evidence for an earthquake and tsunami about 3100 3400 yr ago and other catastrophic saltwater inundations recorded in a coastal lagoon new zealand abstract okupe lagoon is 2 02 masl brackish and ponded behind two boulder banks at the northern end of kapiti island new zealand the sediments of the lagoon provide a record of late holocene environmental changes such as tectonic uplift catastrophic saltwater inundation and vegetation change five main events were identified over a 5300 yr record with a sixth representing a re evaluation of previous work an uplift event of 1 5 3 0 m and an associated tsunami are recorded and are inferred to have been caused by a local fault rupture possibly the northern extension of the wairau fault about 3360 40 yr bp two additional tsunami generated by ruptures of either the ohariu or wellington faults 1290 and 1220 ad respectively and either the wellington or alpine faults 1450 ad have been tentatively proposed two catastrophic saltwater inundations csis have also been identified one possibly a tsunami generated by either the wairarapa fault 500 ad or taupo eruption 190 ad the other about 4780 150 yr bp may relate to a local fault rupture however further work is needed to determine whether these are tsunami or storm surge related and they are therefore designated csis the sixth event is the 1855 tsunami recorded from a raised shore platform to the west of okupe lagoon

tsunami of december 26 2004 on the southwest coast of india post tsunami geomorphic and sediment characteristics this paper discusses the impact of the december 26 2004 tsunami on the geomorphic features and sediment characteristics along the southwest coast of india the data used include field observations made after the tsunami and the inferences drawn from the satellite imagery taken before and after the tsunami sediment samples collected from the inner shelf beach and estuarine environments were analyzed to understand post tsunami changes in grain size characteristics the tsunami eroded and transported landwards significant volumes of distinct black sands rich in heavy minerals from the shelf onto the beaches of the kerala region and up to 500 m inland of the present coast

frictional wave dissipation on a remarkably rough reef we present a week of observations of wave dissipation on the south forereef of palmyra atoll using wave measurements made in 6 2 m and 11 2 m of water offshore of the surf zone we computed energy fluxes and near bottom velocity equating the divergence of the shoreward energy flux to its dissipation by bottom friction and parameterizating dissipation in terms of the root mean square velocity cubed we find that the wave friction factor fw for this reef is 1 80 0 07 nearly an order of magnitude larger than values previously found for reefs we attribute this remarkably high value of fw to the complex canopy structure of the reef which we believe may be characteristic of healthy reefs this suggests that healthy reefs with high coral cover may provide greater coastal protection than do degraded reefs with low coral cover

numerical modeling of low frequency wave dynamics over a fringing coral reef abstract low frequency infragravity wave dynamics on a fringing coral reef were investigated using the numerical model xbeach roelvink et al 2009 first the skill of the model was evaluated in one and two dimensions based on its predictions of short waves 0 04 0 2 hz infragravity waves 0 004 0 04 hz and water level measurements tidal and wave setup obtained during a 2009 field study at ningaloo reef in western australia the model calibration was sensitive to friction coefficients for short waves and current infragravity bed friction which were assumed independent in this model study although the one dimensional cross shore model captured the gradients in the dominant hydrodynamic processes at the site a high current ig bed friction coefficient was required this resulted in an overestimation and a phase lag between the observed and predicted wave setup signal in the two dimensional model a lower more realistic current infragravity wave friction coefficient was required to achieve optimum performance due to the presence of significant reef and lagoon mean flows in the model which led to reduced setup across the reef the infragravity waves were found to propagate from the surf zone across the reef in a dominantly cross shore direction towards the shore but with substantial frictional damping the infragravity waves were strongly modulated also over the reef by tidal depth variations primarily due to the variability in frictional dissipation rates when the total water depth over the reef varied two mean wave driven circulation cells were observed in the study area with cross shore flow becoming more alongshore dominated before exiting the system via the two channels in the reef the results reveal that short waves dominated bottom stresses on the forereef and near the reef crest however inside the lagoon infragravity waves become increasingly dominant accounting up to 50 of the combined bottom stresses

simulation of tsunami hazards affecting the east cape region new zealand the east coast of new zealand is known for being exposed to a variety of tsunami sources both those arising from the nearby hikurangi subduction zone and its associated crustal faults and those arising from more distant parts of the pacific using numerical simulations with a parallelized computer model we assess the tsunami inundation hazard posed to the most populated coastal communities on the east coast of the east cape region new zealand which had not been evaluated before our tsunami inundation hazard study is based on severe but realistic scenario events from a selection of local and distant earthquake tsunami sources such modelling covers a gap in knowledge caused by the short historical record of tsunamis in this region covering 200 years and the sparse observations of historical tsunamis due to a largely rural population we identify that the worst flooding is often not associated with the first wave arrivals and that coastal oscillations can last a long time in distant events the modelling results allow us to determine typical characteristics of the pattern of flooding specific to an area this information is important for emergency planning and preparedness

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

signatures of natural catastrophic events and anthropogenic impact in an estuarine environment new zealand the sedimentary record of known natural catastrophic events and anthropogenic activity in an estuarine environment is assessed using sedimentological chemical and geochronological techniques shallow cores collected from intertidal and salt marsh sediments in ahuriri estuary hawke s bay reveal a variety of signatures of natural and human disturbance evidence for the 1931 hawke s bay earthquake which resulted in an uplift of one to two metres in the napier area is given by a change from silt to sand dominated sediment in the lower estuary which is consistent with a shift toward higher energy depositional conditions following uplift however based on physical properties of sediments the 1931 uplift event does not appear to have caused major changes in depositional conditions in the upper estuary similarly no changes were recorded at one site in the lower estuary which seems to represent an area of low energy depositional environment although the 1960 chilean tsunami resulted in structural damage in napier it did not produce any recognisable sedimentological and geochemical signature in the sedimentary record suggesting that the study sites were possibly beyond the limit of sedimentation of the tsunami post european settlement impact is mainly restricted to the lower estuary where increased concentrations of zn cr pb and cu are attributed to industrial discharges evidence of agricultural runoff is shown by an increase in cu concentrations within a fine grained depositional environment that is distal from industrial sources in the town of napier chemical data cl and s suggest a change in the depositional environment in the upper estuary due to increased freshwater influx and or decrease in seawater influence dating by 210pb suggests that this occurred around the middle part of the 19th century and might be attributed to river flooding in the region at that time

a modern analogue for plant colonization of palaeotsunami sands in cascadia british columbia canada the sediment stratigraphy of a modern analogue for pioneer plant colonization of palaeotsunami sands near tofino british columbia canada shows that a sand outcrop is continuous with a buried sand stratum deposited by tsunamis of the ad 1700 cascadia earthquake plants growing on the sand outcrop form a low marsh community that includes triglochin maritimum salicornia virginica spergularia canadensis puccinellia pumila and plantago maritima in contrast low marshes on muddy substrates include only carex lyngbyei although carex lyngbyei colonizes low marsh on mud it is restricted to middle marsh or higher elevation communities on sand with two way indicator species analysis twinspan and detrended corre spondence analysis dca plant cover abundance clearly distinguishes sandy from muddy low marsh a finding that suggests that particle size influences plant colonization twinspan and dca show that pollen spectra of the sandy marsh surface resemble fossil pollen of sediments that immediately over

the dynamics of infragravity wave transformation over a fringing reef a 3 week field study was conducted to investigate the dynamics of low frequency infragravity wave motions over a fringing reef at ningaloo reef western australia short period wave motions 0 04 0 2 hz were observed to dissipate on the reef crest beyond which infragravity wave motions 0 004 0 04 hz gradually dominated toward the lagoon however both the short waves and the infragravity waves were relatively small both 0 3 m on the reef flat owing to the shallow water depth 2 m the results revealed that the surf zone generation of free infragravity wave motions on the steep 1 20 fore reef slope was dominated by breakpoint forcing as opposed to shoaling bound waves which was also supported by detailed numerical simulations of the generation process this is consistent with theory suggesting the efficiency of the breakpoint forcing mechanism should be high in this steep slope regime shoreward propagating infragravity waves traveled across the reef but were damped by bottom friction dissipation however this was at a rate much smaller than experienced by the residual short waves with these rates of frictional dissipation also strongly dependent on the water depth over the reef the infragravity wave heights increased at higher water levels and hence were strongly modulated by the tide due to the strong dissipation of infragravity waves over this wide and shallow reef that is hydraulically rough any seaward propagating infragravity waves that reflected at the shoreline were small leading to the dominance of progressive shoreward propagating infragravity wave motions throughout the reef and lagoon

sediments deposited by the 2004 indian ocean tsunami along the malaysia thailand peninsula stratigraphy grain size distribution and foraminiferal assemblages of pre tsunami and tsunami sediment from the indian ocean tsunami at five sites along the malaysia thailand peninsula were analyzed to gain information on tsunami sediment source and deposition style between three and five stratigraphic units were identified at each site and contained between one and three fining upward sequences reflecting waning flow or pre backwash deposition coarser sand layers reflecting uprush high energy flow separated the fining upward sequences with the exception of one site sungai burong which contained a coarsening upward sequence all contacts between the pre tsunami and tsunami sediment were sharp or erosional medium and coarse sand dominated all of the tsunami sediment deposits and often contained shell fragments foraminiferal assemblages were able to differentiate pre tsunami sediment from tsunami sediment where no lithological or grain size distribution change was evident between two and four foraminiferal zones were identified at each of the five sites and provided estimates of sediment source and wave characteristics

