calcic amphibole equilibria and a new amphibole plagioclase geothermometer there is currently a dearth of reliable thermobarometers for many hornblende and plagioclase bearing rocks such as granitoids and amphibolites a semi empirical thermodynamic evaluation of the available experimental data on amphibole plagioclase assemblages leads to a new thermometer based on the aliv content of amphibole coexisting with plagioclase in silica saturated rocks the principal exchange vector in amphiboles as a function of temperature in both the natural and experimental studies is left na square 1 right a left alsi 1 right t1 we have analysed the data using 3 different amphibole activity models to calibrate the thermometer reactions 1 edenite 4 quartz tremolite albite 1 2 pargasite 4 quartz hornblende albite 2 the equilibrium relation for both 1 and 2 leads to the proposed new thermometer t frac 0 677p 48 98 y 0 0429 0 008314 ln k and k left frac si 4 8 si right x ab plag where si is the number of atoms per formula unit in amphiboles with p in kbar and t in k the term y represents plagioclase non ideality rtln ab from darken s quadratic formalism dqf with y 0 for xab 0 5 and y 8 06 25 5 1 xab 2 for xab 0 5 the best fits to the data were obtained by assuming complete coupling between al on the t1 site and na in the a site of amphibole and the standard deviation of residuals in the fit is 38 c the thermometer is robust to ferric iron recalculation procedures from electron probe data and should yield temperatures of equilibration for hornblende plagioclase assemblages with uncertainties of around 75 c for rocks equilibrated at temperatures in the range 500 1100 c the thermometer should only be used in this temperature range and for assemblages with plagioclase less calcic than an92 and with amphiboles containing less than 7 8 si atoms pfu good results have been attained on natural examples from greenschist to granulite facies metamorphic rocks as well as from a variety of mafic to acid intrusive and extrusive igneous rocks our analysis shows that the pressure dependence is poorly constrained and the equilibria are not suitable for barometry

sedimentary record of recent tsunamis in the huelva estuary southwestern spain abstract the coast of the gulf of cadiz has been repeatedly struck by tsunamis during the late holocene and the historic period historical documents record at least seven catastrophic tsunamis affecting this coast while others have been detected by oceanic instruments nevertheless very few studies have documented the sedimentary record of these tsunamis in the low energy coastal environments of the gulf of cadiz the huelva estuary is located at the central sector of the gulf of cadiz and is a mesotidal estuary fed by the tinto and odiel rivers the mean tidal range of the huelva estuary is ca 2 m and the mean significant wave height is ca 0 5 m the outer part of the estuary is characterized by extensive sand rich sedimentary bodies of marine origin whereas the central and inner parts are infilled by muddy tidally deposited sediment bodies recorded within these estuarine sediment bodies are five laterally continuous shelly units these units display many of the typical characteristics of tsunami deposits each typically comprises an erosional base followed by a fining upwards sequence that begins with the shell accumulation and ends with bioturbated muddy sand the results of 14 c ages and recent radionuclides accumulation rates in this study illustrate that these five tsunami deposits correspond with known events that occurred in ad 1755 1531 949 1033 881 and 395 381 all of which are documented in historical sources

landward fining from multiple sources in a sand sheet deposited by the 1929 grand banks tsunami newfoundland abstract a sandy deposit from the 1929 grand banks tsunami in newfoundland contains sediment from two distinct sources one from an inferred gravel shoreline close to the deposit and one from a sandy dune some 200 m seaward of the deposit the deposit ranges from 0 to 15 cm thick and is composed of a bimodal mix of fine and coarse sand we took approximately 100 core samples of this deposit in an attempt to characterize lateral grain size trends within the sand although the coarse fraction does fine with distance inland the fine fraction does not change size over the study area and the aggregate grain size changes in no systematic way we interpret this deposit to represent the mixture of material picked up at the bar with material picked up at the gravel shoreline the bar material does not fine in part because it is already fairly well sorted but also because it is far from its source the shoreline material on the other hand is poorly sorted so that the tsunami took only those grains it was capable of moving and deposited them near their source we estimated the size of the tsunami by determining the flow depth flow velocity combinations required to advect sand from the bar to the back of the deposit and by estimating the shear velocity required for motion of the largest grain we found during our survey this modeling indicates an average flow depth of about 2 5 2 8 m over the area at a flow velocity of 1 9 2 2 m s this estimate compares well with eyewitness accounts of a maximum flow depth of 7 m at the shoreline if our estimate represents an average over the whole study area

nearshore tsunami inundation model validation toward sediment transport applications model predictions from a numerical model delft3d based on the nonlinear shallow water equations are compared with analytical results and laboratory observations from seven tsunami like benchmark experiments and with field observations from the 26 december 2004 indian ocean tsunami the model accurately predicts the magnitude and timing of the measured water levels and flow velocities as well as the magnitude of the maximum inundation distance and run up for both breaking and non breaking waves the shock capturing numerical scheme employed describes well the total decrease in wave height due to breaking but does not reproduce the observed shoaling near the break point the maximum water levels observed onshore near kuala meurisi sumatra following the 26 december 2004 tsunami are well predicted given the uncertainty in the model setup the good agreement between the model predictions and the analytical results and observations demonstrates that the numerical solution and wetting and drying methods employed are appropriate for modeling tsunami inundation for breaking and non breaking long waves extension of the model to include sediment transport may be appropriate for long non breaking tsunami waves using available sediment transport formulations the sediment deposit thickness at kuala meurisi is predicted generally within a factor of 2

granulites in the tongbai area qinling belt china geochemistry petrology single zircon geochronology and implications for the tectonic evolution of eastern asia the tongbai area of the eastern qinling belt in china includes granulite grade metamorphic assemblages qinling complex which were previously regarded as archean to early proterozoic in age and belonging to the southern margin of the north china plate craton our petrological and geochemical data characterize these rocks as two pyroxene granulites and garnet granulites which formed at temperatures of 757 840 c and pressures of about 9 5 kbar and are now found as xenoliths in granodioritic gneisses the protoliths of these rocks were granodiorites and tholeiitic basalt or gabbro the 207pb 206pb ratios derived from evaporation of single zircons yield ages of 470 20 and 470 14 ma respectively for the basic granulites which we interpret to reflect the time of protolith emplacement these are intruded by a 435 14 ma granodioritic gneiss post dating granulite formation a metaquartzite sample contains detrital zircons as old as 2555 8 ma two samples of granitoid gneiss from the tongbai complex s of the qinling granulites have single zircon 207pb 206pb evaporation ages of 776 8 and 746 10 ma respectively and document late proterozoic igneous activity we suggest that the qinling granulites document an important and hitherto unknown phase of early silurian crustal thickening following subduction and continental collision and that both the qinling and tongbai complexes were part of the southern margin of the north china craton prior to this event and record late proterozoic igneous activity

