identification of permian palaeowind direction from wave dominated lacustrine sediments lodeve basin france lacustrine environments are an excellent indicator of continental palaeoclimate in particular the sedimentary record of waves in lakes may be used to constrain atmospheric palaeocirculation wave ripples have been identified in a permian lacustrine basin the salagou formation 260 250 ma lodeve basin located in the southern french massif central part of the western european hercynian mountain chain wave ripple patterns are interpreted with regards to hydrodynamics and water palaeodepth it is shown that in the case of the salagou formation wave ripple orientations were controlled by the direction of the prevailing palaeowind the late permian wind blew from between north and 20 east of north possibly over several millions of years and certainly throughout the period of deposition of about 2000 m of strata in the lodeve basin permian lacustrine sedimentation is widespread and well preserved on the earth s surface and so wave ripple data may help constrain numerical modelling of the earth s past climates especially with regards to permian times outside of desert regions

is there evidence for magmatic underplating beneath the oslo rift we challenge some of the long standing beliefs related to the permian oslo rift structure often referred to as a case example type locality for continental rifting the crustal structure of the oslo rift was long presumed to be thinned proterozoic crust overlying a permian high density layer interpreted as magmatic underplating new data support an alternative view of the crustal structure in the oslo rift region the bouguer gravity high in the region shows a strong asymmetry a steep westward facing gradient to the west of the rift and a much gentler eastern gradient we present a 3d density model based on petrophysical and seismic information which accounts for the bouguer gravity high using an eastward extension of old precambrian structures without invoking a prominent magmatic underplated structure reactivation of old pre rift structures appears to be an important feature affecting the evolution and location of the permo carboniferous oslo rift

real time reliable magnitudes for large earthquakes from 1 hz gps precise point positioning the 2011 tohoku oki japan earthquake 1 the early warning issued after the onset of the mw9 0 tohoku oki earthquake significantly underestimated its magnitude saturating 120 seconds after the earthquake began at mw8 1 here we investigate whether real time deformation data from japan s dense network of continuously recording global positioning system gps stations could have been used to provide a more reliable rapid estimate of the earthquake s magnitude and ultimately a more robust tsunami forecast we use precise point positioning in real time mode with broadcast clock and orbital corrections to give station positions every 1 s we then carry out a simple static inversion on a subset of stations to determine the portion of the fault that slipped and the earthquake magnitude unlike most previous methods our method produces estimates of seismic moment before the earthquake rupture has completed we find that the deformation data allow a robust magnitude estimate just 100 s after the earthquake onset we also investigated the density of stations required for a robust moment magnitude estimate fewer than 1 station every 100 km are needed we recommend that gps data be incorporated into earthquake early warning systems for regions at threat from large magnitude earthquakes and tsunamis

a threshold based earthquake early warning system for offshore events in southern iberia the south of the iberian peninsula is situated at the convergence of the eurasian and african plates this region experiences large earthquakes with long separation in time the best known of which was the great 1755 lisbon earthquake which occurred sw of san vicente cape sw iberian peninsula the high risk of damaging earthquakes has recently led carranzaet al geophys res lett 40 2013 to investigate the feasibility of an eews in this region analysis of the geometry for the iberian seismic networks and the san vicente cape area led the authors to conclude that a threshold based approach which would not require real time location of the earthquake might be the best option for an eews in sw iberia in this work we investigate this hypothesis and propose a new eew approach that extends standard p wave threshold based single station analysis to the whole network the proposed method enables real time estimation of the potential damage at stations that are triggered by p waves and those which are not triggered with the advantage of greater lead times for release of alerts results of tests made with synthetic data mimicking the scenario of the great 1755 lisbon earthquake and those conducted by applying the new approach to available recordings indicate that an eew estimation of the potential damage associated with an event in the san vicente cape area can be obtained for a very large part of the iberian peninsula

seismogeodetic p wave amplitude no evidence for strong determinism whether the final properties of large earthquakes can be inferred from initial observations of rupture deterministic rupture is valuable for understanding earthquake source processes and is critical for operational earthquake and tsunami early warning initial p wave characteristics of small to moderate earthquakes scale with magnitude yet observations of large to great earthquakes saturate resulting in magnitude underestimation whether saturation is inherent to earthquake dynamics or rather is due to unreliable observation of long period signals with inertial seismic instrumentation is unclear seismogeodetic methods are better suited for broadband observation of large events in the near field in this study we investigate the deterministic potential of seismogeodetically derived p wave amplitude using a dataset of 14 medium to great earthquakes around japan our results indicate that seismogeodetic p wave amplitude is not a reliable predictor of magnitude opposing the notion of strong determinism in the first few seconds of rupture

late variscan tectonic evolution by thinning of earlier thickened crust an 40ar39ar study of the montagne noire southern massif central france abstract 40ar 39ar age determinations on samples selected on deformational criteria form the basis of a proposal of a new detailed tectonometamorphic history of the montagne noire the southern part of the massif central france this range is classically divided into a cover and an axial gneissic and migmatitic core which was metamorphosed under high t medium p conditions the basement is structurally overlain by epimetamorphic paleozoic sediments in the north in the south equivalent rocks form a well known pile of recumbent nappes the variscan history of this area comprises early shortening and thickening of the continental crust the climax of this event took place around 320 ma ago as is shown by previous rb sr data and by 40ar 39ar measurements new developments in structural analyses have led to a better understanding of the late evolution of the area in terms of diapiric uplift of the core south southwestwards verging recumbent nappes have been emplaced and were weakly metamorphosed in their lower parts this movement was accompanied and followed by dextral extensional wrenching of the paleozoic cover along the northern and southern margins of the axial zone attendantly ductile shear zones were formed in order to decipher the complex history three structural levels have been dated with the 40ar 39ar method these levels are 1 the migmatitic and gneissic series in the axial core where micas yield ages of c 315 ma 2 mylonites from the northern and southern shear zones where biotites and muscovites yield ages of c 310 ma 3 muscovites and biotites from the epimetamorphic nappe structures yielding ages of c 297 ma the later ages may represent a younger thermal pulse these data are compared and discussed in the light of previous radiometric studies of the area and precise biostratigraphic constraints a detailed geodynamic evolution of the studied segment is proposed

tectonics and magmatism in turkey and the surrounding area this volume contains 23 papers from a range of international contributors describing recent research into the tectonics and magmatism of turkey and its surroundings this region is sited at the collision zone between eurasia and afro arabia and as such provides an extraordinarily complete and well exposed record of the staged tectonic evolution of this sector of the alpine himalayan orogen the geological history of this area involves separation of continental fragments from the margin of gondwana their migration across the tethyan oceans the subsequent closure of these oceans and finally the development of the neotectonic regime which continues to evolve to the present day such a comprehensive record is relevant to the understanding of collisional zones worldwide the volume is divided into five sections tethyan evolution neotethyan ophiolites post tethyan basin evolution neotectonics and igneous activity the first two sections deal with tethyan oceans whose growth and subsequent closure dominated the geodynamic framework in the mesozoic and cenozoic the subsequent sections deal with more recent geological developments from the balkan peninsula in the west to the transcaucasus in the east that followed consumption of the tethyan oceans there is a broad mix of papers throughout the volume wide ranging review papers on ocean development and extensional tectonics are followed by detailed descriptions of petrology and geochemistry and geographically focused studies on basin evolution specific aspects of extensional and strike slip tectonics and discussions of the relationship of magmatic activity to the tectonic development of the area tectonics and magmatism in turkey and the surrounding area presents up to date results and ideas from a large number of international contributors on a wide range of current research activity in this region it is essential reading for all geoscientists with an interest in both academic and applied aspects of eastern mediterranean geology

microbial colonization of halite from the hyper arid atacama desert studied by raman spectroscopy the hyper arid core of the atacama desert chile is the driest place on earth and is considered a close analogue to the extremely arid conditions on the surface of mars microbial life is very rare in soils of this hyper arid region and autotrophic micro organisms are virtually absent instead photosynthetic micro organisms have successfully colonized the interior of halite crusts which are widespread in the atacama desert these endoevaporitic colonies are an example of life that has adapted to the extreme dryness by colonizing the interior of rocks that provide enhanced moisture conditions as such these colonies represent a novel example of potential life on mars here we present non destructive raman spectroscopical identification of these colonies and their organic remnants spectral signatures revealed the presence of uv protective biomolecules as well as light harvesting pigments pointing to photosynthetic activity compounds of biogenic origin identified within these rocks differed depending on the origins of specimens from particular areas in the desert with differing environmental conditions our results also demonstrate the capability of raman spectroscopy to identify biomarkers within rocks that have a strong astrobiological potential

miniaturized raman instrumentation detects carotenoids in mars analogue rocks from the mojave and atacama deserts this study is primarily focused on proving the potential of miniaturized raman systems to detect any biomolecular and mineral signal in natural geobiological samples that are relevant for future application of the technique within astrobiologically aimed missions on mars a series of evaporites of varying composition and origin from two extremely dry deserts were studied namely atacama and mojave the samples represent both dry evaporitic deposits and recent evaporitic efflorescences from hypersaline brines the samples comprise halite and different types of sulfates and carbonates the samples were analysed in two different ways i directly as untreated rocks and ii as homogenized powders two excitation wavelengths of miniaturized raman spectrometers were compared 532 and 785 nm the potential to detect carotenoids as biomarkers on mars compared with the potential detection of carbonaceous matter using miniaturized instrumentation is discussed

