two phytoplankton blooms near luzon strait generated by lingering typhoon parma two phytoplankton blooms near luzon strait triggered by typhoon parma in 2009 were investigated using remote sensing data and in situ observations parma was slow moving a translation speed of similar to 2ms 1 and relatively weak a maximum sustained wind of similar to 30ms 1 during its lingering path northwest of luzon island after it reached a point 120 5 degrees e 20 3 degrees n west of luzon strait parma turned sharply back toward the northern philippines along approximately the same course such long similar to 7days lingering typhoons are rather rare in the south china sea scs before parma low chl a concentrations 0 6mgm 3 appeared west of the central luzon strait a nearshore phytoplankton increase was also observed north of luzon island together with high cdom color dissolved organic matter during and after the typhoon sea surface cooling similar to 3 degrees c stronger wind 20ms 1 and heavy rainfall 100mmday 1 were seen in the above regions the offshore bloom occurred where parma s translation speed was the slowest similar to 1ms 1 it may be caused primarily by the ekman pumping which brought nutrients upward to the euphotic zone and also by the entrainment mixing the nearshore bloom may be triggered by the heavy typhoon induced rainfall which supplied nutrients for the coast region north of luzon island the rapid increase of cdom in the nearshore region implied that terrestrial input may be the source of nutrients

global marine gravity from retracked geosat and ers 1 altimetry ridge segmentation versus spreading rate 1 three approaches are used to reduce the error in the satellite derived marine gravity anomalies first we have retracked the raw waveforms from the ers 1 and geosat gm missions resulting in improvements in range precision of 40 and 27 respectively second we have used the recently published egm2008 global gravity model as a reference field to provide a seamless gravity transition from land to ocean third we have used a biharmonic spline interpolation method to construct residual vertical deflection grids comparisons between shipboard gravity and the global gravity grid show errors ranging from 2 0 mgal in the gulf of mexico to 4 0 mgal in areas with rugged seafloor topography the largest errors of up to 20 mgal occur on the crests of narrow large seamounts the global spreading ridges are well resolved and show variations in ridge axis morphology and segmentation with spreading rate for rates less than about 60 mm a the typical ridge segment is 50 80 km long while it increases dramatically at higher rates 100 1000 km this transition spreading rate of 60 mm a also marks the transition from axial valley to axial high we speculate that a single mechanism controls both transitions candidates include both lithospheric and asthenospheric processes

the 3d oceanic mixed layer response to hurricane gilbert upper ocean heat and mass budgets are examined from three snapshots of data acquired during and after the passage of hurricane gilbert in the western gulf of mexico measurements prior to storm passage indicated a warm core eddy in the region with velocities of o 1 m s21 based upon conservation of heat and mass the threedimensional mixed layer processes are quantified from the data during and subsequent to hurricane passage horizontal advection due to geostrophic velocities is significant in the eddy regime suggesting that prestorm oceanic variability is important when background flows have the same magnitude as the mixed layer current response storm induced near inertial currents lead to large vertical advection magnitudes as they diverge from and converge toward the storm track surface fluxes estimated by reducing flight level winds to 10 m indicate a maximum wind stress of 4 2 n m22 and a heat flux of 1200 w m 22 in the directly forced region the upward heat flux after the passage of the storm has a maximum of 200 w m22 corresponding to a less than 7 m s21 wind speed entrainment mixing across the mixed layer base is estimated using three bulk entrainment closure schemes that differ in their physical basis of parameterization entrainment remains the dominant mechanism in controlling the heat and mass budgets irrespective of the scheme depending on the magnitudes of friction velocity surface fluxes and or shear across the mixed layer base the pattern and location of maximum entrainment rates differ in the directly forced region while the general area of maximum entrainment is in the right rear quadrant of the storm shear induced entrainment scheme predicts a narrow region of cooling compared to the the stressinduced mixing scheme and observed sst decreases after the storm passage the maximum contribution to the mixed layer dynamics is associated with shear induced entrainment mixing forced by near inertial motions up to the third day as indicated by bulk richardson numbers that remained below criticality thus entrainment based on a combination of surface fluxes friction velocity and shear across the entrainment zone may be more relevant for three dimensional ocean response studies

the syrian arc system an overview abstract a comparison between the ne directed negev and palmyra foreland monoclines of the syrian arc shows strong similarity in both their statigraphy and late mesozoic and cenozoic tectonic history a first phase of simple folding in the senonian was followed by a phase of reverse faulting in the miocene and ended with a phase of post miocene uplift in the style of fault bend fold this triple deformation of the north arabian subplate was contemporaneous with the thrusting of the tauros zagros zone the ne sw direction of the syrian arc as well as many other structures on the african and arabian plates are an inherited ancient feature predating any contact with the eurasian plate the continental drift proposed for turkey and arabia is reviewed and rejected for both the amounts of horizontal displacement of the dead sea rift and the east anatolian fault are estimated to be 45 and 27 km respectively it is suggested that the stress system upon the levant has been nw directed since the late cretaceous to the present time the dead sea rift n s stress direction is a local post miocene response to limited regional shift and to intense uplift

impact of upper ocean thermal structure on the intensity of korean peninsular landfall typhoons the roles of oceanic factors in the intensity of typhoons which made landfall on the korean peninsula kp are investigated using various meteorological and oceanic measurements and the best track data special attention is given an investigation of upper ocean thermal conditions necessary for becoming the most destructive typhoons on the kp based on hydrographic measurements and ocean modeling results the subsurface thermal structure sts along the track of the kp landfall typhoons reveals two distinct features the deep subsurface warm layer regions influenced by the kuroshio branch current west of kyushu kbcwk and the tsushima current tsc and the shallow subsurface warm layer regions influenced by the yellow sea bottom cold water ysbcw jeju island is a border dividing the two regions statistical analysis shows that 70 90 of the 10 strongest typhoons on the kp passed through the eastern side of jeju island where the warm ocean currents exist at the subsurface in contrast the majority of typhoons which passed over the ysbcw regions where cold water exists at the subsurface along the western side of jeju island experience a large surface temperature cooling due to the storm s self induced vertical mixing and upwelling resulting in a significant decrease in intensity these results demonstrate that the intensity of the kp landfall typhoons is very sensitive to the storm s track and how the difference in the upper ocean thermal structures in small areas can affect the typhoon intensity change

rapid weakening of tropical cyclones in monsoon gyres over the tropical western north pacific abstractas one major source of forecasting errors in tropical cyclone intensity rapid weakening of tropical cyclones an intensity reduction of 20 kt or more over a 24 h period over the tropical open ocean can result from the interaction between tropical cyclones and monsoon gyres this study aims to examine rapid weakening events occurring in monsoon gyres in the tropical western north pacific wnp basin during may october 2000 2014 although only less than one third of rapid weakening events happened in the tropical wnp basin south of 25 n more than 40 of them were associated with monsoon gyres about 85 of rapid weakening events in monsoon gyres occurred in september and october the rapid weakening events associated with monsoon gyres are usually observed near the center of monsoon gyres when tropical cyclone tracks make a sudden northward turn the gyres can enlarge the outer size of tropical cyclones and tend to induce prolonged rapid weakening events with an average duration of 33 2 h the la

