tracing tsunami signatures of the ad 551 and ad 1303 tsunamis at the gulf of kyparissia peloponnese greece using direct push in situ sensing techniques combined with geophysical studies

applications of geochemistry in tsunami research a review abstract much progress has been made since the first published studies of tsunami deposits nearly 30 years ago geochemistry is now a much more widely used proxy in tsunami research mainly due to its increasingly recognised value in the identification of historical and or prehistorical deposits at times even providing the conclusive proof when other proxies are missing or equivocal but also its significance in environmental impact assessments following recent tsunamis the rapid advance in analytical techniques has also made it a more approachable and popular method as it is now often faster and cheaper here we provide a review of the applications of geochemistry including the techniques used as well as a database of studies that used chemical proxies in their investigation of recent and old events including onshore and offshore tsunami deposits chemical signatures are often used as markers of marine inundation either as salinity indicators where they can also allow the identification of the limit of tsunami inundation or tracers of the incorporation of marine sourced carbonates their applications as indicators of source material are nevertheless expanding thereby potentially providing additional information on the hydrodynamic processes associated with tsunami inundation although they are largely site specific the effects of post depositional changes in different climatic regimes are examined with a particular emphasis on water leachable components and implications for post event recovery of coastal ecosystems we demonstrate the usefulness of chemical proxies in studies of the geological record of tsunamis extending back thousands of years suggest new approaches and discuss limitations and existing knowledge gaps

middle to late holocene palaeoenvironmental study of gialova lagoon sw peloponnese greece abstract the coastal areas of eastern mediterranean have long been the subject of research due to their rapid geomorphological changes but also because of their archaeological interest our study is focused on a shallow coastal lagoon of peloponnese gialova lagoon which for several years has attracted the scientific interest of archaeologists geomorphologists as well as sedimentologists gialova lagoon is located near the ancient city of pylos the kingdom of king nestor during the mycenaean period 1600 1100 bc the objectives of this study are a to reconstruct the middle to late holocene depositional environments of the lagoon and b to correlate our data to already existing publications in order to shed new light on the holocene evolution of the lagoon and the associated coastal palaeoenvironmental changes an 8 m deep vibracore was drilled and a multi proxy analysis was carried out on the sediment sequence including sedimentological grain size analysis and moment measures total organic carbon toc total nitrogen tn and total phosphorus tp high resolution geochemical xrf scanning and palaeontological micro and macro faunal analysis the chronological framework is based on five 14c datings forming the basis for an age depth model calculated using the oxcal software the radiocarbon dates from previous studies 6 cores 20 dates were also taken into account the data synthesis and interpretation provided robust and coherent indications regarding the palaeoenvironment shoreline changes and the rate of geomorphological changes of the coastal area of gialova lagoon as well as useful information about the palaeonvironmental and palaeoclimatic conditions that prevailed during the mycenaean period the interpretation reveal a transition from a shallow marine environment 6500 5800 yr b p to a brackish lagoonal 5800 3300 yr b p followed by a shift towards a freshwater marsh environment 3300 yr b p to present

geo archaeological evidence for a holocene extreme flooding event within the arabian sea ras al hadd oman abstract the arabian sea is regarded as one of the least studied regions in terms of coastal hazards such as tropical cyclones and tsunamis parts of the coastline are developing rapidly especially in oman this calls for a proper understanding of the natural processes that act on and affect it this can be done by investigating the magnitude and impact of past events in particular on human settlements by doing this future risks may not only be scientifically predicted and evaluated but the damage caused by future events might even be mitigated evidence of past extreme wave events is preserved in the onshore stratigraphic record in addition to this the coastal zone of oman is rich in archaeological remains presented here are the results of comprehensive mapping and analysis of extreme wave deposits of an archaeological site near ras al hadd suggesting that the early bronze age site hd 6 was inundated at 4450 cal bp an event layer is identified between two settlement phases within the archaeological excavation a contemporaneous sand bed with a maximum thickness of 0 4 m was mapped in the vicinity of the settlement ground penetrating radar surveys allow measurement of the thickness as well as identification of the internal facies architecture of the deposit a high resolution digital elevation model reveals the coastal geomorphology it is concluded that the causative event must have been a tsunami that was most likely generated within the makran subduction zone this interpretation does however remain tentative at the moment archaeological evidence indicates that the site was immediately re occupied after the event which attests to a certain resiliences of the early bronze age coastal communities in the region

tibetan tectonic evolution inferred from spatial and temporal variations in post collisional magmatism cenozoic magmatism on the tibetan plateau shows systematic variations in space and time that must be considered in models concerning tibetan tectonic evolution after the india asia collision which started in the early tertiary and terminated the gangdese arc magmatism in the lhasa terrane made of the southern tibetan plateau widespread potassium rich lavas and subordinate sodium rich basalts were generated from f50 to 30 ma in the qiangtang terrane of northern tibet subsequent post collisional magmatism migrated southwards producing ultrapotassic and adakitic lavas coevally between f26 and 10 ma in the lhasa terrane then potassic volcanism was renewed to the north and has become extensive and semicontinuous since f13 ma in the western qiangtang and songpan ganze terranes such spatial temporal variations enable us to elaborate a geodynamic evolution model which depicts when and how the indian continental lithospheric mantle started thrusting under asia by involving rollback and breakoff of the subducted neo tethyan slab followed by removal of the thickened lhasa lithospheric root we propose that only after the lithospheric removal which occurred at f26 ma could the indian mantle lithosphere have commenced its northward underthrusting and henceforth served as a pivotal control to the himalayan tibetan orogenesis consequently the tibetan plateau is suggested to have risen diachronously from south to north whereas the southern part of the plateau may have been created and maintained since the late oligocene the northern plateau would have not attained its present day elevation and size until the mid miocene when the lower part of the western qiangtang and songpan ganze lithospheres began to founder owing to the push of the underthrust indian mantle lithosphere d 2004 elsevier b v all rights reserved

geological evidence of paleotsunamis at torre degli inglesi northeast sicily 1 two layers of fine sand of marine origin occur in a sequence of organic rich colluvia in an archaeological excavation at torre degli inglesi on capo peloro northeast sicily stratigraphic and micropaleontologic analyses support the hypothesis that these layers are related to deposition due to paleotsunami waves their ages are constrained both with radiocarbon and archaeological datings the age of the oldest layer is coincident with the 17 a d earthquake that hit reggio calabria but for which no tsunami was previously reported the age of the youngest layer can be only constrained in the range 3rd 19th century and is tentatively associated to the 6 feb 1783 event

the mw 6 3 2003 lefkada earthquake greece and induced stress transfer changes abstract a large earthquake of magnitude mw 6 3 occurred on 14 august 2003 nw of the lefkada island which is situated at the ionian sea western greece the source parameters of this event are determined using body wave modeling the focal depth was found equal to 9 km the constrained focal mechanism revealed dextral strike slip motion 15 80 and 170 the duration of the source time function was 8 s and the seismic moment 2 9 1025 dyn cm the earthquake occurred close to the northern end of the kefallinia transform fault where the 1994 moderate event and its aftershock sequence were also located the epicentral distribution of the 2003 aftershock sequence revealed the existence of two clusters the first one is located close to the epicentral area of the mainshock while the second southern close to the northwestern coast of the kefallinia island a gap of seismicity is observed between the two clusters the length of the activated zone is approximately 60 km the analysis of data revealed that the northern cluster is directly related to the mainshock while the southern one was triggered by stress transfer caused by the main event