reply to comment by p rydelek et al on earthquake magnitude estimation from peak amplitudes of very early seismic signals on strong motion records 1 based on the analysis of mediterranean near source strong motion records zollo et al 2006 hereinafter referred to as zln showed that peak displacement amplitudes of initial pand s wave seismic signals scales with the earthquake size in the moment magnitude range 4 6 1 9 in figure 1 we report data distribution vs magnitude and hypocentral distance note that the distance distribution of analyzed events for japan figure 1 is clearly different from that for the mediterranean med earthquakes given by zln whereas most of med records occur at an hd 40 km 10 at odds with rwh we did not apply any cut off at m 5 5 on hypocentral distance for small and moderate events indeed this may introduce a bias on the estimation of attenuation law parameters retrieved from both small and large earthquakes records we follow the zln procedure involving among others sensitivity correction p and s phase identification double integration filtering in a frequency band 0 075 3 hz peaks are read on the modulus of displacement expressed in meters starting from the pwave and s wave picked arrivals we measure peaks within a 2 second window for the p arrival we also test the method with 4 second windows 11 the distance attenuation effect is corrected for by assuming a simple log linear model wu and zhao 2006 zln the amplitudes are normalized to a reference distance of 10 km i e the same as for zln in the mediterranean study to facilitate comparison though rwh show data normalized at a distance of 20 km zln figures 2a and 2b the use of a different normalization distance does not change the slope of the log peak vs magnitude relationships and thus does not alter the graphical interpretation 12 in figure 2 we show the relation between the logarithm of distance normalized peak displacement for p and s waves in different time windows vs final magnitude of the events following zln statistical significance was geophysical research letters vol 34 l20303 doi 10 1029 2007gl030560 2007 click here for full article

hypersaline wet patches in taylor valley antarctica 1 spatially isolated patches of soil located in taylor valley mcmurdo dry valleys antarctica are sites of elevated salt content and soil moisture during antarctic spring in the absence of snow melt visibly wet reduced albedo patches of soil are present at the surface the soil pore fluids are hypersaline and have average water activity of 0 74 the water activity of a solution determines the equilibrium vapor pressure of that solution and are an order of magnitude more saline than average soils in the dry valleys these salty soils are 3 5 times more water rich than average soils geochemical and meteorological analyses show that these wet patches are sites of direct vapor emplacement into soil pore fluids that may ultimately be sourced by the deliquescence of soil salts these wet patches represent a non precipitation non groundwater source for water into antarctic permafrost

chronostratigraphy and paleoclimatology of the lodeve basin france evidence for a pan tropical aridification event across the carboniferous permian boundary abstract paleosols preserved within the carboniferous permian succession of the lodeve basin massif central france change stratigraphically from histosols to calcic vertisols and calcisols to gypsic vertisols and ultimately back to calcic vertisols and calcisols new high precision u pb zircon ages ca idtims for tuff beds within the lodeve and adjacent graissessac basins significantly revise the chronostratigraphy of these and correlated permian terrestrial basins of eastern euramerica under the newly revised chronostratigraphy presented here these stratigraphic changes in morphology indicate a substantial drying of paleoenvironments across the carboniferous permian boundary with a trend toward progressively more arid and seasonal climates through most of the early permian this newly realized chronology provides a paleoenvironmental and paleoclimatic timeline for eastern tropical pangea that is contemporaneous with similar records in western pangea and suggests pan tropical progressive climate change toward aridity and seasonality occurred from the late carboniferous through early permian

the lithobiontic ecological niche with special reference to microorganisms abstract revised terminology is proposed that describes the ecological niches of microorganisms within hard mineral substrates organisms attached to the external surfaces of the rock are termed epiliths while those in the interior of the rock are all termed endoliths the latter are called chasmoendoliths if they inhabit fissures in rocks cryptoendoliths if they dwell within structural cavities and euendoliths if they actively penetrate calcareous substrates

shallow dynamic overshoot and energetic deep rupture in the 2011 mw 9 0 tohoku oki earthquake strong spatial variation of rupture characteristics in the moment magnitude mw 9 0 tohoku oki megathrust earthquake controlled both the strength of shaking and the size of the tsunami that followed finite source imaging reveals that the rupture consisted of a small initial phase deep rupture for up to 40 seconds extensive shallow rupture at 60 to 70 seconds and continuing deep rupture lasting more than 100 seconds a combination of a shallow dipping fault and a compliant hanging wall may have enabled large shallow slip near the trench normal faulting aftershocks in the area of high slip suggest dynamic overshoot on the fault despite prodigious total slip shallower parts of the rupture weakly radiated at high frequencies whereas deeper parts of the rupture radiated strongly at high frequencies

an empirical evolutionary magnitude estimation for early warning of earthquakes abstract the earthquake early warning eew system is difficult to provide consistent magnitude estimate in the early stage of an earthquake occurrence because only few stations are triggered and few seismic signals are recorded one of the feasible methods to measure the size of earthquakes is to extract amplitude parameters using the initial portion of the recorded waveforms after p wave arrival however for a large magnitude earthquake m w 7 0 the time to complete the whole ruptures resulted from the corresponding fault may be very long the magnitude estimations may not be correctly predicted by the initial portion of the seismograms to estimate the magnitude of a large earthquake in real time the amplitude parameters should be updated with ongoing waveforms instead of adopting amplitude contents in a predefined fixed length time window since it may underestimate magnitude for large magnitude events in this paper we propose a fast robust and less saturated approach to estimate earthquake magnitudes the eew system will initially give a lower bound of the magnitude in a time window with a few seconds and then update magnitude with less saturation by extending the time window here we compared two kinds of time windows for measuring amplitudes one is p wave time window ptw after p wave arrival the other is whole wave time window after p wave arrival wtw which may include both p and s wave one to ten second time windows for both ptw and wtw are considered to measure the peak ground displacement from the vertical component of the waveforms linear regression analysis are run at each time step 1 to 10 s time interval to find the empirical relationships among peak ground displacement hypocentral distances and magnitudes using the earthquake records from 1993 to 2012 in taiwan with magnitude greater than 5 5 and focal depth less than 30 km the result shows that considering wtw to estimate magnitudes has smaller standard deviation than ptw the magnitude estimations using 1 s time widow have larger uncertainties progressively adopting peak displacement amplitudes p d from 2 to 10 s wtw is suggested for eew systems

comment on earthquake magnitude estimation from peak amplitudes of very early seismic signals on strong motion records by aldo zollo maria lancieri and stefan nielsen an early warning system should determine the loca tion and magnitude of an earthquake as rapidly as possiblein order to broadcast an alarm to regions that will undergosevere ground shaking it was recently claimed by zollo etal 2006 that earthquake size could be determined fromonly the first 2 seconds of p or s wave strong motion data this represents a fraction of the rupture time for larger m 7 events using this relatively short amount of data themethod of analysis was to find the peak ground displace ment pgd which was reported to scale with earthquakemagnitude such rapid information would play an importantand much needed role in an earthquake early warning eew system here we perform a similar analysis onstrong motion data from the kik net and k net arrays injapan and find no compelling evidence that the peak grounddisplacement during the first couple of seconds of p wave isrelated to the eventual size of a large earthquake

late orogenic extension in mountain belts insights from the basin and range and the late paleozoic variscan belt from two examples of orogenic domains some general mechanisms significant of late orogenic tectonic processes in mountain belts are characterized the basin and range province and the variscan belt in the french massif central have both suffered important compressional orogenic crustal thickening and the results of late orogenic processes can be observed in the field both areas are covered by deep seismic profiling providing constraints on the geometry of a crust which has been restored to a normal thickness late orogenic features from the two domains are compared at different scales and their tectonic significance for extension mechanisms is discussed at the scale of the orogenic domains the most prominent tectonic features are the metamorphic core complexes mcc which expose deformed rocks from the middle crust generally affected by high temperature low to medium pressure metamorphism partial melting and widespread granite emplacement in these mcc large scale extensional shear zones present an intense mylonitic deformation characterized by low dipping foliations and pervasive stretching lineations they show a complete evolution from early deep seated ductile deformation generally achieved under high temperature low to medium pressure metamorphism to a late shallow brittle stage characterized by cataclastic deformation the late detachment stage generally controls the development of asymmetrical extensional sedimentary basins filled by continental deposits two main geometries of mcc are defined that are characterized by differing geometry and kinematics of low angle shear zones in the first case two low angle shear zones with opposite vergence develop along the flanks of a roughly symmetrical mcc often one system is dominant over the other the second geometry characterizes asymmetrical mcc bounded by a single normal shear zone which is upwarped during uplift and doming of the core caused by tectonic denudation detailed strain analysis performed in several extensional shear zones shows that the deformation regime is heterogeneous and results from general noncoaxial flow deformation along the shear zones evolves progressively from slight homogeneous pure shear strain to intense heterogeneous noncoaxial shear strain strain distribution within the lower crust is less well constrained by field observation however analogies between cocorp and ecors deep seismic reflection profiles give important constraints on crustal structure wide zones of highly subhorizontally layered lower crust and a flat high amplitude reflection moho characterize both evolved orogenic domains suggesting that major deformations and flow occur within the lower crust during extension a kinematic model involving heterogeneous crustal deformation and regional scale flow fits relatively well with late orogenic structures observed in continental domains a weak hot upper mantle allows large scale flow of lower crust material from zones of deep ductile extension to uplifted domains of upper crustal denudation heterogeneous strain is accommodated by low angle extensional shear zones from localized zones of extension in the brittle crust to ductile lower crust combined pure and simple shear occurs along localized shear zones whereas at the scale of the whole lithosphere deformation nearly corresponds to a vertical pure shear such deformation processes which affect a thick and hot crust seem to be common in both compared domains suggesting that late orogenic extensional processes are slightly dependent of the type of contractional tectonics thus as much in the andean type west american cordilleran belt as in the collision type variscan belt late orogenic processes produced similar extensional features