seismic recurrence intervals and timing of aseismic subduction inferred from emerged corals and reefs of the central vanuatu new hebrides frontal arc the recognition and dating of corals that have been killed by tectonic uplift allow us to date paleoseismic uplifts in the vanuatu island arc we recognize corals that record paleouplifts by their similarity to those known to have died during contemporary sudden uplifts and date them 1 by counting annual coral growth bands only if part of the coral is alive at the time of collection or 2 by newly developed techniques for obtaining 230 th ages by mass spectrometry the mass spectrometric method produces isotopic ages with precisions of 3 to 9 years 2 in the 0 1000 years b p time range the 230 th ages in this time range appear to be accurate samples whose ages are known by counting coral growth bands give 230 th ages that are indistinguishable from their growth band ages by dividing the average increment of uplift for the latest holocene uplifts by the mean holocene uplift rate we can estimate average seismic uplift recurrence intervals for the past 6000 years the results for each of four central vanuatu arc segments are 1 north santo emerged 1 2 m in 1866 a d and 0 6 m 107 years later in 1973 a d the average coseismic uplift of 0 9 m and mean holocene uplift rate of 4 3 mm yr 1 suggest a longer recurrence interval of 212 years 2 south santo emerged 0 29 m in 1946 and 0 26 m 19 years later in 1965 including the related 1971 event here the mean holocene uplift rate is 5 5 mm yr 1 the uplift data suggest a longer average recurrence interval of about 51 years 3 north malekula emerged 1 23 m near 1729 a d and 1 05 m 236 years later in 1965 the mean holocene uplift rate of 2 7 mm yr 1 and mean coseismic uplift of 1 14 m for dated events suggest a longer recurrence interval of 422 years 4 part of southernmost malekula has uplifted continuously or episodically by about 0 35 m from about 1957 until at least mid 1983 a d the maximum uplift of 2 7 mm yr 1 occurs near a nest of small earthquakes both the earthquakes and rapid uplift suggest that interplate slip beneath south malekula may be continuous rather than episodic episodes of 0 35 m uplift would have to recur every 130 years to maintain the 2 7 mm yr 1 uplift rate in contrast we find no evidence of interseismic vertical movements for the other three blocks the most reasonable interpretation of these results is that the seismic recurrence intervals and processes for accommodation of slip are quite different on adjacent arc segments we have used the most widely accepted moment magnitude relationship to evaluate the accumulated seismic slip caused by large earthquakes occurring since 1920 in all four arc segments this analysis suggests that the seismically radiated moments account for less than one third to one tenth of the slip associated with plate convergence the similarity between the paleoseismic record of uplifts and the contemporary record of coseismic uplifts suggests that this analysis can be generalized to times before 1920 for the northern three segments of central vanuatu aseismic slip probably occurs in the same years as large earthquakes because the contemporary coral record records uplifts only in years having large historic earthquakes this suggests that aseismic slip is not continuous and does not occur at rates which vary slowly over the course of the earthquake cycle the south santo segment may have the highest proportion of seismic slip because the mean recurrence interval of 51 years is shortest and the mean holocene uplift rate of at least 5 5 mm yr 1 is the fastest

the combined influence of hydrodynamic forcing and calcification on the spatial distribution of alkalinity in a coral reef system 1 we investigated the influence of hydrodynamic forcing waves tides alongshore currents and winds and net calcification by coral reef organisms on the spatial distribution of total alkalinity ta in a fringing reef system through a combination of field measurements and numerical modeling a field experiment was conducted over 10 days in coral bay ningaloo reef western australia during which we measured wave heights currents and tides as well as the spatial distribution of ta across the fore reef reef crest and lagoon we used observed changes in ta on the adjacent reef flat along with synoptic measurements of cross reef transport to estimate in situ rates of net calcification gcv using a control volume approach based on the gcv estimated we simulated light driven diurnal variations in benthic net calcification within a three dimensional ocean circulation model roms regional ocean modeling system by coupling roms with a spectral wave model simulating waves nearshore we were able to simulate currents within coral bay reef lagoon system that were in good agreement with the field observations and demonstrate that circulation with the system was wave dominated both the field measurements and numerical model output confirmed that both residence time r and ta varied primarily with offshore wave heights and location within the bay however variations in ta were also affected by the nonlinear interaction between rates of net calcification that varied as a function of diurnally changing light and water residence time that varied as a function of offshore wave heights

hydrodynamic implications of textural trends in sand deposits of the 2004 tsunami in sri lanka abstract field observations and sediment samples at a coastal plain setting in southeastern sri lanka were used to document the erosional and depositional impacts of the 2004 indian ocean tsunami and to interpret the hydrodynamic processes that produced an extensive sand sheet deposit tsunami deposit thicknesses ranged from 6 to 22 cm with thickness being controlled partly by antecedent topography the deposit was composed of coarse to medium sand organized into plane parallel laminae and a few laminasets vertical textural trends showed an overall but non systematic upward fining and upward thinning of depositional units with an upward increase in heavy mineral laminations at some locations repeated patterns in the vertical textural trends upward fining upward coarsening uniform were used to subdivide and correlate the deposit into five hydro textural stratigraphic units the depositional units were linked to hydrodynamic processes and upcurrent conditions such as rates of sediment supply and composition of the sediment sources vertical changes in grain size distributions recorded the depositional phases associated with flow acceleration initial unsteady pulsating flow relatively stable and uniform flow flow deceleration slack water and return flow or flow redirection study results suggest that vertical textural trends from multiple cross shore sections can be used to interpret complex tsunami flow histories but at the location examined interpretation of the lateral textural trends did not provide a basis for identifying the correct sediment transport pathways because flow near the landward boundary was multidirectional

recognition of diagnostic criteria for recent and paleo tsunami sediments from sri lanka uncontaminated sediment from the december 26 2004 tsunami in southern sri lanka was collected from a previously empty arrack bottle stacked in a plastic case at an elevation of about 5 m above mean sea level and from several other localities the sediments were analysed for grain size distribution sediment petrography and microfossil assemblages and were compared with storm surge sediment and nearshore sediment the undiluted tsunami sediment is a brownish silty fine sand it is characterized by a particular grain size distribution and an assemblage of planktonic benthic microfossils consisting of foraminifera radiolarians and spicules storm surge and nearshore sediments are better sorted have fewer microfossils more rounded quartz grains and a higher proportion of heavy minerals influenced by references in sri lankan ancient texts to past tsunamis we searched for paleo tsunami sediments in potential locations such as the coastal depressions in borehole samples and well cuttings from soil profiles in the coastal village of peraliya we were able to recognize two paleo tsunami horizons at 30 and 75 cm below the present ground surface each consisting of brownish silty fine sand that remarkably resembled the recently deposited undiluted tsunami sediment

kuwae 1425 a d the forgotten caldera in vanuatu tongoa and epi islands once formed part of a larger landmass kuwae which was partly destroyed during a cataclysmic seismo volcanic event that is recorded in local folklore it led to the formation of a 12 kmlong and 6 km wide oval shaped submarine caldera with two distinct basins and a total area of 60 km2 at the level of the rim the age ofthis eniption 1420 1430 a d and the structure of the related collapse are discussed and a composite log 143 m of the pyroclastics surrounding the caldera is presented they comprise thick hydromagmatic deposits belonging to a terminal hydromagmatic phase of the pre caldera edifice which grade upwards into two major sequences of pyroclastic flow deposits clearly related to the caldera event collapse near the caldera edge was at least in the range 650 to 950 m and may have been as much as 800 to 1100 m the volume of rocks engulfed during the caldera formation is 32 39 km3 suggesting the same volume of magma was erupted even if two coalescent collapse structures were formed it is worth noting that the kuwae caldera is not a reactivated structure but the result of a single event of short duration which occurred in the first half of the fifteenth century this event is one of the seven biggest caldera forming events during the last 10 000 years and is comparable with the santorini minoan eruption and the crater lake eruption

using magnetic fabric to reconstruct the dynamics of tsunami deposition on the sendai plain japan the 2011 tohoku oki tsunami abstract the magnetic fabric and grain size of sand deposits emplaced during the 2011 tohoku oki tsunami were studied in five trenches along a 1800 m long shore normal transect on the sendai plain as well as in a near shore sedimentary infill of a scour depression the magnetic susceptibility in all deposits is due to ferromagnetic minerals mainly magnetite making the anisotropy of magnetic susceptibility magnetic fabric suitable for fabric analyses the dominant magnetic fabric is planar in all trenches and stronger in finer grained inland deposits than in the coarser sediments this planar fabric is related to tractive shearing of the bedload basal portion of the tsunami flow that led to the deposition of traction carpet layers among the various fabric parameters used for this study the vertical evolution of the shape factor q of the magnetic ellipsoid in each trench follows the evolution of the magnetic lineation l and foliation f these parameters provide information on the hydrodynamic energy flow speed fluctuations during the emplacement of the tsunami deposit for the most proximal deposits characterized by well sorted reworked beach sand with minor fluctuations in grain size distribution the magnetic fabric is sensitive to hydrodynamic energy variations during sedimentation reconstruction of tsunami flow orientation in the sediments based on the orientation of the mean k max calculated for each trench appears to be unambiguous only for the sandy infills of small topographic depressions the variations in flow direction indicators elsewhere could be related to local variation of the flow and to micro topographic effects these findings are encouraging for the use of the magnetic fabric proxy in the study of paleotsunami deposits

