surges around the hawaiian islands from the 2011 tohoku tsunami 1 the 2011 tohoku tsunami devastated the northeastern japan coasts and caused localized damage to coastal infrastructure across the pacific the tsunami resulted in strong currents around the hawaiian islands that led to closure of harbors and marinas for up to 38 h after its arrival we utilize a nonhydrostatic model to reconstruct the tsunami event from the seismic source for elucidation of the physical processes and inference of the coastal hazards a number of tide gauges bottom pressure sensors and adcps provided point measurements for validation and assessment of the model results in hawaii spectral analysis of the computed surface elevation and current reveals complex flow patterns due to multiscale resonance standing waves with 33 75 min period develop along the island chains while oscillations of 27 min or shorter are primarily confined to an island or an island group with interconnected shelves standing edge waves with periods 16 min or shorter which are able to form nodes on the reefs and inside harbors are the main driving force of the observed coastal currents resonance and constructive interference of the oscillation modes provide an explanation of the impacts observed in hawaii with implications for emergency management in pacific island communities

effects of source faulting and fringing reefs on the 2009 south pacific tsunami inundation in southeast upolu samoa the subduction zone along the northern tonga trench has the highest plate convergence rate in the world but limited records of its seismic and tsunamigenic activities in 2009 a tsunami generated

sub ice topography in patriot hills west antarctica first results of a newly developed high resolution fm cw radar system we present a newly developed high resolution frequency modulated continuous wave fm cw radar system for sounding the sub ice topography the system working in the frequency range from 200 to 400 mhz was developed to measure thickness and internal layers in cold ice with a resolution better than 1 m this system has the potential to measure accumulation rates an important input for improved knowledge of the mass balance of polar ice sheets first measurements for the test calibration and optimization of the new ice sounder were made in december 2005 near the ellsworth mountains specifically in patriot hills west antarctica at 80 18 s 81 22 w the complete radar system was installed on a ski mounted support frame and towed by hand across the ice surface the measurement results show the capability of this system to measure ice thickness up to 1000 m and to define internal layers within the ice body

equilibrium density and expansivity of silicate melts in the glass transition range equilibrium volumes and expansivities of three liquids in the system anorthite caal2si2o8 diopside camgsi2o6 have been derived from dilatometric measurements of the equilibrium length of samples in the glass transition range the typical temperature range of 40 k for the measurements is limited at low temperature by the very long times necessary to reach structural equilibrium and at high temperature by the penetration of the rod used to measure sample dilatation despite such narrow intervals the expansivities are determined to better than 3 thanks to the high precision with which length changes are measured the coefficient of volume thermal expansion 1 v dv dt of the fully relaxed liquid just above the glass transition is found to decrease linearly from diopside composition 139 4 10 6 k 1 to anorthite composition 59 2 10 6 k 1 these values are greater than those determined for the same liquids at superliquidus temperatures demonstrating that expansivities of silicate melts may decrease markedly with increasing temperature a predictive model based upon partial molar volumes which vary as a linear function of the logarithm of temperature is proposed

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

forcing of resonant modes on a fringing reef during tropical storm man yi 1 open basin resonant modes have been observed at tidal frequencies on coastal shelves but their excitation on coral reef platforms has only been suggested the topography of and water depth over most fringing reefs correspond to resonant periods that are the order of tens of minutes and fall outside of the energetic part of the wave spectrum during tropical storm man yi low frequency near resonant oscillations dominated the variance of the sea surface elevation at the shoreline of ipan reef guam the excitation of the resonant modes resulted both from a large increase in water level over the reef due to wave setup which increased the resonant frequencies and the occurrence of wave group forcing with time scales commensurate with these increased resonant frequencies

laboratory study of wave processes over fringing reefs with a reef flat excavation pit abstract dredging and excavation activities on fringing reefs have potential impacts such as the coastal inundation during extreme wave events and no published laboratory experiments have addressed this issue to verify the previous findings from both field observations and numerical simulations and focus on evaluating the alteration of wave processes over fringing reefs by an excavation pit a new set of laboratory experiments are carried out in a wave flume based on an idealized fringing reef model with and without a reef flat pit experimental results are reported for a series of spectral wave conditions and pit widths it is found that the sea and swell ss waves near the shoreline can be increased or decreased depending both on the incident wave condition and the pit width whereas the infragravity ig waves reaching the shoreline are consistently reduced by an average of 10 5 when the pit exists and such reduction is enhanced with increasing pit width an analysis of the involved hydrodynamic processes indicates that the variation of shoreline ss wave energy depends on the relative importance of such processes as increased wave reflection around the pit decreased dissipation with wave breaking decreased energy transfer with nonlinear wave wave interaction and wave resonance excited in the pit however the reduction of shoreline ig wave energy is due to the combined effects of a disruption of resonant standing wave pattern on the reef flat and increased wave reflection around the pit

modeling of 500 year tsunamis for probabilistic design of coastal infrastructure in the pacific northwest abstract this paper describes the development of tsunami scenarios from the national seismic hazard maps for design of coastal infrastructure in the pacific northwest the logic tree of cascadia earthquakes provides four 500 year rupture configurations at moment magnitude 8 8 9 0 and 9 2 for development of probabilistic design criteria a planar fault model describes the rupture configurations and determines the earth surface deformation for tsunami modeling a case study of four bridge sites at siletz bay oregon illustrates the challenges in modeling of tsunamis on the pacific northwest coast a nonlinear shallow water model with a shock capturing scheme describes tsunami propagation across the northeastern pacific as well as barrier beach overtopping bore formation and detailed flow conditions at siletz bay the results show strong correlation with geological evidence from the six paleotsunamis during the last 2800 years the proposed approach allows determination of tsunami loads that are consistent with the seismic loads currently in use for design of buildings and structures

a mid holocene candidate tsunami deposit from the nw cape western australia although extreme wave events are frequent along the northwestern coast of western australia and tsunamis in 1994 and 2006 induced considerable coastal flooding locally robust stratigraphical evidence of prehistoric tropical cyclones and tsunamis from this area is lacking based on the analyses of x ray computed microtomography ct of oriented sediment cores multi proxy sediment and microfaunal analyses optically stimulated luminescence osl and 14c ams dating this study presents detailed investigations on an allochthonous sand layer of marine origin found in a back barrier depression on the nw cape range peninsula the event layer consists of material from the adjacent beach and dune fines and thins inland and was traced up to 400 m onshore although a cyclone induced origin cannot entirely be ruled out the particular architecture and fabric of the sediment rip up clasts and three subunits point to deposition by a tsunami as such it represents the first stratigraphical evidence of a prehistoric mid holocene tsunami in nw western australia it was osl dated to 5400 4300 years ago thus postdating the regional mid holocene sea level highstand

wave transformation over coral reefs ocean wave attenuation on coral reefs is discussed using data obtained from a preliminary field experiment and from the seasat altimeter marked attenuation of the waves is observed the rate being consistent with existing theories of bottom friction and wave breaking decay in addition there is a significant broadening of the spectrum during propagation across reefs three dimensional effects such as refraction and defraction can also lead to substantial wave height reduction for significant distances adjacent to coral reefs as a result a matrix of such reefs provides significantly more wave attenuation than may initially be expected

observation of the 2009 samoa tsunami by the neptune canada cabled observatory test data for an operational regional tsunami forecast model 1 as part of the neptune canada cabled seafloor observatory an array of six high precision bottom pressure recorders was installed in the late summer of 2009 at depths from 100 to 2600 m seaward of the southwest coast of vancouver island in the northeast pacific the instruments transmit 1 sec bottom pressure data at roughly 0 1 mm equivalent sea level height to the data management and archiving system dmas at the university of victoria on september 30 2009 the array recorded waves of 2 5 to 6 cm amplitude associated with the transoceanic tsunami generated by the mw 8 1 samoa earthquake in the south pacific these open ocean observations were uncontaminated by coastal effects demonstrating that neptune records from future tsunami events can be effectively used as realtime input to a regional numerical tsunami forecast model we validate this proposition by showing that wave forms simulated by the regional model using the leading train of waves of the 2009 event are in good agreement with observed tsunami records for both the shelf stations and nearby coastal tide gauges tsunami waves simulated by this model are also significantly more accurate for local regions than those determined by global scale tsunami models this ability to assimilate pristine open ocean data from the cabled observatory into an operational tsunami forecast model makes it possible to provide updated wave information that could help mitigate the impact of future tsunamis approaching the west coast of british columbia and northern washington state