spatial thickness variability of the 2011 tohoku oki tsunami deposits along the coastline of sendai bay abstract soon after the 2011 tohoku oki event approximately 1300 tsunami deposit thickness data were collected spatially by the governors to cover the entire tsunami affected area sendai plain along the sendai bay coastline this dataset along with high resolution and high precision data of flow depth and pre tsunami and post tsunami elevation enables us first to conduct a direct comparison of the sedimentation and erosion volumes as well as the tsunami hydrodynamic features e g flow depth and sediment thickness the total balance of sedimentation and erosion volumes revealed that the volume of tsunami deposited sediments can be explained roughly using the erosion volumes at the beach and sand dunes for sandy deposits and at rice paddy fields for muddy deposits both the flow depth and sediment thickness showed positive correlations with the distance from the shoreline while sediment thickness is no correlation to the elevation except in the zone closest to the shoreline where erosion is present in addition a statistical relation was found between the flow depth and sediment thickness in fact the frequency distribution of sediment concentration defined here as the sediment thickness divided by the maximum flow depth at each survey site fits well with the logarithmic normal distribution with geometric average of about 2 this fit indicates that the tsunami deposits on the sendai plain can be explained generally if we simply assume that the saturated level of the sediment concentration in the flow is limited to about 2 on average irrespective of the grain size such a simple explanation might be applicable only for the tsunami deposits on the sendai plain because the topography is remarkably flat and low therefore the tsunami inundation process is relatively simple nevertheless a possible relation between tsunami flow depth and sediment thickness suggested here would be very useful to consider the ideal sedimentary process of the tsunami deposits and to improve forward and inverse modelings

deposits flow characteristics and landscape change resulting from the september 2009 south pacific tsunami in the samoan islands the september 29th 2009 tsunami caused widespread coastal modification within the islands of samoa and northern tonga in the south pacific preliminary measurements indicate maximum runup values of around 17 m okal et al 2010 and shore normal inundation distances of up to 620 m jaffe et al 2010 geological field reconnaissance studies were conducted as part of an unesco ioc international tsunami survey team survey within three weeks of the event in order to document the erosion transport and deposition of sediment by the tsunami data collected included a general morphology and geological characteristics of the coast b evidence of tsunami flow inundation flow depth and direction wave height and runup c surficial and subsurface sediment samples including deposit thickness and extent d topographic mapping and e boulder size and location measurements four main types of sedimentary deposits were identified a gravel fields consisting mostly of isolated cobbles and boulders b sand sheets from a few to 25 cm thick c piles of organic mostly vegetation and man made material forming debris ramparts and d surface mud deposits that settled from suspension from standing water in the tsunami aftermath tsunami deposits within the reef system were not widespread however surficial changes to the reefs were observed

diamond from the dabie shan metamorphic rocks and its implication for tectonic setting diamond occurs in ultrahigh pressure metamorphic rocks from dabie shan anhui province eastern china diamond bearing rocks include eclogite gamet pyroxenite and jadeitite diamond occurs in a mineral assemblage with coesite and jadeite the diamonds and diamondiferous rocks of dabie shan are interpreted to be the products of ultrahigh pressure metamorphism in the underthrust basement of the yangtze continental plate during the early mesozoic at greater than 4 0 gigapascals and 900 c this interpretation is based on the distribution of rock units the stability field of diamond and isotopic data indicating a crustal origin for the rocks most diamonds occur as euhedral inclusions in garnets and are 10 to 60 micrometers across although some are up to 700 micrometers across

the quest for the africa eurasia plate boundary west of the strait of gibraltar the missing link in the plate boundary between eurasia and africa in the central atlantic is presented and discussed a set of almost linear and sub parallel dextral strike slip faults the swim1 faults that form a narrow band of deformation over a length of 600 km coincident with a small circle centred on the pole of rotation of africa with respect to eurasia was mapped using a new swath bathymetry compilation available in the area offshore sw portugal these faults connect the gloria fault to the rif tell fault zone two segments of the plate boundary between africa and eurasia the swim faults cut across the gulf of cadiz in the atlantic ocean where the 1755 great lisbon earthquake m 8 5 8 7 and tsunami were generated providing a new insight on its source location

tsunami sedimentation associated with the lisbon earthquake of 1 november ad 1755 boca do rio algarve portugal a description is given of a distinctive marine deposit at boca do rio on the algarve coast of portugal it is proposed here that the sediment accumulation was deposited by the tsunami generated by the lisbon earthquake of 1 november ad 1755 the deposit exhibits sedimentary characteristics quite unlike other coastal sediment accumulations that are deposited by more moderate wave regimes these include laterally continuous sand layers chaotic pebble horizons large amounts of gravel sized shell debris and distinctive assemblages of marine microfossils a preliminary attempt is made here to use the empirical field and laboratory data to define more clearly the processes of coastal sedimentation that characterize tsunami runup the use of tsunami sediments as time synchronous marker horizons is also discussed

modelling storm impacts on beaches dunes and barrier islands a new nearshore numerical model approach to assess the natural coastal response during time varying storm and hurricane conditions including dune erosion overwash and breaching is validated with a series of analytical laboratory and field test cases innovations include a non stationary wave driver with directional spreading to account for wave group generated surf and swash motions and an avalanching mechanism providing a smooth and robust solution for slumping of sand during dune erosion the model performs well in different situations including dune erosion overwash and breaching with specific emphasis on swash dynamics avalanching and 2dh effects these situations are all modelled using a standard set of parameter settings the results show the importance of infragravity waves in extending the reach of the resolved processes to the dune front the simple approach to account for slumping of the dune face by avalanching makes the model easily applicable in two dimensions and applying the same settings good results are obtained both for dune erosion and breaching

modeling tsunamis from earthquake sources near gorringe bank southwest of portugal the azores gibraltar fracture zone with the huge bathymetric reliefs in the area southwest of portugal is believed to have been the source of large historic tsunami events this report describes simulations of tsunami generation and propagation from sources near the gorringe bank the well documented 1969 tsunami event is examined both with a ray tracing technique and with finite difference models based on various shallow water equations both methods show that the most likely source location is southeast of the gorringe bank near the epicenter location determined from seismic data the tsunami source is calculated by formulas given by okada 1985 for surface deformation of an elastic half space caused by faulting observed wave amplitude and travel time and values computed from an initial wave field according to okada 1985 formulas show acceptable agreement for most stations along the coast of portugal and spain however in order to explain a large primary wave with downward displacement observed on the coast of morocco an alternative source model with a larger area of downward displacement has been introduced this also leads to a better overall fit with observed travel time implications for disastrous events as the one in 1755 are also discussed linear hydrostatic shallow water models are used for most of the simulations but the importance of nonlinearity and dispersion is examined with the boussinesq equations the sensitivity of the solution to changes in the location and the strength of the source is discussed and a series of grid refinement studies are performed in order to assess the accuracy of the simulations

calculation of co 2 activities using scapolite equilibria constraints on the presence and composition of a fluid phase during high grade metamorphism thermodynamic and phase equilibrium data for scapolite have been used to calculate co2 activities aco2 and to evaluate the presence or absence of a fluid phase in high grade scapolite bearing meta anorthosite granulites calc silicates and mafix xenoliths the assemblage scapolite plagioclase garnet quartz may be used to calculate or limit aco2 by the reaction meionite quartz grossular anorthite co2 granulites from four high grade terranes grenville province canada sargut belt india furua complex tanzania bergen arcs norway yield aco2 0 4 1 with most 0 7 for scapolite bearing granulites from the furua complex in which aco2 0 9 calculated h2o activities ah2o based on phlogopite dehydration equilibria are uniformly low 0 1 0 2 the aco2 calculated for meta anorthosite from the grenville province ontario ranges from 0 2 to 0 8 for grenville meta anorthosite also containing epidote the ah2o calculated from clinozoisite dehydration ranges from 0 2 to 0 6 calc silicates from the grenville sargur and furua terranes mostly yield aco2 1 the calculated fluid activities are consistent with metamorphism 1 in the presence of a mixed co2 h2o fluid phase in which co2 is the dominant fluid species but other c o h s species are minor 2 in the absence of a bulk fluid phase fluid absent metamorphism or 3 in the presence of a fluid bearing melt phase the results for many granulites and grenville meta anorthosite are consistent with the presence of a co2 rich mixed co2 h2o fluid phase in contrast the relatively restricted and low values of aco2 for calc silicates require an h2o rich fluid or absence of a fluid phase during metamorphism the range of values for xenoliths are most consistent with absence of a fluid phase the primary implication of these results is that a co2 rich fluid accounts for the reduced ah2o in scapolite bearing granulites however scapolite may be stable with a wide range of fluid compositions or in the absence of a fluid phase and the presence of scapolite is not a priori evidence of a co2 rich fluid phase in addition close association of scapolite free mafic granulites with scapolite bearing granulites having identical mineral compositions in the furua complex and the absence of scapolite from most granulite terranes implies that a co2 rich fluid phase is not pervasive on an outcrop scale or common to all granulite terranes