the influence of coral reefs and climate change on wave driven flooding of tropical coastlines a numerical model xbeach calibrated and validated on field data collected at roi namur island on kwajalein atoll in the republic of marshall islands was used to examine the effects of different coral reef characteristics on potential coastal hazards caused by wave driven flooding and how these effects may be altered by projected climate change the results presented herein suggest that coasts fronted by relatively narrow reefs with steep fore reef slopes 1 10 and steeper and deeper smoother reef flats are expected to experience the highest wave runup wave runup increases for higher water levels sea level rise higher waves and lower bed roughness coral degradation which are all expected effects of climate change rising sea levels and climate change will therefore have a significant negative impact on the ability of coral reefs to mitigate the effects of coastal hazards in the future

two dimensional modelling of wave dynamics and wave forces on fringing coral reefs abstract two dimensional numerical modelling of swell wave dynamics on idealized fringing reefs is performed using swan covering a wide range of bathymetries climate forcing conditions and water depths over the reefs the results illustrate the impact of reef geometry and bathymetry coral species and sea level rise on key hydrodynamic parameters on the reef and on forces on corals the modelling demonstrates that one dimensional models underestimate the wave action on the reef flat wide short reefs and narrow long reefs have similar wave heights at the centre of the reef flat for a given reef length the wave height first decreases with increasing reef width then increases to a local maximum when reef width is approximately equal to the reef length and then decreases for further increases in width this pattern is a result of combined dissipation and refraction processes which combine to lead to different zones of cross reef wave transformation provided that a reef retains its hydrodynamic functions in breaking and refracting the waves sea level rise enhances the wave heights and wave orbital velocities on the reef flat if vertical coral growth does not keep pace with sea level rise loss of the hydrodynamic functions of the reef may occur on deeper reefs and result in a reduction of near bed velocities with sea level rise hydrodynamic forces on corals vary by coral species and slr changes the magnitude of the forces on different species in different ways which may lead to less favourable conditions for certain coral species for long period swell the intermediate size corals are drag dominated and behave similarly to branching corals whereas for short period swell their behavior is similar to that of the inertia dominated massive corals for intermediate corals different responses to slr may therefore be expected for different overall regional wave climates over time this process may contribute to changes in the structural complexity of reefs the influence of sea level rise on the forces on corals on the reef flat is different under swell and cyclonic wind conditions since wind influences wave period in the latter case

coral mortality increases wave energy reaching shores protected by reef flats examples from the seychelles in the granitic seychelles many shores and beaches are fringed by coral reef flats which provide protection to shores from erosion by waves the surfaces of these reef flats support a complex ecology about 10 years ago their seaward zones were extensively covered by a rich coral growth which reached approximately to mean low water level but in 1998 this was largely killed by seawater warming the resulting large expanses of dead coral skeletons in these locations are now disintegrating and much of the subsequent modest recovery by new coral recruitment was set back by further mortalities a mathematical model of wave energy reaching shorelines protected by coral reef flats has been applied to 14 seychelles reefs it is derived from equations which predict 1 the raised water level or wave set up on reef flats resulting from wave breaking which depends upon offshore wave height and period depth of still water over the reef flat and the reef crest profile and 2 the decay of energy from reef edge to shoreline that is affected by width of reef flat surface roughness sea level rise and pseudo sea level rise created by increased depth resulting from disintegration of coral colonies the model treats each reef as one entity but because biota and zonation on reef flats are not homogenous all reefs are divided into four zones in each cover by both living and dead biota was estimated for calculation of parameters and then averaged to obtain input data for the model all possible biological factors were taken into account such as the ability of seagrass beds to grow upwards to match expected sea level rise reduction in height of the reef flat in relation to sea level as zones of dead corals decay and the observed rounding of reef crests as erosion removes corals from those areas estimates were also made of all these factors for a time approximately a decade ago representing a time before the mass coral mortality and for approximately a decade in the future when the observed rapid state of dead coral colony disintegration is assumed to have reached an end point results of increased energy over the past decade explain observations of erosion in some sites in the seychelles most importantly it is estimated that the rise in energy reaching shores protected by fringing reefs will now accelerate more rapidly such that the increase expected over the next decade will be approximately double than that seen over the past decade c 2005 elsevier ltd all rights reserved

chemical signatures of palaeotsunamis a forgotten proxy article i nfo article history a range of diagnostic criteria are required to help identify palaeotsunami deposits although chemical signatures have long been used as indicators of palaeosalinity in sedimentary sequences their use in the studies of palaeotsunami deposits is rarely applied and is yet to be widely recognised the chemical composition of interstitial water in coastal ponds and sedimentary sequences in coastal marshes and lagoons has been used successfullyasanindicatoroftsunamiinundation chemicalsignaturescanalsoprovidecluesaboutthelandward limit of runup of a tsunami beyond the area of sediment deposition like most palaeotsunami proxies however the preservation of chemical signatures varies with environmental conditions

tsunamis in the new zealand archaeological record abstract historical and geological records both indicate tsunami inundation of new zealand in the 700 years since the first human settlement in addition maori oral traditions refer to unusual waves that might have been tsunami waves although the accounts are open to other interpretations tsunami evidence has rarely been proposed from archaeological sites primarily because of a limited understanding of the requisite evidence and environmental context we list a criteria suggesting possible tsunami inundation of archaeological sites based upon geoarchaeological data and use them in a case study from the archaic maori occupation site at wairau bar the list is possibly incomplete but indicates that archaeological investigations can gain from assessments of changing environmental conditions through time at any individual site our intention is not to prove tsunami inundation rather it is to point to archaeological sites as possible sources of information we highlight the potential of the wairau bar site for further investigation

temporal and spatial variability in the flow and dispersal of suspended sediment on a fringing reef flat molokai hawaii abstract a multi year study was conducted on a shallow fringing reef flat on molokai hawaii to determine the temporal and spatial dispersal patterns of terrigenous suspended sediment during this study trade wind conditions existed for the majority of the year on the reef flat the trade wind conditions produced strong currents and resuspended moderate amounts of sediment on the reef flat on a daily basis during the year of study resulting in an overwhelming contribution to the total sediment flux the magnitude and direction of the trade winds relative to the orientation of the coastline the shallow relief and broad morphology and tidal elevation provided the primary control of the physical processes that resuspended and transported sediment on the reef flat over the period of record spatial data indicate that much of the terrigenous sediment resuspended on the reef flat is transported predominantly alongshore and is confined to the inner to mid reef flat evidence for the limited across shore mixing and transport is provided by the dominantly alongshore wind driven currents during trade wind conditions and the well defined across shore gradient in percentage calcium carbonate of the suspended sediment regions of slightly offshore suspended sediment transport along the reef flat can be attributed to the circulation pattern set up by the interaction between the trade winds coastal morphology and anthropogenic coastal structures i e fish ponds and wharf the regions in which sediment were seen to move offshore provide the strongest link between the sediment dynamics on reef flat and fore reef and qualitatively appears to be correlated with low coral coverage on the fore reef

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

extreme wave deposits on the pacific coast of mexico tsunamis or storms a multi proxy approach abstract historical and instrumental data show that the pacific coast of mexico has been exposed to destructive tsunamis over at least the past 500 years this coast is also affected by hurricanes generated in the eastern pacific the great 1985 mexico earthquake and its aftershock generated tsunamis that affected the ixtapa zihuatanejo and michoacan coast the purpose of our study was two fold a to determine whether storm and tsunami deposits could be distinguished and b whether tsunami deposits from historical events are preserved in the tropical environments of the ixtapa zihuatanejo coast two anomalous sand units in the ixtapa estuary are interpreted to be the result of high energy marine inundation events that occurred in the last century several lines of evidence using a multi proxy approach historical studies interviews with local witnesses geomorphological and geological surveys coring and trenching laboratory analyses including grain size micropaleontology geochemistry magnetic susceptibility and radiometric dating and numerical modeling indicate the occurrence of two tsunamis that we link to local events the 21st september 1985 mexico and possibly the 14th march 1979 petatlan earthquakes we thereby provide the first onshore geological evidence of historical tsunamis on the pacific coast of mexico

historical nankai suruga megathrust earthquakes recorded by tsunami and terrestrial mass movement deposits on the shirasuka coastal lowlands shizuoka prefecture japan geological investigations of coastal sediment sequences play a key role in verifying earthquake and tsunami characteristics inferred from historical records in this paper we present a multi proxy investigation of a coastal lowland site facing the nankai suruga megathrust and appraise evidence for tsunamis and earthquake triggered terrestrial mass movements occurring over the last 800 years combining a high resolution chronology with x ray computed tomography and analyses of particle size diatoms pollen non pollen palynomorphs and aerial photographs we present the most compelling geological evidence of the 1361 ce koan also known as shohei tsunami reported to date from any site along the megathrust this finding is consistent with either of two recent hypotheses a single larger rupture of both the nankai and tnankai regions or two smaller ruptures separated by a few days enhancing the site chronology using bayesian age modelling we verify evidence for inundation during the 1498 ce mei tsunami while previous investigations identified evidence for historically recorded tsunamis in 1605 1707 and 1854 ce and a storm surge in 1680 or 1699 ce we encountered a thick sand layer rather than discrete extreme wave deposits in this interval the overprinting of evidence highlights the potential for geological records to underestimate the frequency of these events a terrestrial mass movement also deposited a sand layer at the site radionuclide dating and aerial photographs provide independent confirmation that this may have been triggered by intense shaking in 1944 ce during the most recent great nankai suruga megathrust earthquake