abrupt environmental changes within a late holocene lacustrine sequence south of the marmara sea lake manyas n w turkey possible links with seismic events abstract a coring campaign in lake manyas kus golu on the southern coast of the sea of marmara turkey has provided insights into basin infilling processes during the upper 11 metres of the sedimentary record combined sedimentary features between 5 and 4 m depth have been explained by a seismite a brittle mixed layer uniquely rich in seeds and ostracod valves was widely detected at 4 m downcore this has been interpreted as being the result of a seiche either through a salt inundation linked to a tsunami in the sea of marmara the large scale scenario or a local hydrothermal fluid discharge the small scale scenario ostracod valves which are usually not preserved in lake manyas sediment are either incorporated here as tsunami debris providing a spatially averaged snapshot of the regional assemblage or are locally preserved following a temporary geochemical hydrochemical change of the water of unknown duration but probably several decades the brittle mixed layer overlies cracks resulting from the direct effects of the seismic shock wave on slightly compacted sediment at around 964 cm depth palynological and particle size analyses indicate a change from backswamp to open lacustrine conditions the end of the backswamp has been correlated with a decrease in the level of the sea of marmara from 4000 to 3000 2800 yr ago uncal caused by regional tectonic movements an age depth model is presented based on two ams radiocarbon dates on the palynological detection of the end of the beysehir occupation phase 130 cm above the event and on maximal sedimentation accumulation rates obtained by radionuclide analyses the entire study sequence covers the last 4300 yr the paper examines the possibility of an early byzantine age for the seismic event this may have been the historical event at ad 460 that destroyed cyzicus the ancient erdek 20 km north of the lake and various villages in the interior and was felt widely in the then known world other possibilities include various local and regional events in that same period the early byzantine tectonic paroxysm and the large earthquake in ad 447 that affected the entire sea of marmara region

tsunami deposits from the 1993 southwest hokkaido earthquake and the 1640 hokkaido komagatake eruption northern japan the southwest hokkaido tsunami of july 12th 1993 left continuous onshore sand deposits along the west coast of oshima peninsuka hokkaido northern japan we investigated spatial distribution and lithofacies of the new tsunami deposits for its identification of ancient tsunami deposits an eyewitness acount and bent plants helped our interpretation of the onshore tsunami behavior we regard the following properties as typical of the coastal tsunami sand deposits 1 the deposits cover the surface almost continuously on gentle topography 2 deposit thicknesses and mean grain sizes descrease with distance from the sea 3 deposit thicknesses and lithofacies vary greatly across local surface undulation 4 graded bedding reflecting tsunami runup and backwash is present in thick deposits 5 the deposits are widely distributed along the coast and extend inland several tens of meters to 100 m we examined a candidate for the paleo tsunami deposits associated with the 1640 komagatake eruption and confirmed that the similar patterns are typical of ancient tsunami deposits

geoarchaeological evidence of marshland destruction in the area of rungholt present day wadden sea around hallig sudfall north frisia germany by the grote mandrenke in 1362 ad abstract geophysical and geoarchaeological investigations were carried out in the wadden sea of north frisia schleswig holstein germany to elucidate major environmental changes that considerably altered the coastal landscape since medieval times between the 12 th and 14 th cent ad the present day tidal flats around the marsh island hallig sudfall belonged to the historical edomsharde district and its main settlement rungholt for north frisia it is well known that during medieval and early modern times extreme storm surges caused major land losses associated with a massive landward shift of the coastline today cultural traces like remains of dikes drainage ditches terps or even plough marks are still visible in the wadden sea and provide evidence of the once cultivated marshland based on a multi proxy analysis of sediment cores retrieved from the tidal flat zone around hallig sudfall and from the hallig itself we identified a late medieval paleosol associated with the formerly cultivated marshland most probably belonging to the edomsharde and local trade centre of rungholt around hallig sudfall remains of medieval marsh deposits were found partly eroded and covered by a coarse grained high energy deposit including abundant shell debris and artefacts based on sedimentological micropaleontological geochemical and geochronological data we conclude that these deposits are associated with the 1 st grote mandrenke or st marcellus flood an extreme storm surge event in 1362 ad our results for the first time provide geological evidence of this 1362 ad storm surge for the wadden sea of north frisia moreover marshland on hallig sudfall dating to the 17 th 18 th cent ad was found covered by a thick layer of storm surge sand and shell debris which seems to be associated with one of the major storm event that hit the german north sea coast in modern times e g the 2 nd grote mandrenke or burchardi flood in 1634 ad or the christmas flood in 1717 ad

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

tsunami waves generated by the santorini eruption reached eastern mediterranean shores a sedimentary deposit on the continental shelf off caesarea maritima israel is identified dated and attributed to tsunami waves produced during the late bronze age ca 1630 1550 b c e eruption of santorini greece the sheet like deposit was found as a layer as much as 40 cm thick in four cores collected from 10 to 20 m water depths particle size distribution planar bedding shell taphoecoensis dating radiocarbon optically stimulated luminescence and pottery and comparison of the horizon to more recent tsunamigenic layers distinguish it from normal storm and typical marine conditions across a wide 1 km 2 lateral area the presence of this deposit is evidence that tsunami waves from the santorini eruption radiated throughout the eastern mediterranean sea affecting the coastal people living there dates for the tsunami deposit bracket both the so called high and low chronology for the santorini eruption in addition to resolving the question of the extent of tsunami impact from the santorini eruption the research presented also provides a new means of discovering identifying and studying continuous records of paleotsunami deposits in the upper shelf coastal environment the latter is key to understanding past events better interpreting sedimentological records and creating stronger models for understanding tsunami propagation coastal management and hazard preparation worldwide

crust mantle mixing and crustal reworking of southern tibet during indian continental subduction evidence from miocene high silica potassic rocks in central lhasa block abstract collisional zones are commonly considered as important regions for crustal reworking but the reworking mechanism remains debated the well known himalayan southern tibetan orogen built by india asia collision and convergence has the thickest continental crust on earth and is therefore an ideal region for studying crustal reworking during collisional orogenesis here we revisit the miocene high silica potassic rocks trachytes in the konglong area of the central lhasa block southern tibet integrated studies of geochronology mineral compositions bulk rock major and trace element geochemistry and sr nd pb hf o isotopes unequivocally indicate that the konglong trachytes formed by mixing between enriched mantle derived ultrapotassic and thickened ancient crust derived magmas combined with post collisional magma mixing recently identified in the southern lhasa block we suggest that magma underplating and subsequent mantle crust interaction i e the matter and energy transfer from the mantle to the crust has been a common and important crustal reworking process in southern tibet during indian continental subduction this process may be related to indian plate flat subduction and subsequent foundering during the post collisional stage in combination with the nature of cenozoic magmatism in the himalaya block we suggest that in addition to partial melting of the subducted continental crust magma underplating and subsequent crust mantle mixing beneath the obducted continent has also played an important role in crustal reworking of the collisional zone

age and composition of dikes in southern tibet new constraints on the timing of east west extension and its relationship to postcollisional volcanism controversy exists over whether east west extension in southern tibet is related to plateau uplift or to the accommodation of plate boundary forces relationships between the onset of extension plateau uplift and the thermal state of the lithosphere are critical to this debate we present new data on postcollisional north south trending dikes in southern tibet their ages range from 18 3 2 7 ma to 13 3 0 8 ma and define the onset of regional east west extension in southern tibet dikes are compositionally indistinguishable from postcollisional lavas in southern tibet being either ultrapotassic having a source in the subcontinental lithospheric mantle or calc alkaline with a dominantly crustal origin the ultrapotassic dikes demonstrate that east west extension and subcontinental lithospheric mantle derived magmatism were temporally and spatially linked supporting models that relate the latest phase of plateau uplift to subcontinental lithospheric mantle thinning thus the onset of extension by 18 3 2 7 ma represents the time at which the potential energy of the plateau exceeded convergent boundary forces this places a new age limitation on the attainment of high elevation in southern tibet with implications for models that relate cenozoic monsoon intensification to plateau uplift

