iron control of past productivity in the coastal upwelling system off the atacama desert chile 1 biogenic opal and organic carbon vertical rain rates in sediment cores reveal a strong cyclicity in the productivity of the upwelling system off presently arid northern chile during the last 100 000 years changes in productivity are found to be in phase with the precessional cycle 20 000 years and with inputs of iron from the continent during austral summer insolation maxima increased precipitation and river runoff in the region appear to have brought high inputs of iron mainly from the andes to the coastal ocean enhancing primary productivity there we interpret our results as providing evidence for iron control of past productivity in this upwelling system and for a tight link between productivity and orbital forcing at midlatitudes

holocene rainfall variability in southern chile a marine record of latitudinal shifts of the southern westerlies geochemical and clay mineral parameters of a high accumulation marine sediment core from the chilean continental slope 41 s provide a 7700 yr record of rainfall variability in southern chile related to the position of the southern westerlies we especially use the iron content measured with a time resolution of ca 10 yr on average of 14 caccelerator mass spectrometry dated marine sediments as a proxy for the relative input of iron poor coastal range and iron rich andean source rocks variations in this input are most likely induced by rainfall changes in the continental hinterland of the core position based on these interpretations we find a pronounced rainfall variability on multicentennial to millennial time scales superimposed on generally more arid conditions during the middle holocene 7700 to 4000 cal yr b p compared to the late holocene 4000 to present this variability and thus changes in the position of the southern westerlies are first compared to regional terrestrial paleoclimate data sets from central and southern chile in order to derive possible wider implications and forcing mechanisms of the holocene latitudinal shifts of the southern westerlies we then compare our data to ice core records from both tropical south america and coastal antarctica these records show similar bands of variability centered at ca 900 and 1500 yr comparisons of band pass filters suggest a close connection of shifts of the southern westerlies to changes within the tropical climate system the correlation to climate conditions in coastal antarctica shows a more complicated picture with a phase shift at the beginning of the late holocene coinciding with the onset of the modern state of el nin o southern oscillation system the presented data provide further evidence that the well known millennial scale climate variability during the last glacial continued throughout the holocene fl 2001 elsevier science b v all rights reserved

sequential extraction of iron in marine sediments from the chilean continental margin iron content of the bulk marine sediment from the chilean continental margin has been used to infer millenial scale climate changes in southeast pacific lamy f klump j hebbeln d wefer g 2000 rapid climate change in northern chile over the last 80 ka recorded in a marine sediment core terra nova 12 8 13 changes of iron contents have been related to a varying contribution of andean fe rich versus coastal range fe poor source rocks ultimately controlled by continental rainfall changes however variations observed could also be produced by changes in the proportions of two components in the sediment a detrital component with low and constant fe content and an authigenic phase fe oxide pyrite apatite etc with high fe content a sequential extraction has been used to partition the total iron content in the sediment of core geob 7101 at the continental margin of chile the extraction steps included five fractions exchangeable bound to carbonates bound to fe mn oxides bound to organic matter and residual iron appeared to be mainly present in the residual fraction i e in the detrital component our study indicates that total fe or fe al may be used to infer millenial scales climate changes in the southeastern pacific

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

time dependent onshore tsunami response abstract while bulk measures of the onshore impact of a tsunami including the maximum run up elevation and inundation distance are important for hazard planning the temporal evolution of the onshore flow dynamics likely controls the extent of the onshore destruction and the erosion and deposition of sediment that occurs however the time varying dynamics of actual tsunamis are even more difficult to measure in situ than the bulk parameters here a numerical model based on the non linear shallow water equations is used to examine the effects variations in the wave characteristics bed slope and bottom roughness have on the temporal evolution of the onshore flow model results indicate that the onshore flow dynamics vary significantly over the parameter space examined for example the flow dynamics over steep smooth morphologies tend to be temporally symmetric with similar magnitude velocities generated during the run up and run down phases of inundation conversely on shallow rough onshore topographies the flow dynamics tend to be temporally skewed toward the run down phase of inundation with the magnitude of the flow velocities during run up and run down being significantly different furthermore for near breaking tsunami waves inundating over steep topography the flow velocity tends to accelerate almost instantaneously to a maximum and then decrease monotonically conversely when very long waves inundate over shallow topography the flow accelerates more slowly and can remain steady for a period of time before beginning to decelerate these results indicate that a single set of assumptions concerning the onshore flow dynamics cannot be applied to all tsunamis and site specific analyses may be required

implications of the 26 december 2004 sumatra andaman earthquake on tsunami forecast and assessment models for great subduction zone earthquakes results from different tsunami forecasting and hazard assessment mod els are compared with observed tsunami wave heights from the 26 december 2004 indian ocean tsunami forecast models are based on initial earthquake information and are used to estimate tsunami wave heights during propagation an empirical forecast relationship based only on seismic moment provides a close estimate to the observed mean regional and maximum local tsunami runup heights for the 2004 indian ocean tsunami but underestimates mean regional tsunami heights at azimuths in line with the tsunami beaming pattern e g sri lanka thailand standard forecast models developed from subfault discretization of earthquake rupture in which deep ocean sea level observations are used to constrain slip are also tested forecast models of this type use tsunami time series measurements at points in the deep ocean as a proxy for the 2004 indian ocean tsunami a transect of deep ocean tsunami amplitudes recorded by satellite altimetry is used to constrain slip along four subfaults of the m 9 sumatra andaman earthquake this proxy model performs well in comparison to observed tsunami wave heights travel times and inundation patterns at banda aceh hypothetical tsunami hazard assessments models based on end member estimates for average slip and rupture length m w 9 0 9 3 are compared with tsunami observations using average slip low end member and rupture length high end member m w 9 14 consistent with many seismic geodetic and tsunami inversions adequately estimates tsunami runup in most regions except the extreme runup in the western aceh province the high slip that occurred in the southern part of the rupture zone linked to runup in this location is a larger fluctuation than expected from standard stochastic slip models in addition excess moment release 9 deduced from geodetic studies in comparison to seismic moment estimates may gen erate additional tsunami energy if the exponential time constant of slip is less than approximately 1 hr overall there is significant variation in assessed runup heights caused by quantifiable uncertainty in both first order source parameters e g rupture length slip length scaling and spatiotemporal complexity of earthquake rupture