lagoon subsidence and tsunami on the west coast of new zealand abstract sediment core and trench data from a coastal lagoon on the west coast of the south island new zealand are used to investigate evidence for co seismic subsidence and associated tsunami inundation physical data are used to document a salt marsh soil buried 80 cm below the modern sediment surface that is locally covered by a gravelly sand bed the sediment record also contains geochemical and biological diatom and foram evidence for abrupt changes in salinity of lagoon waters that link to subsidence tsunami flooding and to the open versus closed state of the lagoon tidal entrance at the local scale these relationships allow for separation of tsunami evidence from other agents of environmental change in the lagoon we also propose a conceptual connection between these local changes and regional drivers of landscape development most notably major earthquakes and resultant pulses in sediment supply to the coast

nonhydrostatic and surfbeat model predictions of extreme wave run up in fringing reef environments abstract the accurate prediction of extreme wave run up is important for effective coastal engineering design and coastal hazard management while run up processes on open sandy coasts have been reasonably well studied very few studies have focused on understanding and predicting wave run up at coral reef fronted coastlines this paper applies the short wave resolving nonhydrostatic xb nh and short wave averaged surfbeat xb sb modes of the xbeach numerical model to validate run up using data from two 1d alongshore uniform fringing reef profiles without roughness elements with two objectives i to provide insight into the physical processes governing run up in such environments and ii to evaluate the performance of both modes in accurately predicting run up over a wide range of conditions xbeach was calibrated by optimizing the maximum wave steepness parameter maxbrsteep in xb nh and the dissipation coefficient alpha in xb sb using the first dataset and then applied to the second dataset for validation xb nh and xb sb predictions of extreme wave run up rmax and r2 and its components infragravity and sea swell band swash sig and sss and shoreline setup were compared to observations xb nh more accurately simulated wave transformation but under predicted shoreline setup due to its exclusion of parameterized wave roller dynamics xb sb under predicted sea swell band swash but overestimated shoreline setup due to an over prediction of wave heights on the reef flat run up swash spectra were dominated by infragravity motions allowing the short wave but not wave group averaged model xb sb to perform comparably well to its more complete short wave resolving xb nh counterpart despite their respective limitations both modes were able to accurately predict rmax and r2

sheet gravel evidence for a late holocene tsunami run up on beach dunes great barrier island new zealand abstract a semi continuous sheet of granule to cobble size clasts forms a distinctive deposit on sand dunes located on a coastal barrier in whangapoua bay great barrier island new zealand the gravel sheet extends from the toe of the foredune to 14 3 m above mean sea level and 200 m landward from the beach clasts are rounded to sub rounded and comprise lithologies consistent with local bedrock terrestrial sources for the gravel are considered highly unlikely due to the isolation of the dunes from hillslopes and streams the only source for the clasts is the nearshore to inner shelf of whangapoua bay where gravel sediments have been previously documented the mechanism for transport of the gravel is unlikely to be storm surge due to the elevation of the deposit maximum recorded storm surge on this coast is 0 8 m above mean high water spring tide aeolian processes are also discounted due to the size of clasts and the elevation at which they occur tsunami is therefore considered the most probable mechanism for gravel transport minimum run up height of the tsunami was 14 3 m based on maximum elevation of gravel deposits optical ages on dune sands beneath and covering the gravel allow age bracketing to 0 4 7 ka within this time frame numerous documented regional seismic and volcanic events could have generated the tsunami notably submarine volcanism along the southern kermadec arc to the east southeast of great barrier island where large magnitude events are documented for the late holocene radiocarbon ages on shell from maori middens that appear to have been reworked by tsunami run up constrain the age of this event to post ca 1400 ad regardless of the precise age of this event the well preserved nature of the whangapoua gravel deposit provides for an improved understanding of the high degree of spatial variability in tsunami run up

predecessors to the 2009 south pacific tsunami in the wallis and futuna archipelago abstract multi proxy studies of trench sediments from futuna island in the wallis and futuna archipelago have produced a record of two palaeotsunamis dated to around 1860 2000 bp and c 470 bp one of the most useful proxies in this study has been the archaeological data associated with occupations that immediately underlie the deposits associated with both palaeotsunamis the reworking of the archaeological material into the palaeotsunami deposits and the additional chronological control provided by artefacts have added value to interpretations based upon more conventional earth science proxies the identification of tsunamigenic sources for these events is tentative and based upon known potential sources based upon a comparison between the effects of the 2009 south pacific tsunami and those recorded in the trenches event 1 1860 2000 bp appears most likely to be associated with a large tsunami sourced from the tonga kermadec trench region there are only rare contemporaneous events reported from around the region although this appears to be largely due to a lack of similar research as opposed to a lack of evidence event 2 c 470 bp is markedly larger than event 1 with sedimentary evidence indicating significant inland inundation and runup around the entire island there are several lines of evidence for a contemporaneous event in the south pacific around 470 bp although much of this needs further verification determining a source for this event is problematic because it must take in to account the regional signal and the significant impacts recorded on futuna we propose that the source for this younger event was either a larger tonga kermadec trench related earthquake or the kuwae caldera collapse in 1452 1453 ad we recognise that as further research is carried out in the pacific we will greatly improve our abilities to identify past sources and the magnitude and frequency of past events from these areas this can only serve to improve our understanding of the regional risk from tsunamis

analysis of environmental controls on tsunami deposit texture abstract tsunamis transport large amounts of sediment and can leave recognisable signatures in the landscape the form and composition of onshore tsunami deposits are a function of wave dynamics sediment availability and characteristics of the local environment the latter of which also partially controls preservation of the deposit this research reviews these relationships in a global context and assesses the connection between tsunami deposit particle size and four controlling parameters climate temperature and rainfall density of tsunami sediments degree of coastal protection and distance between tsunami source and sediment deposition an international dataset of tsunami deposit locations and texture was compiled from published literature and existing databases values for environmental variables were calculated for each location from global datasets of temperature rainfall coastline shape and tsunami source locations spearman s rank order correlation principal component analysis pca and hierarchical cluster analysis ca were used to analyse relationships between these variables pca results show an inverse relationship between particle size and sediment density climate variables and distance from source ca results support this suggesting a cluster structure controlled primarily by particle size and secondly by climate and sediment density these relationships can be explained by the influence of the environment on antecedent morphology and the composition of sediments available for tsunami transport

the tectonic deformation of quaternary deposits within the kleszczow graben central poland abstract three well recognizable structural stages can be observed within the kleszczow graben central poland they are divided by angular discordances the valachian stage consists of strongly folded and faulted deposits of miocene age the belchatow stage consists both of pliocene and quaternary deposits the last stage dates back to the beginning of the drenthe warthe interglacial the tectonic origin or quaternary deformation folding of the belchatovian age seems rather unquestionable in the uppermost structural stage only some glaciotectonic deformations can be observed

the characteristics and dynamics of wave driven flow across a platform coral reef in the red sea current dynamics across a platform reef in the red sea near jeddah saudi arabia are examined using 18 months of current profile pressure surface wave and wind observations the platform reef is 700 m long 200 m across with spatial and temporal variations in water depth over the reef ranging from 0 6 to 1 6 m surface waves breaking at the seaward edge of the reef cause a 2 10 cm setup of sea level that drives cross reef currents of 5 20 cm s 1 bottom stress is a significant component of the wave setup balance in the surf zone over the reef flat where waves are not breaking the cross reef pressure gradient associated with wave setup is balanced by bottom stress the quadratic drag coefficient for the depth average flow decreases with increasing water depth from cda 0 17 in 0 4 m of water to cda 0 03 in 1 2 m of water the observed dependence of the drag coefficient on water depth is consistent with open channel flow theory and a hydrodynamic roughness of zo 0 06 m a simple one dimensional model driven by incident surface waves and wind stress accurately reproduces the observed depth averaged cross reef currents and a portion of the weaker along reef currents over the focus reef and two other red sea platform reefs the model indicates the cross reef current is wave forced and the along reef current is partially wind forced

dating tsunami deposits present knowledge and challenges abstract dating approaches for fine sediment tsunami deposits can be divided into two categories 1 dating directly using materials from within a tsunami deposit and 2 dating indirectly using materials from above and below it for the former optically stimulated luminescence osl dating has a possible advantage in that is can directly date the burial age of sediments laid down by a tsunami however because of methodological limitations osl dating cannot always provide a reliable age although 14c and u th dating of reworked material from within a tsunami deposit are possible means of determining the age of the event the results merely represent a maximum age of deposition for these reasons dating is commonly achieved indirectly from 14c dates taken from samples in sections immediately above and below a tsunami deposit however indirectly dated results do not provide a precise timing of the event therefore there are distinct limitations in the ability to obtain high precision dating of past tsunamis recent methodological developments including the application of bayesian statistical analysis to radiocarbon dating results and the selection of appropriate dating materials has significantly improved the accuracy of age determination by reducing errors this review presents several methodological improvements that have enhanced tsunami deposit age estimation the most important points for a more precise tsunami age estimation are the numbers of 14c samples dated coupled with the use of bayesian statistical analysis these points are applicable not only to tsunami deposits but also to many other past geohazard events

