quasi real time fault model estimation for near field tsunami forecasting based on rtk gps analysis application to the 2011 tohoku oki earthquake mw 9 0 1 real time crustal deformation monitoring is extremely important for achieving rapid understanding of actual earthquake scales because the measured permanent displacement directly gives the true earthquake size seismic moment mw information which in turn provides tsunami forecasting we have developed an algorithm to detect estimate static ground displacements due to earthquake faulting from real time kinematic gps rtk gps time series the new algorithm identifies permanent displacements by monitoring the difference of a short term average sta to a long term average lta of the gps time series we assessed the noise property and precision of the rtk gps time series with various baseline length conditions and orbits and discerned that the real time ephemerides based on the international gnss service igs are sufficient for crustal deformation monitoring with long baselines up to 1 000 km we applied the algorithm to data obtained in the 2011 off the pacific coast of tohoku earthquake mw 9 0 to test the possibility of coseismic displacement detections and further we inverted the obtained displacement fields for a fault model the inversion estimated a fault model with mw 8 7 which is close to the actual mw of 9 0 within five minutes from the origin time once the fault model is estimated tsunami waveforms can be immediately synthesized using pre computed tsunami green s functions the calculated waveforms showed good agreement with the actual tsunami observations both in arrival times and wave heights suggesting that the rtk gps data by our algorithm can provide reliable rapid tsunami forecasting that can complement existing tsunami forecasting systems based on seismic observations

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

variation of lithium isotope composition in the marine environment a preliminary report the li isotopic compositions of ocean waters lake water hydrothermal solutions altered and unaltered basalts have been determined using the technique of thermal ionization mass spectrometry of lithium tetraborate seawater appears to be homogeneous in li isotopic composition the mean delta sup 6 li value is minus 32 3 plus minus 0 5 per thousand relative to an isotopic standard three lakes studied lake tanganyika caspian sea and dead sea yield delta sup 6 li similar to the seawater isotopic composition a fresh basalt glass from 21 degree n east pacific rise displays a delta sup 6 li value of minus 4 7 per thousand a hydrothermal solution from a 21 degree n vent field has delta sup 6 li of minus 10 per thousand indicating incomplete extraction of li from the igneous minerals or partial retention in secondary phases the alteration margin of a basalt from the mid atlantic ridge has delta sup 6 li of minus 8 4 per thousand the isotope data of submarine basalts suggest preferential removal of sup 6 li from seawater into alteration minerals during low temperature weathering the delta sup 6 li values of two hydrothermal solutions from guaymas basin were found to be minus 5 per thousand and minus 10 per thousand the results can be interpreted as the net effect of li addition from basalt and sediments and incorporation in hydrothermal precipitates as the hydrothermalmore fluids interact with basin sediments the observed enrichment of sup 7 li in seawater relative to submarine hydrothermal solutions its principal li input is tentatively attributed to isotopic fractionation associated with low temperature alteration of sea floor basalt and incorporation in authigenic sediments it appears that the li isotope system may have characteristics that can resolve the mass balance of li in the ocean less

li ca in multiple species of benthic and planktonic foraminifera thermocline latitudinal and glacial interglacial variation li ca ratios were measured in planktonic and benthic foraminifera from a variety of hydrographic settings to investigate the factors influencing lithium incorporation into foraminiferal tests including temperature dissolution pressure and interspecies differences down core measurements of planktonic orbulina universa globigerinoides ruber and globigerinoides sacculifer and benthic foraminifera calcitic cibicides wuellerstorfi and aragonitic hoeglandina elegans show a systematic variation in li ca with 18o through the last glacial interglacial transition all species examined exhibit an increase in li ca between 14 to 50 from the holocene to the last glacial maximum li ca generally increases with decreasing temperature as seen in a latitudinal transect of planktonic o universa and down slope benthic species along the bahama bank margins postdepositional dissolution possibly causes a decrease in planktonic foraminiferal li ca along the sierra leone rise and increased water depth causes a decrease in benthic foraminiferal li ca in the deep caribbean however none of these effects are sufficient to account for the observed glacial interglacial changes physiological factors such as calcification rate may affect the li ca content of foraminiferal calcite the calcification rate in turn may be a function of carbonate ion concentration of ambient ocean water this work shows that incorporation of lithium by foraminifera appears to be influenced by factors other than seawater composition and does not appear to be dominated by changes in temperature dissolution or pressure we hypothesize that the consistent increase in foraminiferal li ca during the last glacial maximum may be linked to changes in seawater carbonate ion concentration important parameters to be tested include calcification rate and foraminiferal test size and weight if foraminiferal li ca is dominantly controlled by calcification rate as a function of seawater carbonate ion concentration then li ca may act as a proxy of past atmospheric co2

effect of mineralogy salinity and temperature on li ca and li isotope composition of calcium carbonate li ca and li isotope ratios in marine and freshwater calcium carbonates are potential tracers of past environmental variables such as weathering intensity and temperature to make use of their potential requires full understanding of the fractionation of li ca and 7 li 6 li during growth of calcium carbonate this study improves such understanding with two sets of new measurements on inorganic calcites and aragonites precipitated over a range of salinity and on the test of benthic foraminifera formed at a range of temperatures li ca in inorganic calcite increases by a factor of four as salinity increases from 10x to 50x inorganic aragonite demonstrates no significant change in li ca over the same salinity range the difference in behaviour is probably due to the incorporation mechanism of li substitution of li in the ca 2 site in aragonite makes growth solution li ca the key variable while interstitial incorporation of li in calcite means that the growth solution li concentration is more important compared to the growth solution 7 li 6 li is c3x lower in calcite and c11x lower in aragonite with no relationship to salinity for either mineral similar isotope fractionation to these inorganic experiments are observed for biogenically produced calcite foraminifera and aragonite corals this suggests little biological control during li incorporation into biogenic calcium carbonates the difference in fractionation between calcite and aragonite is consistent with an equilibrium isotope fractionation reflecting different incorporation mechanisms for li into the two minerals four samples of the benthic foraminifera uvigerina precipitated over a temperature range of 14 8c have li ca ranging from 18 5 to 13 1 amol mol the ratio is inversely related to temperature with a sensitivity of 2 5f0 8 per 8c this sensitivity is similar to that observed in a previous study of foraminiferal li ca but about half that observed during inorganic calcite growth the large variability in both li ca and temperature sensitivity exhibited between various foraminifera species suggests an additional control on calcite li ca apart from those of salinity and temperature observed in this study d 2004 elsevier b v all rights reserved

operational real time gps enhanced earthquake early warning moment magnitudes for large earthquakes mw 7 0 derived in real time from near field seismic data can be underestimated due to instrument limitations ground tilting and saturation of frequency amplitude magnitude relationships real time high rate gps resolves the buildup of static surface displacements with the s wave arrival assuming nonsupershear rupture thus enabling the estimation of slip on a finite fault and the event s geodetic moment recently a range of high rate gps strategies have been demonstrated on off line data here we present the first operational system for real time gps enhanced earthquake early warning as implemented at the berkeley seismological laboratory bsl and currently analyzing real time data for northern california the bsl generates real time position estimates operationally using data from 62 gps stations in northern california a fully triangulated network defines 170 station pairs processed with the software trackrt the bsl uses g larms the geodetic alarm system to analyze these positioning time series and determine static offsets and preevent quality parameters g larms derives and broadcasts finite fault and magnitude information through least squares inversion of the static offsets for slip based on a priori fault orientation and location information this system tightly integrates seismic alarm systems cisn shakealert elarms 2 as it uses their p wave detections to trigger its processing quality control runs continuously we use a synthetic hayward fault earthquake scenario on real time streams to demonstrate recovery of slip and magnitude reanalysis of the mw7 2 el mayor cucapah earthquake tests the impact of dynamic motions on offset estimation using these test cases we explore sensitivities to disturbances of a priori constraints origin time location and fault strike dip