ground penetrating radar facies of inferred tsunami deposits on the shores of the arabian sea northern indian ocean abstract the occurrence of tsunami waves that affected the shores of the arabian sea including the gulf of oman coastline has been proven by historical reports and sedimentological investigations the damaging effect of such extensive events should not be underestimated in this region in our study we present an investigation of coarse to fine grained marine tsunami deposits in the vicinity of fins sultanate of oman using ground penetrating radar gpr the sedimentary setting along the beach section preserves evidence boulder block deposits as well as trenching results for possible high energy wave impacts the investigated area s environment is representative of conditions which lead to the best possible gpr data quality arid conditions no interference due to electrical power lines and an elevated study area 5 10 m a m s l which eliminates the low frequency noise of the ground and the possibility of salt water in the gpr data 3d visualisation of gpr results from four study areas show e g wedging out of sediments and fining inland features as well as several erosion features at the base of the deposit these findings corroborate the hypothesis of inferred tsunami deposits furthermore the presented gpr investigation technique provides new insights regarding the spatial distribution and internal architecture of palaeo tsunami deposits in comparable tsunami prone regions worldwide

ostracods as tsunami tracers in holocene sequences this review analyses the ostracod record in holocene tsunami deposits using an overview of the 2004 indian ocean tsunami impact on its recent populations and the associated tsunamigenic deposits together with results from numerous investigations of other holocene sequences different features such as the variability of the local assemblages population density species diversity age population structure e g percentages of adults and juvenile stages or taphonomical signatures suggest that these microorganisms may be included amongst the most promising tracers of these high energy events in marshes lakes lagoons or shallow marine areas

large boulder deposits by tsunami waves along the ionian coast of south eastern sicily italy abstract the ionian coast of south eastern sicily between the towns of augusta and siracusa is characterized by the occurrence of anomalous calcareous boulders they are mostly scattered along large terraces located 2 5 m above sea level gently sloping towards the sea boulders are up to 182 t in weight and are arranged either in isolated elements or small groups composed of a few stacked elements several boulders show biogenic encrustations serpulids balanids lithophaga all over their surface which suggest that they were dragged from the mid sublittoral zone other boulders are partially covered by biogenic encrustations and show morphological features karstic pools exposed fracture surfaces suggesting that they were detached and scattered from the mid supralittoral zone direct observations on each boulder distance from the shoreline size and weight together with statistical analysis of the storm regime of the area allowed to operate hydrodynamic estimations useful to verify if tsunami or storm waves were responsible for their detachment and transport while radiocarbon age determinations on marine organisms constrained the timing collected data compared to historical catalogues suggest that in the last 1000 years three seismic events with local sources could have triggered tsunami waves associated with the boulder deposits occurring in the area the first two were probably triggered by the earthquakes of february 4 1169 and january 11 1693 which destroyed south eastern sicily according to geological data and numerical modelling the seismogenic source could be located in the ionian offshore between catania and siracusa the third tsunami was generated by the strong earthquake which took place in the strait of messina on december 28 1908

large boulder accumulation on the algerian coast evidence tsunami events in the western mediterranean abstract evidence of catastrophic mega block deposition is presented for the algerian coast from tipaza to dellys the region is prone to large earthquakes several of which are inferred to be tsunamigenic in origin as attests the 2003 zemmouri earthquake mw 6 8 it is argued here that several former tsunamis have resulted in the detachment of large boulders from the nearshore zone and their deposition inland the estimated size weight volumetric mass and distance from the shoreline of more than 100 boulders has enabled estimates to be made of the nature of the hydrodynamic waves responsible for their transport the boulders weigh up to 200 tons and are scattered along 150 km of rocky headlands and pocket beaches in isolated or grouped elements from the subtidal to supratidal zones boulders covered by biogenic incrustations show morphological features which suggest detached reversed and reworked pieces statistical and hydrodynamic analyses indicate that large boulder transport requires either 30 m high waves or 5 to 10 m high waves for catastrophic storm or tsunami events respectively bio indicators allow us to date two inferred tsunamis as having struck the algerian coastline between ad 400 600 and ad 1700

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

high resolution record of export production in the eastern equatorial pacific across the eocene oligocene transition and relationships to global climatic records 1 understanding changes in export production through time provides insight into the response of the biological pump to global climate change particularly during periods of rapid climate change in this study we consider what role changes in export production may have had on carbon sequestration and how this may have contributed to the onset of the eocene oligocene transition eot in addition we consider if these export production variations are dominantly controlled by orbitally driven climate variability to accomplish these objectives we report changes in export production in the eastern equatorial pacific eep from site u1333 across the eot reconstructed from a high resolution record of marine barite accumulation rates bar bar fluctuations suggest synchronous declines in export production associated with the two step increases in oxygen isotopes that define the transition the reduction in productivity across the eot suggests that the biological pump did not contribute to carbon sequestration and the cooling over this transition we also report a previously undocumented peak in eep export productivity before the eot onset this peak is consistent with export production proxies from the southern ocean potentially implying a global driver for this precursor event we propose that this enhanced export production and the associated carbon sequestration in the late eocene may have contributed to the pco2 drawdown at the onset of antarctic glaciation

pn uppermost mantle tomography of central tibet implication for mechanisms of n s rifts and conjugate faults abstract the north south convergence between the indian and eurasian continents since cenozoic has produced the tibetan plateau and east west extension structures have also developed since late cenozoic whether these extensional structures are limited to the crust or extend to the deep lithosphere remains controversial the uppermost mantle serves as a link between the crust and deep lithosphere the velocity structure of which provides an important constraint on exploring the mechanism of extensional structures based on pn traveltime data recorded by the sandwich network in central tibet we use the interstation traveltime difference method to obtain the uppermost mantle velocity structure our results show significant velocity differences for the uppermost mantle beneath the conjugated strike slip faults and rifts which indicates their different formation mechanisms the high pn velocity beneath the conjugated strike slip faults support an eastward horizontal shear at the base of the upper crust rather than the lower crust has contributed to the development of the conjugated strike slip faults the low pn velocity beneath the rifts in lhasa may provide evidence for the rifts cutting through the entire crust and reflect the connection between the formation of the rifts and deep tectonic activities the most prominent features in our results are the low pn velocity zones beneath the tangra yum co rift tyr the pumqu xianza rift pxr and the zone between the two rifts and we explain the low pn velocity as the top of the mantle wedge upon the subducting indian lithospheric slab

mid holocene tectonic geomorphology of northern crete deduced from a coastal sedimentary archive near rethymnon and a late bronze age santorini tsunamite candidate abstract the late bronze age lba tsunami and the a d 365 tsunami are supposed to have affected the northern coasts of crete however near coast sedimentary archives have been rarely investigated in this area and sedimentary archives including palaeotsunami fingerprints are still unknown the main objective of our research was to search for appropriate tsunami sediment traps in order to gain detailed insights into the holocene palaeotsunami history of northern crete we found an excellent fine sediment archive near pirgos located to the west of rethymnon based on a multi electrode geoelectrical survey and an 11 m deep sediment core we analysed the event geochronostratigraphical record by means of sedimentological geochemical geochronological geomorphological and microfossil investigations the pirgos record revealed a thick unit of homogeneous mud of a lagoonal environment starting 6000 years ago the lagoon was affected by five high energy events leaving layers of allochthonous sand microfossil analyses of these layers revealed a mixed foraminiferal assemblage including species from brackish habitats but also displaced and transported species from open marine and deep water environments considering sedimentary characteristics the local wave climate of the cretan sea and the overall geomorphological setting we interpret these layers as related to extreme wave events ewe based on a local radiocarbon age depth model we identified one ewe layer as a reliable candidate for the lba santorini tsunami another ewe layer is most probably associated with the a d 365 tsunami this ewe ended abruptly the lagoonal conditions at pirgos because of to the 1 64 m coseismic uplift at the site the pirgos lagoon existed between the first half of the 6th mill b c and at least the end of the 2nd mill b c we found that the area around pirgos has continuously subsided over 3000 or so years reflecting constant tectonogeomorphological conditions dominated by the nearby subduction zone between the aegean and african plates

