond to a diagenetic stage further illite and montmorillonite affect various isomerization reactions differently the fastest reaction is the isomerization at c 20 in 14 h 17 h steranes followed by that at c 22 in 17 h 21 h hopanes and the slowest is the formation of 14 h 17 h steranes these results show that maturation measurements of rock or oil samples from sedimentary basins which use biological markers have to take into account the mineral matrix effects which have been largely ignored until present

biomarker generation from type ii s kerogens in claystone and limestone during hydrous and anhydrous pyrolysis abstract a claystone and a limestone containing immature type ii s kerogen were thermally matured in the presence and absence of water to study the influence of water and clay minerals on the generation of biomarkers in contrast to hydrous pyrolysis anhydrous pyrolysis of the claystone did not generate biomarkers which resulted in the loss of important information desulfurization of the polar fraction of the claystone showed that anhydrous pyrolysis is not capable of converting s bound biomarkers to free biomarkers for the limestone the differences between hydrous and anhydrous pyrolysis are less dramatic adsorption of the polar fraction of the claystone to smectite interlayers probably leads to cross linking reactions preventing the generation of free biomarkers during hydrous pyrolysis the smectite interlayers are occupied by water so that generation of biomarkers can take place in addition cross linking reactions during anhydrous pyrolysis of the claystone may be enhanced because of the presence of s s bonds in the organic matter of the claystone these results show that water is important in closed system laboratory experiments designed to simulate natural maturation of sedimentary organic matter

tsunamigenic sea floor deformations in addition to the primary damage they do earthquakes can cause tsunamis massive ocean swells that can inundate coastal regions in their perspective synolakis et al describe results presented at a workshop on the interface between seismology and tsunami hydrodynamics held in santa monica in may 1997 the authors discuss the highlights of the meeting and summarize future directions for research

heightened odds of large earthquakes near istanbul an interaction based probability calculation we calculate the probability of strong shaking in istanbul an urban center of 10 million people from the description of earthquakes on the north anatolian fault system in the marmara sea during the past 500 years and test the resulting catalog against the frequency of damage in istanbul during the preceding millennium departing from current practice we include the time dependent effect of stress transferred by the 1999 moment magnitude m 7 4 izmit earthquake to faults nearer to istanbul we find a 62 15 probability one standard deviation of strong shaking during the next 30 years and 32 12 during the next decade

the role of linear interference in the annular mode response to extratropical surface forcing abstract the classical problem of predicting the atmospheric circulation response to extratropical surface forcing is revisited in the context of the observed connection between autumnal snow cover anomalies over siberia and wintertime anomalies of the northern annular mode nam previous work has shown that in general circulation model gcm simulations in which autumnal siberian snow forcing is prescribed a vertically propagating rossby wave train is generated that propagates into the stratosphere drives dynamical stratospheric warming and induces a negative nam response that couples to the troposphere important questions remain regarding the dynamics of the response to this surface cooling it is shown that previously unexplained aspects of the evolution of the response in a comprehensive gcm can be explained by examining the time evolution of the phasing and hence the linear interference between the rossby wave response and the background climatological stationary wave when the wave response a

sensitivity study of hydrodynamic parameters during numerical simulations of tsunami inundation this paper describes the analysis of a parameter hydrodynamic demand which can be used to represent the potential for tsunami drag force related damage to structures along coastlines it is derived from the ratio of drag force to hydrostatic force caused by a tsunami on the structure it varies according to the instantaneous values of the current velocities and flow depths during a tsunami inundation to examine the effects of a tsunami in the present study the analyses were performed using the tsunami numerical model in two altered regular shaped basins having different bottom slopes the simulations were implemented using a single sinusoidal wave with particular initial conditions such as leading elevation wave and leading depression wave profiles with different wave periods two different initial wave amplitudes were employed to assess the diversity in the distribution of the square of the froude number fr 2 along the coastline the numerical results were compared quantitatively

the role of linear interference in northern annular mode variability associated with eurasian snow cover extent one of the outstanding questions regarding the observed relationship between october eurasian snow cover anomalies and the boreal winter northern annular mode nam is what causes the multiple week lag between positive eurasian snow cover anomalies in october and the associated peak in rossby wave activity flux from the troposphere tothe stratospherein december thisstudy exploresthe following hypothesis about thislag in order toachieve amplificationofthe waveactivity the vertically propagatingrossbywave train associated with the snow cover anomaly must reinforce the climatological stationary wave which corresponds to constructive linear interference between the anomalous wave and the climatological wave it is shown that the lag in peak waveactivityflux arisesbecause the rossby wave train associatedwiththe snowcover isin quadrature orout of phasewiththeclimatologicalstationarywavefromoctobertomid november beginninginmid novemberthe associated wave anomaly migrates into a position that is in phase with the climatological wave leading to constructive interference and anomalously positive upward wave activity fluxes until mid january climate models from the coupled model intercomparison project 3 cmip3 do not capture this behavior this linear interferenceeffectisnot onlyassociatedwith stratospheric variabilityrelatedtoeurasiansnowcoveranomalies but is a general feature of northern hemisphere troposphere stratosphere interactions and in particular dominated the negative nam events of the fall winter of 2009 10

tsunamis within the eastern santa barbara channel several locally generated tsunamis have been reported in southern california during the past 200 years yet the hazard from locally generated tsunamis has received considerably little attention we consider here tsunamis generated by coseismic displacements on the channel islands thrust cit system as well as waves generated by slope failures along the walls of the santa barbara channel we find that purely tectonic sources could generate regional tsunamis with 2m runup whereas combinations of tectonic sources and submarine mass movements could generate local runup as large as 15m