textural elemental and isotopic variations among constituents in middle devonian limestones north america abstract biogenic components brachiopods crinoids and corals in middle devonian limestones were manually separated from their enclosing matrix and analyzed by textural elemental and isotopic methods in order to assess the preservational state of these components in general brachiopods in these rocks are better preserved texturally than other constituents as determined by sem and cathodoluminescence observations elemental variations among the major components are compatible with a differential response to diagenesis governed by the relative stability of the original mineralogy of the component however among the most stable low mg calcite brachiopods the relationship between textural preservation and trace element content is complex this apparent complexity may be due at least par ially to our method of textural characterization of whole brachipod samples the nonluminescent portions of a set of well preserved brachipods have textural characteristics and elemental contents which are virtually indistinguishable from modern representatives consequently their 18o values 3 7 0 2 are assumed to represent primary biogenic calcite these 18o values are in the heavy end of the range of values from texturally well preserved whole brachiopods 6 6 to 2 5 texturally altered whole brachiopods 6 7 to 3 7 and texturally altered crinoids and cora s 6 7 to 2 7 this comparison suggests that marine derived pore waters were a predominant component during the principal phase of diagenesis the relatively low l8o values of well preserved brachiopods compared with modern representatives implies that middle devonian seawater was either warmer by about 10 c or depleted in 18o by about 2 3 relative to modern seawater

lithium in foraminiferal shells implications for high temperature hydrothermal circulation fluxes and oceanic crustal generation rates the lithium content of planktonic foraminiferal calcite has been determined to evaluate temporal variability of seawater li concentrations over the past 116 m y mean foraminiferal calcite lithium calcium in each time interval is no more than 16 greater nor 25 less than the mean li ca of all samples li ca minima are observed for samples from 50 60 m y and 80 90 m y with li ca about 25 lower than in adjacent time intervals at no time during the past 40 m y does mean li ca appear to be higher than that at present subject to the limitations imposed by sample coverage and diagenesis a similar conclusion holds for the past 116 m y coupled with an oceanic mass balance model for li these data suggest that 1 oceanic li concentrations and therefore high temperature hydrothermal circulation fluxes during the past 40 m y and perhaps the past 100 m y have not been more than perhaps 30 40 greater than at present for intervals any longer than a million years at most and 2 these fluxes werenot a factor of two higher 100 m y ago by inference variations in oceanic crustal generation rates over these time periods are similarly limited decreases in hydrothermal circulation fluxes and crustal generation rates or fluctuations up to 20 in these rates of a few million years duration arenot necessarily ruled out by the li ca data the lack of variability in li ca over time is not unequivocal evidence that hydrothermal fluxes have not varied because the rates of removal processes may be linked to changes in input fluxes

derivation of the original isotopic composition of permian marine cements abstract diagenesis of former aragonite and magnesian calcite marine cements of the permian reef complex has resulted in a fine scale intermixture of two distinct secondary phases a luminescent and a nonluminescent calcite multiple carbon and oxygen isotopic analyses of these marine cements from any single sample result in a linear covariant trend reflecting random proportions of the two calcite phases contained in individual analyses the convergence of four trends derived from samples of former aragonite marine cement collected at four sites along a single upper capitan paleoslope fixes the isotopic composition of the nonluminescent calcite at a value of 2 518o 5 313c likewise covariant trends from former aragonite cements in the lower capitan and the youngest upper capitan yield nonluminescent calcite compositions of 2 818o 5 213c and 0 718o 5 813c respective y the single covariant trend generated from former magnesian calcite cements does not converge with equivalent former aragonite covariant trends indicating that the precursor mineralogy influences the isotopic composition of the nonluminescent calcite considered as a whole the invariance of the nonluminescent calcite signature the timing of luminescent calcite emplacement and the fine scale of the fabric retention suggest that the precipitation of the nonluminescent calcite occurred while isolated from effective isotopic exchange with external diagenetic fluids a direct consequence of this low water rock ratio closed system is that the isotopic signature of the nonluminescent calcite also represents the original isotopic composition of the marine cement this is further support d by the preservation of primary differences between the original isotopic compositions of aragonite and magnesian calcite cements the constancy of the marine isotopic signature throughout the reef massive and foreslope facies requires that the delaware basin water mass was relatively well mixed comparison of marine compositions throughout the range of the capitan samples indicates that although the oxygen composition of the marine cements was apparently constant through much of the guadalupian a substantial enrichment in 18o occurred at the very end of the guadalupian this relatively abrupt change recording a concomitant change in the oxygen composition of the delaware basin water mass was probably the result of increased restriction of the delaware basin and marked the first step in the sequence of events which led to the deposition of the deep basin evaporites of the castile formation

sequential h κ stacking to obtain accurate crustal thicknesses beneath sedimentary basins abstract low velocity sedimentary basins introduce error in many standard receiver function rf analysis techniques including common conversion point dueker and sheehan 1997 and crustal thickness v p v s ratio h stacking zhu and kanamori 2000 we describe a simple rf analysis method for obtaining accurate crustal thickness below seismic stations located in sedimentary basins the method extends the methods of zhu and kanamori 2000 it employs an iterative two layer depth v p v s stacking approach that first characterizes sediment properties thickness and v p v s allowing for the accurate interpretation of moho conversions without accounting for sedimentary layers standard rf analysis can mischaracterize crustal thickness based on ps phase delay by 10 km beneath deep basins we test the technique with synthetic seismograms and with data from us array transportable array ta stations from regions with sediment thicknesses that are well determined through other means we find sequential h stacking for sediment properties to be a simple technique that can benefit many rf analysis studies and can play an important role in crustal seismic studies in areas with thick or variable sediments

comparison of atlantic and pacific paleochemical records for the last 215 000 years changes in deep ocean circulation and chemical inventories abstract detailed cd ca and 13 c data have been obtained for benthic foraminifera from western north atlantic and equatorial pacific sediment cores in the modern ocean both tracers are closely linked to nutrient distributions the sedimentary records for both tracers indicate that bottom waters overlying the atlantic site have been nutrient depleted relative to those at the pacific site over the last 215 000 years from this evidence it is reasonable to infer that there has been a continuous net flux of nutrient depleted water from the western north atlantic into the pacific this exchange has undergone significant fluctuations with the export of nutrient depleted atlantic water diminishing by about a factor of two relative to the inflow from southern ocean sources over the last 215 000 years carbon isotope fluctuations in both regions are dominated by variable storage of isotopically light carbon on continents with a lesser contribution from these deep ocean circulation changes the cadmium signal in the north atlantic is dominated by changes in deep ocean circulation patterns cadmium shows less variability in the pacific which may reflect changes in the global average cadmium content or minor changes in deep pacific circulation patterns using these records to estimate global averages it appears that glacial ocean water had 22 more cd and 0 46 less 13 c than the modern ocean these numbers are estimates which may be revised as more data become available although they are not likely to be as much as 20 in error for cd or 0 2 for 13 c relative north atlantic deep water nadw formation rates are modulated with a significant 41 kyr periodicity linked to obliquity induced variations in high latitude insolation nadw lags 8 2 kyr behind insolation however

