quantification of tsunamigenic earthquakes by the mt scale abstract a magnitude scale m t previously defined by the author is unique among the many scales in seismology because it is based on the instrumental amplitude of tsunami waves its level being adjusted to agree with moment magnitude despite the simple definition the m t scale reliably measures the seismic moment of an earthquake as well as the overall physical size of the source of the tsunami in reality the seismic moment estimated from m t for 39 events around japan is found to be essentially equivalent to that estimated from seismic waves with an uncertainty factor of two on average the m t scale is useful for a quantitative discrimination of tsunami earthquakes that generate anomalously large tsunamis for their magnitude of 97 tsunamigenic events that occurred around japan during the period 1894 to 1985 at least eight tsunami earthquakes are identified from the m t vs m s relation

neritic and pelagic carbonate sedimentation in the marine environment ignorance is not bliss synthesis of available data allows us to define general patterns of late quaternary carbonate production and sedimentation in the global ocean during high stands of sea level the neritic and pelagic environments appear to sequester approximately similar amounts of carbonate whereas during low stands of sea level the decreased neritic zone produces and accumulates approximately an order of magnitude less carbonate assuming that global accumulation of deep sea carbonates remains more or less constant during glacially induced changes in sea level the ocean becomes depleted with respect to calcium carbonate during high stands and recharges during low stands before we can achieve a better understanding of the global carbonate system however we need a better understanding of key environments and processes a production and accumulation on continental shelves both as potential sinks accumulation and as sources export to the deep sea b a better measure of pelagic carbonate production and c late quaternary late pleistocene and holocene mass accumulation rates in the deep sea

a combined earthquake landslide source model for the tsunami from the 27 november 1945 mw 8 1 makran earthquake the tsunami of 27 november 1945 from an m w 8 1 earthquake in the makran subduction zone is the only instrumentally recorded and deadly tsunami in the northwest indian ocean offshore iran pakistan oman and india despite the fact that some source models have been proposed based on seismic or far field tsunami data none of them was able to reproduce one important observation near field runup of 10 12 m here we applied numerical modeling and examined three possible secondary sources 1 splay faulting 2 delayed rupture of the earthquake source and 3 submarine landslides these secondary sources were added to the existing state of the art earthquake source for this tsunami results of simulations revealed that only a submarine landslide with dimensions of 15 km length 15 km width a thickness of 600 m a volume of 40 km3 and located at 63 0 e 24 8 n is capable of reproducing the near field tsunami observation such a combined earthquake landslide source is consistent with all available observations including far field tsunami waveforms in karachi pakistan and mumbai india with near field runup height of 10 12 m coastal coseismic deformation data in pasni subsidence and ormara uplift 1 3 m and earthquake magnitude m 8 0 8 3 electronic supplement 1 tables listing parameters of the splay fault and landslide scenarios and figures showing deformation and coastal tsunami amplitudes from splay fault and landslide scenarios 1 http www bssaonline org lookup suppl doi 10 1785 0120160196 dc1

centroid moment tensor solutions for july september 1998 abstract centroid moment tensor solutions are presented for 214 earthquakes that occurred during the third quarter of 1998 the solutions are obtained using corrections for aspherical earth structure represented by a whole mantle shear velocity model sh8 u4l8 of dziewonski and woodward dziewonski a m woodward r l 1992 acoustic imaging at the planetary scale in emert h harjes h p eds acoustical imaging plenum new york 19 785 797 a new model of anelastic attenuation of durek and ekstrom durek j j ekstrom g 1996 a radial model of anelasticity consistent with long period surface wave attenuation bull seism soc am 86 144 158 is used to predict the decay of the waveforms

bottom response to a tsunami earthquake submersible observations in the epicenter area of the 1993 earthquake off southwestern hokkaido sea of japan we conducted a research campaign of nine dives using the manned submersible vehicle shinkai 6500 in 1995 beneath the central okushiri ridge along the eastern margin of the sea of japan the main objective was to investigate coseismic response and bottom disturbance to the tsunamigenic 1993 offshore southwestern hokkaido earthquake ms 7 8 42 47 n 139 12 e in the northern aftershock area including the mainshock epicenter the whole aftershock area occupies the western half of source area of the related tsunami between the okushiri ridge and the neighboring shiribeshi trough to the east we found a gentle scarplet of the earthquake fault that bounds the first terrace and a zone of open gashes on the flat terrace a number of sand blows open cracks and other slope failures occupied the slope of the okushiri ridge on the uplifted hanging wall side of the tsunami source area some fractures and holes whose activity had ceased soon after the earthquake began to be buried by the 2 year accumulation of recent sediments in contrast the shiribeshi trough on the footwall of the fault and in the subsided domain of the tsunami source area suffered no remarkable disturbance other than gentle folding our submersible observations elucidated the seafloor response to tsunamigenic uplift of the hanging wall of a seismogenic thrust fault which displays the present time section of back thrusting with an embryonic subduction along the eastern margin of the sea of japan

a simplified 3 d navier stokes numerical model for landslide tsunami application to the gulf of mexico 1 a simplified three dimensional navier stokes 3 d ns model for two fluids water and landslide material mudslide is presented and validated with standard laboratory experiments dubbed tsunami3d tsunami solution using navier stokes algorithm with multiple interfaces is applied to a 3 d full scale landslide scenario in the gulf of mexico gom i e the east breaks underwater landslide the simplified 3 d ns model is conceived to be computationally efficient for tsunami calculations the simplification is derived from the large aspect ratio of the tsunami waves wavelength wave height and the selected computational grid that has a smaller aspect ratio this allows us to assume a horizontal fluid surface in each individual cell containing the interface air water air mudslide and water mudslide the tracking of fluid interfaces is based on the volume of fluid method and the surfaces are obtained by integrating the fluxes of each individual fluid cell along the water column in the momentum equation the pressure term is split into two components hydrostatic and nonhydrostatic the internal friction is solved in a simplified manner by adjusting the viscosity coefficient despite the simplification to get an efficient solution the numerical results agree fairly well with standard landslide laboratory experiments required by the national tsunami hazard mitigation program for tsunami model validation the numerical effect caused by using a sharp versus a diffusive water mudslide interface for a full scale landslide tsunami scenario is also investigated observations from this experiment indicated that choosing a sharp or diffusive interface seems to have no remarkable effect at early stages of the tsunami wave propagation last a large scale 3 d numerical simulation is carried out for the ancient gom s east breaks landslide by using the simplified model to calculate the early stages of the tsunami wave propagation