earthquake early warning for bucharest romania novel and revised scaling relations 1 the accumulation of strong earthquakes with resembling source mechanisms in the romanian vrancea zone se carpathians allows for designing a simple cheep and robust earthquake early warning eew system for bucharest with leading times of about 25 s a previously established scaling relation for eew predicts in the range from 1 2 s a ten times higher ground motion amplitude in bucharest than the maximum p wave acceleration measured in the epicentral area using additional weak and strong motion data we find that ground shaking in bucharest is generally overestimated by this relation by a factor of two however the predicted amplitudes are within the 95 confidence interval of our revised relation additional predictive laws for eew are determined for different ground motion parameters the application of our scaling relations to the october 27 2004 vrancea earthquake m w 6 0 supports the feasibility of the approach for eew in romania

self contained local broadband seismogeodetic early warning system detection and location earthquake and local tsunami early warning is critical to mitigating adverse impacts of large magnitude earthquakes an optimal system must rely on near source data to maximize warning time to this end we have developed a self contained seismogeodetic early warning system employing an optimal combination of high frequency information from strong motion accelerometers and low frequency information from collocated global navigation satellite systems gnss instruments to estimate real time displacements and velocities like gnss and unlike broadband seismometers seismogeodetic stations record the full waveform including static offset without clipping in the near field or saturating for large magnitude earthquakes however gnss alone cannot provide a self contained system and requires an external seismic trigger seismogeodetic stations detect p wave arrivals with the same sensitivity as strong motion accelerometers and thus provide a stand alone system we demonstrate the utility of near source seismogeodesy for event detection and location with analysis of the 2010 mw7 2 el mayor cucapah baja california and 2014 mw6 0 napa california strike slip events and the 2014 mw8 2 iquique chile subduction zone earthquake using observatory grade accelerometers and gps data we present lessons from the 2014 mw4 0 piedmont california and 2016 mw5 2 borrego springs california earthquakes recorded by our seismogeodetic system with micro electro mechanical system mems accelerometers and gps data and reanalyzed retrospectively we conclude that our self contained seismogeodetic system is suitable for early warning for earthquakes of significance m5 using either observatory grade or mems accelerometers finally we discuss the effect of network design on hypocenter location and suggest the deployment of additional seismogeodetic stations for the western u s

laboratory studies of perchlorate phase transitions support for metastable aqueous perchlorate solutions on mars abstract perchlorate salts recently discovered on mars are known to readily absorb water vapor from the atmosphere and deliquesce into the aqueous phase at room temperature here we study the deliquescence crystalline solid to liquid transition and efflorescence liquid to crystalline solid transition of perchlorate salts at low temperatures relevant to mars a raman microscope and environmental cell were used to determine the deliquescence relative humidity drh and efflorescence relative humidity erh of naclo 4 and mg clo 4 2 as a function of temperature and hydration state we find that the deliquescence of anhydrous naclo 4 is only slightly dependent on temperature and occurs at 38 rh the drh of naclo 4 h 2 o increases with decreasing temperature from 51 at 273 k to 64 at 228 k the drh of mg clo 4 2 6h 2 o also increases with decreasing temperature from 42 at 273 k to 64 at 223 k the efflorescence of both naclo 4 and mg clo 4 2 salt solutions occurs at a lower rh than deliquescence due to the kinetic inhibition of crystallization for all temperatures studied the erh values of naclo 4 and mg clo 4 2 are 13 and 19 respectively these results indicate perchlorate salts can exist as metastable supersaturated solutions over a wide range of rh and temperature conditions summer diurnal temperature and relative humidity cycles at low latitudes on mars could allow the surface salts to be aqueous for several hours per day

filling sequence in late paleozoic continental basins a chimera of climate change a new light shed given by the graissessac lodeve basin se france abstract the characteristics of sedimentary deposits in continental basins especially those controlled by extension are often used to infer global climatic changes we question the relevance of such an approach because the stratigraphic pattern of those basins are mostly similar whatever their latitudes paleolatitudes i e their general climatic conditions namely the transition from 1 an ancestral drainage network to 2 deep lake with a dominance of black and grey shale deposits 3 shallow oxic lake with a dominance of red pelites deposits and to eventually 4 a new drainage network such transitions observed in late palaeozoic continental basins throughout laurasia and gondwana are generally interpreted as evidence of global change from a wet climate to an arid climate from the sedimentological and structural analysis of a late palaeozoic basin the graissessac lodeve basin in the south of the variscan french massif central we proposed a new tectono stratigraphic sequence of this basin from the late carboniferous to the early trias we estimate the paleo area from 295 450 km 2 to 880 1150 km 2 of the basin and we deduce a subsidence curve from the late carboniferous to the late permian from 600 200 m my to 100 10 m my we conclude that the graissessac lodeve basin stratigraphic pattern corresponds to a classical continental rift sequence controlled by tectonics in order to assess a possible control of the stratigraphic sequence by the climate we have reconstructed the paleo depth of the lake with 1 the morphometric analysis of the wave ripples and 2 with an estimation of the lacustrine slope considering the tectonic origin of the lake we find that the maximum lacustrine depth has evolved from a range of 80 300 m during the late carboniferous to 40 45 m during the late permian from our estimates of the different configurations of the basin we show that the volume of the water in the lake has remained nearly constant between 10 and 30 km 3 from the late carboniferous 300 my to the late permian 250 my eventually we conclude that the sedimentological indicators of shallowing and episodic drying observed from the late carboniferous to late permian in this basin and probably in all the pangea basins of the same type are the consequence of the basin enlargement by tectonics and its sedimentary filling rather than climatic change

development of an earthquake early warning system based on earthworm application to southwest iberia abstract the main aim of this study is to demonstrate the feasibility of an earthquake early warning system eews to warn of potentially destructive earthquakes in the cape san vicente sv and gulf of cadiz gc areas in the southwest iberian peninsula based on real time broadband stations existing in the region historic earthquakes in this region include the 1755 lisbon m w 8 5 and 1969 sv m w 7 8 events this study illustrates the design configuration and first results of an eews prototype based on the u s geological survey earthworm tools and developed at the institut cartografic i geologic de catalunya icgc system main functionalities are real time data acquisition processing p wave picking event detection earthquake hypocentral location and magnitude estimation from previously calculated peak displacement p d and predominant period c of the p wave signal data archiving and earthquake early warning dissemination the prototype was put into operation after a setup period during which several simulations were carried out to establish the optimal settings after the first year of operation one felt earthquake occurred in the area of study location and magnitude results are fairly good compared with the instituto geografico nacional ign catalog lead times obtained are on the order of tens of seconds for the majority of targets which are long enough to mitigate damage for a large area of the southern coasts of portugal and spain due to the gc and sv earthquakes preliminary results for this prototype demonstrate the possibility of a regional reliable and effective eews in southwest iberia

aluminum extracts in antarctic paleosols proxy data for organic compounds and bacteria and implications for martian paleosols article i nfo pyrophosphate extractablealhasbeenusedtoestablishthepresenceoforganically complexed compoundsin middle latitude and tropical soils and paleosols on earth as proxy data used to establish the presence of organic molecules and trace movement within profiles it has proved an accurate indicator of downward translocation in spodosols podzols antarctic paleosols dating from middle to early miocene age 15 20 ma aremineralicweatheringprofileslackingaandbhorizons theseprofilesexhibitpavement cox cz cu horizons largely with sandy silt textures little clay and exceedingly low concentrations of organic matter recent chemical investigations of 33 soil samples from the new mountain and aztec mountain areas near the

earthquake early warning for southern iberia a p wave threshold based approach 1 the south of the iberian peninsula is a region in which large damaging earthquakes occur separated by long time intervals an example was the great 1755 lisbon earthquake intensity imax x which occurred sw of san vicente cape sw iberian peninsula due to this risk of damaging earthquakes the implementation of earthquake early warning system eews technologies is of considerable interest with the aim of investigating the feasibility of an eews in this region of the iberian peninsula empirical scaling relationships have been derived between the early warning parameters and the earthquake size and or its potential damaging effects for this region an appropriate and suitable strategy is proposed for an eews in the sw iberian peninsula which takes into account the limitations of the existing seismological networks