excitation of basin wide modes of the pacific ocean following the march 2011 tohoku tsunami this study is an attempt towards understanding the sources of long oscillations observed within the pacific ocean following the 11 march 2011 tohoku earthquake we present evidence that extremely long modes of the pacific ocean in the range of 2 48 h were excited by this giant tsunami a numerical approach was employed to calculate the basin wide modes of the pacific ocean resulting in 49 modes in the range of 2 48 h we studied 15 tide gauge records around the pacific ocean in order to extract basin wide modes of the pacific ocean excited by this transoceanic tsunami spectral analysis of these tide gauge records showed that some of the calculated basin wide modes were indeed excited by the tohoku tsunami the observed modes ranged from 2 to 49 8 h we attributed the long oscillations of the pacific ocean during the 2011 tohoku tsunami to the excitation of these basin wide modes which can be grouped into global modes 15 48 h and regional modes 2 15 h we classified the signals on the tide gauges into three groups 1 basin wide modes 1 5 h 2 the tsunami source periods 20 90 min and 3 local bathymetric effects 20 min the average contributions to the total tsunami energy were 6 4 for the basin wide mode 64 1 for the tsunami source and 29 5 for the local bathymetry although the ratios varied from station to station simulations suggest that the amount of contribution of basin effects to the total tsunami energy depends on the location of the tsunami source

geological effects and implications of the 2010 tsunami along the central coast of chile abstract geological effects of the 2010 chilean tsunami were quantified at five near field sites along a 200 km segment of coast located between the two zones of predominant fault slip field measurements including topography flow depths flow directions scour depths and deposit thicknesses provide insights into the processes and morphological changes associated with tsunami inundation and return flow the superposition of downed trees recorded multiple strong onshore and alongshore flows that arrived at different times and from different directions the most likely explanation for the diverse directions and timing of coastal inundation combines 1 variable fault rupture and asymmetrical slip displacement of the seafloor away from the epicenter with 2 resonant amplification of coastal edge waves other possible contributing factors include local interaction of incoming flow and return flow and delayed wave reflection by the southern coast of peru coastal embayments amplified the maximum inundation distances at two sites 2 4 and 2 6 km respectively tsunami vertical erosion included scour and planation of the land surface inundation scour around the bases of trees and channel incision from return flow sheets and wedges of sand and gravel were deposited at all of the sites locally derived boulders up to 1 m in diameter were transported as much as 400 m inland and deposited as fields of dispersed clasts the presence of lobate bedforms at one site indicates that at least some of the late stage sediment transport was as bed load and not as suspended load most of the tsunami deposits were less than 25 cm thick exceptions were thick deposits near open ocean river mouths where sediment supply was abundant human alterations of the land surface at most of the sites provided opportunities to examine some tsunami effects that otherwise would not have been possible including flow histories boulder dispersion and vegetation controls on deposit thickness

comment on supercooled diopside melt confirmation of temperature dependent expansivity container based dilatometry by j gottsman and d b dingwell

observations of wave transformation over a fringing coral reef and the importance of low frequency waves and offshore water levels to runup overwash and coastal flooding many low lying tropical islands are susceptible to sea level rise and often subjected to overwash and flooding during large wave events to quantify wave dynamics and wave driven water levels on fringing coral reefs a 5 month deployment of wave gauges and a current meter was conducted across two shore normal transects on roi namur island in the republic of the marshall islands these observations captured two large wave events that had waves with maximum heights greater than 6 m with peak periods of 16 s over the fore reef the larger event coincided with a peak spring tide leading to energetic highly skewed infragravity 0 04 0 004 hz and very low frequency 0 004 0 001 hz waves at the shoreline which reached heights of 1 0 and 0 7 m respectively water surface elevations combined with wave runup reached 3 7 m above the reef bed at the innermost reef flat adjacent to the toe of the beach resulting in flooding of inland areas this overwash occurred during a 3 h time window that coincided with high tide and maximum low frequency reef flat wave heights the relatively low relief characteristics of this narrow reef flat may further drive shoreline amplification of low frequency waves due to resonance modes these results 1 demonstrate how the coupling of high offshore water levels with low frequency reef flat wave energetics can lead to large impacts along fringing reef lined shorelines such as island overwash and 2 lend support to the hypothesis that predicted higher sea levels will lead to more frequent occurrences of these extreme events negatively impacting coastal resources and infrastructure

the importance of explicitly modelling sea swell waves for runup on reef lined coasts abstract the importance of explicitly modelling sea swell waves for runup was examined using a 2d xbeach short wave averaged surfbeat xb sb and a wave resolving non hydrostatic xb nh model of roi namur island on kwajalein atoll in the republic of marshall islands field observations on water levels wave heights and wave runup were used to drive and evaluate both models which were subsequently used to determine the effect of sea level rise and extreme wave conditions on wave runup and its components results show that specifically modelling the sea swell component using xb nh provides a better approximation of the observed runup than xb sb which only models the time variation of the sea swell wave height despite good model performance of both models on reef flat water levels and wave heights xb sb has a bias of 0 108 0 057 m and scatter index of 0 083 0 639 whereas xb nh has bias of 0 132 0 055 m and 0 122 0 490 respectively however both models under predict runup peaks the difference between xb sb and xb nh increases for more extreme wave events and higher sea levels as xb nh resolves individual waves and therefore captures ss wave motions in runup however for even larger forcing conditions with offshore wave heights of 6 m the island is flooded in both xb sb and xb nh computations regardless the sea swell wave energy contribution in such cases xb sb would be adequate to model flooding depths and extents on the island while requiring 4 5 times less computational effort

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

hazard assessment during caldera unrest at the campi flegrei italy a contribution from gravity height gradients hazard assessment and risk mitigation at restless calderas is only possible with adequate geophysical monitoring we show here how detailed long term micro gravity and deformation surveys may contribute to hazard assessment at the campi flegrei caldera cfc in italy by evaluating gravity height change g h gradients obtained during ground inflation and deflation between 1981 and 2001 such gradients provide a framework from which to assess the likelihood and type of volcanic eruptions our new analysis of unrest at the cfc allows us to separate noise during the gravity survey from the signal of deep seated magmatic processes this facilitates identification of the dynamics within the magma reservoir beneath the cfc we found that magma replenishment during rapid uplift between 1982 and 1984 was insufficient probably by one to two orders of magnitude to trigger an eruption similar to the 1538 monte nuovo eruption the most recent volcanic eruption within the cfc furthermore our interpretation of g h gradients for the ongoing period of deflation since 1984 suggests that eruptive volcanic activity is not imminent short periods of minor inflation associated with large gravity changes since 1981 are interpreted to reflect noise which to some degree is probably due to sub surface mass density changes within shallow hydrothermal systems beneath the cfc indicating no risk of eruptive volcanic activity we propose that monitoring g h gradients at restless calderas is essential as a caldera develops from a state of unrest to a state where volcanic eruptions have to be anticipated adoption of this method for the several tens of restless calderas world wide will provide early warning of changes in or increase of activity at these supervolcanoes