aragonite to calcite transformation during fresh water diagenesis of carbonates insights from pore water chemistry dissolved strontium and calcium concentrations in fresh water lenses fwl and associated mixing zones mz on two small holocene ooid sand islands in the schooner cays bahamas were monitored during a 1 yr period to quantitatively analyze the transformation of aragonite to calcite the observed characteristics of this mass transfer are functions of climate and hydrology aragonite to calcite transformation in all hydrologic zones is primarily associated with meteoric recharge the transformation occurs throughout the fwl and in the mz to relative salinities of 19 and 36 sea water on the two islands rates of transformation are rapid in all zones and are greatest in the fwl a limestone composed of 100 calcite should form from an aragonite precursor within 4 700 to 15 600 yr in the fwl and within 8 700 to 60 000 yr in the upper mz efficiencies of transformation can vary between hydrologic zones due to pco2 effects yet the efficiency of the entire system fwl mz is high 87 this indicates that most caco3 derived from aragonite dissolution is reprecipitated as calcite somewhere in the fresh water system or upper mixing zone co2 effects fresh water sea water mixing and the differing solubilities between aragonite and calcite all drive the mass transfer the latter is the most significant accounting for up to nine times more mass transfer than co2 effects and at least ten times more mass transfer than fresh water sea water mixing differing solubilities should also cause mass transfer to occur throughout the hydrologic cycle but it apparently becomes ineffective after the rainy season possibly due to the inhibition of calcite precipitation

sources of tsunami and tsunamigenic earthquakes in subduction zones we classified tsunamigenic earthquakes in subduction zones into three types earth quakes at the plate interface typical interplate events earthquakes at the outer rise within the subducting slab or overlying crust intraplate events and tsunami earthquakes that generate considerably larger tsunamis than expected from seismic waves the depth range of a typical interplate earthquake source is 10 40km controlled by temperature and other geological parameters the slip distribution varies both with depth and along strike recent examples show very different temporal change of slip distribution in the aleutians and the japan trench the tsunamigenic coseismic slip of the 1957 aleutian earthquake was concentrated on an asperity located in the western half of an aftershock zone 1200km long this asperity ruptured again in the 1986 andreanof islands and 1996 delarof islands earthquakes by contrast the source of the 1994 sanriku oki earthquake corresponds to the low slip region of the previous interplate event the 1968 tokachi oki earthquake tsunamis from intraplate earthquakes within the subducting slab can be at least as large as those from interplate earthquakes tsunami hazard assessments must include such events similarity in macroseismic data from two southern kuril earthquakes illustrates difficulty in distinguishing interplate and slab events on the basis of historical data such as felt reports and tsunami heights most moment release of tsunami earthquakes occurs in a narrow region near the trench and the concentrated slip is responsible for the large tsunami numerical modeling of the 1996 peru earthquake confirms this model which has been proposed for other tsunami earthquakes including 1896 sanriku 1946 aleutian and 1992 nicaragua

numerical modelling of tsunami generation and propagation from submarine slumps the 1998 papua new guinea event summary deep and large submarine slumps may generate tsunamis as disastrous as tsunamis of tectonic origin such a landslide is likely to be the origin of the 1998 july 17 tsunami of papua new guinea the deadliest tsunami in the last 50 years water waves devastated a 20 km stretch of coastline wiping out three villages and killing more than 2200 people a numerical model has been developed to study the efficiency of deep slumps in producing tsunamis and has been applied to the papua new guinea event the landslide is treated as the flow of a homogeneous gravity driven continuum governed by a rheological law water waves are generated by sea bottom displacements induced by the landslide the shallow water approximation is adopted for both the landslide and the associated water waves the resulting differential equations are solved by a finite difference method based on shock capturing the shallow water hypothesis is tested by comparison with a model solving navier stokes equations for a mixture of water and sediments sensitivity tests carried out for a 2 d simplified geometry show that the water surface profile depends strongly on the constitutive law of the landslide the 1998 event is simulated numerically by the shallow water model testing different friction laws the observed inundation height distribution is well reproduced by the model for a volume of 4 km3 with its top located at a water depth of 550 m and sliding with a coulomb type friction law over a distance of 5 km

a methodology for near field tsunami inundation forecasting application to the 2011 tohoku tsunami existing tsunami early warning systems in the world can give either one or a combination of estimated tsunami arrival times heights or qualitative tsunami forecasts before the tsunami hits near field coastlines a future tsunami early warning system should be able to provide a reliable near field tsunami inundation forecast on high resolution topography within a short time period here we describe a new methodology for near field tsunami inundation forecasting in this method a precomputed tsunami inundation and precomputed tsunami waveform database is required after information about a tsunami source is estimated tsunami waveforms at nearshore points can be simulated in real time a scenario that gives the most similar tsunami waveforms is selected as the site specific best scenario and the tsunami inundation from that scenario is selected as the tsunami inundation forecast to test the algorithm tsunami inundation along the sanriku coast is forecasted by using source models for the 2011 tohoku earthquake estimated from gps w phase or offshore tsunami waveform data the forecasting algorithm is capable of providing a tsunami inundation forecast that is similar to that obtained by numerical forward modeling but with remarkably smaller cpu time the time required to forecast tsunami inundation in coastal sites from the sendai plain to miyako city is approximately 3 min after information about the tsunami source is obtained we found that the tsunami inundation forecasts from the 5 min gps 5 min w phase 10 min w phase fault models and 35 min tsunami source model are all reliable for tsunami early warning purposes and quantitatively match the observations well although the latter model gives tsunami forecasts with highest overall accuracy the required times to obtain tsunami forecast from the above four models are 8 min 9 min 14 min and 39 min after the earthquake respectively or in other words 3 min after receiving the source model this method can be useful in developing future tsunami forecasting systems with a capability of providing tsunami inundation forecasts for locations near the tsunami source area