tsunami modeling to validate slip models of the 2007 mw8 0 pisco earthquake central peru following the 2007 august 15th mw 8 0 pisco earthquake in central peru sladenet al j geophys res 115 b02405 2010 have derived several slip models of this event they inverted teleseismic data together with geodetic insar measurements to look for the co seismic slip distribution on the fault plane considering those data sets separately or jointly but how close to the real slip distribution are those inverted slip models to answer this crucial question the authors generated some tsunami records based on their slip models and compared them to dart buoys tsunami records and available runup data such an approach requires a robust and accurate tsunami model non linear dispersive accurate bathymetry and topography etc otherwise the differences between the data and the model may be attributed to the slip models themselves though they arise from an incomplete tsunami simulation the accuracy of a numerical tsunami simulation strongly depends among others on two important constraints i a fine computational grid and thus the bathymetry and topography data sets used which is not always available unfortunately and ii a realistic tsunami propagation model including dispersion here we extend sladen s work using newly available data namely a tide gauge record at callao lima harbor and the chilean dart buoy record while considering a complete set of runup data along with a more realistic tsunami numerical that accounts for dispersion and also considering a fine resolution computational grid which is essential through these accurate numerical simulations we infer that the insar based model is in better agreement with the tsunami data studying the case of the pisco earthquake indicating that geodetic data seems essential to recover the final co seismic slip distribution on the rupture plane slip models based on teleseismic data are unable to describe the observed tsunami suggesting that a significant amount of co seismic slip may have been aseismic finally we compute the runup distribution along the central part of the peruvian coast to better understand the wave amplification attenuation processes of the tsunami generated by the pisco earthquake

approach to ore forming conditions in light of ore fluid inclusions abundant information of ore fluid inclusions or melting inclusions has been collected from many famous metallic deposits in china on the basis of the authors studies in combination with related data from home and abroad the ore fluids are classified into four types namely mafic ultramafic magma granitic magma volatile component thermal water thermal water and normal temperature water viscosity saturability immiscibility solubility and some other physicochemical parameters of ore fluids seem to be important constraint factors for the formation of ore deposits this paper makes an approach to genetic mechanism of some typical metallic deposits in china based on the researches into temperature pressure salinity and chemical composition of ore fluid inclusions from these deposits

seismology energy radiation from the sumatra earthquake we determined the duration of high frequency energy radiation from indonesia s great sumatra andaman earthquake 26 december 2004 to be about 500 seconds this duration can be translated into a rupture length of about 1 200 km which is more than twice as long as that inferred from body wave analyses performed soon after the event our analysis was able rapidly to define the extent of rupture thereby aiding the assessment of seismic hazard in the immediate future

the 2004 december 26 indian ocean tsunami impact on sri lanka cascade modelling from ocean to city scales summary the 2004 december 26 indian ocean tsunami severely hit sri lanka although it was not in the direct path of the initial tsunami waves the western coast was struck by diffracted waves that caused much damage the numerical model geowave is used to compute tsunami generation propagation and inundation from the earthquake source to the sri lankan coast a nested grid system is constructed to increase the resolution until galle bay on the southwestern coast where a 20 m grid is used the six nested topobathymetric grids are interpolated from etopo2 and high resolution data at sea as onshore simulation results are compared with tsunami height data from national oceanic and atmospheric administration noaa us and geological survey mines bureau gsmb sri lanka when the grid resolution increases the discrepancy between the model and the data remains on average good whereas its spread increases we then conclude that the order of magnitude of the tsunami height is consistent from the 180 m resolution grid but the spatial imprecision is too high to locally predict reliable water heights nevertheless the comparison between computed time series of sea surface elevation at the colombo tide station and tide gauge data shows a very good agreement as both amplitude and arrival time of the first wave are well reproduced when focusing onshore the modelled inundation limit is compared with the limit measured in the field with its a priori setup computed inundation spreads much farther behind the field limit we then integrate more accurate nearshore conditions into the model non linear shallow water equations are chosen instead of fully non linear boussinesq equations the bottom friction on land is increased to a much higher value than at sea the buildings cover and the low tide conditions are taken into account in the dem the resulting high resolution simulation agrees better with field data even if discrepancies are still locally observed in places of dem imprecision and in a river valley this simulation however demonstrates that taking into account nearshore and onshore features may significantly improve tsunami impact assessment

defining the source region of the indian ocean tsunami from gps altimeters tide gauges and tsunami models abstract to understand the role of the co seismic moment magnitude mw 9 1 9 3 sumatra andaman earthquake rupture mechanism on the severity of the indian ocean tsunami we used permanent global positioning system gps data and carried out an analysis of co seismic displacement and tsunami models tsunami modelling validated against independent jason 1 altimetry data and tsunami arrival time data as determined from tide gauges was used to analyse the results of five co seismic slip inversions using gps seismicity and or uplift data in this way we determined the most likely slip distribution characterized by slip maxima of 20 m in the south and 20 m in the north we used both the distribution and temporal evolution of the co seismic slip as derived from the gps data we show that the 9 min propagation time of the rupture led to constructive interference of waves radiating first from the south and minutes later from the north strengthening the tsunami in southern india sri lanka and thailand we conclude that the incorporation of permanent real time gps stations would represent a valuable component of future tsunami warning systems

rupture process of the 2004 sumatra andaman earthquake from tsunami waveform inversion the aim of this work is to infer the slip distribution and rupture velocity along the rupture zone of the 26 december 2004 sumatra andaman earthquake from available tide gage records of the tsunami we selected waveforms from 14 stations distributed along the coast of the indian ocean then we subdivided the fault plane into 16 subfaults both along strike and downdip following the geometry and mech anism proposed by banerjee et al 2005 and computed the corresponding green s functions by numerical solution of the shallow water equations through a finite difference method the slip distribution and rupture velocity were determined simul taneously by means of a simulated annealing technique we compared the recorded and synthetic waveforms in the time domain using a cost function that is a trade off between the l1 and l2 norms preliminary tests on a synthetic dataset together with a posteriori statistical analysis of the model ensemble enabled us to assess the ef fectiveness of the method and to quantify the model uncertainty the main finding is that the best source model features a nonuniform distribution of coseismic slip with high slip values concentrated into three main patches the first is located in the southern part of the fault off the coast of the aceh province the second between 6 5 n and 11 n and the third at depth between 11 n and 14 n furthermore we estimated that the rupture propagated at an average speed of 2 0 km sec

possible atmospheric origin of the 7 may 2007 western black sea shelf tsunami event 1 the paper examines the possibility that tsunami event recorded in the western black sea on 7 may 2007 was triggered by a traveling atmospheric disturbance as meteotsunamis are favored by specific synoptic conditions we inspected available ground and sounding observations european centre for medium range weather forecasts reanalysis fields and satellite based products and compared them to the documented mediterranean meteotsunamis we found an atmospheric disturbance traveling toward 30 nne with amplitude of 2 3 hpa and propagation speed of about 16 m s passing through few tens of kilometers wide pathway over the region affected by the tsunami this disturbance occurred in the lower troposphere but it was capped by instable convective cell that preserved gravity disturbance s coherence over a region at least 150 km long an ocean modeling study showed that such a disturbance is capable of generating large tsunami waves and strong currents over the shallow regions following the observations over the region where maximum sea level oscillations have been documented therefore this event has a potential to be classified as a meteotsunami the first of such kind in the black sea