late holocene environment of subalpine northeastern taiwan from pollen and diatom analysis of lake sediments abstract we used multi decadal pollen and diatom records from sediment core tfl 1 from tsuifong lake to reconstruct the vegetation dynamics and hydroclimate in northeastern taiwan during the past 3500 cal bp coarse grained sediments in association with higher percentages of wetland pollen cyperaceae and upper conifer pollen tsuga and pinus in the lower part of the core indicate low lake levels and a relatively cold dry climate between 3500 and 2030 cal bp reflecting a decline of the east asian summer monsoon easm muddy sediments coupled with reduction of wetland pollen represent the rise of lake levels implying the re strengthening of the easm during the past 2000 years paleotemperature was inferred from the variation of pollen origin from the upper and lower mountain forest indicating the global temperature anomalies of the medieval warm period mwp and the little ice age lia in comparison to the main climate forces in the north pacific we suggest that the long term climatic trend in taiwan was controlled by variations in easm intensity while increased precipitation over the past 2000 years may also be linked to warmer sea surface temperature sst of the western pacific warm pool wpwp and increased el nino southern oscillation enso events which increased typhoon intensity higher diatom inferred ph during 2930 2030 cal bp and the lia suggest strong hydrological disturbances reflecting more typhoons passing over taiwan the frequent typhoon events could be linked by an abrupt shift of typhoon track due to the reduction of the wpwp and expansion of the northwestern pacific high which move typhoons in a more westerly direction

velocity depth ambiguity of reflection traveltimes the conversion of time horizons to depth is fundamental to exploration geophysics the interval velocity used in the conversion is often estimated from the stacking velocity assuming that each layer s interval velocity is homogeneous however even for one laterally inhomogeneous layer above a flat reflector the stacking velocity can swing violently about its average and conventional methods of velocity estimation fail i show that violent swings in the stacking velocity are a symptom of a long wavelength ambiguity between the burial depth to an interface and interval velocity lateral variations in seismic velocity with a spatial wavelength of about 2 7 d where d is the depth to the reflecting horizon cannot be unambiguously resolved from traveltime measurements the spatial wavelength of this ambiguous component varies from 2 57 d for very small source receiver separations to 2 86 d for source receiver separations equal to d spectral components of the stacking velocity at wavelengths shorter than

upper ocean thermal structure and the western north pacific category 5 typhoons part i ocean features and the category 5 typhoons intensification abstract category 5 cyclones are the most intense and devastating cyclones on earth with increasing observations of category 5 cyclones such as hurricane katrina 2005 rita 2005 mitch 1998 and supertyphoon maemi 2003 found to intensify on warm ocean features i e regions of positive sea surface height anomalies detected by satellite altimeters there is great interest in investigating the role ocean features play in the intensification of category 5 cyclones based on 13 yr of satellite altimetry data in situ and climatological upper ocean thermal structure data best track typhoon data of the u s joint typhoon warning center together with an ocean mixed layer model 30 western north pacific category 5 typhoons that occurred during the typhoon season from 1993 to 2005 are systematically examined in this study two different types of situations are found the first type is the situation found in the western north pacific south eddy zone sez 21 26 n 127 170 e and the kuroshio 21 30

effects of vertical wind shear on the intensity and structure of numerically simulated hurricanes a series of numerical simulations of tropical cyclones in idealized large scale environments is performed to examine the effects of vertical wind shear on the structure and intensity of hurricanes the simulations are performed using the nonhydrostatic pennsylvania state university national center for atmospheric research fifth generation mesoscale model using a 5 km fine mesh and fully explicit representation of moist processes when large scale vertical shears are applied to mature tropical cyclones the storms quickly develop wavenumber one asymmetries with upward motion and rainfall concentrated on the left side of the shear vector looking downshear in agreement with earlier studies the asymmetries develop due to the storm s response to imbalances caused by the shear the storms in shear weaken with time and eventually reach an approximate steady state intensity that is well below their theoretical maximum potential intensity as expected the magnitude of the weakening increases with increasing shear all of the storms experience time lags between the imposition of the large scale shear and the resulting rise in the minimum central pressure while the lag is at most a few hours when the storm is placed in very strong 15 m s21 shear storms in weaker shears experience much longer lag times with th e5ms 21 shear case showing no signs of weakening until more than 36 h after the shear is applied these lags suggest that the storm intensity is to some degree predictable from observations of largescale shear changes in all cases both the development of the asymmetries in core structure and the subsequent weakening of the storm occur before any resolvable tilt of the storm s vertical axis occurs it is hypothesized that the weakening of the storm occurs via the following sequence of events first the shear causes the structure of the eyewall region to become highly asymmetric throughout the depth of the storm second the asymmetries in the upper troposphere where the storm circulation is weaker become sufficiently strong that air with high values of potential vorticity and equivalent potential temperature are mixed outward rather than into the eye this allows the shear to ventilate the eye resulting in a loss of the warm core at upper levels which causes the central pressure to rise weakening the entire storm the maximum potential vorticity becomes concentrated in saturated portions of the eyewall cloud aloft rather than in the eye third the asymmetric features at upper levels are advected by the shear causing the upper portions of the vortex to tilt approximately downshear the storm weakens from the top down reaching an approximate steady state intensity when the ventilated layer can descend no farther due to the increasing strength and stability of the vortex at lower levels

stacking velocities in the presence of overburden velocity anomalies lateral velocity changes velocity anomalies in the overburden may cause significant oscillations in normal moveout velocities explicit analytical moveout formulas are presented and provide a direct explanation of these lateral fluctuations and other phenomena for a subsurface with gentle deep structures and shallow overburden anomalies the analytical conditions for this have been derived for a depth velocity model with gentle structures with dips not exceeding 12 the influence of lateral interval velocity changes and curvilinear overburden velocity boundaries can be estimated and analysed using these formulas an analytical approach to normal moveout velocity analysis in a laterally inhomogeneous medium provides an understanding of the connection between lateral interval velocity changes and normal moveout velocities in the presence of uncorrected shallow velocity anomalies the difference between root mean square and stacking velocity can be arbitrarily large to the extent of reversing the normal moveout function around normal incidence traveltimes the main reason for anomalous stacking velocity behaviour is non linear lateral variations in the shallow overburden interval velocities or the velocity boundaries a special technique has been developed to determine and remove shallow velocity anomaly effects this technique includes automatic continuous velocity picking an inversion method for the determination of shallow velocity anomalies improving the depth velocity model by an optimization approach to traveltime inversion layered reflection tomography and shallow velocity anomaly replacement model and field data examples are used to illustrate this technique

