remarkable bathymetric change in the nearshore zone by the 2004 indian ocean tsunami kirinda harbor sri lanka we investigated bathymetric data obtained at kirinda harbor sri lanka one month before and 2 and 11 months after the 2004 indian ocean tsunami our bathymetric surveyed data and numerical modeling results suggest that the first run up tsunami wave transported huge amounts of offshore sea bottom sediment and deposited it in a layer up to 4 m thick along the shoreface slope in some places this accreted sediment was not eroded by the backwash because of the particular arrangement of artificial structures and sand dunes especially the sedimentation process and the volume of the sediment transported by the run up waves can be examined where the influence of the backwash flow was very minor remarkable sedimentation attributable to the run up wave would have occurred mainly by the deposition of the sediment particles along the slope by the run up waves the slope was developed toward the stoss side rather than by the settlement of the sediment from the suspension load we estimated that considerable amounts of sediment were transported by the tsunami from the offshore sea bottom but most were deposited not on land but in the sea eleven months after the tsunami the harbor bathymetry had almost undergone complete reversion to its pre tsunami condition implying that the tsunami impact on permanent geomorphological landforms was limited at this harbor

preliminary paleoenvironmental analysis of permafrost deposits at batagaika megaslump yana uplands northeast siberia a megaslump at batagaika in northern yakutia exposes a remarkable stratigraphic sequence of permafrost deposits 50 80 m thick to determine their potential for answering key questions about quaternary environmental and climatic change in northeast siberia we carried out a reconnaissance study of their cryostratigraphy and paleoecology supported by four rangefinder 14c ages the sequence includes two ice complexes separated by a unit of fine sand containing narrow syngenetic ice wedges and multiple palaeosols overall the sequence developed as permafrost grew syngenetically through an eolian sand sheet aggrading on a hillslope wood remains occur in two forest beds each associated with a reddened weathering horizon the lower bed contains high amounts of larix pollen 20 plus small amounts of picea and pinus pumila and is attributed to interglacial conditions pollen from the overlying sequence is dominated by herbaceous taxa 70 80 attributed to an open tundra landscape during interstadial climatic conditions of three hypothetical age schemes considered we tentatively attribute much of the batagaika sequence to marine isotope stage mis 3 the upper and lower forest beds may represent a mid mis 3 optimum and mis 5 respectively although we cannot discount alternative attributions to mis 5 and 7

microfabric analysis of mn carbonate laminae deposition and mn sulfide formation in the gotland deep baltic sea the manganese carbonate deposits of the anoxic littorina sediments of the gotland deep have been commonly related to the periodic renewal of deep water by inflowing saline water from the north sea the use of scanning electron microscopy based techniques allows identification of small scale sedimentary and geochemical features associated with mn carbonate laminae which has significant implications for models of mn carbonate formation varves occurring in the littorina sequence contain up to four laminae that may be placed in a seasonal cycle and kutnahorite laminae occur within varves only as a winter early spring deposit this kutnahorite laminae seasonality is in agreement with the seasonal distribution of major baltic inflow events recorded in historical records and a direct causal link between inflows and kutnahorite deposition is implied benthic foraminifera tests are found to be heavily encrusted in kutnahorite implying that benthic recolonization during oxidation events occurs concurrently with kutnahorite formation the relatively common occurrence of small 50 to 100 m hexagonal mn sulfide pseudomorphs associated with 13 of kutnahorite laminae studied is reported in gotland deep sediments for the first time although mn sulfide crystals are not usually preserved in the sediment the discovery of mn sulfide pseudomorphs suggests that initial formation of mn sulfide in the gotland deep may occur much more commonly during the process of kutnahorite formation than previous reports of mn sulfide occurrence have implied

ostracod assemblages in late quaternary varved glaciomarine clay of the baltic sea yoldia stage in eastern middle sweden abstract four cored sites in eastern middle sweden have been analysed for their content of calcareous fossils the investigated sediments consist of late quaternary varved clay deposited during the baltic sea yoldia stage four regional palaeoecological units a d have been established unit a reflects ice proximal conditions unit b optimal conditions for the benthic fauna and unit c the termination of a saline phase in unit c oxygen deficiency might have occurred in the fourth unit d no fossils were found the fauna recorded is poor in taxa and indicates a weak marine influence the salinity was higher in the western part of the investigated area due to the proximity to the inlet of marine water the meltwater influx was high and the salinity probably fluctuated considerably the ostracod cytheromorpha macchesneyi brady and crosskey is reported for the first time in quaternary deposits from northwestern europe and indicates that a connection could have existed between the baltic and the white sea in late glacial times

historic and ancient tsunamis uncovered on the jalisco colima pacific coast the mexican subduction zone research on extreme wave events such as tsunamis using the geological record in areas of infrequent and or small magnitude earthquakes can aid in extending the long term history and recurrence intervals of large events this information is valuable for risk management and community preparedness in coastal areas here we investigate tsunami deposits on the jalisco coast of mexico that overlies the subducting rivera plate under the north american plate an area due for a large thrust earthquake and potential tsunami here we apply a full battery of rock magnetic analyses that also include a detailed ams study and other typically applied proxies in tsunami deposits research we present evidence to demonstrate that anomalous sand units with sharp basal contacts at la manzanilla tenacatita bay and el tecuan shore sites on the jalisco coast may be the products of tsunamis generated by known historical ms 8 2 earthquake of 3 june 1932 and other earlier tsunamigenic earthquakes a sandy unit with a sharp basal contact flame structures at the base rip up clasts at la manzanilla and four sand units with sharp basal contact overlying buried soils at el tecuan together with other proxies such as magnetic properties and others suggest tsunami deposits 210pb dating of sediments slightly above the upper sand layer indicate an age a d 1935 11 at el tecuan historical accounts of tsunami inundation at both sites provide further evidence that this is most probably the result of the 3 june 1932 tsunami hence this study may provide the first evidence of a tsunami triggered by this earthquake and also of three probable predecessors further evidence of at least three earlier tsunamis that occurred since the fifteenth century is also evident in the stratigraphy these events may correspond to events listed in historical archives namely the 1563 1816 and or the 1818 events

revealing the coastal event history of the andaman islands bay of bengal during the holocene using radiocarbon and osl dating earthquakes that trigger tsunamis are of great geological ecological and socio economic importance the knowledge of the recurrence interval of these events will give information about the hazard for a region coastal sediments on the andaman islands located in the eastern bay of bengal were investigated to find evidence for palaeotsunamis and palaeoearthquakes fieldwork was conducted on red skin island and north cinque island south of south andaman sediment material from event layers was dated by optically stimulated luminescence and radiocarbon dating method the results show evidence possibly for one earthquake at about 1 000 or 3 000 years before the present together with deposits from possible tsunamis and storms the complex pattern of co and post seismic uplift and subsidence of the andaman islands is reflected in the investigated sections and made it possible to reconstruct an event history for the last 3 000 years

typhoon haiyan overwash sediments from leyte gulf coastlines show local spatial variations with hybrid storm and tsunami signatures abstract marine inundation associated with the 5 to 8 m storm surge of typhoon haiyan in 2013 left overwash sediments inland on the coastal plains of the northwestern shores of leyte gulf philippines the haiyan overwash deposit provides a modern sedimentary record of storm surge deposition from a category 5 landfalling typhoon we studied overwash sediments at two locations that experienced similar storm surge conditions but represent contrasting sedimentological regimes namely a siliciclastic coast and a mixed siliciclastic carbonate coast the contrasting local geology is significantly reflected in the differences in sediment grain size composition and sorting at the two sites the haiyan overwash sediments are predominantly sand and silt and can be traced up to 1 6 km inland extending farther beyond the previously reported

shoreline displacement and human resource utilization in the southern baltic basin coastal zone during the early holocene new insights from a submerged mesolithic landscape in south eastern sweden along parts of the hano bay coast in south eastern sweden remains of a submerged landscape can be found down to depths of almost 25 m b s l the coastal landscape was formed during two periods of

a flying start then a slow slip the human tragedy caused by the sumatra andaman earthquake moment magnitude 9 3 on 26 december 2004 and its companion nias earthquake moment magnitude 8 7 on 28 march 2005 is difficult to comprehend these earthquakes the largest in 40 years have also left seismologists searching for the words and tools to describe the enormity of the geological processes involved four papers in this issue discuss aspects of a rupture process of surprising complexity the first such event to test the sensitivity and range of many new technologies a surprising feature of the earthquake is that after the initial rapid rupture subsequent slip of the plate interface occurred with decreasing speed toward the north