estimation of earthquake early warning parameters for eastern sicily abstract earthquake early warning systems eewss are becoming a suitable instrument for seismic risk management in real time in fact they are implemented or are undergoing testing in many countries around the world because eewss represent an effective approach to mitigating seismic risk on a short timescale eewss are based on the use of relationships between some parameters measured on the initial portion of seismic signal after the onsets here we address the first approach to the implementation of eews in eastern sicily a region that has been hit by several destructive earthquakes we estimated the peak displacement amplitude of the first portion of p and s waves p d the ground motion period parameter c and the peak ground velocity pgv from earthquakes with m l 2 8 recorded by the broadband stations operated by the istituto nazionale di geofisica e vulcanologia we found that the p d is correlated with the size of the earthquake and may be used to compute the magnitude for an eews in this area we also derived the relationships between c and m l and between p d and pgv which can be used to provide on site warning in the area around a given station and to evaluate the potential damaging effects these relationships may be deemed a useful guide for future implementation of the eews in the region

a large sedimentary basin in the terra sirenum region of the southern highlands of mars abstract different lines of evidence point to hydrological cycling in the martian past the extent duration and magnitude of this cycling remains unclear as well as the magnitude of aqueous processes on the surface here we provide geomorphic and mineralogic evidence of a large inter crater sedimentary basin located in the terra sirenum region which was once covered by a body of liquid water with an areal extent of at least 30 000 km 2 and a depth of approximately 200 m the topographic basin which is modified by a number of large impact craters is partly controlled by ancient impact and tectonic structures as a result of evaporation of the large body of water salt flats formed in the lowest topographic reaches of the basin hydrated phyllosilicates occur in close proximity to the salt flats and in the ejecta and rim materials of small impact craters with stratigraphic relations that suggest that they underlie the evaporite deposits crater statistics place the maximum age of aqueous activity during the late noachian epoch the relatively pristine mineral deposits in the basin have a high potential to yield information of the geochemistry and water activity during the ancient noachian period when conditions were seemingly more conducive to life

application of artificial neural networks as a tool for moisture prediction in microbially colonized halite in the atacama desert the atacama desert is the driest and one of the most life limiting places on earth despite the extreme conditions microbial endolithic communities have been found inside halite rocks the presence of these microbial communities is possible due to the hygroscopic properties of evaporitic rocks composed of sodium chloride it is important to elucidate every possible water source in such a hyperarid environment therefore in the present study an artificial neural network ann based model has been designed to predict the presence of liquid water on the surface of halite pinnacles the model predicts the moisture formation using two basic meteorological variables air temperature and air relative humidity anns have been successfully employed for the first time as a tool for predicting the appearance of liquid water a key factor for the endolithic microbial communities living in the driest part of the atacama desert the model developed is able to correctly predict the formation of water on the surface of the halite pinnacles 83 of the cases we anticipate the future application of this model as an important tool for the prediction of the water availability and therefore potential habitability of lithic substrates in extreme environments on earth and perhaps elsewhere

ignimbrite as a substrate for endolithic life in the hyper arid atacama desert implications for the search for life on mars the hyper arid core of the atacama desert in chile is considered the driest and most life limited place on earth with few habitats capable of sustaining an active microbial ecosystem as such it is one of the best terrestrial analogues of the extreme arid conditions on mars and an ideal environment to explore survival and biological adaptation strategies as the environment becomes increasingly dry here we show that weakly welded rhyolitic ignimbrites in this desert are abundantly colonized by endolithic cyanobacteria and associated heterotrophic bacteria we propose that the porous ignimbrite interior provides protection from damaging uv radiation and excessive levels of visible light rock porosity also favors cell hydration through water retention after scarce rainfall events even when the surrounding environment remains stubbornly dry this is the first known example of an endolithic microbial community colonizing ignimbrite rocks in an extremely dry environment the existence of a habitat capable of supporting abundant phototrophic and heterotrophic communities in an environment that precludes most life forms suggests that if similar deposits are found on mars these should be considered important targets in the search for life indeed ignimbrite rocks have been tentatively identified in gale crater the landing site of the mars science laboratory msl mission and could be directly analyzed by its rover curiosity

evaluation of meteorites as habitats for terrestrial microorganisms results from the nullarbor plain australia a mars analogue site unambiguous identification of biosignatures on mars requires access to well characterized long lasting geochemical standards at the planet s surface that can be modified by theoretical martian life ordinary chondrites which are ancient meteorites that commonly fall to the surface of mars and earth have well characterized narrow ranges in trace element and isotope geochemistry compared to martian rocks given that their mineralogy is more attractive to known chemolithotrophic life than the basaltic rocks that dominate the martian surface exogenic rocks e g chondritic meteorites may be good places to look for signs of prior life endemic to mars in this study we show that ordinary chondrites collected from the arid australian nullarbor plain are commonly colonized and inhabited by terrestrial microorganisms that are endemic to this mars analogue site these terrestrial endolithic and chasmolithic microbial contaminants are commonly found in close association with hygroscopic veins of gypsum and mg calcite which have formed within cracks penetrating deep into the meteorites terrestrial bacteria are observed within corrosion cavities where troilite fes oxidation has produced jarosite kfe so oh where terrestrial microorganisms have colonized primary silicate minerals and secondary calcite these mineral surfaces are heavily etched our results show that inhabitation of meteorites by terrestrial microorganisms in arid environments relies upon humidity and ph regulation by minerals furthermore microbial colonization affects the weathering of meteorites and production of sulfate carbonate fe oxide and smectite minerals that can preserve chemical and isotopic biosignatures for thousands to millions of years on earth meteorites are thus habitable by terrestrial microorganisms even under highly desiccating environmental conditions of relevance to mars they may therefore be useful as chemical and isotopic standards that preserve evidence of life thereby providing the possibility of universal context for recognition of microbial biosignatures on earth mars and throughout the solar system

paleostress reconstruction from kinematic indicators in the oslo graben southern norway new constraints on the mode of rifting abstract the oslo graben southern norway is a n s trending carboniferous permian rift system characterized by major mafic to silicic magmatism n s trending faults reactivation of preexisting precambrian faults and formation of half grabens magmatism is expressed by the presence of lavas dyke injections cauldron formation and the intrusion of batholiths paleostress analyses mainly based on slickensides have been performed in the area both within and outside the rift structure combined with the current tectono magmatic model of the oslo graben area the analyses show the following stress evolution from the caledonian orogeny with its compressional tectonics in the silurian to the late stages of the carboniferous permian rifting nw se compression occurred in silurian times due to the continental collision of the caledonian orogeny after a long period of a missing geological record the area was affected by n s compression during the late carboniferous a shallow sedimentary basin developed indicative for the pre and proto rift phases the transition from the proto rift phase to the initial rift phase is marked by a transition from a transpressional regime into a transtensional regime during the early permian the stress regime changed from pure extension to radial extension we suggest that the oslo graben can not simply be explained in terms of or passive or active rifting but that a combination of both evolving through time is more suitable to explain the observations we propose a model in which the oslo graben is initially triggered by far field stresses in the latest carboniferous and earliest permian which infers opening due to passive rifting these far field stresses are suggested to be linked to the hercynian orogeny active to the south in central europe in carboniferous times and the reorganisation of the pangea supercontinent in early permian times the stress regime caused radial extension indicative for uplift and a change to an active mode of rifting simultaneously with the radial extension large volumes of magma are emplaced at near surface levels despite all alternative models an anomalous thermal gradient is necessary to create these large volumes of magmatic material we propose therefore that shortly after the onset of rifting the dominant rifting mode becomes active plume related although far field stresses might still be present

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

molecular preservation in halite and perchlorate rich hypersaline subsurface deposits in the salar grande basin atacama desert chile implications for the search for molecular biomarkers on mars 1 similarities between the atacama desert chile and mars include extreme aridity highly oxidizing chemistry and intense ultraviolet radiation that promoted the photochemical production of perchlorates and nitrates concentration of these ions under hyperarid conditions led to the formation of nitrate and perchlorate bearing deposits in ephemeral lakes followed by later deposition of chlorides and sulfates at some locations such as the salar grande hypersaline deposits have remained unaltered for millions of years we conducted a drilling campaign in deposits of the salar to characterize the preservation state of biological molecules a 5 m deep discontinuous core was recovered and subjected to multitechnique analysis including the antibody microarray based biosensor ldchip300 and the solid signs of life detector instrument complemented by geophysical mineralogical geochemical and molecular analysis we identified two units based on the mineralogy the upper one from the surface to 320 cm depth characterized by a predominance of halite and anhydrite and the lower one from 320 to 520 cm with a drop in halite and anhydrite and an enrichment in nitrate and perchlorate organic compounds including biomolecules were detected in association with the different depositional and mineralogical units demonstrating the high capacity for molecular preservation hypersaline environments preserve biomolecules over geologically significant timescales therefore salt bearing materials should be high priority targets for the search for evidence of life on mars