intensified oceanic circulation during early carboniferous cooling events evidence from carbon and nitrogen isotopes abstract the early carboniferous was a climatic transition interval from a mid paleozoic greenhouse world into the late paleozoic ice age it was marked by a long term cooling trend that was punctuated by short glaciations in the tournaisian and visean early to mid early carboniferous here we generated organic carbon and nitrogen isotope profiles for two widely separated lower carboniferous sections arrow canyon range nevada and namur dinant basin belgium in order to assess the global nature and timing of changes in the carbon nitrogen cycles linked to oceanic productivity and redox conditions during this climatic transition interval the carbon and nitrogen isotope profiles of both study sections record major perturbations during the mid tournaisian and visean a mid tournaisian event tice is marked by increases in 13ccarb 13corg and 15nbulk at arrow canyon from 0 6 to 7 0 25 2 to 23 7 and 0 6 to 8 9 respectively and namur dinant from 0 3 to 4 7 27 9 to 22 2 and 5 7 to 5 2 respectively an early visean event vice named herein is marked by increases in 13ccarb 13corg and 15nbulk at arrow canyon from 0 6 to 3 1 28 4 to 23 6 and 1 4 to 9 4 respectively and namur dinant from 2 1 to 4 3 26 7 to 25 0 and 1 4 to 3 3 respectively the positive excursions in all three isotopic records during these events are consistent with increased fractional burial of organic carbon and enhanced denitrification implying intensification of marine productivity and expansion of hypoxia in the global ocean given that each event coincided with lowering of sea surface temperatures and increased glaciation as documented from published conodont 18o and sea level records we hypothesize that global cooling led to intensified oceanic circulation and upwelling on continental margins triggering increased marine productivity and attendant redox changes within the affected upwelling zones our results provide new insights into changes in early carboniferous oceanic conditions in response to the initial stages of cooling leading into the late paleozoic ice age

towards an understanding of the ca isotopic signal related to ocean acidification and alkalinity overshoots in the rock record abstract in this contribution we explore the idea that the ca isotope proxy has utility as an indicator of carbonate authigenesis i e post depositional precipitation of caco3 within the sedimentary package given the strong contrast in isotopic fractionation factor between the formational and diagenetic environments ca isotopes have the potential to fingerprint carbonate authigenesis when it occurs close to the seawater sediment interface we demonstrate that ca isotopes are particularly applicable to exploring ocean acidification events and potentially ocean anoxic events and focus our attention on ocean acidification related to the paleocene eocene thermal maximum petm we present three scenarios that vary in the magnitude and duration of the carbon fluxes that are simulated using an earth system model of intermediate complexity cgenie and we use the cgenie output to constrain the upper boundary conditions of 1 d reactive transport models of authigenesis and recrystallization in the sedimentary section along with simple mixing calculations the models inform our exploration of the hypothesis that authigenic carbonate induced by a saturation state overshoot during the petm explains recently published ca isotope records and perhaps bulk carbonate records over ocean anoxic event oae 2 our simulations suggest that fractionation factor variability does not explain the petm 44ca records and we propose a 44ca caco3 space framework to assist with the elucidation of authigenic additions over time scales that are short relative to the residence time of ca in the ocean 1 ma ultimately we find that the authigenic zone generated in the sedimentary column may be influenced by alkalinity overshoots or redox state the caco3 produced in this zone can overprint temporal signals with depth dependent signals that reflect lithology and sedimentation rate and need not be spatially uniform even when driven by a global event ultimately we demonstrate the utility of ca isotopes for exploring short time scale climatic events and a quantitative framework to guide interpretations

glacioeustasy meteoric diagenesis and the carbon cycle during the middle carboniferous middle carboniferous carbonates in the western u s have undergone pleistocene bahamas style meteoric diagenesis that may be associated with expanding late paleozoic ice sheets fourteen stratigraphic sections from carbonate platforms illustrate the regional distribution and variable intensity of physical and chemical diagenesis just below the middle carboniferous unconformity these sections contain top negative carbon isotope excursions that terminate in regional exposure surfaces that are associated with some combination of karst towers desiccation cracks fabric destructive recrystallization or extensive root systems the timing of the diagenesis is synchronous with similarly scaled top negative carbon isotope excursions observed by others in england kazakhstan and china the mass flux of negative carbon required to generate similar isotopic profiles across the areal extent of middle carboniferous platform carbonates is a significant component of the global carbon cycle we present a simple carbon box model to illustrate that the 13c of dissolved inorganic carbon in the ocean could be elevated by 1 4 as isotopically light carbon from the weathering of terrestrial organic matter reacts with exposed platforms before reaching the ocean and atmosphere these results represent an improvement on global biogeochemical models that have struggled to provide a congruent solution to the high 13c of the late paleozoic icehouse

linear and nonlinear computations of the 1992 nicaragua earthquake tsunami numerical computations of tsunamis are made for the 1992 nicaragua earthquake using different governing equations bottom frictional values and bathymetry data the results are compared with each other as well as with the observations both tide gauge records and runup heights comparison of the observed and computed tsunami waveforms indicates that the use of detailed bathymetry data with a small grid size is more effective than to include nonlinear terms in tsunami computation linear computation overestimates the amplitude for the later phase than the first arrival particularly when the amplitude becomes large the computed amplitudes along the coast from nonlinear computation are much smaller than the observed tsunami runup heights the average ratio or the amplification factor is estimated to be 3 in the present case when the grid size of 1 minute is used the factor however may depend on the grid size for the computation

the role of the global carbonate cycle in the regulation and evolution of the earth system we review one of the most ancient of all the global biogeochemical cycles and one which reflects the profound geochemical and biological changes that have occurred as the earth system has evolved through time that of calcium carbonate caco3 in particular we highlight a mid mesozoic revolution in the nature and location of carbonate deposition in the marine environment driven by the ecological success of calcareous plankton this drove the creation of a responsive deep sea sedimentary sink of caco3 the result is that biologically driven carbonate deposition provides a significant buffering of ocean chemistry and of atmospheric co2 in the modern system however the same calcifying organisms that under pin the deep sea carbonate sink are now threatened by the continued atmospheric release of fossil fuel co2 and increasing acidity of the surface ocean we are not yet in a position to predict what the impact on caco3 production will be or how the uptake of fossil fuel co2 by the ocean will be affected this uncertainty in the future trajectory of atmospheric co2 that comes from incomplete understanding of the marine carbonate cycle is cause for concern