nature and evolution of hydrothermal fluids in the formation of the tuwu porphyry copper deposit in the eastern tianshan mountains nw china abstract the tuwu porphyry copper deposit is located in the eastern tianshan mountains xinjiang china lentiform like ore bodies are hosted in the early carboniferous qi eshan group and cu mineralization shows a close association with tonalite porphyry porphyry and country rocks have undergone extensive potassic chlorite sericite phyllic and propylitic alteration the mineralized veins in the tuwu deposit can be divided into earlier quartz biotite magnetite chalcopyrite veins stage i quartz chalcopyrite bornite pyrite veins stage ii and quartz molybdenite chalcopyrite pyrite calcite veins stage iii and later calcite quartz veins stage iv the stage ii and iii are the main cu mineralization stages at the tuwu deposit three types of fluid inclusions have been distinguished liquid rich l type vapor rich v type and halite bearing s type respectively laser raman spectra identified magnetite hematite chalcopyrite and pyrite at s type inclusions the quartz veins in stage i and ii contain all inclusion types l type and v type inclusions are recognized in stage iii quartz minerals but only l type inclusions are present in stage iv quartz minerals fluid inclusions in quartz of stage i ii iii and iv are characterized by homogenization temperature vary of 275 492 c 232 477 c 199 287 c and 133 227 c with corresponding nacl equiv salinities of 2 2 58 7 wt nacl equiv 1 4 58 3 wt nacl equiv 1 1 6 0 wt nacl equiv and 1 1 4 2 wt nacl equiv respectively initial ore forming fluids of the tuwu deposit belong to relatively oxidized h2o nacl system with moderate high temperature and salinity sulfur isotope data from chalcopyrite and pyrite suggest a magmatic source two types of chlorite type 1 and type 2 are recognized based on the relationship with metal sulfides electron microprobe analysis shows that chlorites are plotted in ripidolite and pycnochlorite decreasing fe fe mg ratios of chlorites indicate that the meteoric water was involved in the magmatic water combined with the positive correlation with aliv implying that the chlorite formed in a relatively reduced and acidic environment the hydrothermal fluids in type 1 chlorite bring large quantities of reduced metallic minerals compared to the barren fluids in type 2 chlorite the formation temperatures of chlorite are roughly coincident with the results that obtained from fluid inclusion studies which show a decrease trend changes in temperature redox ph and fluid rock interaction likely play an important role in the transportation and precipitation of metal sulfides of the tuwu deposit

seismology speed and size of the sumatra earthquake we now have a clearer picture of the seismic features of last year s gigantic event our seismological results reveal that indonesia s devastating sumatra andaman earthquake on 26 december 2004 was 2 5 times larger than initial reports suggested second only to the 1960 chilean earthquake in recorded magnitude they indicate that it slowly released its energy by slip along a 1 200 km fault generating a long rupture that contributed to the subsequent tsunami now that the entire rupture zone has slipped the strain accumulated from the subduction of the indian plate beneath the burma microplate has been released and there is no immediate danger of a similar tsunami being generated on this part of the plate boundary although large earthquakes on segments to the south still present a threat

the tsunami signature on a submerged promontory the case study of the atacames promontory ecuador shelf promontories exhibit very specific bathymetric features with regards to tsunamis because of their submerged cape morphology a potential tsunami generated seawards of the promontory will exhibit a specific mode of propagation and coastal impact to identify this peculiar tsunami signature the atacames promontory ecuador was chosen as a case study another example is the shelf of the nile delta egypt the area is tectonically very active hosts earthquakes among the most powerful recorded as well as areas of slope instabilities that have triggered significant submarine landslides in the past several cubic kilometres of volume both types of events are likely to be tsunamigenic to examine the tsunami behaviour at the coastal area of the promontory and at its vicinity we have considered two examples of tsunamigenic landslides of which scars were identified near the base of the continental slope we also took into consideration two earthquake scenarios that are likely to represent most classes of earthquakes possibly occurring in this area depending on their locations and subsequent tsunami directivity that is a sensitivity test investigation we took two distinct earthquake scenarios which are based on the 1942 and 1958 events that stroke the area then we computed their derived tsunamis and analysed their coastal impact we found that significant tsunamis can be generated by either landslides or earthquakes however the maxima of wave amplitude occur offshore but still above the underwater promontory the concave type shape of the bathymetric field often yields a refraction focusing area that is located on the shelf promontory and not at the coast area of the promontory the wave propagates first through the focusing area before striking the considered coast this area may be considered as a sheltered zone besides in the vicinity of the promontory not exactly concerned by the study the city of esmeraldas is relatively sheltered due to the presence of the underwater canyon at its termination and due to diverging waves

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

dispersive and nonhydrostatic pressure effects at the front of surge undular bores and shocks generated by dam break flows or tsunamis are examined considering nonhydrostatic pressure and dispersive effects in one and two horizontal dimensional space the fully nonlinear boussinesq type equations based on a weakly nonhydrostatic pressure assumption are chosen as the governing equations the equation set is solved by a fourth order accurate finite volume method with an approximate riemann solver several typical benchmark problems such as dam break flows and tsunami wave fission are tested in one and two horizontal dimensional space the computed results by the boussinesq type model are at least as accurate as the results by the hydrostatic shallow water equations this is particularly evident near the steep front of the wave where frequency dispersion can play an important role the magnitude of this nonhydrostatic pressure and dispersive effect near the front is quantified and the engineering implications of neglecting these physics as would be done through the use of a hydrostatic model are discussed

numerical modeling of the great 2004 indian ocean tsunami focus on the mascarene islands on 26 december 2004 the m w 9 2 sumatra earthquake triggered the greatest tsunami ever observed in recent times the unprecedented quality and variety of observations on modern instruments provide opportunities to refine modeling techniques as well as our perception of tsunami hazard in oceanic regions where historical events are not as frequent as in the pacific ocean we present a numerical modeling of the 2004 tsunami on the mascarene islands with refined computations on la reunion island where postevent survey observations and one tide gauge record are available we use two different source models models a and b to account for the observations and we also test an additional source model model c to study the effect of a tsunami originating in the 1833 epicentral area southern sumatra a wave trapped on the edge of la reunion may explain the greatest water heights reached in the western coastline of the island the observed tide gauge data are reasonably well fit models a and b the run up data can also be explained with our models late disturbances observed in la pointe des galets may be explained by a late tsunami reflection from madagascar or by harbor resonances finally we also show that model c 1833 like strikes la reunion more heavily than models a and b

