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

tsunami run up associated with co seismic thrust slip produced by the 2011 mw 9 0 off pacific coast of tohoku earthquake japan abstract the 2011 m w 9 0 off pacific coast of tohoku japan earthquake generated a violent tsunami and unexpected high tsunami wave that caused great substantial damage and 18 940 fatalities along the east northeast coast of honshu island of japan analyses of high resolution remote sensing imagery data acquired before and after the earthquake combined with the results of field investigations reveal that i run up height of the tsunami i e the inland limit of tsunami was spatially variable ranging from w 9 0 earthquake and showed a gradual decrease away from this region combined with the ground motion direction revealed by gps and seismic data the distribution of run up height is consistent with that of ground displacement calculated from gps observations and that of co seismic thrusting slip on the source fault plane along the plate boundary calculated from the seismic inversion the results of numerical simulation of tsunami propagation show that i the distributions of tsunami height along the northeast honshu coastline are constrained mainly by thrusting slip on the source fault plane and ii the height of tsunami wave in special areas was strongly affected by the sawtooth geometry of the coastline

the lefkada barrier and beachrock system nw greece controls on coastal evolution and the significance of extreme wave events abstract the lefkada preveza coastal zone nw greece is characterised by an active barrier system and related extensive beachrock sequences besides the gradual coastal processes of longshore drift and spit evolution the presence of active tectonics and the occurrence of tsunamis have been documented in previous studies and are part of the coastal geomorphological system in this paper we present the results of detailed multi proxy sedimentological and geomorphological investigations carried out along the northern part of the barrier system and in back beach positions our findings suggest that extreme wave events contributed to coastal and environmental changes and involved temporary breakdown of the barrier system sedimentary findings suggest that one generation of event deposits may be related to the 365 ad crete earthquake and associated tsunami according to our results the lefkada coastal system formed by the interaction of both long term gradual and sudden impulsive littoral geomorphodynamics extreme wave events are assumed to have played a significant role in the evolution of the present coastline acting as recurrent impulsive disturbances of the coastal system subsequently the onset of long term gradual coastal processes such as longshore drift re established a state of natural coastal balance by re arranging the coastal sediments

tsunamis in the aeolian islands southern italy a review the aeolian islands located in the south tyrrhenian sea to the west of calabria and to the north of sicily constitute the aeolian volcanic arc characterized by a relevant volcanic activity with an established tsunamigenic potential according to the documentary sources that are available for the aeolian tsunamis and that cover unfortunately only about the last 100 years stromboli is responsible for the majority of the events some cases are also known to have occurred at the islands of salina and vulcano in terms of intensities the most destructive events are those originated by the stromboli volcano reported to have produced severe destruction to boats and houses and to have even caused injuries and fatalities in this work we focus on the historical events and discard the paleotsunami occurrences that were probably associated with the ascertained flank collapses of the volcanic cones we also neglect the recent destructive tsunamis of 30 december 2002 which were caused by a series of mass failures at the sciara del fuoco since observations and analyses are of such an amount that deserve to be illustrated in devoted papers the bulk of the present research consisted in collecting all the available data on the historical cases the first in order of time is the july 1916 stromboli tsunami with the purpose of casting more light on their generation mechanism and on their effects and consequently of contributing to the studies on assessment of tsunami hazard and risk in the aeolian islands and in the southern tyrrhenian sea

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

reexamination of the a d 869 jogan earthquake size from tsunami deposit distribution simulated flow depth and velocity the rupture parameters and magnitude of the a d 869 jogan earthquake a predecessor of the 2011 tohoku earthquake were previously estimated by matching tsunami deposit distributions with simulated inundation areas the tsunami inundation associated with the 2011 tohoku earthquake however extended farther inland than the sandy tsunami deposits numerical simulation of the 2011 tsunami indicated that flow depths and velocities were approximately 1 m and 0 6 m s respectively at the most inland sand deposit sites on the ishinomaki and sendai plains while these values depend on the assumed bottom roughness we used these values to compare tsunami deposits and inundation simulation of the 869 jogan earthquake from both uniform slip and 2011 type variable slip fault models the results showed that the rupture length of the 869 jogan earthquake was at least 200 km and its minimum moment magnitude was 8 6

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

bonaire s boulder fields revisited evidence for holocene tsunami impact on the leeward antilles abstract supralittoral boulders and blocks are prominent sedimentary features along rocky shorelines worldwide in most cases their deposition is attributed to high energy wave events tsunamis severe storms even though tsunami waves are expected to have higher transport capacities compared to storm waves megaclasts of up to 100 t were observed to have been moved laterally by the latter waveform the deduction of certain extreme wave events tsunamis severe storms from the boulder record thus remains a major challenge in palaeo event research the debate on their differentiation is ongoing at the eastern coast of bonaire leeward antilles in the southern caribbean numerous limestone blocks and boulders up to c 130 t are distributed on top of a 3 6 m a s l above mean sea level palaeo reef platform disagreement exists among a number of authors concerning the transport processes involved in the formation of the boulder fields in this paper state of the art modelling approaches of coastal boulder entrainment and transport were applied in order to provide new and more reliable data to support challenge the working hypothesis of tsunami deposition to improve the reliability of the boulder transport model more realistic input parameters were provided by new dgps measurements of the boulder dimensions and the calculation of bulk densities by taking into account the heterogeneity of the reef rock boulders existing hydrodynamic equations were modified to allow for the irregular shape and real dimensions of the boulders the results indicate that i boulder weight and dimension and thus ii calculated wave energy and wave heights were overestimated in most of the previous studies where calculations of boulder volume were based on multiplication of the main axes the results of this study and wave heights observed during recent severe tropical cyclones seem to rule out storm generated waves for the dislocation of the largest blocks however the majority of coarse clast deposits may have been generated by periodic hurricane swells the results underline the significance of more realistic field data in modelling boulder transports by waves

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

tsunami sculpturing of the pebble beach wave cut platform crescent city area california abstract bedrock sculpturing of semilithified st george formation sandy mudstone exposed on a wave cut platform has produced a variety of erosional forms that include surface scratches made by beach debris ripple like ridges that reflect differential erosion of bedrock potholes and scallop shaped pockets and grooves which may be straight or sinuous straight grooves form by preferential incision of regional joints sinuous grooves are not fracture controlled are oriented parallel to wave run up orthogonal to the coast and exist as closely spaced subparallel nonconnecting internally drained grooves that are best developed on higher platform ramparts and benches sinuous grooves have a mean length of 258 cm mean maximum width of 14 cm and mean width length ratio of 0 08 they are not as deeply incised as straight grooves do not serve as conduits for low tide runoff during winter months and typically terminate by shallowing and narrowing in both seaward and landward directions sinuous appeara

darts and cork in cascadia basin high resolution observations of the 2004 sumatra tsunami in the northeast pacific 1 we report unique deep sea recordings of the sumatra tsunami of december 2004 by high resolution dart deep ocean assessment and reporting of tsunami and cork circulation obviation retrofit kit bottom pressure sensors deployed at depths of 1500 3500 m in cascadia basin in the northeast pacific the simultaneous records from these sites establish the first ever regional scale tsunami detection array for the open ocean enabling us to resolve both seafloor and crustal tsunami signals and to determine fundamental properties of the waves following their 22 000 km journey from the source region waves reaching the basin had mean amplitudes of 5 mm with energy spread over a broad frequency band from 0 4 to 7 cph peak tsunami energy was in the 0 8 to 2 cph 75 to 30 min band leading waves from the event arrived 34 35 h after the earthquake roughly 7 h later than expected suggesting that the tsunami mainly propagated by the most economic minimum energy loss path along mid ocean ridge wave guides rather than taking the direct and fastest path across the ocean motions within the peak energy band comprise roughly 50 coherent progressive waves propagating from the south at longwave phase speeds of 150 ms 1 and 50 random waves scattered from the coast and bottom irregularities tsunami amplitudes in the borehole were one third those on the seafloor the extensive ringing and anomalously slow 3 5 day e folding decay time of the tsunami wave energy indicates long duration energy flux radiating from the indian ocean via the southern pacific ocean