the 1998 papua new guinea earthquake and its fault plane estimated from relocated aftershocks the 1998 papua new guinea earthquake of m w 7 0 occurred near the wewak trench where the north bismarck plate is subducting beneath the australian plate its mechanism is thrust type and one of the nodal planes is almost parallel to the plate interface to determine which of the two nodal planes of the main shock is the fault plane we relocated the main shock and aftershocks using a method of modified joint hypocenter determination we combined and employed two types of data in this study firstly we used data reported by the national earthquake information center neic of the u s geological survey usgs which includes three stations at the northeastern edge of irian jaya and one station in northern papua new guinea from which the epicentral distances are less than 2 degrees secondly in addition to the above permanent station data we used data from temporary aftershock observations near the epicentral area around the sissano lagoon carried out by tsuji et al 1998 using three component seismometers they carried out observations from august 2 to october 2 1998 at three sites although the network did not record the main shock and immediate aftershocks the data obtained by temporary observation sites can clearly assist in identifying their absolute locations since it is possible to apply the joint hypocenter determination jhd method hypocenters were relocated between the coastline and the wewak trench distributed along a nodal plane dipping shallowly to the southwest therefore we can conclude that this nodal plane is the main shock fault and that the 1998 papua new guinea earthquake was an interplate earthquake between the north bismarck and australian plates

modeling the effects of diagenesis on carbonate clumped isotope values in deep and shallow water settings the measurement of multiply isotopically substituted clumped isotope carbonate groups provides a way to reconstruct past mineral formation temperatures however dissolution reprecipitation i e recrystallization reactions which commonly occur during sedimentary burial can alter a sample s clumped isotope composition such that it partially or wholly reflects deeper burial temperatures here we derive a quantitative model of diagenesis to explore how diagenesis alters carbonate clumped isotope values we apply the model to a new dataset from deep sea sediments taken from ocean drilling project site 807 in the equatorial pacific this dataset is used to ground truth the model we demonstrate that the use of the model with accompanying carbonate clumped isotope and carbonate 18 o values provides new constraints on both the diagenetic history of deep sea settings as well as past equatorial sea surface temperatures specifically the combination of the diagenetic model and data support previous work that indicates equatorial sea surface temperatures were warmer in the paleogene as compared to today we then explore whether the model is applicable to shallow water settings commonly preserved in the rock record using a previously published dataset from the bahamas we demonstrate that the model captures the main trends of the data as a function of burial depth and thus appears applicable to a range of depositional settings

abnormal tsunamis caused by the june 13 1984 torishima japan earthquake an earthquake with an m s 5 6 m b 5 5 which occurred near torishima japan on june 13 1984 generated abnormally large tsunamis tsunami magnitude m t 7 3 for its relatively small earthquake magnitude the maximum amplitude of the tsunamis is not a simple function of distance as the magnitude formula implies in order to quantify the abnormal tsunamis we modeled the tsunami source using a finite difference computation on the actual bathymetry the source of these abnormal tsunamis is modeled as a water surface displacement with a radius of 12 km and maximum water height of 13 cm the displaced water volume is 4 10 13 cm 3 and the potential energy is calculated as 2 10 17 ergs if this water displacement is due to a fault motion at 5 km depth a moment magnitude m w is estimated to be 6 3 this value is larger than m w estimated from seismic waves by 0 7 but smaller than m t by 1 0 the former difference suggests that the earthquake source is very different from an ordinary faulting if we assume the source is a horizontally lying tensile crack at shallow depth about 2 km that explains both the water surface displacement and the seismic moment tensor the tensile crack is interpreted as an injection of material as suggested by a seismological study the discrepancy between m w and m t indicates that the propagation path is responsible for the observed large tsunamis the numerical computation shows a focusing of energy during the propagation of the tsunami along the shallow izu bonin ridge system thus the abnormally large tsunamis from the torishima earthquake are a result of both source and path effects

response of dissolved inorganic carbon dic and δ13cdic to changes in climate and land cover in sw china karst catchments abstract monthly hydrochemical data and 13c of dissolved inorganic carbon dic in karst water samples from september 2007 to october 2012 were obtained to reveal the controlling mechanisms on dic geochemistry and 13cdic under different conditions of climate and land cover in three karst catchments banzhai dengzhanhe and chenqi in guizhou province sw china dic of karst water at the banzhai site comes mainly from carbonate dissolution under open system conditions with soil co2 produced by root respiration and organic carbon decomposition with lowest 13c values under its dense virgin forest coverage weaker carbonate bedrock dissolution due to sparse and thin soil cover results in lower 13cdic pco2 dic and ec and lower cation and anion concentrations at the chenqi site larger soil co2 input from a thick layer of soil results in high pco2 and dic and low ph sic and 13cdic in the karst water at the dengzhanhe site a lesser soil co2 input due to stronger karst rock desertification and strong gypsum dissolution contribute to higher 13cdic high ec and high cation and anion concentrations soil co2 inputs controlled by biological activity and available soil moisture carbonate bedrock dissolution dilution and degassing effects vary seasonally following rainfall and temperature changes consequently there are seasonal cycles in hydrochemistry and 13cdic of the karst water with high pco2 and low ph ec sic and 13cdic values in the warm and rainy seasons and vice versa during the cold and dry seasons a strongly positive shift 3 in 13cdic occurred in the drought year 2011 indicating that 13cdic in groundwater systems can be an effective indicator of environmental and or climate changes