the southernmost margin of the tethys realm during the mesozoic and cenozoic initial geometry and timing of the inversion processes 1 along the northern border of africa pangea breakup has been diachronic during the jurassic the alpine tethys propagated northeastward from the atlantic to the alps during the permian the neo tethys propagated westward from oman to northwestern arabia then a secondary and late branch of neo tethys gave birth to the east mediterranean basin finally the two oceans connected at end of jurassic times achieving the development of africa northern plate boundary by the late cretaceous convergence between africa and eurasia led to the progressive closure of the tethys realm the continental collision is not completely achieved and the different segments of the confrontation zone maghreb central and east mediterranean zagros and oman expose different stages of the process however we emphasize the existence of synchronous geodynamic events from one end of the system to the other although they do not have the same meaning two of them are particularly important the campanian santonian c s event corresponds to 1 obduction and exhumation of high pressure low temperature metamorphic rocks around the arabian promontory 2 inversion along the margins of the east mediterranean basins and 3 lithosphere buckling in the atlas system maghreb and adjacent sahara platform the middle late eocene mle event corresponds to 1 the onset of collision at the northern corner of arabia 2 the onset of slab retreat in the mediterranean and 3 inversion along the margin of the east mediterranean as well as in the atlas the c s event coincides with a change in plate kinematics resulting in an abrupt increase of convergence velocity the mle event coincides with a period of strong coupling between the africa and eurasia plates and an abrupt decrease of convergence velocity in the middle of the system the central mediterranean seems to escape to the effects of convergence and is the site of quite permanent extensional movements since the triassic

late cretaceous ca 84 ma compressive deformation of the stable platform of northeast africa egypt far field stress effects of the santonian event and origin of the syrian arc deformation belt large scale northeast trending asymmetric folds and associated contractional faults seismically induced slump structures and strike slip and extensional faults of santonian age occur within the eastern desert of egypt 150 km south of the syrian arc mobile belt the region also displays a locally developed angular unconformity at the base of the flat lying campanian limestone these features demonstrate that the deformation event responsible for the syrian arc also led to northwest southeast shortening in central egypt ca 84 ma the late santonian shortening corresponds precisely with a brief period of compression that swept across the entire african plate coeval with a significant change in the poles of opening of the north atlantic this santonian event is a prominent example of the role that far field compressional stresses can play in stable intraplate settings

tectonics and subsidence evolution of the sirt basin libya a backstripping analysis of 225 wells located within the sirt basin libya provides new constraints on the development of the sirt basin four tectonic phases are identified from late jurassic to present the presentation of contour maps of subsidence and crustal stretching allows spatial and temporal variations in stretching to be visualized a close match is observed with stretching phases documented for other african basins consistent with discrete phases in the opening of the tethys and atlantic rifting and reactivation appear to be primarily controlled by the orientation of the basin and the underlying basement structure with respect to stress directions the tectonic subsidence curves have also been forward modeled with an automated modeling technique to quantify the variation in timing and the magnitude of rifting the tectonic subsidence history of the sirt basin is characterized by periods of stretching alternating with periods of relative tectonic quiescence and thermal subsidence stretching started at the centers of the troughs and migrated toward the platform crests

upper ocean thermal structure and the western north pacific category 5 typhoons part ii dependence on translation speed abstract using new in situ ocean subsurface observations from the argo floats best track typhoon data from the u s joint typhoon warning center an ocean mixed layer model and other supporting datasets this work systematically explores the interrelationships between translation speed the ocean s subsurface condition characterized by the depth of the 26 c isotherm d26 and upper ocean heat content uohc a cyclone s self induced ocean cooling negative feedback and air sea enthalpy fluxes for the intensification of the western north pacific category 5 typhoons based on a 10 yr analysis it is found that for intensification to category 5 in addition to the warm sea surface temperature generally around 29 c the required subsurface d26 and uohc depend greatly on a cyclone s translation speed it is observed that even over a relatively shallow subsurface warm layer of d26 60 70 m and uohc 65 70 kj cm 2 it is still possible to have a sufficient enthalpy flux to intensify the storm to category 5

some aspects of hurricane inner core dynamics and energetics abstract the energy cycle of the mature hurricane resides in the secondary circulation that passes through the storm s eyewall by equating the generation of energy in this cycle to boundary layer dissipation an upper bound on wind speed is derived this bound depends on the degree of thermodynamic disequilibrium between the tropical ocean and atmosphere on the difference between sea surface and outflow absolute temperatures and also on the ratio between the enthalpy exchange and surface drag coefficients such a bound proves to be an excellent predictor of maximum wind speeds in two different axisymmetric numerical models and does not appear to depend on the existence of the hurricane eye but further consideration of the detailed dynamics of the eye and eyewall show that the intensification of hurricanes is accelerated by feedbacks associated with a component of eye subsidence forced by radial turbulent diffusion of momentum this radial momentum diffusion is an inevitable by product of the strong fr

interval anisotropic parameter estimation from walkaway vertical seismic profiling data this paper presents a new explicit method for the estimation of layered vertical transverse isotropic vti anisotropic parameters from walkaway vsp data this method is based on dix type normal moveout nmo inversion to estimate interval anisotropic parameters above a receiver array the method uses time arrivals of surface related double reflected downgoing waves a three term nmo approximation function is used to estimate nmo velocity and a non hyperbolic parameter assuming the vertical velocity is known from zero offset vsp data dix type inversion is applied to estimate the layered thomsen anisotropic parameters above the receivers array model results show reasonable accuracy for estimates through dix type inversion results also show that in many cases we can neglect the influence of the velocity gradient on anisotropy estimates first breaks are used to estimate anisotropic parameters within the walkaway receiver interval analytical uncertainty analysis is performed to nmo parameter estimates its conclusions are confirmed by modelling

evidence for late devonian vertical movements and extensional deformation in northern africa and arabia integration in the geodynamics of the devonian world 1 the upper paleozoic geodynamic evolution is discussed at the scale of a wide part of gondwana from north africa to arabia with the aim of giving an integrated tectonic scenario for the study domain we revisit six key areas namely the anti atlas belt morocco the bechar basin west algeria the hassi r mel high central algeria the talemezane arch south tunisia the western desert egypt and finally the high zagros belt iran below the so called hercynian unconformity which is in reality a highly composite discontinuity surface and subsurface data display a well known arch and basin geometry with basement highs and intervening paleozoic basins we show that this major feature results mainly from a late devonian event and can no longer be interpreted as a far effect of the variscan orogeny this event is characterized by a more or less diffuse extensional deformation and accompanied either by subsidence in the western part of the system or by an important uplift of probable thermal origin followed by erosion and peneplanation by the end of the devonian the whole region suffered a general subsidence governed by the progressive cooling of the lithosphere such a primary configuration is preserved in arabia with typical sag geometry of the carboniferous and permian deposits but strongly disturbed elsewhere by the conjugated effects of the variscan orogeny during the carboniferous and or by subsequent uplifts linked to the central atlantic and neo tethys rifting episodes in conclusion we try to integrate this new understanding in the geodynamics of the late devonian which at world scale is characterized by the onset of the variscan orogeny on the one hand and by magmatism rifting and basement uplift on the other hand

