episodic fluid migration in the fennoscandian shield recorded by stable isotopes rare earth elements and fluid inclusions in fracture minerals at forsmark sweden abstract drilling through the palaeoproterozoic bedrock at forsmark central sweden during the site investigation for a potential geological repository of highly radioactive nuclear waste has provided high quality drill core material from the upper 1 km of the fennoscandian shield analyses of stable isotopes 13c 18o 34s 87sr 86sr rare earth elements and fluid inclusions in fracture filling calcite and pyrite from these drill cores have resulted in the discrimination of several episodes of fracture mineralisations these events represent migration of fluids during a wide range of conditions ranging from high temperature hydrothermal to present day groundwater circulation four major events have been distinguished 1 precipitation of epidote chlorite and quartz under hydrothermal conditions t 150 200 c during the proterozoic sometime between 1 8 and 1 1 ga 2 hydrothermal circulation at temperatures close to 200 c with precipitation of adularia albite prehnite laumontite calcite and chlorite most of these minerals precipitated during a tectonothermal event between 1 1 and 1 0 ga possibly in response to far field effects of the sveconorwegian orogeny 3 precipitation of mainly quartz calcite pyrite and asphaltite occurred during the palaeozoic at temperatures between 60 and 190 c mainly at

global teleconnections in response to a shutdown of the atlantic meridional overturning circulation abstract the global response to a shutdown of the atlantic meridional overturning circulation amoc is investigated by conducting a water hosing experiment with a coupled ocean atmosphere general circulation model in the model the addition of freshwater in the subpolar north atlantic shuts off the amoc the intense cooling in the extratropical north atlantic induces a widespread response over the global ocean in the tropical atlantic a sea surface temperature sst dipole forms with cooling north and warming on and south of the equator this tropical dipole is most pronounced in june december displacing the atlantic intertropical convergence zone southward in the tropical pacific a sst dipole forms in boreal spring in response to the intensified northeast trades across central america and triggering the development of an el nino like warming that peaks on the equator in boreal fall in the extratropical north pacific a basinwide cooling of 1 c takes place with a general westward increase in in

coupled ocean atmosphere response to north tropical atlantic sst tropical atlantic dipole and enso 1 the coupled ocean atmosphere response to changes of the north tropical atlantic nta sst is investigated using a coupled ocean atmosphere general circulation model the model explicitly demonstrates that a nta sst anomaly can organize an inter hemispheric sst dipole in boreal spring over both the tropical atlantic and eastern tropical pacific primarily through a coupled wind evaporative sst wes feedback while the tropical atlantic dipole eventually decays in summer and fall the eastern tropical pacific dipole subsequently evolves into an enso like pattern through the seasonal migration of the itcz and coupled ocean atmosphere feedbacks

nao implicated as a predictor of northern hemisphere mean temperature multidecadal variability 1 the twentieth century northern hemisphere mean surface temperature nht is characterized by a multidecadal warming cooling warming pattern followed by a flat trend since about 2000 recent warming hiatus here we demonstrate that the north atlantic oscillation nao is implicated as a useful predictor of nht multidecadal variability observational analysis shows that the nao leads both the detrended nht and oceanic atlantic multidecadal oscillation amo by 15 20 years theoretical analysis illuminates that the nao precedes nht multidecadal variability through its delayed effect on the amo due to the large thermal inertia associated with slow oceanic processes an nao based linear model is therefore established to predict the nht which gives an excellent hindcast for nht in 1971 2011 with the recent flat trend well predicted nht in 2012 2027 is predicted to fall slightly over the next decades due to the recent nao decadal weakening that temporarily offsets the anthropogenically induced warming