stable carbon and oxygen isotope shifts in permian seas of west spitsbergen global change or diagenetic artifact we performed petrographic cathodoluminescence electron microprobe and isotopic analyses of brachiopod shells from the permian kapp starostin formation in west spitsbergen to reevaluate the 9 negative shift in 13c and 18o values reported in 1989 by m gruszczynski s halas a hoffman and k malkowski the 13c and 18o values within shells typically decrease with increasing luminescence indicating diagenesis nonluminescent nl shell 13c and 18o values are 4 3 and 6 2 higher respectively than those of associated cements and matrix for the same stratigraphic interval 13c and 18o values of the nl shells are equal to or substantially greater than those reported by gruszczynski et al for the interval where those authors saw a 10 13c shift our mostly nl spiriferella polaris shells only yield a 1 5 shift gruszczynski et al reported a 9 18o shift whereas we observe almost none our results strongly suggest that the 9 isotopic shifts reported in gruszczynski et al are diagenetic artifacts on the other hand their kazanian tatarian 13c maximum of 7 5 is substantiated by our data this late permian 13c maximum represents the highest spiriferid brachiopod 13c values in the phanerozoic and within stratigraphic uncertainty correlates with the whole rock 13c maximum in east greenland and northwestern europe the 13c shift may reflect changes in global storage of organic carbon indicated by coal volume changes in the late permian

stability of rapid finite fault inversion for the 2014 mw6 1 south napa earthquake local seismograms are useful for rapidly reconstructing kinematic finite fault sources but the results often depend not only on the data coverage but also on uncertainties of parameters e g hypocentral location and fault geometry used as a priori information during the inversion an automatic scheme was applied to offline tests for the 2014 south napa earthquake in the case of retrospective full waveform inversions a network with station spacing of 10 km within the epicentral distance of 30 km is able to provide adequate stable key source parameters if the preestimated hypocenter and fault orientation are accurate of 5 km and 15 respectively in simulated real time inversions the magnitude reaches mw6 0 at 13 s and the slip distribution matches that from the retrospective inversion at about 22 28 s after the origin time of the earthquake these results are meaningful for estimating the lead time of a catastrophic seismic event

assessing the biomineralization processes in the shell layers of modern brachiopods from oxygen isotopic composition and elemental ratios implications for their use as paleoenvironmental proxies abstract fossil brachiopod shells are often used as valuable archives to reconstruct paleoenvironmental conditions in deep time however biomineralization processes can impact their fidelity as geochemical proxies brachiopod shells comprise an outer primary layer a secondary fibrous layer and sometimes a tertiary columnar layer therefore it is essential to assess the potential effects of the biomineralization processes in each of the different shell microstructures of modern brachiopods this study analyses the oxygen isotopic composition together with li ca na ca mg ca and sr ca data at high spatial 20 50 m resolution in seven modern brachiopod species focusing on differences between the primary secondary and tertiary layers in all studied species 18o values of the outer primary layer are consistently out of equilibrium with seawater also this shell layer is enriched in li na mg and sr contrary to the primary layer the innermost secondary layer is near or at oxygen isotopic and elemental equilibrium with ambient seawater the columnar tertiary shell layer if present has the least variable and the heaviest oxygen isotopic composition within the range of equilibrium values with seawater this tertiary layer however is depleted in minor and trace elements relative to the other shell layers thus the tertiary layer is more suitable for oxygen isotopic studies whereas the innermost secondary layer of the most mature parts of the shell is the best target in two layered shells while we do not observe any clear interspecific relationships between mg ca and sr ca ratios on one hand and environmental parameters such as temperature salinity and ph on the other hand there is a positive interspecific relationship between na ca and salinity and a negative interspecific relationship between li ca and temperature suggesting their potential use as proxies of physicochemical parameters of seawater

sr mg ratios of modern marine calcite empirical indicators of ocean chemistry and precipitation rate holocene biotic and abiotic marine calcite have a similar range of mg contents 0 to 22 and 4 to 21 mol mgco3 respectively yet biotic calcite has sr2 concentrations that are consistently 1250 ppm higher than those of abiotic calcite as in laboratory experiments a positive linear relation is observed between dsr and calcite mg content this produces two distinct linear trends on a plot of sr2 vs mg2 concentrations principal axes of variation for both trends have similar slopes yet distinctly different sr2 concentration intercepts biotic y 0 024x 1298 r2 0 70 abiotic y 0 027x 47 r2 0 77 the similar slopes of these trends reflect the constancy of mgca and srca ratios of modern seawater equations describing the dependence of dsr on calcite mg content are derived from both trends biotic dsr 3 16 x 10t 6 ppm mg 0 169 abiotic dsr 3 52 x 10 6 ppm mg 0 0062 characterization of sr mg trends for holocene materials allows comparison with analogous trends from ancient samples to estimate relative changes in seawater mgca and srca ratios the relatively high sr contents of biotic calcite result from rapid precipitation rates associated with shell accretion in marine organisms calcites precipitated from seawater in laboratory experiments have dsr values that are similar to those of biotic marine calcite suggesting that both precipitate at approximately the same rate our estimates of surface area normalized precipitation rates in planktonic and benthonic foraminifera are comparable to those of seeded ph stat experiments we conclude that the dsr values for biotic and experimental marine calcite are kinetically controlled whereas the lower precipitation rates of abiotic marine calcite yield dsr values that approximate equilibrium conditions experimentally derived equations describing the relation between dsr and calcite precipitation rate indicate that the offset in sr content between biotic and abiotic calcite is the result of abiotic precipitation rates that are two to five orders of magnitude lower than those of biotic precipitates however observations of naturally occurring marine cements suggest that the five order of magnitude offset best represents natural system processes

seismogeodesy of the 2014 mw6 1 napa earthquake california rapid response and modeling of fast rupture on a dipping strike slip fault real time high rate geodetic data have been shown to be useful for rapid earthquake response systems during medium to large events the 2014 mw6 1 napa california earthquake is important because it provides an opportunity to study an event at the lower threshold of what can be detected with gps we show the results of gps only earthquake source products such as peak ground displacement magnitude scaling centroid moment tensor cmt solution and static slip inversion we also highlight the retrospective real time combination of gps and strong motion data to produce seismogeodetic waveforms that have higher precision and longer period information than gps only or seismic only measurements of ground motion we show their utility for rapid kinematic slip inversion and conclude that it would have been possible with current real time infrastructure to determine the basic features of the earthquake source we supplement the analysis with strong motion data collected close to the source to obtain an improved postevent image of the source process the model reveals unilateral fast propagation of slip to the north of the hypocenter with a delayed onset of shallow slip the source model suggests that the multiple strands of observed surface rupture are controlled by the shallow soft sediments of napa valley and do not necessarily represent the intersection of the main faulting surface and the free surface we conclude that the main dislocation plane is westward dipping and should intersect the surface to the east either where the easternmost strand of surface rupture is observed or at the location where the west napa fault has been mapped in the past

automatic earthquake confirmation for early warning system earthquake early warning studies are shifting real time seismology in earthquake science they provide methods to rapidly assess earthquakes to predict damaging ground shaking preventing false alarms from these systems is key here we developed a simple robust algorithm authorizing ground shaking for earthquake early warning systems agrees to reduce falsely issued alarms this is a network threshold based algorithm which differs from existing approaches based on apparent velocity of p and s waves agrees is designed to function as an external module to support existing earthquake early warning systems eewss and filters out the false events by evaluating actual shaking near the epicenter our retrospective analyses of the 2009 l aquila and 2012 emilia earthquakes show that agrees could help an eews by confirming the epicentral intensity furthermore agrees is able to effectively identify three false events due to a storm a teleseismic earthquake and broken sensors in irpinia seismic network italy