extremely high energy wave deposits inside the great barrier reef australia determining the cause tsunami or tropical cyclone abstract a hydrodynamic approach is used to determine whether tsunami or cyclone generated waves were responsible for the deposition of fields of well imbricated rock boulders up to 290 tonnes along the coast of cairns inside the great barrier reef australia calculations of the overturning moments show that only tsunami are capable of moving such large boulders in this environment it is hypothesised that large tsunami 11 m have been able to penetrate the great barrier reef through wide 5 10 km 50 70 m deep passages between individual reefs three such passages each approximately 35 km apart and oriented in the same direction exist in the cairns region it is possible that these passages have funnelled and amplified palaeotsunamis the preferential location of eroded coral boulders up to 3 m in length on reef flats alongside these passages and their absence on other reefs throughout the region provide further evidence that extremely high energy waves have been able to penetrate the great barrier reef into the inner channel adjacent to the mainland carbon 14 ages of the coral boulders on these reef flats matches closely the ages of coral fragments pinned below the very large rock boulders along the coast these ages suggest that the cairns region has experienced large tsunami twice over the last millennium

enso prediction one year in advance using western north pacific sea surface temperatures 1 we present evidence that the de trended boreal winter sea surface temperature anomalies ssta in the western north pacific wnp are a skillful predictor for the development of the el nino southern oscillation enso by the following winter the wnp shares some similarities with the meridional mode mm located in the subtropical central and eastern north pacific both are linked to off equatorial ssta and low level wind anomalies and both appear to be strongly related to wintertime variability in the north pacific oscillation npo however in contrast with the mm the wnp is associated with an opposite signed ssta dipole located off southeastern asia and in the western tropical pacific which is accompanied by equatorial winds that may influence the level of oceanic kelvin wave activity that precedes enso events

generation mechanism of tsunamis from the 1883 krakatau eruption the 1883 eruption of krakatau generated a destructive tsunami which claimed about 34 000 lives we compute the generation and propagation of tsunamis from three models previously proposed they are 1 large scale caldera collapse of the northern part of krakatau island 2 emplacement of pyroclastic flow deposits 3 submarine explosion we numerically solve the non linear shallow water equations on actual bathymetry all three models displace the same volume 11 5 km 3 of water in different ways we compare the results of our computation with the observed tsunami waveforms at batavia and tsunami wave heights along the coasts of java and sumatra the comparison shows that the submarine explosion model of 1 to 5 min duration best explains the generation of the largest tsunami

multi proxy evidence for trans pacific tsunamis in the hawai ian islands abstract the origin of two sand layers buried in polol wetland on the northeast coast of the island of hawai i was investigated using a multi proxy approach including radiometric dating sedimentology geochemistry micropalaeontology palynology and historical records based on 210 pb 137 cs and pollen data the lower sand unit extending 250 to 350 m inland is attributed to the 1946 aleutian tsunami while the upper sand unit was laid down by the 1957 aleutian tsunami chronological information does not appear to support any link between these deposits and historical storm events furthermore sedimentological geochemical diatom and pollen results suggest deposition of marine and near beach sediments under high energy conditions typically associated with tsunami inundation this work presents the first conclusive sedimentary evidence for distantly generated tsunamis on the hawai ian islands opening the way for more comprehensive historical and palaeotsunami studies indeed a brief review of archaeological data suggests that the hawai ian coast may have experienced similar large magnitude events in the past from both local and distant sources

challenges of anticipating the 2011 tohoku earthquake and tsunami using coastal geology 1 can the magnitude of a giant earthquake be estimated from paleoseismological data alone attempts to estimate the size of the jogan earthquake of ad 869 whose tsunami affected much of the same coast as the 2011 tohoku tsunami offers an excellent opportunity to address this question which is fundamental to assessing earthquake and tsunami hazards at subduction zones between 2004 and 2010 examining stratigraphy at 399 locations beneath paddy fields along 180 km of coast mainly south of sendai we learned that a tsunami deposit associated with the ad 869 jogan earthquake had run inland at least 1 5 km across multiple coastal lowlands and that one of the lowlands had subsided during the jogan earthquake and an earlier earthquake as well radiocarbon ages just below above sand deposits left by the pre jogan tsunamis suggested recurrence intervals in the range of 500 to 800 years modeling inundation and subsidence we estimated size of the jogan earthquake as moment magnitude 8 4 or larger and a fault rupture area 200 km long we did not consider a longer rupture like the one in 2011 because coastal landform and absence of a volcanic ash layer make any jogan layer difficult to identify along the sanriku coast still sendai tsunami geology might have reduced casualties by improving evacuation maps and informing public awareness campaigns

on the effect of the water body geometry on landslide tsunamis physical insight from laboratory tests and 2d to 3d wave parameter transformation preliminary landslide tsunami hazard assessment is commonly based on empirical equations derived from wave channel 2d or wave basin 3d experiments the far field wave in 2d can easily be an order of magnitude larger than in 3d the present study systematically investigates the effect of the water body geometry on the wave characteristics in the near and far field subaerial landslide tsunami tests were conducted relying upon both a 2d and a 3d physical model undertaken with identical boundary conditions the test parameters included two water depths three rigid slides as well as various slide release positions empirical equations for 3d offshore and laterally onshore wave properties are presented and compared with previous work a direct comparison of the wave features reveals that the waves decay in 2d 3d onshore and 3d offshore with x 0 30 r 0 67 and r 1 0 where x 2d and r 3d describe the distance from the impact zone in 2d four wave types are observed whereas only the two least non linear types were observed in 3d this finding is further analysed with wavelet spectra for a large slide froude number f relative slide thickness s and relative slide mass m the 3d wave heights in the slide impact zone can be as large as in 2d however for small f s and m the 3d waves are considerably smaller both in the near and far field a novel method is presented and validated to transform data from 2d studies to 3d this method may have favourable implications on preliminary landslide tsunami hazard assessment

the 2011 tohoku oki earthquake tsunami similarities and differences to the 869 jogan tsunami on the sendai plain a post tsunami field survey following the 2011 tohoku oki earthquake tsunami was carried out to asses inundated area in sendai plain northeast japan the type of inundation was classified into two categories major and minor according to the amount of accumulated debris garbage and sediment major and minor inundations were identified up to 4 and 5 km from the coastline respectively many artificial geomorphological features such as roadway embankments and canals were believed to have affected the run up process of the tsunami the inundation area of the 2011 tsunami on the sendai plain is compared with that of the 869 jogan tsunami which was reconstructed using numerical modeling based on available historical and geological records the inundation area of the 2011 tohoku oki tsunami is comparable to that of the 869 jogan tsunami although a direct comparison is difficult due to differences in geomorphological contexts between the paleo period and the present

the combined role of bay and shelf modes in tsunami amplification along the coast 1 the role of free modes of oscillation of coastal areas in tsunami amplification at the coast is investigated here a finite element numerical model for modal analysis was applied and the numerically calculated natural frequencies were compared to those resulting from the spectra of measured sea level time series two case studies have been selected that of poverty bay new zealand and that of kuluk bay adak island alaska usa the natural modes of the sea areas that extend in front of these locations are shown to play an important role in tsunami amplification at both the considered bays in fact the enhancement of wave height is found to be related to both the small scale resonance controlled by the coastal shape and the large scale one governed by the continental shelf bathymetry in particular the model application to poverty bay reveals that some of the continental shelf modes are more energetic and occur at frequencies higher than the bay fundamental one these modes are identified as both cross shelf modes and trapped edge waves on the other hand the application to kuluk bay shows that geographical entrapment can be relevant for chain islands making the bay and the continental shelf modes almost coincident