a threshold based earthquake early warning using dense accelerometer networks most earthquake early warning systems eews developed so far are conceived as either regional network based or on site stand alone systems the recent implementation of nationwide high dynamic range dense accelerometer arrays makes now available potentially in real time unsaturated waveforms of moderate to large magnitude earthquakes recorded at very short epicentral distances 10 20 km this would allow for a drastic increase of the early warning lead time for example the time between the alert notification and the arrival time of potentially destructive waves at a given target site by analysing strong motion data from modern accelerograph networks in japan taiwan and italy we propose an integrated regional on site early warning method which can be used in the very first seconds after a moderate to large earthquake to map the most probable damaged zones the method is based on the real time measurement of the period c and peak displacement pd parameters at stations located at increasing distances from the earthquake epicentre the recorded values of early warning parameters are compared to threshold values which are set for a minimum magnitude 6 and instrumental intensity vii according to the empirical regression analyses of strong motion data at each recording site the alert level is assigned based on a decisional table with four alert levels defined upon critical values of the parameters pd and c which are set according to the error bounds estimated on the derived prediction equations given a real time evolutionary estimation of earthquake location from first p arrivals the method furnishes an estimation of the extent of potential damage zone as inferred from continuously updated averages of the period parameter and from mapping of the alert levels determined at the near source accelerometer stations the off line application of the method to strong motion records of the m w 6 3 2009 central italy earthquake shows a very consistent match between the rapidly predicted within a few seconds from the first recorded p wave and observed damage zone the latter being mapped from detailed macroseismic surveys a few days after the event the proposed approach is suitable for italy where during the last two decades a dense network of wide dynamic range accelerometer arrays has been deployed by the department of civil protection dpc the istituto nazionale di geofisica e vulcanologia ingv and other regional research agencies

fast determination of earthquake magnitude and fault extent from real time p wave recordings s u m m a r y this work is aimed at the automatic and fast characterization of the extended earthquake source through the progressive measurement of the p wave displacement amplitude along the recorded seismograms we propose a straightforward methodology to quickly characterize the earthquake magnitude and the expected length of the rupture and to provide an approximate estimate of the average stress drop to be used for earthquake earlywarning and rapid response purposes we test the methodology over a wide distance and magnitude range using a massive japan earthquake accelerogram data set our estimates of moment magnitude source duration length and stress drop are consistent with the ones obtained by using other techniques and analysing the whole seismic waveform in particular the retrieved source parameters follow a self similar constant stress drop scaling median value of stress drop 0 71 mpa for the m 9 0 2011 tohoku oki event both magnitude and length are underestimated due to limited available p wave time window ptws and to the low frequency cut off of analysed data we show that in a simulated real time mode about 1 2 seconds would be required for the source parameter determination of m 4 5 events 3 10 seconds for m 6 7 and 30 40 s for m 8 8 5 the proposed method can also provide a rapid evaluation of the average slip on the fault plane which can be used as an additional discriminant for tsunami potential associated to large magnitude earthquakes occurring offshore

self subduction of the pangaean global plate one of the most striking and rare occurrences in the earth s history is the amalgamation of most of the continental lithosphere into one supercontinent the most recent supercontinent pangaea lasted from 320 to 200 million years ago here we show that after the continental collisions that led to the formation of pangaea plate convergence continued in a large wedge shaped oceanic tract we suggest that plate strain at the periphery of the supercontinent eventually resulted in self subduction of the pangaean global plate when the ocean margin of the continent subducted beneath the continental edge at the other end of the same plate our scenario results in a stress regime within pangaea that explains the development of a large fold structure near the apex of the palaeotethys ocean extensive lower crustal heating and continental magmatism at the core of the continent as well as the development of radially arranged continental rifts in more peripheral regions of the plate

earthquake magnitude estimation from early radiated energy 1 from inspection of a large set of japanese events we investigate the scaling of the early radiated energy inferred from the squared velocity integral iv2 with the final magnitude of the event we found that the energy can only discriminate whether the event has a magnitude larger or smaller than 5 8 and in the latter case it can allow for real time magnitude estimation however by normalizing iv2 for the rupture area the initial slip scales with the magnitude between 4 m 7 following the expected scaling laws we show that the ratio between the squared peak displacement and iv2 is a proxy for the slip following the same scaling but it can be directly derived from the data without any assumption on the rupture area the scaling relationship between initial slip and magnitude can be used for early warning applications when integrated in a probabilistic evolutionary approach

surface evolution of salt encrusted playas under extreme and continued dryness miocene continental saltpans are scattered in the central valley of the atacama desert one of the driest regions on earth these evaporitic deposits are hydrologically inactive and are detached from groundwater brines or aquifers the surface of the saltpans also known as salars comprises desiccation polygons commonly with nodular salt structures along their sides the morphology and bulk mineralogy of salt polygons differs between and within salars and the shape and internal structure of salt nodules varies between different polygon types based on field observation and mineralogy and crystallography data we generated a conceptual model for the genesis and evolution of these surface features whereby rare rainfall events are responsible for the transformation of desiccation salt polygons and the initial formation of salt nodules along polygon borders in addition frequent but less intense deliquescence events further drive the evolution of salt nodules resulting in a characteristic internal structure that includes laminations and changes in porosity and crystal morphologies as a result and despite the extreme dryness the surfaces of fossil salars are dynamic on timescales of several years to decades in response to daily cycles in atmospheric moisture and also to rare and meager rainfall events we propose that fossil salars in the atacama desert represent an end stage in the evolution of evaporitic deposits under extreme and prolonged dryness

the pangea conundrum geodynamic models for supercontinent assembly whereby the dispersing continental fragments of a supercontinent break up and migrate from geoid highs to reassemble at geoid lows fail to account for the amalgamation of pangea such models would predict that the oceans created by continental breakup in the early paleozoic e g iapetus rheic would have continued to expand as the continents migrated toward sites of mantle downwelling in the paleo pacific reassembling an extroverted supercontinent as this ocean closed instead pangea assembled as a result of the closure of the younger iapetus and rheic oceans geodynamic linkages between these three oceans preserved in the rock record suggest that the reversal in continental motion may have coincided with the ordovician emergence of a super plume that produced a geoid high in the paleo pacific if so the top down geodynamics used to account for the breakup and dispersal of a supercontinent at ca 600 540 ma may have been overpowered by bottom up geodynamics during the amalgamation of pangea

rapidness and robustness of finite source inversion of the 2011 mw 9 0 tohoku earthquake by an elliptical patches method using continuous gps and acceleration data the kinematic rupture process of the 2011 mw 9 0 tohoku earthquake is inverted with an elliptical patches method using a genetic algorithm for the purpose of rapid and robust estimation of the source parameters of a mega earthquake we use the ground displacement field provided by a continuous gps network and the ground velocity field recorded by acceleration networks in addition to the typical inversion procedure in which a data duration long enough to cover the whole rupture process is used inversions based on shorter signals giving an incomplete view over the ground shaking sequence are also carried out how fast can a robust estimation of the source parameters be obtained using the elliptical approximation we find that robust solutions of mw 9 0 earthquakes are rather quickly obtained regardless of the frequency band and the elliptical patch description it is also confirmed that because of the absence of off shore recording stations on the east side of the fault some uncertainties in the rupture process cannot be completely removed in fact at the very low frequencies considered the western part of the fault deeper portion contributes more significantly to the recorded signals than does the other end close to the trench this problem also prevents refinement of the description of the rupture process in particular when using more than one ellipse

erroneous coal maturity assessment caused by low temperature oxidation previous work carried out on different outcrop coals from the french massif central revealed abnormally high tmax values which initially were attributed to high temperature oxidising fluids this increase in tmax which was exclusively observed for medium to low volatile bituminous coals rr 1 5 was accompanied by a very clear exponential like decrease of the hydrogen index hi together with an increase in the oxygen index oi with the aim of checking the possibility that this rise in tmax could simply be caused by weathering a few mature coal samples rr 1 4 were experimentally oxidised at rather low temperatures 110 125 and 150 c and for durations of up to 6 5 month then the oxidation residues were subjected to rock eval 6 pyrolysis and to vitrinite reflectance measurements these experiments effectively reproduce the geochemical changes displayed by the naturally altered coals thus supporting the hypothesis that the previously studied natural alteration process could have been ultimately caused by weathering the observed artificial oxidation path could be divided into two stages i a strong decrease in hi and an increase in oi and ii a constant hi value and a slow rise in oi the increase in tmax seems related to the transition between the first and the second stages this behaviour of hi and oi during artificial oxidation suggests that these two rock eval derived indices can be practically used to detect a moderate and even a low oxidation degree finally if one ignores the constancy of the vitrinite reflectance values all along the oxidation path the decrease of hi and the concomitant increase of tmax mimic a thermal evolution pathway

comment on chronostratigraphy and paleoclimatology of the lodeve basin france evidence for a pan tropical aridification event across the carboniferous permian boundary by michel l a tabor n j montanez i p schmitz m d davydov v i 2015 palaeogeography palaeoclimatology palaeoecology 430 118 131

a global approach to provide magnitude estimates for earthquake early warning alerts 1 we examine five different methods to estimate an earthquake s magnitude using only p wave data for use in earthquake early warning systems we test two input parameters the maximum predominant period of the p wave pmax and the displacement amplitude of the p wave s vertical component pd we apply our algorithms to 174 earthquakes 3 0 m 8 0 from california and japan that have also been used in previous calibration studies we also apply them to 1992 0 2 m 5 7 earthquakes that were processed by the real time earthquake alarm systems in california we find that pmax does not scale with magnitude for small earthquakes m 3 and is less accurate for large magnitude earthquakes than using pd alone we derive a global scaling relation between pd and magnitude and conclude that this global relationship provides the most accurate and robust magnitude estimate this relationship could be applied in earthquake source zones around the world