late weichselian and early holocene shore displacement in the central baltic sea abstract the glacial unloading and resulting isostatic land uplift have together with hydro isostasy eustatic rise of sea level and geoidal changes ruled the shore displacement of fennoscandia within the baltic basin periods of damming and shifts of outlet further complicated the shore displacement during the period studied ca 12 2 8 4 ka bp information on the baltic history was derived from shoreline observations and studies on sediment cores from lakes formerly directly affected by the baltic these cores were analyzed with respect to pollen diatoms and lithology to determine sequences of baltic sediments and dated by a combination of radiocarbon dates and biostratigraphy the studied areas of southeastern sweden mainly central gotland and the oskarshamn area eastern smaland display a similar course of shore displacement the late weichselian period shows a regression of a slightly decreasing rate between ca 12 2 and 10 3 ka bp then followed a fast drop 25 m of the baltic s water level the final drainage of the baltic ice lake during the next ca 700 years the yoldia stage a regression of ca 17 m occurred this period is mainly characterized by freshwater diatoms in the baltic but at ca 10 ka bp there is evidence of a shortlasting 100 150 year period with brackish water the ancylus transgression of ca 11 m began ca 9 6 ka bp and culminated ca 9 3 ka bp it was followed by a fast regression of 8 10 m thereafter the rate of regression decreased shoreline gradients showed that the fastest shoreline tilting occurred around 10 ka bp thus ca 2 ka after deglaciation

early holocene deglaciation chronology in vastergotland and narke southern sweden biostratigraphy clay varve 14c and calendar year chronology this thesis outlines an event stratigraphy for the last glacial holocene transition in eastern middle sweden events are short lived occurrences that have left traces in the geological record and w

comment on reconstructing tsunami run up from the characteristics of tsunami deposits on the thai andaman coast by srisutam and wagner 2010 abstract in this short comment we address several approximations and assumptions in a model of tsunami reconstruction from the characteristics of tsunami deposits presented by soulsby et al 2007 in a conference and adapted by srisutam and wagner 2010 to the 2004 tsunami deposits in thailand

new insights into the weichselian environment and climate of the east siberian arctic derived from fossil insects plants and mammals multidisciplinary study of a key section on the laptev sea coast bykovsky peninsula east lena delta in 1998 2001 provides the most complete record of middle and late weichselian environments in the east siberian arctic the 40 m high mamontovy khayata cliff is a typical ice complex section built of icy silts with a network of large syngenetic polygonal ice wedges and is richly fossiliferous in combination with pollen plant macrofossil and mammal fossils a sequence of ca 70 insect samples provides a new interpretation of the environment and climate of the area between ca 50 and 12 ka the large number of radiocarbon dates from the section together with an extensive 14c database on mammal bones allows chronological correlation of the various proxies the bykovsky record shows how climate change and the last glacial maximum in particular affected terrestrial organisms such as insects and large grazing mammals both during the presumed karginsky interstadial mis 3 and the sartanian glacial mis 2 the vegetation remained a mosaic arctic grassland with relatively high diversity of grasses and herbs and dominance of xeric habitats the tundra steppe type this biome was supported by a constantly very continental climate caused by low sea level and enormous extension of shelf land variations within the broad pattern were caused mainly by fluctuations in summer temperature related to global trends but overprinted by the effect of continentality no major changes in humidity were observed nor were advances of modern type forest or forest tundra recorded suggesting a major revision of the karginsky interstadial paradigm the changing subtypes of the tundra steppe environment were persistently favourable for mammalian grazers which inhabited the shelf lowlands throughout the studied period mammal population numbers were lowered during the lgm especially toward its end and then flourished in a short but impressive peak in the latest weichselian just before the collapse of the tundra steppe biome throughout mis 3 and mis 2 the climate remained very favourable for the aggradation of permafrost no events of regional permafrost degradation were observed in the continuous bykovsky sequence until the very end of the pleistocene

sheltered coastal environments as archives of paleo tsunami deposits observations from the 2004 indian ocean tsunami the 2004 earthquake left several traces of coseismic land deformation and tsunami deposits both on the islands along the plate boundary and distant shores of the indian ocean rim countries researchers are now exploring these sites to develop a chronology of past events where the coastal regions are also inundated by storm surges there is an additional challenge to discriminate between the deposits formed by these two processes paleo tsunami research relies largely on finding deposits where preservation potential is high and storm surge origin can be excluded during the past decade of our work along the andaman and nicobar islands and the east coast of india we have observed that the 2004 tsunami deposits are best preserved in lagoons inland streams and also on elevated terraces chronological evidence for older events obtained from such sites is better correlated with those from thailand sri lanka and indonesia reiterating their usefulness in tsunami geology studies c 2014 elsevier ltd all rights reserved

numerical assessment of bathymetric changes caused by the 2004 indian ocean tsunami at kirinda fishery harbor sri lanka abstract thus far various numerical models have been developed and improved to aid understanding of the sediment transport process due to tsunamis however the applicability of these models for the field scale bathymetric change remains a major issue due to the scarcity of measured bathymetric data immediately before and after tsunamis this study focuses on assessing the applicability of the sediment transport model by comparing the model results with measured bathymetry data obtained one month before and two months after the 2004 indian ocean tsunami at kirinda fishery harbor sri lanka obtained model results were compared with measured data along four different transects in particular similar to the measured data the model reproduced the bed level change at the harbor mouth well although it shows some discrepancy on bathymetric change along the shoreline which is directly affected by littoral drift therefore it is noted that the divergence of reproducing the local bathymetry change is due to the normal wind wave effect on measured data and the model limitations hence we included the wind wave effect in modeled data and the discrepancy between measured and modeled data was reduced furthermore the modeled bed level change indicates a dynamic behavior in terms of the net variation during the tsunami flow such that deposition dominates in the inflow and erosion dominates in the backflow both bed level variation and the suspended load concentration reveal that the large amount of eroded sediment attributable to tsunami waves was in suspended form and was deposited in the nearshore area after the water fluctuation had abated the model results further indicate that eroded sediment at the initial depth deeper than 11 m might be brought by the incoming tsunami waves and deposited in the nearshore area where the depth is shallower than 7 m

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

relationship between the maximum extent of tsunami sand and the inundation limit of the 2011 tohoku oki tsunami on the sendai plain japan abstract this paper focuses on the relationship between the maximum extent of sandy tsunami deposits and inundation distance of the 2011 tohoku oki tsunami inundation limits of the tohoku oki tsunami were assessed over seven shore normal transects along the sendai coastal plain inundation distances were found to range from 0 6 to 4 0 km at the maximum extent of the tsunami deposit the sand unit ranged in thicknesses from 0 1 to 4 0 cm the maximum limit of the 0 5 cm thick sand layer extended to over 90 of the inundation distance where the inundation distance was less than 2 5 km this observation is consistent with previous studies that examined characteristics of recent tsunami events that had inundation distances of at least 2 km the maximum limit of the 0 5 cm thick sand layer extended to 3 km 57 76 of the inundation distance where the inundation distance was more than 2 5 km our results are important for estimating paleo tsunami inundation distances based on the landward extent of sand deposits and valuable for the assessment of future tsunami risks in other coastal areas in the world which have been devastated by huge tsunamis in the past

coastal stratigraphies of eastern bonaire netherlands antilles new insights into the palaeo tsunami history of the southern caribbean abstract a sediment record of three alluvial sites along the east and northeast oriented shore of bonaire netherlands antilles provides evidence for the recurrence of several extraordinary wave impacts during the holocene the interpretation of onshore high energy wave deposits is controversially discussed in recent sedimentary research however it represents a powerful tool to evaluate the hazard of tsunami and severe storms where historical documentation is short and or fragmentary a facies model was established based on sedimentary and geochemical characteristics as well as the assemblage and state of preservation of shells and shell fragments radiocarbon data and the comparison of the facies model with both recent local hurricane deposits and global tsunami signature types point to the occurrence of three major wave events around 3300 2000 1700 and shortly before 500 bp since i the stratigraphically correlated sand layers fulfill several sedimentary characteristics commonly associated with tsunamis and ii modern strong hurricanes left only little or even no sediment in the study areas they were interpreted as tsunamigenic however surges largely exceeding the energy of those accompanying modern hurricanes in the southern caribbean cannot entirely be ruled out the results are partially consistent with existing chronologies for holocene extreme wave events deduced from supralittoral coarse clast deposits on aruba bonaire and curacao as well as overwash sediments from cayo sal venezuela