the tsunami phenomenon abstract with human activity increasingly concentrating on coasts tsunamis from japanese tsu harbour nami wave are a major natural hazard to today s society stimulated by disastrous tsunami impacts in recent years for instance in south east asia 2004 or in japan 2011 tsunami science has significantly flourished which has brought great advances in hazard assessment and mitigation plans based on tsunami research of the last decades this paper provides a thorough treatise on the tsunami phenomenon from a geoscientific point of view starting with the wave features tsunamis are introduced as long shallow water waves or wave trains crossing entire oceans without major energy loss at the coast tsunamis typically show wave shoaling funnelling and resonance effects as well as a significant run up and backflow tsunami waves are caused by a sudden displacement of the water column due to a number of various trigger mechanisms such are earthquakes as the main trigger submarine and subaerial mass wastings volcanic activity atmospheric disturbances meteotsunamis and cosmic impacts as is demonstrated by giving corresponding examples from the past tsunamis are known to have a significant sedimentary and geomorphological off and onshore response so called tsunamites form allochthonous high energy deposits that are left at the coast during tsunami landfall tsunami deposits show typical sedimentary features as basal erosional unconformities fining upward and landward a high content of marine fossils rip up clasts from underlying units and mud caps all reflecting the hydrodynamic processes during inundation the on and offshore behaviour of tsunamis and related sedimentary processes can be simulated using hydro and morphodynamic numerical models the paper provides an overview of the basic tsunami modelling techniques including discretisation guidelines for appropriate temporal and spatial resolution as well as the nesting method furthermore the boussinesq approximation a simplification of the three dimensional navier stokes equations is presented as a basic theory behind numerical tsunami models which adequately reflects the non linear dispersive wave behaviour of tsunamis the fully non linear boussinesq equations allow the simulation of tsunamis e g in the form of n waves based on the various subtopics presented recommendations for future multidisciplinary tsunami research are made it is especially discussed how the combination of sedimentary and geomorphological tsunami field traces and numerical modelling techniques can contribute to derive locally relevant tsunami sources and to improve the assessment of tsunami hazards considering the individual pre history and physiogeographical setting of a specific region

deep sea observations and modeling of the 2004 sumatra tsunami in drake passage 1 the 2004 sumatra tsunami was clearly recorded by two uk bottom pressure gauges dpn and dps deployed in drake passage between south america and antarctica these open ocean records were examined to estimate characteristics of the tsunami waves and to compare the results of numerical simulations with the observations maximum wave heights measured at these gauges were 4 9 cm at dpn and 7 4 cm at dps the travel times from the source area were 19 h 46 min and 19 h 39 min respectively consistent with the times obtained from the nearby coastal tide gauges the numerical model described well the frequency content amplitudes and general structure of the observed waves with only small time shifts probably related to wave dispersion effects the shifts were 15 min for dpn and 10 min for dps with the modeled waves leading the observations in each case further inspection of the simulated and observed records revealed that the identified tsunami waves are related to the second main train of waves propagating by the energy conserving route along the mid ocean ridges while the first train of waves travelling by the fastest route across the ocean remained unrecognizable in the observed dps and dpn records and undetectable in the records of coastal tide gauges because of their insignificant amplitudes compared to the background variability

heavy minerals in the 2011 tohoku oki tsunami deposits insights into sediment sources and hydrodynamics abstract the 2011 tohoku oki tsunami left sand and mud deposits more than 4 km inland on the coastal plain of sendai japan the tsunami deposits pre tsunami soils and beach sediments were analysed for grain size and heavy mineral content and assemblages to test the applicability of heavy mineral analyses in the identification of tsunami deposits and interpretation of associated sedimentation processes heavy minerals comprised on average 35 of the tsunami deposit in the 0 125 0 25 mm grain size fraction the most common were orthopyroxenes clinopyroxenes amphiboles limonites and opaque minerals heavy mineral concentrations and assemblages were similar in the tsunami deposits beach and pre tsunami soils and sediments and thus tsunami deposits could not simply be identified based on their heavy minerals sediment provenance analysis revealed that tsunami deposits left within 1 5 km of the shoreline were mostly eroded from the beach dune and local soils while deposits farther inland 1 5 km were mostly derived from local soil erosion no evidence was found for a significant contribution of offshore sediments detailed analyses revealed that the lowermost portion of tsunami deposits was mostly of local origin while the sediment source of the upper portion was variable a comparison with a previous study of heavy minerals in 2004 iot deposits confirms that heavy minerals in tsunami deposits are mostly source dependent and may represent a useful supplementary tool in studies of tsunami deposits however the interpretation must always be placed in the local geological context and corroborated with other tsunami proxies

inflow and outflow facies from the 1993 tsunami in southwest hokkaido abstract we describe in detail the sedimentary facies provenance and grain size distributions of the 1993 tsunami deposits in the lower reaches of usubetsu river only two lithofacies were recognized a gravel lobe facies glf and a sand sheet facies ssf the gravel lobe facies was deposited rapidly by a hydraulic jump in contrast the sand sheet facies which contains both current ripples and dunes was deposited by a traction current under subcritical flow conditions we identified four stratigraphic units unit 1 unit 2 unit 3 and unit 4 in ascending order we interpreted units 1 and 2 as having been deposited by the inflow and outflow events of the first run up and units 3 and 4 by the inflow and outflow events of the second run up respectively units 3 and 4 were more widely distributed and coarser grained than units 1 and 2 because the second run up was larger than the first run up furthermore unit 4 was more widely distributed than unit 3 because the outflow eroded the inflow deposits grain size distributions of the inflow and outflow deposits were clearly different unit 4 deposits had a peak at 2 5 phi p 1 population in contrast unit 3 deposits had a bimodal distribution with peaks at 0 5 1 5 phi p 2 population and at 2 5 phi p 1 population a comparison of the tsunami deposits with other sedimentary deposits near the study area showed that the tsunami deposits were mainly derived from the seabed at depths below 5 5 m in the offshore area where the marine sands are about 2 2 5 phi in size and thus are the source of the p 1 population the p 2 population is derived from coarse 0 5 2 phi fluvial materials eroded during the tsunami run up according to our calculations benthic foraminiferal tests were entrained from the comparatively deep seabed at depths up to 100 m during the tsunami run up and included in the tsunami deposits

the 8 5 magnitude ad365 earthquake in crete coastal uplift topography changes archaeological and historical signature abstract an up to 9 m uplift of western crete a cluster of coastal uplifts in the east mediterranean radiocarbon dated approximately 1500 bp as well as historical and archaeological data are evidence for major although poorly documented seismic destruction on a nearly mediterranean scale in the 4th to 5th c ad including the destruction of the nile delta in egypt by a tsunami in ad365 these data represent parts of a puzzle for historians archaeologists geologists and seismologists detailed analysis of geological historical and archaeological data including precise numismatic evidence permits recognition of a major earthquake in crete responsible for coastal uplift at ad365 elastic dislocation analysis of coastal uplift data reveals that this earthquake was associated with a reverse fault offshore of southwestern crete that its minimum magnitude was 8 5 and that this model is consistent with the available seismological and large scale tectonic data despite its magnitude this earthquake cannot have produced the necessary short period high energy waves which are necessary to explain the seismic damage which occurred circa ad365 in a very broad region from sicily to cyprus and libya hence the ad365 earthquake sequence included at least two other major events with epicentres close to cyprus and sicily although significant changes in the coastal morphology widespread destruction and a high human death toll occurred the ad365 crete earthquake was not responsible for any major cultural change it occurred during the transition from the roman to the christian period characterized by vast luxurious villas and modest dwellings on crete respectively