simulating meteoric and mixing zone carbonate diagenesis with a two dimensional reactive transport model meteoric and mixing zone diagenesis can dramatically alter the geochemical signatures of shallow marine carbonates most preserved pre cretaceous carbonates were deposited in shallow marine environments and thus may have been susceptible to meteoric and mixing zone diagenesis however a quantitative understanding of how the geochemical composition of carbonates changes during diagenesis still requires further development here we present a new two dimensional 2d reactive transport model coupled with a 2d coastal hydrology model to simulate carbonate diagenesis and provide insights into its impact on the isotopic and elemental compositions of carbonates in the geological record using this model we have simulated the stratigraphic trends and relationship between isotopic records for example 13c and 18o values observed in modern recent miocene sections where the impact of meteoric diagenesis has been clearly characterized our model can also reproduce anomalous neoproterozoic carbonate geochemical profiles where the effects of meteoric diagenesis have been debated further our model indicates that linear carbonate c o isotope co variations can either be generated in the mixing zone between freshwater and marine pore waters or in the freshwater phreatic zone with a downward decrease in recrystallization with no net carbonate dissolution or precipitation rate in addition numerous processes were observed to decouple 18ocarb values from other isotopic and elemental signatures during carbonate diagenesis indicating that a lack of linear correlation between 18ocarb values and other geochemical variables does not necessarily suggest limited meteoric alteration sensitivity analyses show that the steady state timescale is controlled by compositional differences between fluid endmembers the calcite water element distribution coefficient the recrystallization rate porosity and the groundwater discharge rate given that reactive transport models have proven to be powerful theoretical tools in many disciplines of earth sciences our hope is that this model will promote a more quantitative understanding of meteoric and mixing zone diagenesis of marine carbonates

geochemistry of meteoric diagenesis in carbonate islands of the northern bahamas 1 evidence from field studies processes driving carbonate diagenesis in islands of the northern bahamas are investigated using major ion dissolved oxygen and dissolved organic carbon analyses of water samples from surface and ground waters and measurements of soil gas pco2 meteoric waters equilibrate with aragonite but reactions are water controlled rather than mineral controlled and drive dissolution rather than concurrent precipitation of calcite surface runoff waters equilibrate with atmospheric pco2 and rapidly recharge the vadose zone limiting subaerial bedrock dissolution to only 6 6 15 mg l 1 ca pco2 of soil gas measured in the summer wet season 7 4 s 3 7 10 3 atm is elevated compared with that of the atmosphere despite the thin skeletal organic nature of the soil and the discontinuous soil cover soil waters retained in surface pockets are equilibrated with respect to aragonite and have dissolved 51 s 19 mg l 1 ca this is substantially less than the 93 s 18 mg l 1 ca in samples from pumping boreholes that sample meteoric waters from the freshwater lens the high pco2 of the freshwater lens 16 s 8 3 10 3 atm for pumping boreholes suggests that significant additional co2 may be derived by oxidation of soil and surface derived organic carbon within the lens the suboxic nature of the majority of the freshwater lens and the observed depletion in sulphate support this suggestion and indicate that both aerobic and anaerobic oxidation may take place shallow lens samples from observation boreholes are calcite supersaturated and have a lower pco2 than deeper lens waters indicating that co2 degasses from the water table driving precipitation of calcite cements we suggest that the geochemical evolution of waters in the vadose zone and upper part of the freshwater lens may be determined by the presence of a body of ground air with pco2 controlled by production in the freshwater lens and soil and by degassing to the atmosphere copyright 2007 john wiley sons ltd

a decade of horizontal deformation from great earthquakes 1 the 21st century has seen the occurrence of 17 great earthquakes mw 8 including some of the largest earthquakes ever recorded numerical modeling of the earthquakes shows that nearly half of the earth s surface has undergone horizontal coseismic deformation 1 mm with the 2004 sumatra andaman earthquake dominating the global deformation field this has important implications for both the realization of a terrestrial reference frame and in the interpretation of regional tectonic studies based on gps velocities we show that far field coseismic deformations from great earthquakes will if unaccounted for introduce errors in estimates of linear site velocities of at least 0 1 0 3 mm yr across most of the surface of the earth the accumulated global deformation field shows that two regions australia and the north atlantic arctic ocean have been largely undeformed by these great earthquakes with accumulated deformations generally 0 5 mm using gps estimates of surface deformation we show that the majority of the australian continent is deforming at 0 2 mm yr the northern part of new zealand is rotating clockwise relative to the australian plate with relative horizontal velocities of 2 mm yr while the southeastern coast of australia is undergoing post seismic relaxation caused by the 2004 mw 8 1 macquarie ridge earthquake the presence of ongoing post seismic relaxation thousands of kilometers from plate margins violates the secular linear assumption made in current terrestrial reference frame definitions these effects have significant ramifications for regional tectonic interpretations and global studies such as sea level rise that require reference frame accuracy greater than this level

continental drift and phanerozoic carbonate accumulation in shallow shelf and deep marine settings knowledge of past rates of transfer of rock forming materials among the principal geologic reservoirs is central to understanding causes and magnitudes of change in earth surface processes over phanerozoic time to determine typical rates of global sediment cycling we compiled information on area volume and lithology of shallow water sediments by epoch for both terrigenous clastics and marine carbonates data on amounts of surviving continental terrigenous rock as opposed to deep oceanic and including terrestrial marginal marine and marine deposits exhibit positive age area trends wherein greatest areas and volumes of conglomerate sandstone and shale are represented by younger sequences global volumes of terrigenous clastic sediment yield a mean cycling rate of 0 00124 m yr similar to that determined for eurasian 0 00127 north american 0 00058 a b ronov 0 00352 t d cook and a w bally african 0 0017 and south american 0 0021 clastic sequences surficial erosion results in the mean destruction of 0 124 of terrigenous rock volume per million years of reservoir age in contrast surviving epicratonic and shelf margin carbonate sequences yield negative cycling rates of about 0 164 m yr surviving areas and volumes increase with sequence age that is the amount of limestone and dolostone preserved in shallow water settings increases back in time to maximal areal extents in the middle and upper cambrian mass age data on terrigenous clastic successions indicate generally constant rates of crustal erosion over phanerozoic time decrease in size of the shallow marine carbonate reservoir forward in time therefore suggests generally invariant rates of global limestone accumulation and a shift in sites of accumulation from shallow cratonic to deep oceanic settings over much of the past 540 m yr causes of this eon scale depositional translocation of carbonate sediment from shallowto deep marine settings cannot be satisfactorily linked to either changes in global sea level or the evolution of carbonate producing plankton because neither exhibits a pattern of unidirectional change in position or abundance since the early phanerozoic however tabulation of long term variation in areas of continental shelves from paleogeographic maps reveals a generally uniform decrease in low latitude 30 platform area with decreasing age over most of the phanerozoic moreover rate of change of low latitude shelf area km 2 m yr is almost exactly