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

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

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

deglaciation shore displacement and early holocene vegetation history in eastern middle sweden the sedimentary record at lake vibysjo lake basin is situated close to the narke strait where the main water exchange occurred between the vanern basin and baltic basin during the middle and late phases of the yoldia sea stage of the baltic sea c 10 000 9500 14c years bp the area was deglaciated in a glaciomarine environment as reflected by the occurrence of benthic calcareous fossils foraminifera ostracods and the mollusc portlandia arctica gray in the lower most clay units the estimated date of deglaciation 10 440 clay varve years bp suggests that a saline bottom water current entered the baltic basin shortly after the high areas south of lake vibysjon became free of ice the brackish water fauna occurs during a regional betula empetrum hippophae pollen zone which in southern sweden is correlated with the early preboreal the isolation of the lake vibysjon basin is dated to 8100 14c years bp and occurred during the last part of the ancylus lake stage based on investigations of other bas

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

holocene history of the baltic sea as a background for assessing records of human impact in the sediments of the gotland basin sediment cores from the gotland basin were studied for their siliceous microfossil assemblages and organic carbon content to compare recent environmental changes in the baltic sea with its natural

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

vegetation and climate history in the laptev sea region arctic siberia during late quaternary inferred from pollen records abstract paleoenvironmental records from a number of permafrost sections and lacustrine cores from the laptev sea region dated by several methods 14 c ams tl irsl osl and 230 th u were analyzed for pollen and palynomorphs the records reveal the environmental history for the last ca 200 kyr for interglacial pollen spectra quantitative temperature values were estimated using the best modern analogue method sparse grass sedge vegetation indicating arctic desert environmental conditions existed prior to 200 kyr ago dense wet grass sedge tundra habitats dominated during an interstadial ca 200 190 kyr ago reflecting warmer and wetter summers than before sparser vegetation communities point to much more severe stadial conditions ca 190 130 kyr ago open grass and artemisia communities with shrub stands alnus fruticosa salix betula nana in more protected and moister places characterized the beginning of the last interglacial indicate climate conditions similar to present shrub tundra alnus fruticosa and betula nana dominated during the middle eemian climatic optimum when summer temperatures were 4 5 c higher than today early weichselian sparse grass sedge dominated vegetation indicates climate conditions colder and dryer than in the previous interval middle weichselian interstadial records indicate moister and warmer climate conditions for example in the interval 40 32 kyr bp salix was present within dense grass sedge dominated vegetation sedge grass artemisia communities indicate that climate became cooler and drier after 30 kyr bp and cold dry conditions characterized the late weichselian ca 26 16 kyr bp when grass dominated communities with caryophyllaceae asteraceae cichoriaceae selaginella rupestris were present from 16 to 12 kyr bp grass sedge communities with caryophyllaceae asteraceae and cichoriaceae indicate climate was significantly warmer and moister than during the previous interval the presence of salix and betula reflect temperatures about 4 c higher than present at about 12 11 kyr bp during the allerod interval but shrubs were absent in the younger dryas interval pointing to a deterioration of climate conditions alnus fruticosa betula nana poaceae and cyperaceae dominate early holocene spectra reconstructed absolute temperature values were substantially warmer than present up to 12 c shrubs gradually disappeared from coastal areas after 7 6 kyr bp when vegetation cover became similar to modern a comparison of proxy based paleoenvironmental reconstructions with the simulations performed by an earth system model of intermediate complexity climber 2 show good accordance between the regional paleodata and model simulations especially for the warmer intervals

the great sumatra andaman earthquake of 26 december 2004 the two largest earthquakes of the past 40 years ruptured a 1600 kilometer long portion of the fault boundary between the indo australian and southeastern eurasian plates on 26 december 2004 seismic moment magnitude mw 9 1 to 9 3 and 28 march 2005 mw 8 6 the first event generated a tsunami that caused more than 283 000 deaths fault slip of up to 15 meters occurred near banda aceh sumatra but to the north along the nicobar and andaman islands rapid slip was much smaller tsunami and geodetic observations indicate that additional slow slip occurred in the north over a time scale of 50 minutes or longer

local variation of inundation sedimentary characteristics and mineral assemblages of the 2011 tohoku oki tsunami on the misawa coast aomori japan abstract the 2011 tohoku oki tsunami caused severe damage to the coastal regions of eastern japan and left a sediment veneer over affected areas we discuss differences in depositional characteristics of the 2011 tohoku oki tsunami from the viewpoint of the sediment source coastal topography and flow height the study area on the misawa coast northern tohoku includes a 20 km long coastline with sandy beaches coastal dunes and a gently sloping lowland this landscape assemblage provides an opportunity to examine the effects of topography on the characteristics of the tsunami deposit during field surveys conducted from april 10 to may 2 2011 we described the thickness facies and structure of the tsunami deposit we also collected sand samples at approximately 20 m intervals along 13 shore perpendicular transects extending up to 550 m inland for grain size and mineral assemblage analysis the tsunami flow height was estimated by measuring the elevation of debris found in trees broken tree limbs or water marks on buildings the nature of the coastal lowland affected the flow height and inundation distance in the southern part of the study area where there is a narrow 100 m wide low lying coastal strip the run up height reached 10 m on the landward terrace slopes to the north the maximum inundation reached 550 m with a run up height of 3 2 m on the wider low lying coastal topography the average flow height was 4 5 m the tsunami eroded coastal dunes and formed small scarps along the coast immediately landward of the coastal dunes the tsunami deposit was more than 20 cm thick but thinned markedly inland from this point close to the dunes the deposit was composed largely of medium sand 1 2 with planar and parallel bedding but with no apparent upward fining or coarsening the grain size was similar to that of the coastal dune and we infer that the dunes were the local source material for the tsunami deposit at this point the mineral assemblage of the tsunami deposit was dominated by orthopyroxene and clinopyroxene and was also similar to the dune and beach sand at sites more than half the inundation distance inland the thinner tsunami deposit consisted mainly of fine sand 2 375 with some upward fining the difference in grain size and sedimentary characteristics was probably caused by differences in sediment transportation and depositional processes we infer that the well sorted finer sediments were deposited out of suspension whereas the relatively coarse sands were laid down from traction flows the depositional characteristics of the 2011 tohoku oki tsunami deposit appeared to have been affected mainly by the coastal topography and the extent of erosion at any one point as opposed to flow height

examination of relation with tsunami behavior reconstructed from on site sequence photographs topography and sedimentary deposits from the 2011 tohoku oki tsunami on the kamikita plain japan abstract this report presents an examination of tsunami behavior for the misawa coast of northeastern japan based on interpretations of sequential digital photographs of the 2011 tohoku oki tsunami spatial distribution of tsunami deposits and topographical conditions reconstructed using the digital elevation model dem in the study area run up flow and then backwash flow occurred only once run up flow reached maximum inundation height several minutes after tsunami flooding started topographic features such as terraces dissected valleys coastal lowlands and artificial seawall constrained the tsunami flow the sandy tsunami deposit distribution is limited to several hundred meters from the shoreline deposits show inland thinning and fining they also indicate thinning and fining in the direction of higher surfaces thick deposits which are distributed locally in the basin area between the beach ridge and the seawall exhibited multiple layers of inverse and normal grading formed by repeated acceleration and deceleration for several minutes during the run up flow in the area with concentrated backwash flow after the tsunami struck the sedimentation for tsunami deposits was affected not only by the run up flow but also by the backwash flow

potential predecessors of the 2004 indian ocean tsunami sedimentary evidence of extreme wave events at ban bang sak sw thailand abstract where historical records are short and or fragmentary geological evidence is an important tool to reconstruct the recurrence rate of extreme wave events tsunamis and or storms this is particularly true for those coastal zones around the indian ocean where predecessors of similar magnitude as the 2004 indian ocean tsunami iot have not been reported by written sources in this context the sedimentary record of the holocene coastal plain of ban bang sak phang nga province thailand provides evidence of multiple prehistoric coastal flooding events in the form of allochthonous sand beds which were radiocarbon dated to 700 500 1350 1180 and younger than 2000 cal bp the layers were assigned to high energy events of marine origin which could be either tsunamis or tropical storms by means of granulometry geochemistry vertical structure and macrofossil content although no landfall of a strong storm has occurred in the last 150 years of meteorological data recording cyclones cannot be ruled out for the last centuries and millennia however discrimination between tsunami and storm origin was mainly based on the comparison of the palaeoevent beds with the local deposit of the iot which revealed similar characteristics in regard to spatial extend and sediment properties furthermore the youngest palaeoevent correlates with contemporaneous deposits from thailand and more distant coasts hence we relate it to a basin wide tsunami which took place 700 500 years ago for the sediments of older extreme events deposited between 2000 and 1180 cal bp we found no unambiguous counterparts at other sites nevertheless at least for now they are treated as tsunami candidates