modeling wave processes over fringing reefs with an excavation pit abstract the excavation of reef flat sand and aggregate for engineering projects is a common practice on atoll islands with attendant coastal management and hazard mitigation issues to assess the impact of reef flat excavation pits on wave transformation a numerical study is carried out based on one dimensional weakly dispersive highly nonlinear boussinesq equations model simulations are compared to field observations made at majuro atoll republic of the marshall islands ford et al 2013a at a 75 m wide fringing reef flat with a 17 m wide 4 m deep excavation pit and at an adjacent unmodified reef flat with a calibrated empirical breaking model and uniform friction coefficient the numerical model is shown to satisfactorily reproduce the observed sea and swell ss and infragravity ig frequency band wave heights for a moderate amplitude wave event by removing the lateral morphological differences of the field experiment the model shows that an excavation pit reduces increases shoreline ig ss wave heights compared to numerical tests without the pit in qualitative agreement with ford et al 2013a an eof analysis demonstrates that the reduction in ig wave heights is associated with modifications of the and wavelength ig standing modes across the reef caused by the pit model tests are used to evaluate the effects of cross reef pit location and width on wave transformation shoreline wave heights are least affected by a pit located near the reef crest and both ss and ig wave heights increase as the pit location moves shoreward shoreline wave heights are an increasing function of pit width as the increase in ss wave height exceeds the decrease in ig wave height produced by the pit the effects of incident wave height and spectral bandwidth are also examined for the reef with and without pit it is found that both shoreline ss and ig wave heights increase with the increasing incident wave height for both profiles the numerical model results also demonstrate that the shoreline response is sensitive to the bandwidth of the incident wave spectrum and larger ig shoreline wave heights are excited for narrower spectral bandwidths until wave reflection limits the forcing

the structure of haplobasaltic glasses investigated using x ray absorption near edge structure xanes spectroscopy at the si al mg and o k edges and ca si and al l2 3 edges abstract x ray absorption near edge structure xanes spectroscopy has been used to investigate the local structural environments around each of the elements within the haplobasaltic system the xanes results reveal both linear changes in ca o and si whereas non linear changes are also observed for si as well as al and mg unexpectedly both si and al spectra show complex edge structure that varies non linearly across the join the si l 2 3 edge results suggest that the si environment in an100 is very similar to that in crystalline anorthite whereas the di100 and diopside spectra show large offsets the l 3 and l 2 peaks display a linear behavior whereas peak b of the si l 2 3 spectra displays a non linear behavior displaying a maximum position at the di40 and di100 compositions and decreasing in between we estimate the si o bond length from shift in the peak b position which suggests a change in bond length between 1 58 and 1 66 a across the join the al k edge spectra suggests that there is a constant decrease in the inter tetrahedral angle as al is added the local mg environment displays non linear changes in intensity and for compositions with an content greater than di40 it appears that 4 mg plays an important role whereas 5 mg is dominant in diopside rich melts though octahedral coordinated mg cannot be ruled out the oxygen environment appears similar to crystalline anorthite in the haplobasaltic system calcium is present in highly distorted sites that are dominantly 7 ca in anorthite rich glasses whereas 8 ca is more important in diopside rich glasses these results provide additional independent constraints on the atomic structure of haplobasaltic silicate melts and highlight the need for further investigation into the relationships between network formers modifiers and the oxygen to which they are bound

the effects of dissolved co2 on the density and viscosity of silicate melts a preliminary study a potassium silicate liquid with 56 9 mol sio2 ks1 3 has been used as a model system to determine at 1 bar the influence of carbon dioxide on the viscosity and density of magma for the maximum concentration of 3 5 wt that could be dissolved the viscosity decreases by two orders of magnitude near the glass transition at around 750 k for 1 wt co2 the decrease is 1 and only 0 04 log unit at 750 and 1500 k respectively dissolved co2 has a composition independent partial molar volume of 25 6 0 8 cm3 mol in glasses at room temperature and does not affect the thermal expansion coefficient of the supercooled liquid which is 12 3 0 3 10 5 k 1 for co2 contents varying from 0 6 to 2 2 wt qualitatively these effects are similar to those of water however the density of dissolved co2 varies from about 1 7 to 1 5 g cm3 in a 700 k interval above the glass transition and lowers the density of the glass less than water whose density decreases from 1 5 to 1 2 g cm3 under the same conditions the relevance of these results to natural magma is finally pointed out

factors responsible for the limited inland extent of sand deposits on leyte island during 2013 typhoon haiyan previous geological studies suggest that the maximum inland extent of storm induced sand deposits is shorter but their thickness is larger than those of tsunami induced sand deposits however factors that determine the maximum extent and thickness of storm deposits are still uncertain we conducted numerical simulations of storm surge waves and sediment transport during typhoon haiyan in order to understand the distribution and sedimentary processes responsible for storm deposits numerical results showed that wave induced currents slightly offshore were strong but attenuated rapidly in the inland direction after wave breaking therefore sediments were not transported far inland by waves and storm surge consequently the maximum inland extent of storm deposits was remarkably shorter than the inland extent of inundation we also revealed that vegetation roughness coefficient and typhoon intensity greatly affect the calculation of maximum extent and thickness distribution of storm deposits as the duration of wave impact on a coast is relatively long during a storm hours compared to minutes for a tsunami sediments are repeatedly supplied by multiple waves therefore storm deposits tend to be thicker than tsunami deposits and multiple layers can form in the internal sedimentary structure of the deposits we infer that limitation of the sand deposit to within only a short distance inland from the shoreline and multiple layers found in a deposit can be used as appropriate identification proxies for storm deposits

shelf resonance and impact of near field tsunami generated by the 2010 chile earthquake 1 the 2010 chile earthquake of mw 8 8 generated a destructive tsunami in the near field that resulted in warnings across the pacific numerical modeling shows trapping and amplification of the energy over the continental shelf and slope a spectral analysis of the computed surface elevation reveals resonance oscillations with periods up to 129 min along the central chile coast the temporal and spectral data provides an explanation for the long period waves recorded by dart buoys and the prolonged wave activities and belated impacts reported by residents and survey teams the present study of the 2010 chile tsunami together with those of the 2006 kuril and 2009 samoa tsunamis has directly associated shelf resonance with impacts on insular and continental coasts and provided a tool to identify at risk localities in tsunami hazard assessment

the potential failure of monte nuovo at ischia island southern italy numerical assessment of a likely induced tsunami and its effects on a densely inhabited area ischia is the emergent top of a large volcanic complex that rises more than 1 000 m above the sea floor at the north western end of the gulf of naples caldera resurgence in the central part of the island has resulted in the formation of differentially displaced blocks among which mt epomeo 787 m a s l is the most uplifted deformation and slope instability have been recognised as common features induced by a block resurgence mechanism that causes uplift and favours gravitational loading and flank failure the monte nuovo block a topographic high on the north western flank of mt epomeo has recently been interpreted as a block affected by deep seated gravitational slope deformation this block may undergo a catastrophic failure in the case of renewal of magmatic activity this paper investigates the potential failure of the monte nuovo block as a rockslide debris avalanche the consequent tsunami generation and wave propagation and discusses the catastrophic effects of such an event mobilization prone volume has been estimated at about 160 106 m3 and would move from a maximum elevation of 400 m a s l the landslide itself would sweep away a densely populated territory as large as 3 5 km2 the highest waves generated by the tsunami on which this paper is mainly focussed would hit the northern and western shores of ischia however the high coast would prevent inundation and limit devastation to beaches harbours and surrounding areas most of the tsunami energy would head towards the north east hitting the campania coast severe inundation would affect an area of up to 20 km2 around the mouth of the volturno river including the urban area of castel volturno in contrast less energy would travel towards the south and the gulf of naples would be perturbed by long persisting waves of limited damaging potential

spectral wave modeling in fringing reef environments abstract this study examines the implementation and validity of phase averaged spectral models in describing wave transformation over fringing reefs the wave breaking mechanism over the abrupt reef crest dissipation due to bottom friction and nonlinear energy transfer over the reef flat set the problem apart from general applications in non tropical settings the simulating wave nearshore swan model which is widely used in coastal engineering applications has embedded parameterizations of these surf zone processes for examination in addition we extend the model to include a recently implemented bottom friction source term for tropical reefs comparisons of model predictions with laboratory and field observations over fringing reefs identify promising wave breaking and bottom friction parameterizations for calibration the calibrated parameterizations enable swan to reproduce the observed wave height and setup and extend the applicability of spectral models to fringing reef environments swan however lacks the parameterization to describe the nonlinear energy transfer toward the infra gravity band that was observed in the laboratory and field studies