regional ultrahigh pressure coesite bearing eclogitic terrane in central china evidence from country rocks gneiss marble and metapelite the dabie mountains represent a fault bounded coesite bearing eclogite gneissic terrane within the collisional belt between the sino korean and yangtze cratons the following geologic evidence indicates that this terrane has been subjected to regional ultrahigh pressure metamorphism 1 the country rocks have a metamorphic pressure temperature evolution compatible with that of the eclogites on the basis of the occurrence of quartz pseudomorphs after coesite calcite pseudomorphs after aragonite relict high pressure assemblages in different rock types of the country rocks and consistent comparable compositional zonations of garnets in both country rocks and eclogites 2 peak metamorphic pressure temperature conditions consistently decrease both from east to west in the collisional belt and from north to south in the dabie mountains and clockwise pressure temperature paths are common for eclogites over the region 3 layered eclogites interbedded with gneisses and amphibolites contain omphacite kyanite and garnet indicating a minimum pressure of 20 kbar at 600 c for formation of these rocks

sedimentary record of a tsunami during roman times bay of cadiz spain abstract historical data show that the gulf of cadiz has been exposed to destructive tsunamisduring at least the past 2000 yr the last tsunami was generated by the ad 1755 lisbon earthquake which affected the atlantic coasts of spain portugal and morocco today these littoral areas areintensely populated and the expected damage could be much greater tsunami studies are of greatimportance in helping to determine the recurrence interval of these events the presence of washover fan deposits on the inland margin of the valdelagrana spit bar cadiz spain indicates the occurrence of a high energy marine event ca 2300 cal yr bp historical geomorphological sedimentological palaeontological and geochronological data suggest that atsunami could have affected the area during roman times copyright 2002 john wiley sons ltd journal of quaternary science keywords tsunami deposits grain size palaeontology gulf of cadiz south spain introduction investigations of the geological records of past tsunamis arean important tool in helping to determine the recurrenceinterval of such events in a region these investigations arealso the only way of determining the prehistoric occurrenceand tsunami hazard in areas of infrequent seismic activity however at present it is dif cult to distinguish betweentsunami deposits and those laid down by other high energyevents such as a storm surge or hurricane recent work bygoff et al 2001 has helped to identify a series of diagnosticcriteria for tsunami deposits and research is underway tohighlight the differences between these and other high energyevents goff and chagu e goff in preparation j goff personalcommunication 2002 wave hydrodynamics the speci ccoastal setting morphology orientation availability and typeof sediments depositional environments tsunami magnitudeand tidal range are all factors that help to de ne the type andpreservation of tsunami deposits furthermore the ability todetermine the tsunamigenic source largely depends upon thepalaeoseismic and historical record e g goff et al 2001

tsunami induced morphological change a model based impact assessment of the 1755 tsunami in ne atlantic from the morocco coast abstract tsunamis can be responsible for coastal geomorphic crises extensively inundated coasts can suffer widespread and dramatic changes in their morphology due to sediment erosion transport and deposition processes in this paper we investigate the tsunami induced morphological changes on coasts prone to inundation and how sediment transport is controlled by both tsunami and sediment characteristics we focus on a tsunami prone coast in the ne atlantic tangier morocco that experienced the 1755 lisbon tsunami we use a coupled hydrodynamic and morphodynamic numerical model together with high resolution digital elevation and sedimentary models to simulate the impact of tsunamis on the morphology and sediment distribution of tangier bay due to the uncertainty on the source and effects of the 1755 event we consider two 1755 like tsunamigenic scenarios that have the potential to cause different levels of inundation results show that the coastal zone of tangier can undergo substantial changes in morphology and sediment distribution following the tsunami impact for the selected scenarios the volume of sediments mobilized at both the offshore and onshore zones of the tangier site ranges from 30 000 to 200 000 m3 moreover the presence of mobile sediments and conditions favoring tsunami shoaling lead to an increase in wave impact on the coastal configuration conversely the presence of the breakwaters helps to protect the tangier coast by limiting the extent of the affected area the results of this study suggest that the assessment of tsunami induced coastal impact should include the effect on morphology

expanding the proxy toolkit to help identify past events lessons from the 2004 indian ocean tsunami and the 2009 south pacific tsunami article i nfo some of the proxies used to identify palaeotsunamis are reviewed in light of new findings following the 2004 indian ocean tsunami and the 2009 south pacific tsunami and a revised toolkit provided the new application of anisotropy of magnetic susceptibility ams to the study of tsunami deposits and its usefulness to determine the hydrodynamic conditions during the emplacement of tsunami sequences together with data from grain size analysis are presented the value of chemical proxies as indicators of saltwater inundation associated marine shell and or coral high energy depositional environment and possible contamination is demonstrated and issues of preservation addressed we also provide new findings from detailed studies of heavy minerals new information gathered during the unesco international oceanographic commission ioc international tsunami survey of fine onshore sediments following the 2009 south pacific tsunami is presented and includes grain size chemical diatom and foraminifera data the tsunami deposit varied ranging from fining upward sand layers to thin sand layers overlain by a thick layer of organic debris and or a mud cap grain size characteristics chemical data and microfossil assemblages provide evidence for marine inundation from near shore and changes in flow dynamics during the tsunami

a numerical model for tsunami induced morphology change we describe the development of a time resolved model for tsunami induced morphology change based on an existing boussinesq model for weakly dispersive free surface waves coupled to a depth integrated model for sediment concentration and an equation for bed level change the model allows for spatial variability in bottom friction coefficients and accounts for the presence of non erodible beds or finite depths of available sediment the model is verified using one laboratory data set and against field observations of morphology change in the crescent city ca harbor during the 2011 tohoku tsunami event the model is then applied to a hypothetical example illustrating the impact of tsunami inundation on an undeveloped barrier island

flow speed estimated by inverse modeling of sandy sediment deposited by the 29 september 2009 tsunami near satitoa east upolu samoa abstract sandy deposits from the 29 september 2009 tsunami on the east coast of upolu samoa were investigated to document their characteristics and used to apply an inverse sediment transport model to estimate tsunami flow speed sandy deposits 6 to 15 cm thick formed from 25 to 250 m inland sedimentary layers in the deposits that are defined by vertical grain size variation and contacts are interpreted to have formed during onshore runup of two waves deposits at 3 locations 100 170 and 240 m inland contained two layers that are predominately normally graded 80 but contained massive sections 15 and inversely graded sections 5 at their bases about 75 of the total thickness of normally graded intervals exhibits a signature of sediment falling out of suspension at their top this type of grading termed suspension grading here was first recognized in turbidity current deposits and is characterized by the entire distribution shifting finer upwards in a layer as high settling velocity coarser material deposits first and low settling velocity finer material deposits last the jaffe and gelfenbaum 2007 inverse sediment transport model was applied to intervals within layers that exhibited suspension grading to estimate tsunami flow speed and was able to reproduce the general trends of the observed suspension grading a key unknown input in the modeling is the bottom roughness for a bottom roughness parameterization using a manning s n of 0 03 equivalent to a z0 0 006 m for the observed flow depths of 2 3 m flow speeds calculated for the 2 layers at the 3 locations were 3 8 3 6 and 3 7 m s bottom layer earlier wave and 4 4 4 4 and 4 1 m s top layer later wave at 100 170 and 240 m inland respectively these estimates are consistent with the 3 8 m s tsunami flow speed from boulder transport calculations and result in froude numbers of 0 7 1 0 when maximum measured flow depths are used because the inverse model assumes the deposit was formed by sediment falling out of suspension care must be taken to model only intervals of the deposit exhibiting suspension grading including intervals deposited by either bedload or suspended load transport convergences result in higher and sometimes unrealistic tsunami flow speed estimates