quasi stationary jets transporting surface warm waters across the transition zone between the subtropical and the subarctic gyres in the north pacific 1 surface flow jets and associated sea surface temperature sst distribution are investigated in the northwestern north pacific using satellite derived surface currents and sst data that can resolve fine spatial scale structure the combined use of these data reveals warm tongue phenomena driven by surface geostrophic jets which extend northeastward in the kuroshio oyashio transition area they roughly coincide with the subarctic front saf defined as the 4 c isotherm at 100 m depth the phenomena appear throughout the year with seasonal cycles which do not correspond with that of the subarctic north pacific their positions are affected by bottom topography so that their quasi stationary and consistent features are suggested thus it is implied that these jets play an important role in transporting warm waters toward the subarctic region the time series of sst and current fields describe the jets year to year variability involving some changes in strength and connections with the kuroshio extension ke and demonstrate the effects of advection by the jets on sst fields when ke extends northward at its crests for 1999 2002 one of the jets along saf simultaneously strengthens resulting in high sst region directly over and along the south side of the jet hydrographic data show warm saline water intrusions along the jets their mean fields also reveal that these jets are vertically well developed forming a boundary between the subtropical and subarctic gyres in the north pacific

kuroshio extension variability and forcing of the pacific decadal oscillations responses and potential feedback abstract a forcing mechanism is sought for the large scale circulation changes in the kuroshio extension region of the western north pacific ocean as inferred by topex poseidon sea surface height ssh data the low frequency signal of the kuroshio extension over the last decade was characterized by a modulation in its zonal mean flow intensity the mean kuroshio extension jet weakened progressively from 1993 to 1996 and this trend reversed after 1997 the ability to simulate the major trends in the observed ssh signals with linear vorticity dynamics leads the authors to conclude that the modulation in the zonal mean jet was remotely forced by wind stress curl anomalies in the eastern north pacific ocean related to the pacific decadal oscillations pdos to be specific the weakening strengthening trend in 1993 96 1997 2001 was caused by westward expansions of negative positive ssh anomalies south of the kuroshio extension and positive negative ssh anomalies north of the kuroshio extension emerg

mesoscale sst dynamics in the kuroshio oyashio extension region abstractmesoscale eddies have been extensively studied based on the sea surface height anomaly ssha however it is the sea surface temperature anomaly ssta that is vital to the mesoscale eddy

stable isotopes of fissure filling calcite from finnsjon uppland sweden 18o and 13c was analysed for calcite fissure fillings from different depths down to 533 m in svecokarelian rocks of east sweden a significant correlation with depth is noticed for 18o there also are differences between sealed and open fissure fillings in both 18o and 13c calcite fillings which originated in high and low temperature fluids have been found within single fissures these calcites have different textures one population of calcite has 18o values of 5 7 to 9 0 and has been precipitated by water enriched in 18o relative to that now present in the bedrock another population of calcite generally has 18o values of 17 0 to 19 5 and 13c values of 2 5 to 5 5 these calcites have been precipitated under hydrothermal conditions a third calcite population 18o 9 1 to 16 9 precipitated from differentwaters at different temperatures that include present conditions calcites which could have been precipitated during present conditions mostly originate from open fissures

eastern tropical pacific hydrologic changes during the past 27 000 years from d h ratios in alkenones 1 the tropical pacific plays a central role in the climate system by providing large diabatic heating that drives the global atmospheric circulation quantifying the role of the tropics in late pleistocene climate change has been hampered by the paucity of paleoclimate records from this region and the lack of realistic transient climate model simulations covering this period here we present records of hydrogen isotope ratios dd of alkenones from the panama basin off the colombian coast that document hydrologic changes in equatorial south america and the eastern tropical pacific over the past 27 000 years a and the past 3 centuries in detail comparison of alkenone dd values with instrumental records of precipitation over the past 100 a suggests that dd can be used as a hydrologic proxy on long timescales our records indicate reduced rainfall during the last glacial period that can be explained by a southward shift of the mean position of the intertropical convergence zone and an associated reduction of pacific moisture transport into colombia precipitation increases at 17 ka in concert with sea surface temperature sst cooling in the north atlantic and the eastern tropical pacific a regional coupled model forced by negative sst anomalies in the caribbean simulates an intensification of northeasterly trade winds across central america increased evaporative cooling and a band of increased rainfall in the northeastern tropical pacific these results are consistent with the alkenone sst and dd reconstructions that suggest increasing precipitation and sst cooling at the time of heinrich event 1