modeling of nonlinear wave propagation over fringing reefs abstract the applicability of existing nonlinear triad spectral models for steep slopes 0 1 0 2 characteristic of reef environments was investigated using both deterministic phase resolving and stochastic phased averaged formulations model performance was tested using laboratory observations of unidirectional wave transformation over steep and smooth bathymetry profiles the models developed for mild slopes were implemented with minimal modifications the inclusion of breaking parametrizations and linear steep slope corrections required by laboratory data the deterministic model produced typically more accurate predictions than the stochastic one but the phase averaged formulation proved fast enough to allow for an inverse modeling search for the optimal breaking parametrization the effects of the additional assumptions of the stochastic approach resulted in a slower than observed evolution of the infragravity band despite the challenge posed by the fast wave evolution and energetic breaking characteristic to the steep reef slopes both formulations performed overall well and should be considered as good provisional candidates for use in numerical investigation of wave current interaction processes on steep reefs

spectral wave dissipation over a barrier reef 1 a 2 week field experiment was conducted to measure surface wave dissipation on a barrier reef at kaneohe bay oahu hawaii wave heights and velocities were measured at several locations on the fore reef and the reef flat which were used to estimate rates of dissipation by wave breaking and bottom friction dissipation on the reef flat was found to be dominated by friction at rates that are significantly larger than those typically observed at sandy beach sites this is attributed to the rough surface generated by the reef organisms which makes the reef highly efficient at dissipating energy by bottom friction results were compared to a spectral wave friction model which showed that the variation in frictional dissipation among the different frequency components could be described using a single hydraulic roughness length scale surveys of the bottom roughness conducted on the reef flat showed that this hydraulic roughness length was comparable to the physical roughness measured at this site on the fore reef dissipation was due to the combined effect of frictional dissipation and wave breaking however in this region the magnitude of dissipation by bottom friction was comparable to wave breaking despite the existence of a well defined surf zone there under typical wave conditions the bulk of the total wave energy incident on kaneohe bay is dissipated by bottom friction not wave breaking as is often assumed for sandy beach sites and other coral reefs

extreme block and boulder transport along a cliffed coastline calicoan island philippines during super typhoon haiyan abstract this paper presents data and analysis for block and boulder transport during super typhoon haiyan along a 4 5 km long low 5 12 m cliffed coastline in calicoan island eastern samar philippines wave runup exceeding 15 2 m elevation above mean sea level drove large limestone clasts with volumes up to 83 m3 up to 280 m inland a few very large clasts with volumes 65 132 m3 were not transported by the waves when combined with recent transport reported in may et al 2015 cox et al 2016 and other literature it is becoming increasingly clear that the largest blocks transported by storms overlie much of the tsunami transport range increasing the difficulty in attributing the transport source without additional evidence comparison of present results with a global database of storm boulder transport shows a mass elevation envelope outside of which no transport is observed initiation of motion criteria were extended to include non rectangular cross sections which significantly reduces inferred velocities particularly for overturning motion these new relations were applied to the largest observed sliding and overturning boulders while considering coefficient uncertainties and resulting velocity uncertainty was large enough that direct inference of wave heights would be problematic estimates of initiation velocities for cliff edge boulders computed using lifting joint bounded relations were unreasonably large when compared to those for sliding and overturning boulders suggesting that processes other than bernoulli lift forces dominated at cliff edges

kuril islands tsunami of november 2006 1 impact at crescent city by distant scattering 1 a numerical model for the global tsunami computation constructed by kowalik et al 2005 2007a is applied to the tsunami of november 15 2006 in the northern pacific with spatial resolution of one minute numerical results are compared to sea level data collected by pacific dart buoys the tide gauge at crescent city cc recorded an initial tsunami wave of about 20 cm amplitude and a second larger energy packet arriving 2 hours later the first energy input into the cc harbor was the primary direct wave traveling over the deep waters of the north pacific interactions with submarine ridges and numerous seamounts located in the tsunami path were a larger source of tsunami energy than the direct wave travel time for these amplified energy fluxes is longer than for the direct wave prime sources for the larger fluxes at cc are interactions with koko guyot and hess rise tsunami waves travel next over the mendocino escarpment where the tsunami energy flux is concentrated owing to refraction and directed toward cc local tsunami amplification over the shelf break and shelf are important as well in many locations along the north pacific coast the first arriving signal or forerunner has lower amplitude than the main signal which often is delayed understanding this temporal distribution is important for an application to tsunami warning and prediction as a tsunami hazard mitigation tool we propose that along with the sea level records which are often quite noisy an energy flux for prediction of the delayed tsunami signals be used

extracting historic cyclone data from coastal dune deposits in eastern hainan island china abstract understanding long term large cyclone activity is critical for coastal management and disaster prevention and mitigation particularly with projected rising sea level and increasing cyclone frequency and the intensity here we present sedimentary evidence cyclone overwash deposits beachrock boulders and cyclone induced clastic deposits of historic large cyclone events from coastal dune deposits on eastern hainan island china based on luminescence dating and sedimentological analysis eight historic tropical cyclone events at 1095 90 bce 900 1000 bce 975 50 ce 1720 20 ce 1740 35 ce 1790 25 ce 1850 15 ce and 1895 10 ce have been identified in this region the elevation of the termination point of cyclone overwash deposit layers that represent the paleo cyclone minimum wave run up stage in combination with knowledge of present day cyclone events was applied to assess the intensity of these extreme events the intensity of these cyclone events was likely greater than that of cyclones in the local instrumental records furthermore these large cyclone events correspond to historic records of devastating cyclones through comparison with regional and global climate records we infer that the variability of large cyclones in the south china sea was probably modulated by the el nino southern oscillation western pacific warm pool and local sea surface temperatures over the past 3400 yr these results provide an improved understanding of long term extreme cyclone events and their response to climate change thereby contributing to regional planning and coastal defense strategies

early last interglacial ocean warming drove substantial ice mass loss from antarctica the future response of the antarctic ice sheet to rising temperatures remains highly uncertain a useful period for assessing the sensitivity of antarctica to warming is the last interglacial lig 129 to 116 ky which experienced warmer polar temperatures and higher global mean sea level gmsl 6 to 9 m relative to present day lig sea level cannot be fully explained by greenland ice sheet melt 2 m ocean thermal expansion and melting mountain glaciers 1 m suggesting substantial antarctic mass loss was initiated by warming of southern ocean waters resulting from a weakening atlantic meridional overturning circulation in response to north atlantic surface freshening here we report a blue ice record of ice sheet and environmental change from the weddell sea embayment at the periphery of the marine based west antarctic ice sheet wais which is underlain by major methane hydrate reserves constrained by a widespread volcanic horizon and supported by ancient microbial dna analyses we provide evidence for substantial mass loss across the weddell sea embayment during the lig most likely driven by ocean warming and associated with destabilization of subglacial hydrates ice sheet modeling supports this interpretation and suggests that millennial scale warming of the southern ocean could have triggered a multimeter rise in global sea levels our data indicate that antarctica is highly vulnerable to projected increases in ocean temperatures and may drive ice climate feedbacks that further amplify warming

the 2009 samoa tonga great earthquake triggered doublet great earthquakes having seismic magnitudes of at least 8 usually involve abrupt sliding of rock masses at a boundary between tectonic plates such interplate ruptures produce dynamic and static stress changes that can activate nearby intraplate aftershocks as is commonly observed in the trench slope region seaward of a great subduction zone thrust event1 the earthquake sequence addressed here involves a rare instance in which a great trench slope intraplate earthquake triggered extensive interplate faulting reversing the typical pattern and broadly expanding the seismic and tsunami hazard on 29 september 2009 within two minutes of the initiation of a normal faulting event with moment magnitude 8 1 in the outer trench slope at the northern end of the tonga subduction zone two major interplate underthrusting subevents both with moment magnitude 7 8 with total moment equal to a second great earthquake of moment magnitude 8 0 ruptured the nearby subduction zone megathrust the collective faulting produced tsunami waves with localized regions of about 12 metres run up that claimed 192 lives in samoa american samoa and tonga overlap of the seismic signals obscured the fact that distinct faults separated by more than 50 km had ruptured with different geometries with the triggered thrust faulting only being revealed by detailed seismic wave analyses extensive interplate and intraplate aftershock activity was activated over a large region of the northern tonga subduction zone