erosion deposition and landscape change on the sendai coastal plain japan resulting from the march 11 2011 tohoku oki tsunami case studies of recent tsunami impacts have proven to be extremely useful in understanding the geologic processes involved during inundation and return flow and refining the criteria used to identify paleotsunami deposits in the geologic record here we report on erosion deposition and associated landscape change resulting from the march 11 2011 tohoku oki tsunami along a nearly 4 5 km shore normal transect on the coastal plain near sendai japan the study area on the broad low relief prograding coastal sendai plain comprised a sand beach backed by 3 m high sand dunes and a forest a wetland the teizan canal agricultural rice fields buildings and roads field observations focused on measurements of tsunami flow characteristics height and direction mapping of erosion features and assessing sediment deposition based on shallow trenches at 50 100 m spacing recorded tsunami inundation heights reached up to about 11 m above mean sea level within the first 500 m from the shoreline and then ranged between 3 and 5 m for the next 2 km gradually decreasing to about 3 m close to the inundation limit the tsunami deposit generally thinned landward from an average maximum 30 cm thick sand deposit in the coastal forest to a thin mud drape several mm thick near the inundation limit a discontinuous sand dominated sheet was prevalent to about 2800 m from the shoreline where mud content then gradually increased further landward eventually resulting in a mud dominated deposit ranging from 3 5 cm to a few mm thickness the overall thinning and fining of the deposit was often interrupted by localized features that led to complex sedimentological relationships over short distances satellite imagery taken on 14 march 2011 3 days after the tohoku oki tsunami shows prominent foreshore incisions with 100 s meters spacing alongshore a foredune ridge that underwent severe erosion and development of a prominent shore parallel elongated scour depression our field survey in early may 2011 revealed that the foreshore recovered quickly with rapid post tsunami sediment deposition from incident waves whereas the dune ridge complex had undergone only minor re working from eolian processes

proxy mineral magnetic and elemental analyses for 2004 tsunami impact deposit along the muttukadu backwater east coast of india scope of the palaeotsunami studies abstract following the line of approach enumerated in the tsunami toolkit of chague goff et al 2011 expanding the proxy toolkit to help identify past events lessons from the 2004 indian ocean tsunami and the 2009 south pacific tsunami earth sci rev 107 1 2 107 122 measurements of elemental and mineral magnetic properties coupled with textural parameters have been used to evaluate the 2004 indian ocean tsunami iot induced sediments on the muttukadu backwaters east coast of india to investigate the sediment provenance specific fe mn and pb elemental concentrations were measured in surface sediments and compared with the previously published pre tsunami database of backwater inner continental shelf sediments we found the enrichment of fe and pb against depletion of mn concentration in present tsunami sediments as compared with pre tsunami muttukadu sediments reflecting the variation of the sediment source area however the present data of fe and pb enrichment and mn depletion correlates well with continental shelf sediments hinting at sedimentary routes processes of erosion and wave propagation the studied tsunami deposits are characterized by dominant 40 85 coarse sand fractions and higher proportion of detrital low and high coercivity fe ti oxides such as magnetite titanomagnetite and hematite reflected by magnetic concentration magnetic susceptibility anhysteretic remanent magnetization arm and coercivity dependent parameters soft isothermal remanent magnetization soft irm hard irm magnetomineralogical s ratio and saturation irm sirm so it can be shown that the random spatial variability and the inverse relationship between magnetic concentration arm and sirm parameters and grain size arm sirm and arm sirm ratios as diagnostic criteria for the tsunami impacted the distribution of magnetic parameters in coastal backwater environments contrasting mineral magnetic and geochemical properties together with more sand mean 65 when compared with silt mean 25 content in tsunami sediments indicates that the area was affected by high energy tsunami waves the study validates environmental magnetism as a proxy which is fast and robust for identifying the tsunami or palaeotsunami deposits

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

ground penetrating radar examination of thin tsunami beds a case study from phra thong island thailand coastal overwash deposits from tsunamis and storms have been identified and characterised from many coastal environments to date these investigations have utilised ad hoc time energy and cost intensive invasive techniques such as pits and trenches or taking core samples here we present the application of high frequency ground penetrating radar gpr to identify and characterise the 2004 indian ocean tsunami iot and palaeotsunami deposits from phra thong island thailand this site is one of the most intensively studied palaeotsunami sites globally and preserves a series of late holocene stacked sandy tsunami deposits within an organic muddy low energy backbeach environment using 100 500 and 1000 mhz gpr antennas 29 reflection profiles were collected from two swales x and y inland of the modern beach and two common mid point cmp profiles using the 200 mhz antennas were collected from swale y detailed examination of the cmps allowed accurate velocity estimates to be applied to each profile the reflection profiles included across swale profiles and a high resolution grid in swale x and were collected to investigate the feasibility of gpr to image the palaeotsunami deposits and two profiles from swale y where the tsunami deposits are poorly known the 500 mhz antennas provided the best stratigraphic resolution which was independently validated from the stratigraphy and sedimentology recovered from 17 auger cores collected along the profiles it is clear from the augers and gpr data that the different dielectric properties of the individual layers allow the identification of the iot and earlier tsunami deposits on phra thong island although applied in a coastal setting here this technique can be applied to other environments where thin sand beds are preserved in order to prioritise sites for detailed examination

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

vented sediments and tsunami deposits in the puget lowland washington differentiating sedimentary processes the sandy deposits produced by tsunamis and liquefaction share many sedimentary features and distinctions between the two are important in seismically active coastal zones both types of deposits are present in the wetlands bordering puget sound where one or more earthquakes about 1100 years ago caused both tsunami flooding and sediment venting this co occurrence allows an examination of the resulting deposits and a comparison with tsunami and liquefaction features of modern events vented sediments occur at four of five wetland field localities and tsunami deposits at two in comparison with tsunami deposits vented sediments in this study and from other studies tend to be thicker although they can be thin vented sediments also have more variable thickness at both outcrop and map scale are associated with injected dykes and contain clasts derived from underlying deposits further vented sediments tend to contain a greater variety of sedimentary structures and these structures vary laterally over metres tsunami deposits compared with vented sediments are commonly thinner fine and thin landward more consistently have more uniform thickness on outcrop and map scales and have the potential of containing coarser clasts up to boulders for both tsunami deposits and vented sediments the availability and grain size of source material condition the characteristics of the deposit in the cases presented in this paper both foraminifera and diatom assemblages within tsunami deposits and vented sediments consisted of brackish and marine species and no distinction between processes could be made based on microfossils in summary this study indicates a need for more careful analysis and mapping of coastal sediments associated with earthquakes to avoid misidentification of processes and misevaluation of hazards

problems of the last interglacial in arctic siberia abstract the basic problem in reconstructing the last interglacial in the siberian arctic is to recognize correlative deposits in the quaternary sequence assignment of any particular warm event to the last interglacial is usually based on various indirect criteria there is no one independent criterion that could distinguish the last interglacial from earlier or later warm periods potentially the most rapidly evolved mammal lineage of collared lemmings could be helpful for dating the last interglacial in the arctic but there are still some problems to be solved another important problem is climatic interpretation of warm events presumably referred to the last interglacial most commonly such reconstructions are based on the concept of northward shift of modern like plant communities but some features of pollen spectra and insect faunas suggest a special character of communities existed during the warm events in the arctic they do not seem to be exact analogues of modern communities and a non uniformitarian approach is necessary for their climatic interpretation survival of tundra steppe communities and grazing mammals through the last interglacial climatic change suggests that it was not so destructive for the arctic ecosystems as the pleistocene holocene environment restructuring

erosion and sedimentation in kalpakkam n tamil nadu india from the 26th december 2004 tsunami abstract laterally extensive sand sheets deposited by the 26th december 2004 asian tsunami provide a valuable modern analogue for comparison with wash over deposits of unknown origin in many places on the east coast of india distinct deposits of marine sand drape the landscape and overlie the muddy soils of the coastal plain this paper discusses detailed measurements of coastal topography tsunami flow height and deposit thickness made at kalpakkam india five transects were examined in detail to assess the sedimentology and spatial distribution of the tsunami deposit near the mean water line the tsunami eroded approximately 10 25 cm of sand from the beach and berm at kalpakkam the sand sheet deposited by the tsunami begins 25 m from the shore extending 420 m inland where it becomes thin and patchy approximately 30 m from the limit of inundation in some cases the deposit consists of 2 to 4 normally graded units with coarse sand near the base and fine sand at the top a characteristic observed in many tsunami deposits worldwide in many places the deposits also contain numerous thin laminated units a characteristic usually associated with storm over wash the presence of the laminated beds is indicative of the complexity of tsunami sedimentation on the coast such observations are essential to the formation of definitive facies models for palaeo overwash studies that are capable of distinguishing between sediments deposited by storms or tsunami