coupled c s fe geochemistry in a rapidly accumulating marine sedimentary system diagenetic and depositional implications in the present study we have investigated the c s fe systematics in a sediment core md161 13 from the krishna godavari k g basin bay of bengal the core covers the late holocene period with high overall sedimentation rate of 573 cm kyr 1 pore fluid chemical analyses indicate that the depth of the present sulfate methane transition zone smtz is at 6 mbsf the ta ca mg so42 ratios suggest that both organoclastic degradation and anaerobic oxidation of methane aom drive sulfate reduction at the study site the positive correlation between total organic carbon content toc and chromium reducible sulfur crs content indicates marked influence of organoclastic sulfate reduction on sulfidization coupled occurrence of 34s enriched iron sulfide pyrite with 12c enriched authigenic carbonate zones is the possible records of paleo sulfate methane transition zones where aom driven focused sulfate reduction was likely fueled by sustained high methane flux from underlying gas rich zone aluminum normalized poorly reactive iron fepr al and la yb ratios suggest increasing contribution from deccan basalts relative to that of archean proterozoic granitic complex in sediment flux of krishna godavari basin during the last 4 kyr

rupture process of the 2004 sumatra andaman earthquake the 26 december 2004 sumatra andaman earthquake initiated slowly with small slip and a slow rupture speed for the first 40 to 60 seconds then the rupture expanded at a speed of about 2 5 kilometers per second toward the north northwest extending 1200 to 1300 kilometers along the andaman trough peak displacements reached 15 meters along a 600 kilometer segment of the plate boundary offshore of northwestern sumatra and the southern nicobar islands slip was less in the northern 400 to 500 kilometers of the aftershock zone and at least some slip in that region may have occurred on a time scale beyond the seismic band

impact of a lisbon type tsunami on the u k coastline and the implications for tsunami propagation over broad continental shelves 1 we investigate the propagation of tsunamis toward the european shelf break using six different initial conditions based on the 1755 lisbon earthquake in order to assess the hazard to this region only one of our source models an assumed earthquake magnitude of 8 7 mw with a zonal fault orientation resulted in significant wave heights at the u k coastline because of wave spreading only a fraction of the tsunami energy from such an event reaches the northwest european shelf which itself provides a further buffer through reflection and frictional dissipation however we found significant local reamplification due to wave interactions and resonance on the continental shelf the maximum elevations obtained were comparable to severe winter storm conditions but with extreme local variability in the tsunami amplitude our results suggest that the impact of any repeat of this event would be very sensitive to the precise location and orientation of the source deformation as well as by complex topographic interactions on the shelf the uncertainties arising from the combination of source orientation and bathymetric interaction suggest that any assessment of risk for places where tsunamis are likely should consider a large ensemble of initial conditions

pacific basin tsunami hazards associated with mass flows in the aleutian arc of alaska abstract we analyze mass flow tsunami generation for selected areas within the aleutian arc of alaska using results from numerical simulation of hypothetical but plausible mass flow sources such as submarine landslides and volcanic debris avalanches the aleutian arc consists of a chain of volcanic mountains volcanic islands and submarine canyons surrounded by a low relief continental shelf above about 1000 2000 m water depth parts of the arc are fragmented into a series of fault bounded blocks tens to hundreds of kilometers in length and separated from one another by distinctive fault controlled canyons that are roughly normal to the arc axis the canyons are natural regions for the accumulation and conveyance of sediment derived from glacial and volcanic processes the volcanic islands in the region include a number of historically active volcanoes and some possess geological evidence for large scale sector collapse into the sea large scale mass flow deposits have not been mapped on the seafloor south of the aleutian islands in part because most of the area has never been examined at the resolution required to identify such features and in part because of the complex nature of erosional and depositional processes extensive submarine landslide deposits and debris flows are known on the north side of the arc and are common in similar settings elsewhere and thus they likely exist on the trench slope south of the aleutian islands because the aleutian arc is surrounded by deep open ocean mass flows of unconsolidated debris that originate either as submarine landslides or as volcanic debris avalanches entering the sea may be potential tsunami sources to test this hypothesis we present a series of numerical simulations of submarine mass flow initiated tsunamis from eight different source areas we consider four submarine mass flows originating in submarine canyons and four flows that evolve from submarine landslides on the trench slope the flows have lengths that range from 40 to 80 km maximum thicknesses of 400 800 m and maximum widths of 10 40 km we also evaluate tsunami generation by volcanic debris avalanches associated with flank collapse at four locations makushin cleveland seguam and yunaska sw volcanoes which represent large to moderate sized events in this region we calculate tsunami sources using the numerical model topics and simulate wave propagation across the pacific using a spherical boussinesq model which is a modified version of the public domain code funwave our numerical simulations indicate that geologically plausible mass flows originating in the north pacific near the aleutian islands can indeed generate large local tsunamis as well as large transoceanic tsunamis these waves may be several meters in elevation at distal locations such as japan hawaii and along the north and south american coastlines where they would constitute significant hazards

the tsunami of 26 december 2004 numerical modeling and energy considerations a numerical model for the global tsunamis computation constructed by kowalik et al 2005 is applied to the tsunami of 26 december 2004 in the world ocean from 80 s to 69 n with spatial resolution of one minute because the computational domain includes close to 200 million grid points a parallel version of the code was developed and run on a cray x1 supercomputer an energy flux function is used to investigate energy transfer from the tsunami source to the atlantic and pacific oceans although the first energy input into the pacific ocean was the primary direct wave reflections from the sri lankan and eastern shores of maldives were a larger source the tsunami traveled from indonesia around new zealand and into the pacific ocean by various routes the direct path through the deep ocean to north america carried miniscule energy while the stronger signal traveled a considerably longer distance via south pacific ridges as these bathymetric features amplified the energy flux vectors travel times for these amplified energy fluxes are much longer than the arrival of the first wave these large fluxes are organized in the wave like form when propagating between australia and antarctica the sources for the larger fluxes are multiple reflections from the seychelles maldives and a slower direct signal from the bay of bengal the energy flux into the atlantic ocean shows a different pattern since the energy is pumped into this domain through the directional properties of the source function the energy flow into the pacific ocean is approximately 75 of the total flow to the atlantic ocean in many locations along the pacific and atlantic coasts the first arriving signal or forerunner has lower amplitude than the main signal which often is much delayed understanding this temporal distribution is important for an application to tsunami warning and prediction