historical and pre historical tsunamis in the mediterranean and its connected seas geological signatures generation mechanisms and coastal impacts abstract the origin of tsunamis in the mediterranean region and its connected seas including the marmara sea the black sea and the sw iberian margin in the ne atlantic ocean is reviewed within the geological and seismotectonic settings of the region a variety of historical documentary sources combined with evidence from onshore and offshore geological signatures geomorphological imprints observations from selected coastal archeological sites as well as instrumental records eyewitnesses accounts and pictorial material clearly indicate that tsunami sources both seismic and non seismic e g volcanism landslides can be found in all the seas of the region with a variable tsunamigenic potential local regional and basin wide tsunamis have been documented an improved map of 22 main tsunamigenic zones and their relative potential for tsunami generation is presented from west to east the most important tsunamigenic zones are situated offshore sw iberia in the north algerian margin in the tyrrhenian calabria and messina straits in the western and eastern segments of the hellenic arc in the corinth gulf of central greece in the levantine sea offshore the dead sea transform fault and in the eastern side of the marmara sea important historical examples including destructive tsunamis associated with large earthquakes are presented the mean recurrence of strong tsunamis in the several basins varies greatly but the highest event frequency 1 96 years is observed in the east mediterranean basin for most of the historical events it is still unclear which was the causative seismic source and if the tsunami was caused by co seismic slip by earthquake triggered submarine landslides or by a combination of both mechanisms in pre historical times submarine volcanic eruptions i e caldera collapse massive pyroclastic flows volcanogenic landslides and large submarine landslides caused important tsunamis although little is known about their source mechanisms we conclude that further investigation of the tsunami generation mechanisms is of primary importance in the mediterranean region inputs from tsunami numerical modeling as well as from empirical discrimination criteria for characterizing tsunami sources have been proved particularly effective for recent well documented aseismic landslide tsunamis e g 1963 corinth gulf 1979 cote d azur 1999 izmit bay 2002 stromboli volcano since the tsunami generation mechanisms are controlled by a variety of factors and given that the knowledge of past tsunami activity is the cornerstone for undertaking tsunami risk mitigation action future interdisciplinary research efforts on past tsunamis are needed

on the cause of the 1908 messina tsunami southern italy 1 a century after the catastrophic event the sources of the 1908 messina southern italy earthquake and tsunami which caused at least 60 000 deaths remain uncertain through a simple backward ray tracing method we convert the tsunami travel time data reported in a 100 years old paper into distances and find that the sources of the earthquake and tsunami are different overturning a long held assumption reconsideration of the available tsunami bathymetric seismic and seismological data indicates that the tsunami was generated by an underwater landslide

the 1956 earthquake and tsunami in amorgos greece summary we conduct a comprehensive study of the amorgos greece earthquake and tsunami of 1956 july 09 the largest such event in the aegean sea in the 20th century systematic relocation of the main shock and 34 associated events defines a rupture area measuring 75 40 km the use of the preliminary determination of focal mechanism algorithm resolves the longstanding controversy about the focal geometry of the event yielding a normal faulting mechanism along a plane dipping to the southeast which expresses extensional tectonics in the back arc behind the hellenic subduction zone the seismic moment of 3 9 10 27 dyn cm is the largest measured in the past 100 yr in the mediterranean basin a quantitative database of 68 values of tsunami run up was built through the systematic interview over the past 5 yr of elderly eyewitness residents of 16 aegean islands and the turkish coast of asia minor it confirms values of up to 20 m on the southern coast of amorgos 10 m on astypalaia and up to 14 m on the western coast of folegandros 80 km to the west of the epicentre these values largely in excess of the inferred seismic slip at the source and their concentration along isolated segments of fault are incompatible with the generation of the tsunami by the seismic dislocation and require an ancillary source in the form of a series of landslides triggered by the earthquake and or its main aftershocks a model confirmed by hydrodynamic simulations using both the dislocation source and models of landslide sources

geoarchaeological investigations of a prominent quay wall in ancient corcyra implications for harbour development palaeoenvironmental changes and tectonic geomorphology of corfu island ionian islands greece abstract in antiquity the harbour city of corcyra modern corfu was a prevailing naval power in the mediterranean and had several harbours to host a considerable fleet today these harbours are totally or partly silted and concealed under modern urban infrastructure comprehensive geoarchaeological studies were conducted on the northeastern fringe of the analipsis peninsula where excavations have revealed the archaeological remains of a massive quay wall pierri and arion sites these remains are located east of known ancient harbour structures that belong to the alkinoos harbour our study aimed to reconstruct the palaeoenvironmental setting of the harbour facilities at the pierri site including the analysis of the local sedimentary record in order to detect and differentiate natural and man made triggers that caused environmental shifts at the pierri site we found geoarchaeological evidence for an ancient harbour basin related to the prominent quay wall associated harbour sediments indicate a protected harbour which was developed from an open shallow marine environment most probably by the construction of breakwaters harbour deposits were dated using radiocarbon analyses and diagnostic ceramic fragments to the 4 th to 3 rd cent bc this is in good agreement with the age of the harbour installations as such archaeologically assigned to the classical and hellenistic period the pierri site was possibly in function as a harbour facility even before the 4th cent bc in any case it was strongly hit by an earthquake and associated tsunami event during classical to hellenistic times by this event the harbour was uplifted and covered by event deposits so that it was not usable any more it was subsequently buried by anthropogenic and colluvial sediments overall the pierri coastal archive allowed to identify three distinct tsunami landfall events namely before 2483 2400 cal bc event i after 2483 2400 cal bc and before 370 214 cal bc event ii and during classical to hellenistic times most probably between the 4 th and 3 rd cent bc event iii another tsunami event event iv potentially hit the site when it was dry land ages of tsunami events i ii and candidate tsunami iv are consistent with tsunamis known from the coasts of western greece and southern italy and where thus classified as supra regional tele events event iii was identified as associated to a local earthquake and tsunami by which corfu island was uplifted and at the same time tilted with a vertical offset of 1 74 m from w to e

relative sea level changes and regional tectonic evolution of seven coastal areas in nw greece since the mid holocene abstract this study presents relative sea level rsl curves for seven coastal areas in akarnania and the northwestern peloponnese nw greece since the mid holocene rsl fluctuations are deduced from 48 14c ams dated sedimentological sea level markers from 27 vibracores drilled in near coast geological archives as well as from six geoarchaeological sea level indicators of known ages seven palaeo sea level curves including uncertainty bands are reconstructed for a coastal zone spanning a distance of 150 km considerable intra regional differences in sea level evolution exist these differences are mainly due to tectonic reasons in general rsl in northwestern greece has never been higher than today rates of local sea level rise were highest until 5500 5000 cal bc up to 12 3 m ka and lowest during 4000 500 cal bc 0 2 1 4 m ka during the past 2500 or so years rsl has accelerated anew 0 7 2 7 m ka calculating differences between local mean sea level curves provides quantitative information on intra regional differences of tectonic activity the coastal plains of palairos and elis show signs of uplift whereas the mytikas and boukka plains are strongly subsiding compared to other areas of the eastern mediterranean northwestern greece has been subject to significant net long term subsidence regional tectonic events rtes were detected for the time around 4000 2500 500 and 250 cal bc as well as around 250 and 1250 cal ad rtes are characterized by changes of uplift subsidence rates or by the redirection of local tectonic movements the question if some of the rtes were of a supra regional nature is still open from a geodynamic point of view the results presented show that akarnania s southwestern fringe is being downwarped while the tectonic block as a whole is moving towards the southwest strongest subsidence rates are observed for central akarnania at akarnania s fringes subsidence is reduced by the influence of strong uplift of adjacent areas such as around preveza and the northern peloponnese

properties of the 2003 lefkada ionian islands greece earthquake seismic sequence and seismicity triggering on 14 august 2003 lefkada island central ionian was strongly af fected by an mw 6 2 earthquake a dense temporary seismic network was installed one day after and accurately located hundreds of aftershocks that defined in detail the main rupture as well as the activity distribution in the neighboring fault segments the main rupture occupied the northwestern part of the coastline and trends north northeast south southwest in agreement with regional tectonics regional network locations were appropriately calibrated using the local network data allowing the relocation of the mainshock and strong m 4 5 or larger aftershocks during the first day intense aftershock activity took place up to 40 km beyond the southern end of the main rupture theoretical static stress changes from the mainshock give a preliminary explanation for the aftershock distribution aside from the main rupture as well as triggering of seismicity in the nearby kefalonia fault providing evidence for future seismic hazard ensuing from this fault