runup of solitary waves on a circular island this is a study of the interactions of solitary waves climbing up a circular island a series of large scale laboratory experiments with waves of different incident height to depth ratios and different crest lengths is described detailed two dimensional run up height measurements and time histories of surface elevations around the island are presented a numerical model based on the two dimensional shallow water wave equations including runup calculations was developed numerical model predictions agreed very well with the laboratory data and the model was used to study wave trapping and the effect of slope under certain conditions enhanced runup and wave trapping on the lee side of the island were observed suggesting a possible explanation for the devastation reported by field surveys in babi island off flores indonesia and in okushiri island japan

seismic moment assessment of earthquakes in stable continental regions iii new madrid 1811 1812 charleston 1886 and lisbon 1755 summary the sizes of three major or great historical earthquakes are reassessed using the isoseismal area regression tools developed in parts i and ii of this study of stable continental region scr seismicity the earthquakes are 1811 new madrid central united states and its following sequence 1886 charleston coastal south carolina and 1755 lisbon oceanic intraplate off the continental shelf of portugal the analysis confirms the large size of these events and for the first time places constraints on the uncertainty of their seismic moment release because of the exceptionally low seismic wave attenuation of eastern north america ena a separate north american regression of seismic moment on isoseismal area was developed additionally the unknown western extents of the new madrid isoseismal areas were calibrated with the patterns of the m 6 3 6 6 1843 and 1895 earthquakes application of part ii analysis procedures with these corrections yields new madrid size estimates expressed as moment magnitude of m 8 1 0 31 for the 1811 december 16 m 7 8 0 33 for the 1812 january 23 and m 8 0 0 33 for the 1812 february 7 principal events the charleston earthquake s magnitude decreases from m 7 4 to m 7 3 0 26 after compensation for the effect of coastal plain sediments on its inner isoseismals intensity regressions for lisbon are calibrated against the isoseismal pattern of the nearly co located m 7 8 1969 st vincent earthquake which in this case increases the predicted size of lisbon from m 8 4 to m 8 7 0 39 these size estimates are supported by data from independent phenomena extent and severity of liquefaction the maximum distance of induced landslides and for lisbon tsunami wave amplitudes estimated source parameters are controlled by crustal or lithospheric temperature which governs the depth extent of brittle faulting using estimated continental and oceanic geotherms viable fault lengths are 30 80 km for charleston 120 180 km for 1811 new madrid and 180 280 km for lisbon for average displacements of 2 4 m 8 11 m and 10 14 m respectively and for average static stress and strain drops at the estimated seismic moments of this study the 1811 new madrid and the 1755 lisbon events are respectively the largest known scr and oceanic lithosphere earthquakes

the origins of granulites a metamorphic perspective although many recent reviews emphasize a uniformity in granulite pressure temperature p t conditions and paths granulites in reality preserve a spectrum of important petrogenetic features which indicate diversity in their modes of formation a thorough survey of over 90 granulite terranes or occurrences reveals that over 50 of them record p t conditions outside the 7 5 1 kbar and 800 50 c average granulite regime preferred by many authors in particular an increasing number of very high temperature 900 1000 c terranes are being recognized both on the basis of distinctive mineral assemblages and geothermobarometry petrogenetic grid and geothermobarometric approaches to the determination and interpretation of p t histories are both evaluated within the context of reaction textures to demonstrate that the large range in p t conditions is indeed real and that both near isothermal decompression itd and near isobaric cooling ibc p t paths are important amphibolite granulite transitions promoted by the passage of co 2 rich fluids as observed in southern india and sri lanka are exceptional and not representative of fluid related processes in the majority of terranes it is considered on the contrary that fluid absent conditions are typical of most granulites at or near the time of their recorded thermal maxima itd granulites are interpreted to have formed in crust thickened by collision with magmatic additions being an important extra heat source erosion alone is not however considered to be the dominant post collisional thinning process instead the itd paths are generated during more rapid thinning 1 2 mm yr exposure related to tectonic exhumation during moderate rate or waning extension ibc granulites may have formed in a variety of settings those which show anticlockwise p t histories are interpreted to have formed in and beneath areas of voluminous magmatic accretion with or without additional crustal extension ibc granulites at shallow levels very rapid 5 mm yr extensional thinning subsequent to collision it is suggested that the preservation of ibc paths rather than itd paths in many granulites is primarily related to the rate and timescale of extensional thinning of thickened crust and that hybrid itd to ibc paths should also be observed most ibc granulites and probably many itd granulites have not been exposed at the earth s surface as a result of the tectonic episodes which produced them but have resided in the middle and lower crust for long periods of time 100 2000 ma following these events the eventual exhumation of most granulite terranes only occur through their incorporation in later tectonic and magmatic events unrelated to their formation

probabilistic tsunami hazard in the northeast atlantic from near and far field tectonic sources in this article we present the first study on probabilistic tsunami hazard assessment for the northeast ne atlantic region related to earthquake sources the methodology combines the probabilistic seismic hazard assessment tsunami numerical modeling and statistical approaches we consider three main tsunamigenic areas namely the southwest iberian margin the gloria and the caribbean for each tsunamigenic zone we derive the annual recurrence rate for each magnitude range from mw 8 0 up to mw 9 0 with a regular interval using the bayesian method which incorporates seismic information from historical and instrumental catalogs a numerical code solving the shallow water equations is employed to simulate the tsunami propagation and compute near shore wave heights the probability of exceeding a specific tsunami hazard level during a given time period is calculated using the poisson distribution the results are presented in terms of the probability of exceedance of a given tsunami amplitude for 100 and 500 year return periods the hazard level varies along the ne atlantic coast being maximum along the northern segment of the morocco atlantic coast the southern portuguese coast and the spanish coast of the gulf of cadiz we find that the probability that a maximum wave height exceeds 1 m somewhere in the ne atlantic region reaches 60 and 100 for 100 and 500 year return periods respectively these probability values decrease respectively to about 15 and 50 when considering the exceedance threshold of 5 m for the same return periods of 100 and 500 years