earth s free oscillations excited by the 26 december 2004 sumatra andaman earthquake at periods greater than 1000 seconds earth s seismic free oscillations have anomalously large amplitude when referenced to the harvard centroid moment tensor fault mechanism which is estimated from 300 to 500 second surface waves by using more realistic rupture models on a steeper fault derived from seismic body and surface waves we approximated free oscillation amplitudes with a seismic moment 6 5 10 22 newton meters that corresponds to a moment magnitude of 9 15 with a rupture duration of 600 seconds the fault rupture models represent seismic observations adequately but underpredict geodetic displacements that argue for slow fault motion beneath the nicobar and andaman islands

southern ocean origin for the resumption of atlantic thermohaline circulation during deglaciation during the two most recent deglaciations the southern hemisphere warmed before greenland at the same time the northern atlantic ocean was exposed to meltwater discharge which is generally assumed to reduce the formation of north atlantic deep water yet during deglaciation the atlantic thermohaline circulation became more vigorous in the transition from a weak glacial to a strong interglacial mode here we use a three dimensional ocean circulation model to investigate the impact of southern ocean warming and the associated sea ice retreat on the atlantic thermohaline circulation we find that a gradual warming in the southern ocean during deglaciation induces an abrupt resumption of the interglacial mode of the thermohaline circulation triggered by increased mass transport into the atlantic ocean via the warm indian ocean and cold pacific ocean water route this effect prevails over the influence of meltwater discharge which would oppose a strengthening of the thermohaline circulation a southern ocean trigger for the transition into an interglacial mode of circulation provides a consistent picture of southern and northern hemispheric climate change at times of deglaciation in agreement with the available proxy records

late quaternary precessional cycles of terrigenous sediment input off the norte chico chile 27 5 s and palaeoclimatic implications abstract the palaeoclimatic conditions during the last glacial maximum lgm of southern south america and especially latitudinal shifts of the southern westerly wind belt are still discussed controversially longer palaeoclimatic records covering the late quaternary are rare a particularly sensitive area to late quaternary climatic changes is the norte chico northern chile because of its extreme climatic gradients small shifts of the present climatic zonation could cause significant variations of the terrestrial sedimentary environment which would be recorded in marine terrigenous sediments to unveil the history of shifting climatic zones in northern chile we present a sedimentological study of a marine sediment core geob 3375 1 from the continental slope off the norte chico 27 5 s sedimentological investigations include bulk and silt grain size determinations by sieving atterberg separation and detailed sedigraph analyses additionally clay mineralogical parameters were obtained by x ray diffraction methods the 14c dated core covering the time span from approximately 10 000 to 120 000 cal yr b p consists of hemipelagic sediments terrigenous sedimentological parameters reveal a strong cyclicity which is interpreted in terms of variations of sediment provenance modifications of the terrestrial weathering regimes and modes of sediment input to the ocean these interpretations imply cyclic variations between comparatively arid climates and more humid conditions with seasonal precipitation for northern chile 27 5 s through the late quaternary the cyclicity of the terrigenous sediment parameters is strongly dominated by precessional cycles for the palaeoclimatic signal this means that more humid conditions coincide with maxima of the precession index as e g during the lgm higher seasonal precipitation for this part of chile is most likely derived from frontal winter rain of the southern westerlies thus the data presented here favour not only an equatorward shift of this atmospheric circulation system during the lgm but also precession controlled latitudinal movements throughout the late quaternary precessional forcing of latitudinal movements of the westerly atmospheric circulation system may be conceivable through teleconnections to the northern hemisphere monsoonal system in the atlantic ocean region

late quaternary rapid climate change in northern chile analyses of terrigenous sediments from the chilean continental slope off the southern border of the atacama desert 27 5 s focusing on illite crystallinity and the fe al ratio of the sediments reveal a high frequency variability of the position of the southern westerlies which is very similar to the coeval short term climatic events known from greenland ice cores and from north atlantic sediments besides showing dominantly precession driven variability in precipitation over the andes these analyses also reveal rapid changes in weathering intensity along the chilean coastal range during the last 80 000 years these rapid changes occur at much shorter timescales than the 19 100 kyr orbital forcing of the milankovitch cycles

tsunami source of the 2004 sumatra andaman earthquake inferred from tide gauge and satellite data tsunami source of the 2004 sumatra andaman earthquake was esti mated from a joint inversion of tsunami waveforms recorded on tide gauges and sea surface heights captured by satellite altimetry measurements the earthquake the largest in the past 40 years caused devastating tsunami damage to countries around the indian ocean but the tsunami source in particular its northern end was not well resolved although aftershocks and crustal deformation extended from off north western sumatra island through the nicobar islands to the andaman islands some seismic wave analyses indicated a shorter source length several hundred kilometers we used tsunami waveforms recorded at 12 tide gauge stations around the source and the sea surface heights measured by three satellites jason1 topex poseidon and envisat we numerically computed tsunami propagation using realistic bathym etry more than 66 000 depth points were digitized from nautical charts and combined with the etopo2 data inversion of satellite data indicates that the tsunami source extended to the andaman islands with a total length of 1 400 km but such a model produces much larger tsunami waveforms than observed at indian tide gauge stations inversion of tide gauge records and the joint inversion indicate that the tsunami source was about 900 km long the largest slip about 13 to 25 m was located off sumatra island and the second largest slip up to 7 m near the nicobar islands the slip distribution is similar for different rupture velocities and rise times with a slow velocity of 1 km sec and a rise time of 3 min yielding the largest variance reduction

fluid evolution of the tongkuangyu porphyry copper deposit in the zhongtiaoshan region evidence from fluid inclusions abstract the tongkuangyu porphyry copper deposit is located in the zhongtiaoshan region southern margin of the north china craton more than 2 8 million tons of cu average cu grade 0 68 is hosted in the paleoproterozoic quartz monzonite porphyry 2122 10 ma the ore forming processes of the tongkuangyu porphyry cu deposit are divided into three mineralization stages namely the early main and late mineralization stages the majority of cu ores were formed in the main stage which is characterized by veinlets and disseminated chalcopyrite and minor molybdenite pyrite magnetite and hematite quartz is the major gangue mineral which occurs as veinlets and associates with metallic minerals through systematic petrographic observation the ore bearing quartz veins a type quartz and the quartz hosted in chalcopyrite b type quartz were studied in detail to investigate the fluid evolution of the tongkuangyu porphyry cu deposit four types of fluid inclusions were recognized in the a type quartz which include 1 pure vapor or vapor rich v type inclusions 2 co 2 h 2 o c type inclusions 3 liquid rich l type inclusions and 4 daughter mineral bearing s type inclusions s type inclusions in the main stage a type quartz contain mainly halite and minor sylvite calcite hematite chalcopyrite and anhydrite with homogenization temperatures of 233 450 c v type inclusions coexisting with the s type inclusions homogenize to vapor phase at 282 375 c suggesting that the ore forming fluids may have experienced boiling in the main mineralization stage the late stage s type inclusions have homogenization temperatures of 186 245 c and contain largely halite with minor sylvite fluid inclusions in the b type quartz intergrown with chalcopyrite are closely associated with the ore forming processes the main stage b type quartz contains predominantly s type inclusions with homogenization temperatures of 250 412 c and minor v type inclusions on the other hand the late stage b type quartz contains abundant s type inclusions with homogenization temperatures of 195 230 c and less l type inclusions our results show that the s type inclusions in both the a and b type quartz of the same ore stage have very similar homogenization temperatures therefore fluid boiling may have promoted the cu enrichment in the high salinity fluids and the brine phase is the main metal transport medium in the tongkuangyu porphyry cu deposit the common occurrence of hematite and anhydrite daughter minerals in the s type inclusions further suggests that ferrous ion oxidization may have caused sulfate reduction this process may have played an important role during the cu precipitation event the progressive cooling of fluids and the incorporation of meteoric water in the late mineralization stage possibly resulted in the small scale vein type mineralization