a technique for quantifying groundwater pumping and land subsidence using a nonlinear stochastic poroelastic model subsidence in yunlin county taiwan is serious and continuous the taiwan high speed rail thsr route crosses the subsidence area and might be affected by differential settlements it is important to evaluate the pumping quantity for water resource management and to predict the subsidence for land resource management to mitigate the subsidence problem in taiwan this study combines first order second moment fosm stochastic poroelastic theory with nonlinear parameters to develop a fosm nonlinear stochastic poroelastic model and applies it to quantify groundwater pumping and future subsidence with uncertainty the additional loading and discharge are evaluated by fitting the subsidence historical data to the numerical model the results show that the proposed model well describes the subsidence behavior and quantifies groundwater pumping however the numerical results are larger than the monitoring data at various depths which might be due to the different compaction situations in individual formations of the aquifer system the predicted subsidence at the yuanchang monitoring well is the largest 0 32 0 52 m in 2020 with consideration of the climate change effects achieved by adding an additional discharge of 31 7 the large uncertainty is caused by the large variation of hydraulic conductivity caused by the heterogeneity of the aquifer system which could be improved by doing more experiments or using a conditioned model the information provided in this study is useful for the safety of thsr and for land and groundwater resource management in yunlin county taiwan

preservation potential of sedimentary event layers preservation potential of sedimentary event layers e g ash layers or tempestites is a function of net sedimentation rate and biogenous mixing rate previous studies that have used an inverse peclet number to scale the problem in terms of advection or diffusion are in error due to the improper inclusion of the surface mixed layer thickness as the sole length scale herein focus is on time scales if the transit time i e time required to advect the signal through the biologically active zone is less than the dissipation time i e time required to destroy the signal then some fraction of the original signal is preserved a simple quantitative model based on the diffusion analogy of sediment mixing estimates the actual percentage of preserved signal under various combinations of sedimentation rate mixing rate and event layer thickness

source of the 2007 ist meteotsunami adriatic sea 1 siroka bay on the island of ist in the northern adriatic was struck by a severe inundation around 1530 utc on 22 august 2007 the maximum wave height reached 4 m and substantial material damage was induced this paper investigates the generating force of the inundation data analysis indicates that the inundation was provoked through a double resonance mechanism with initiation by a pronounced atmospheric disturbance that generated open ocean waves through the proudman resonance the waves were then further amplified inside the affected bay the air pressure disturbance which propagated at a speed of about 21 24 m s 1 over the northern adriatic shelf was investigated through both data analysis and atmospheric numerical modeling apparently the air pressure disturbance was a surface manifestation of a ducted gravity wave which propagated through the atmosphere from the apennines to the eastern adriatic coast over the northern adriatic according to the model simulation the wave was trapped in a stable layer adjacent to the ground which was capped by a dynamically unstable layer with wind speeds of about 22 m s 1 this made the unstable layer also a critical layer for gravity waves propagating with the same speed and allowed for their ducting in the layer below

introduction to tsunami science ten years after the 2004 indian ocean tsunami volume i twenty papers on the study of tsunamis and respective tsunamigenic earthquakes are included in volume ii of the pageoph topical issue tsunami science ten years after the 2004 indian ocean tsunami the papers presented in this second of two special volumes of pure and applied geophysics reflect the state of tsunami science during this time including five papers devoted to new findings specifically in the indian ocean two papers compile results from global observations and eight papers cover pacific ocean studies focusing mainly on the 2011 tohoku earthquake and tsunami remaining papers in this volume describe studies in the atlantic ocean and mediterranean sea and tsunami source studies overall the volume not only addresses the pivotal 2004 indian ocean and 2011 tohoku tsunamis but also examines the tsunami hazard posed to other critical coasts in the world

an experimental study of the interaction of two successive solitary waves in the swash a strongly interacting case and a weakly interacting case abstract the interaction of successive solitary waves in the swash zone have been studied using large scale experiments with a simple bathymetry of a constant depth region where the water depth was 1 72 m and a plane beach whose slope was 1 12 two wave cases were considered where two successive solitary waves of the same height were generated one after the other so that the wave crests were separated by the effective wavelength associated with a single solitary wave in the weakly interacting case the swash period associated with a single solitary wave is smaller than the time period separating the successive wave crests which leads to similar run ups for the first and second wave whereas in the strongly interacting case the swash period associated with a single solitary wave is larger than the time period separating the successive wave crests which leads to a significant reduction in the run up of the second wave the degree to which there is an interaction between the swash uprush of the second wave and the downrush of the first wave is found to be related to the solitary wave slope parameter which predicts breaker type of the first wave previous data from literature are found to support this claim measurements of bed shear stress bed pressure and the free surface displacement at a location near the stillwater shoreline are used to describe how the dynamics of the boundary layer differ when the downrush of the first wave meets the incoming second wave in both cases

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

discrimination of boulders deposited by tsunamis and storm waves at ishigaki island japan abstract the ryukyu islands japan where numerous boulders are deposited on the reef and on land might be ideal research fields of boulders deposited by tsunami and storm waves because many typhoons and several tsunamis attacked the same area during its history this study investigates the size position and the long axis orientation of 626 boulders at ibaruma and shiraho reefs at ishigaki island japan to elucidate the sedimentary differences of boulders deposited by tsunamis and storm waves in one area two distinct groups of boulders were found at these reefs boulders on the reef crest group 1 and along the shoreline group 2 boulders in group 1 porites sp of moat origin the group 2 boulders were remarkably heavier 14 c age based on results of this study we infer that tsunami boulders in these islands so called tsunami ishi can be discriminated from boulders of storm wave origin based on their sedimentary differences this sedimentological approach is expected to be applicable to other boulder fields throughout the world our results further suggest that the spatial and grain size distribution of tsunami boulders are very useful to elucidate local flow characteristics of the tsunami for example the group 2 tsunami boulders were deposited below the high tide line irrespective of size some were split into several pieces they were probably deposited below the high tide line by the remarkable reduction of the current velocity of the tsunami because of the local topography the reduction of the current velocity must have been drastic to have made the boulders hit the ground with sufficient force to split them

waves coastal boulder deposits and the importance of the pre transport setting the pre transport environment of a coastal boulder along with its shape size and density determines the height of wave required for it to be transported different forces act on sub aerial boulders as opposed to submerged boulders when struck by a wave boulders derived from joint bounded blocks on shore platforms predominantly experience lift force and require a wave of greater height to be transported than boulders in other environments no one equation is applicable to determine the height of palaeo waves responsible for depositing a field or ridge of imbricated coastal boulders a range of equations and their derivation is presented here which can be applied to the respective pre transport environment of a boulder such an approach is necessary when attempting to reconstruct the frequency and magnitude of past coastal wave hazards and for differentiating between tsunami and storm wave deposited boulder fields

propagation and amplification of tsunamis at coastal boundaries when tsunamis hit a coastal area they often cause substantial damage and loss of life at locations otherwise well protected from normal even severe wind generated waves an example of such a catastrophe took place on 12 december 1992 when an earthquake of magnitude ms 7 5 occurred in the eastern region of flores island indonesia1 2 one of the areas hardest hit by the resulting tsunamis was babi a small coastal island two villages on the island were completely destroyed even though both were located in sheltered areas where wave conditions are normally calm here we describe the results of numerical and laboratory experiments that show how unlike wind generated waves tsunamis are capable of penetrating into sheltered coastal areas without significantly losing their energy for the case of babi island the original tsunami wave was split into two with one wave propagating around each side of the island the two waves met in the sheltered region and the subsequent amplification of wave amplitude resulted in the destructive flow onto the beach

including debris cover effects in a distributed model of glacier ablation 1 distributed glacier melt models generally assume that the glacier surface consists of bare exposed ice and snow in reality many glaciers are wholly or partially covered in layers of debris that tend to suppress ablation rates in this paper an existing physically based point model for the ablation of debris covered ice is incorporated in a distributed melt model and applied to haut glacier d arolla switzerland which has three large patches of debris cover on its surface the model is based on a 10 m resolution digital elevation model dem of the area each glacier pixel in the dem is defined as either bare or debris covered ice and may be covered in snow that must be melted off before ice ablation is assumed to occur each debris covered pixel is assigned a debris thickness value using probability distributions based on over 1000 manual thickness measurements locally observed meteorological data are used to run energy balance calculations in every pixel using an approach suitable for snow bare ice or debris covered ice as appropriate the use of the debris model significantly reduces the total ablation in the debris covered areas however the precise reduction is sensitive to the temperature extrapolation used in the model distribution because air near the debris surface tends to be slightly warmer than over bare ice overall results suggest that the debris patches which cover 10 of the glacierized area reduce total runoff from the glacierized part of the basin by up to 7