adjustment of the coupled ocean atmosphere system to a sudden change in the thermohaline circulation 1 the adjustment of the coupled ocean atmosphere system to a fresh water anomaly in the north atlantic ocean is investigated using a coupled gcm in response to the anomaly the atlantic thermohaline circulation thc collapses and the associated reduction in northward heat transport causes sea surface temperatures sst to fall over the north atlantic and to increase over the tropical south atlantic atmospheric feedbacks are excited as soon as the sst anomalies reach sufficient magnitude a key stage in the adjustment process occurs 4 6 years after the perturbation is introduced when a significant sst dipole develops in the tropical atlantic this dipole causes a southward shift of the itcz and leads in year 7 to the triggering of an el nino event it is concluded that atmospheric feedbacks could spread globally the influence of a sudden change in the thc much more quickly and efficiently than could ocean processes alone

the high pco2 caprese reservoir northern apennines italy relationships between present and paleo fluid geochemistry and structural setting abstract the chemical and isotopic compositions of i co2 rich fluids exploited from the 5 000 m deep pieve santo stefano 1 pss1 borehole located in the upper tiber basin northern apennines italy and ii natural gas seeps located in its surroundings mainly in the mt fungaia ophiolitic bearing complex ligurian unit are presented and discussed deep seismic profiles have allowed to identify a thrust related antiform caprese antiform a regional geological structure trapping the pressurized deep fluids fluids from the caprese reservoir cr consist of a co2 n2 rich gas phase sourced by both mantle degassing and thermal degradation of carbonate rocks and organic rich sediments of the umbro tuscan sedimentary series and a na cl saline up to 82 g l of tds brine gases naturally discharging in the study area are related to those present in the cr these gases during their uprising toward the surface mix with shallow aquifers addition of i h2 and h2s derived by the interaction with ophiolite bearing ligurian units and ii thermogenic hydrocarbons originated from the degradation of organic matter contained in the turbiditic sandstone rich formations cervarola falterona unit was also evidenced fluid inclusions trapped in calcite and quartz crystals from the pss1 drill core at the depth of 3864 to 3867 m contain co2 n2 and h2o nacl phases the different paleo co2 n2 contents and densities found with respect to the fluids currently exploited from the cr have been related to the evolution of the reservoir throughout the time compositional data of fluids exploited from pss1 borehole provide a unique opportunity to better characterize chemical physical processes and source regions of past and present deep fluids circulating in northern apennines

reply to comment by g etiope and g martinelli pieve santo stefano is not a mud volcano comment on structural controls on a carbon dioxide driven mud volcano field in the northern apennines

impact of the atlantic multidecadal oscillation on north pacific climate variability 1 in this paper we found that the atlantic multidecadal oscillation amo can contribute to the pacific decadal oscillation pdo especially the component of the pdo that is linearly independent of el nino and the southern oscillation enso i e the north pacific multidecadal oscillation npmo and the associated pacific north america pna pattern using a hybrid version of the gfdl cm2 1 climate model we show that the amo provides a source of multidecadal variability to the north pacific and needs to be considered along with other forcings for north pacific climate change the lagged north pacific response to the north atlantic forcing is through atmospheric teleconnections and reinforced by oceanic dynamics and positive air sea feedback over the north pacific the results indicate that a north pacific regime shift opposite to the 1976 77 shift might occur now a decade after the switch of the observed amo to a positive phase around 1995 citation zhang r and t l delworth 2007 impact of the atlantic multidecadal oscillation on north pacific climate variability geophys res lett 34 l23708

evidence of fracturing and fluid movements in granite from finnsjon sweden derived from inclusions in fracture filling calcite and prehnite abstract fluid inclusions in fracture fillings in a red homogeneous granite at finnsjon sweden indicate a complex history of fracturing and infilling dissolution and redeposition in the last calcite phase three events of fluid activation were documented in the fractures 1 deposition at 80 c from a solution with 17 eq wt nacl 2 deposition at 135 c from 3 4 eq wt nacl solution 3 deposition or rehealing at 100 c or lower from a fresh to brackish water solution the inclusions frequently display metastable behavior with regard to vapor phase nucleation indicating that formation at a low temperature may be a dominant event this could mean deposition from alternately a circulated seawater and a subsurface brine the fractures may have been active quite recently as shown by low temperature freshwater inclusions and tectonic textures