morphological and morphometric analysis of a topographic depression near huygens basin mars identification of a putative endorheic playa abstract inter crater depressions on mars which may be host to candidate lakes have not been explored in much detail even if a small percentage of these depressions were actually filled with water it would mean that mars was hydrologically more active than previously thought the present study examined valley networks within the equatorial region of mars analysis of the drainage networks around huygens crater revealed a topographically flat basin towards it north the basin was divided into two geological units on the basis of their morphological differences several features including wrinkled ridges dike different types of polygonal desiccation patterns pdps and craters with layered ejecta blankets were observed within the two units estimation of lobateness ejecta mobility and depth to diameter ratio of craters within these units suggest climate controlled fluctuations of volatiles and multiple episodes of resurfacing geological history of the basin was reconstituted and a possible stratigraphy was formulated after integrating basin morphology with cumulative size frequency distribution csfd analysis from the study we infer the basin to be an ephemeral endorheic playa that underwent several geodynamic processes and is a geologically rich terrain for future exploration missions

testing the earthquake early warning parameter correlations in the southern iberian peninsula the south of the iberian peninsula is of especial interest for the application of earthquake early warning system eews technologies due to the past occurrence of damaging earthquakes such as the 1755 lisbon earthquake however there are several critical issues that need to be addressed in order to develop an eews in this area the first is the magnitude scale inhomogeneity of the available catalogues a second is that most of the available broad band seismograms for this area correspond to earthquakes with magnitudes less than 6 0 recorded at distances greater than 100 km and sometimes with a low signal to noise ratio and third the occurrence of large earthquakes in this area means that the standard eews time window normally used needs to be tested in order to check whether it is long enough our paper describes the results of homogenizing the catalogue magnitudes by using empirical relationships to obtain the moment magnitude mw a criterion based on a threshold value for the signal to noise ratio is applied in order to avoid noise contaminated seismogram data an important part of the study is a check of whether the correlations previously obtained for south iberia are valid for other neighbouring areas such as algeria and for larger earthquakes finally since recent studies have shown that the larger the earthquake the longer the time window needed to properly estimate the magnitude the window was increased progressively from 0 to 20 s in order to study the behaviour of the eews parameters for the largest earthquakes in the database

sedimentology and u pb dating of carboniferous to permian continental series of the northern massif central france local palaeogeographic evolution and larger scale correlations abstract the carboniferous to permian volcanic sedimentary succession shown by the ly f core from the lucenay les aix area in the northern part of the massif central has been studied in order to obtain both landscape reconstructions sedimentological analyses and geochronological constraints u pb dating on zircon and apatite the lowermost part of the core consists mainly of lacustrine deposits with gilbert type delta and volcaniclastic rich fan delta deposits including several altered volcanic ash layers tonstein in contrast in the uppermost part of the core playa lake deposits dominate la icp ms u pb analyses were performed on both zircon and apatite grains from interbedded tonsteins this coupled u pb dating approach allows to assess potential reworking of volcanic material or the occurrence of non volcanic grains such as xenocrysts in order to provide better evaluations for the depositional ages of the tonsteins these investigations reveal that sedimentation took place between the late gzhelian and the late sakmarian i e between c 301 and 290 ma this sedimentary succession can therefore be compared to those from adjacent basins for which geochronological constraints are available i e autun and lodeve basins resp located north and south of the massif central this study provides a reference section for future comparisons with similar sections from other carboniferous to permian basins in france as well as elsewhere in europe

spectral evidence for hydrated salts in recurring slope lineae on mars transient streaks that appear seasonally on martian slopes are consistent with brine flows but evidence of water or salts has been lacking analysis of spectral data reveals hydrated salts associated with the streaks confirming a briny origin

application of real time gps to earthquake early warning in subduction and strike slip environments 1 we explore the application of gps data to earthquake early warning and investigate whether the coseismic ground deformation can be used to provide fast and reliable magnitude estimations and ground shaking predictions we use an algorithm to extract the permanent static offset fromgps displacement time series and invert for theslip distribution on the fault plane which is discretized into a small number of rectangular patches we developed a completely self adapting strategy in which the initial fault plane model is built based on a quick approximate magnitude estimation and is then allowed to increase in size based on the evolutionary magnitude estimation resulting from the slip inversion two main early warning outputs are delivered in real time magnitude and the along strike extent of the rupture area these are finally used to predict the expected ground shaking due to the finite source we tested the proposed strategy by simulating real time environments for three earthquakes for themw9 0 2011 tohoku oki earthquake our algorithm provides the first magnitude estimate of 8 2 at 39 s after the origin time and then gradually increases to 8 9 at 120 s the estimated rupture length remains constant from the outset at 360 km for the mw 8 3 2003 tokachi oki earthquake the initial magnitude estimate is 8 5 at 24 s and drops to 8 2 at 40 s with a rupture length of 290 km finally for the mw 7 2 2010 el mayor cucapah earthquake the magnitude estimate is 7 0 from the outset with a rupture length of 140 km the accuracy of the ground shaking prediction using the gps based magnitude and finite extent is significantly better than existing seismology based point source approaches this approach would also facilitate more rapid tsunami warnings

quick estimation of the magnitude and epicentral distance using the p wave for earthquakes in iran abstract a reliable estimation of the earthquake magnitude and epicentral distance within a few seconds after the p wave arrival is of great importance for earthquake early warning systems this study aims to investigate the relations between the envelope of the initial part of the p wave with epicentral distance and magnitude of the earthquakes related to the tectonic conditions of iran to this end the accelerometer waveforms of 17 earthquakes with moment magnitudes less than 7 8 and epicentral distances less than 150 km are considered a simple function with the form of y bt exp at is fitted to the initial part of the waveform envelope on time windows of 2 3 4 and 5 s by the least squares method which is constructed simply by keeping the past maximum amplitude at every moment parameters a and b are obtained to scale magnitude and epicentral distance as well the results show that log is proportional to log b in which denotes the epicentral distance the distance scaling relations for all of the time windows indicate standard deviations between 0 16 and 0 17 km for log comparing to the adopted relation in the early warning system of the japan meteorological agency results illustrate a relatively distinct slope and intercept which arises from differences in tectonic structure and features of the earthquake sources in two areas the same process for records with epicentral distances less than 50 km is also repeated results indicate smaller standard deviations between 0 13 and 0 14 km for four time windows considering the arrangement of hazardous faults in many populated districts of iran including tehran utilization of the obtained relations is recommended for distances less than 50 km moreover the current study represents two distance dependent relations between magnitudes with p max and a p max within the initial 3 s of p wave arrivals with standard deviations of 0 42 and 0 46 magnitude units respectively

final stages of the variscan orogeny at the southern iberian massif lateral extrusion and rotation of continental blocks 1 the southern part of the iberian massif contains one of the sutures of the european variscan belt several systems of faults and dikes appear as a result of a period of brittle deformation during the late stages of the variscan tectonic evolution of this zone a detailed analysis of these structures has been carried out in this work four successive deformation phases have been identified a first strike slip normal faulting stage a transcurrent stage a second strike slip normal faulting stage and finally a thrusting stage the age of these phases vary between around 310 ma and less than 270 ma the computed trajectories of the deformation axes show a progressive anticlockwise rotation of around 90 these data together with the results of previous geological and geophysical studies of this zone and of the variscan belt as a whole lead us to propose a model of tectonic evolution for the last stages of the variscan collision comparison with modern examples of collisional belts and with the results of analog experiments suggests that a promontory of the continental lithosphere of the downgoing plate indented against the active continental margin of the upper plate the indenter suffered an intense deformation in accordance with the predictions of some recent analog models simulating the indentation of a four layer continental lithosphere the variscan and late variscan brittle deformation episodes represent the waning stages of the variscan collision and not an independent tectonic event

early magnitude and potential damage zone estimates for the great mw 9 tohoku oki earthquake the mw 9 0 2011 tohoku oki earthquake has reopened the discussion among the scientific community about the effectiveness of earthquake early warning for large events a well known problem with real time procedures is the parameter saturation which may lead to magnitude underestimation for large earthquakes here we measure the initial peak ground displacement and the predominant period by progressively expanding the time window and distance range to provide consistent magnitude estimates m 8 4 and a rapid prediction of the potential damage area this information would have been available 35 s after the first p wave detection and could have been refined in the successive 20 s using data from more distant stations we show the suitability of the existing regression relationships between early warning parameters and magnitude provided that an appropriate p wave time window is used for parameter estimation we interpret the magnitude under estimation as a combined effect of high pass filtering and frequency dependence of the main radiating source during the rupture process

magnitude estimation based on integrated amplitude and frequency content of the initial p wave in earthquake early warning applied to tehran iran abstract to optimize magnitude estimation for the earthquake early warning system around the tehran region different amplitude and frequency based parameters that is predominant period characteristic period c log average period log and peak displacement p d were analyzed in this article all parameters were calculated directly from seismic records with an epicentral distance less than 150 km and within the initial 3 s of the p waves the analysis of earthquakes in the 2 4 m l p d and c were underestimated and there was no scaling relationship with the log parameter when combined with the global observations from japan taiwan and italy the results of p d and c for the tehran region produced optimized results