the al 2 o 3 contents of enstatite in equilibrium with garnet in the system mgo al 2 o 3 sio 2 at 15 40 kbar and 900 1 600 c forty six reversed determinations of the al2o3content of enstatite in equilibrium with garnet were made in the p t range 15 40 kbar 900 1 600 c in the mgo al2o3 sio2 system starting materials were mixtures of synthetic pyrope al free enstatite and pyrope enstatite 5 12 al2o3 al2o3 contents in reversal run pairs closely approached common values from both the high and low al sides most experiments were done in a piston cylinder device using a nacl medium some runs at very high temperatures were made in pyrex nacl or pyrex talc assemblies the measured enstatite compositions expressed as mole fractions of mg2 mgal alsi3 o12 x opy en were fitted by a monte carlo method to the equilibrium condition begin gathered delta h 970 0 970 delta s 970 0 hfill mathop smallint limits 1 p delta v 970 0 dp mathop smallint limits 970 t delta s t 0 dt rt ln x opy en 0 hfill end gathered where the best fit parameters of h s and v 1 bar 970 k for the reaction pyrope opy are 2 040 cal mol 2 12 eu and 9 55 cc mol in addition to the determination of al2o3 contents of enstatite the univariant reaction pyrope forsterite enstatite spinel was reversibly located in the range 1 100 1 400 c a best fit line passes through 22 22 5 and 25 kbar at 1 040 1 255 and 1 415 c respectively our results for the univariant reaction are in agreement with previous studies of macgregor 1974 and haselton 1979 however comparison of the experimentally determined curve with thermochemical calculations suggests that there may be a small error in the tabulated h f 970 1 0 value for enstatite a value of 8 32 rather than 8 81 kcal mole charlu et al 1975 is consistent with the present data application of garnet enstatite spinel forsterite equilibria to natural materials is fraught with difficulties the effects of nonternary components are poorly understood and the low solubilities of al2o3 in enstatite under most geologically reasonable conditions make barometric or thermometric calculations highly sensitive more detailed studies including reversed determinations in low friction assemblies are sorely needed before the effects of important diluents such as fe ca and cr can be fully understood

coastal sedimentation associated with the june 2nd and 3rd 1994 tsunami in rajegwesi java abstract this paper presents the second detailed study of sediments deposited by modern tusnamis the first being that of the flores indonesia tsunami of december 1992 shi et al 1995 sediment cores were collected from areas in which eyewitnesses reported sediment deposition grain size analysis shows pronounced vertical variations in grain size as well as changes in standard deviation skewness and kurtosis that appear to be indicative of complex tsunami flooding vertical variations in grain size in individual cores are greater than spatial variations between cores taken along a transect completed perpendicular to the coastline the java tsunami deposited sediments do not show unequivocal evidence of local erosion but instead evidence for sediment transport and deposition is clear and is characterised by dominantly unimodal sediments with fine tailed distributions

petrogenesis of a high temperature metamorphic terrane a new tectonic interpretation for the north dabieshan central china the northern dabie terrane consists of a variety of metamorphic rocks with minor mafic ultramafic blocks and abundant jurassic cretaceous granitic plutons the metamorphic rocks include orthogneisses amphibolite migmatitic gneiss with minor granulite and metasediments no eclogite or other high pressure metamorphic rocks have been found granulites of various compositions occur either as lenses blocks or layers within clinopyroxene bearing amphibolite or gneiss the palaeosomes of most migmatitic gneisses contain clinopyroxene melanosomes and leucosomes are intimately intermingled tightly folded and may have formed in situ the granulites formed at about 800 830 c and 10 14 kbar and display near isothermal decompression p t paths that may have resulted from crust thickened by collision plagioclase amphibole coronae around garnets and matrix pi hbl assemblages from mafic and ultramafic granulites formed at about 750 800 c partial replacement of clinopyroxene by amphibole in gneiss marks amphibolite facies retrograde metamorphism amphibolite facies orthogneisses and interlayered amphibolites formed at 680 750 c and c 6 kbar formation of oligoclase orthoclase antiperthite after plagioclase took place in migmatitic gneisses at t 490 c in response to a final stage of retrograde recrystallization these p t estimates indicate that the northern dabie metamorphic granulite amphibolite facies terrane formed in a metamorphic field gradient of 20 35 c km 1 at intermediate to low pressures and may represent the sino korean hangingwall during triassic subduction for formation of the ultrahigh and high p units to the south post collisional intrusion of a mafic ultramafic cumulate complex occurred due to breakoff of the subducting slab

boulder deposition during major tsunami events a remarkable accumulation of marine boulders located above the present spring tide level has occurred in two coastal lowlands of the algarve portugal the size interval of the particles studied here is seldom reported in the literature in association with extreme events of coastal inundation thus making this study of relevance to many other coasts worldwide the spreads of boulders extend several hundred meters inland and well beyond the present landward limit of storm activity the marine origin of the boulders is demonstrated by well developed macro bioerosion sculpturing and in situ skeletal remains of endolithic shallow marine bivalves the good state preservation of the fossils within the boulders indicates that abrasion during transport and redeposition was not significant we envisage boulder deposition as having taken place during the lisbon tsunami of ad 1755 through the simultaneous landward entrainment of coarse particles from nearshore followed by rapid shoreward suspended dominated transport and non graded redeposition that excluded significant sorting by weight or boulder dimensions we use numerical hydrodynamic modeling of tsunami and storm waves to test the observational data on boulder dimensions density size distribution on the most likely processes of sediment deposition this work demonstrates the effectiveness of the study of boulder deposits in tsunami reconstruction copyright 2011 john wiley sons ltd

evaluating tsunami impact on the gulf of cadiz coast northeast atlantic the gulf of cadiz coasts are exposed to tsunamis emergency planning tools are now taking into account this fact especially because a series of historical occurrences were strikingly significant having left strong evidence behind in the mareographic records the geological evidence or simply the memory of the populations the study area is a strip along the algarve coast south portugal an area known to have been heavily impacted by the 1 november 1755 event in this study we use two different tsunami scenarios generated by the rupture of two thrust faults identified in the area corresponding to 8 1 8 3 magnitude earthquakes tsunami propagation and inundation computation is performed using a non linear shallow water code with bottom friction numerical modeling results are presented in terms of flow depth and current velocity with maximum values of 7 m and 8 m s for inundation depth and flow speed respectively these results constitute a valuable tool for local authorities emergency and decision planners to define the priority zones where tsunami mitigation measures must be implemented and to develop tsunami resilient communities

mapping active faults offshore portugal 36 n 38 n implications for seismic hazard assessment along the southwest iberian margin swath bathymetry and acoustic backscatter data from the southwest iberian margin which hosts the present day boundary between the european and african plates reveal the surficial expression of several fault structures 100 km offshore of portugal high resolution and multichannel seismic reflection profiles collected perpendicular to these structures show folding and reverse faulting of the quaternary units suggesting present day tectonic activity successive submarine landslide deposits at the base of the scarps provide evidence of cyclic fault activity the location and dimension of these newly identified structures agree with the modeled source suggested for the a d 1755 lisbon earthquake and tsunami possibly the most destructive event in western europe during historical time these fault escarpments and deformed seafloor sediments associated with a cluster of shallow seismicity suggest that these thrusts are active and may pose a significant earthquake and tsunami hazard to the coasts of portugal spain and morocco

comment on lisbon 1755 a case of triggered onshore rupture by susana p vilanova catarina f nunes and joao f b d fonseca the work published recently by vilanova et al 2003 in the bulletin of the seismological society of america proposes that the accounts of destruction and other effects reported in the lisbon area as a result of the 1 november 1755 earthquake are best explained by a local rupture on the lower tagus valley fault ltvf triggered by the static stress change produced by the main offshore source located in the gorringe area because of the potential impact of this hypothesis on the seismic hazard of the lisbon area we discuss and complement the evidence presented by vilanova and co workers concluding that the local rupture model should remain for the moment as an unsubstantiated speculation vilanova et al 2003 referred to herein as the authors or the paper compare the intensities reported for the 1755 earthquake in lisbon and algarve to conclude that lisbon intensities are abnormally high for the same distance in particular when compared with what was observed for the 28 february 1969 earthquake they interpreted this as the result of local rupture in figure 1 we re plot the macroseismic intensity as a function of the distance to the gorringe bank source presumed by the authors we can see that lower tagus valley intensities do not show any abnormal behavior similar plots could be made for all source areas proposed by other authors baptista 1998 baptista et al 1998a 1998b zitellini et al 1999 2001 terrinha et al 2003 with minor changes to the conclusion we reached previously the conclusions reached by the authors were based on their figure 8a from which intensity values for the algarve and portuguese west coast corresponding to distances greater than 350 km are missing figure 1 modified mercalli mm intensities for the 1755 earthquake plotted as a