tsunami history over the past 2000 years on the sanriku coast japan determined using gravel deposits to estimate tsunami inundation behavior abstract at numanohama marsh on the rocky sanriku coast in northeast japan we identified 17 sand layers with sedimentary structures characteristic of event deposits i e a sharp erosional contact with the underlying unit a normal and or inverse grading structure parallel cross lamination mud clasts and or a thin mud layer abundant marine nannofossils coccoliths and the small catchment area in the narrow valley suggest that these event layers were likely formed by inundations during tsunamis or storms among the 17 sand layers nine contained gravels derived from the beach riverbed or slope areas six event layers contained all three of these gravels suggesting a strong inflow current that transported round pebbles from the beach erosion of wall rock in the valley during the inflow and outflow phases and a backwash current that caused sub angular riverbed gravel to accumulate in lowland areas these six layers were traced up to 490 m inland from the coastline present elevation 7 m above mean sea level and were several cm thick at almost every survey point we concluded that these six event layers are tsunami deposits and dating results revealed that they correlate with the 2011 tohoku oki earthquake the 1933 and 1896 sanriku oki earthquakes any of the 1763 aomori oki 1793 miyagi oki and 1856 aomori oki earthquakes the 1611 tohoku oki earthquake and the 869 tohoku oki jogan earthquake in addition changes in the sedimentary environment inferred from diatom assemblages were well correlated with the deposition of three of the event layers two historical earthquakes the 1454 and 1611 tohoku oki earthquakes have been previously suggested as being the immediate predecessors of the 2011 tohoku oki earthquake and our dating results favor the 1611 earthquake although the source region of the 869 tohoku oki jogan earthquake has been estimated to have been off the fukushima and miyagi prefectures our results suggest that the source region extended further north along the japan trench

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

an event stratigraphy for the last glacial holocene transition in eastern middle sweden results from investigations of varved clay and terrestrial sequences this paper presents an event stratigraphy for the last glacial holocene transition in eastern middle sweden the event stratigraphy for eastern middle sweden comprises ten events and covers the tim

andrei sher and quaternary science abstract andrei sher 1939 2008 was a key individual in beringian studies who made substantial and original contributions but also importantly built bridges between western and eastern beringian scientists spanning some five decades of research he is perhaps best known as a quaternary palaeontologist specializing in large mammals and mammoths in particular but his field of his scientific research was much broader encompassing quaternary geology stratigraphy geocryology and paleoenvironmental reconstructions he worked mainly in siberia in the kolyma and indigirka lowlands and chukotka but also completed fieldwork in alaska and yukon through joint projects with american and canadian scientists andrei was an active scientist until the last days of his life he was involved in many different research projects ranging from mammoth evolution fossil insects and environmental changes and ancient dna without andrei s connections between researchers many unique discoveries would likely be unknown

marine conditions in central sweden during the early preboreal as inferred from a stable oxygen isotope gradient the marine benthic fauna and the 18 oc of foraminifers and ostracods from six sites situated on a west east transect through central sweden have been analysed in order to estimate the palaeosalinity and palaeocirculation in this shallow marine environment the measurements have been undertaken on material from the early preboreal when the baltic basin was in contact with the north sea through straits in central sweden the 18 oc values have a more negative value towards the east indicating decreasing salinity this was the result of limited possibilities for marine water to penetrate into the baltic basin and the mixing with freshwater from the melting fennoscandian ice sheet four water masses existed in the area a surface layer of freshwater marine water from the north sea brackish marine intermediate water on the swedish west coast and brackish yoldia sea water in the baltic basin the chronology is based on radiocarbon dates of marine fossils and at one site on the occurrence of the vedde ash 10 400 10 300 14 c yr bp this is the first record from marine settings in sweden copyright 2001 john wiley sons ltd journal of quaternary science

a submerged mesolithic lagoonal landscape in the baltic sea south eastern sweden early holocene environmental reconstruction and shore level displacement based on a multiproxy approach abstract remains of a submerged landscape around the mouth of a small river are preserved off the baltic sea coast at havang in south eastern sweden organic rich sediment ridges with abundant wood remains and archaeological artefacts extend 3 km from the modern coast to depths of at least 20 m below the present sea level this exceptionally well preserved material gives evidence of a lagoonal environment surrounded by a pine dominated forest which was inhabited by mesolithic humans during two low stand phases of the baltic basin from the yoldia sea stage to the initial littorina sea stage c 11 700 8000 cal bp as part of ongoing efforts to reconstruct the local landscape development and to refine the shore level displacement history during the early holocene a 3 m sediment sequence was collected at 8 m b s l and dated by radiocarbon analysis a multi proxy stratigraphic approach was applied to the sediment record including pollen diatom organic and inorganic elemental analyses this stratigraphic dataset is explored in the context of detailed bathymetry of the area based on multibeam echo sounding and surveillance and sampling of artefacts by divers the investigated sediment sequence reflects a stable highly productive lagoonal environment with an unusually high sediment accumulation rate at c 9100 8600 cal bp the uppermost 1 m part of the sequence represents a destabilized depositional environment interpreted as reflecting an increased influence of brackish water due to the approaching coastline during the littorina transgression the shore level displacement in the area is characterized by rapid water level fluctuations following a regression to around 22 m b s l during the yoldia sea stage the ancylus transgression reached a maximum of 2 m b s l followed by a second regression to a low stand at 12 m b s l during the initial littorina sea stage several unprecedented archaeological findings made in the study area are presented and discussed including stationary fishing constructions dated to c 9100 8400 cal bp these constructions the oldest known in northern europe indicate extensive riverine and lagoonal fishing previously not recorded during the mesolithic in sweden furthermore bones and antlers of red deer with slaughter marks and a unique pick axe made of elk antler provide evidence of human exploitation of terrestrial resources the havang site shows the strong potential of submerged landscapes as palaeoecological source materials and demonstrates the importance of resources at coastal settings near river mouths for mesolithic communities

environmental conditions inferred from multi element concentrations in sediments off cauvery delta southeast india we present multi element concentrations in the surface sediments from the offshore of cauvery delta of southeast india to evaluate the impact of coastal pollution on the geochemical behaviour of surface deposits for this study 16 surface sediment samples were collected from the offshore of cauvery delta of southeast india and were analysed using traditional xrf for various major sio2 al2o3 mgo fe2o3 mno na2o k2o cao p2o5 tio2 and trace elements rb sr ba y zr nb v cr co ni cu zn th pb after powdering it to astm 230 63 m the main objectives of this study were to understand the geochemical behaviour of the coastal surface sediments and its performance and relation with the pollution indices and statistical analysis to meet out the objective pollution indices such as enrichment factor ef contamination factor cf and geoaccumulation index i geo were calculated and statistical analyses were performed to understand the relationship between the geochemical parameters both ef and i geo show the enrichment of cu cr and zr whereas cf shows enrichment of cu and cr statistical analyses exhibit poor correlation between these elements and fine fraction indicating the insignificant role played by both grain size and organic matter strong positive association between cu and zn with caco3 exhibits the role of carbonates in precipitating these metals from the overlying water column possibly related to agricultural pollution distribution and association of other elements suggest the influence of mineralogy in geochemical composition of surface sediments based on this study we suggest that environmental indices alone should not be considered for evaluating environmental conditions and a prior geogenic characterisation of the sediments is necessary

the last interglaciation in northeast siberia abstract alluvial fluvial and organic deposits of the last interglaciation are exposed along numerous river terraces in northeast siberia although chronological control is often poor the paleobotanical data suggest range extensions of up to 1000 km for the primary tree species these data also indicate that boreal communities of the last interglaciation were similar to modern ones in composition but their distributions were displaced significantly to the north northwest inferences about climate of this period suggest that mean july temperatures were warmer by 4 to 8 c and seasonal precipitation was slightly greater mean january temperatures may have been severely cooler than today up to 12 c along the arctic coast but similar or slightly warmer than present in other areas the direction and magnitude of change in july temperatures agree with atmospheric general circulation models but the 126 000 year b p model results also suggest trends opposite to the paleobotanical data with simulated cooler winter temperatures and drier conditions than present during the climatic optimum

geomorphological effects of tsunami run up and backwash abstract geomorphological processes associated with tsunami run up and backwash are highly complex to date most studies have considered the sedimentology of palaeo tsunamis while almost no detailed studies have been undertaken in areas known to have been affected by tsunamis in recent times research on contemporary tsunamis show that coastal landscapes may be greatly altered not only by direct tsunami run up orthogonal to the shoreline but also by episodes of vigorous backwash and by water flow sub parallel to the coastline the combined effect of these processes produces hitherto unrecognised coastal landforms that are dominated by the effects of high magnitude erosion and deposition deposition of large boulders is also associated with severe tsunamis while in adjacent areas run up processes often result in the deposition of continuous and discontinuous sediment sheets in many instances the upper limit of sediment deposition lies well below the upper limit of wave run up which is frequently marked by a well defined zone of stripped vegetation and soil the processes described have considerable implications for models of coastal evolution it may even be the case that the evolution of particular stretches of coastline are dominated by such high magnitude low frequency events