permian climate development in the northern peri tethys area the lodeve basin french massif central compared in a european and global context abstract the lodeve basin which contains an exceptional long and nearly uninterrupted profile of early to late permian continental red beds is well correlated to the other european permocarboniferous basins together they cover the time span from the late pennsylvanian to the permian triassic boundary although these basins were placed within the equatorial belt for the whole permian several climatic changes are recorded in the sediments terrestrial sedimentation is governed by the interaction of climate and tectonics as well as by volcanism to a variable degree therefore small scale climatic variations of the milankovitch band are hardly discernable and if so they could not be correlated between different basins indeed larger scale climatic shifts could be identified it is shown that the shift from the carboniferous icehouse to the mesozoic warmhouse was a multi stage process this global warming resulted in a general aridisation of northern pangea indicated by outspreading playa and sabkha red beds aeolianites and evaporites several short phases of increased humidity interrupted this trend indicated by wet red beds lake sediments and coal deposits in central and southern europe these wet periods are traceable within the late stephanian lower rotliegend gzhelian asselian topmost lower rotliegend asselian sakmarian upper rotliegend i late artinskian early kungurian and upper rotliegend ii zechstein wuchiapingian the aridisation of the northern pangea which accelerated near the sakmarian artinskian transition is attributed to a reorganisation of the major ocean currents cold water currents along the western flank of the pangea indicated by the permian chert event blocks moisture transport from west onto the continent during roadian and wordian the onset of an additional cold water current along the cimmerian continents blocks moisture transport from the east both phenomena together are responsible for the maximum of aridity at the early to middle permian transition additionally the equatorial climate has been affected by an increasing seasonality within the late pennsylvanian and permian caused by the wide shifting of the zone of inter tropical convergence itc over the equator based on a new reconstruction of the pangean assembly in this paper climatic changes in the permian are interpreted and causes of the arid humid arid shifts are examined phases of higher humidity are often related to events of global impact like the waxing and waning of the gondwanan glaciation obtained in the south african karoo basin dwyka group but also regional events had strong climatic influence the zechstein transgression in the northern and southern permian basin as well as the bellerophon transgression of the southern alps caused the wet phase in the wuchiapingian

facilitation of endolithic microbial survival in the hyperarid core of the atacama desert by mineral deliquescence 1 the hyperarid core of the atacama desert is considered the dry limit for life on earth soils in this region have very low abundance of heterotrophic bacteria and are practically barren of photosynthetic microorganisms because of the extreme dry conditions 2 mm a 1 rainfall however relatively abundant endolithic communities of cyanobacteria chroococcidiopsis occur within halite crusts in paleolake evaporitic deposits by means of continuous monitoring of the microclimate conditions temperature relative humidity water vapor density wetness and photosynthetically active radiation inside and around the halite crusts we demonstrate here that water vapor condenses within the pore space of the halite at relative humidity rh levels that otherwise hinder the occurrence of liquid water in the surrounding environment water condensation occurs at rh 75 which corresponds to the deliquescence point of halite we have estimated a total of 57 deliquescence events i e water condensation within the halite crusts as opposed to only 1 liquid water event outside these wet events resulted in a total of 213 8 h of potential photosynthetic activity for the endolithic microorganisms versus only 6 h for organisms outside the halite crusts halite crusts may therefore represent the last available niche for photosynthetic activity in extreme arid environments on earth

a window into the complexity of the dynamic rupture of the 2011 mw 9 tohoku oki earthquake the 2011 mw 9 tohoku oki earthquake recorded by over 1000 near field stations and multiple large aperture arrays is by far the best recorded earthquake in the history of seismology and provides unique opportunities to address fundamental issues in earthquake source dynamics here we conduct a high resolution array analysis based on recordings from the usarray and the european network the mutually consistent results from both arrays reveal rupture complexity with unprecedented resolution involving phases of diverse rupture speed and intermittent high frequency bursts within slow speed phases which suggests spatially heterogeneous material properties the earthquake initially propagates down dip with a slow initiation phase followed by sustained propagation at speeds of 3 km s the rupture then slows down to 1 5 km s for 60 seconds a rich sequence of bursts is generated along the down dip rim of this slow and roughly circular rupture front before the end of the slow phase an extremely fast rupture front detaches at about 5 km s towards the north finally a rupture front propagates towards the south running at about 2 5 km s for over 100 km key features of the rupture process are confirmed by the strong motion data recorded by k net and kik net the energetic high frequency radiation episodes within a slow rupture phase suggests a patchy image of the brittle ductile transition zone composed of discrete brittle asperities within a ductile matrix the high frequency is generated mainly at the down dip edge of the principal slip regions constrained by geodesy suggesting a variation along dip of the mechanical properties of the mega thrust fault or their spatial heterogeneity that affects rise time

evidence of large scale repeating slip during the 2011 tohoku oki earthquake 1 the repetition of slip during rupture process of earthquake is a debate issue which had never been confirmed clearly in the past big events due to the lack of dense near field observations and limited resolution in time of source model the 2011 m9 0 tohoku oki earthquake generated a wealth seismic records which provided us an unprecedented opportunity to study the rupture evolution of giant earthquake at a high spatio temporal resolution here we use teleseismic local strong motion and near field coseismic geodetic data to investigate the source rupture process of this event based on the parallel inversion technique the results reveal a broad slip zone with remarkable large scale repeating slip during the earthquake the inverted source model shows several time periods of energy release with three main peaks these energy bursts and temporal rupture snapshots suggest repetition of a large scale slip on the biggest asperity this rupture behavior resulted in 50 m slips on the slip zone and prolonged the entire rupture process for a long duration of 160 seconds the proposed source model is in a good agreement with the aftershock distribution and can interpret the characteristics of local strong motions further investigations of repeating slip during this event are crucial which will deeply transform earthquake science from dynamic point of view

rates and geochemical processes of soil and salt crust formation in salars of the atacama desert chile abstract the hyperarid atacama desert contains numerous local basins with surficial salt crusts known as salars where evaporation of shallow groundwater drives the major soil processes we examine chemical and isotopic profiles in two soils of differing ages from the salar llamara to determine the geochemical processes involved in their formation evaporation which provides salts to the soils through mineral precipitation decreases with increasing salt crust thickness and average 0 03 mm m 2 d 1 over geological time frames salt distribution varies predictably with depth and soil age with the most soluble compounds concentrated nearest to the land surface indicating the direction of fluid flow 34s values of mineral sulfate tend to decrease with decreasing soil depth following a pattern indicative of rayleigh like fractionation as solute rich waters migrate toward the land surface 13c and 18o values of carbonate suggest that the uppermost halite layers which contain very small amounts of carbonate have a strong biological signature in contrast carbonate rich layers deeper in the profiles consist of largely unmodified lacustrine carbonate that formed in highly evaporitic lake conditions the continuous upward evaporation of water and dissolved solutes creates a rugged and physically dynamic halite crust composed of rounded salt nodules the crust undergoes deliquescence as atmospheric relative humidity rises from marine air intrusions and we found that the halite nodules on the surface of the salar llamara are nearly always at or above deliquescence relative humidity the interiors of these nodules are therefore able to buffer the large diurnal changes in atmospheric relative humidity allowing for the survival of halophilic microbial communities in an otherwise very dry environment radiocarbon measurements of occluded organic c in the surface crusts indicate that c cycling occurs at differing rates depending on local micrometeorological conditions and that a given salt crust feature may persist for thousands of years once formed

stability of liquid saline water on present day mars 1 perchlorate salts mostly magnesium and sodium perchlorate have been detected on mars arctic soil by the phoenix lander furthermore chloride salts have been found on the meridiani and gusev sites and on widespread deposits on the southern martian hemisphere the presence of these salts on the surface is not only relevant because of their ability to lower the freezing point of water but also because they can absorb water vapor and form a liquid solution deliquesce we show experimentally that small amounts of sodium perchlorate 1 mg at mars atmospheric conditions spontaneously absorb moisture and melt into a liquid solution growing into 1 mm liquid spheroids at temperatures as low as 225 k also mixtures of water ice and sodium perchlorate melt into a liquid at this temperature our results indicate that salty environments make liquid water to be locally and sporadically stable on present day mars

test of a threshold based earthquake early warning method using japanese data most of existing earthquake early warning systems are regional or on site systems a new concept is the integration of these approaches for the definition of alert levels and the estimation of the earthquake potential damage zone pdz the key element of the method is the real time simultaneous measurement of initial peak displacement p d and period parameter c in a 3 s window after the first p wave arrival time at accelerometer stations located at increasing distances from the epicenter as for the on site approach the recorded values of p d and c are compared to threshold values which are set for a minimum magnitude m 6 and instrumental intensity i mm vii according to empirical regression analysis of strong motion data from different seismic regions at each recording site the alert level is assigned based on a decisional table with four entries defined by threshold values of the parameters p d and c a regional network of stations provides the event location and transmits the information about the alert levels recorded at near source stations to more distant sites before the arrival of the most destructive phase we present the results of performance tests of this method using ten m 6 japanese earthquakes that occurred in the period 2000 2009 and propose a very robust methodology for mapping the pdz in the first seconds after a moderate to large earthquake the studied cases displayed a very good matching between the rapidly predicted earthquake pdz inferred from initial p peak displacement amplitudes and the instrumental intensity map the latter being mapped after the event using peak ground velocity and or acceleration or from field macroseismic surveys