87sr 86sr ratios in permo carboniferous sea water from the analyses of well preserved brachiopod shells abstract sr isotopic analyses of well preserved portions of permo carboniferous brachiopods distributed globally confirm the general shape of the sr isotope age curve established by previous workers for this time interval there is little variation between the sr isotopic composition of unaltered portions of brachiopods and that of portions of the same shell interpreted to be diagenetically altered based on cathodoluminescence elemental and stable isotopic data however the sr isotopic composition in diagenetically altered micritic matrix adjacent to the shell is more radiogenic the sr isotopic composition in the unaltered portions of calcitic megafossils has potential as a stratigraphie tool

paired li ca and δ18o peaks in bivalve shells from the gulf of panama mark seasonal coastal upwelling abstract paired lithium to calcium li cashell and oxygen isotope 18oshell ratios were measured in four aragonitic megapitaria aurantiaca bivalve shells from the tropical eastern pacific and evaluated with respect to their linkage to seasonal coastal upwelling the li cashell and 18oshell of two specimens from the upwelling dominated gulf of panama are positively correlated and consistently reveal large seasonal variations of up to 300 mol mol and 3 respectively the li cashell and 18oshell of two shells from the adjacent non upwelling gulf of chiriqui are not correlated and show a reduced seasonal variability rarely exceeding 20 mol mol and 1 0 respectively in some m aurantiaca specimens the li cashell shows a weak positive correlation with growth increment width indicating that physiological growth rate effects might in part control the background li cashell unambiguous seasonal 18oshell signals used for a precise chronology for a live collected specimen from the gulf of panama imply that distinct parallel peaks in li cashell and 18oshell mark the cold and highly productive coastal upwelling season during february to april a comparison with environmental data reveals a negative correlation between li cashell and water temperature and a strong positive correlation between li cashell and chlorophyll a in the gulf of panama while a causal link between li cashell and temperature remains uncertain we argue that li cashell peaks in m aurantiaca are consistent with the concept of an incorporation of additional li provided by diatom dominated phytoplankton blooms during coastal upwelling our findings suggest that li cashell in m aurantiaca may serve as a new proxy for seasonal coastal upwelling the potential of which should be tested for other mollusk species and upwelling regions

mollusc and brachiopod skeletal hard parts intricate archives of their marine environment the biogenic carbonate hard parts of fossil bivalves cephalopods and brachiopods are among the most widely exploited marine archives of phanerozoic environmental and climate dynamics research the advent of novel analytical tools has led many workers to explore non traditional geochemical and petrographic proxies and work performed in neighbouring disciplines sheds light on the complex biomineralization strategies applied by these organisms these considerations form a strong motivation to review the potential and problems related to the compilation and interpretation of proxy data from bivalve cephalopod and brachiopod hard parts from the viewpoint of the sedimentologist and palaeoceanographer specific focus is on the complex biomineralization pathways of a given dissolved ion or food particle from its aquatic environment via the digestion and biomineralization apparatus in molluscs and brachiopods and its incorporation into a biomineral given that molluscs and brachiopods do not secrete their hard parts from seawater but rather from their mantle and periostracum this paper evaluates differences and similarities of seawater versus that of body fluids cephalopods bivalves and brachiopods exert a strong biological control on biomineralization that to some degree may buffer their shell geochemistry against secular changes in seawater chemistry disordered amorphous calcium carbonate precursor phases later transformed to crystalline biominerals may be significant in carbonate archive research due to expected geochemical offset relative to the direct precipitation of stable phases a reasonable level of understanding of the related mechanisms is thus crucial for those who use these skeletal hard parts as archives of the palaeo environment the impact of what is commonly referred to as biological factors on the geochemistry of mollusc and brachiopod hard parts is explored for conventional isotope systems such as carbon oxygen strontium and traditionally used element to calcium ratios in particular the often used 13ccarb or the mg ca and sr ca elemental proxies are fraught with problems an interesting new research field represents the analysis calibration and application of non traditional proxies to mollusc and brachiopod hard parts examples include the carbonate clumped isotope 47 approach and the analysis of the isotopes of ca mg n li s or element to ca ratios such as li ca or b ca and rare earth elements based on considerations discussed here a series of do s and don ts in mollusc and brachiopod archive research are proposed and suggestions for future work are presented in essence the suggestions proposed here include experimental work also field experiments making use of recent archive organisms or where possible a reasonable recent analogue in the case of extinct groups moreover the detailed understanding of the architecture of mollusc and brachiopod hard parts and their ultra structures must guide sampling strategies for geochemical analyses where feasible a detailed understanding of the diagenetic pathways and the application of multi proxy and multi archive approaches should form the foundation of fossil carbonate archive research the uncritical compilation of large data sets from various carbonate shelled organisms collected at different locations is not encouraged

cadmium zinc copper and barium in foraminifera tests the concentrations of cadmium zinc copper and barium have been determined on 2 mg samples of single species foraminifera populations cleaning techniques were tested using north atlantic core tops and followed by a detailed downcore study for the last 30 000 years in south atlantic core v22 174 raw foram tests cleaned by crushing followed by ultrasonic removal of fine grained material and dissolved in a ph 5 5 acetate buffer contain appreciable amounts of trace elements associated with ferromanganese and alumino silicate contaminants a reductive complexing cleaning treatment reduces ferromanganese contamination by 1 2 orders of magnitude acetate buffers at ph 5 5 complex iron and raise the solubility of ferromanganese oxides these buffers are unsuitable for separating carbonate lattice bound trace elements from the fraction associated with ferromanganese phases improved mechanical and ultrasonic reductive cleaning combined with a mild dissolution in distilled water under 1 atm pco2 reduces contaminant levels another order of magnitude the cd and zn concentrations order 10 8 mole cd mole ca and 10 5 mole zn mole ca of species with low surface area show an increase with decreasing isotopic temperatures this increase is consistent with the increasing concentrations of these metals from low values in surface waters to higher values at depth the variance of cd and zn over the last 30 000 years in the central south atlantic is consistent with the probable variability of the dissolved trace elements at the calcification levels of the species analyzed cu and ba are irreproducible and probably sensitive to residual contaminant phases the trace element content of the tests differs from levels observed in a recent coprecipitation study foraminifera may be a significant vector in zinc cycling in the ocean