deformation of accretionary wedges in response to seamount subduction insights from sandbox experiments sandbox experiments using a two dimensional and a three dimensional approach are used to study the deformation of margins in response to seamount subduction successive mechanisms of deformation are activated during the subduction of conical seamounts first reactivation of the frontal thrusts and compaction of the accretionary wedge is observed then back thrusting and conjugate strike slip faulting develops above the leading slope of the subducted seamount the basal d6collement is deflected upward in the wake of the subducting high and a large shadow zone develops behind the seamount trailing slope consequently frontal accretion is inhibited and part of the frontal margin is dragged into the subduction zone when the main d6collement returns to its basal level in the wake of the seamount the margin records a rapid subsidence and a new accretionary wedge develops closing the margin reentrant the sediments underthrusted in the wake of the seamount into the shadow zone are underplated beneath the rear part of the accretionary wedge substantial shortening and thickening of the deformable seaward termination of the upper plate basement associated with basal erosion is observed seamount subduction induces significant material transfer within the accretionary wedge favors large tectonic erosion of the frontal margin and thickening of the rear part of the margin the subduction and underplating of relatively undeformed water ladden sediments associated with fluid expulsion along the fractures affecting the margin could modify the fluid pressure along the basal ddcollement consequently significant variations of the effective basal friction and local mechanical coupling between the two plates could be expected around the subducting seamount

correction for the influence of velocity lenses on nonhyperbolic moveout inversion for vti media nonhyperbolic moveout analysis plays an increasingly important role in velocity model building because it provides valuable information for anisotropic parameter estimation however lateral heterogeneity associated with stratigraphic lenses such as channels and reefs can significantly distort the moveout parameters even when the structure is relatively simple we analyze the influence of a low velocity isotropic lens on nonhyperbolic moveout inversion for horizontally layered vti transversely isotropic with a vertical symmetry axis models synthetic tests demonstrate that a lens can cause substantial laterally varying errors in the normal moveout velocity vnmo and the anellipticity parameter the area influenced by the lens can be identified using the residual moveout after the nonhyperbolic moveout correction as well as the dependence of errors in vnmo and on spreadlength to remove such errors in vnmo and we propose a correction algorithm designed for a lens embedded in a horizontally

lithospheric strength variations as a control on new plate boundaries examples from the northern red sea region abstract the complex plate boundary between arabia and africa at the northern end of the red sea includes the gulf of suez rift and the gulf of aqaba dead sea transform geologic evidence indicates that during the earliest phase of rifting the red sea propagated nnw towards the mediterranean sea creating the gulf of suez subsequently the majority of the relative movement between the plates shifted eastward to the dead sea transform we propose that an increase in the strength of the lithosphere across the mediterranean continental margin acted as a barrier to the propagation of the rift a new plate boundary the dead sea transform formed along a zone of minimum strength we present an analysis of lithospheric strength variations across the mediterranean continental margin the main factors controlling these variations are the geotherm crustal thickness and composition and sediment thickness the analysis predicts a characteristic strength profile at continental margins which consists of a marked increase in strength seaward of the hinge zone and a strength minimum landward of the hinge zone this strength profile also favors the creation of thin continental slivers such as the levant west of the dead sea transform and the continental promontory containing socotra island at the mouth of the gulf of aden calculations of strength variations based on changes of crustal thickness geotherm and sediment thickness can be extended to other geologic settings as well they can explain the location of rerifting events at intracratonic basins of backarc basins and of major continental strike slip zones

characteristics of the upper tropospheric environmental flow around hurricanes abstract the upper tropospheric flow out to a radius of 2000 km around atlantic hurricanes is described using rotated coordinate composite analysis of the noaa national hurricane center operational wind set the rotated coordinate methodology designed to preserve some of the asymmetry of hurricane outflow during compositing is described in detail a rotated coordinate composite of all hurricanes from a five year period is used to study the general properties of the hurricane outflow layer coordinate rotation improves the representation of the outflow jet and the associated extrema of radial and tangential wind but tends to obscure the geographically persistent features of the upper tropospheric environment such as the midlatitude westerlies the amplitude of the asymmetric radial wind is twice that of the symmetric while the amplitudes of tangential winds are equivalent a comparison of geographic and rotated coordinate composites indicates that both the outflow jet and the midlatitude westerlies are

satellite derived ocean thermal structure for the north atlantic hurricane season abstractthis paper describes a new model method called satellite derived north atlantic profiles snap that seeks to provide a high resolution near real time ocean thermal field to aid tropical cyclone tc forecasting using about 139 000 observed temperature profiles a spatially dependent regression model is developed for the north atlantic ocean during hurricane season a new step introduced in this work is that the daily mixed layer depth is derived from the output of a one dimensional price weller pinkel ocean mixed layer model with time dependent surface forcing the accuracy of snap is assessed by comparison to 19 076 independent argo profiles from the hurricane seasons of 2011 and 2013 the rms differences of the snap estimated isotherm depths are found to be 10 25 m for upper thermocline isotherms 29 19 c 35 55 m for middle isotherms 18 7 c and 60 100 m for lower isotherms 6 4 c the primary error sources include uncertainty of sea surface height anomaly ssha high frequency fluc

a statistical analysis of the effects of vertical wind shear on tropical cyclone intensity change over the western north pacific abstractthe effect of vertical wind shear vws between different pressure levels on tc intensity change is statistically analyzed based on the best track data of tropical cyclones tcs in the western north pacific wnp from the joint typhoon warning center jtwc and the ecmwf interim reanalysis era interim data during 1981 2013 results show that the commonly used vws measure between 200 and 850 hpa is less representative of the attenuating deep layer shear effect than that between 300 and 1000 hpa moreover the authors find that the low level shear between 850 or 700 and 1000 hpa is more negatively correlated with tc intensity change than any deep layer shear during the active typhoon season whereas deep layer shear turns out to be more influential than low level shear during the remaining less active seasons further analysis covering all seasons exhibits that a tc has a better chance to intensify than to decay when the deep layer shear is lower than 7 9 m s 1 and the low level shear is below

mechanism and timing of tectonic inversion in cyrenaica libya integration in the geodynamics of the east mediterranean abstract in the eastern mediterranean the south tethys paleo margin experienced poly phased rifting episodes during paleozoic and mesozoic times this domain has been subsequently inverted by discontinuous events occurring since the late cretaceous as a consequence of the africa eurasia convergence the cyrenaica promontory northeast libya including the jabal al akhdar antiformal ridge is not yet involved in the africa eurasia collision zone it thus gives an opportunity to analyze tectonic inversions occurring early in the development of the system and their possible causal links with events occurring along the plate boundary i e within the hellenic subduction for this purpose we present new geological cross sections supported by offshore industrial 2d seismic profiles imaging the northeast prolongation of the antiformal ridge indenting the mediterranean ridge accretionary prism the onshore part of this ene wsw trending structure exposes upper cretaceous to recent sedimentary rocks well calibrations allow us to be precise about the geometry of the structure inherited from a lower cretaceous rift basin and the timing of the main tectonic events oligocene sediments seal unconformably the main episodes of contractional deformation just below growth strata of late ypresian to priabonian age indicate a protracted folding episode during the middle late eocene post dating an older late cretaceous inversion this evolution contrasts with what is observed in the adjacent sirt basin characterized at the same time by extensional deformation and subsidence finally we appraise how far these tectonic scenarios match the geodynamic evolution of the hellenic domain