modelling of tsunami generated by the giant late bronze age eruption of thera south aegean sea greece summary tsunami generated by the late bronze age lba eruption of thera were simulated using synthetic tide records produced for selected nearshore 20 m depths sites of northern crete the cyclades islands sw turkey and sicily inundation distances inland were also calculated along northern crete modelling was performed by incorporating fully non linear boussinesq wave theory with two tsunamigenic mechanisms the first involved the entry of pyroclastic flows into the sea assuming a thick 55 m 30 km3 flow entering the sea along the south coast of thera in three different directions all directed towards northern crete then a thin pyroclastic flow 1 m 1 2 km3 entering the sea along the north coast of thera directed towards the cyclades islands flows were modelled as a solid block that slowly decelerates along a horizontal surface the second mechanism assumed caldera collapse of 19 km3 and 34 km3 modelled as a dynamic landslide producing rapid vertical displacements calculated nearshore wave amplitudes varied from a few metres to 28 m along northern crete from pyroclastic flows and up to 19 m from caldera collapse 34 km3 volume inundation distances on crete were 250 450 m waves produced by pyroclastic flows were highly focused however as a function of sea entry direction smaller volume pyroclastic flows produced nearshore wave amplitudes up to 4 m in the cyclades islands north of thera wave amplitudes in the cyclades from smaller volume caldera collapse 19 km3 were up to 24 m whereas in sw turkey were as low as 2 1 and 0 8 m didim and fethye where lba tsunami deposits have been found wave amplitudes for the larger volume caldera collapse 34 km3 were generally 2 5 3 times larger than those generated by the smaller volume collapse 19 km3 these results provide estimates for understanding possible consequences of tsunami impact in lba coastal zones thus providing criteria at archaeological sites for detecting inundation damage as well as for contemporary hazard assessment they also provide additional criteria for deciphering homogenite layers in the abyssal stratigraphy of the ionian and eastern mediterranean seas

antarctic timing of surface water changes off chile and patagonian ice sheet response marine sediments from the chilean continental margin are used to infer millennial scale changes in southeast pacific surface ocean water properties and patagonian ice sheet extent since the last glacial period our data show a clear antarctic timing of sea surface temperature changes which appear systematically linked to meridional displacements in sea ice westerly winds and the circumpolar current system proxy data for ice sheet changes show a similar pattern as oceanographic variations offshore but reveal a variable glacier response time of up to 1000 years which may explain some of the current discrepancies among terrestrial records in southern south america

did a submarine landslide contribute to the 2011 tohoku tsunami many studies have modeled the tohoku tsunami of march 11 2011 as being due entirely to slip on an earthquake fault but the following discrepancies suggest that further research is warranted 1 published models of tsunami propagation and coastal impact underpredict the observed runup heights of up to 40 m measured along the coast of the sanriku district in the northeast part of honshu island 2 published models cannot reproduce the timing and high frequency content of tsunami waves recorded at three nearshore buoys off sanriku nor the timing and dispersion properties of the waveforms at offshore dart buoy 21418 3 the rupture centroids obtained by tsunami inversions are biased about 60 km nne of that obtained by the global cmt project based on an analysis of seismic and geodetic data together with recorded tsunami waveforms we propose that while the primary source of the tsunami was the vertical displacement of the seafloor due to the earthquake an additional tsunami source is also required we infer the location of the proposed additional source based on an analysis of the travel times of higher frequency tsunami waves observed at nearshore buoys we further propose that the most likely additional tsunami source was a submarine mass failure smf i e a submarine landslide a comparison of pre and post tsunami bathymetric surveys reveals tens of meters of vertical seafloor movement at the proposed smf location and a slope stability analysis confirms that the horizontal acceleration from the earthquake was sufficient to trigger an smf forward modeling of the tsunami generated by a combination of the earthquake and the smf reproduces the recorded on near and offshore tsunami observations well particularly the high frequency component of the tsunami waves off sanriku which were not well simulated by previous models the conclusion that a significant part of the 2011 tohoku tsunami was generated by an smf source has important implications for estimates of tsunami hazard in the tohoku region as well as in other tectonically similar regions

dispersive modeling of the 2009 samoa tsunami 1 in this study we investigate the dispersive effects in the 2009 samoa tsunami through numerical simulations the wave propagation is first simulated with a weakly nonlinear and dispersive boussinesq model and a non dispersive shallow water equations model comparison of the numerical results between these models indicates that tsunami propagation is significantly affected by the frequency dispersion east of tonga trench neglecting dispersive effects results in larger wave heights and speeds the strong frequency dispersion is primarily attributed to the dramatic variation of water surface elevations generated by the earthquake doublet and enhanced by the uneven bathymetry in tonga trench tsunami propagation is also simulated with most method of splitting tsunamis which is based on the shallow water equations but uses numerical dispersion to mimic physical frequency dispersion at operational resolutions a good agreement is observed between most and the boussinesq model as well as the field measurements in the leading wave in the shorter trailing waves agreement becomes poorer due to the mismatch between numerical and physical dispersions

observational analysis on the run up height and inundation along the andhra coast during december 26 2004 indian ocean tsunami abstract the 26 december 2004 earthquake with magnitude of 9 3 triggered one of the most destructive tsunamis in the indian ocean and caused widespread inundation and extensive damage in terms of life and property along the coasts of several asian countries in india the andaman and nicobar group of islands the coastal states of tamil nadu andhra pradesh and kerala were severely affected post tsunami field surveys were conducted along the andhra coast central part of east coast of india to assess the tsunami run up heights and inundation estimation of tsunami run up heights and inundation relative to the mean sea level were made based on the water marks on permanent structures and marks of debris on trees observations revealed that the andhra coast was largely affected by the tsunami and in general the intensity of the tsunami along the andhra coast decreased from south to north maximum run up heights of 4 5 m were observed in the southern parts and minimum run up heights of 2 m were observed in the northern parts of the andhra coast while the distance of inundation varied from 60 to 900 m along the coast the interdependency between the tsunami run up height and inundation with the physical setup of the shoreline has been identified also local features such as dunes vegetation and steepness of beaches played vital role in reducing the impact of tsunami dependency of tsunami parameters on coastal characteristic index cci was attempted for the first time for the indian coast good correlation has been observed between run up heights inundation and cci the width of the continental shelf also played a crucial role in causing damage to the coast