impact of holocene tsunamis detected in lagoonal environments on corfu ionian islands greece geomorphological sedimentary and microfaunal evidence abstract in this paper we present for the first time geomorphological sedimentary and microfaunal evidence of palaeotsunami impact on corfu ionian islands greece the island of corfu is located in an area of exceptional tectonic stress towards the south the african oceanic plate is being subducted underneath the aegean plate whereas towards the north the adriatic and european plates form a continental collision zone recent publications provide evidence of earthquake related co seismic movements that potentially trigger extreme wave events as well as relative sea level fluctuations in this context we investigated two selected near coast geological archives the chalikiopoulou lagoon in the east and the korission lagoon in the southwest of corfu island our results clearly document that the eastern as well as the southwestern coasts of corfu were repeatedly affected by palaeotsunami impact during the holocene with regard to the local topographical constellation and the recent geomorphodynamic potential of each study area evidence of high energy wave impact is based on the stratigraphical and microfaunal record of selected vibracoring sites as well as on numerical modelling results it is concluded that the eastern coast of corfu is preferably affected by high energy wave impacts from a southern direction such impacts are most likely related to teletsunamis from the major seismical zone of the hellenic trench in contrast the southwestern coast of corfu is endangered by impacts from both western and southern directions such impacts may comprise teletsunamis triggered in the hellenic trench or the etna regions but may also be caused by local submarine landslides at the steeply sloping continental shelf directly west of corfu our study builds a bridge between palaeotsunami research conducted in the southern ionian sea and the adriatic sea and allows to better discriminate between the effects of teletsunamis and locally triggered events within one of the seismically most active regions in the eastern mediterranean

reconstruction of paleostorm events in a coastal lagoon herault south of france article i nfo finding records of past catastrophic storm events is essential to evaluate the long term climatic evolution in a given coastal area this question has been addressed by the study of sediment cores sampled in a small coastal lagoon of the french mediterranean coast pierre blanche lagoon two cores were studied in detail and revealed the presence of three main storm events the sedimentation rates calculated using the cfcs 210 pb model in agreement with 137 cs data are 3 0 4 and 4 2 0 7m m y 1 near the border and in the center of the lagoon respectively this suggests that the 0 6 m deep lagoon could be filled with sediments over the next 150 yr our study shows that storm events can be characterized in sedimentary sequences identified by facies grain size and faunal assemblages lagoonal and marine species comparison of 210 pb 14 c chronology and historical accounts suggest that the three identified

distinction between the storegga tsunami and the holocene marine transgression in coastal basin deposits of western norway many coastal lakes were inundated by both the storegga tsunami 7000 14 cy r bp and the mid holocene sea level rise the tapes transgression in western norway the tsunami eroded lake bottoms and deposited graded and or massive beds of sand rip up clasts and coarse plant material by contrast when the rising sea entered the lakes it deposited only gyttja silt and fine sand without causing much erosion of the underlying lake sediments storegga tsunami deposits in some coastal lakes were interpreted previously as ordinary marine sediments from the tapes transgression our reinterpretation of these deposits shows that the transgression maximum phase was reached after 6500 yr bp more than 1000 yr later than previously inferred for the coast of sunnmore the new data cannot be combined in a shoreline diagram without showing the 6000 yr bp and 7000 yr bp shorelines as slightly warped 1998 john wiley sons ltd

tracking mid to late holocene depositional environments by applying sedimentological palaeontological and geochemical proxies amvrakikos coastal lagoon sediments western greece mediterranean sea abstract this study presents sedimentological palaeontological geochemical mineralogical and organic petrography data from a 30 m deep core representing a mid to late holocene lagoonal depositional environment of a coastal area of amvrakikos gulf western greece three horizons were dated using 14c the sedimentological palaeontological and geochemical interpretations of the lagoonal sediments reveal three major lithological units deposited between around 5200 and 1600 bp the upper lithological unit extended to a depth of 11 20 m the middle from 11 20 to 21 30 m and the lower one from 21 30 to 30 00 m a mean rate of sedimentation of 5 7 mm y and a maximum rate of 12 6 mm y were estimated the mineralogical analysis and the magnetic susceptibility of the core points to a constant sediment source supply the mid to late holocene depositional environment mainly reflects inundation by the braid plain of the arachthos and secondarily by the louros river the reconstruction of the depositional environments corresponds to a shallow marine and deltaic brackish lagoon and specifically to an environment proximal to river supply the high rates of sedimentation as well as the interpretation of depositional environments indicate that the coastal sedimentological processes during the mid to late holocene were mainly controlled by the progradation of river deltas moreover the geochemical proxies the recovered molluscs and the microfauna as well as the organic petrography analyses indicate periods of dysoxic and hypoxic conditions these holocene dysoxic and hypoxic events indicate that the recent dystrophic crises in the amvrakikos gulf are not only the result of human activities but also the contribution of natural processes

geoarchaeological tsunami deposits at palaikastro crete and the late minoan ia eruption of santorini abstract the explosive eruption at santorini in the aegean sea during the second millennium bce was the largest holocene volcanic upheaval in the eastern mediterranean region the eruption was disastrous for the minoan settlements at santorini but the effect on human society in the neighbouring islands and regions is still clouded in uncertainty tsunami generation was suggested but comparatively little evidence was found the lack of firm tsunami traces is particularly puzzling in crete with its coastal settlements of the late minoan ia period during which the santorini eruption occurred here we report the discovery of extensive geoarchaeological tsunami deposits at palaikastro in north eastern crete these deposits are characterized by a mixture of geological materials including volcanic santorini ash and archaeological settlement debris various tsunami signatures were identified 1 erosional contact with the underlying strata 2 volcanic ash intraclasts in the lower part of the deposit 3 reworked building stone material in the lower part of the deposit 4 individual marine shells 5 marine micro fauna 6 imbrication of rounded beach pebbles settlement debris ceramic sherds and even bones 7 multi modal chaotic composition late minoan human settlement activities at palaikastro provided architectural and stratigraphic frameworks in space and time that recorded and preserved tsunami evidence as geoarchaeological deposits such stratigraphic resolution and preservation may not occur in the natural landscape volcanic ash transported by wind from santorini south east to crete preceded the tsunami geological archaeological and radiocarbon dating criteria all converge indicating that the tsunami deposits are coeval with the minoan santorini eruption field evidence suggests that tsunami waves at palaikastro were at least 9 m high inverse tsunami modeling was attempted based on these newly discovered tsunamigenic deposits the initial wave in the generation region at santorini that best fits the stratigraphic data is a wave with 35 to 15 m initial amplitude and a crest length of about 15 km

onshore tsunami deposits caused by the 1993 southwest hokkaido and 1983 japan sea earthquakes onshore tsunami deposits resulting from the 1993 southwest hokkaido and 1983 japan sea earthquakes were described to evaluate the feasibility of tsunami deposits for inferring paleoseismic events along submarine faults tsunami deposits were divided into three types based on their composition and aerial distribution a deposits consisting only of floating materials b locally distributed siliclastic deposits and c widespread siliclastic deposits the most widely distributed tsunami deposits consist of the first two types type c deposits are mostly limited to areas where the higher tsunami runup was observed the scale of tsunami represented by vertical tsunami runup is an important factor controlling the volume of tsunami deposits the thickest deposits about 10 cm occur behind coastal dunes to produce thick siliclastic tsunami deposits a suitable source area such as sand bar or dune must be available in addition to sufficient vertical tsunami runup estimation of the amounts of erosion and deposition indicates that tsunami deposits were derived from both onshore and shoreface regions the composition and grain size of the tsunami deposits strongly reflect the nature of the sedimentary materials of their source area sedimentary structures of the tsunami deposits suggest both low and high flow regimes consequently it seems very difficult to identify tsunami deposits based only on grain size distribution or sedimentary structure of a single site in ancient successions