distinguishing tsunami and storm deposits an example from martinhal sw portugal abstract geological identification of past tsunamis is important for risk assessment studies especially in areas where the historical record is limited or absent the main problem when using the geological evidence is to distinguish between tsunami and storm deposits both are high energy events that may leave marine traces in coastal stratigraphic sequences at martinhal sw portugal both storm surge and tsunami deposits are present at the same site within a single stratigraphic sequence which makes it suitable to study the differences between them excluding variations caused by local factors the tsunami associated with the lisbon earthquake of november 1st 1755 ad had a major impact on the geomorphology and sedimentology of martinhal it breached the barrier and laid down an extensive sheet of sand as described in eyewitness reports besides the tsunami deposit the stratigraphy of martinhal also displays evidence for storm surges that have breached and overtopped the barrier flooding the lowland and leaving sand layers both marine derived flood deposits show similar grain size characteristics and distinctive marine foraminifera the most important differences are the rip up clasts and boulders exclusively found in the tsunami deposit and the landward extent of the tsunami deposit that everywhere exceeds that of the storm deposits identification of both depositional units was only possible using a collection of different data and extensive stratigraphical information from cores as well as trenches

seismic signals in coastal dune systems abstract coastal dune ridge systems throughout the world form initially in response to phases of abundant sand supply and yet researchers rarely consider the importance of seismic related activity to dune formation or destruction new zealand examples of seismic related coastal dune formation and their occasional remobilisation are discussed pulses of sand sized sediment produced by large earthquakes and transported to the coast by geomorphic processes can generate new dune ridges tsunami inundation can modify existing dunes producing features such as relict dune pedestals landward sand sheets hummocky topography and parabolic dunes the case is put forward for the need to consider evidence for catastrophic events in coastal dune systems particularly when working in tectonically active areas of the world recognition of some of the effects of seismic related processes on coastal dunes however does not mean that these are easily identified in the field or even present in the existing landscape it does however mean that they should not be ignored

distribution and sedimentary characteristics of tsunami deposits along the cascadia margin of western north america abstract tsunami deposits have been found at more than 60 sites along the cascadia margin of western north america and here we review and synthesize their distribution and sedimentary characteristics based on the published record cascadia tsunami deposits are best preserved and most easily identified in low energy coastal environments such as tidal marshes back barrier marshes and coastal lakes where they occur as anomalous layers of sand within peat and mud they extend up to a kilometer inland in open coastal settings and several kilometers up river valleys they are distinguished from other sediments by a combination of sedimentary character and stratigraphic context recurrence intervals range from 300 1000 years with an average of 500 600 years the tsunami deposits have been used to help evaluate and mitigate tsunami hazards in cascadia they show that the cascadia subduction zone is prone to great earthquakes that generate large tsunamis the inclusion of tsunami deposits on inundation maps used in conjunction with results from inundation models allows a more accurate assessment of areas subject to tsunami inundation the application of sediment transport models can help estimate tsunami flow velocity and wave height parameters which are necessary to help establish evacuation routes and plan development in tsunami prone areas

the holocene storegga slide tsunami in the united kingdom all currently known sites in the united kingdom with evidence for the holocene storegga slide tsunami are described information on the altitude distribution stratigraphical context age particle size profile and microfossil characteristics of the deposits is presented the tsunami involved a greater area than previously described reaching a coastline over 600 km long the ubiquitous sand layer which forms the main deposit associated with the event is shown to exhibit a consistent morphology and a particle size profile marked by fining upwards sequences an analysis of new and previously published radiocarbon dates indicates that from evidence in the united kingdom the event took place sometime around 7100 radiocarbon years bp 7900 calibrated years bp a new isobase model for mainland scotland and adjacent areas providing a preliminary estimate of land uplift since the tsunami is presented the model estimates contemporary sea surface level offshore at 14 m below the present day mean high water spring tides tsunami sediment run up is greatest in inlets where it reaches at least 25 m on shetland and at least 5 m along the mainland coastline to the south and run up of the tsunami would have exceeded these values the tsunami sediments identified here are considered particularly valuable as a synchronous marker horizon

sea level rise will drive divergent sediment transport patterns on fore reefs and reef flats potentially causing erosion on atoll islands these data files and matlab scripts reproduce the model data and figures as published in bramante et al in prep modeling the impacts of a changing climate on cross shore sediment transport kwajalein atoll marshall islands

submarine silicic volcanism of the healy caldera southern kermadec arc sw pacific i volcanology and eruption mechanisms the submarine healy volcano southern kermadec arc with a 2 2 5 km wide caldera is pervasively mantled with highly vesicular silicic pumice within a water depth of 1 150 1 800 m pumices comprise type 1 white light grey pumice with 30 mm vesicles and weak moderate foliation type 2 grey pumice with millimetre scale laminae flow banded foliation including stretched vesicles 55 mm in length and a minor finely vesicular type 3 pumice all types are sparsely porphyritic with undevitrified glassy groundmass 68 70 sio2 which is microlite and lithic free coexisting pyroxenes yield magma temperatures of 950 c pumice density is 0 5 g cm 3 and vesicularity is 78 83 vesicle size distributions for types 1 and 2 pumice range from 20 m to 20 mm with a strong power law relation with d 2 5 0 4 for vesicles 9 mpa will limit vesicularity to less than the observed 78 83 whereas pressure 6 mpa require a more shallower reconstruction of the edifice and larger volume syn eruptive collapse uniformly high vesicularity is interpreted as evidence of insulation within an eruption column comprising steam and hot pyroclasts most pyroclasts cool condensing and ingesting water into steam inflated vesicles and then sink progression into pyroclastic mode would expand the eruption column displace ambient water reduce the hydrostatic load and further promote vesiculation and fragmentation pyroclasts within the column would quench at these reduced pressures we argue that healy eruptions deeper than 1 000 m cannot be pyroclastic volumes for the lower and upper bounds of edifice size are 2 36 and 3 58 km3 respectively but do not account for intra caldera pumice fill these volumes are considered to be predominantly primary eruption output as shown by a dearth of accessory lithics in all pumice yielding at an average 81 vesicularity eruptive pumice volumes of between 10 and 15 km3 some pyroclasts may have risen to the sea surface and be a correlative of the sea rafted loisels pumice the latter occurs in some new zealand holocene beach sequences and has a estimated age of 590 80 calendar years

mass transfer limitation of nutrient uptake by a wave dominated reef flat community maximum rates of phosphate nitrate and ammonium uptake by a reef flat community were estimated from rates of frictional dissipation that were calculated from the attenuation of waves propagating over the kaneohe bay barrier reef flat time averaged flow speeds across the entire study area ranged from 0 08 to 0 22 m s 21 observed decreases in wave energy fluxes and near bottom orbital velocities gave a mean estimate for the bottom friction coefficient cf of 0 22 6 0 03 friction coefficients were used to estimate nutrient mass transfer coefficients of 5 9md 21 for phosphate and 9 16 m d 21 for ammonium and nitrate wave heights offshore of kaneohe bay were also used to estimate an annual phosphate mass transfer coefficient of 8 6 2md that was determined from measured changes in phosphate concentrations across the reef flat we conclude that rates of phosphate uptake by the kaneohe bay barrier reef flat community are occurring near the limits of mass transfer net primary production is a major pathway by which mass and energy flow into coral reef ecosystems the uptake of dissolved nutrients is often the rate limiting step for net pri mary production in marine ecosystems thus a knowledge of the kinetics of nutrient uptake by coral reef communities is necessary for assessing how nutrient loading rates change in response to natural or anthropogenic increases in nutrient concentrations bilger and atkinson 1992 proposed that nutrient uptake by shallow reef communities was limited by mass transfer the physical transfer of nutrients across con centration boundary layers covering the surfaces of reef au totrophs these authors used mass transfer correlations for rough surfaces taken from the engineering literature to cor relate maximum rates of nutrient uptake with the frictional characteristics of experimental reef communities subse quent studies demonstrated the ability of such mass transfer correlations to predict nutrient uptake kinetics for experi mental reef communities within closed recirculating flumes atkinson and bilger 1992 bilger and atkinson 1995 thomas and atkinson 1997 and a large experimental me socosm atkinson et al 2001 the results of these studies made it clear that shallow water reef communities are ca pable of taking up nutrients from the water column at rates that are limited by mass transfer however it had not yet been demonstrated whether in situ rates of nutrient uptake

geochemical and petrographical characteristics of a domed bog nova scotia a modern analogue for temperate coal deposits a freshwater domed bog in nova scotia canada was investigated for its petrographic mineralogical and geochemical characteristics three cores were taken from the lagg zone margin and centre to examine different stages of evolution in a fen to domed bog sequence based on this study a model was developed which shows the relationship between factors controlling peat geochemistry and petrography all of them being dependent on trophic conditions the bog may represent a modern analogue for temperate coal deposits and thus can be used to help understand spatial variability within coal beds rheotrophic conditions in the early stages of mire development result in the formation of high ash highly humified carex dominated peat while the evolution toward ombrotrophic conditions is reflected in a progressive replacement by low ash and well preserved sphagnum dominated peat the associated decrease in ph reflects a decrease of groundwater influence which is also supported by the mineralogical assemblage and petrographic data decrease in reflectance and change in maceral composition except for cl br i and se which are associated with the organic fraction variations in elemental composition can be explained in terms of mineral matter abundance i e decrease upward and with increasing distance from the margin sea spray is the most probable origin for halogen enrichment in the peat