dynamical links between the decadal variability of the oyashio and kuroshio extensions abstractrather than a single and continuous boundary current outflow long term satellite observations reveal that the oyashio extension oe in the north pacific subarctic gyre comprises two independent northeast southwest slanted front systems with a mean latitude along 40 n the western oe front exists primarily west of 153 e and is a continuation of the subarctic gyre western boundary current the eastern oe front also appearing along 40 n is located between 153 and 170 e whose entity is disconnected from its western counterpart during 1982 2016 both of the oe fronts exhibit prominent decadal fluctuations although their signals show little contemporaneous correlation an upper ocean temperature budget analysis based on the estimating the circulation and climate of the ocean phase ii ecco2 state estimate reveals that the advective temperature flux convergence plays a critical role in determining the low frequency temperature changes relating to the oe fronts specifically the western oe f

brittle tectonothermal evolution in the forsmark area central fennoscandian shield recorded by paragenesis orientation and 40ar 39ar geochronology of fracture minerals in this paper we show how studies of fracture mineral paragenesis their orientation and ar 40 ar 39 geochronology can be applied in order to recognise the brittle tectonothermal evolution in an area samples were selected from nearly 18 km of drill cores from the upper i km of the fennoscandian shield obtained during the site investigation for a repository of spent nuclear fuel in forsmark central sweden four major events of fracturing and or reactivation of fractures associated with fracture mineralisation have been distinguished the first event was characterised by precipitation of epidote quartz and chlorite along preferably sub horizontal and gently dipping fractures or steep wnw ese to nw se fractures precipitation occurred between 1 8 and 1 1 ga possibly during the late stage of the svecokarelian orogeny close to 1 8 1 7 ga the second event is associated with precipitation of hematite stained adularia and albite prehnite laumontite calcite and chlorite preferably along steep ene wsw to nne ssw and nnw sse fractures precipitation occurred around 1107 7 to 1034 3 ma probably due to effects from the sveconorwegian orogeny this event was followed by a period with dissolution of fracture minerals and subsequent precipitation of mainly calcite quartz pyrite and asphaltite during the palaeozoic the formation fluid emanated from an overlying organic rich sedimentary cover precipitation occurred during reactivation of proterozoic fractures but formation of new fractures is also inferred possibly due to far field effects of the caledonian orogeny or elevated hydrostatic pressure due to its foreland basin the latest event is dominated by clay minerals chlorite and calcite along hydraulically conductive fractures these minerals are prominent along sub horizontal and gently dipping fractures but also occur in sets of steeply dipping fractures it is inferred that the hydraulically conductive fractures are proterozoic structures in which mineral precipitation has occurred during a long period however some of the near surface sub horizontal fractures may be quaternary in age c 2009 elsevier b v all rights reserved less

the subarctic frontal zone in the north pacific characteristics of frontal structure from climatological data and synoptic surveys the subarctic front is a thermohaline structure across the north pacific separating colder fresher water to the north from warmer saltier water to the south levitus s 1982 data and 72 conductivity temperature depth salinity temperature depth sections are used to show the spatial and seasonal variations of the climatological frontal zone and the characteristics of the frontal structure in synoptic surveys the temperature gradient in the mean frontal zone is stronger in the western pacific and decreases eastward while the salinity gradient has less variation across the pacific the temperature gradient also has larger seasonal variation with a maximum in spring than the salinity gradient the synoptic surveys show that the frontal zone is narrower and individual fronts tend to be stronger in the western pacific than in the eastern pacific density gradients tend to be more compensated at the strongest salinity fronts than at the strongest temperature fronts a horizontal minimum of vertical stability is found south of the subarctic halocline outcrop the northern boundary of the north pacific intermediate water merges with the frontal zone west of 175 w and is north of the northern boundary of the subarctic frontal zone in the eastern pacific the shallow salinity minima start within the subarctic frontal zone in the eastern pacific