styles of early diagenesis and the preservation potential of onshore tsunami deposits a re survey of isla mocha central chile 2 years after the february 27 2010 maule tsunami abstract the style of early diagenesis and preservation of onshore tsunami deposits are poorly constrained only tsunami surveys and subsequent re surveys can fill this information gap here we present the results of a first re survey in 2012 on isla mocha following the original survey in 2010 in the wake of the february 27 2010 maule earthquake and tsunami in central chile as a result of this tsunami a large number of boulders consisting of clay rich fine sandstones representing the miocene age bedrock of the island had been transferred from the tidal to shallow subtidal zone onto the coastal plain coarse clastic sediment mixtures of pebbles granules and sand entrained at coastal plain terraces and transported up to the maximum runup position c 600 m from the coast by the inflow had been left behind as extensive backflow blankets on the lower coastal plain in 2012 vegetation had covered the 2010 tsunami deposits sediment beyond 200 m from the coast had been removed by a combination of surface processes and grazing cattle grain size distributions of the preserved sediment show an increase of the sand fraction at the expense of the coarser grain sizes boulders show patterns resembling mud cracks on the surface and evidence of disintegration into smaller fragments and sand veneers of dried algae documenting the derivation of the boulders from the tidal zones had flaked off partly or completely from most rock surfaces at the northern wind facing coast of the island a c 130 m long and 1 2 m high beach ridge had accumulated most likely from reworked tsunami sediment boulders deposited by tsunamis are commonly assigned a high preservation potential we demonstrate for the first time that such boulders may in fact disintegrate rapidly and disappear from the record over short geological time scales given a lithology susceptible to weathering the degree of modification to the lsla mocha tsunami boulders and deposits strongly questions the applicability of inverse models using paleotsunami deposit thickness and grain size distributions to infer parameters and magnitudes of the causative tsunamis inverse models would consequently underestimate tsunami flow parameters and may result in the inference of erroneous transport modes and event magnitudes our study gives strong evidence in support of re survey studies following the deposition of tsunami sediments by tracing and quantifying the changes affecting them

a geochemical approach for identifying marine incursions implications for tsunami geology on the pacific coast of northeast japan abstract potential tsunami inundation areas can be predicted by the distribution of paleo tsunami deposits on land which are mainly composed of marine derived sands and muds these exotic sandy and muddy layers have been identified by multiple approaches however there still remain uncertainties regarding the sources and weathering trends over the long term and other useful proxies need to be investigated to identify of tsunami deposits we examined the geochemical signatures of modern tsunami deposits from the pacific coast of northeast japan 2011 tohoku tsunami and those paleo tsunami deposits taken from the tohoku district jogan 1080 calibrated ages before present cal bp and yayoi ca 2000 cal bp a geochemical ternary diagram seawater rock as metals showed the weathering trends of tsunami deposits over approximately 2000 years in the sendai plain in the tohoku in the tsunami layers from the tohoku the na ti atomic ratios markedly increased to 23 4 with an average value of 19 3 3 0 jogan and yayoi tsunami deposits which was clearly higher than those of other layers soil deposits 10 3 3 5 on average these results show that na ti ratios and other geochemical proxies are useful indicators of marine incursions in our case and may contribute to the detection of muddy tsunami deposits close to the limit of inundation

preservation potential of tsunami deposits on arid siliciclastic coasts abstract numerous post tsunami surveys have been conducted in the last two decades especially since the 2004 indian ocean tsunami these studies have documented a variety of characteristic sedimentary and erosional features that can be ascribed to known events nevertheless the question arises whether these structures are just ephemeral or have a potential to be preserved in the geological record this review describes the changes that have affected muddy to sandy siliciclastic tsunami deposits in peru each of these was surveyed in the first months after the tsunami chimbote 1996 camana 2001 and pisco paracas 2007 here we describe the changes we observed during re surveys in 2007 and 2008 it has long been recognized that onshore tsunami deposits may suffer from surficial processes tectonic movements and anthropogenic alteration earthquake induced uplift or subsidence may subject a tsunami deposit to erosion or burial respectively quick burial in rapidly subsiding coastal areas may enhance preservation deposits of the last or most landward reaching wave may be preferentially preserved if they escape erosion by subsequent tsunami waves however inland areas are also vulnerable to subaerial reworking including by wind and by humans the peruvian examples reviewed here show that the preservation of arid coast tsunami deposits depends on interactions that are more complex that hitherto perceived these involve sediment type grain size depositional setting co seismic movement bioturbation winds and anthropogenic modification in one example all traces of the tsunami have been removed or reworked by flash floods and ocean waves in another example clasts on a coastal plain from tsunami backwash began to be rounded and abraded by eolian sands immediately after the event eolian processes also smoothed and filled tsunami scours by contrast muddy tsunami deposits in certain areas escaped erosion by wind probably because of their greater cohesion in still another example 0 5 m of co seismic uplift was not enough to prevent ocean waves from removing a tsunami sand sheet that had mantled a coastal marsh the buried record of tsunami deposits on modern coasts may therefore not fully represent the vulnerability of these regions to tsunamigenic hazards

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

paleontological records indicate the occurrence of open woodlands in a dry inland climate at the present day arctic coast in western beringia during the last interglacial abstract permafrost records accessible at outcrops along the coast of oyogos yar at the dmitry laptev strait ne siberia provide unique insights into the environmental history of western beringia during the last interglacial the remains of terrestrial and freshwater organisms including plants coleopterans chironomids cladocerans ostracods and molluscs have been preserved in the frozen deposits of a shallow paleo lake and indicate a boreal climate at the present day arctic mainland coast during the last interglacial terrestrial beetle and plant remains suggest the former existence of open forest tundra with larch larix dahurica tree alder alnus incana birch and alder shrubs duschekia fruticosa betula fruticosa betula divaricata betula nana interspersed with patches of steppe and meadows consequently the tree line was shifted to at least 270 km north of its current position aquatic organisms such as chironomids cladocerans ostracods molluscs and hydrophytes indicate the formation of a shallow lake as the result of thermokarst processes steppe plants and beetles suggest low net precipitation littoral pioneer plants and chironomids indicate intense lake level fluctuations due to high evaporation many of the organisms are thermophilous indicating a mean air temperature of the warmest month that was greater than 13 c which is above the minimum requirements for tree growth these temperatures are in contrast to the modern values of less than 4 c in the study area the terrestrial and freshwater organism remains were found at a coastal exposure that was only 3 5 m above sea level and in a position where they should have been under sea during the last interglacial when the global sea level was 6 10 m higher than the current levels the results suggest that during the last warm stage the site was inland and its modern coastal situation is the result of tectonic subsidence

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

hydrographic thresholds in the western baltic sea late quaternary geology and the dana river concept abstract since the final weichselian deglaciation the water exchange between kattegat and the baltic sea and hence the palaeogeographical development of the western baltic has been controlled by a number of sills major thresholds are found at the southern entrance of the great belt and in the darss sill area the easternmost of these structures is formed by late weichselian sands at a level of 24 m below present sea level bsl at the falster rugen sand plain a second threshold consisting of till was found within the kadet channel at a level of 23 24 m bsl thus we exclude water exchange between mecklenburg bay and the arkona basin at levels below 24 m since the end of the pleistocene a high resolution sediment echosounder survey at the triple junction area of langeland channel vejsnaes channel and winds grave channel showed outcropping glacial deposits narrow channels incised at a level below 25 m bsl are filled partly with fine grained organic rich late and postglacial sediments assuming no substantial crustal movements in this area in the holocene no ancylus lake drainage at a level deeper than 25 m bsl is likely to have occurred here

acoustic evidence of a baltic ice lake drainage debrite in the northern baltic sea abstract the sudden drainage of the baltic ice lake bil at the end of the younger dryas chron was one of the major events within the pleistocene holocene boundary in scandinavia thus far the effects it might have had on sedimentary environments have been inadequately recorded outside of central and southern sweden in the present study high quality acoustic sounding data was used to examine and describe possible traces of the event from the north eastern baltic proper and gulf of finland sediments five acoustic facies were identified two of them bearing frequent indications of sediment deformation slumping sliding and homogenization the lower deformation zone is in the glacial clay deposited in the ice proximal environment the middle zone in the ice distal glacial clay and the upper zone in late glacial clay we suggest that the middle deformation unit may have basin wide significance because it represents a debrite system originating from sediment instability due to the sudden water level drop associated with the bil drainage at the transition of the younger dryas preboreal chrons