sediment instability and slumping in the southern aegean sea and the case history of the 1956 tsunami the aegean and ionian seas in greece and adjacent regions constitute the most tsunamigenic areas in europe the most recent large tsunami was a 20 m high wave that generated on 9 july 1956 in the amorgos basin south aegean sea in association with a ms 7 5 earthquake we first present new evidence for sea floor sediment instability from bathymetric shallow and intermediate penetration seismic profiles and a number of gravity cores second we investigate the generation mechanism of the 1956 large tsunami the determination of the mean repeat time of the minimum seismic ground acceleration required for slump triggering of sediment masses showed that in particular south aegean basins like the argolikos and amorgos ones the mean recurrence of massive sediment slumping ranges between 50 and 100 years in other basins however it is around or more than 500 years in the southern amorgos basin a large scale sediment slump has been identified this was probably triggered by the 1956 mainshock and or its aftershock of ms 7 2 that occurred in the slump source area 13 min after the mainshock the generation of the 1956 tsunami is attributed to the combined action of a reactivated large normal fault to the south of the amorgos island and to the occurrence of the large sediment slump

catastrophic wave erosion on the southeastern coast of australia impact of the lanai tsunamis ca 105 ka sand barriers along the coast of southern new south wales dating from the last interglacial have been almost completely destroyed most probably by a catastrophic tsunami evidence for catastrophic wave erosion can also be traced to heights of at least 15 m above present sea level on coastal abrasion ramps these erosional features lie above the range of effective erosion by contemporary storm waves and cannot be attributed to either eustatic fluctuations or local uplift chronological evidence for the timing of the destruction of the last interglacial barriers suggests that tsunamis generated by the submarine slide off lanai in the hawaiian islands 105 ka traveled across the pacific and eroded this coast

tsunami source of the 2011 tohoku oki earthquake japan inversion analysis based on dispersive tsunami simulations 1 the large tsunami of the 2011 tohoku oki earthquake was clearly recorded by the ocean bottom pressure and gps wave gauges deployed in and around japan we estimated the initial tsunami water height distribution by inversion analysis of the waveforms based on dispersive tsunami simulations the distribution is characterized by a peak height of 8 m located near the trench and the high water 2m region extending landward with a width of 100 km a series of numerical simulations suggests that a relatively steep peak located near the trench is necessary in order to simultaneously reproduce the dispersive wave at a far field station and the near field waveforms furthermore we estimated the coseismic slip distribution at the plate boundary which indicates that large slip 30 m occurred at a depth of 20 km which corresponds to a large slip deficit area in the interseismic period another slip 25 m occurred at the shallower part 10 km during the rupture

source and short distance propagation of the july 9 1956 southern aegean tsunami abstract properties of the tsunamigenic source as well as the attenuation of the tsunami intensities of the large tsunami of july 9 1956 in the southern aegean are investigated this tsunami was generated by a shallow earthquake with a surface wave magnitude of 7 5 which was caused by a normal fault fault plane solution isoseismal lines and bathymetric information indicate that the tsunamigenic source had an elliptical shape with the large axis equal to 110 km and oriented in an ene wsw direction this is also the strike of the normal fault which produced the earthquake and it is probable that the southern block was downthrown linear relations between a the tsunami intensity and the epicentral distance for distances up to 330 km b the observed tsunami height and the epicentral distance and c the tsunami height and intensity have been determined this information concerning the source parameters of tsunamis and the attenuation of the tsunami intensity and tsunami height with distance are of great importance for determining the tsunami hazard in this area

laboratory experiments of tsunami runup on a circular island laboratory experiments of a 7 2 m diameter conical island were conducted to study three dimensional tsunami runup the 62 5 cm tall island had 1 on 4 side slopes and was positioned in the center of a 30 m wide by 25 m long flat bottom basin solitary waves with height to depth ratios ranging from 0 05 to 0 20 and source lengths ranging from 0 30 to 7 14 island diameters were tested in water depths of 32 and 42 cm twenty seven capacitance wave gages were used to measure surface wave elevations at incident and four radial transects on the island slope maximum vertical runup measurements were made at 20 locations around the perimeter of the island using rod and transit a new runup gage was located on the back or lee side of the island to record runup time series

late holocene tsunami traces on the western and southern coastlines of the peloponnesus greece abstract greece in particular the western and southern parts close to the subduction zone of the hellenic trench experiences strong earthquakes and subsequent tsunamis nevertheless field evidence of tsunamis from the late holocene is extremely rare our research along the coastlines of the western and southern peloponnesus resulted in new findings of tsunami impacts in the form of clusters and ridges of large boulders and thick tsunamigenic sand layers encountered in vibracores many boulders contained attached marine organisms which prove that they were transported from the foreshore environment against gravity by extreme wave events the attached organisms which have been dated by 14 c ams suggest that historical tsunami events of great energy occurred around 1300 cal ad a wood fragment found at the base of tsunami deposits in a vibracore from cape punta was dated to 250 cal ad

2004 indian ocean tsunami flow velocity measurements from survivor videos 1 the tsunami of 26th december 2004 severely affected banda aceh along the north tip of sumatra indonesia at a distance of 250 km from the epicenter of the magnitude 9 0 earthquake this tsunami flow velocity analysis focused on two survivor videos recorded within banda aceh more than 3 km from the open ocean the exact locations of the tsunami eyewitness video recordings were revisited by the survey team between february 22 and 25 2005 to record camera calibration ground control points the motion of the camera during the recordings was determined the individual video images were rectified with a direct linear transformation dlt assuming a planar water surface at the level finally a cross correlation based particle image velocimetry piv analysis was applied to the rectified video images to determine instantaneous tsunami flow velocity fields the measured tsunami flow velocities were within the range of 2 to 5 m s

sedimentological and geoarchaeological evidence of multiple tsunamigenic imprint on the bay of palairos pogonia akarnania nw greece abstract this paper presents evidence of multiple tsunami impact on the bay of palairos pogonia nw greece during the holocene based on detailed geo scientific studies altogether 41 vibracores were drilled to detect high energy influence in the stratigraphical record layers of coarse grained allochthonous marine deposits were found intersecting autochthonous fine grained back beach sediments in the palairos coastal plain on top of beach or marly bedrock units at pogonia beach and along the pogonia cliff section high energy deposits are associated with specific sedimentary structures such as fining upward sequences rip up clasts basal erosional contact bi to multimodal grain size distribution lamination and co existence of both well rounded and angular sharply edged components all of them typical of tsunami impact macro and microfaunal analyses revealed tsunami related input of numerous ex situ marine species and mostly angular shell debris into quiescent fresh to brackish water environments by high energy and long distance transport geophysical methods helped to find subsurface structures and to seize the lateral extent of tsunami layers ca fe ratios derived from xrf measurements were used to trace tsunami influence inland most important is the widespread spatial distribution of the tsunamites with a lateral extent between 70 m at the pogonia cliff section 200 m at pogonia beach and 1 km in the central palairos plain and overall tendencies of fining and thinning towards inland highest elevations of tsunamites were found around pogonia village at ca 7 5 m a s l vibracore data give evidence that the overall coastal evolution has been strongly affected locally even controlled by multiple high energy impact a conspicuous geoarchaeological tsunamite up to 1 5 m thick was found at pogonia cliff consisting of mixed marine sand pebbles bio erosively altered stones shell debris foraminifers and terrigenous material abundant ceramic fragments bones building material it is directly associated with the submerged remains of an ancient mole which was destroyed and its building material partly dislocated by the same event dating of tsunamites was accomplished by archaeological age determination of diagnostic sherds and by radiocarbon and luminescence dating techniques strong tsunami events were dated to the beginning of the 6th the mid 5th the 4th 3rd and the late 2nd millennia bc as well as to the 4th 3rd century bc on a regional scale the recurrence interval for large events is ca 500 1000 years at least twice during the late holocene the palairos coastal plain was flooded quasi contemporaneously from both the northern and southern side