revision of the timing magnitude and distribution of neogene rotations in the western aegean region to evaluate the dimension and the timing of the clockwise rotating domain and the nature of the structures that accommodate the rotating domain in the western aegean region paleomagnetic analyses were carried out in northern western and southwestern greece the results show that the rotating domain covers an area including the external albanides western mainland greece including evia and probably at least partly the peloponnesos smaller clockwise rotations on the order of 30 408 were reported previously from the chalkidiki peninsula and the islands of skyros and limnos previously two phases of approximately 258 of rotation were suggested the last one during the plio pleistocene our analysis shows that the western aegean domain rotated approximately 408 clockwise between 15 13 and 8 ma followed by an additional 108 after 4 ma the rotating domain is accommodated in the north by deformation associated with the scutari pec fault zone and in the west by the ionian thrust and the hellenic subduction zone to the south no rocks older than 10 ma are available so no conclusive data are obtained to the east of the rotating domain extensional detachment systems of the cyclades and rhodope areas were active during the rotation phase and may explain at least part of the differences in finite amounts of rotation between nonrotation or counterclockwise rotations observed in northern and eastern greece and the large clockwise rotations in western greece d 2004 elsevier b v all rights reserved

coastal sedimentation associated with the december 26 2004 tsunami in lhok nga west banda aceh sumatra indonesia abstract with wave heights of 30 m and runups reaching 50 m a s l and 6 km inland the december 26 2004 tsunami in sumatra was one of the largest tsunamis in recorded human history in this paper we present a description of the event in the lhok nga bay west coast of banda aceh and an interpretation of the tsunami sand deposits mostly based upon grain size analysis the 3 5 km long transect of lampuuk displays two landward fining thinning and sorting sequences the thickest cross sections of the first sequence of deposits 0 1 5 km inland suggest a deposition by three consecutive runups inflows and a final backwash return flow or outflow from 1 5 to 3 5 km inland the record is dominated by the second and highest wave 15 30 m normally graded couplets or triplets of layers were used to identify the runup of each wave the topmost layers interpreted as the backwash deposition describe a seaward sequence of increasing mean grain size and decreasing degree of sorting the local effects of the topography could be identified thickest deposits in the topographic lows 50 80 cm great spatial variations in thickness and upper laminated texture when the sedimentation was limited by steep slopes landward coarsening and very poor sorting at the wave breaking point bimodal grain size distributions reflecting different sources of sediments finally by coupling the longitudinal and vertical trends of the 26 cross sections we propose a model of sediment transport and deposition in a large tsunami wave

coastal sedimentation associated with the december 12th 1992 tsunami in flores indonesia this paper presents the result of a detailed granulometric investigation of sediments deposited by a modern tsunami the 1992 tsunami in flores indonesia eyewitness accounts indicate that sediments were deposited upon coastal lowlands over wide areas as a result of the tsunami inundation distinctive vertical and lateral variations in particle size composition are characteristic features of the tsunami deposits and these are intimately related to sedimentary processes associated with flood inundation the geomorphological and sedimentary evidence is used here to establish a preliminary model of tsunami sedimentation this information is believed to be of great value in understanding sedimentary processes associated with tsunami flooding and in the interpretation of palaeo tsunami deposits

a late holocene record of environmental changes from the aliki lagoon egion north peloponnesus greece abstract aliki lagoon is a small lagoon located on the micro tidal south coast of the gulf of corinth greece the sediments of the lagoon recovered in three cores provide a record of late holocene environmental change including tectonic subsidence tsunami layers and change in local vegetation and sedimentation four periods of rapid environmental changes were identified over a 5000 yr long record these date from about 4700 3000 2500 and 2000 yr bp each change is linked to activity on the egion fault a deepening of the lagoonal bottom and a rise in relative sea level six tsunami events are recorded and have been caused by earthquakes on the egion fault three events 4700 3000 and 2500 bp eliki fault 2350 40 yr bp and two more distal fault ruptures the vegetation history and pollen zones are similar to those recognised by jahns vegetation hist archaebot 2 1993 187 on the argive plain 100 km southeast of the lagoon five successive sedimentological configurations are established in relation to the time frame provided by the tectonic activity 1 crevasse splay 2 fresh to brackish water marsh 3 and 4 brackish to hypersaline blind lagoon and 5 brackish to hypersaline blind lagoon or brackish open lagoon

mantle inputs to himalayan anatexis insights from petrogenesis of the miocene langkazi leucogranite and its dioritic enclaves abstract oligocene and miocene himalayan anatexis is generally thought to have been induced by intracrustal heating or processes without the involvement of mantle derived heat and materials suggesting that the himalayan leucogranites are typical examples of purely crustal melts this study focuses on a miocene leucogranite at langkazi within the himalayan orogen an intrusion that contains a large number of dioritic enclaves these enclaves have typical igneous textures contain acicular apatites and have back veining structures quenched margins and crystallization ages identical to the hosting two mica granites indicating that these enclaves are magmatic although the enclaves are evolved the most primitive samples contain high concentrations of mgo up to 4 3 wt cr up to 159 ppm and ni up to 102 ppm are strongly enriched in large ion lithophile elements are depleted in high field strength elements have negative e nd t values 8 6 to 6 1 and have relatively high 87 sr 86 sr i values 0 7085 0 7137 suggesting that they were derived from a relatively enriched region of the lithospheric mantle source whole rock geochemical data indicate that the hosting langkazi leucogranite formed from magmas generated by the partial melting of metapelite material within the high himalaya crystalline sequence and these magmas subsequently mixed with mantle derived melts that are now represented by the langkazi dioritic enclaves this indicates that mantle derived material played an important role in the generation of the langkazi intrusions the whole rock geochemical compositions of samples from the study area also indicate that the primary melts that formed the langkazi enclaves were significantly contaminated by the relatively juvenile himalayan lower crustal material suggesting in turn that these mantle derived magmas underwent mash crustal melting melt assimilation magma storage and homogenization processes at the base of crust introducing heat to the lower crust this mantle derived heat may have induced partial melting of the himalayan lower crust forming adakite like magmas although the small volumes of these dioritic enclaves suggest that this heat may have assisted the genesis of the north himalayan granites and the high himalayan leucogranites whereas in situ crustal radiogenic heating shear heating and decompression melting dominated the melting processes in this region

eastern mediterranean tectonics and tsunami hazard inferred from the ad 365 earthquake historical accounts describe an earthquake and tsunami on 21 july ad 365 that destroyed cities and drowned thousands of people in coastal regions from the nile delta to modern day dubrovnik the location and tectonic setting of this earthquake have been uncertain until now here we present evidence from radiocarbon data and field observations that western crete was lifted above sea level by up to 10 m synchronously with the ad 365 earthquake the distribution of uplift combined with observations of present day seismicity suggest that this earthquake occurred not on the subduction interface beneath crete but on a fault dipping at about 30 within the overriding plate calculations of tsunami propagation show that the uplift of the sea floor associated with such an earthquake would have generated a damaging tsunami through much of the eastern mediterranean measurement of the present rate of crustal shortening near crete yields an estimate of 5 000 yr for the repeat time of tsunamigenic events on this single fault in western crete but if the same process takes place along the entire hellenic subduction zone such events may occur approximately once every 800 yr in the year ad 365 an earthquake and tsunami destroyed much of the eastern mediterranean coastal regions the distribution of uplift at the time suggests that the earthquake occurred on a fault within the overriding plate at the subduction zone beneath crete and not on the subduction interface itself

clay minerals and geochemistry record from northwest mediterranean coastal lagoon sequence implications for paleostorm reconstruction abstract the paleostorm history of coastal lagoon environments pierre blanche lagoon central part of the gulf of lions has been established by integrating clay mineralogy and geochemical analysis clay mineralogy combined with bulk major and trace elements concentrations allow for the definition of four different end members the mosson drainage basin the sandy barrier the biogenic and the anthropic components the two main sedimentary sources of the lagoonal system are the mosson drainage basin which has a high concentration of smectite and al 2 o 3 and the sandy barrier characterized by high contents of illite chlorite sio 2 and zr smectite illite chlorite sio 2 al 2 o 3 and zr al 2 o 3 ratios can be used to reconstruct the past storm history of the pierre blanche lagoon our results indicate that the sensitivities of the clay mineralogy and geochemistry proxies are different these sensitivities could be related 1 first to the comparison between different grain size for geochemistry and for clay mineralogy 2 second to the complexity of the mix four end members for the geochemistry and two end members for the clay minerals and 3 third by the storm s ability to transport sediment of different sizes