new multibeam mapping and geochemistry of the 30 35 s sector and overview of southern kermadec arc volcanism new multibeam mapping and whole rock geochemistry establish the first order definition of the modem submarine kermadec arc between 30 degrees and 35 degrees s twenty two volcanoes with basal diameters 5 km are newly discovered or fully mapped for the first time giggenbacb macauley havre haungaroa kuiwai ngatoroirangi sonne kibblewhite and yokosuka for each large volcano edifice morphology and structure surficial deposits lava fields distribution of sector collapses and lava compositions are determined macauley and havre are large silicic intra oceanic caldera complexes for both concentric ridges on the outer flanks are interpreted as recording mega bedforms associated with pyroclastic density flows and edifice foundering other stratovolcanoes reveal complex histories with repeated cycles of tectonically controlled construction and sector collapse extensive basaltic flow fields and the development of summit craters and or small nested calderas combined with existing data for the southernmost arc segment we provide an overview of the spatial distribution and magmatic heterogeneity along similar to 780 km of the kermadec arc at 30 degrees 36 degrees 30 s coincident changes in arc elevation and lava composition define three volcano tectonic segments a central deeper segment at 32 degrees 20 34 degrees 10 s has basement elevations of 3200 m water depth and relatively simple stratovolcanoes dominated by low k series basalt basaltic andesite in contrast the adjoining arc segments have higher basement elevations typically 3 km coincide with the shallower arc segments the dominant mode of large caldera formation is interpreted as mass discharge pyroclastic eruption with syn eruptive collapse hence the shallower arc segments are characterized by both the generation of volatile enriched magmas from crustal melting and a reduced hydrostatic load allowing magma vesiculation and fragmentation to initiate and sustain pyroclastic eruptions proposed initiation parameters for submarine pyroclastic eruptions are water depths 70 wt sio2 and a high discharge rate c 2005 elsevier b v all rights reserved

the sedimentary record of the 1960 tsunami in two coastal lakes on isla de chiloe south central chile abstract this study describes sediments deposited by the tsunami following the 1960 great chilean earthquake mw 9 5 in two coastal lakes lakes cucao and huelde on the west coast of isla de chiloe south central chile 42 6 s sub bottom profiles and side scan sonar mosaics illustrate the sedimentary context of transects of gravity cores the stratigraphy of both lakes features gyttja sedimentation interrupted by the abrupt emplacement of a sandy layer with mud rip up clasts and a mud cap this sandy layer reflects a sudden change in sedimentary environment most probably caused by a high energy inundation radionuclide analyses 137cs and 210pb date the inundation deposit to shortly before the mid 1960s the only known event that matches the sedimentological and chronological criteria is the ad 1960 tsunami using grain size analysis and comparisons with samples from modern environments we demonstrate that the proximal seaward part of the deposit consists of a mixture of sand derived from subaerial sources and reworked gyttja lake sediment in the distal landward part of lake cucao the sand component is lost and the deposit consists entirely of remobilised lake sediments the repetition of tsunami deposit sequences in lake huelde suggests a minimum of three inundating waves sub bottom profiles and side scan sonar mosaics reveal tsunami inundation over the barrier and more prominently through the outlet river channel the dominant role of the river channel as a pathway for sediment transport is also described in core samples by tsunami deposits that fine away from the channel mouth the identification and description of the deposit left by a known tsunami provide important insights into tsunami sedimentation in coastal lakes and have the potential to help in the search for paleotsunami evidence

an examination of spatial variability in the timing and magnitude of holocene relative sea level changes in the new zealand archipelago holocene relative sea level rsl changes have been reconstructed for four regions within the new zealand archipelago the northern north island including northland auckland and the coromandel peninsula the southwest coast of the north island the canterbury coast south island and the otago coast south island in the north island the rsl highstand commenced c 8100 7240 cal yr bp when present mean sea level pmsl was first attained this is c 600 1400 years earlier than has been previously indicated for the new zealand region as a whole and is consistent with recent holocene rsl reconstructions from australia in north island locations the early holocene sea level highstand was quite pronounced with rsl up to 2 75 m higher than present in the south island the onset of highstand conditions was later with the first attainment of pmsl being between 7000 6400 cal yr bp in the mid holocene the northern north island experienced the largest sea level highstand with rsl up to 3 00 m higher than present this is demonstrably higher than the highstand recorded for the southwest north island and otago regions a number of different drivers operating at a range of scales may be responsible for the spatial and temporal variation in the timing and magnitude of rsl changes within the new zealand archipelago one possible mechanism is the north south gradient in rsl that would arise in the intermediate field around antarctica in response to the reduced gravitational attraction of the antarctic ice sheet ais as it lost mass during the holocene this gradient would be enhanced by the predicted deformation of the lithosphere in the intermediate field of the southern ocean around antarctica due to hydro isostatic loading and mass loss of the ais however no such long wavelength signals in sea surface height or solid earth deformation are evident in glacial isostatic adjustment gia model predictions for the new zealand region while research from australia has suggested that north south variations in holocene rsl changes due to hydro isostatic influences are limited or non existent at the regional to local scale post glacial meltwater loading on the continental shelf around new zealand is predicted by gia modelling to have a significant effect on the timing and magnitude of rsl changes through the phenomenon of continental levering the spatial variation in continental levering is controlled by the configuration of the coast and the width of the adjacent continental shelf with continental levering providing a robust explanation for the observed spatial and temporal variations in rsl changes further research is required to characterise the regional and local effects of different tectonic regimes wave climates and sediment regimes these are potentially very significant drivers of rsl variability at the regional to local scale however the magnitude of their potential effects remains equivocal

a probabilistic tsunami hazard study of the auckland region part i propagation modelling and tsunami hazard assessment at the shoreline regional source tsunamis represent a potentially devastating threat to coastal communities in new zealand yet are infrequent events for which little historical information is available it is therefore essential to develop robust methods for quantitatively estimating the hazards posed so that effective mitigation measures can be implemented we develop a probabilistic model for the tsunami hazard posed to the auckland region of new zealand from the kermadec trench and the southern new hebrides trench subduction zones an innovative feature of our model is the systematic analysis of uncertainty regarding the magnitude frequency distribution of earthquakes in the source regions the methodology is first used to estimate the tsunami hazard at the coastline and then used to produce a set of scenarios that can be applied to produce probabilistic maps of tsunami inundation for the study region the production of these maps is described in part ii we find that the 2 500 year return period regional source tsunami hazard for the densely populated east coast of auckland is dominated by events originating in the kermadec trench while the equivalent hazard to the sparsely populated west coast is approximately equally due to events on the kermadec trench and the southern new hebrides trench

geological and historical records of tsunami in australia abstract the indian ocean tsunami iot of 2004 has resulted in significant interest within australia about the record of tsunami for the continent because an understanding of tsunami hazard begins with a catalogue of past events here a preliminary catalogue of tsunami affecting australia is presented the catalogue contains entries for 57 tsunami events the oldest event is dated at 3 47 ga the most recent is the july 17th 2006 forty four tsunami were recorded on the new south wales coast although the nw coast of western australia records a significant number of events forty seven events have affected australia since ad1858 maximum run up for an historic event is 6 m asl whilst the maximum run up for a palaeotsunami event is reported at an elevation of at least 100 m asl twenty three percent of historic australian tsunami were generated by unknown causes and papua new guinea the solomon islands and indonesia collectively represent the most important source area of historic tsunami for australia geological records for palaeo and historic tsunami are identified and summarised the geological record of tsunami represents a potentially important source of information for australian tsunami however at the present time the geological record is both limited and controversial and future research should seek to re examine proposed geological evidence of tsunami from an analysis of this preliminary catalogue of australian tsunami a series of key research priorities have been identified to guide future research in the region

seismic driving of nationwide changes in geomorphology and prehistoric settlement a 15th century new zealand example abstract we propose a model for the seismic driving of environmental changes and illustrate it using a case study from new zealand dated to the 15th century ad a seismic staircase shows a chronological progression of environmental outcomes that includes tsunami rock avalanches vegetation disturbance rapid coastal dune building river aggradation and abandonment of prehistoric coastal settlements the 15th century event appears to be unique in the past millenium and is most notable for its period of rapid coastal dune building the coincidence of a catastrophic el nino episode in the mid 15th century ad may have served to move sediments rapidly through the terrestrial system thus delimiting clearly separate geomorphological after effects we contend that seismic driving is a major factor in determining paleoenvironmental change in tectonically active areas during the holocene and provides the palaeoenvironmental context within which smaller scale events operate

field study of wave attenuation on an offshore coral reef a major field experiment was conducted which obtained measurements of the attenuation and transformation of short gravity waves as they cross the windward edge of an offshore coral reef water level data were collected for over 3000 individual time series during a wide range of environmental conditions at the innermost measurement site which is located on the horizontal reef flat after the completion of wave breaking the upper bound of significant and maximum wave heights is limited to less than 40 and 60 of the reef flat water depth respectively as with significant wave height both the shape and energy level of the reef flat spectra are strongly affected by changes in reef flat water depth for higher tide levels the spectra on the reef flat closely mimic the corresponding incident spectra however the attenuation is greater for both lower frequencies and higher energy portions of the spectra this causes the reef flat spectra to be broader than those measured windward of the reef at lower water levels considerable energy losses due to wave breaking and bottom friction occur most of the energy loss comes from the vicinity of the spectral peak and energy shifts to harmonics of the peak of the spectrum can be seen