island edifice failures and associated tsunami hazards volcanic ocean islands are prone to structural failure of the edifice that result in landslides that can generate destructive tsunamis these island landslides range enormously in size varying from small rock falls to giant sector failures involving tens of cubic kilometers of debris a survey of literature has allowed us to identify twenty three processes that contribute to edifice collapse these have been divided into endogenetic and exogenetic sources of edifice failure endogenetic sources of instability and failure include unstable foundations volcanic intrusions thermal alteration edifice pore pressures unbuttressed structures and buried faults exogenetic sources of instability and failure include collapse of subaerial or submarine deposits endo upwelling karst megaporosity fractures oversteepening overloading sea level change marine erosion weathering including hurricanes glacial response volcanic activity regional uplift or subsidence tectonic seismicity and anthropogenic agents while the endogenetic sources dominate during periods of active volcanism and cone building the exogenetic sources may cause failure at any time tsunamis both small and large are associated with these edifice failures

tsunami as agents of geomorphic change in mid ocean reef islands low lying atoll islands appear highly vulnerable to the effects of climate change and extreme natural events potentially disastrous effects of future sea level rise have been inferred in many studies and the actual impacts of tropical storms on island destruction and formation have been well documented in contrast the role of tsunami in the geomorphic development of atoll islands has not been investigated the sumatran earthquake of 26 december 2004 generated a tsunami that reached the maldives 2500 km away with waves up to 2 5 m high observations on the geomorphic changes resulting from the tsunami are detailed here based on pre and post tsunami profile measurements of island beach and reef topography and gps surveys of the planform shape of islands and beaches of 11 uninhabited islands in south maalhosmadulu atoll maldives erosional and depositional impacts were observed on all islands and these have been quantified in general the changes were of a minor nature with a maximum reduction in island area of 9 and average of 3 75 rather the tsunami accentuated predictable seasonal oscillations in shoreline change including localised erosion reflected in fresh scarps and seepage gullies depositional features in the form of sand sheets and sand lobes emplaced on the vegetated island surfaces provide clear evidence that the tsunami waves washed over parts of all the islands both erosional scarps and overwash deposits were concentrated at the tsunami exposed eastern sides of the islands impacts on leeward shores were primarily accretionary in the form of spit and cuspate foreland extension whereas the nature and magnitude of intra and inter island impacts was variable an east to west decline in aggregate effects was noted detailed consideration of the morphodynamic interaction between the tsunami waves and island morphology show that this cross atoll gradient resulted not just from the reduction in tsunami energy as it passed through the atoll but also from variations in elevation of the encircling island ridge and the quantity and distribution of sediment in the antecedent beach a conceptual model identifying the sequence of changes to individual islands supports the observational data and the pattern of geomorphic changes resulting from the tsunami this model leads to consideration of the longer term impacts of the tsunami on the future stability of islands four scenarios are presented each of which has a different island beach sediment budget and different relaxation time to achieve dynamic equilibrium

the use of boulders for characterising past tsunamis lessons from the 2004 indian ocean and 2009 south pacific tsunamis tsunamis are high energy events capable of transporting extremely heavy loads including boulders we compare boulder deposits created by two modern tsunami events the 2004 indian ocean and the 2009 south pacific tsunamis where the boulder sources were in similar topographic settings and for which we have accurate data on the wave characteristics boulder distribution preferential orientation and numerical simulation of boulder transport are discussed a comparison between the impacts of the south pacific and indian ocean tsunamis shows similar characteristics such as limited landward extent and the absence of landward fining differences between the results from modelling and field data are most probably caused by variables such as coastal plain roughness buildings trees microtopography particle shape and boulder collision during transport that are summarised as coefficients in the mathematical models characterising modern events through coarse sediment deposits provides valuable information to help identify and interpret palaeo tsunami imprints on coastal landscapes

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

the ground based insar monitoring system at stromboli volcano linking changes in displacement rate and intensity of persistent volcanic activity stromboli volcano aeolian archipelago southern italy experienced an increase in its volcanic activity from late december 2012 to march 2013 when it produced several lava overflows major strombolian explosions crater wall collapses pyroclastic density currents and intense spatter activity an analysis of the displacement of the ne portion of the summit crater terrace and the unstable nw flank of the volcano sciara del fuoco depression has been performed with a ground based interferometric synthetic aperture radar gbinsar by dividing the monitored part of the volcano into five sectors three in the summit vents region and two in the sciara del fuoco changes in the displacement rate were observed in sectors 2 and 3 field and thermal surveys revealed the presence of an alignment of fumaroles confirming the existence of an area of structural discontinuity between sectors 2 and 3 high displacement rates in sector 2 are interpreted to indicate the increase in the magmastatic pressure within the shallow plumbing systems related to the rise of the magma level within the conduits while increased displacement rates in sector 3 are connected to the lateral expansion of the shallow plumbing system the increases and decreases in the displacement rate registered by the gbinsar system in the upper part of the volcano have been used as a proxy for changes in the pressure conditions in the shallow plumbing system of stromboli volcano and hence to forecast the occurrence of phases of higher intensity volcanic activity

diel coral reef acidification driven by porewater advection in permeable carbonate sands heron island great barrier reef can play a major role in proton h cycling in a coral reef lagoon the diel ph range up to 0 75 units in the heron island lagoon was the broadest ever reported for reef waters and the night time ph 7 69 was comparable to worst case scenario predictions for seawater ph in 2100 the net contribution of coarse carbonate sands to the whole system h fluxes was only 9 during the day but approached 100 at night when small scale i e flow and topography induced pressure gradients and large scale i e tidal pumping as traced by radon seawater recirculation processes were synergistic reef lagoon sands were a net sink for h a nd the sink strength was a function of porewater flushing rate our observations suggest that the metabolism of advection dominatedcarbonatesandsmayprovideacurrently unknown feedbackto ocean acidification citation santos i r r n glud d maher d erler and b d eyre 2011 diel coral reef acidification driven by porewater advection in permeable carbonate sands heron island great barrier reef geophys res lett 38 l03604 doi 10 1029 2010gl046053

recent gravitative mass movements in a highly tectonically active arc system the hellenic arc abstract the hellenic arc system is located within one of the world s most seismically active areas and has experienced extreme tectonism throughout tertiary and quaternary times this paper discusses the various types of gravitative mass movements that have been detected and examines their causative factors in environments of high tectonic and seismic activity the areas surveyed are the sporadhes and corinth grabens in the back arc basin the zante cephalonia shelf on the inner slope of the hellenic trench and the kythera ridge in the outer island arc the various types of gravitative mass movements that have been documented include i sliding of large masses with no or only slight internal deformation ii sliding of masses with disintegration of the sediment fabric to debris flows and iii slow downslope creep the mass movements are associated with fault escarpments delta fronts and well stratified slopes with slope gradients ranging from 2 to 40 earthquakes seem to be the main mechanism initiating mass movement but other mechanisms such as increasing topographic gradient gas in the sediment pores and heavy rain can also independently trigger and or contribute to the initiation of mass movements

catastrophic collapse of the volcanic island of hierro 15 ka ago and the history of landslides in the canary islands landslides play an important role in the evolution of many volcanic islands producing huge fields of blocky volcanic debris on their submarine slopes sidescan sonar images presented in this paper provide evidence for a large debris avalanche el golfo on the northern flank of hierro island in the canary islands angular blocks as much as 1 2 km across and 200 m high cover the debris avalanche surface el golfo avalanche is related to both the canary debris flow and a volcaniclastic turbidite found in the madeira abyssal plain 600 km west of the canaries dating of the turbidite and the failure scarp onshore indicates that the failure probably occurred between 13 and 17 ka there appears to be a general correlation between volcaniclastic turbidites in the abyssal plain sequence and landslides in the canaries during the past 750 ka tentatively this correlation suggests that seven major landslides have affected the canaries in that time