fe speciation and fe al ratio in the sediments of southeastern arabian sea as an indicator of climate change aluminum titanium and iron are the major lithogeneous contributors to the marine sediment and their abundance varies strikingly with the intensity of monsoonal precipitation al and ti concentration in a sediment core sk 129 gc 05 from southeastern arabian sea exhibit very strong positive correlation r 0 92 n 140 suggesting their lithogenous association whereas ti and fe does not correlate so strongly r 0 44 this suggests that part of fe is present as structurally unsupported and is evident by two fold increased fe al ratio 0 87 average compared to upper continental crust 0 44 the presence of structurally unsupported fe is confirmed by the sequential leaching of fe which is associated with different fractions such as exchangeable 0 98 carbonate 1 98 fe mn oxide 30 8 organic carbon 4 7 and biogenic opal 11 4 which together constitutes nearly 50 of the bulk fe content there is a good correlation between time series fe al and differential solar insolation suggesting warmer and humid climatic condition resulting intense weathering of hinterland rocks associated with increased monsoonal precipitation probably decoupled soluble fe and its transportation to southeastern arabian sea

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

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

dynamics and coastal effects of tsunamis generated by asteroids impacting the black sea two dimensional 2d and one dimensional 1d shallow water models are used to evaluate the seashore effects of the tsunami generated by an asteroid impacting the western regions of the black sea about 208 km from the coast the tsunami s speed and the effects on the coastal regions depend on many factors among which the most important is asteroid size the tsunami generated by a 250 m asteroid reaches the nearest land location in 24 min and needs about 2 h to arrive at all black sea coast the run up value is about 7 m high on the turkish and crimean coasts in the western black sea regions the wave height is two or three times smaller the run up values strongly depend on bathymetry and topography peculiarities the run in value in case of the tsunami generated by a 1 000 m asteroid is up to eight times larger than in case of a 250 m impactor depending on location the results reported herein are upper limit values in case of the 250 m asteroid the real wave amplitude may be up to two times smaller the uncertainty factor decreases in case of larger asteroids ways of diminishing the social consequences are briefly discussed

far field tsunami impact in the north atlantic basin from large scale flank collapses of the cumbre vieja volcano la palma in their pioneering work ward and day suggested that a large scale flank collapse of the cumbre vieja volcano cvv on la palma canary islands could trigger a mega tsunami throughout the north atlantic ocean basin causing major coastal impact in the far field while more recent studies indicate that near field waves from such a collapse would be more moderate than originally predicted by ward and day lovholt et al j geophy res 113 c09026 2008 abadie et al j geophy res 117 c05030 2012 these would still be formidable and devastate the canary island while causing major impact in the far field at many locations along the western european african and the us east coasts abadie et al j geophy res 117 c05030 2012 simulated tsunami generation and near field tsunami impact from a few cvv subaerial slide scenarios with volumes ranging from 20 to 450 km 3 the latter representing the most extreme scenario proposed by ward and day they modeled tsunami generation i e the tsunami source using thetis a 3d navier stokes ns multi fluid vof model in which slide material was considered as a nearly inviscid heavy fluid near field tsunami impact was then simulated for each source using funwave tvd a dispersive and fully nonlinear long wave boussinesq model shi et al ocean modell 43 44 36 51 2012 kirby et al ocean modeling 62 39 55 2013 here using funwave tvd for a series of nested grids of increasingly fine resolution we model and analyze far field tsunami impact from two of abadie et al s extreme cvv flank collapse scenarios i that deemed the most credible worst case scenario based on a slope stability analysis with a 80 km 3 volume and ii the most extreme scenario similar to ward and day s with a 450 km 3 volume simulations are performed using a one way coupling scheme in between two given levels of nested grids based on the simulation results the overall tsunami impact is first assessed in terms of maximum surface elevation computed along the western european and african and us east coasts usec strong wave elevation decay is predicted over the wide usec shelf which is shown to be essentially due to bottom friction effects we then show more detailed results for the usec which is the object of high resolution tsunami inundation mapping under the auspices of the us national tsunami hazard mitigation program in this context we compare the maximum surface elevation predicted along the coastline for each cvv scenario and show that besides the initial directionality of the sources coastal impact is mostly controlled by focusing defocusing effects resulting from the shelf bathymetric features a simplified ray tracing analysis confirms this controlling effect of the wide usec shelf for incident long waves finally we perform high resolution 10 m inundation mapping for the most extreme cvv scenario and show results at one of the most vulnerable and exposed communities in the mid atlantic us states in and around ocean city maryland such maps are being generated for all exposed areas of the usec to be used in tsunami hazard assessment and mitigation work

kinematics and source zone properties of the 2004 sumatra andaman earthquake and tsunami nonlinear joint inversion of tide gauge satellite altimetry and gps data 1 we re analyzed the source of the 26 december 2004 sumatra andaman earthquake and tsunami through a nonlinear joint inversion of an inhomogeneous data set made up of tide gauges satellite altimetry and far field gps recordings the purpose is twofold 1 the retrieval of the main kinematics rupture parameters slip rake and rupture velocity and 2 the inference of the rigidity of the source zone we independently estimate the slip from tsunami data and the seismic moment from geodetic data to derive the rigidity our results confirm that the source of the 2004 sumatra andaman earthquake has a complex geometry constituted by three main slip patches with slip peaking at 30 m in the southern part of the source the rake direction rotates counterclockwise at the northern part of the source according to the direction of convergence along the trench the rupture velocity is higher in the deeper than in the shallower part of the source consistent with the expected increase of rigidity with depth it is also lower in the northern part consistent with known variations of the incoming plate properties and shear velocity our model features a rigidity 20 30 gpa that is lower than the preliminary reference earth model prem average for the seismogenic volume the source rigidity is one of the factors controlling the tsunami genesis for a given seismic moment the lower the rigidity the higher the induced seafloor displacement the general consistence between our source model and previous studies supports the effectiveness of our approach to the joint inversion of geodetic and tsunami data for the rigidity estimation