late quaternary lake records from the anadyr lowland central chukotka russia abstract three lake cores provide insight into the vegetation and climate history of the past 45 000 14c yr in the anadyr lowland a key paleogeographic link between the bering land bridge blb and interior western beringia wb although not without chronological issues these records suggest that the late pleistocene interstade approximating oxygen isotope stage ois 3 was a time of unstable environments consistent with previous interpretations for southern areas of wb and in contrast to more stable conditions inferred for northern wb a hiatus in the records during ois2 implies dry frigid environments in the anadyr lowland previous research suggested that chuktoka was a westward extension of relatively mesic environments of the blb which acted as a filter to intercontinental migrations the lowland data indicate that chukotka may have been more of a transitional zone between mesic blb and more xeric regions of western wb a structurally novel biome dominated by deciduous forest and high shrub tundra was proposed as occupying much of beringia between 11 000 and 9000 14c yr bp the unusual pollen assemblage that characterizes the lowland suggests that perhaps a second biome was also present in beringia one that was dominated by meadows with betula shrub thickets

forest or no forest implications of the vegetation record for climatic stability in western beringia during oxygen isotope stage 3 abstract two conflicting stratigraphic schemes describe the siberian karginskii interstade oxygen isotope stage 3 equivalent as having 1 relatively stable climate with environments more similar to the full glaciation or 2 variable climate with landscapes that more closely approximate contemporary ones new data from continuous lake cores and a nearly continuous section from western beringia wb suggest that both schemes are valid herb dominated communities possibly with isolated populations of larix characterized northern wb with only a slight shift from relatively warm to cool summers during the mid interstade in contrast herb and shrub tundra steppe forest tundra and modern larix forest occurred at various times in areas of southern wb suggesting greater climatic instability a thermal optimum is evident in the south during the mid interstade with modern vegetation in southeastern wb and larix forest tundra in the southwest variations in pinus pumila pollen indicate summer warm winter dry and summer warm winter wet conditions in southeastern wb these fluctuations contrast to other areas of wb where summers and probably winters were consistently arid although the interstade presents a unique interval within the late pleistocene paleodata and paleoclimatic models suggest that changes in marine conditions including sea level were likely key drivers in the regional climate history

the effect of bathymetry on tsunami characteristics at sisano lagoon papua new guinea the 1998 papua new guinea tsunami was greater than expected from its earthquake magnitude the area of significant impact was small approximately a 30 km stretch near the mouth of sissano lagoon papua new guinea to explain the localized nature of the event a submarine landslide has been conjectured to be responsible our study indicates that offshore bathymetry is critical to predicting tsunami coastal behavior model runs with newly obtained bathymetric data indicate that an earthquake fault source combined with the existing seafloor geometry may also explain the concentrated tsunami although the definitive cause of the papua new guinea tsunami remains uncertain local bathymetry had a notable effect on the wave behavior

hydro and morpho dynamic modeling of breaking solitary waves over a fine sand beach part i experimental study abstract the objectives of this work are 1 to examine the mechanisms that influence tsunami erosion and deposition mechanisms in the littoral zone via physical simulations of breaking solitary waves over a fine sand beach and 2 to provide experimental data for validation of numerical models to predict tsunami erosion and deposition processes the experiments were carried out in a 48 8 m 2 16 m 2 1 m wave flume the flume was instrumented to observe free surface elevations cross shore velocities suspended sediment concentrations vertical and cross shore pore pressure gradients near the shoreline and morphological changes in addition wave sediment interactions were observed via underwater video cameras the results are systematically analyzed to investigate the roles of wave breaking bore runup wave drawdown and wave induced pore pressure variations on tsunami erosion and deposition processes the studies showed that the wave plunging on a thin layer of water prior to reaching the shoreline did not cause much sediment suspension while the waterjet impinging directly on the beach entrained substantial amounts of sand the suspended sediments were subsequently pushed up the slope by fluid momentum as the broken wave transformed to a turbulent bore a small net deposition region was observed near the maximum runup point where both the flow velocity and the water depth were near zero a significant amount of the sediment transport occurred during the wave drawdown in the form of thick sheet flow which resulted in net erosion of the shore face and the beach a hydraulic jump formed near the wave breaking region toward the end of the drawdown which caused most of the suspended sand to deposit in the wave breaking region consequently breaking solitary waves over a sloping fine sand beach led to net erosion of the shore face and the beach net deposition in a small region immediately seaward of the max excursion point and net deposition in the wave breaking zone

the global reach of the 26 december 2004 sumatra tsunami numerical model simulations combined with tide gauge and satellite altimetry data reveal that wave amplitudes directionality and global propagation patterns of the 26 december 2004 sumatra tsunami were primarily determined by the orientation and intensity of the offshore seismic line source and subsequently by the trapping effect of mid ocean ridge topographic waveguides

diagenesis of magnetic minerals in the recent sediments of a eutrophic lake magnetic mineral assemblages in lake sediments are usulally interpreted as reflecting changing catchment erosion magnetic and chemical assemblages in a small eutrophic lake lough augher northern ireland suggest diagenetic dissolution of fine grained magnetite however probably as a result of changing redox conditions associated with eutrophication water column results show internal cycling of mn and fe from the sediments into the armxic hypolimnion calculations suggest that late summer hypolimnetic fe concentrations are controlled by formation of aulhigenic vivianite sedimentary pore water concentrations of total soluble fe and p suggest a similar process in the sediments the loss of mn from the lake by diffusion from the sediment and washout at overturn is indicated by mn budget calculations and by it marked decrease in its sedimentary concentration reflecting onset of eutrophication as indicated by diatom biostratigraph y the changes in the sediment mn profile are coincident with and in some cases identical to changes in several rnagnctic parameters the changes in magnetic stratigraphy suggest a coarsening of the magnetic grain size and reduction in the total concentration agreement with chemical profiles indicative of changing rcdox suggest that this coarsening results from dissolution of fine grained magnetite catchment stability together with other stratigraphic profiles of eutrophication and changing redox supports the conclusion that the magnetic profiles are reflecting in situ diagenetic changes rather than altered catchment processes with the data available it is not possible to identify the actual clissolution process involved or to determine whether it is chemically or bacterially controlled

the use of ostracods from marginal marine brackish waters as bioindicators of modern and quaternary environmental change abstract ostracoda microscopic aquatic crustacea from brackish waters have a great potential for ecological monitoring and palaeoenvironmental analyses in highly variable environments this has been proven in many articles during recent decades but their potential has yet to be fully developed or utilised the analysis of ostracod assemblage composition species distributions eco phenotypic variability and the analysis of stable isotopes and trace elements in ostracod shells provide valuable information on present and past water salinity temperature and chemistry hydrodynamic conditions substrate characteristics climate sea level variations oxygen and nutrient availability this article provides an overview on the application of ostracods from brackish waters for palaeoenvironmental reconstruction in the quaternary and for environmental studies in present day environments

a review of the history of the baltic sea 13 0 8 0 ka bp abstract the dynamic history of the baltic sea during the millennia following the last deglaciation has been one of the main topics for many generations of quaternary geologists around the baltic sea based on the present state of knowledge and certain hypotheses a model for the development during the baltic ice lake yoldia sea and ancylus lake stages are presented the oresund strait was the threshold of the initial stage of the baltic ice lake and was eroded down to bedrock as a result of the isostatic uplift the emerging threshold forced the baltic ice lake to rise above sea level at ca 12 0 ka bp this gradual up damming ended at ca 11 2 ka bp when the large glacial lake was lowered 5 10m by possible subglacial drainage at mt billingen a glacial readvance during the younger dryas ended a ca 400 year long land bridge between sweden and the continent by blocking the former drainage route once again the baltic ice lake had to rise above sea level to be drained over the oresund strait at ca 10 5 ka bp a gradual ice recession began and 200 years later when the receding ice sheet could not withhold the up dammed water masses the final drainage of the baltic ice lake occurred which rapidly lowered the water level within the baltic basin with ca 25 m and ended the baltic ice lake stage the next stage the yoldia sea was characterized by a complex pattern of relative sea level changes with large differences within the baltic basin a very restricted baltic sea in the south and thus an extensive landbridge at ca 9 9 ka bp a short 100 200 years saline ingression is seen in the baltic sediment records from stockholm in the north to the southernmost parts of the yoldia sea the gradually shallower strait in south central sweden the narke strait ended the saline influence 300 400 years later the two remaining outlets west of lake vanern gota alv and otteid steinselva had become too shallow to swallow the outflowing yoldia sea waters at this stage the baltic lake vanern level could thus not fall in pace with the relative sea level fall outside the outlet areas this was the isolation of lake vanern and the baltic from the sea and the beginning of the ancylus lake since the water depth of the larger gota alv outlet had to be more or less maintained the ancylus lake level had to rise in pace with the uplift of the outlet region this caused a significant and rapid transgression 10 30 m in ca 300 years in the southern baltic which flooded large areas with recently immigrated pine forests since the oresund strait during the yoldia sea stage had been uplifted more than southerly areas the ancylus transgression ended with a new drainage pathway at ca 9 2 ka bp through the darss sill area in the southern baltic and northwards through the store belt strait this so called dana river had cut off the former large land bridge the quaternary deposits of this new threshold were eroded and a fairly rapid regression set in at ca 9 0 ka bp the dana river had eroded down to the sea level which isolated lake vanern from the ancylus lake and created a land bridge between southern sweden and northwards ca 800 years later when the sea level rose above the oresund threshold marine water could enter the baltic and at ca 8 0 ka bp brackish water characterized the southern baltic this marks the end of the ancylus lake