bedrock sculpturing by tsunami south coast new south wales australia bedrock sculpturing resulting in s forms is associated with catastrophic flooding in near and subglacial environments produced by flow velocities approximating 10 m s 1 these velocities can also be produced by extreme tsunami generated by submarine landslides or comet impacts with oceans repetitive tsunami events during the late holocene have overwashed headlands along the new south wales south coast and produced two suites of bedrock sculptured terrain at the smaller scale s forms similar to muschelbruche v shaped grooves and sichelwannen have developed on upslopes while broad potholes flutes and transverse troughs have formed on headland crests cavitation features consisting of sinuous grooves impact marks drill holes and cavettos appear more ubiquitously at the larger scale stripped ramps large potholes cascade channels and canyon like features have been generated six flow phenomena mach stem waves jetting vortex impingement horseshoe vortices helical flow and multiple vor

tsunamis of volcanic origin summary of causes with particular reference to krakatoa 1883 known tsunamis of volcanic origin are reviewed and classified according to their causes earthquakes accompanying eruptions excluding tectonic events which apparently triggered eruptions pyroclastic flows and submarine explosions have each accounted for about 20 of cases ten causes of volcanic tsunamis are discussed from the risk point of view those due to landslides are particularly dangerous eruptions at calderas are more likely to generate tsunamis than eruptions elsewhere of those killed directly by volcanic eruptions nearly a quarter have died as a result of tsunamis by transfer of energy to sea waves a violent eruption which would be comparatively harmless on land extends greatly the radius over which destruction occurs

slope failure dynamics and impacts from seafloor and shallow sub seafloor geophysical data case studies from the costa project holocene and slightly pre holocene submarine landslide are found both in high latitude glacial dominated margins and in lower latitude river dominated margins this paper constitutes a major assessment on some of the best studied submarine instabilities in the world we review and update from original data and literature reports the current state of knowledge of storegga traenadjupet and finneidfjord slides from the mid norwegian margin afen slide from the faeroe shetland channel big 95 slide and central adriatic deformation belt cadeb from continental slope and inner continental shelf settings off the ebro and po rivers in the mediterranean sea canary slide west of the westernmost youngest canary islands and gebra slide off the northern tip of the antarctic peninsula in the southern hemisphere i e those studied in the continental slope stability costa project the investigated slides range in size from the gigantic 90 000 km2 and almost 3000 km3 storegga slide to the tiny 1 km2 and 0 001 km3 finneidfjord slide not only do individual submarine landslides rarely involve processes precisely fitting with pre established categories mostly based on subaerial research but also they display complex mechanical behaviors within the elastic and plastic fields individual events can involve simultaneous or successive vertical to translational movements including block detachment block gliding debris flow mud flow and turbidity currents the need for an in depth revision of the classification criteria and eventually for a new classification system based on the new imaging capabilities provided by modern techniques is more than obvious we suggest a new system which for the moment is restricted to debris flows and debris avalanches volume calculation methods are critically reviewed and the relations between some key geomorphic parameters are established for the selected slides the assumed volume missing from scar areas does not necessarily match the actual volume of sediment remobilised by an individual event since in situ sediment can be remoulded and eventually incorporated during the slide downslope journey cadeb a shore parallel prodelta detached from its source is the exception to the good correlation found between across slope width and alongslope length with slide area height drop measured from the headwall upper rim to its foot correlates with the debris deposit maximum thickness unless the slide moves into restricted areas which prevent farther forward expansion of the deposit such as gebra and big 95 in such cases over thickened deposits are found a particularly loose and fluid behavior can be deduced for slides showing an over thinned character such as the canary slide that traveled 600 km scar areas and slip planes have been investigated with particular emphasis although slide headwalls might present locally steep gradients up to 23 for storegga slide the slope gradients of both the failed segment margins and the main slip planes are very low max 2 and usually around 1 and less an exception is the finneidfjord slide 20 5 that occurred in 1996 because of a combination of climatic and anthropogenic factors leading to excess pore pressure and failure mechanically distinct low permeable clayey weak layers often correspond to slip planes beyond the slide headwall since not only formation of these weak layers but also sedimentation rates are climatically controlled we can state that slide pre conditioning is climatically driven too run out distances reflect the degree of disintegration of the failed mass of sediment the total volume of initially failed material and transport mechanisms including hydroplanning commonly specific run outs could be attributed to distinct elements such as cohesive blocks and looser matrix as nicely illustrated by the big 95 slide total run outs usually correspond to matrix run outs since the coarser elements tend to rest at shorter distances outrunner blocks are finally a very common feature proving the ability of those elements to glide over long distances with independence of the rest of the failed mass in addition to pre conditioning factors related to geological setting and sedimentation conditions a final trigger is required for submarine landslides to take place which is most often assumed to be an earthquake in high latitude margins earthquake magnitude intensification because of post glacial isostatic rebound has likely played a major role in triggering landslides although it cannot be totally ruled out there is little proof at least amongst the costa slides that gas hydrate destabilisation or other processes linked to the presence of shallow gas have acted as final triggers

a numerical model for the transport of a boulder by tsunami 1 we have conducted hydraulic experiments in an open channel with cubic and rectangular shaped solid blocks on the slope for investigating the boulder transport process by tsunami in our experiments the block was mainly seen to be transported by a bore due to rolling or saltation rather than by sliding previous models for the boulder transport by tsunamis assumed sliding as a mode of transport for the boulder therefore these models underestimated the distance of the boulder moved by the tsunami when it was transported due to rolling or saltation in this study we have developed a practical model for the transport of a boulder by tsunami which takes into account the various transport modes we introduce an empirical variable coefficient of friction by assuming that the coefficient decreases with decrease in ground contact time when the block was transported by rolling or saltation with the aid of this parameter the model can explain various modes of transport i e sliding rolling and saltation and reproduces the experimental results well we further applied this improved model to a tsunami boulder at inoda area in ishigaki island japan which was transported by the 1771 meiwa tsunami the calculated distance of transport of the boulder was approximately 650 m which is consistent with the description in the historical document based on our calculations we estimated hydraulic values of the tsunamis estimation of such hydraulic values is important for understanding the behavior and power of the historical tsunamis besides aiding future disaster mitigation efforts

resonance and trapping of topographic transient ocean waves generated by a moving atmospheric disturbance proudman resonance amplifies the oceanic forced wave beneath moving atmospheric pressure disturbances the amplification varies with water depth consequently the forced wave beneath a disturbance crossing topography radiates transient free waves transients are shown to magnify the effects of proudman resonance for disturbances crossing the coast or shelf at particular angles a snell like reflection law gives rise to a type of resonance for relatively slow moving disturbances crossing a coast in an otherwise flat bottomed ocean this occurs for translation speeds less than the shallow water wave speed for disturbances approaching the coast at a critical angle given by the inverse sine of the froude number of the disturbance a disturbance crossing the shelf at particular angles can also excite seiche modes of the shelf via generation of a transient at the continental slope beyond a typically small angle of incidence transients generated by a disturbance crossing the continental slope and coast will be trapped on the shelf by internal reflection the refraction law for a fast moving forced wave crossing an ocean ridge at greater than a small angle of incidence also results in trapped free wave transients with tsunami like periods propagating along the ridge the subcritical resonance excitation of shelf modes and trapping of the transients may have implications for storm surges and the generation of destructive meteotsunami