a low angle normal fault in the umbria region central italy a mechanical model for the related microseismicity abstract in the northern apennines the upper crust is thinned by a set of east dipping low angle normal faults lanfs the easternmost and more recent of these lanfs is the altotiberina fault atf located in northern umbria the geometry of the atf has been reconstructed matching surface geology with seismic reflection profiles and borehole data the fault whose average dip is 20 borders the upper pliocene quaternary tiber basin and has a displacement of about 8 km the deeper portion of the atf is located below the axial zone of the northern apennines where the strongest instrumental and historical seismicity is recorded the microseismicity of the region m 1 to evaluate the boundary conditions for the brittle activity of the atf the fault can be reactivated for low values of differential stress 1 3 t 10 mpa and tensile fluid overpressure p f 3 e g v 0 93 in the peculiar situation of the northern apennines the deep emissions of large amounts of co 2 documented in the area can be entrapped in their ascent by structural seals e g atf favouring localised fluid overpressures the impossibility of sustaining p f 3 for wide fault portions counteracted by hydraulic fracturing increased permeability under low effective stress and load weakening behaviour for normal faulting would prevent the nucleation of moderate ruptures along the fault the short lived attainment of p f 3 along small fault portions can account for the microseismic activity located along the atf which occurs on rupture surfaces in the range of 10 1 10 3 km 2

on the seasonal variability of the oyashio extension fronts previous study reported that the annual mean eastern oyashio extension oe front shifts northward while the western oe front has no obvious poleward shift during 1982 2017 by wu et al geophys res lett 45 9042 9048 2018 here we revisit this topic and focus on the seasonal variability and shifts of the oe fronts from 1982 to 2018 with observational reanalysis data and a 1 5 layer reduced gravity model simulation in winter both the western and eastern oe fronts demonstrate consistent northward movement while in summer the eastern oe front still moves northward but the western oe front has no obvious and even southward shift it is shown that the trade wind s expansion during 1982 2018 favours the northward shift of the oe fronts for both winter and summer however there is a local cold ekman heat transport anomaly along the western oe front in summer which surpasses the effect of trade wind expansion and prohibits northward movement of the front this cold ekman advection is due to a westerly wind anomaly induced firstly by the atlantic multi decadal oscillation amo and secondly by the pacific decadal oscillation pdo in winter the local ekman heat transport is less effective than in summer in changing the oe front position because of the deep mixed layer our study demonstrates the seasonality of the oe front shift and highlights the importance of local ekman heat transport associated with the amo our results also partly explain the rainfall changes in both winter and summer in the western pacific ocean in the past 37 years since the rainband east of japan is affected by the sea surface temperature and its front

decadal variability of the kuroshio extension observations and an eddy resolving model hindcast abstract low frequency variability of the kuroshio extension ke is studied using observations and a multidecadal 1950 2003 hindcast by a high resolution 0 1 eddy resolving global ocean general circulation model for the earth simulator ofes in both the ofes hindcast and satellite altimeter observations low frequency sea surface height ssh variability in the north pacific is high near the ke front an empirical orthogonal function eof analysis indicates that much of the ssh variability in the western north pacific east of japan is explained by two modes with meridional structures tightly trapped along the ke front the first mode represents a southward shift and to a lesser degree an acceleration of the ke jet associated with the 1976 77 shift in basin scale winds the second mode reflects quasi decadal variations in the intensity of the ke jet both the spatial structure and time series of these modes derived from the hindcast are in close agreement with observations a linear rossby wave

interdecadal decrease of the oyashio transport on the continental slope off the southeastern coast of hokkaido japan we investigated the interdecadal trend of oyashio velocity and transport during 1993 2011 based mainly on linear trend analysis of altimetry and in situ temperature salinity data from a monitoring line a line off the southeastern hokkaido coast significant trends of increasing sea level were detected on the continental slope north of the kuril kamchatka trench sea level anomaly data revealed a localized clockwise circulation centered near the trench the suggestion being that the strength of the oyashio on the slope and the offshore return flow had decreased the oyashio mainstream seemed to have shifted from a nearshore to an offshore path steric heights estimated from the a line data exhibited an increasing trend north of the trench where 50 80 of the increase was determined by halosteric components attributable to a trend of decreasing salinity in the subsurface the trend of decreasing salinity was related to downward displacement of isohaline isopycnal surfaces the largest displacement was above the trench horizontal pressure gradients associated with southwestward flows on the slope were weakened the oyashio transport decreased by 8 9 sv 106 m3 s 1 in 19 years a mesoscale eddy analysis revealed that clockwise eddies appeared more frequently in recent years near the trench around the a line and could decrease the oyashio transport a baroclinic long rossby wave model also predicted that a large scale baroclinic response to the wind stress could weaken the oyashio velocity in the upper layer dynamical linkage between the localized eddies and large scale response remains to be clarified in future work