reaction textures in calc silicate granulites from the bolingen islands prydz bay east antarctica implications for the retrograde p t path calc silicate granulites from the bolingen islands prydz bay east antarctica exhibit a sequence of reaction textures that have been used to elucidate their retrograde p t path the highest temperature recorded in the calc silicates is represented by the wollastonite and scapolite bearing assemblages which yield at least 760 c at 6 kbar based on experimental results the calc silicates have partially re equilibrated at lower temperatures down to 450 c as evidenced by the successive reactions 1 wollastonite scapolite calcite garnet co2 2 wollastonite co2 calcite quartz 3 wollastonite plagioclase garnet quartz 4 scapolite plagioclase calcite quartz 5 garnet co2 h2o epidote calcite quartz and 6 clinopyroxene co2 h2o tremolite calcite quartz the reaction sequence observed indicates that aco2 was relatively low in the wollastonite bearing rocks during peak metamorphic conditions and may have been further lowered by local infiltration of h2o from the surrounding migmatitic gneisses on cooling fluid activities in the bolingen calc silicates were probably locally variable during the granulite facies metamorphism and large scale co2 advection did not occur a retrograde p t path from the sillimanite stability field c 760 c at 6 kbar into the andalusite stability field c 450 c at 3 kbar is suggested by the occurrence of secondary andalusite in an adjacent cordierite sillimanite gneiss in which sillimanite occurs as inclusions in cordierite

survey of 2011 tohoku earthquake tsunami inundation and run up 1 at 14 46 local time on march 11 2011 a magnitude 9 0 earthquake occurred off the coast of northeast japan this earthquake generated a tsunami that struck japan as well as various locations around the pacific ocean with the participation of researchers from throughout japan joint research groups conducted a tsunami survey along a 2000 km stretch of the japanese coast more than 5300 locations have been surveyed to date generating the largest tsunami survey dataset in the world on the sendai plain the maximum inundation height was 19 5 m and the tsunami bore propagated more than 5 km inland along the ria coast from about 50 to 200 km north of sendai the narrow bays focused the tsunami waves generating the largest inundation heights and run ups the survey data clearly show a regional dependence of tsunami characteristics

evidence for intracontinental thrust related exhumation of the ultra high pressure rocks in china coesite and diamond bearing ultra high pressure metamorphic rocks produced during the triassic continental collision between the sino korean and yangtze plates are offset by about 530 km along the sinistral tanlu fault in eastern china the tanlu fault terminates abruptly south of the ultra high pressure metamorphic terrain in dabie shan and does not extend into the foreland fold belt along the yangtze river this suggests that in this region the mesozoic major sinistral displacement along the tanlu fault was transferred to southward directed thrusting which led to the exhumation of the ultra high pressure metamorphic rocks formed earlier postcollisional himalayan type intracontinental thrusting and concomitant erosion appear to be the main agents in the exhumation of the very high pressure metamorphic rocks in china

process based modeling of tsunami inundation and sediment transport 1 the infrequent and unpredictable nature of tsunamis precludes the use of field experiments to measure the hydrodynamic and sediment transport processes that occur instead these processes are often approximated from laboratory numerical and theoretical studies or inferred from observations of the resultant sediment deposits here delft3d a three dimensional numerical model is used to simulate the inundation and sediment transport of a tsunami similar in magnitude to the 26 december 2004 indian ocean tsunami over one measured and three idealized morphologies the model is first shown to match well the observations taken at kuala meurisi sumatra and then used to examine in detail the processes that occur during the tsunami the model predicts that at a given cross shore location the onshore flow accelerates rapidly to a maximum as the wavefront passes and then gradually decelerates before reversing direction and flowing offshore the onshore flow does not tend to zero everywhere at maximum inundation but instead flow reversal occurs near the shoreline even as the wavefront continues to inundate landward while some sediment is eroded by the passing wavefront the suspension of sandy sediment is dominated by the long duration high velocity backwash that occurs along the beach face and offshore of the shoreline some of the sediment suspended during backwash is advected shoreward by the subsequent wave creating large spatial gradients in the suspended sediment concentrations which may not be in equilibrium with the local hydrodynamics the inundation and transport of sediment during a tsunami can be affected by complexities in the morphological profile and interactions between multiple waves and many of the hydrodynamic and sediment transport processes predicted here are similar to analogous processes previously observed in the swash zone

delamination in collisional orogens during continental collision the weight of the downgoing slab may lead to extensional shearing in the descending plate permitting separation of the downdip dense oceanic lithosphere from the adjacent lighter continental lithospher separation may occur by means of a lithosphere penetrating normal sense shear zone by means of pure shear necking of the lithosphere or by some combination of these mechanisms during separation the continental crust attached to the lower plate may undergo an episode of extensional tectonics the proximity of asthenosphere to crust may result in syntectonic regional metamorphism and plutonism if the continents continue to converge following delamination a compressive tectonic regime will be reestablished in the crust the subsequent cooling of asthenosphere at the base of the crust may lead to the establishment of a continuous flat moho the likely imbrication of crustal and mantle lithologies during delamination and during the subsequent compressive tectonic regime as well as underplating associated with syntectonic plutonism may account for the seismic complexities observed at moho depths beneath some mountain belts

coastal changes in the sendai area from the impact of the 2011 tōhoku oki tsunami interpretations of time series satellite images helicopter borne video footage and field observations a combination of time series satellite imagery helicopter borne video footage and field observation is used to identify the impact of a major tsunami on a low lying coastal zone located in eastern japan a comparison is made between the coast protected by armoured engineered sea walls and the coast without changes are mapped from before and after imagery and sedimentary processes identified from the video footage the results are validated by field observations the impact along a natural coast with minimal defences is erosion focussed on the back beach along coasts with hard engineered protection constructed to defend against erosion the presence of three to six metre high concrete faced embankments results in severe erosion on their landward faces the erosion is due to the tsunami wave accelerating through a hydraulic jump as it passes over the embankment resulting in the formation of a ditch into which the foundations collapse engineered coastal defences are thus found to be small defence against highly energetic tsunami waves that overtop them there is little erosion or sedimentation of the whole beach and where active it mainly forms v shaped channels these channels are probably initiated during tsunami inflow and then further developed during tsunami backflow tsunami backflow on such a low lying area takes place energetically as sheet flow immediately after tsunami flooding has ceased subsequently when the water level landward of the coastal dune ridges falls below their elevation flow becomes confined to rivers and breaches in the coast formed during tsunami inflow enigmatic short lived strand lines are attributed to the slow fall of sea level after such a major tsunami immediately after the tsunami coastal reconstruction begins sourced from the sediment recently flushed into the sea by tsunami backflow