earthquake early warning shakealert in the pacific northwest we evaluate the performance of earthquake early warning algorithm elarms 2 earthquake alarm system v 2 in the pacific northwest real time and prerecorded seismic data from oregon california and washington in the united states and british columbia in canada are used the earthquakes tested range up to moment magnitude 7 2 the limit for which the elarms 2 magnitude method is accurate elarms 2 reliably detects catalog magnitude 3 and larger earthquakes within the network but the cut off magnitude for accurate event recognition is higher for events offshore and on the edges of the network we have made several adjustments that make the elarms 2 algorithm less likely to falsely report multiple alerts for earthquakes replaying of past earthquakes shows that the new settings improve the algorithm s behavior for edge cases while not degrading previously well constrained solutions within the dense part of the network we expect few false alerts none that would predict significant shaking anywhere in our region even though elarms 2 assumes a fixed earthquake depth the epicenter and magnitude estimates are accurate enough to provide good predictions of shaking intensities online material tables listing parameters of 31 calibration earthquakes elarms 2 real time detections and comparison of elarms 2 performance for calibration events before and after adjusting configuration

real time centroid moment tensor determination for large earthquakes from local and regional displacement records summary we present an algorithm to rapidly determine the moment tensor and centroid location for large earthquakes employing local and regional real time high rate displacement records from gps the algorithm extracts the coseismic offset from the displacement waveforms and uses the information to invert for the moment tensor the green s functions for a layered earth are obtained numerically from open source code edgrn to determine the centroid multiple inversions are simultaneously performed within a grid of inversion nodes and the node with the smallest misfit is then assigned the centroid location we show results for two large earthquakes replayed in simulated real time mode using recorded 1 hz gps displacements the 2003 mw 8 3 tokachi oki and the 2010 mw 7 2 el mayor cucapah earthquakes we demonstrate that it is feasible to obtain accurate cmt solutions within the first 2 3 min after rupture initiation without any prior assumptions on fault characteristics demonstrating an order of magnitude improvement in latency compared to existing seismic methods for the two earthquakes studied this methodology is useful for rapid earthquake response tsunami prediction and as a starting point for rapid finite fault modelling

stable isotope variations in modern articulate brachiopods abstract carbon and oxygen isotopic analyses were performed on several species of holocene articulate brachiopods from various locations in the caribbean sea and in the atlantic and pacific oceans from salinities ranging between 30 and 38 pmil and over a temperature range from 4 to 28 c 39 to 82 f the dgr18o of articulate brachiopods are systematically related to the dgr18o and temperatures of the ambient waters lowenstam in 1961 concluded that articulate brachiopods secrete calcium carbonate low magnesium calcite in isotopic equilibrium with the surrounding waters the data compiled in this study along with that of lowenstam closely approximate the equilibrium calcite water end page 500 line deviation from apparent equilibrium was most evident for samples from a few cold water sites intraspecific isotopic variations in several warmer water assemblages were up to 2 pmil and isotopic variation within individual specimens as high as 1 5 pmil were noted articulate brachiopods were not separable at any taxonomic level on the basis of ranges in isotopic values the two extant orders of brachiopods the terebratulida and the rhynchonellida as well as the suborder thecideidina had essentially equivalent isotopic ranges at any given locality thus there is no evidence for significant taxonomic control of oxygen isotope fractionation among articulate brachiopods no correlation appears to exist between dgr18o and dgr13c values our results suggest strongly that isotopic data from small populations or communities of well preserved articulate brachiopods can be used in paleogeographic and paleo oceanographic reconstructions end of article last page 501

effect of environmental conditions and skeletal ultrastructure on the li isotopic composition of scleractinian corals the lithium isotope compositions li 7 li 6 and li ca ratios of shallow water and deep sea corals porites lutea cladocora caespitosa lophelia pertusa and desmophyllum cristagalli were measured using a cameca ims 1270 ion microprobe the two c caespitosa samples were grown under controlled conditions at co2 partial pressures pco 2 of 416 29 mu atm and 729 30 mu atm respectively in situ analyses show that all samples are isotopically homogeneous within analytical precision 1 1 parts per thousand 1 sigma and display significantly lower delta li 7 values relative to seawater indicating a significant isotope fractionation during aragonite formation in contrast to all other elements analysed so far there is no relationship between the li isotopic compositions and the skeletal ultrastructure however li ca does show variation correlated with ultrastructure albeit with significant differences between species this implies that the bio mineralization mechanisms which are supposed to be different for the different skeletal components do not influence the li isotopic composition in corals in particular the model of rayleigh fractionation in a semi enclosed calcifying fluid is incompatible with the homogeneity of the li isotope compositions at the micrometer scale we also show that changes in pco 2 and ph do not significantly affect the li isotope signature nevertheless a small but significant and systematic difference in li isotopic composition is observed between deep sea azooxanthellate and shallow water zooxanthellate corals the lack of dependence on ph and pco 2 and on skeletal ultrastructure indicates that the u isotopic signature of corals could be used as a proxy for reconstructing the paleo delta li 7 of seawater and potentially for deconvolving past continental weathering rates c 2009 elsevier b v all rights reserved

in situ δ7li li ca and mg ca analyses of synthetic aragonites in situ secondary ion mass spectrometry sims analyses of 7li li ca and mg ca were performed on five synthetic aragonite samples precipitated from seawater at 25 c at different rates the compositions of 7li in bulk aragonites and experimental fluids were measured by multicollector inductively coupled plasma mass spectrometry mc icp ms both techniques yielded similar 7li in aragonite when sims analyses were corrected to calcium carbonate reference materials fractionation factors 7li 6li range from 0 9895 to 0 9923 which translates to a fractionation between aragonite and fluid from 10 5 to 7 7 the within sample 7li range determined by sims is up to 27 exceeding the difference between bulk 7li analyses of different aragonite precipitates moreover the centers of aragonite hemispherical bundles spherulites are enriched in li ca and mg ca relative to spherulite fibers by up to factors of 2 and 8 respectively the li ca and mg ca ratios of spherulite fibers increase with aragonite precipitation rate these results suggest that precipitation rate is a potentially important consideration when using li isotopes and elemental ratios in natural carbonates as a proxy for seawater composition and temperature

the 2014 m w 6 0 napa earthquake california observations from real time gps enhanced earthquake early warning recently progress has been made to demonstrate feasibility and benefits of including real time gps rtgps in earthquake early warning and rapid response systems most concepts however have yet to be integrated into operational environments the berkeley seismological laboratory runs an rtgps based finite fault inversion scheme in real time this system g larms detected the 2014 mw 6 0 south napa earthquake in california we review g larms performance during this event and 13 aftershocks and present rtgps observations and real time modeling results for the main shock the first distributed slip model and magnitude estimates were available 24 s after the event origin time which after optimizations was reduced to 14 s 8s s wave travel time 6 s data latency g larms solutions for the aftershocks that had no measurable surface displacements demonstrate that in combination with the seismic early warning magnitude m w 6 0 is our current resolution limit

li ca ratios of ostracod shells at lake qinghai ne tibetan plateau china a potential temperature indicator acquiring continuous and high resolution natural records in recent 2 000 years is the hot issue in the palaeoclimate research recent studies revealed that li ca and mg li ratio of carbonate is a potential tracer of past environmental changes in the oceans and is seldom applied for palaeoclimate reconstruction in lakes to make full understanding of the potential of li ca ratios of carbonates in lakes li ca ratios of monospecific ostracod shell eucypris inflate with similar size in the lacustrine sediment core from lake qinghai ne tibetan plateau have been analysed for the first time single species can effectively avoid the interspecies effects in combination with the sedimentation rate that existed data derived from 210pb and 137cs downcore variations of li ca ratios of ostracod shells during the past 800 years in lake qinghai have been reconstructed successfully by comparing li ca ratios and temperature inferred from meteorological records and tree ring widths in dulan and qilianshan in adjacent regions li ca ratios of ostracod shells negatively correlate with temperature higher temperature corresponds with lower li ca ratios and vice versa indicating that li ca ratio of ostracod shells is an effective indicator for temperature variations therefore ongoing in depth investigation using li ca ratios of carbonates in more lakes to further reveal its palaeotemperature implications would be deserved