structure paleogeographic inheritance and deformation history of the southern atlas foreland fold and thrust belt of tunisia 1 structural analysis of the southern tunisian atlas was carried out using field observation seismic interpretation and cross section balancing it shows a mix of thick skinned and thin skinned tectonics with lateral variations in regional structural geometry and amounts of shortening controlled by nw se oblique ramps and tear faults it confirms the role of the late triassic early jurassic rifting inheritance in the structuring of the active foreland fold and thrust belt of the southern tunisian atlas in particular in the development of nw se oblique structures such as the gafsa fault the late triassic early jurassic structural pattern is characterized by a family of first order nw se trending normal faults dipping to the east and by second order e w trending normal faults limiting a complex system of grabens and horsts these faults have been inverted during two contractional tectonic events the first event occurred between the middle turonian and the late maastrichtian and can be correlated with the onset of the convergence between africa and eurasia the second event corresponding to the principal shortening tectonic event in the southern atlas started in the serravalian tortonian and is still active during the neogene the southern atlas foreland fold and thrust belt propagated on the evaporitic decollement level infilling the late triassic early jurassic rift the major eocene atlas event described in hinterland domains and in eastern tunisia did not deform significantly the southern tunisian atlas which corresponded in this period to a backbulge broad depozone

correction to recent cooling of the upper ocean the recent cooling signal in the upper ocean reported by lyman et al 2006 is shown to be an artifact that was caused by a large cold bias discovered in a small fraction of argo floats as well as a smaller but more prevalent warm bias in expendable bathythermograph xbt data these biases are both substantially larger than sampling errors estimated in lyman et al 2006

estimate of ocean mixed layer deepening after a typhoon passage over the south china sea by using satellite data abstractthe ocean responses to typhoon cimaron which influenced the south china sea scs from 1 to 8 november 2006 are analyzed based on satellite observed sea surface temperature sst and climatological temperature profiles in the scs mixed layer deepening an important parameter characterizing turbulent mixing and upwelling driven by strong typhoon winds is derived corresponding to the sst drop of 4 4 c on 3 november 2006 the mixed layer deepened by 104 5 m relative to the undisturbed depth of 43 2 m which is consistent with a simulation result from a mixed layer model furthermore baroclinic geostrophic velocity and vorticity are calculated from the surface temperature gradient caused by the typhoon the negative vorticity associated with the typhoon cooling indicated an anticyclonic baroclinic circulation strongest at the base of the mixed layer and at the depth of 50 m the geostrophic speed reached as high as 0 2 m s 1 typhoon cimaron proceeded slowly 1 7 m s 1 when it was making a s

velocity modeling of a long period static anomaly west cameron block 225 a gulf of mexico case history the local structure at west cameron block 225 offshore louisiana was originally interpreted as a double crested anticlinal feature production was established on both crests a deviated well was later drilled toward the intervening saddle the well was structurally higher than the supposed crestal wells and found three additional pay sands the revised interpretation assumed that the structural saddle was a long period static anomaly this interpretation produced a single anticlinal feature with substantial attic reserves in drilling the well to tap these attic reserves many of the expected pay sands were found to be wet or missing the well was structurally lower relative to the previous wells at nearly all the marker beds velocity sag was indeed present however only 60 percent of the correction applied to the seismic data could be accounted for in this manner the stacking velocity profile was modeled for the maximum velocity sag interpretation using two horizons the modeled profiles exhibit the

variability of upper ocean characteristics and tropical cyclones in the south west indian ocean track and intensity are key aspects of tropical cyclone behavior intensity may be impacted by the upper ocean heat content relevant for tc intensification known as tdy and barrier layer thickness blt here the variability of tdy and blt in the south west indian ocean and their relationships with tropical cyclones are investigated it is shown that rapid cyclone intensification is influenced by large tdy values thick barrier layers and the presence of anticyclonic eddies for tc generation in the south west indian ocean the parameter tdy was found to be important large blt values overlay with large tdy values during summer both fields are modulated by the westward propagation of rossby waves which are often associated with enso for example the 1997 1998 el nino shows a strong signal in tdy sst and blt over the south west indian ocean after this event an increasing trend in tdy occurred over most of the basin which may be associated with changes in atmospheric circulation increasing sst power dissipation index and frequency of category 5 tropical cyclones also occurred from 1980 to 2010 to further examine the links between tropical cyclones tdy and blt the ocean response to category 5 tropical cyclone bansi that developed near madagascar during january 2015 was analyzed its unusual track was found to be linked with the strengthening of the monsoonal north westerlies while its rapid intensification from category 2 to category 4 was linked to a high tdy region associated with a warm core eddy and large blt

influence of the size of supertyphoon megi 2010 on sst cooling abstractsupertyphoon megi 2010 left behind two very contrasting sst cold wake cooling patterns between the philippine sea 1 5 c and the south china sea 7 c based on various radii of radial winds we found that the size of megi doubles over the south china sea when it curving northwards on average the radius of maximum wind rmw increased from 18 8 km over the philippine sea to 43 1 km over the south china sea the radius of 64 kt typhoon force wind r64 increased from 52 6 km to 119 7 km the radius of 50 kt damaging force wind r50 increased from 91 8 km to 210 km and the radius of 34 kt gale force wind r34 increased from 162 3 km to 358 5 km to investigate the typhoon size effect we conduct a series of numerical experiments on megi induced sst cooling by keeping other factors unchanged i e typhoon translation speed and ocean subsurface thermal structure the results show that if it were not for megi s size increase over the south china sea the during megi sst cooling magnitude woul