late orogenic carboniferous extensions in the variscan french massif central the variscan french massif central experienced two successive stages of extension from middle carboniferous to early permian in the northern massif central the first stage began in the late visean immediately after nappe stacking and is well recorded by namurian westphalian synkinematic plutonism the middle carboniferous leucogranites widespread in the nw massif central limousin and sioule area were emplaced within a crust extending along a ne sw direction at the same time the hanging wall or gueret extensional allochton moved toward the se several examples of the synextensional plutonism are also recognized in central limousin saint mathieu dome la porcherie and cornil leucogranites these examples illustrate the relationship between granite emplacement and crustal scale deformation characterized by nw se stretching and ne sw shortening in the central and southern massif central cevennes ch taigneraie and margeride areas plutonism is dominantly granodioritic and exhibits the same structural features nw se maximum stretching and overturning to the se middle carboniferous namurian westphalian extension was parallel to the variscan belt both in the massif central and southern armorican area this extensional regime was active from the late visean in the north while compression dominated in the southernmost domains montagne noire and pyrenees the second extensional stage occurred from late carboniferous to early permian this event was responsible for the opening of intramontane coal basins brittle deformation in the upper crust and ductile normal faulting localized on the margin of cordierite granite migmatite domes data from the coal basins show that the half graben is the dominant structural style except for basins located along submeridianal left lateral faults which have pull apart geometries late carboniferous extension occurred along the ne sw direction the ne sw maximum stretching direction can be found in the whole massif central but is more developed in the eastern part the extensional direction is transverse to the general trend of the belt and top to the ne shearing is dominant correlations of these two extension directions with neighboring variscan massifs are discussed

paleosols in clastic sedimentary rocks their geologic applications interest in pre quaternary paleosols has increased over the past decade in large part because they have proved to be beneficial in solving diverse geological problems the majority of paleosols are described from continental deposits most commonly from alluvial strata criteria for recognizing these paleosols have been extensively described however classifying them has proved more complicated pre quaternary paleosols are generally classified according to one or more modern soil classification systems although one new classification has been proposed exclusively for paleosols to avoid problems using the modern soil classifications in addition to taxonomic classification paleosols can be categorized according to the interplay among deposition erosion and the rate of pedogenesis when they formed paleosols can be solitary if they formed during a period of landscape stability following the development of an unconformity such paleosols are commonly thick and extremely well developed more commonly paleosols are vertically stacked or multistory because they formed in sedimentary systems undergoing net aggradation if erosion was insignificant and sedimentation was rapid and unsteady compound paleosols generally formed if the rate of pedogenesis exceeded the rate of deposition composite paleosols developed thick cumulative paleosols indicate that erosion was insignificant and that sedimentation was relatively steady both autogenic and allogenic processes can influence depositional and erosion patterns and thus affect the kinds of soils that form consequently paleosols can help to interpret the history of sediment deposition and the autogenic and allogenic processes that influenced a sedimentary basin paleosols are also helpful in stratigraphic studies including sequence stratigraphic analyses they are used for stratigraphic correlations at the local and basinal scale and some workers have calculated sediment accumulation rates based on the degree of paleosol development in addition to their stratigraphic applications paleosols can be used to interpret landscapes of the past by analyzing paleosol landscape associations at different spatial scales ranging from local to basin wide in scope at the local scale lateral changes in paleosol properties are largely the result of variations in grain size and topography at the scale of the sedimentary basin paleosols in different locations differ because of basinal variations in topography grain size climate and subsidence rate paleosols are used to reconstruct ancient climates even to estimate ancient mean annual precipitation map and mean annual temperature mat ancient climatic conditions can be interpreted from modern soil analogs or by identifying particular pedogenic properties that modern studies show to have climatic significance stable carbon and oxygen isotopes are also used to interpret ancient climate and some effort has been made to estimate mat from isotopic composition on the basis of

neogene evaporites in desert volcanic environments atacama desert northern chile the upper miocene and pliocene evaporite deposits of the atacama desert of northern chile hilaricos and soledad formations are among the few nonmarine evaporites in which aridity not only formed the deposits but has also preserved them almost unaltered under near surface conditions these deposits are largely composed of displacive ca sulphate and halite together with minor amounts of glauberite thenardite and polyhalite however at the base and top of these deposits there are also beds of gypsum crystal pseudomorphs that originally formed as free growth forms within shallow brine bodies rather than as displacive sediments the halite is present as interstitial cement displacive cubes and shallow water bottom growth chevron crusts most of the calcium sulphate is presently anhydrite pseudomorphous after gypsum that was the primary depositional sulphate mineral the secondary anhydrite formed under early diagenetic conditions after slight burial some metres resulting from the effect of strongly evolved pore brines the anhydrite has been preserved without rehydration during late diagenetic and exhumation stages on account of the arid environment of the atacama desert both the hilaricos and the soledad formations contain geochemical markers indicating that these neogene evaporites had a largely non marine origin bromine content in the halite is very low few p p m indicating neither a sedimentological relation with sea water nor the likelihood of direct recycling of prior marine halites moreover the d 34 s of sulphates 4ae5 to 9 also reflects a non marine origin with a strong volcanic influence although some recycling of mesozoic marine sulphates cannot be ruled out d 34 s of dissolved sulphate from hot springs and streams in the area commonly displays positive values 2 to 10 leaching of oxidized sulphur and chlorine compounds from volcanoes and epithermal ore bodies very common in the associated drainage areas have been the main contribution to the accumulation of evaporites the sedimentary and diagenetic evolution of the hilaricos and soledad evaporites based on lithofacies analysis provides information about the palaeohydrological conditions in the central depression of northern chile during the neogene in addition the diagenesis and exhumation history of these evaporites confirms the persistence of strongly arid conditions from late miocene until the present a final phase of tectonism took place permitting the internal drainage to change and open to the sea resulting in dissolution and removal of a significant portion of these deposits despite the extensive dissolution the remaining evaporites have undergone little late exhumational hydration

the stable isotope composition of halite and sulfate of hyperarid soils and its relation to aqueous transport halite nacl and gypsum or anhydrite caso4 are water soluble minerals found in soils of the driest regions of earth and only modest attention has been given to the hydrological processes that distribute these salts vertically in soil profiles the two most notable chloride and sulfate rich deserts on earth are the dry valleys of antarctica and the atacama desert of chile while each is hyperarid they possess very different hydrological regimes we first show using previously published s and o isotope data for sulfate minerals that downward migration of water and sulfate is the primary mechanism responsible for depth profiles of sulfate concentration and s and o isotopes in both deserts in contrast we found quite different soluble cl concentration and cl isotope profiles between the two deserts for antarctic soils with an ice layer near the soil surface the cl concentrations increase with decreasing soil depth whereas the ratio of 37 cl 35 cl increases based on previous field observations by others we found that thermally driven upward movement of brine during the winter described by an advection diffusion model qualitatively mimics the observed profiles in contrast in the atacama desert where rare but relatively large rains drive cl downward through the profiles cl concentrations and 37 cl 35 cl ratios increased with depth the depth trends in cl isotopes are more closely explained by a rayleigh like model of downward fluid flow the isotope profiles and our modeling reveal the similarities and differences between these two very arid regions on earth and are relevant for constraining models of fluid flow in arid zone soil and vadose zone hydrology 2012 elsevier ltd all rights reserved

in situ evidence for an ancient aqueous environment at meridiani planum mars sedimentary rocks at eagle crater in meridiani planum are composed of fine grained siliciclastic materials derived from weathering of basaltic rocks sulfate minerals including magnesium sulfate and jarosite that constitute several tens of percent of the rock by weight and hematite cross stratification observed in rock outcrops indicates eolian and aqueous transport diagenetic features include hematite rich concretions and crystal mold vugs we interpret the rocks to be a mixture of chemical and siliciclastic sediments with a complex diagenetic history the environmental conditions that they record include episodic inundation by shallow surface water evaporation and desiccation the geologic record at meridiani planum suggests that conditions were suitable for biological activity for a period of time in martian history

earthquake magnitude estimation from peak amplitudes of very early seismic signals on strong motion records 1 we show that the low pass filtered peak amplitudes of initial p and s wave seismic signals recorded in the vicinity of an occurring earthquake source correlates with the earthquake magnitude and may be used for real time estimation of the event size in seismic early warning applications the earthquake size can be therefore estimated using only a couple of seconds of signal from the p or s wave onsets i e while the rupture itself is still propagating and rupture dimension is far from complete we argue that dynamic stress release and or slip duration on the fault in the very early stage of seismic fracture scales both with the observed peak amplitude and with the elastic energy available for fracture propagation the probability that a fracture grows to a larger size should scale with the energy initially available citation zollo a m lancieri and s nielsen 2006 earthquake magnitude estimation from peak amplitudes of very early seismic signals on strong motion records geophys res lett 33 l23312 doi 10 1029 2006gl027795