brachiopods as indicators of original isotopic compositions in some paleozoic limestones the original stable isotopic composition of paleozoic marine carbonate rocks is important to establish a baseline for evaluating diagenetic alteration and providing a reliable data base for modeling exogenic geochemical cycles of the elements we have compared the 18 o and 13 c values in the nonluminescent portions of brachiopods with similar published data of whole brachiopods other whole fossils and estimates of original isotopic composition of marine cements the oxygen and carbon isotopic records for each of these paleozoic components show generally good internal consistency significant discrepancies however were noted between results on the different components isotopic and trace element data presented in this study suggest that permo carboniferous whole brachiopods are little altered chemically nonetheless a more reliable but not fool proof approach for obtaining pristine isotopic values is microsampling of least altered regions based on cathodoluminescence in conjunction with staining techniques and elemental analyses the carbon and oxygen isotopic compositions of all components decrease in 18 o and 13 c in geologically older material neither temporal trend is monotonic however oxygen isotopic results suggest an important positive shift in 18 o of about 2 during the early carboniferous whereas the carbon isotope trend shows a major positive shift 2 3 during the mid carboniferous

application of real time gps to earthquake early warning 1 we explore the use of real time high rate gps displacement data for earthquake early warning using 1 hz displacement waveforms from the april 4 2010 mw 7 2 el mayor cucapah earthquake we compare these data to those provided by the broadband velocity and accelerometer instrumentation of the southern california seismic network the unique information provided by the gps based displacement timeseries is the permanent static displacement using a simple algorithm that can be applied in real time we extract the static offset shortly after the s wave arrival around the time of the observed peak shaking at the same site and before shaking at more distant locations these data can be used as they become available to provide a robust estimate of the earthquake magnitude which ranges from 6 8 to 7 0 in this case we therefore conclude that real time high rate gps can provide a useful and independent assessment of earthquake magnitude for the purpose of earthquake early warning and real time earthquake information systems in general including tsunami warning systems

the utility of gnss for earthquake early warning in regions with sparse seismic networks abstract real time global navigation satellite systems gnss data are on their way to being well integrated into earthquake early warning eew systems the strength of gnss data lies in the resolution of large dynamic and static displacements because of the limits in precision gnss data alone cannot resolve small ground displacements due to for instance p waves therefore their use is currently limited to refining early warnings with more precise earthquake characteristics such as magnitudes or ground motion predictions here we analyze 1 hz global positioning system gps data from the 24 january 2016 m w 7 1 iniskin earthquake which ruptured 125 km under cook inlet in alaska to motivate the inclusion of gnss derived s wave measurements into the trigger algorithms of eew systems in regions lacking dense early warning instrumentation networks we derive a relationship between earthquake depth and distance to help determine whether gnss s wave observations could expedite warnings to specific locations because the iniskin earthquake was deep by the time the s wave reached the surface the p wave had already been observed over a wide region limiting the potential for unique contributions from gnss data to this event for the same earthquake occurring near the surface however s waves derived from gnss data have the potential to increase the warning time regardless of the depth the iniskin earthquake is an excellent example of the utility of gnss in rapidly assessing the magnitude improving predictions of ground shaking and estimating the area of impact for the earthquake

partial diagenetic overprint of late jurassic belemnites from new zealand implications for the preservation potential of δ7li values in calcite fossils the preservation potential and trends of alteration of many isotopic systems e g li mg ca that are measured in fossil carbonates are little explored yet extensive paleoenvironmental interpretations have been made on the basis of these records here we present a geochemical dataset for a late jurassic 153 ma belemnite belemnopsis sp from new zealand that has been partially overprinted by alteration we report the physical pathways and settings of alteration the resulting elemental and isotopic trends including 7li values and li ca ratios and assess whether remnants of the primary shell composition have been preserved or can be extrapolated from the measured values the 18o and 13c values as well as sr ca and mn ca ratios were analysed along two profiles in addition 6 samples were analysed for 87sr 86sr sr ca and mn ca ratios five samples from the same specimen and 2 from the surrounding sediment were analysed for 7li values li ca sr ca and mn ca ratios and are compared to results for 6 other late jurassic belemnite rostra belemnopsis sp andhibolithes sp from the same region the 87sr 86sr ratios are lower less radiogenic in the most altered part of the rostrum whereas 7li values become more positive with progressive alteration the direction and magnitude of the trends in the geochemical record indicate that one main phase of alteration that occurred in the late cretaceous caused most of the diagenetic signature in the calcite despite relatively deep burial down to 4 km and thus elevated temperatures this diagenetic signature has subsequently been preserved even for the highly mobile element lithium suggesting that primary lithium isotope values can be maintained over geological timescales at least in thick macrofossil shells our best 7li estimate for pristine late jurassic 155 148 ma belemnites is 27 1 which points to a late jurassic seawater 7li of 29 32 compatible with the modern value of 31

the value of real time gnss to earthquake early warning gnss based earthquake early warning eew algorithms estimate fault finiteness and unsaturated moment magnitude for the largest most damaging earthquakes because large events are infrequent algorithms are not regularly exercised and insufficiently tested on few available datasets we use 1300 realistic time dependent synthetic earthquakes on the cascadia megathrust to rigorously test the geodetic alarm system solutions are reliable once six gnss stations report static offsets which we require for a first alert median magnitude and length errors are 0 15 0 24 units and 31 40 for the first alert and 0 04 0 11 units and 7 31 for the final solution we perform a coupled test of a seismic geodetic eew system using synthetic waveforms for a mw8 7 scenario seismic point source solutions result in severely underestimated pga geodetic finite fault solutions provide more accurate predictions at larger distances thus increasing warning times hence gnss observations are essential in eew to accurately characterize large out of network events and correctly predict ground motion

geochemistry of brachiopods oxygen and carbon isotopic records of paleozoic oceans abstract combined trace element and isotope studies of 319 brachiopods covering the ordovician to permian time span show that 13c and 18o in well preserved specimens varied during the paleozoic the overall 13c secular trend is in accord with the previously published observations but its details are obscured by vital isotopic fractionation effects at generic level nonetheless the results suggest that the negative correlation between marine 13ccarbonate and 34ssulphate deteriorates at time scales of 106 years due to the long residence time and thus slow response of so42 in the ocean for oxygen isotopes all devonian and older specimens have 18o of 4 while the well preserved permian samples have near present day 18o of about 1 pdb this isotopic dichotomy is probably not due to post depositional phenomena salinity or biogenic fractionation effects this leaves open the perennial arguments for a change in 18 o 16 o of sea water versus warmer ancient oceans the present data are difficult to explain solely by the temperature alternative the coincidence of the proposed shift in 18o with the large late paleozoic changes in marine 87 sr 86 sr 13 c 12 c 34 s 32 s and sea level stands argues for a tectonic cause and for a change in 18 o 16 o of sea water although such explanation is difficult to reconcile with global balance considerations and with isotopic patterns observed in alteration products of ancient basalts and ophiolites whatever the precise cause or combination of causes the implications for tectonism and or paleoclimatology are of first order significance