the interaction of supertyphoon maemi 2003 with a warm ocean eddy understanding the interaction of ocean eddies with tropical cyclones is critical for improving the understanding and prediction of the tropical cyclone intensity change here an investigation is presented of the interaction between supertyphoon maemi the most intense tropical cyclone in 2003 and a warm ocean eddy in the western north pacific in september 2003 maemi passed directly over a prominent 700 km 500 km warm ocean eddy when passing over the 22 n eddy rich zone in the northwest pacific ocean analyses of satellite altimetry and the best track data from the joint typhoon warning center show that during the 36 h of the maemi eddy encounter maemi s intensity in 1 min sustained wind shot up from 41 ms 1 to its peak of 77 m s 1 maemi subsequently devastated the southern korean peninsula based on results from the coupled hurricane intensity prediction system and satellite microwave sea surface temperature observations it is suggested that the warm eddies act as an effective insulator between typhoons and the deeper ocean cold water the typhoon s self induced sea surface temperature cooling is suppressed owing to the presence of the thicker upper ocean mixed layer in the warm eddy which prevents the deeper cold water from being entrained into the upper ocean mixed layer as simulated using the coupled hurricane intensity prediction system the incorporation of the eddy information yields an evident improvement on maemi s intensity evolution with its peak intensity increased by one category and maintained at category 5 strength for a longer period 36 h of time without the presence of the warm ocean eddy the intensification is less rapid this study can serve as a starting point in the largely speculative and unexplored field of typhoon warm ocean eddy interaction in the western north pacific given the abundance of ocean eddies and intense typhoons in the western north pacific these results highlight the importance of a systematic and in depth investigation of the interaction between typhoons and western north pacific eddies

an overview of the late cretaceous eocene positive inversions and oligo miocene subsidence events in the foreland of the tunisian atlas structural style and implications for the tectonic agenda of the maghrebian atlas system abstract structural interpretation of surface and subsurface data in the eastern foreland basins of tunisia allows us to recognize positive inversion structures i e related to compressional events expressed and recorded in the paleogene sedimentary pile of the atlas domain these episodes are followed by a period of relative tectonic quiescence during oligocene early miocene with development of extensional structures with slightly tilted panels grabens and locally the development of listric normal faults branched at depth on decollement levels comparison of the seismic interpretations and field data collected along the south atlas front as well as in the atlas belt allows us to propose a tectonic scenario at the scale of eastern tunisia atlas in particular we emphasise the role of the so called atlas event middle late eocene which was initially defined in algeria but poorly outlined in tunisia we will show that the tectonic agenda defined in eastern tunisia is consistent with the one proposed elsewhere in the maghreb allowing us to propose a unified view of the geodynamic evolution of the whole atlas system during this period the negative inversion recorded during oligocene early miocene along with the occurrence of synsedimentary normal faults are related to an increase of the subsidence rate in the frame of continuous shortening coeval to basin formation in the front of the atlas the whole oligo miocene evolution results from two different mechanisms flexuration in the front of the atlas and the onset of the extension of the pantelleria linosa malta rift system of central mediterranean which attained a climax stage later during pliocene quaternary

an ocean coupling potential intensity index for tropical cyclones american geophysical union 2013 this article is posted here by permission of american geophysical union for personal use not for redistribution the definitive version was published in geophysical research letters 40 2013 1878 1882 doi 10 1002 grl 50091

examples of deep water play types in the matruh and herodotus basins of nw egypt numerous deep water play types have been identified along the transform margin of nw egypt a large segment of the offshore matruh basin has play types related to a prominent shale decollement within the matruh canyon the footwalls of the growth faults associated with the shale detachment provide fault controlled three way closures very similar to the well known rafts in the lower congo basin in west africa as updip extension transitions to downdip contraction some thin skinned toe thrust imbrications can be found in the ultradeep water part of matruh basin another important play type in the deep water offshore matruh basin is related to the prominent syn rift hinge zone of an interpreted transform margin of the eastern mediterranean this play type could serve as a play opener along the transform margin of nw egypt and ne libya the offshore matruh and herodotus basins of nw egypt represent an underexplored region of the mediterranean with only one deep water well drilled along the margin to date

the opening of sirte basin result of slab avalanching abstract north africa s sirte basin opening is an enigmatic feature in the complex meso cenozoic rearrangement of mediterranean tectonics new borehole data inversion constrains its deformation history showing a stretching event starting 70 ma and terminating in a further abrupt increase at 50 ma rapidly fading afterwards the timing of this event hardly reconciles with the mesozoic major plates reorganization following the spreading of the atlantic and the neogene central mediterranean tectonics active at different times here we propose that sirte rifting could have been driven by the pull exerted by the hellenic subduction reconstructions of hellenic convergence and slab deep subduction as constrained by plate kinematics and tomography show that large slab mass accumulates in the upper mantle by late cretaceous paleogene eventually forcing further sinking in the lower mantle coeval to the growing strain evolution recorded in sirte furthermore the 20 m y phase of large pull here recorded the consequent rapid growth over 10 m y and following decay are compatible with the dynamics of slab avalanche as revealed by numerical models showing that the sirte basin opened in response to the large pull force developed during the mass flush and transferred from deep slab to surface

spatial and temporal characterization of sea surface temperature response to tropical cyclones abstractthe spatial structure and temporal evolution of the sea surface temperature sst anomaly ssta associated with the passage of tropical cyclones tcs as well as their sensitivity to tc characteristics including tc intensity and translation speed and oceanic climatological conditions represented here by latitude are thoroughly examined by means of composite analysis using satellite derived sst data the magnitude of the tc generated ssta is larger for more intense slower moving and higher latitude tcs and it occurs earlier in time for faster moving and higher latitude storms the location of maximum ssta is farther off the tc track for faster moving storms and it moves toward the track with time after the tc passage the spatial extension of the cold wake is greater for more intense and for slower moving storms but its shape is quite independent of tc characteristics consistent with previous studies the calculations show that the mean ssta over a tc centered box nearly linearly corre

migration velocity analysis for ti media in the presence of quadratic lateral velocity variation abstractone of the most serious problems in anisotropic velocity analysis is the trade off between anisotropy and lateral heterogeneity especially if velocity varies on a scale smaller than the maximum offset we have developed a p wave mva migration velocity analysis algorithm for transversely isotropic ti models that include layers with small scale lateral heterogeneity each layer is described by constant thomsen parameters e and and the symmetry direction velocity v0 that varies as a quadratic function of the distance along the layer boundaries for tilted ti media tti the symmetry axis is taken orthogonal to the reflectors we analyzed the influence of lateral heterogeneity on image gathers obtained after prestack depth migration and found that quadratic lateral velocity variation in the overburden can significantly distort the moveout of the target reflection consequently medium parameters beneath the heterogeneous layer s are estimated with substantial error even when borehole informa

hurricane intensity and eyewall replacement observations made during the historic 2005 hurricane season document a case of eyewall replacement clouds outside the hurricane eyewall coalesce to form a new eyewall at a greater radius from the storm center and the old eyewall dies the winds in the new eyewall are initially weaker than those in the original eyewall but as the new eyewall contracts the storm reintensifies understanding this replacement mechanism is vital to forecasting variations in hurricane intensity processes in the moat region between the new and old eyewall have been particularly unclear aircraft data now show that the moat becomes dynamically similar to the eye and thus is converted into a region inimical to survival of the inner eyewall we suggest that targeting aircraft to key parts of the storm to gain crucial input to high resolution numerical models can lead to improvements in forecasting hurricane intensity