the effect of bathymetry on tsunami characteristics at sisano lagoon papua new guinea the 1998 papua new guinea tsunami was greater than expected from its earthquake magnitude the area of significant impact was small approximately a 30 km stretch near the mouth of sissano lagoon papua new guinea to explain the localized nature of the event a submarine landslide has been conjectured to be responsible our study indicates that offshore bathymetry is critical to predicting tsunami coastal behavior model runs with newly obtained bathymetric data indicate that an earthquake fault source combined with the existing seafloor geometry may also explain the concentrated tsunami although the definitive cause of the papua new guinea tsunami remains uncertain local bathymetry had a notable effect on the wave behavior

source of high tsunamis along the southernmost ryukyu trench inferred from tsunami stratigraphy abstract four paleotsunamis deposits are exposed in a trench on the coastal lowland north of the southern ryukyu subduction zone trench radiocarbon ages on coral and bivalve shells show that the four deposits record tsunamis date from the last 2000 yrs including a historical tsunami with a maximum run up of 30 m in 1771 for an average recurrence interval of approximately 600 yrs ground fissures in a soil beneath the 1771 tsunami deposit may have been generated by stronger shaking than recorded by historical documents the repeated occurrence of the paleotsunami deposits supports a tectonic source model on the plate boundary rather than a nontectonic source model such as submarine landslides assuming a thrust model at the subduction zone the seismic coupling ratio may be as low as 20

isotope signatures associated with early meteoric diagenesis the environments in which carbonate diagenesis proceeds have been documented in previous studies of holocene and late pleistocene sediments and limestones on barbados west indies variations in the carbon and oxygen isotopic composition of limestones produced during early freshwater diagenesis have been observed in this study to occur in specific patterns six potentially useful patterns emerge when one views stable isotope data within a stratigraphic framework 1 the subaerial exposure surface is characterized by strongly 12c enriched limestones 13c compositions of underlying limestones grow progressively heavier with increasing depth 2 the subaerial exposure surface may also be marked by slight 18o enrichment 3 an abrupt shift in 18o values may differentiate sediments above the exposure surface from those below 4 sediments altered in the marine meteoric mixing zone may be characterized by positive covariance between their 18o and 13c compositions 5 the vadose phreatic boundary may be marked by a sharp increase in 13c values in the seaward portions of a fresh groundwater system and 6 samples contemporaneously altered in a single fresh groundwater system within an areally restricted region should display a narrow range of 18o and a wide range of 13c compositions analysis of samples from five palaeozoic and mesozoic formations which contained petrographic evidence of early freshwater diagenesis showed that isotope patterns similar to those observed in barbados limestones have been preserved in rocks as old as mississippian these isotope patterns could prove to be useful for identifying diagenetically induced porosity trends in carbonate rocks they might be used to identify limestones diagenetically altered in meteoric environments to identify mixing zone cements and dolomites and to trace the regional and vertical distributions of early meteoric groundwater systems in ancient carbonate formations

the nature of the δ13c of periplatform sediments implications for stratigraphy and the global carbon cycle the carbon isotopic composition y 13 c of bulk carbonates obtained from a transect of sites drilled through platform and periplatform sediments of holocene to early miocene age has been compared to ascertain whether changes in the y 13 c can be correlated between sediments of equivalent ages and whether such changes can be related to global changes in the y 13 c of the dissolved inorganic carbon in the oceans over this time period five of the sites were drilled during leg 166 of the ocean drilling project 1003 1007 in a transect ranging from five km to 25 km away from the platform margin and penetrating sediments of holocene to oligocene age that are contained in 17 depositional sequences a q two shallow water sites clino and unda were situated on a extension of the same transect on great bahama bank in a water depth of 10 15 m with the exception of unda and clino the y 13 c of the carbonates ranges from 5x in the younger sequences to 1x in the early miocene in each of the sites the y 13 c is strongly positively correlated with the percentage of aragonite as a consequence the y 13 c of sequences a through f is strongly correlated reflecting the decreasing amount of aragonite with increasing depth in the two platform sites the y 13 c is significantly lower in the younger portions of the cores as a result of the influences of meteoric diagenesis during repeated exposure during the pleistocene although the y 13 c of the individual sequences can be correlated in most instances between the odp holes the changes are not related to global changes in the y 13 c of the oceans which in contrast to the y 13 c of the platform sediments become isotopically lower towards the present day instead variations in the y 13 c appear to be related to varying mixtures of y 13 c rich banktop sediments and pelagic material

analysis of the far field tsunamis generated by the 1998 papua new guinea earthquake the tsunami generated by the 1998 papua new guinea earthquake was observed at several tide gauges and ocean bottom pressure gauges in japan the fault model of the 1998 papua new guinea earthquake was estimated using those tsunami waveforms observed in japan and coseismic subsidence observed along the coast of papua new guinea near the source region the numerical simulation of the tsunami using the linear boussinesq equation was carried out the tsunami waveforms in japan are explained by the fault model which is consistent with the harvard cmt solution including the seismic moment of 3 7 1019 nm the additional tsunami source such as a sediment slump is not needed to explain the observed tsunami in japan the mechanism of the earthquake was likely to be a steeply dipping reverse fault the 1998 papua new guinea earthquake was likely to occur within a small accretionary prism near the new guinea trench