sr and nd isotopes at the prmian triassic boundary a record of climate change abstract we present a detailed curve of seawater 87sr 86sr for the middle permian to triassic based on analyses of conodonts from overlapping sections in the u s a pakistan correlated using conodont biostratigraphy the isotope ratio decreased in the middle permian at an average rate of 0 000062 ma 1 reached a minimum in the capitanian 257 258 ma and increased in the late permian at an average rate of 0 000097 ma 1 the late permian rate of increase was roughly two and a half times greater than the average increase over the past 40 ma and approximately equal to the highest cenozoic rates which occurred over much shorter time intervals modeling results suggest that decreasing middle permian 87sr 86sr ratios were driven by changes in the riverine sr flux to the oceans while increasing ratios in the late permian triassic are attributed to both increased riverine 87sr 86sr and flux the reduced middle permian riverine flux coincides with extreme continental aridity associated with the formation of pangea and recorded by massive evaporite deposits in addition mountains in the equatorial region of pangea may have created a rain shadow thereby minimizing precipitation in regions that currently contribute the bulk of chemical weathering products to the ocean increasing riverine 87sr 86sr in the late permian is suggested by the observation that 143nd 144nd values decrease at the same time however the source of radiogenic sr is not known frequently cited mechanisms for increasing 87sr 86sr in runoff such as glaciations and continent to continent collisions coincide instead with decreasing seawater 87sr 86sr in the middle permian one possible source may have been deep erosion into older orogens associated with a dramatic increase in chemical weathering in the late permian the cause of enhanced weathering appears to have been increased levels of atmospheric co2 with associated global warming and increased humidity proposed sources of co2 include dissociation of gas hydrates and oxidation of organic matter during extreme sea level regression as well as volcanic emissions from siberian traps eruptions continental floral and faunal distributions are consistent with this interpretation as are oceanic 13c patterns and variations in shallow water sediment lithologies

li ca enrichments in great scallop shells pecten maximus and their relationship with phytoplankton blooms article i nfo phytoplankton dynamics in coastal oceans is a major component of the global biogeochemical carbon cycle and is currently affected by global change through modifications in levels of primary productivity and com position of phytoplankton communities despite many attempts no straightforward geochemical proxy has been found yet in marine biogenic carbonates for reconstruction of past phytoplankton dynamics with high temporal resolution here we report on sub weekly variations of lithium to calcium ratios li cashell along the axis of maximum growth of great scallop shells pecten maximus collected alive between 1999 and 2007 in the bay of brest northwest france inter individual variability of li cashell time series was very low suggesting an environmental control on the incorporation of li within shells conversely inter annual variability of li cashell was high with limited seasonal li cashell variations in 2001 and 2007 and the presence of li enrichments from may to july in 1999 and 2004 comparison of these results with shell growth measure ments increment width and environmental parameters suggests i that shell calcification rate is likely the main factor controlling incorporation of li in pecten maximus shell calcite ii that seawater temperature has only a weak positive influence on li cashell of this species over the range 8 18 c and iii that during diatom blooms additional amounts of li may be trapped in the shell following dissolution of li rich frustules of ed ible species in the digestive tract of scallops being responsible for li cashell peaks therefore we suggest that li cashell ratio may be a novel proxy for timing and magnitude of diatom blooms in coastal ecosystems anal ysis of ancient shells may thus provide useful information on past phytoplankton dynamics and on the im portance of recent shifts observed from diatoms to non siliceous phytoplankton in coastal areas affected by anthropogenic activities

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

lithium to calcium ratios in modern cenozoic and paleozoic articulate brachiopod shells li ca ratios in modern brachiopod shells generally correlate inversely with growth temperature ranging from 20 mol mol at 30 c to 50 mol mol at 0 c with no apparent interspecific offsets causes of the temperature effect on li ca ratios are not yet understood cenozoic brachiopod li ca ratios average 30 mol mol similar to the average observed in modern brachiopods relatively constant li ca ratios for eocene to pleistocene nonluminescent brachiopod shells consistent with previous observations of cenozoic planktonic foraminifera support the conclusion of little variation in cenozoic seawater li ca nonluminescent portions of permian and carboniferous brachiopods have li ca ratios substantially lower generally 10 mol mol than modern cenozoic or devonian samples mass balance considerations constrained by 18o of brachiopods suggest that low li concentrations in permo carboniferous seawater could be the result of a lower flux of dissolved li from the continents and or a higher flux of li from seawater to clastic marine sediments nonluminescent devonian brachiopods from a single hand specimen have li ca ratios around 70 of the modern average these li ca ratios can be explained by either somewhat higher temperature with constant seawater li ca somewhat lower seawater li ca at constant temperature or a combination of slightly elevated temperature and slightly lower seawater li ca

lithium in the aragonite skeletons of massive porites corals a new tool to reconstruct tropical sea surface temperatures previous studies have demonstrated the potential for the li content of coral aragonite to record information about environmental conditions but no detailed study of tropical corals exists here we present the li and mg to ca ratios at a bimonthly to monthly resolution over 25 years in two modern porites corals the genus most often used for paleoclimate reconstructions in the tropical indo pacific a strong relationship exists between coral li ca and locally measured sst indicating that coral li ca can be used to reconstruct tropical sst variations however li ca ratios of the skeleton deposited during 1979 1980 do not track local sst well and are anomalously high in places the mg ca ratios of this interval are also anomalously high and we suggest li ca can be used to reconstruct tropical sst only when mg ca data are used to carefully screen for relatively rare biological effects mg li or li mg ratios provide little advantage over li ca ratios except that the slope of the li mg temperature relationship is more similar between the two corals the mg li temperature relationship for the coral that experienced a large temperature range is similar to that found for cold water corals and aragonitic benthic foraminifera in previous studies the comparison with data from other biogenic aragonites suggests the relationship between li mg and water temperature can be described by a single exponential relationship despite this hint at an overarching control it is clear that biological processes strongly influence coral li ca and more calibration work is required before widely applying the proxy

li sr mg and na in foraminiferal calcite shells from laboratory culture sediment traps and sediment cores abstract constant temperature laboratory culture experiments of the planktonic foraminiferal species globigerinoides sacculifer brady suggest that the ratios of li and sr to ca in the shells are a function of these ratios in the culture solutions mg ca and na ca in the shells did not vary with changes of these ratios in the culture solution these are the first direct determinations of the relationship between foraminiferal shell chemistry and solution composition the possibility of temperature dependence for the minor elemental composition of foraminiferal shells was also investigated in the laboratory and by analysis of several planktonic and one benthic foraminiferal species from sediment trap and sediment core samples the sr ca mg ca and na ca ratios in the natural samples roughly correlate with calcification temperature whereas differences in the li ca ratios are small and not systematically related to temperature however laboratory culture experiments at 20 c and 30 c showed no variation in the li ca sr ca mg ca and na ca ratios with calcification temperature for the planktonic foraminifera g sacculifer and orbulina universa therefore observed differences in the sr ca mg ca and na ca ratios for the sediment trap and core foraminiferal samples cannot be ascribed to direct effects of calcification temperature but may be due to some other environmental factor which is correlated with temperature

investigating triggering of the aftershocks of the 2014 napa earthquake abstract the occurrence of the m w 6 0 south napa california earthquake on 24 august 2014 at 03 20 a m local time triggered discussion in the seismological community about the level of damage associated with such a moderate magnitude event and about the geometry and orientation of the causative fault in addition coulomb static stress change mapping does not seem to be able to fully explain near source aftershock distribution here we find clear evidence of a north northwest source directivity from the analysis of the spatial distribution of peak ground motion the area of the highest values of the estimated peak dynamic strain field computed accounting for fault extent and source directivity agrees with the near source aftershock distribution this might suggest that in addition to coulomb static stress change dynamic strain also contributed to the triggering of near source napa earthquake aftershocks the approach used here might be useful to identify areas likely prone to aftershock occurrence