looking at fault reactivation matching structural geology and seismological data abstract we investigate fault reactivation that occurred during the 1997 colfiorito seismic sequence central italy matching detailed structural geology precise earthquake locations and mechanical models of fault interaction the colfiorito area within the northern apennines is characterised by a relatively recent inversion of the tectonic stress field from compression late miocene to extension late pliocene quaternary in september october 1997 the area experienced a protracted seismic sequence consisting of six moderate magnitude earthquakes 5 we analyse the coseismic elastic static stress changes due to the occurrence of the normal fault events in order to investigate the mechanical coupling and interaction between the nw se oriented normal fault system and the intervening n10 inherited fault we show that the elastic stress perturbation increased on the shallow portion of the activated volume where the n10 structure is located and promoted its reactivation with a strike slip motion the different amount of slip experienced along the two normal faults responsible for the greater mainshocks favoured the left lateral strike slip kinematics

on the relationship between tropical and north pacific sea surface temperature variations abstract empirical orthogonal function analysis of winter sea surface temperature sst anomalies over the pacific domain 60 n 20 s reveals an el nino southern oscillation enso mode that is linked to the eastern north pacific and a north pacific mode that is linearly independent of enso the north pacific mode exhibits maximum amplitude and variance explained along 40 n west of 170 w ssts in this region have decreased by 1 5 c from 1950 to 1987 the cooling in winter has been associated with a strengthening of the overlying westerly winds

a review and comparison of fracture mineral investigations and their application to radioactive waste disposal abstract a compilation and comparison of fracture mineral studies from the canadian and fennoscandian shields and the french massif central shows many similarities indicating larger external control over fracture mineral deposition with different rock types exerting local controls the sites investigated represent a wide range of geological settings and host rock types ranging from felsic intrusive and extrusives to ultramafic intrusives and volcanics that span an age range from 2 5 to 0 36 ga typical fracture minerals found at canadian shield sites include calcite quartz chlorite and clays and these do not appear to be dependant on age erosional depth or geological environment the fennoscandian shield has a much larger variety of fracture filling minerals with epidote zeolites prehnite fluorite pyrrhotite fe oxides serpentine graphite magnesite and barite in addition to the minerals typically found at canadian shield sites the major control on fracture mineral type is most likely variations in rock type and fluid chemistry and temperature the c and o isotopic range of calcite is very similar among sites late stage hydrothermal calcite with strongly depleted 18o values is common at many sites all of the sites have calcite with 18o isotopic values in the range of 5 to 20 pdb indicative of formation from meteoric water or basinal brines that have undergone varying degrees of water rock interaction one canadian and a few swedish sites have calcite in the shallower portion of the rock that shows isotopic evidence of dissolution and re precipitation in equilibrium with the present day waters there are some striking similarities in fluid inclusion data among sites most sites have an elevated temperature 100 300 c low salinity group of fluid inclusions within the nacl h2o system and a lower temperature 50 150 c higher salinity group of fluid inclusions within the nacl cacl2 h2o system fluid inclusion density plots show some evidence of simple cooling but most sites show two or more fluids were responsible for calcite formation the origin of most of these fluids was magmatic hydrothermal or meteoric water that had undergone varying degrees of water rock interaction but basinal brines and seawater were also possible sources several techniques and methods have been used to further characterize calcites strontium isotopes and rare earth elements can be useful to recognize different families of calcite uranium th dating has found many old calcites beyond the useful range of the technique but also some relatively young calcites that may be related to interglacial periods where fluid inclusion data exists formation temperatures were not consistent with a glacial water origin crush and leach experiments with ion and gas chromatography and thermal ion mass spectrometry have characterized inclusion fluids but special care must be used to ensure only one generation is sampled at a time cathodoluminescence and scanning electron microscopy with energy dispersive spectrometry has been useful in identifying multiple fluid generations within single calcite samples laser ablation and raman spectrometry are additional techniques that are useful in determining individual fluid inclusion chemistry and isotopes