the july 1998 papua new guinea earthquake mechanism and quantification of unusual tsunami generation the unusual tsunami generated by the july 17 1998 papua new guinea earthquake was investigated on the basis of various geophysical observations including seismological data tsunami waveform records and on land and submarine surveys the tsunami source models were constructed for seismological high angle and low angle faults splay fault and submarine slumps far field and near field tsunamis computed from these models were compared with the recorded waveforms in and around japan and the measured heights along the coast around sissano lagoon respectively in order to reproduce the far field tsunami waveforms small sources such as splay fault or submarine slump alone were not enough and a seismological fault model was required relocated aftershock distribution and observed coastal subsidence were preferable for the low angle fault but the low angle fault alone could not reproduce the large near field tsunamis the low angle fault with additional source possibly a submarine slump is the most likely source of the 1998 tsunami although other possibilities cannot be excluded computations from different source models showed that the far field tsunami amplitudes are proportional to the displaced water volume at the source and the comparison with the observed tsunami amplitudes indicated that the displaced water volume at the 1998 tsunami source was 0 6 km3 the near filed tsunami heights on the other hand are determined by the potential energy of displaced water and the comparison with the observed heights showed that the potential energy was 2 x 1012 j

estimation of current plate motions in papua new guinea from global positioning system observations plate tectonic motions have been estimated in papua new guinea from a 20 station network of global positioning system sites that has been observed over five campaigns from 1990 to 1996 the present velocities of the sites are consistent with geological models in which the south bismarck woodlark and solomon sea plates form the principal tectonic elements between the pacific and australian plates in this region active spreading is observed on the woodlark basin spreading centre but at a rate that is about half the rate determined from magnetic reversals the other major motions observed are subduction on the new britain trench seafloor spreading across the bismarck sea seismic lineation convergence across the ramu markham fault and left lateral strike slip across the papuan peninsula these motions are consistent with a 8 2 myr 1 clockwise rotation of the south bismarck plate about a pole in the huon gulf and a rotation of the woodlark plate away from the australian plate second order deformation may also be occurring in particular manus island and northern new ireland may be moving northward relative to the pacific plate at 5 8 mm yr 1 significant at the 95 but not at the 99 confidence level which may suggest the existence of a north bismarck plate

revealing the source of the 27 august 1810 loreto baja california tsunami from historical evidence and numerical modelling historical documents revealed that on 27 august 1810 an earthquake affected the loreto town and the surrounding region along 200 km of the coast of baja california mexico and damage was considerable due to strong ground motions however the 1810 loreto earthquake unlike other earthquakes of the nineteenth and twentieth centuries produced an extensive tsunami flooding on the eastern coast of baja california from loreto to la paz we report here the historical account of this event and analyse the source of the related tsunami based on the historical record and the tectonic setting we infer that this earthquake was produced along a transform fault right lateral strike slip fault farallon fault on the baja california gulf however the associated tsunami was disproportionally large if compared with the earthquake intensity ix and approximate magnitude 7 4 mw fault style and the relatively late tsunami arrival i e an hour after the earthquake suggesting that a submarine landslide triggered by this earthquake was the suspect source for the loreto tsunami we present here historical data and a numerical model of the loreto 1810 tsunami to elucidate the source using both the 1810 earthquake and a submarine landslide and confirm that a submarine landslide is most likely the tsunami triggering mechanism that followed the 1810 earthquake

a probabilistic analysis of meteorically altered δ13c chemostratigraphy from late paleozoic ice age carbonate platforms the stratigraphic expression of meteoric diagenesis in carbonates is a glimpse into the weathering fluid transport and biological productivity of the ancient near surface terrestrial environment to infer this environmental information we use a probabilistic approach to merge an isotope based reactive transport model with chemostratigraphic data from carbonates that were subaerially exposed during an expansion of the late paleozoic ice age in the middle carboniferous the rate of carbon flowing through the carbonate platform relative to the rate of carbon reacting between mineral and fluid phases controls the length scale curvature and magnitude of the diagenetic carbon isotope profiles the ratio of advection to reaction is determined for seven stratigraphic sections and the advection rate is used to estimate the minimum carbonate weathering associated with each profile these carbonate weathering rates extrapolated over the expansive shallow carbonate platforms of the middle carboniferous indicate that glacioeustatic fall may have caused a 20 50 increase in the dissolved caco3 flux to the ocean the complex feedbacks among carbonate weathering and accumulation atmospheric p co2 glacioeustasy and passive margin subsidence may have played an unexplored role in the glacial interglacial climate dynamics of the late paleozoic ice age

the 17 july 1998 tsunami papua new guinea evidence and initial interpretation abstract a m w 7 1 earthquake that occurred at 08 49 hours 17 july 1998 utc 6 49 pm local time off the north coast of papua new guinea generated a locally destructive tsunami more than 2189 people died and virtually no structures were left standing along 19 km of coast a fast moving wall of sand laden water left fishing nets and other detritus in trees up to 17 5 m above sea level concrete was stripped to the reinforcing metal and some trees were ripped out and carried more than a kilometre back into sissano lagoon the site is in an active sedimentary basin the aitape trough with 4500 m thickness of neogene sediments between the bewani fault zone and the wewak trench there is some debate about the form of tsunami propagation for this event however we present evidence for subsidence of 30 40 cm on the landward side of the spit fronting sissano lagoon furthermore the area may have subsided up to three times this century in situ stumps of drowned trees in the lagoon record at least one earlier event the low angle harvard university cmt solution m w 7 1 depth 6 0 km 10 landward dip on fault with northward displacement is consistent with the tectonic setting and pattern of aftershocks elastic modelling of the energy release suggests 2 m horizontal displacement over 600 km 2 40 cm subsidence landward and 60 cm uplift seaward convergent flow of the displaced water into the area of subsidence focused wave energy on the coast and generated the locally high wave the record of tsunami at sissano lagoon indicates that the spit fronting the lagoon is unsafe for habitation there is potential for similar coseismic coastal subsidence to focus tsunami in other areas with similar tectonic settings