boron beryllium and sulfur in holocene sediments and peats of the nile delta egypt their use as indicators of salinity and climate abstract the concentrations of 14 major and trace elements b ba be co cr cu fe mn ni p s v zn and organic c in bulk sediment samples of holocene age from bore holes in the nile delta egypt are considered in terms of sediment grain size and depositional setting using this background information an attempt is made to evaluate paleosalinity and paleoclimatic change by geochemical analyses of peats in every sediment facies examined we find that grain size is a major controlling factor of geochemical composition but the b be ratio is helpful in paleoenvironmental interpretations organic matter content is the major factor affecting element concentrations in peats zn cr fe be cu mn concentrations on an organic matter free basis are lower in these organic rich layers than in other nile delta sediment facies the sulfur content of the peats indicates a decreased importance of freshwater input to holocene lagoons from about 8000 to 3400 years bp high boron beryllium ratios and the presence of gypsum in peats deposited between 6300 and 4900 years bp record the most evaporitic phase affecting this region this geochemical finding is in close agreement with results of other independent paleoclimatic studies which indicate the onset of arid conditions in northeast africa at about 5000 years bp

energy transfer between wind waves and low frequency oscillations on a fringing reef ipan guam field observations from a guam fringing reef are used to examine the cross reef energy exchange between high frequency sea and swell ss and low frequency infragravity ig and far infragravity fig waves energetic ss waves significant wave heights 2 4 m break at the outer reef leading to weak 1 m conditions on the shallow reef flat as ss waves shoal on the reef face before breaking ig and fig energy fluxes both increase through nonlinear energy transfer from the ss waves in contrast through the surf zone the ig energy flux decreases whereas fig flux increases the decrease in ig energy flux through the surf zone is attributed to breaking ss waves working against the incident bound ig wave energy which dominates breakpoint forced ig waves yielding a net flux decrease in contrast fig energy flux increases through the surf zone consistent with breakpoint forcing and the absence of an energetic bound fig component on the reef face ig and fig energy fluxes decay on the shallow reef flat due primarily to frictional dissipation with tidal modulations attributed to nonlinear conversion and friction forcing at fig frequencies may lead to a normal mode response on the reef with comparable incoming and outgoing fig energy fluxes at the outer reef flat depending on water level over the reef flat and the degree of frictional dissipation

wave transformation and shoreline water level on funafuti atoll tuvalu the influence of sea swell ss waves infragravity ig waves and wave setup on maximum runup rmax is investigated across different tidal stages on fatato island funafuti atoll tuvalu field results illustrate that ss waves are tidally modulated at the shoreline with comparatively greater wave attenuation and setup occurring at low tide versus high tide a shoreward increase in ig wave height is observed across the 100 m wide reef flat at all tidal elevations with no tidal modulation of ig wave height at the reef flat or island shoreline a 1 d shock capturing green naghdi solver is used to replicate the field deployment and analyze rmax model outputs for ss wave height ig wave height and setup at the shoreline match field results with model skill 0 96 model outputs for rmax are used to identify the temporal window when geomorphic activity can occur on the beach face during periods of moderate swell energy waves can impact the beach face at spring low tide due to a combination of wave setup and strong ig wave activity under mean wave conditions the combined influence of setup ig waves and ss waves results in interaction with island sediment at midtide at high tide ss and ig waves directly impact the beach face overall wave activity is present on the beach face for 71 of the study period a significantly longer duration than is calculated using mean water level and topographic data

tsunami and palaeotsunami depositional signatures and their potential value in understanding the late holocene tsunami record in recent years much research on modern and palaeotsunami deposits has been published from these studies a range of signature types has been identified identifying and dating such deposits is an important element in understanding late holocene tsunami hazard and risk however important questions such as do modern and palaeotsunami leave similar or dissimilar traces do tsunami leave the same signatures all around the world or are there significant variations and what is the actual record of tsunami in different parts of the world still remain answering these questions is not an easy task but examining megatsunami flood deposits should shed some light on these questions because such high magnitude events should leave very clear and detailed traces within the coastal landscape the coast of se australia is reported to have been affected by numerous palaeomegatsunami in the late holocene as such the coast of new south wales offers an important natural laboratory to examine in detail deposits associated with such events here we summarize the published characteristics of modern and palaeotsunami deposits globally and within australia we briefly outline the tsunami risk to australia before examining a site called minnamurra point on the coastline of se australia south of sydney that has previously been described as containing evidence for a palaeomegatsunami of an unknown age we describe the results of a detailed coastal survey field stratigraphic investigation and various standard laboratory analyses surprisingly we are unable to replicate the previously reported findings of tsunami deposits whilst we prefer the interpretation that the sequence is an in situ soil the sediment sequence examined contains none of the usually reported lines of evidence to demonstrate tsunami provenance we recognize and discuss the significance and difficulty of identifying tsunami deposits in the field and consider the implications of our findings to the wider debate about the preservation of tsunami deposited sediments

tsunami sediments and their foraminiferal assemblages abstract tsunami hazard assessment begins with a compilation of past events that have affected a specific location given the inherent limitations of historical archives the geological record has the potential to provide an independent dataset useful for establishing a richer chronologically deeper time series of past events recent geological studies of tsunami are helping to improve our understanding of the nature and character of tsunami sediments wherever possible geologists should be working to improve the research tool kit available to identify past tsunami events marine foraminifera single celled heterotrophic protists have often been reported as present within tsunami deposited sediments but in reality little information about environmental conditions and by analogy the tsunami that deposited them has been reported even though foraminifera have an enormous capacity to provide meaningful palaeo environmental data here we review what foraminifera are describe their basic form and significance summarise where they have been reported in tsunami sediments and identify what can be learnt from them we review the gaps in our understanding and make recommendations to assist researchers who examine foraminiferal assemblages in order to enhance their use within tsunami geology

the influence of sea level rise and changes in fringing reef morphology on gradients in alongshore sediment transport 1 climate change induced alterations to coral reef ecosystems in combination with sea level rise have the potential to significantly alter wave dissipation across reefs leading to shifts in alongshore sediment transport gradients and alterations to tropical coastlines we used delft3d to model schematized profiles of two reef flat widths based on the south molokai hawaii coast simulated anthropogenic modifications include incremental degradation of the reef structure as well as sea level rise our findings indicate that sea level rise has a greater relative effect on wave energy flux and alongshore sediment transport over a wide flat whereas both reef degradation and sea level rise exert similar influence over a narrow flat these results suggest reefs that vary in width alongshore are more likely to experience changes in alongshore sediment transport gradients and therefore shifts in shoreline erosion and accretion patterns than more uniform reef systems

wave dynamics of a pacific atoll with high frictional effects we report field measurements of waves and currents made from september 2011 to july 2014 on palmyra atoll in the central pacific that were used in conjunction with the swan wave model to characterize the wave dynamics operant on the atoll our results indicate that wave energy is primarily from the north during the northern hemisphere winter and from the south in the northern hemisphere summer refraction of waves along the reef terraces due to variations in bathymetry leads to focusing of waves in specific locations bottom friction modeled with a modified bottom roughness formulation is the significant source of wave energy dissipation on the atoll a result that is consistent with available observations of wave damping on palmyra indeed modeled wave dissipation rates from bottom friction are on average larger than dissipation rates due to breaking and are an order of magnitude larger than what has been observed on other less geometrically complex reefs a result which should be corroborated with future in situ measurements the swan wave model with a modified bottom friction formulation better predicts bulk wave energy properties than the existing formulation at our measurement stations the near bed squared velocity a proxy for bottom stress shows strong spatial variability across the atoll and exerts control over geomorphic structure and benthic community composition

a tsunami ca 6300 years bp and other holocene environmental changes northern hawke s bay new zealand abstract sediment cores collected in a coastal lagoon a few kilometres east of wairoa northern hawke s bay new zealand were examined using sedimentological geochemical palynological and micropaleontological analyses a distinct short lived catastrophic saltwater inundation csi about 6300 years bp and possibly other minor marine incursions are preserved in the coastal estuarine to lagoonal freshwater sedimentary sequences which have been deposited in the last 6500 years the csi is characterised by a gravel unit that thins landward and decreases in particle size to sand within a sequence consisting mainly of brackish estuarine muds diatom assemblages indicate a marked change from the shallow brackish estuarine muds to marine gravels and sands to brackish estuarine muds the marine influence in the gravel and sand is also shown by the presence of marine dinoflagellates and a peak in na rb sedimentological chemical and paleontological in particular diatoms evidence indicates it is a csi we conclude that this was a tsunami and propose the most likely propagating mechanisms marine influence decreases upcore and totally freshwater conditions are evident in the upper section of the cores the geochemistry of the sediments mainly reflects the change in stratigraphy with distinct signatures for tephra na fe cr organic rich and peat units as br and the coarse gravel sand csi unit na rb cr fe but it is also indicative of changes in depositional environment the change in chemistry na rb in the csi event is indicative of a saltwater influence whereas a marked change in s content suggests a sudden change from brackish to freshwater conditions shortly after 4800 years bp another peak in s and br content about 3200 years bp may indicate another temporary change to brackish conditions