effects of shear band propagation on early waves generated by initial breakoff of tsunamigenic landslides the landslide mechanism based on the phenomenon of the dynamic shear band propagation suggests that landslide run out begins with a non zero initial velocity the initial uplift of the passive failure block during the landslide breakoff is similar to the reverse fault and therefore can generate an early tsunami wave that will be one of the first waves to start propagating and could be potentially detected by the deep ocean warning systems this paper attempts to quantify this phenomenon using the coupled eulerian lagrangian cel approach within abaqus and modeling both soil and water as eulerian materials this approach allows for capturing the entire process of failure initiation propagation and breakoff taking into account large landslide deformations soil plasticity and interaction of the sliding layer with the seawater the study shows that the highest breakoff velocities are achieved for the shortest lengths of the initial weak zones initiating the shear band propagation it also shows that both interaction of the sliding layer with water and appearance of the large plastic failure zones during the shear band propagation cause slower uplift velocities and accelerations for the computed example of a typical mid size landslide in normally consolidated clays with the initial weak zone length of several hundred meters and the final landslide length of about 1 km the breakoff velocities can reach up to 4 m s within 15 s leading to an early wave of 0 5 1 5 m height caused purely by this breakoff such waves can be easily detected by existing deep ocean assessment and reporting of tsunamis dart systems potentially allowing for some early tsunami warning

reconstructions of the coastal impact of the 2004 indian ocean tsunami in the khao lak area thailand 1 khao lak sw thailand was severely affected by the tsunami on 26 december 2004 here we present reconstructions of its coastal impact in this area these are based on 1 eyewitness reports alone and 2 eyewitness reports supported by videos and photos of the tsunami and the damage it caused field measurements and satellite imagery on the basis of eyewitness reports we estimated that the sea began retreating at 1000 local time lt and based also on photos that the tsunami arrived at 1026 1029 lt on the basis of videos of the tsunami we estimated an offshore wave direction of 083 3 and on the basis of the paths by which eyewitnesses were carried we estimated an onshore direction of 088 6 on the basis of videos we calculated that the velocity of the wavefront on its final approach was 33 4 km h we obtained tsunami heights of 7 3 0 8 m relative to ground level on the basis of eyewitness reports and 8 0 0 6 m relative to mean sea level on the basis of field and photographic data on the basis of eyewitness reports and photos we concluded that khao lak experienced at least two main waves with a period 40 min from eyewitness reports and satellite imagery we measured maximum inundation 0 5 km in the southern part of the area which is confined by a steeply sloping hinterland and 1 5 km in the more gently sloping northern part comparison between these reconstructions supports the reliability of eyewitness reports as a source of quantitative data and comparison with the numerical simulation by ioualalen et al 2007 supports the validity of the simulation

tsunami impact computed from offshore modeling and coastal amplification laws insights from the 2004 indian ocean tsunami the 2004 indian ocean tsunami gave the opportunity to gather unprecedented tsunami observation databases for various coastlines we present here an analysis of such databases gathered for 3 coastlines among the most impacted in 2004 in the intermediate and far field thailand myanmar se india sri lanka and se madagascar non linear shallow water tsunami modeling performed on a single 4 coarse bathymetric grid is compared to these observations in order to check to which extent a simple approach based on the usual energy conservation laws either green s or synolakis laws can explain the data the idea is to fit tsunami data with numerical modeling carried out without any refined coastal bathymetry topography to this end several parameters are discussed namely the bathymetric depth to which model results must be extrapolated using the green s law or the mean bathymetric slope to consider near the studied coast when using the synolakis law using extrapolation depths from 1 to 10 m generally allows a good fit however a 0 1 m is required for some others especially in the far field madagascar possibly due to enhanced numerical dispersion such a method also allows describing the tsunami impact variability along a given coastline then using a series of scenarios we propose a preliminary statistical assessment of tsunami impact for a given earthquake magnitude along the indonesian subduction conversely the sources mostly contributing to a specific hazard can also be mapped onto the sources providing a first order definition of which sources are threatening the 3 studied coastlines

is there a best source model of the sumatra 2004 earthquake for simulating the consecutive tsunami summary many studies have attempted to invert the fault source of the sumatra 2004 event whereas they mostly consider the same fault geometry they lead to a wide range of potential slip distributions using tsunami modelling with geowave a model based on fully non linear boussinesq equations we investigate the influence of five distinct source models of various origins and the influence of rupture kinematics on the generated tsunami the simulation results are considered both at ocean scale and at country scale we then compare the results along the jason 1 track to the corresponding sea surface height anomaly ssha profile and examine the patterns of maximum sea surface elevation around the bay of bengal and on the eastern and southern coastlines of sri lanka in most cases the synthetic ssha profiles are not very consistent with the observed one although they all display a prevailing first wave the divergence in maximum sea surface elevation appears in particular along the sri lankan coast where three of the models lead to a clearly underestimated tsunami impact the best models derive from purely seismic and geodetic studies that did not consider any tsunami modelling thus suggesting that the methods to invert a fault model from tsunami data still need some adjustment especially concerning the handling of coastal data in addition it is important to consider the rupture kinematics along such a long fault as the generated tsunami is more significant than when considering an instantaneous rupture in the case of the sumatra 2004 event the tsunami impact on sri lanka is notably underestimated if modelled without the rupture kinematics we conclude that for tsunami modelling a complex description of the fault source model is not absolutely necessary but some significant parameters such as rupture kinematics should be taken into account

on the use of satellite altimetry to infer the earthquake rupture characteristics application to the 2004 sumatra event summary standard data and methods such as the inversion of seismic and gps data have been used extensively to infer the details of the 2004 december 26 earthquake the unprecedented large size of this event gave the opportunity to modern altimeters to provide the first clear records of a tsunami in deep ocean therefore allowing us to study the rupture history from an independent perspective we invert the jason 1 and topex poseidon altimetry records considering the new constraints available on the geometry of the fault plane and taking them into account in a 3 d rupture model the data are corrected for the non negligible effect of satellite motion during measurements our results show that the rupture propagated over the 1500 km of subduction zone initially identified by the aftershock distribution with a magnitude of mw 9 1 our solution compares well with the latitudinal distribution of slip inferred from other data sets with a maximum of energy release north of sumatra and two other slip patches near the nicobar and andaman islands based on waveform comparison we assert that the shallow portion of the megathrust offshore banda aceh had slip amplitudes of more than 20 m also we find that significant amounts of slip about 10 m concentrated below the andaman islands and did not propagate on the shallow portion of the interface although synthetic tests tend to show less resolution in the northern part of the rupture this solution is compatible with the near field data gps coral heads and imagery and would allow one to explain the apparent paradox between the large local displacements and the moderate tsunami observed locally finally we demonstrate the rapidly dominating effect of propagation and slip distribution over the rupture velocity and how it precludes the direct estimate of this latter parameter

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