new insights into the source of the makran tsunami of 27 november 1945 from tsunami waveforms and coastal deformation data we constrain the source of the 27 november 1945 tsunami in the makran subduction zone msz using available tsunami waveforms recorded on tide gauges at mumbai india and karachi pakistan and that inferred at port victoria seychelles and coseismic deformation data along the makran coast spectral analysis of the tsunami waveforms shows that the tsunami governing period was 40 50 min at karachi whereas it was around 22 min at mumbai the inferred tsunami waveform at port victoria also indicated a period of around 21 min for the tsunami tsunami numerical simulations from the previously proposed source models failed in reproducing the observed tsunami waveforms and coseismic deformation data sensitivity analysis showed that the source fault needs to be extended offshore into deep water in order to reproduce the first 22 min signal at mumbai based on the inversion of the observed tsunami waveforms we propose a four segment fault with varying slip amounts as the final source this source includes a slip of 4 3 m onshore near ormara pakistan and a slip of 10 m offshore at water depth of around 3 000 m the total fault length is 220 km and the average slip is 6 1 m this source first reproduces fairly well the observed tide gauge records at mumbai and karachi second produces 1 m of uplift at ormara and 1 m of subsidence at pasni and third gives a moment magnitude of 8 3 for the earthquake which is in the acceptable range of seismic data the computed 1 m uplift at ormara is in the uplift range of 1 3 m reported in the literature as the tide gauge stations were located in the far field our proposed source explains mainly the tectonic source of the tsunami

global deep sea burial rate of calcium carbonate during the last glacial maximum global databases concentrations rates in holocene and last glacial of calcium carbonate and mass accumulation maximum sediments were used to estimate the deep sea sedimentary calcium carbonate burial rate during these two time intervals sparse calcite mass accumulation rate data were extrapolated across regions of varying calcium carbonate concentration using a gridded map of calcium carbonate concentrations and the assumption that accumulation of noncarbonate material is uncorrelated with calcite concentration within some geographical region mean noncarbonate accumulation rates were estimated within each of nine regions determined by the distribution and nature of the accumulation rate data for core top sediments data coverage 67 of the high calcite the regions of reasonable encompass 75 sediments globally and within these regions we estimate an accumulation rate of 55 9 3 6x1011 mol yr 1 the same regions cover 48 of glacial high caco3 sediments the smaller fraction is due to a shift of calcite deposition to the poorly sampled south pacific and total 44 1 6 0x1011 mol yr 1 projecting to 100 coverage south and total 44 1 6 0x1011 both estimates yields accumulation estimates of 8 3x1012 mol yr 1 today and 9 2x1012 mol yr 1 during glacial time this is little better than a guess given the incomplete data coverage but it suggests that glacial deep sea calcite burial rate was probably not considerably faster than today in spite of a presumed decreasein shallow water burial during glacial time

near field modeling of the july 17 1998 tsunami in papua new guinea modest earthquakes may trigger large submarine landslides responsible for disastrous tsunami waves as demonstrated by the papua new guinea event of july 17 1998 the relatively small earthquake was followed by unexpectedly high waves up to 15 m wiping out 3 villages and killing more than 2200 people numerical simulations show that seismic dislocation sources are not energetic enough to reproduce the observed tsunami along the coast tsunami generation by a submarine landslide has been simulated by a finite difference model assimilating the landslide to a flow of granular material long wave approximation is adopted for both water waves and the slide numerical results show that observed inundation heights are well reproduced for a volume of 4 km located 20 km offshore sliding downslope with a coulomb type friction

direct energy estimation of the 2011 japan tsunami using deep ocean pressure measurements 1 we have developed a method to compute the total energy transmitted by tsunami waves to the case where the earthquake source is unknown by using deep ocean pressure measurements and numerical models tsunami source functions based on the first wave recorded at the two closest tsunameters deep ocean assessment and reporting of tsunamis dart our analysis suggests that the march 11 2011 tohoku oki tsunami generated off japan originated from a 300 400 km long and 100 km wide area and the total propagated energy is 3 1015j with 6 uncertainty measurements from 30 tsunameters and 32 coastal tide stations show excellent agreement with the forecasts obtained in real time our study indicates that the propagated energy and the source location are the most important source characteristics for predicting tsunami impacts interactions of tsunami waves with seafloor topography delay and redirect the energy flux posing hazards from delayed and amplified waves with long duration seafloor topography also gives its spectral imprint to tsunami waves travel time forecast errors are path specific and correlated to the major wave scatterers in the pacific numerical dissipation in the propagation modeling highlights the need of high resolution inundation models for accurate coastal predictions on the other hand it also can be used to account for physical dissipation to achieve efficiency our results provide guidelines for the earliest reliable tsunami forecast warnings of long duration tsunami waves signals and enhancement of the experimental tsunami forecast system we apply the method to quantify the energy of 15 past tsunamis independently from earthquake magnitudes the small tsunami to seismic radiation energy ratios and their variability 0 01 0 8 reinforce the importance of using deep ocean tsunami data the direct measures of tsunamis for estimates of tsunami energy and accurate forecasting

fault slip distribution of the 2016 fukushima earthquake estimated from tsunami waveforms the 2016 fukushima normal faulting earthquake mjma 7 4 occurred 40 km off the coast of fukushima within the upper crust the earthquake generated a moderate tsunami which was recorded by coastal tide gauges and offshore pressure gauges first the sensitivity of tsunami waveforms to fault dimensions and depths was examined and the best size and depth were determined tsunami waveforms computed based on four available focal mechanisms showed that a simple fault striking northeast southwest and dipping southeast strike 45 dip 41 rake 95 yielded the best fit to the observed waveforms this fault geometry was then used in a tsunami waveform inversion to estimate the fault slip distribution a large slip of 3 5 m was located near the surface and the major slip region covered an area of 20 km 20 km the seismic moment calculated assuming a rigidity of 2 7 1010 n m2 was 3 70 1019 nm equivalent to mw 7 0 this is slightly larger than the moments from the moment tensor solutions mw 6 9 large secondary tsunami peaks arrived approximately an hour after clear initial peaks were recorded by the offshore pressure gauges and the sendai and ofunato tide gauges our tsunami propagation model suggests that the large secondary tsunami signals were from tsunami waves reflected off the fukushima coast a rather large tsunami amplitude of 75 cm at kuji about 300 km north of the source was comparable to those recorded at stations located much closer to the epicenter such as soma and onahama tsunami simulations and ray tracing for both real and artificial bathymetry indicate that a significant portion of the tsunami wave was refracted to the coast located around kuji and miyako due to bathymetry effects