a late holocene record of environmental changes from coastal wetlands abel tasman national park new zealand abstract article size organic content loss on ignition loi geochemistry radiocarbon and 137cs analyses were carried out on paired cores taken from wainui totaranui and awaroa inlets abel tasman national park a 1700 year record of long and short term environmental changes was produced representing a sedimentary and geochemical sequence from tidal flat to mature salt marsh the sequence is punctuated by a series of short term environmental changes namely tsunami establishment of salt marsh and european settlement long term environmental changes include fluctuating accretion rates and relative sea level rise tsunami signatures include i a peak in fines ii contemporaneous or delayed peak in organic content and or loi iii contemporaneous peaks in fe and or s iv dilution of anthropogenic contaminants and v visible change in the sediments ruptures of the wellington and west wairarapa faults are considered to be the tsunamigenic sources pre european sediment accretion rates in abel tasman national park range from 0 5 to 1 7 mm a with post european settlement rates increasing to 1 6 2 7 mm a in the past 30 years rates have increased to 2 3 3 3 mm a the component of relative sea level rise is estimated to be about 1 3 2 2 mm a which compares favourably with the nearest tidal records from wellington

multi proxy records of regionally sourced tsunamis new zealand abstract a multi proxy study of sediment cores from kaituna bay mimiwhangata in northern new zealand has produced a record of three palaeotsunamis dated to around 6500 cal yr bp 2800 cal yr bp and 1450 ad these events punctuate a coastal palaeoenvironmental history spanning the last 8000 years or more in which the site progressed from a semi open lagoon to a freshwater swamp proxies used included stratigraphy geochemistry palynology diatoms foraminifera geomorphology and a regional palaeotsunami synthesis the identification of tsunamigenic sources for these events is tentative we propose that the two oldest events are associated with a source in the tonga kermadec trench region with the most recent possibly associated with the kuwae caldera collapse in 1452 1453 ad palaeotsunami deposits contemporaneous with the estimated age of the three events identified in this study were used to assist in identifying possible source regions the development of regional and national palaeotsunami databases is in its infancy but as more data become available the ability to determine the source magnitude and frequency of past events will improve this will greatly enhance our understanding of the regional risk from tsunamis

facies architecture morphostratigraphy and sedimentary evolution of a rapidly infilled holocene incised valley estuary the lower manawatu valley north island new zealand water well logs and vibracores recovered from the lower manawatu valley record the facies architecture morphostratigraphy and sedimentary evolution of this drowned river incised valley estuary over the past c 30 000 years the manawatu incised valley estuary was rapidly infilled during the holocene and as a result preserves a complete record of holocene estuary evolution the base of the holocene fill is marked by fluvial gravels deposited by the manawatu river during the lowstand of the last glacial maximum the gravels are overlain by back stepping transgressive fluvial silts and clays the transgressive fluvial unit is present only in the lower reaches of the valley due to accelerated sea level rise during the latter stages of the marine transgression large volumes of transgressive marine sediment were delivered to the mouth of the valley by rising sea levels during the early holocene forming a large subaqueous tidal delta this delta accreted and subsequently evolved to form a subaerial barrier in the mid holocene as sea levels stabilised during the sea level highstand the central basin of the estuary was rapidly infilled by marine and fluvial sediment and consequently lacks the mud facies characteristic of less rapidly evolved estuaries the transition from the sandy central basin estuarine environment to the overlying floodplain environment was extremely rapid in some locations in the valley the transitional fluvial bay head delta is missing completely while in most locations it is present only as a very thin deposit indicative of this rapid environmental transition infilling of the estuarine central basin was extremely rapid taking only 2000 2700 years the unique features of the manawatu estuary s evolutionary history are interpreted to primarily reflect the rapid infilling of the palaeo estuary driven by the high rates of sediment supplied to the valley from both marine and fluvial sources

tsunami hazard posed to new zealand by the kermadec and southern new hebrides subduction margins an assessment based on plate boundary kinematics interseismic coupling and historical seismicity we assess the tsunami hazard posed to new zealand by the kermadec and southern new hebrides subduction margins neither of these subduction zones has produced tsunami large enough to cause significant damage in new zealand over the past 150 years of well recorded history however as this time frame is short compared to the recurrence interval for major tsunamigenic earthquakes on many of the earth s subduction zones it should not be assumed that what has been observed so far is representative of the long term for each of these two subduction zones we present plate kinematic and fault locking results from block modelling of earthquake slip vector data and gps velocities the results are used to estimate the current rates of strain accumulation on the plate interfaces where large tsunamigenic earthquakes typically occur we also review data on the larger historical earthquakes that have occurred on these margins as well as the global cmt catalogue of events since 1976 using this information we have developed a set of scenarios for large earthquakes which have been used as initial conditions for the comcot tsunami code to estimate the subsequent tsunami propagation in the southwest pacific and from these the potential impact on new zealand has been evaluated our results demonstrate that there is a significant threat posed to the northland and coromandel regions of new zealand should a large earthquake m w 8 5 occur on the southern or middle regions of the kermadec trench and that a similarly large earthquake on the southern new hebrides trench has the potential to strongly impact on the far northern parts of new zealand close to the southern end of the submarine three kings ridge we propose logic trees for the magnitude frequency parameters of large earthquakes originating on each trench which are intended to form the basis for future probabilistic studies

onshore tsunami sediment transport mechanisms inferred from heavy mineral assemblages the aim of this study is to discuss and to extend the characterization of palaeo tsunami deposits and their source materials based upon the detailed study of their heavy mineral assemblages results obtained from three distinct locations portugal scotland and indonesia different coastal contexts and chronologies the tsunami events studied took place at 1500 cal yr bp ad 1755 and 2004 are summarized and discussed in order to contribute to the sedimentological study of onshore palaeo tsunami deposits results indicate that heavy mineral assemblages primarily reflect local specific conditions for example in the portuguese sites ca 90 of the heavy mineral population consists of tourmaline andalusite staurolite whereas in the scottish samples garnet amphiboles can be dominant in 90 of the assemblage where at the indonesian study site amphiboles andalusite were the most frequent minerals the application of principal component analysis for each site reveals that the first two components explain at least 55 of the total variance in the three studied areas hydraulic sorting by density was observed and a higher presence of the denser heavy minerals of the assemblages was detected however it is important to stress that the sediment source plays a key role in the establishment of the heavy mineral assemblages of the palaeo tsunami deposits in this study relationships between the likely source sediments and the palaeo tsunami deposits were described and whenever possible sediment sources were clearly identified furthermore it was also possible to detect the backwash signal using the analysis of the heavy minerals e g higher frequency of denser minerals or variation in the presence of rounded or euhedral zircon the work presented here in contributing to the enhancement of sedimentological criteria presently available to recognize and differentiate extreme marine inundation deposits also highlights new areas for future research

geochemical data as indicators of palaeosalinity in coastal organic rich sediments abstract a geochemical study of extractable major minor and trace elements peatlands from e spain elucidated variations in salinity related to the interpretation of relative sea level change samples were taken from different peatlands from the subsiding valencia castellon quaternary basin e spain these correspond to back barrier marshes with brackish and freshwater influence containing carex juncus typha and phragmites samples from a highland sphagnum moss freshwater peat bog were also included for comparison this paper categorizes palaeosalinity indicators in this coastal peat deposits as follows b br i na s ge u this compares with low rank coal which shows the following relationship b br i s na ge u the formulation of an index for characterising the organic detrital content using k or al concentration is also proposed this resulted in the following salinity index for peat b k br k i k na k s k ge k u k and for low rank coal b k br k i k s k na k ge k u k

the 1452 or 1453 a d kuwae eruption signal derived from multiple ice core records greatest volcanic sulfate event of the past 700 years 1 we combined 33 ice core records 13 from the northern hemisphere and 20 from the southern hemisphere to determine the timing and magnitude of the great kuwae eruption in the mid 15th century we extracted volcanic deposition signals by applying a high pass loess filter to the time series and examining peaks that exceed twice the 31 year running median absolute deviation by accounting for the dating uncertainties associated with each record these ice core records together reveal a large volcanogenic acid deposition event during 1453 1457 a d the results suggest only one major stratospheric injection from the kuwae eruption and confirm previous findings that the kuwae eruption took place in late 1452 or early 1453 which may serve as a reference to evaluate and improve the dating of ice core records the average total sulfate deposition from the kuwae eruption was 93 kg so4 km 2 in antarctica and 25 kg so4 km 2 in greenland the deposition in greenland was probably underestimated since it was the average value of only two northern greenland sites with very low accumulation rates after taking the spatial variation into consideration the average kuwae deposition in greenland was estimated to be 45 kg so4 km 2 by applying the same technique to the other major eruptions of the past 700 years our result suggests that the kuwae eruption was the largest stratospheric sulfate event of that period probably surpassing the total sulfate deposition of the tambora eruption of 1815 which produced 59 kg so4 km 2 in antarctica and 50 kg so4 km 2 in greenland

palaeotsunami deposits a new zealand perspective abstract over the past few years geological investigations of coastal sediments in new zealand have provided evidence of past tsunami the identification of palaeotsunami deposits is helping to increase our knowledge about the sources magnitude and frequency of these events this paper briefly outlines both the key diagnostic characteristics used in new zealand to identify palaeotsunami deposits and the emerging findings related to recent research