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

identification and classification of very low frequency waves on a coral reef flat very low frequency vlf 0 001 0 005 hz waves are important drivers of flooding of low lying coral reef islands in particular vlf wave resonance is known to drive large wave runup and subsequent overwash using a five month dataset of water levels and waves collected along a cross reef transect on roi namur island in the republic of the marshall islands the observed vlf motions were categorized into four different classes 1 resonant 2 non resonant standing 3 progressive growing and 4 progressive dissipative waves each vlf class is set by the reef flat water depth and in the case of resonance the incident band offshore wave period using an improved method to identify vlf wave resonance we find that vlf wave resonance caused prolonged 0 5 6 0 hr large amplitude water surface oscillations at the inner reef flat ranging in wave height from 0 14 to 0 83 m it was induced by relatively long period grouped incident band waves and occurred under both storm and non storm conditions moreover observed resonant vlf waves had non linear bore like wave shapes which likely have a larger impact on the shoreline than regular sinusoidal waveforms as an alternative technique to the commonly used fast fourier transformation we propose the hilbert huang transformation that is more computationally expensive but can capture the wave shape more accurately this research demonstrates that understanding vlf waves on reef flats is important for evaluating coastal flooding hazards this article is protected by copyright all rights reserved

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

periglacial features in patriot hills ellsworth mountains antarctica abstract this work describes periglacial features identified at patriot hills at the southernmost part of ellsworth mountains antarctica during the 2008 2009 brazilian antarctic expedition and discusses their morphogenetic environment identified periglacial features were classified into a rock glacier like landform b slightly creeping debris mantled slopes c steep debris mantled slopes and d rock falls results obtained from sediment sample analysis suggest activity and passive movement of a rock glacier like landform albeit minimal wind seems to play an important role in patriot hills local geomorphology periglacial features such as slightly creeping debris mantled slope appear to have preferred slope orientation they are commonly found onto slopes where the katabatic wind flows down slopewash and groundwater movement processes may be limited or non existent since most snow disappears through sublimation

wave set up on coral reefs 2 set up on reefs with various profiles abstract all available laboratory data for wave set up on two dimensional reef profiles of various shapes have been compared with data from an idealised horizontal reef with a steep reef face gourlay 1996 the data is generally well represented by a relationship between the relative set up parameter gh r t o and the submergence parameter g h r h r h o and the relative set up on reef profiles of natural form is found to be less than that observed on the idealised horizontal reef the important influences of reef rim slope and variable water depths on the reef top have been investigated and some methods for allowing for them are suggested comparison of data for irregular waves with that for regular waves has led to the development of a simple method for estimating the effects of wave groups upon the magnitude of the steady state mean wave set up gh r the results of the analyses are applied to the determination of wave set up and its effects at three specific coral reef sites

the role of near shore bathymetry during tsunami inundation in a reef island setting a case study of tutuila island on september 29 2009 at 17 48 utc an mw 8 1 earthquake in the tonga trench generated a tsunami that caused heavy damage across samoa american samoa and tonga one of the worst hits was the volcanic island of tutuila in american samoa tutuila has a typical tropical island bathymetry setting influenced by coral reefs and so the event provided an opportunity to evaluate the relationship between tsunami dynamics and the bathymetry in that typical island environment previous work has come to differing conclusions regarding how coral reefs affect tsunami dynamics through their influence on bathymetry and dissipation this study presents numerical simulations of this event with a focus on two main issues first how roughness variations affect tsunami run up and whether different values of manning s roughness parameter n improve the simulated run up compared to observations and second how depth variations in the shelf bathymetry with coral reefs control run up and inundation on the island coastlines they shield we find that no single value of n provides a uniformly good match to all observations and we find substantial bay to bay variations in the impact of varying n the results suggest that there are aspects of tsunami wave dissipation which are not captured by a simplified drag formulation used in shallow water waves model the study also suggests that the primary impact of removing the near shore bathymetry in coral reef environment is to reduce run up from which we conclude that at least in this setting the impact of the near shore bathymetry is to increase run up and inundation

shock capturing boussinesq type model for nearshore wave processes this paper describes the formulation and validation of a nearshore wave model for tropical coastal environment the governing boussinesq type equations include the conservative form of the nonlinear shallow water equations for shock capturing a riemann solver supplies the inter cell flux and bathymetry source term while a godunov type scheme integrates the evolution variables in time the model handles wave breaking through momentum conservation with energy dissipation based on an eddy viscosity concept the computed results show very good agreement with laboratory data for wave propagation over a submerged bar wave breaking and runup on plane beaches as well as wave transformation over fringing reefs the model accurately describes transition between supercritical and subcritical flows as well as development of dispersive waves in the processes

combined infragravity wave and sea swell runup over fringing reefs by super typhoon haiyan super typhoon haiyan struck the philippines on 8 november 2013 marking one of the strongest typhoons at landfall in recorded history extreme storm waves attacked the pacific coast of eastern samar where the violent typhoon first made landfall our field survey confirmed that storm overwash heights of 6 14 m above mean sea level were distributed along the southeastern coast and extensive inundation occurred in some coastal villages in spite of natural protection by wide fringing reefs a wave model based on boussinesq type equations is constructed to simulate wave transformation over shallow fringing reefs and validated against existing laboratory data wave propagation and runup on the eastern samar coast are then reproduced using offshore boundary conditions based on a wave hindcast the model results suggest that extreme waves on the shore are characterized as a superposition of the infragravity wave and sea swell components the balance of the two components is strongly affected by the reef width and beach slope through wave breaking frictional dissipation reef flat resonances and resonant runup amplification therefore flood characteristics significantly differ from site to site due to a large variation of the two topographic parameters on the hilly coast strong coupling of infragravity waves and sea swells produces extreme runup on steep beaches fronted by narrow reefs whereas the infragravity waves become dominant over wide reefs and they evolve into bores on steep beaches

wave breaking hydrodynamics within coral reef systems and the effect of changing relative sea level this paper considers the hydrodynamics of wave driven flow across a coral reef and the resultant flushing of its lagoon current depth coefficients are introduced that describe the fractional change of across reef and lagoonal current with change in the relative local sea level i e the depth of water over the reef flat the coefficients are derived from an analytical hydrodynamic model and compared with data from two reefs the first is ningaloo reef in northwest australia which is a typical barrier reef with a narrow coastal lagoon and the second is kaneohe bay in oahu hawaii where the reef is both unusually deep and wide the current depth coefficients are shown to be sensitive to the form of the frictional law on the reef flat and can be deduced from measurements of the astronomical tidal currents in the lagoon both quadratic and linear friction laws are considered for the reef flat and good agreement obtained with a linear law based on the high frequency motion due to surface gravity waves