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

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

implications of shortening in the himalayan fold thrust belt for uplift of the tibetan plateau 1 recent research in the himalayan fold thrust belt provides two new sets of observations that are crucial to understanding the evolution of the himalayan tibetan orogenic system first u pb zircon ages and sm nd isotopic studies demonstrate that 1 greater himalayan medium to high grade metasedimentary rocks are much younger than true indian cratonic basement and 2 these rocks were tectonically mobilized and consolidated with the northern margin of gondwana during early paleozoic orogenic activity these observations require that greater himalayan rocks be treated as supracrustal material in restorations of the himalayan fold thrust belt rather than as indian cratonic basement in turn this implies the existence of greater himalayan lower crust that is not exposed anywhere in the fold thrust belt second a regional compilation of shortening estimates along the himalayan arc from pakistan to sikkim reveals that 1 total minimum shortening in the fold thrust belt is up to 670 km 2 total shortening is greatest in western nepal and northern india near the apex of the himalayan salient and 3 the amount of himalayan shortening is equal to the present width of the tibetan plateau measured in an arc normal direction north of the indus yalu suture zone this information suggests that a slab of greater indian lower crust composed of both indian cratonic lower crust and greater himalayan lower crust with a north south length of 700 km may have been inserted beneath the tibetan crust during the cenozoic orogeny we present a modified version of the crustal underthrusting model for himalayan tibetan orogenesis that integrates surface geological data recent results of mantle tomographic studies and broadband seismic studies of the crust and upper mantle beneath the tibetan plateau previous studies have shown that incremental mesozoic and early cenozoic shortening had probably thickened tibetan crust to 45 55 km before the onset of the main cenozoic orogenic event thus the insertion of a slab of greater indian lower crust with maximum thickness of 20 km tapering northward could explain the cenozoic uplift of the tibetan plateau the need for tibetan crust to stretch laterally as the greater indian lower crust was inserted may explain the widespread east west extension in the southern half of the plateau our reconstruction of the himalayan fold thrust belt suggests that indian cratonic lower crust of presumed mafic composition and high strength should extend approximately halfway across the tibetan plateau to the banggong suture from there northward we predict that the tibetan plateau is underlain by more felsic and therefore weaker lower crust of greater himalayan affinity two slab break off events are predicted by the model the first involved neotethyan oceanic lithosphere that foundered 45 35 ma and the second consisted of greater indian lithosphere most likely composed of greater himalayan material that delaminated and foundered 20 10 ma asthenospheric upwelling associated with the break off events may explain patterns of cenozoic volcanism on the tibetan plateau although the model predicts a northward migrating topographic front due solely to insertion of greater indian lower crust the actual uplift history of the plateau was complicated by early middle tertiary shortening of tibetan crust

discovery of minoan tsunami deposits the hellenic arc is a terrane of extensive quaternary volcanism one of the main centers of explosive eruptions is located on thera santorini and the eruption of the thera volcano in late minoan time 1600 1300 b c is considered to have been the most significant aegean explosive volcanism during the late holocene the last eruptive phase of thera resulted in an enormous submarine caldera which is believed to have produced tsunamis on a large scale evidence suggesting seawater inundation was found previously at some archaeological sites on the coast of crete however the cause of the tsunami and its effects on the area have not been well understood on the aegean sea coast of western turkey didim and fethye and crete gouves we have found traces of tsunami deposits related to the thera eruption the sedimentological consequences and the hydraulics of a thera caused tsunami indicate that the eruption of thera volcano was earlier than the previous estimates and the tsunami did not have disruptive influence on minoan civilization

the generation and preservation of multiple hurricane beds in the northern gulf of mexico abstract cores collected from mississippi sound and the inner shelf of the northeast gulf of mexico have been examined using 210 pb and 137 cs geochronology x radiography granulometry and a multi sensor core logger the results indicate that widespread event layers were probably produced by an unnamed hurricane in 1947 and by hurricane camille in 1969 physical and biological post depositional processes have reworked the event layers producing regional discontinuities and localized truncation and resulting in an imperfect and biased record of sedimentary processes during the storms the oceanographic and sedimentological processes that produced these event beds have been simulated using a suite of numerical models 1 a parametric cyclone wind model 2 the swan third generation wave model 3 the adcirc 2d finite element hydrodynamic model 4 the princeton ocean model 5 a coupled wave current bottom boundary layer sedimentation model and 6 a model for bed preservation potential as a function of burial rate and bioturbation rate simulated cores from the mississippi sound region are consistent with the observed stratigraphy and geochronology on both the landward and seaward sides of the barrier islands

structural controls on basin evolution neogene to quaternary of the ionian zone western greece turbidite deposition of oligocene to early miocene age occurred in the foreland basin to the pindus mountains which formed the nnw trending hellenide thrust front deposition was interrupted by the migration of the deformation front westwards through the foreland basin itself the kalamitsi thrust exposed in west levkas became active in late early miocene times a miocene to pliocene piggy back basin developed fed both from the thrust front to the west and the mountain belt to the east during the mid late miocene deformation remained confined to the ionian and gavrovo zones possibly related to the presence of lubricating evaporites which terminate in the pre apulian zone to the west during the late plio quaternary inner arc extension trenchward of the hellenic arc caused a system of ene and wnw basins to open under the n s tensional regime these were linked by nnw and ne transtensional faults and the system is still active in the lake trikhonis and gulf of corinth areas today in the west of the study area however post pliocene nw se compressional faults dissected the piggy back basin this compressional phase must have been either contemporaneous with or interrupted the extension active in the east from late pliocene times

sedimentation and hydrodynamic processes associated with the tsunami generated by the 1755 lisbon earthquake abstract an unusual sedimentary horizon believed to have been deposited by the tsunami associated with the 1755 lisbon earthquake has been identified at boca do rio in southern portugal this horizon marks a distinct sedimentological and micropalaeontological break from the deposits enclosing it the sedimentary characteristics of the horizon which consists of several distinct sub units vary greatly in both vertical and horizontal section detailed textural analysis through vertical sections of these sub units shows abrupt changes in particle size characteristics the highly variable nature of the horizon appears to be due to rapid variation in the hydrodynamic characteristics of the depositional event the lowermost section of the deposit appears to have been deposited from a highly turbulent water mass which was able to transport gravel sized clasts as well as gravel sized mud balls eroded from underlying material the water mass rapidly lost energy leading to the deposition of predominantly sand silt and clay particles sharp breaks in textural characteristics are likely to be due to changes in current direction caused by wave reflection or swash backwash interference the main sources of sand sized material within the deposit are the seaward barrier beach foredune system the tsunami deposit at boca do rio shares many of the sedimentary characteristics of tsunami deposits from other sites around the world

an extreme wave event in eastern yucatan mexico evidence of a palaeotsunami event during the mayan times the yucatan peninsula mexico has typically been considered a tectonically stable region without significant seismic activity in contrast the region is one that is regularly affected by hurricanes a detailed survey of ca 100 km of the eastern yucatan and cozumel coast identified the presence of ridges containing boulders measuring 1 m with up to three ridges at some locations the ridges reach five metres in height and their origin is associated with extreme wave event ewe activity previously modelled tsunami waves from known seismically active zones in the region muertos thrust belt and south caribbean deformed belt are not of sufficient at the yucatan peninsula to have produced the boulder ridges recorded in this study the occurrence of hurricanes in this region is more common but two of the most destructive hurricane gilbert 1988 and hurricane wilma 2005 produced coastal waves too small to have created the ridges recorded here in this paper a new tsunami model has been generated that indicates a tsunami event may have caused the ewe that resulted in the deposition of the boulders ridges