lituya bay landslide impact generated mega tsunami 50th anniversary on july 10 1958 an earthquake mw 8 3 along the fairweather fault triggered a major subaerial landslide into gilbert inlet at the head of lituya bay on the southern coast of alaska the landslide impacted the water at high speed generating a giant tsunami and the highest wave runup in recorded history the mega tsunami runup to an elevation of 524 m caused total forest destruction and erosion down to bedrock on a spur ridge in direct prolongation of the slide axis a cross section of gilbert inlet was rebuilt at 1 675 scale in a two dimensional physical laboratory model based on the generalized froude similarity a pneumatic landslide tsunami generator was used to generate a high speed granular slide with controlled impact characteristics state of the art laser measurement techniques such as particle image velocimetry piv and laser distance sensors lds were applied to the decisive initial phase with landslide impact and wave generation as well as the runup on the headland piv provided instantaneous velocity vector fields in a large area of interest and gave insight into kinematics of wave generation and runup the entire process of a high speed granular landslide impact may be subdivided into two main stages a landslide impact and penetration with flow separation cavity formation and wave generation and b air cavity collapse with landslide run out and debris detrainment causing massive phase mixing formation of a large air cavity similar to an asteroid impact in the back of the landslide is highlighted a three dimenional pneumatic landslide tsunami generator was designed constructed and successfully deployed in the tsunami wave basin at osu the lituya bay landslide was reproduced in a three dimensional physical model at 1 400 scale the landslide surface velocities distribution was measured with piv the measured tsunami amplitude and runup heights serve as benchmark for analytical and numerical models

tsunami deposits from major explosive eruptions an example from the 1883 eruption of krakatau inundation of coastal areas by tsunamis during the 1883 eruption of krakatau volcano led to the deposition of unusual pumice enriched deposits fractal analysis of pumice shapes and lithologic characterization of the deposits suggest that the source of the abundant pumiceous material was widespread pumice rafts on the surface of the sunda straits that formed by fallout and pyroclastic flow activity the rafts contained pumices rounded by particle to particle abrasion and were strongly depleted in dense components such as lithics and crystals by differential settling stranding of the floating pumice is inferred to have occurred during the receding phase of tsunamis after they had inundated low lying coastal areas other pumice bearing tsunami deposits contain significant amounts of coral fragments and nonvolcanic beach sediment these units represent redeposition of beach and shallow water sediments that were mixed with varying proportions of primary pyroclastic material the krakatau example illustrates the great diversity of lithofacies that may occur in deposits formed from volcanogenic tsunamis recognition of such deposits in coastal areas near centers of active explosive volcanism may provide an additional criterion with which to assess volcanic hazards

environmental history of the german lower rhine embayment during the middle miocene as reflected by carbon isotopes in brown coal stable carbon isotope investigations have been carried out on miocene brown coal from the garzweiler seam of the german lower rhine embayment material studied included fossil wood from seven different taxa and brown coal matrix isotope results from macrofossil analysis show variations of more than 6 within individual samples and reveal a general isotopic difference between angiosperm and gymnosperm wood specimens according to mean carbon isotope values found for gymnosperms angiosperms and brown coal matrix 23 3 26 0 and 25 8 the peat forming vegetation of the garzweiler seam was dominated by angiosperm taxa results from brown coal matrix establish a continuous high resolution depth profile of carbon isotope variations during the late middle miocene they show a significant and characteristic isotope pattern with distinct medium and short term cycles high frequency variations in the two main units of garzweiler seam locally split into three units the medium term 13c variations are most likely caused by varying proportions of gymnosperms within the peat forming vegetation while high frequency oscillations seem to be a direct signal of environmental changes a long term decline of carbon isotope values observed within the complete garzweiler seam from base to top is presumably due to a cooling trend in the miocene

linking tsunami deposits submarine slides and offshore earthquakes abstract the recognition that many tsunamis are associated with coastal sedimentation has been of great value in the study of tsunamis prehistorically geological investigation of such sediments has resulted in the identification of a series of palaeotsunamis that appear to have taken place in different areas of the world in most cases however it has proved difficult to link former tsunamis to specific source mechanisms studies of modern tsunamis have also faced difficulties in the recognition of the specific source mechanisms for example offshore earthquakes may trigger submarine slides that combine to produce complex patterns of tsunami flooding at the coast

the ad 365 crete earthquake and possible seismic clustering during the fourth to sixth centuries ad in the eastern mediterranean a review of historical and archaeological data abstract historical and archaeological data are used to test geological claims that in the fourth to sixth centuries ad the eastern mediterranean experienced an unusual clustering of destructive earthquakes the early byzantine tectonic paroxsym a review of historical accounts of a notable earthquake at this time that of 21 july ad 365 indicates that this event destroyed nearly all the towns in crete and was followed by a tsunami which devastated the nile delta the ad 365 event was also probably responsible for reported or observed destruction in ancient towns of west cyprus and libya this earthquake is most likely to be identified with a hellenic arc subduction zone event of great m 8 magnitude as testified by up to 9 m of uplift in western crete dated by previous geological studies to around this time historical and archaeological data also support the hypothesis that the fourth to sixth centuries ad was a period of abnormally high seismicity in the eastern mediterranean the high seismicity rates of this period may reflect a reactivation of all plate boundaries in the region dead sea transform east anatolian fault north anatolian fault hellenic arc cyprus arc fault

sedimentology of rocky shorelines 3 hydrodynamics of megaclast emplacement and transport on a shore platform oahu hawaii abstract megaclasts of well cemented coralgal limestone have been emplaced onto a shore platform by large waves on the north shore of oahu hi emplacement and movements of the largest ca 96 ton megaclast have been dated using aerial photographs hydrodynamic forces at the low submerged shoreline cliff are computed using design wave characteristics based on linear wave theory and experimental results considering the local wave climate and near shore bottom topography force exerted by a tsunami has been estimated based on the 1946 aleutian tsunami the computed forces are evaluated in terms of the initial fracturing along a given failure plane that is required in order for the detachment to occur the analysis shows that tsunami as well as large swell waves are capable of quarrying the megaclast provided that sufficient initial fracturing is present dislodgement and emplacement most likely occurred in a sequence during impact of a single wave on the shoreline cliff swell waves however are seldom capable of emplacing large blocks onto the platform due to their rapid disintegration after breaking so that most blocks quarried from the cliff edge fall back onto the submarine terrace emplacement of large boulders seems to require extreme sea waves with periods longer than storms or north pacific swells usually produce transport mechanisms on the shore platform vary depending on megaclast shape sliding is a common mechanism of transport for larger and irregular megaclasts whereas somewhat smaller and platy megaclasts are occasionally found in overturned positions

post depositional alteration and preservation of sedimentary event layers on continental margins i the role of episodic sedimentation the degree of post depositional alteration and hence the preservation potential of sedimentary event beds and transient signals is determined by the outcome of a race between biological and to a lesser extent physical processes that conspire to destroy a signal and sediment accumulation which advects the layer or signal out of the surface mixing zone preservation potential specifically depends on the relative magnitudes of the 1 biological mixing intensity sometimes parameterized as a biodiffusivity db 2 mixing layer thickness 3 layer or signal thickness and 4 sediment accumulation rate these terms control the dissipation time i e time required to destroy a signal and the transit time i e time necessary to advect a signal through the surface mixing layer on fine grained upper continental margins in general and the eel river shelf northern california in particular biological mixing intensity is high i e db ranges from 10 to 100 cm2 yr mixing layer thickness is large 10 cm and sediment accumulation rates are rapid 0 1 1 cm yr despite the high sediment accumulation rates transit times through the surface mixing layer range from decades to a century signal dissipation times are considerably shorter 1 3 yr for beds up to 6 cm thick imaged in x radiographs and 2 15 yr for the grain size signature of beds up to 8 cm thick therefore event layers and their corresponding grain size signature have a low probability of preservation however short lived episodic sedimentation events e g oceanic floods can instantaneously advect material through the surface mixing layer thereby preserving event beds and transient signals on the eel river shelf the sequential timing of episodic sedimentation events has exerted a first order control on the resultant stratigraphic record presence absence of layers and grain size fluctuations episodic sedimentation a hallmark of continental shelf settings is key to understanding strata formation and preservation on margins