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

wave transformation on a coral reef wave transformation of regular waves was measured in a laboratory model of a fringing reef with a steep face and an outer reef top slope gradually decreasing in the landward direction data was obtained for various wave conditions and water levels a nonlinearity parameter fco g1 25ho 0 5t2 5 hc 1 75 based upon one proposed by swart and loubser 1979 is proposed as a suitable parameter for classifying wave transformation regimes on this reef in particular when fco 150 waves plunge on the reef edge and the amount of wave energy reaching a shore or structure is small 16 when fin co 100 waves spill on the reef top but the greater part of their energy is transmitted over the reef top the maximum values of the wave height to water depth ratio on the reef top were found to be consistent with nelson s analyses for laboratory and field data which indicate that the maximum stable wave height to depth ratio h d on a horizontal bottom never exceeds 0 55 for shallow water waves fc 500 the experimental data confirms that the maximum value of h d decreases when fc decreases but that it also increases when the bottom slope increases

transport properties of high albite crystals near endmember feldspar and pyroxene glasses and their melts to high temperature thermal diffusivity d was measured using laser flash analysis lfa from oriented single crystal albite and glasses near lialsi3o8 naalsi3o8 caal2si2o8 lialsi2o6 and camgsi2o6 compositions viscosity measurements of the supercooled liquids over 2 6 108 to 8 9 1012 pa s confirm strongly non arrhenian behavior for caal2si2o8 and camgsi2o6 and near arrhenian behavior for the others as t increases d glass decreases approaching a constant near 1 000 k upon crossing the glass transition d decreases rapidly for feldspars d for the melt is 15 below d of the bulk crystal whereas for pyroxenes this difference is 40 thermal conductivity k lat c p d of crystals decreases with increasing t but k lat of glasses increases with t because heat capacity c p increases with t more strongly than density and d decrease for feldspars k lat for the melt is 10 below that of the bulk crystal or glass whereas this decrease for pyroxene is 50 therefore melting substantially impedes heat transport providing positive thermal feedback that could promote further melting

maximum overtopping forces on a dike mounted wall with a shallow foreshore abstract the impact force induced by waves overtopping a dike with a vertical wall on its crest and with a shallow foreshore seaward of the dike was studied to this end physical model tests were performed in a wave flume at a typical scale of 1 25 the goal of this study was to develop a method to estimate the maximum forces on the wall during a known storm peak the time series of water depth at toe of the dike flow thickness at seaward edge of the dike crest and impact forces were measured an empirical generalized pareto distribution is verified as the best distribution for the extreme overtopping wave forces

bedmap a new ice thickness and subglacial topographic model of antarctica measurements of ice thickness on the antarctic ice sheet collected during surveys undertaken over the past 50 years have been brought together into a single database from these data a seamless suite of digital topographic models have been compiled for antarctica and its surrounding ocean this includes grids of ice sheet thickness over the grounded ice sheet and ice shelves water column thickness beneath the floating ice shelves bed elevation beneath the grounded ice sheet and bathymetry to 60 s including the sub ice shelf cavities these grids are consistent with a recent high resolution surface elevation model of antarctica while the digital models have a nominal spatial resolution of 5 km such high resolution is justified by the original data density only over a few parts of the ice sheet the suite does however provide an unparalleled vision of the geosphere beneath the ice sheet and a more reliable basis for ice sheet modeling than earlier maps the total volume of the antarctic ice sheet calculated from the bedmap grid is 25 4 million km3 and the total sea level equivalent derived from the amount of ice contained within the grounded ice sheet is 57 m comprising 52 m from the east antarctic ice sheet and 5 m from the west antarctic ice sheet slightly less than earlier estimates the gridded data sets can be obtained from the authors

on the glaciological meteorological and climatological significance of antarctic blue ice areas this paper presents the current state of our knowledge about antarctic blue ice areas scattered widely over the antarctic continent yet covering only approximately 1 of its surface area blue ice areas have some peculiar characteristics that make them of particular interest for planetary geologists glaciologists meteorologists and climatologists for instance blue ice areas are subject to net ablation mainly by sublimation since any accumulation is easily swept off their smooth surfaces by winds moreover they are significantly warmer than their surroundings and the wind over them is generally more gusty an important feature of blue ice is its relatively low albedo 0 56 compared with that of snow 0 80 blue ice is probably considerably smoother than snow in the aerodynamic sense with roughness lengths as low as 3 10 6 m which indicates that blue ice is probably the only permanent natural surface over which the air flow is mainly in the aerodynamic smooth regime further since it is likely that very old ice is exposed at the surface of some blue ice areas this ice would be of great interest for paleoclimatic studies it has also been suggested that blue ice areas are sensitive to climate change this would make them useful as antarctic climate indicators because they can easily be monitored by satellite finally this paper addresses several gaps in our knowledge about blue ice areas and gives suggestions for future blue ice area research

the finite kinematic rupture properties of great sized earthquakes since 1990 abstract here i present a database of 160 finite fault models for all earthquakes of m 7 5 and above since 1990 created using a consistent modeling approach the use of a common approach facilitates easier comparisons between models and reduces uncertainties that arise when comparing models generated by different authors data sets and modeling techniques i use this database to verify published scaling relationships and for the first time show a clear and intriguing relationship between maximum potency the product of slip and area and average potency for a given earthquake this relationship implies that earthquakes do not reach the potential size given by the tectonic load of a fault sometimes called moment deficit calculated via a plate rate over time since the last earthquake multiplied by geodetic fault coupling instead average potency or slip scales with but is less than maximum potency dictated by tectonic loading importantly this relationship facilitates a more accurate assessment of maximum earthquake size for a given fault segment and thus has implications for long term hazard assessments the relationship also suggests earthquake cycles may not completely reset after a large earthquake and thus repeat rates of such events may appear shorter than is expected from tectonic loading this in turn may help explain the phenomenon of earthquake super cycles observed in some global subduction zones

reply to comment on supercooled diopside melt confirmation of temperature dependent expansivity using container based dilatometry by j gottsmann and d b dingwell

a modal decomposition method for the analysis of long waves amplification at coastal areas abstract this paper presents a model for the evaluation of long waves amplification at coastal areas based on a modal decomposition method it is able of modelling the growth and the decay of the natural modes of the area under investigation and their contribution to the total wave field the model is an improvement of that developed by bellotti et al 2012b that was able of calculating the frequencies and the shapes of the natural modes but not their amplification under the action of forcing waves three test cases are used for the validation and to show the capabilities of the model the first considers the long waves resonance into a long and narrow harbour bay over a constant water depth it is a case for which a high degree of wave trapping into the semi enclosed coastal area is induced by the specific shape of the coastline the second test deals with the propagation of a group of edge waves along a straight coast with a constant sloping bottom generated in proximity of the shoreline by a special wave maker the model in this case properly evaluates what are the edge waves modes that contribute to the total wave field the third case involves the interaction of a solitary wave with a conical island for which laboratory data are available in this test a low degree of trapping exists but it is interesting for the present aims as the propagation of the waves around the island is expected to occur under the form of wave modes partially trapped by the bathymetry i e edge waves excited by the transient wave arriving from offshore on the basis of the tests results it is shown what is the role of the more relevant natural modes in the formation of the total surface elevation

hydrostatic versus non hydrostatic modeling of tsunamis with implications for insular shelf and reef environments abstract dispersion is known to separate frequency components and reduce the amplitude of tsunami waves in the open ocean the present paper elucidates a reverse process in which the dispersed wave components from trans oceanic propagation of the 2011 tohoku tsunami regroup over the insular shelves and reefs of hawaii the non hydrostatic and hydrostatic modes of a nonlinear long wave model describe the pertinent processes with and without dispersion using the same system of two way nested grids for direct comparison both solutions have very similar amplitude spectra across the ocean and reproduce the dominant components of recorded surface elevations and currents in hawaii despite their markedly different offshore waveforms the hydrostatic solution shows early arrival of short period signals from nonlinear scattering around the hawaiian islands and faster attenuation of the amplitude due to their local source the short period trailing waves from dispersion more effectively excite shelf and reef oscillations giving rise to better agreement with both the amplitude and phase of the recorded data even with larger offshore wave amplitude a hydrostatic model trends to underestimate the surge elevation and current velocity at coastlines fronted by shallow reefs susceptible to resonance oscillations associated with edge waves

wave set up on coral reefs 1 set up and wave generated flow on an idealised two dimensional horizontal reef wave set up may be significant in determining water levels on coral reefs particularly in microtidal environments and hence is an important factor for the design of reef top structures and for the stability of reef top islands laboratory experiments have been made on a two dimensional model of an idealised horizontal reef under two different conditions corresponding to a fringing reef or closed lagoon situation and a platform reef or open lagoon situation both wave set up on the reef top and the wave generated flow across the reef were measured and related to wave and tide level conditions all other factors being the same wave set up is greatest at low tide levels whereas wave generated flow is greater at higher tide levels the magnitude of the set up on a platform reef with a wave generated flow is less than on a fringing reef without any net flow by an amount equal to the velocity head of the flow across the reef dimensionless parameters ghrt o and q gho3 are found to be functions of relative submergence parameters hrho or r hr ho for values of ghr hr ho 1 waves break on the reef top and radiation stress theory can be used to calculate set up for ghr hr ho 0 7 waves break on the reef face and set up is determined by broadcrested weir control at the reef edge the symbols are defined as follows g is gravitational acceleration hr is still water depth over horizontal reef top ho is offreef wave height equivalent deep water value q is discharge per unit length of reef edge t is wave period and ghr is maximum wave set up on reef top