sediment transport part i bed load transport a method is presented which enables the computation of the bed load transport as the product of the saltation height the particle velocity and the bed load concentration the equations of motions for a solitary particle are solved numerically to determine the saltation height and particle velocity experiments with gravel particles transported as bed load are selected to calibrate the mathematical model using the lift coefficient as a free parameter the model is used to compute the saltation heights and lengths for a range of flow conditions the computational results are used to determine simple relationships for the saltation characteristics measured transport rates of the bed load are used to compute the sediment concentration in the bed load layer a simple expression specifying the bed load concentration as a function of the flow and sediment conditions is proposed a verification analysis using about 600 alternative data shows that about 77 of the predicted bed load transport rates are within 0 5 and 2 times the observed values

a simple model for calculating tsunami flow speed from tsunami deposits abstract this paper presents a simple model for tsunami sedimentation that can be applied to calculate tsunami flow speed from the thickness and grain size of a tsunami deposit the inverse problem for sandy tsunami deposits where grain size and thickness vary gradually in the direction of transport tsunami sediment transport is modeled as a steady spatially uniform process the amount of sediment in suspension is assumed to be in equilibrium with the steady portion of the long period slowing varying uprush portion of the tsunami spatial flow deceleration is assumed to be small and not to contribute significantly to the tsunami deposit tsunami deposits are formed from sediment settling from the water column when flow speeds on land go to zero everywhere at the time of maximum tsunami inundation there is little erosion of the deposit by return flow because it is a slow flow and is concentrated in topographic lows variations in grain size of the deposit are found to have more effect on calculated tsunami flow speed than deposit thickness the model is tested using field data collected at arop papua new guinea soon after the 1998 tsunami speed estimates of 14 m s at 200 m inland from the shoreline compare favorably with those from a 1 d inundation model and from application of bernoulli s principle to water levels on buildings left standing after the tsunami as evidence that the model is applicable to some sandy tsunami deposits the model reproduces the observed normal grading and vertical variation in sorting and skewness of a deposit formed by the 1998 tsunami

new insights of tsunami hazard from the 2011 tohoku oki event we report initial results from our recent field survey documenting the inundation and resultant deposits of the 2011 tohoku oki tsunami from sendai plain japan the tsunami inundated up to 4 5 km inland but the 0 5 cm thick sand deposit extended only 2 8 km 62 of the inundation distance the deposit however continued as a mud layer to the inundation limit the mud deposit contained high concentrations of water leachable chloride and we conclude that geochemical markers and microfossil data may prove to be useful in identifying the maximum inundation limit of paleotsunamis that could extend well beyond any preserved sand layer our newly acquired data on the 2011 event suggest that previous estimates of paleotsunamis e g 869 ad j gan earthquake and tsunami in this area have probably been underestimated if the 2011 and 869 ad events are indeed comparable the risk from these natural hazards in japan is much greater than previously recognized

tectonics of the qinling belt build up and evolution of eastern asia the structure and history of the qinling range which separates the north and south china cratons are a key to the tectonic evolution of eastern asia the mountain range is composed of a northern palaeozoic belt and a southern mesozoic belt the palaeozoic orogeny probably involved the closure of an oceanic basin along a north dipping subduction zone followed by south vergent obduction of ophiolites and intracontinental thrusting during the devonian the mesozoic belt appears to be the product of purely intracontinental shallow crustal deformation over a large decollement with at least 100 km of horizontal transport since the devonian both belts have been sliced by huge east west sinistral strike slip faults

how did the ad 1755 tsunami impact on sand barriers across the southern coast of portugal idl pest oe cte la0019 2013 plani2c ed481b 2014 132 0 post doc eu fp7 research project risc kit ga 2013 603458 e fct investigator program ref if 01047 2014

what brought them up exhumation of the dabie shan ultrahigh pressure rocks metamorphic coesite and diamond in the dabie shan eastern china testify to subduction of continental crust to 100 km depth exhumation of these ultrahigh pressure rocks through the crust encompassed two stages 1 south dipping foliation southeast plunging stretching lineation lineation parallel isoclinal folds and boudins indicate extreme subhorizontal shortening and subvertical extension during top to northwest shearing at 200 180 ma syntectonic recrystallization occurred at eclogite and amphibolite facies temperatures and at pressures below coesite stability 2 northwest southeast subhorizontal extension from 133 to 122 ma was concentrated within an asymmetric structural dome in a magmatic complex that forms the northern half of the dabie shan pluton cores at deep structural levels have weak hypersolidus fabrics and pluton carapaces are mylonitic gneisses formed at upper amphibolite facies conditions deformation is concentrated in greenschist facies mylonites and ultramylonites along the xiaotian mozitang detachment fault at the northern topographic limit of the dabie shan our preferred exhumation model involves two stages triassic indentation vertical extrusion and erosion followed by cretaceous plate margin transtension

sedimentary features of tsunami deposits in carbonate dominated beach environments a case study from the 25 october 2010 mentawai tsunami this study provides a case history of tsunami deposition in a carbonate dominated environmental setting we present the results of a sedimentological investigation conducted on deposits formed by the 25 october 2010 mentawai island tsunami and report on deposits analyzed at three sites on north pagai island sabeu gunggung macaroni resort and tumalei the deposits are mainly composed of medium to coarse sand sized fragments of corals shells and foraminifera with thickness ranging from 3 to 26 cm the deposits consist of two to five layers with fining upward trends dominating local topography noticeably affects the thickness number of layers and distribution of tsunami deposits the foraminiferal assemblage and diversity vary at each sample point along transect and between different transects based on the foraminiferal content most of the deposit material likely came from shallower depths in addition density distribution of the tsunami deposit material exhibits some degree of variability in terms of the range of densities in each sample and the trend of the overall density along each transect in contrast to heavy mineral dominated deposits the density of carbonate grains as a function of size may be an important consideration when carbonate dominated deposits are used to interpret hydraulic conditions that created a particular tsunami deposit since there are relatively few studies of tsunami deposits in carbonate dominated environmental settings such as the mentawai islands our study provides a useful case history of tsunami deposition in such an environmental setting

flow speed estimated by inverse modeling of sandy tsunami deposits results from the 11 march 2011 tsunami on the coastal plain near the sendai airport honshu japan abstract tsunami deposits contain information about the flow that created them which can be interpreted to estimate tsunami magnitude sandy deposits near sendai airport are modeled using an inverse sediment transport model to explore the spatial and temporal variation of tsunami flow speed in the 11 march 2011 tohoku oki tsunami the 2011 deposits contain grain size signatures of both sediment transport convergences and sediment settling out of suspension sediment transport convergences form massive or inversely graded intervals sediment falling out of suspension forms a specific type of normal grading termed suspension grading the jaffe and gelfenbaum 2007 inverse sediment transport model which relates the thickness and bulk grain size of suspension graded intervals to tsunami flow speed was applied to 24 suspension graded intervals ranging in thickness from 2 to 4 cm at 7 trenches located from about 250 to 1350 m inland from the shoreline modeled tsunami flow speeds range from 2 2 to 9 0 m s and were strongly dependent on the choice of manning s n roughness parameterization flow speeds were highest from about 75 300 m landward of the forested sand dunes where the tsunami encountered lower roughness in a low lying area as it traveled downslope and decreased by 16 as the tsunami moved inland over the subsequent 596 m as many as 5 suspension graded intervals interpreted as forming during the onshore flow of up to 5 waves were identified at each location with a tendency for an inland decrease in the number of suspension graded intervals suggesting fewer waves inland tsunami flows tended to be fastest in the lower two intervals earlier waves and slowest in the uppermost interval last wave of the deposits modeled reconstructions of the suspension graded intervals at a vertical resolution of 1 cm reproduced observed upward fining of the distributions reasonably well supporting the use of the inverse model estimates of the time required to form 99 of the thickness of the suspension graded intervals ranged 2 to 5 min allowing that sediment falling from suspension could have formed these portions of the deposits in the time between waves application of the inverse model to determine paleotsunami flow speeds from deposits although now possible is complicated by uncertainty in roughness as inverse approaches to estimating roughness and tsunami flow speed improve the magnitude of paleotsunamis will be better understood and the ability to assess tsunami hazard from paleotsunami deposits will improve