satellite observations of modulation of surface winds by typhoon induced upper ocean cooling 1 two remote sensing data sets the tropical rainfall measurement mission sea surface temperature sst and the nasa quikscat ocean surface wind vectors are analysed to study ocean atmosphere interactions in cold sst regions formed in the trail of two typhoon events anomalously cold sst patches up to 6 c below the surrounding warm tropical ocean sst are found along the trail of typhoon tracks as cold deep waters are entrained up to the mixed layer due to typhoon forcing in both typhoon events significant and systematic weakening of surface wind speed is found over cold sst patches relative to surface wind speed in surrounding regions the wind speed anomalies disappear as the patches recover to the level of the surrounding sst the results are consistent with the mechanism proposed by wallace et al that surface winds are modulated by sst via stability as wind within the well mixed boundary layer moves over the cold patch boundary layer stability increases vertical mixing is suppressed and the vertical wind shear increases reduction in surface wind speed is caused in particular our result shows that this mechanism can act on relatively small spatial 100 km and short 1 day time scales

time variant statics corrections during interpretation even though statics processing is well advanced and is routinely applied interpreters are still required to evaluate seismic data that has either no statics corrections or poor statics corrections it is a critical interpretation skill to recognize uncorrected statics and to correct for their effects poor decisions and dry holes are often the result of failure to do this since multifold seismic data has become the norm statics are no longer time invariant the method of flattening stacked data on a shallow reflector that worked so well for single fold data will show anomalous structure and isochron variation caused by the time variant effects of uncorrected statics uncorrected statics can be identified by anomalous undulations in a shallow reflector by the time variant effects with increasing reflection time and by the variations in optimal stacking velocities all of which have been documented in the literature knowledge of these properties from stacked data observations can lead to robust estima

cyrenaican shock absorber and associated inversion strain shadow in the collision zone of northeast africa far field compressional stresses resulting from arc collisions with the northeast coast of africa arabia propagated across the african plate in the santonian ca 84 ma and later similar pulses occurred through much of the cenozoic waves of inversion related features including folds thrusts and igneous activity developed during the compressional events structures generated were uneven in intensity and distribution and were commonly concentrated in existing rifts because of the irregular shapes of the north african continental margin and associated inboard basins cyrenaica underwent the most severe shortening although deformation extended eastward from libya to the levant areas south and southeast of cyrenaica the sirt basin and the far western desert of egypt underwent very little shortening because they occupied a regional strain shadow the eastern region of the western desert and sinai which were not sheltered by the stress absorbing cyrenaica inversion recorded strong compressional deformation synchronous with that in cyrenaica as closure of the mediterranean continues cyrenaica will become an indenter comparable to those of other orogenic belts the detailed tectonic evolution of individual northeast african basins has depended on their positions in relation to the cyrenaican strain shadow no single subsidence and paleostress history reflects the complete regional development of the converging mediterranean north african margin

removal of overburden velocity anomaly effects for depth conversion a method of compensating for the presence of discrete overburden velocity anomalies during depth conversion of time horizons interpreted on conventional post stack time migrated seismic data is presented positive and negative time delays are estimated either from the push down or pull up of reflectors directly beneath the anomalies or from interpreted time thickness of the anomalous body and interval velocities estimated from well data the critical steps are pre stack simulation of seismic acquisition across the velocity anomalies incorporating the effects of a fresnel volume which changes its width as a function of depth and simulation of commonmidpoint cmp stacking using a linear regression of time delay at versus offset squared x 2 the time correction method predicts the time distortion for any target horizon and the distortion is removed as a correction in time depth conversion is then performed using a background velocity function the final average velocity map is calculated from the resulting depth structure and the raw times at the target horizon the method is implemented by manipulating time grids within an industry standard mapping package the final average velocity map shows steep lateral velocity gradients which are constrained by the interpreted boundaries of the velocity anomalies

two ship deep seismic soundings in the basins of the eastern mediterranean sea pasiphae cruise summary new results from a two ship refraction and oblique reflection deep seismic cruise are presented to discuss the nature of the crust in the ionian sirte and herodotus abyssal plains these expanding spread profiles were processed and analysed in both the x t and p domains arrival times of reflected and refracted branches are matched by ray tracing in both domains in spite of a shallow evaporitic sequence messinian evaporites deposited on top of a thick sedimentary pile responsible for velocity inversions on many profiles we obtain excellent velocity control down to moho depth pmp and pn 8 4 8 6 km s 1 arrivals are observed the three basins have a relatively thin crust 8 to 11 km overlain by a thick sedimentary cover up to 10km in the herodotus abyssal plain the moho boundary and main crustal units identified in the basins can be followed beneath the calabrian prism to the west and beneath the mediterranean ridge to the east the crustal structure is of oceanic type for both the ionian and sirte basins where typical oceanic layer 2 and 3 are recognized the thin crust of the herodotus basin may be interpreted either as oceanic or thinned continental crust about 10 km thick the top of the crust of the herodotus basin is much deeper therefore the herodotus basin is probably significantly older than the ionian basin triassic versus early cretaceous in age

kinematic evolution of the tethys belt from the atlantic ocean to the pamirs since the triassic abstract we present an updated series of kinematic reconstructions of the major plates around the tethys from the atlantic ocean to the pamirs between the early jurassic and the present this set is used elsewhere as a basis for paleogeographic maps of the entire region the problems related to the positions of the continents in the lower triassic are also discussed no direct analyses of magnetic anomalies and fracture zones in the atlantic have been made rather all available poles and rotations have been tested in order to eliminate or minimize possible kinematic errors the reconstructions are shown for nine key geological periods which correspond to well recognized magnetic anomalies except for the jurassic cretaceous boundary and the cretaceous tertiary boundary which correspond to interpolated positions paleolatitudes have been drawn using the study of westphal et al 1986 an attempt has been made to take into account the displacements caused by formation of the continental margins and basins by stretching the resulting relative vector of motions along the northern boundary of the tethys shows a significant change 80 m y ago left lateral motion with compression dominates before whereas right lateral motion with compression dominates after to the east rates of motion vary by a factor of three with time and four maxima can be clearly related to tectonic events in the late jurassic late cretaceous eocene and post middle miocene to the west north of apulia on the contrary the motion rate has not changed significantly since the early cretaceous and is close to 1 cm yr as an average these rather complex adjustments in rates and directions of relative motion are produced in great part through a complex migration of the africa eurasia pole of rotation and seem to be mostly governed by the tectonics of the tethys plate boundary

arabia eurasia collision and the forcing of mid cenozoic global cooling the end of the eocene greenhouse world was the most dramatic phase in the long term cooling trend of the cenozoic era here we show that the arabia eurasia collision and the closure of the tethys ocean gateway began in the late eocene at 35 ma up to 25 million years earlier than in many reconstructions we suggest that global cooling was forced by processes associated with the initial collision that reduced atmospheric co2 these are 1 waning volcanism across southwest asia 2 increased organic carbon storage in paratethyan basins e g black sea and south caspian 3 increased silicate weathering in the collision zone and 4 a shift towards modern patterns of ocean currents associated with increased vigour in circulation and organic productivity