characterization of stress perturbations near major fault zones insights from 2 d distinct element numerical modelling and field studies jura mountains abstract we consider and discuss the presence of discontinuities in the crust as a major source of stress perturbations based on 2 d distinct element modelling we reconstruct the local stress field around a vertical discontinuity in various geological contexts the resulting stress distribution reveals that major directional stress changes occur near the tips of the discontinuity so that stress deviations can reach values as large as 50 we establish simple relationships controlling stress changes around a pre existing fault zone as a function of 1 the remote differential stress magnitude 1 3 2 the friction coefficient on the discontinuity and 3 the strike of the discontinuity relative to the far field stress as a geological example we present the morez fault zone in the internal jura paleostress reconstruction in forty two sites indicates that the trends of the mio pliocene compression are n110 on average near the fault whereas they are n130 in the surrounding areas a comparison between the results of the tectonic study and those of theoretical modelling suggests that the 20 counterclockwise deviation is directly related to the reactivation of this large weak zone we thus evaluate the role of mechanical decoupling along pre existing zones of weakness especially with consideration to the accommodation of the alpine deformation in the jura belt

structural controls on a carbon dioxide driven mud volcano field in the northern apennines pieve santo stefano italy relations with pre existing steep discontinuities and seismicity the strong release of carbon dioxide co2 rich fluids in the axial zone of the northern apennines near pieve santo stefano is analysed in relation to both structural controls and the microseismicity that followed the earthquake of 26 november 2001 some vents recorded a transition from gas dominated emission to post seismic mud extrusion the co seismic rupture of a portion of the nw trending alto tiberina fault which bounds the quaternary upper tiber basin presumably broke the hydraulic seal trapping overpressured co2 rich fluid compartments and released a fluid pressure pulse fault pattern analysis has revealed that venting localises along ne trending steep faults associated with the regional transverse arbia val marecchia line bounding the basin to the northwest it is proposed that the transverse faults have been acting as permeable pathways allowing the post seismic transport of overpressured fluids to the surface during which the mud was mobilised a hypothetical correlation is also established between failure mechanisms and the 2001 aftershocks results of mohr constructions indicate that frictional fault reactivation is a suitable mechanism for explaining the seismic events along the nw trending normal fault while hydraulic fracturing is the most suitable to describe the seismicity occurring along the transverse faults

interdecadal variability of the pacific ocean model response to observed heat flux and wind stress anomalies variability of the pacific ocean is examined in numerical simulations with an ocean general circulation model forced by observed anomalies of surface heat flux wind stress and turbulent kinetic energy tke over the period 1970 88 the model captures the 1976 77 winter time climate shift in sea surface temperature as well as its monthly seasonal and longer term variability as evidenced in regional time series and empirical orthogonal function analyses examination of the surface mixed layer heat budget reveals that the 1976 77 shift was caused by a unique concurrance of sustained heat flux input anomalies and very strong horizontal advection anomalies during a multi month period preceding the shift in both the central pacific region where cooling occurred and the california coastal region where warming occurred in the central pacific the warm conditions preceding and the cold conditions following the shift tend to be maintained by anomalous vertical mixing due to increases in the atmospheric momentum flux tke input into the mixed layer which deepens in the model after the shift from the early 1970s to the late 1970s and 1980s since the ocean model does not contain feedback to the atmosphere and it succeeds in capturing the major features of the 1976 77 shift it appears that the midlatitude part of the shift was driven by the atmosphere although effects of midlatitude ocean atmosphere feedback are still possible the surface mixed layer heat budget also reveals that in the central pacific the effects of heat flux input and vertical mixing anomalies are comparable in amplitude while horizontal advection anomalies are roughly half that size in the california coastal region in contrast where wind variability is much weaker than in the central pacific horizontal advection and vertical mixing effects on the mixed layer heat budget are only one quarter the size of typical heat flux input anomalies

reply to comment by c collettini on structural controls on a carbon dioxide driven mud volcano field in the northern apennines pieve santo stefano italy relations with pre existing steep discontinuities and seismicity