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

do blue ice moraines in the heritage range show the west antarctic ice sheet survived the last interglacial abstract we present a hypothesis that best explains cosmogenic isotope data on blue ice moraines in the heritage range west antarctica the age of the moraines implies that they and the related ice sheet surface with which they are associated have persisted on the flanks of nunataks throughout at least the last interglacial glacial cycle the implication is that although the west antarctic ice sheet wais may have fluctuated in thickness during glacial cycles the central dome has remained intact for at least 200 kyr and possibly even for 400 kyr such a finding if substantiated would contribute to our understanding of the sensitivity of the wais to climate change further it would be a powerful geomorphic constraint on models of the past behaviour of the ice sheet during glacial cycles and thus those predicting the future of the ice sheet in a warming world

glaciological investigations on union glacier ellsworth mountains west antarctica union glacier west antarctica was intensively mapped in december 2008 when an over snow traverse was conducted by cecs and ale with the aim to determine the ice dynamical characteristics of the glacier through mapping the crevasse fields and by providing a glaciological baseline for future studies a mean ice thickness of 1450 m was measured confirming the presence of a deep subglacial topography 900 m below sea level much deeper than previously estimated ice velocities were also measured at 21 stakes drilled into the ice at the narrowest gate of the glacier between december 2007 and december 2008 yielding a mean value of 22 6 m a 1 these velocities combined with the measured ice thicknesses and a numerical model yielded an ice flux of 0 10 0 03 km 3 a 1 w e considering the ice basin above this gate a mean surface mass balance of 0 18 0 05 m a 1 was estimated a value consistent with a mean snow accumulation for nearby ice streams these values indicate that the glacier is at present near equilibrium

the million year evolution of the glacial trimline in the southernmost ellsworth mountains antarctica an elevated erosional trimline in the heart of west antarctica in the ellsworth mountains tells of thicker ice in the past and represents an important yet ambiguous stage in the evolution of the antarctic ice sheet here we analyse the geomorphology of massifs in the southernmost heritage range where the surfaces associated with the trimline are overlain by surficial deposits that have the potential to be dated through cosmogenic nuclide analysis analysis of 100 rock samples reveals that some clasts have been exposed on glacially moulded surfaces for 1 4 ma and perhaps more than 3 5 ma while others reflect fluctuations in thickness during quaternary glacial cycles modelling the age of the glacially moulded bedrock surface based on cosmogenic 10be 26al and 21ne concentrations from a depth profile indicates a minimum exposure age of 2 1 2 6 ma we conclude that the glacially eroded surfaces adjacent to the trimline predate the last glacial maximum and indeed the quaternary since erosion was by warm based ice near an ice sheet upper margin we suggest it first occurred during the early glaciations of antarctica before the stepped cooling of the mid miocene at 14 ma this was a time when the interior antarctic continent had summers warm enough for tundra vegetation to grow and for mountain glaciers to consist of ice at the pressure melting point during these milder conditions and subsequently erosion of glacial troughs is likely to have lowered the ice sheet surface in relation to the mountains this means that the range of orbitally induced cyclic fluctuations in ice thickness have progressively been confined to lower elevations

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

late pleistocene and early holocene change in the weddell sea a new climate record from the patriot hills ellsworth mountains west antarctica the transition from the late pleistocene to the holocene 30 000 5000 years ago was a period of considerable climate variability which has been associated with changes in deep water formation and the intensity of the meridional overturning circulation although numerous records exist across the north atlantic region few antarctic ice core records have been obtained from the south here we exploit the potential of upwelling ancient ice so called blue ice areas bias from the patriot hills in the ellsworth mountains to derive the first deuterium isotope record d from continental antarctica south of the weddell sea gas analysis and glaciological considerations provide a first relative chronology inferred temperature trends from the patriot hills bia and snow pit suggest changing climate influences during the transition between the last glacial period and holocene under modern conditions the interplay between the antarctic high pressure system and the southern annular mode appears to play a significant role in controlling katabatic wind flow over the site while the bia record suggests that greater sea ice extent during the last glacial period was a major control our results demonstrate the considerable potential of the patriot hills site for reconstructing past climate change in the south atlantic region

tsunami and shelf resonance on the northern chile coast this work presents the analysis of long waves resonance in two of the main cities along the northern coast of chile arica and iquique where a large tsunamigenic potential remains despite recent earthquakes by combining a modal analysis solving the equation of free surface oscillations with the analysis of background spectra derived from in situ measurements the spatial and temporal structures of the modes are recovered comparison with spectra from three tsunamis of different characteristics shows that the modes found have been excited by past events moreover the two locations show different response patterns arica is more sensitive to the characteristics of the tsunami source whereas iquique shows a smaller dependency and similar response for different tsunami events results are further compared with other methodologies with good agreement these findings are relevant in characterizing the tsunami hazard in the area and the methodology can be further extended to other regions along the chilean coast

predicting the hydrodynamic response of a coastal reef lagoon system to a tropical cyclone using phase averaged and surfbeat resolving wave models abstract tropical cyclone tc olwyn travelled along the coast of ningaloo reef in northwestern australia as a category 3 tc during 12 13 march 2015 with sustained wind speeds of over 130 km h 1 and significant wave heights on the forereef reaching 6 m observations from tc olwyn showed that contrary to typical wave transformation patterns across a coastal reef lagoon under the tc conditions there was a substantial shoreward increase of wave height this unusual pattern was primarily due to strong local wind wave generation under the extreme wind conditions despite the lagoon itself being relatively small order 1 km wide and shallow order 1 m depth two common types of coastal numerical wave models that include either wave growth i e the phase averaged model swan or infragravity waves i e the surfbeat resolving model xbeach but not both processes were used to assess the capabilities of numerical models to predict the cyclone induced hydrodynamics model results showed that wave conditions in the lagoon and at the shoreline were dominated by locally generated wind waves with the reef efficiently dissipating the large incident waves offshore the infragravity waves in the lagoon were only of secondary importance during the tc compared to the locally generated sea swell waves although both the phase averaged swan and surfbeat resolving xbeach models were able to predict some of the local hydrodynamic responses for this specific site and storm the use of a phase averaged model yielded the most accurate predictions of the hydrodynamics given that it included wind wave growth however because the influence of infragravity waves cannot be neglected in reef environments in general these results emphasize the need for a more general modeling approach that requires the addition of wind wave growth formulations into surfbeat or fully phase resolving classes of numerical wave models and or the addition of an infragravity wave formulation in spectral wave models

coastal flooding and the 1861 2 california storm season abstract a series of large storms attributed to atmospheric river conditions struck the california coast in the winter of 1861 2 although historical accounts document inland flooding little is known about how the 1861 2 storms impacted the now heavily developed california coast here we show that the 1861 2 storms emplaced a deposit of beach sand up to 50 cm thick over 450 m inland within a southern california salt marsh this deposit is unprecedented in the post european sediments of the marsh and more extensive than that derived from any other historical event it is comparable in scale to hurricane and tsunami washover fans in back barrier environments along other coastlines the presence of overwash deposits in carpinteria suggests that the 1861 2 storm season was erosive enough to remove coastal barriers allowing for inundation of parts of the coastline currently developed efforts to prepare for a recurrence of an 1861 2 like storm season should address potential coastal impacts likewise interpretations of past washover deposits should consider these unusually prolonged stormy periods in addition to hurricane and tsunami inundation