moveout analysis of wide azimuth data in the presence of lateral velocity variation moveout analysis of wide azimuth reflection data seldom takes into account lateral velocity variations on the scale of spreadlength however velocity lenses such as channels and reefs in the overburden can cause significant laterally varying errors in the moveout parameters and distortions in data interpretation here we present an analytic expression for the normal moveout nmo ellipse in stratified media with lateral velocity variation the contribution of lateral heterogeneity lh is controlled by the second derivatives of the interval vertical traveltime with respect to the horizontal coordinates along with the depth and thickness of the lh layer this equation provides a quick estimate of the influence of velocity lenses and can be used to substantially mitigate the lens induced distortions in the effective and interval nmo ellipses to account for velocity lenses in nonhyperbolic moveout inversion of wide azimuth data we propose a prestack correction algorithm that involves computation of the lens induced traveltime distortion for each recorded trace the overburden is assumed to be composed of horizontal layers one of which contains the lens but the target interval can be laterally heterogeneous with dipping or curved interfaces synthetic tests for horizontally layered models confirm that our algorithm accurately removes lens related azimuthally varying traveltime shifts and errors in the moveout parameters the developed methods should increase the robustness of seismic processing of wide azimuth surveys especially those acquired for fracture characterization purposes

tropical cyclone induced ocean response a comparative study of the south china sea and tropical northwest pacific abstractthe thermocline shoals in the south china sea scs relative to the tropical northwest pacific ocean nwp as required by geostrophic balance with the kuroshio the present study examines the effect of this difference in ocean state on the response of sea surface temperature sst and chlorophyll concentration to tropical cyclones tcs using both satellite derived measurements and three dimensional numerical simulations in both regions tc produced sst cooling strongly depends on tc characteristics including intensity as measured by the maximum surface wind speed translation speed and size when subject to identical tc forcing the sst cooling in the scs is more than 1 5 times that in the nwp which may partially explain weaker tc intensity on average observed in the scs both a shallower mixed layer and stronger subsurface thermal stratification in the scs contribute to this regional difference in sst cooling the mixed layer effect dominates when tcs are weak fast moving and or small

transient modulation of kuroshio upper layer flow by directly impinging typhoon morakot in east of taiwan in 2009 this study deals with the modulation of the kuroshio upper layer flow kulf in response to the passage of typhoon morakot in 2009 using regional oceanic modeling system roms and in situ measurements from argos drifters and argo floats the analysis of the simulated current fields near the typhoon track revealed an intermittency phenomenon of the kulf which was almost shut down for at least 6 hours the process begun 2 days prior to the approach of typhoon center due to blockage of the kulf by the steadily northerly winds and lasted for more than 2 days simultaneously shifting the kuroshio main stream kms path when the morakot gradually moved closely to the kuroshio the kms shifted vertically from the surface layer to deeper layer of 50 100 m depth and the maximum current speed in the kms decreased from more than 1 3 m s 1 to less than 1 1 m s 1 when the morakot center approached about 100 km to the original position of the kuroshio the kulf spread eastward for 1 5 degrees at 24 n when the morakot center moved to the original position of the kms the kuroshio abruptly rushed with a maximum speed near 1 4 m s 1 meanwhile an offshore cool jet originating from southeastern tip of taiwan was generated and extended northward along the kuroshio in the cool jet the lowest temperature reached about 5 c lower than the ambient waters modeled current variations and the cool jet during the morakot passage were validated by in situ measurements

near surface faulting effects on seismic reflection times the depth conversion of seismic reflection records has been the subject of many papers particularly where faults or other geologic features are present the common depth point cdp stacked seismic sections with large spread lengths of the order of 2 km have resulted in different interpretation problems al chalabi 1979 considered the effect on stacking velocities of subsurface inhomogeneities where different rays in the cdp gather do not penetrate the same type of earth column he showed that small time delays of 10 msec produce steps in the hyperbolic offset distance time curve of the cdp gather and produce stacking velocity variations of the order of ten percent levin 1973 considered a time delay in only one ray of the cdp gather and its effect on both stacking velocity and the zero offset time t0 this paper models the effect of near surface faults on the zero offset time t0 of deeper layers as determined by the cdp method this is particularly important since the zero offset time is plotted on

constrains on the origin and history of the eastern mediterranean basin abstract the basin formed along the northern passive margin of gondwanaland as a relict of the mesozoic neotethys in early mesozoic time though direct information from the basin itself is meagre the geology of its passive margins and the regional framework of the tethys evolution constrain the formation and history of the basin the eastern mediterranean and its passive margins are interpreted to have formed as a result of several faulting and continental breakup phases from early permian to middle jurassic times before pangaea s complete disintegration this led to the detachment of the eratosthenes and tauride blocks from the margins of the levant and herodotus basins respectively the latter merged in the northeast with the cyprus basin that extended along arabia s northern margin the main rifting probably occurred in the triassic leading to seafloor spreading in the herodotus and cyprus basins while along the levant margin important rifting also occurred in the jurassic during the initial rifting stages extension perpendicular to the levant margin was important but subsequently the tauride block drifted mainly northward the existence of the passive margins and slopes of the eastern mediterranean is documented at least from the end of the middle jurassic until then the basin was probably narrow 200 300 km but during the main phase of the africa laurasia separation it grew to twice its present width or more this scenario depends critically on the interpretation that the tauride block was originally located next to northeastern africa on the western side of the eratosthenes block plate convergence and consumption of the northern portion of the basin have taken place since mid cretaceous times but the active convergent boundary on its northern side formed only in the neogene by modification of earlier structures some intra plate deformation also took place especially in the neogene but it hardly changed the original configuration of the remaining portion of the basin

a miocene tectonic inversion in the ionian sea central mediterranean evidence from multichannel seismic data it is widely accepted that the central and eastern mediterranean are remnants of the neo tethys however the orientation and timing of spreading of this domain remain controversial here we present time migrated and pre stack depth migrated nw se oriented archimede 1997 lines together with the prismed01 1993 profile to constrain the evolution of the ionian basin our interpretation allows us to identify a large scale set of sw ne striking reverse faults beneath the ionian abyssal plain these primarily nw vergent faults are characterized by a spacing comprised between 10 to 20 km and a dip ranging from 60 to 65 degree sign following very recent paleogeographic reconstructions we propose that the set of n degree sign 55 features initially formed as normal faults during the nw se trending seafloor spreading of the ionian basin after its late triassic early jurassic rifting based on geometric comparisons with the intraplate deformation observed beneath the central indian ocean we show that the inherited oceanic normal faults were reactivated under compression as reverse faults well developed tortonian syntectonic basins developed nw of the major faults and the base of the messinian evaporites mobile unit is slightly folded by the activity of the faults we show that 3 4 km of total shortening occurs over a 80 km wide area beneath the ionian abyssal plain resulting in a bulk shortening of 3 5 5 we propose a link between the tortonian early messinian inversion of the fault pattern and a plate tectonic reorganization prior to the main phase of back arc opening of the tyrrhenian domain