evidence of high energy events in the geological record mid holocene evolution of the southwestern donana national park sw spain abstract four phases are distinguished in the mid holocene evolution of the southwestern donana national park sw spain based on the multidisciplinary study of sediments in drill cores in the oldest phase 5500 5400 cal years bp a coastal brackish lagoon occupied the central part of the study area partly enclosed by the donana spit and limited by fluvial levees an evolution from subtidal to intertidal conditions characterized the areas located close to the inner side of the donana spit during the same phase the following phase 5400 5200 cal years bp is characterized by a high energy event tsunami which caused the breakthrough of the donana spit and the creation of new littoral strands in the inner areas in the first period of the third phase 5200 4200 cal years bp estuarine infilling was probably the dominant process with the accumulation of phyllosilicate rich clays in the lagoon bed this was followed by a renewed phase of instability 4200 4100 cal years bp indicated by the presence of fine storm lain deposits and thicker probably tsunami induced shelly deposits the last phase 4100 3700 cal years bp comprises a an infilling period with a diminution of the marine influence and b two new high energy events which caused the erosion of the donana spit and the creation of new cheniers in the last 7000 years the comparison of these results with a revision of both geological and historical records has revealed the occurrence of twenty tsunamis at least during this period in portugal and southern spain evidences of these high energy events are washover fans bioclastic coarse sized layers within salt marsh deposits or the presence of giant boulders and pebbles the determination of the recurrence period is very difficult owing to the very scarce data although our data and other authors do not discard a possible periodicity of 2000 years for a cycle of two events separated by 300 400 years

sediment transport due to the 2011 tohoku oki tsunami at sendai results from numerical modeling abstract numerical modeling of sediment transport on the sendai plain in northeast japan which was caused by the 2011 tohoku oki tsunami was performed to investigate why onshore tsunami deposits included small amounts of marine materials and to explain the gap between the maximum inland extent of the recognizable sand layer and the limit of inundation the simulation results generally corresponded with the thicknesses of the deposits observed in the field by previous studies the simulation revealed that the tsunami caused a significant amount of erosion on the beach and in the coastal forest however erosion was significantly limited on the offshore seafloor in addition the bore of the highest tsunami wave offshore limited the amount of suspended sediment due to a steep bathymetric profile of the shoreface and a moderate initial drop in water level prior to the arrival of the bore this resulted in limited suspension and shoreward advection of the sediments and a minor contribution of the seafloor sediments to the onshore tsunami deposit visualization of the onshore sediment transport indicated that the sediment transport was significantly affected by artificial topographic features the flow speed and height varied across the topographic highs and sediments were trapped on the seaward side of these highs in coastal areas the sediment supply was limited due to the presence of engineered dikes along the coast in inland areas embankments of paved roadways caused increased deposition on the seaward sides of the embankments and less deposition on the leeward sides of the embankments although some aspects of the relevant physics were not fully implemented in the model in which uncertainties exist the results may explain the processes and consequences of sedimentation from a tsunami event

tsunami inundation and sediment transport in a sediment limited embayment on american samoa abstract field observations and numerical simulations are used to explore tsunami inundation and sediment transport in an embayment fagafue bay on the north side of tutuila american samoa during the 29 september 2009 south pacific tsunami field observations of the nearshore bathymetry and topography tsunami flow depth and sediment deposition and extent of movable sandy sediment remaining on the beach were collected during two field surveys approximately two and five weeks after the tsunami onshore measurements of flow depth at forty eight locations indicate the wave inundated almost 250 m onshore with a depth exceeding 7 m locally the tsunami deposited patchy areas of sediment up to 0 2 m thick interspersed with a thin dusting

reply to the comment on physical and stable isotope evidence for formation of secondary calcite and silica in the unsaturated zone yucca mountain nevada by y v dublyansky s e smirnov and g p palyanova

tsunamis as geomorphic crises lessons from the december 26 2004 tsunami in lhok nga west banda aceh sumatra indonesia abstract large tsunamis are major geomorphic crises since they imply extensive erosion sediment transport and deposition in a few minutes and over hundreds of kilometres of coast nevertheless little is known about their geomorphologic imprints the december 26 2004 tsunami in sumatra indonesia was one of the largest and deadliest tsunamis in recorded human history we present a description of the coastal erosion and boulder deposition induced by the 2004 tsunami in the lhok nga bay located to the west of banda aceh northwest sumatra the geomorphological impact of the tsunami is evidenced by beach erosion some beaches have almost disappeared destruction of sand barriers protecting the lagoons or at river mouths numerous erosion escarpments typically in the order of 0 5 1 5 m when capped by soil and more than 2 m in dunes bank erosion in the river beds the retreat along the main river is in the order of 5 15 m with local retreats exceeding 30 m large scars typically 20 50 cm deep on slopes dislodgement of blocks along fractures and structural ramps on cliffs the upper limit of erosion appears as a continuous trimline at 20 30 m a s l locally reaching 50 m the erosional imprints of the tsunami extend to 500 m from the shoreline and exceed 2 km along riverbeds the overall coastal retreat from lampuuk to leupung was 60 m 550 000 m 2 and locally exceeded 150 m over 276 000 m 3 of coastal sediments were eroded by the tsunami along the 9 2 km of sandy coast the mean erosion rate of the beaches was 30 m 3 m of coast and locally exceeded 80 m 3 m the most eroded coasts were tangent to the tsunami wave train which was coming from the southwest the fringing reefs were not efficient in reducing the erosional impact of the tsunami the 220 boulders measured range from 0 3 to 7 2 m large typically 0 7 1 5 m with weights from over 50 kg up to 85 t we found one boulder less than 1 m large at 1 km from the coastline but all the others were transported less than 450 m 30 m and the moderate tsunamis height

source discriminants for near field tsunamis summary we present numerical simulations of tsunami run up in the near field for a data set of 72 models of sources involving both seismic dislocations and landslides by varying one by one the parameters describing the source and the receiving beach we are able to separate their individual influence on the amplitude and distribution of run up which we characterize by forming several dimensionless parameters principally the ratio i 2 of its maximum amplitude to its lateral extent along the beach we find that i 2 remains less than 10 4 for seismic dislocation sources but is greater than this threshold for all physically realistic models of underwater landslides thus it can be used as a discriminant for the nature of the source of a near field tsunami for seismic dislocations we also consider the ratio i 1 of maximum run up to seismic slip on the fault plane and validate numerically the previously suggested rule of thumb that this ratio cannot be much greater than 1 in the case of underwater landslides we show that the distribution of near field run up is primarily controlled by the 2 d wall of water displaced on the ocean surface as an initial condition to the simulation and is practically independent of its extension in the third dimension perpendicular to the beach we apply this approach to nine profiles of tsunami run up obtained experimentally during recent field surveys and show that our method successfully identifies the 1998 papua new guinea tsunami as having been generated by an underwater landslide thus confirming the results of shipboard and hydroacoustic investigations it also strongly suggests a similar mechanism for the generation of the near field aleutian tsunami of 1946 april 1