18o16o and 13c12c in lower paleozoic articulate brachiopods implications for the isotopic composition of seawater three hundred and eleven articulate brachiopods with extensive geographic coverage spanning the cambrian to silurian stratigraphic interval were analyzed for oxygen and carbon isotopic composition cambrian samples have 18o 7 ordovician samples 2 4 and silurian samples 1 9 confirming the previously established trend towards lighter isotopic compositions with increasing age throughout the lower paleozoic forty nine best preserved ordovician and silurian samples were identified based on scanning electron microscopy and trace element analysis they were found to bracket the isotopic compositions of over 85 of specimens from these stratigraphic intervals supporting widespread preservation of the isotopic signal some latest ordovician and lower ludlovian samples associated with shale sequences are apparently enriched in 18o these are interpreted as an environmental phenomenon perhaps related to water temperature and glaciation a number of silurian samples of varying genera and stratigraphic levels are highly enriched in 13c up to 6 some are shale related but some are associated with carbonate bearing basins these are also thought to represent near original compositions but a single environmental cause is unknown the present data show that luminescence is not a decisive criterion for evaluating the degree of brachiopod preservation whole shell values were isotopically similar to their nonluminescent portions for both oxygen and carbon

finder v 2 improved real time ground motion predictions for m2 m9 with seismic finite source characterization recent studies suggest that small and large earthquakes nucleate similarly and that they often have indistinguishable seismic waveform onsets the characterization of earthquakes in real time such as for earthquake early warning therefore requires a flexible modeling approach that allows a small earthquake to become large as fault rupture evolves over time here we present a modeling approach that generates a set of output parameters and uncertainty estimates that are consistent with both small moderate m6 5 and large earthquakes m6 5 as is required for a robust parameter interpretation and shaking forecast our approach treats earthquakes over the entire range of magnitudes m2 as finite line source ruptures with the dimensions of small earthquakes being very small 100 m and those of large earthquakes exceeding several tens to hundreds of kilometres in length the extent of the assumed line source is estimated from the level and distribution of high frequency peak acceleration amplitudes observed in a local seismic network high frequency motions are well suited for this approach because they are mainly controlled by the distance to the rupturing fault observed ground motion patterns are compared with theoretical templates modeled from empirical ground motion prediction equations to determine the best line source and uncertainties our algorithm extends earlier work by bose et al for large finite fault ruptures this paper gives a detailed summary of the new algorithm and its offline performance for the 2016 m7 0 kumamoto japan and 2014 m6 0 south napa california earthquakes as well as its performance for about 100 real time detected local earthquakes 2 2 m 5 1 in california for most events both the rupture length and the strike are well constrained within a few seconds 10 s of the event origin in large earthquakes this could allow for providing warnings of up to several tens of seconds the algorithm could also be useful for resolving fault plane ambiguities of focal mechanisms and identification of rupturing faults for earthquakes as small as m2 5

δ18o and δ13c values of modern brachiopod shells abstract researchers have not rigorously tested the hypothesis that calcite from modern brachiopod shells is precipitated in oxygen isotope equilibrium with ambient seawater isotopic variability at the intraspecimen and intertaxon levels has not been examined without such data for modern brachiopods similar data from ancient brachiopods cannot be accurately interpreted in this study a survey is made of 18 o and 13 c values of terebratulid rhynchonellid thecideidine and craniacean brachiopods from antarctica the bay of fundy curacao japan new zealand norway puget sound palau sicily and south africa this suite of samples provides a wide range of taxonomic levels temperatures salinities and depositional environments for evaluating the degree of isotopic equilibrium attained during precipitation of brachiopod calcite new data indicate that modem brachiopod calcite is not always precipitated in oxygen and carbon isotope equilibrium with ambient seawater calcite from the primary layer and specialized shell structures hinge brachidium foramen interarea muscle scars are depleted in both 18 o and 13 c a characteristic of biological fractionation or vital effects often found in other calcerous marine organisms our findings suggest that these portions of the brachiopod shell should be avoided during sampling of ancient brachiopods secondary layer calcite the material most often analyzed in ancient brachiopods has higher 18 o and 13 c values which approach and sometimes correspond with predicted equilibrium values therefore secondary layer calcite is the most suitable portion of the brachiopod shell for use as an ancient seawater proxy although near equilibrium precipitation in secondary layer calcite is encouraging to those studying the isotopic composition of ancient oceans these data come with caveats large intraspecimen variability in the 18 o values of secondary layer calcite 1 in some samples limits the use of brachiopods as precise indicators of the 18 o value or temperature of ancient seawater the 18 o and 13 c values of secondary layer calcite deviate from predicted equilibrium values toward the lower values of the primary layer and specialized shell structures indicating a measurable vital effect in most cases measured 18 o values are lower than the calculated equilibrium values dictated by seasonal variations in the 18 o value and temperature of seawater ontogenetic variations in the 13 c values of secondary layer calcite have also been measured and must be assessed when interpreting ancient data modern brachiopods occur in a wide range of seawater salinities and temperatures therefore the relation between salinity and the 18 o value of seawater must be known to correctly calculate the temperature of calcite precipitation from secondary layer 18 o values errors of up to 15 c are found if ambient seawater is assumed to have a constant 18 o value e g 0 smow and the 18 o values of secondary layer calcite are used to calculate temperature coupled with vital effects and intraspecimen variability these errors can obscure the resolution of secular variations in the rock record

investigation of li ca variations in aragonitic shells of the ocean quahog arctica islandica northeast iceland interannual and intra annual variations in lithium to calcium ratio were investigated with high temporal resolution in the aragonitic outer shell layer of juvenile arctica islandica mollusca bivalvia collected alive in 2006 off northeast iceland li ca shell ranged between 7 00 and 11 12 mol mol 1 and presented well marked seasonal cycles with minimum values recorded at the annual growth lines a general pattern was a progressive increase in li ca shell from march to may followed by a plateau in june and a decrease down to minimum values in july august li ca shell was correlated with d 18 o shell derived temperature but the strength of this relationship was weak r 2 p shell in a islandica may most likely be explained 1 by calcification rate and or 2 by significant river inputs of li rich silicate particles flowing to the sea as soon as snow melts in the first case li ca shell may be a useful proxy for addressing seasonal variations of growth rate in bivalves that lack discernable microgrowth patterns abrupt decreases of li ca shell may in turn help identify growth retardations due to harsh environmental conditions alternatively if li ca shell variations are linked to particulate li inputs by rivers this could be a new proxy for the intensity of mechanical weathering of icelandic basalts with interesting perspectives for the reconstruction of frequency and intensity of past jokulhlaups subglacial outburst floods further works including experimental studies are needed to test these hypotheses