strong tsunami impact on the bay of aghios nikolaos and its environs nw greece during classical hellenistic times abstract this paper presents for the first time detailed geomorphological sedimentological geoarchaeological geophysical and geochemical evidence of a strong tsunami impact on the bay of aghios nikolaos and its environs nw greece during classical hellenistic times tsunamigenically dislocated beachrock slabs found on top of the santa maura beach ridge complex are closely interrelated to adjacent coarse grained washover fan deposits encountered in vibracores and detected by earth resistivity measurements based on detailed topographic surveys and geomorphometric investigations it was possible to localize areas of high intensity overflow underwater studies revealed that the central and northern parts of the former plaka beach ridge were completely destroyed by tsunami impact loose littoral deposits were flushed into the bay of aghios nikolaos and mega blocks of the underlying beachrock structure were dislocated landwards tsunami landfall occurred all along the eastern and northern shores of the bay where deposits partly weathered and associated to archaeological findings were found runup was estimated to minimum values between 2 3 m and 4 6 m a s l crosschecking the results of radiocarbon analyses with archaeological ages from five sites allowed to date the strong tsunami event to the time period between 395 cal bc and 247 cal bc due to the funnel like contour of the coastline the area is extremely sensitive to tsunami events of mid to high magnitude and high frequency

origin of cenozoic alkaline potassic volcanic rocks at konglongxiang lhasa terrane tibetan plateau products of partial melting of a mafic lower crustal source abstract it is generally believed that cenozoic potassic and ultrapotassic volcanic rocks of the tibetan plateau were generated by partial melting of enriched mantle this paper reports new data regarding the elemental and isotopic compositions of the konglongxiang volcanic rocks kvr k2o na2o 2 and low mgo contents in the middle western lhasa terrane tibetan plateau ar ar isotope dating of a sample from the kvr yields an age of 21 3 ma indicating that the kvr lavas erupted during the early miocene the kvr consists mainly of trachyte and rhyolite a comparison of the kvr with cenozoic potassic volcanic rocks of the tibetan plateau and the results of melting experiments involving k rich volcanic rocks as well as other k rich volcanic rocks from throughout the world reveals that the kvr trachytes originated from a mafic lower crust containing k rich minerals rather than from a mantle source the kvr rhyolites were probably derived from the middle upper crust based on age data compositional data and the regional tectonic setting we propose that the formation of the kvr and associated n s grabens was triggered by early miocene e w regional extension in the area of the southern tibetan plateau

tearing of the indian lithospheric slab beneath southern tibet revealed by sks wave splitting measurements a b s t r a c t shear wave birefringence is a direct diagnostic of seismic anisotropy it is often used to infer the northern limit of the underthrusting indian lithosphere based on the seismic anisotropy contrast between the indian and eurasian plates most studies have been made through several near north south trending passive source seismic experiments in southern tibet to investigate the geometry and the nature of the underthrusting indian lithosphere an east west trending seismic array consisting of 48 seismographs was operated in the central lhasa block from september 2009 to november 2010 splitting of sks waves was measured and verified with different methods along the profile the direction of fast wave polarization is about 60 in average with small fluctuations the delay time generally increases from east to west between 0 2 s and 1 0 s and its variation correlates spatially with north south oriented rifts in southern tibet the sks wave arrives 1 0 2 0 s later at stations in the eastern part of the profile than in the west the source of the anisotropy estimated by non overlapped parts of the fresnel zones at stations with different splitting parameters is concentrated above ca 195 km depth all the first order features suggest that the geometry of the underthrusting indian lithospheric slab in the himalayan tibetan collision zone beneath southern tibet is characterized by systematic lateral variations a slab tearing and or breakoff model of indian lithosphere with different subduction angles is likely a good candidate to explain the observations

holocene sedimentology and coastal geomorphology of zakynthos island ionian sea a history of a divided mediterranean island the island of zakynthos is one of the most seismically active areas in the mediterranean region because it is located very close to the convergent boundary between the african and eurasian plates its evolution during the holocene has been influenced by tectonic activity catastrophic events and relative sea level changes the scope of the present paper is to examine the holocene palaeoenvironmental changes of the coastal areas of zakynthos island using a multidisciplinary approach combining sedimentological and palaeontological data with 14c and osl dating from four cores of a maximum depth of 30 m the integrated results reveal that sea level and tectonic activity have brought significant modifications in the coastal geomorphic settings of the island during the past 10 000 yr b p the depositional environments and the palaeontological biofacies document four main geomorphological evolutionary stages of the island we identified fully marine and lagoonal deposits with marine influence before 4100 yr b p as well as brackish and freshwater limnic depositional environments around 4100 yr b p to present the interpretation of our data indicates that zakynthos island was separated into two main parts before the middle neolithic period around 7500 yr b p with vasilikos peninsula in the se being isolated from the main island the fact that zakynthos island was a divided mediterranean island for a significant period of time in its prehistory is of great importance to understand better the archaeological landscapes of zakynthos and the other ionian islands

tsunami deposits in holocene bay mud in southern kanto region pacific coast of central japan abstract tsunami have probably deposited sand sheets that are intercalated in holocene bay floor mud exposed on the boso and miura peninsulas facing the convergent boundary of the pacific philippine sea and eurasian plates we have identified seven sand sheets at four drowned valleys and correlated these by 137 radiocarbon dates of shells and wood the sheets consist of poorly sorted muddy sand and well sorted sand layers in fining upward sequences containing abundant transported shells rip up clasts and wood fragments the sheets erosionally overlie bioturbated bay floor mud that contains molluscan shells in life position most of the sheets are less than 20 cm thick and rarely more than 50 cm thick some molluscan shells are older in these layers than in underlying mud both landward and seaward paleocurrents are shown in a few cases by imbrication of shells and by low angle wedge shaped lamination at least five of the sand sheets contain molluscan fossils derived from rocky coasts or shore platforms although they intercalated in mud deposited within bays at depths of 10 15 m two other sand sheets are dominated by open seashore ostracode assemblages although they were deposited in the brackish inner bay and muddy central bay five of the layers may correlate with emergences recorded by nearby holocene marine terraces these correlations suggest that great earthquakes triggered the inferred tsunami the tsunami occurred at intervals of 300 2000 years beginning about 10 000 years ago

large boulder accumulations by extreme waves along the adriatic coast of southern apulia italy abstract the adriatic coast of southern apulia italy is marked by the presence of large boulder accumulations boulders are up to 8 t in weight and arranged either in small groups or rows composed of a few imbricated elements the lower surface of some of the boulders is covered by biogenic encrustation which suggests that they were possibly carved from the mid or sublittoral zone and that they capsized during their transport other boulders detached from the supratidal zone have their surface affected by tilted rock pools new horizontal solution pans are continually forming a detailed survey of a large boulder accumulation was carried out at torre santa sabina direct observations were also made concerning the carving out and transportation of one single boulder during the severe storms in that area on january 4th 2002 and on january 12th 2003 collated data from both the survey and the direct observations including some radiocarbon age determinations and hydrodynamic calculations suggest that the studied accumulation was due to the superimposed effects of one or two tsunami as well as of storm waves tsunami would be responsible for the detachment and transportation of the largest boulders while storm waves may have been responsible for the carving out and transportation of the newer smaller blocks and for moving once again the largest boulders it was in this way that a typical boulder accumulation was produced the collated data suggest that two tsunami may have recently struck the adriatic coast of southern apulia the first possibly took place on the dalmatian coast as a result of the earthquake on april 6 1667 which destroyed ragusa modern day dubrovnik the second tsunami would have accompanied the strong earthquake which took place in southern apulia on february 20 1743