elevation change and ice flow at horseshoe valley patriot hills west antarctica patriot hills is located at 80 18 s 81 22 w at the southernmost end of the heritage range ellsworth mountains west antarctica a comparison of glacier elevation data and ice velocities obtained by the differential global positioning system in the period 1996 97 is presented ablation accumulation rates measured at a network of stakes in horseshoe valley show average accumulation of 70 kg m 2 a 1 in the central part of the valley and a maximum ablation of 170 kg m 2 a 1 at the edge of the blue ice area close to patriot hills changes in the surface elevation of the glacier measured at 81 stakes in the period 1995 97 show a mean thickening of 0 43 0 42 m a 1 which considering the uncertainties indicates that the ice sheet around patriot hills is in near steady state surface velocities in combination with ice thicknesses obtained by ground based radio echo sounding are used to compute the ice flux across the horseshoe valley transect a total outflow of 0 44 0 08 km 3 a 1 is obtained considering a catchment area for horseshoe valley of 1087 km 2 upstream from the flow transect and a net accumulation rate of 100 kg m 2 a 1 a total input of 0 11 0 04 km 3 a 1 by snow accumulation is obtained accepting a near equilibrium condition for the ice sheet the flux difference i e 0 33 km 3 a 1 must be supplied by flow from the inland ice sheet through ice cliffs located in mountain gaps in the heritage range if horseshoe valley is not in steady state but is thickening the positive mass balance could be due to increased snow accumulation or enhanced ice flow from the interior of the ice sheet new data are needed to elucidate this

airborne radar sounder for temperate ice initial results from patagonia we describe the development of a low frequency airborne radar specifically designed for the sounding of temperate ice the system operates at a central frequency of 1 mhz and consists of an impulse transmitter with an output voltage up to 5000 v and a digital receiver with a maximum gain of 80 db the radar was deployed on board a casa 212 aircraft which also carries a laser altimeter an inertial navigation system a digital camera and a gps receiver a description of the radar system is provided as well as preliminary results obtained at glaciar tyndall campo de hielo sur southern patagonia icefield where an ice depth of 670 m was reached

resonance in hawaii waters from the 2006 kuril islands tsunami 1 the 2006 kuril islands tsunami while not destructive to coastal properties resulted in prolonged oscillations in hawaii waters this study examines the oscillation patterns and amplification through reconstruction of the tsunami using a nonlinear shallow water model after validation with water level measurements a fast fourier transform of the computed surface elevation reveals profound oscillation modes at various periods around the hawaiian islands the oscillation at the regional scale consists of standing waves across the island chain and resonance in interconnected channels embayments and shallow shelves resonance in embayments and standing edge waves dominate the oscillation in coastal waters the results show strong correlation between bathymetric features and resonance oscillations and identify tsunami hazard areas for planning and emergency management

antarctic blue ice moraines analogue for northern hemisphere ice sheets abstract this paper reviews the distribution character and age of blue ice moraines in antarctica and asks whether there are implications for the study of former pleistocene ice sheets in the northern hemisphere blue ice forms where acceleration of downslope katabatic winds removes snow and causes ice to ablate upward ice flow compensates for the surface ablation and in some places brings rock debris to the surface to form a blue ice moraine blue ice moraines occur where topography focuses katabatic winds notably outlet glaciers cutting through mountains and in the lee of nunataks and escarpments nearer the coast many antarctic blue ice moraines have been accumulating for millions of years the cyclic growth and decay of pleistocene ice sheets and the dominance of surface ablation near the ice sheet margins are clearly different yet there are aspects that apply to pleistocene ice sheets based on antarctic blue ice deposits equivalent deposits associated with former pleistocene ice sheets are likely to 1 lie in topographic sediment traps such as in side valleys or embayments next to outlet glaciers 2 occur in the lee of mountains 3 display a morphology indicating ice flow into the embayment or towards the mountain front 4 include a wide range of lithologies derived from the inland ice sheet yet consist wholly of local debris in places 5 accumulate a thick deposit perhaps over successive glaciations further 6 the location and intensity of moraine formation will change spatially and vertically in response to changes in the relative elevation of the surrounding mountains and its effect on ice flow the extent to which these criteria will help in interpreting the behaviour of pleistocene ice sheets is uncertain but we use examples from the greenland laurentide and eurasian ice sheets to suggest that the concept of enhanced ablation by katabatic winds encouraging surface moraine formation helps resolve several puzzles

wavenumber frequency analysis of the landslide generated tsunamis at a conical island abstract in this paper we investigate the propagation of tsunamis generated by landslides around the coast of an island to understand the propagation and trapping mechanisms of the waves records of shoreline displacement have been processed using the wavenumber frequency analysis k f we identify the dispersion relation followed by the waves that propagate alongshore it appears that the 0th order edge wave mode is the only one relevant for shoreline run up furthermore it is shown that the edge wave dispersion relation is a quantitative tool to estimate the phase and group wave celerities a very good agreement is found when comparing the wave celerities as calculated from the experimental records against those predicted by the edge wave theory furthermore the analysis of the tsunami around the island has been carried out by means of the two dimensional k f using as input data a high space resolution dataset of free surface elevations it is found that other modes both trapped 1st order edge waves and non trapped free radiating waves occur during the propagation

mass balance of polar ice sheets recent advances in the determination of the mass balance of polar ice sheets show that the greenland ice sheet is losing mass by near coastal thinning and that the west antarctic ice sheet with thickening in the west and thinning in the north is probably thinning overall the mass imbalance of the east antarctic ice sheet is likely to be small but even its sign cannot yet be determined large sectors of ice in southeast greenland the amundsen sea embayment of west antarctica and the antarctic peninsula are changing quite rapidly as a result of processes not yet understood

resonance and impact of the 2009 samoa tsunami around tutuila american samoa 1 the 2009 samoa tsunami resulted in severe damage and inundation at tutuila american samoa the disparity of the impact and the varying accounts of the tsunami along the coast remain one of the most intriguing aspects of the event we utilize a dispersive wave model to reconstruct the tsunami from the earthquake source for understanding of the wave dynamics around tutuila after validation with water level measurements a fast fourier transform of the computed surface elevation reveals coupled resonance oscillations between 3 and 18 min period over the insular slope and shelf as well as the fringing reefs the resonance which focuses energy according to shelf and embayment configurations provides an explanation of the runup data and eyewitness accounts and identifies the coastal communities prone to tsunami hazards

boussinesq type model for energetic breaking waves in fringing reef environments abstract the steep offshore slope and abrupt transition to a shallow lagoon are conducive to formation of energetic breaking waves in fringing reef environments this paper describes an extension of a one dimensional shock capturing boussinesq type model to account for these processes in two dimensions and the numerical formulation to facilitate adaptive time integration and code parallelization the governing equations contain the conservative form of the nonlinear shallow water equations to capture shock related hydraulic processes the finite volume method with a godunov type scheme provides a compatible conservative numerical procedure a two dimensional tvd total variation diminishing reconstruction procedure evaluates the flow variables on either side of the cell interface while a riemann solver supplies the flux and bathymetry source terms at the interface a well balanced scheme eliminates depth interpolation errors in the domain and preserves continuity across moving boundaries over irregular topography time integration of the governing equations evaluates the conserved variables which in turn provide the horizontal velocity components through systems of linear equations corresponding to series of one dimensional problems the application of the model to fringing reef environments is validated with laboratory experiments performed at oregon state university as well as field data collected in hawaii the model describes the flux dominated wave breaking processes through the riemann solver without predefined empirical energy dissipation and reproduces transitions between sub and supercritical flows as well as development of dispersive and infra gravity waves in the processes

supercooled diopside melt confirmation of temperature dependent expansivity using container based dilatometry the expansivity of supercooled diopside liquid has been determined using techniques of container based dilatometry two thermal strategies have been employed one in which the sample is brought to volumetric equilibrium by long duration dwells at low temperatures 817 c and one in which scanning dilatometry of the sample has been performed at somewhat higher temperatures 890 913 c the results of both experiments yield a supercooled liquid expansivity for diopside liquid in the temperature range of 817 913 c of 84 4 2 8 10 4 cm3 mol k the expansivity is 65 higher than that obtained for diopside melt obtained at superliquidus temperatures using the double bob archimedean method combined fitting of the new low temperature volume temperature data from the present study and the superliquidus data from the literature has been performed the combined fit yields the following equations for the volume temperature relationship of diopside liquid t temperature in c