a holocene history of dynamic water column redox conditions in the landsort deep baltic sea the modern baltic sea is the world9s largest anthropogenically forced anoxic basin using integrated geochemical records collected during integrated ocean drilling program iodp expedition 347 from the deepest and one of the most reducing sub basins in the baltic sea landsort deep we explore the degree and frequency of natural anoxia through the baltic holocene a marked decrease in carbon to sulfur ratios c s from the cores indicate the transition from the baltic ice lake to the current brackish sea which occurred about 8 5 kyrs b p following this laminations throughout sediments recording brackish deposition suggest sustained anoxia or extreme low oxygen while high molybdenum mo concentrations of 100 ppm and iron fe geochemistry suggest water column sulfide accumulation or euxinia that persisted beyond seasonal timescales during deposition of two distinct sapropel units sedimentary mo isotope values range from 1 11 to 0 50 permil which are distinctly fractionated from modern baltic seawater 2 26 to 2 67 and thus indicate that each of the sapropels experienced only weak and or oscillatory euxinia in contrast to the more stable euxinic conditions of more restricted basins a shift in 98mo starting above the lower sapropel to a distinctly more negative range suggests particularly weak and oscillatory euxinia with an enhanced contribution of manganese mn redox cycling to mo deposition relative to the lower portion of the profile this conclusion is supported by extreme sedimentary mn enrichments of up to 15 weight percent we interpret the combined data to indicate episodic but major baltic inflow events of saline and oxygenated north sea water into the anoxic landsort deep that limited the concentrations and residence time of water column sulfide and caused episodic oxide deposition considering the temporal overlap between the most reducing conditions and periods of redox instability we hypothesize that major baltic inflows as is observed today lead to short term instability while simultaneously supporting longer term baltic anoxia by strengthening the halocline ultimately our results indicate that periods more reducing than the modern baltic sea have occurred naturally over the holocene but the characteristic dynamic saline inputs have historically prevented the relatively more widespread and stable anoxia observed in other classic restricted basins and will likely continue to do so

sedimentologic and geomorphologic tsunami imprints worldwide a review abstract tsunami events with extreme effects on sedimentary transport or considerable alterations of the coastal configuration are rather rare regarding human history but considering geological timescales they occur frequently at least 100 megatsunami in different parts of the world have been recorded in the past 2000 years but presumably far more have failed to be noticed during historical times and are not mentioned either in written or oral ancient records therefore the topic of paleotsunami requires inevitable sedimentological and geomorphological research however field research concerning paleotsunami is astonishingly rare within the scientific approach and only 5 of the existing tsunami literature is related to this subject future efforts in paleotsunami research should focus on the geological evidence of these mega events to clarify their contribution to coastal forming processes this paper reviews the state of the art knowledge of sedimentologic and geomorphic imprints of tsunami along the world s coastlines in order to highlight the need for more detailed studies of paleotsunami depositional and geomorphological traces

correlation of swedish glacial varves with the greenland grip oxygen isotope record a mean varve thickness curve has been constructed for a part of the swedish varve chronology from the northwestern baltic proper the mean varve thickness curve has been correlated with the delta 1

maximum sand sedimentation distance after backwash current of tsunami simple inverse model and laboratory experiments abstract estimating the magnitude of a past tsunami is important in tsunami hazard assessment and protection in particular sand deposition data provide important information in such processes the effects of the backwash current of a tsunami on the sand distribution should be considered in estimating the historical tsunami magnitude by field survey data a simple inverse model was developed to estimate the maximum distance of a sand deposit from a tsunami considering not only sedimentation but also re erosion by the backwash current laboratory experiments were conducted to understand the characteristics of the effects of backwash current and estimate the parameters needed for the model development the proposed simple model consists of several macroscopic characteristics of both non tsunami terms such as land slope and sand characteristics and comprehensive tsunami properties such as the energy gradient of the backwash current and tsunami height it was assumed that the velocity and water depth of the backwash current are linearly approximated by the law of tsunami current conservation on a land slope to estimate the decrease in sand layer depth due to re erosion by the backwash current the tractive force of the current and the drag force of the sand removed were related with one empirical parameter e laboratory flume experiments were conducted to calibrate the parameter sensitivity analysis confirmed the effect on the changes in the value of e on the sand deposition distance to be smaller than that of other parameters in spite of many simple assumptions the estimate agreed well with the sand deposit distance of the 2011 great east japan earthquake tsunami finally the limitations and effectiveness of the model are discussed this study developed a useful method for measuring backwash in a relatively extensive land slope where the effect of the backwash current is large and regional topography and land use effects are small

different phases of the yoldia sea in the north western baltic proper four sediment cores from the north western baltic proper covering the time from the weichselian deglaciation to the present have been studied main interest is focused on the yoldia stage and especially the duration of the marine phase of this stage the lithological compositions of the sediments and results of different analyses magnetic carbonate ostracods and foraminifera have resulted in a subdivision into five stratigraphical units a e from older to younger unit a was deposited in a glaciolacustrine environment probably during the first non saline phase of the yoldia stage the first ingression of saline water is recorded in unit b brackish water ostracods and foraminifera occur exclusively in this unit which represents the only saline phase of the yoldia stage this phase lasted for less than 120 clay varve years unit c was deposited in fresh water probably during the last phase of the yoldia stage and the ancylus stage the uppermost units d and e are of holocene age and represent different phases of the litorina and post litorina stages

late quaternary development of the north western baltic proper results from the clay varve investigation within the project late quaternary development of the north western baltic proper a total of 36 piston core samples have been collected the results presented in this study are based on analyses

ages and relative sizes of pre 2004 tsunamis in the bay of bengal inferred from geologic evidence in the andaman and nicobar islands 1 geologic evidence along the northern part of the 2004 aceh andaman rupture suggests that this region generated as many as five tsunamis in the prior 2000 years we identify this evidence by drawing analogy with geologic records of land level change and the tsunami in 2004 from the andaman and nicobar islands a n these analogs include subsided mangrove swamps uplifted coral terraces liquefaction and organic soils coated by sand and coral rubble the pre 2004 evidence varies in potency and materials dated provide limiting ages on inferred tsunamis the earliest tsunamis occurred between the second and sixth centuries a d evidenced by coral debris of the southern car nicobar island a subsequent tsunami probably in the range a d 770 1040 is inferred from deposits both in a n and on the indian subcontinent it is the strongest candidate for a 2004 caliber earthquake in the past 2000 years a n also contain tsunami deposits from a d 1250 to 1450 that probably match those previously reported from sumatra and thailand and which likely date to the 1390s or 1450s if correlated with well dated coral uplift offshore sumatra thus age data from a n suggest that within the uncertainties in estimating relative sizes of paleo earthquakes and tsunamis the 1000 year interval can be divided in half by the earthquake or earthquakes of a d 1250 1450 of magnitude 8 0 and consequent tsunamis unlike the transoceanic tsunamis generated by full or partial rupture of the subduction interface the a n geology further provides evidence for the smaller sized historical tsunamis of 1762 and 1881 which may have been damaging locally

late weichselian environmental history in southeastern sweden during the deglaciation of the scandinavian ice sheet abstract late weichselian litho bio and chronostratigraphy 14 c and varves in southeastern sweden provide a detailed picture of the deglaciation pattern and dynamics shore displacement late glacial sedimentation and history of the landscape vegetation and climate two plausible glacial models were tested against lithologic chronologic and climatic data permafrost at and outside the ice margin and topographic conditions beneath the ice apparently caused inward spread of frozen glacier bed conditions this led to a buildup of a large zone of debris rich basal ice a climatic amelioration about 12 700 yr b p changed the temperature profile in the ice sheet deposition of basal melt out till began at the previously frozen glacier bed and a rapid recession of the clean ice set in thin exposed debris rich basal ice which was separated from the active ice margin about 150 yr later in this zone of stagnant ice there followed a 200 300 yr period marked by subglacial and supraglacial melt out and resedimentation forming a large hummocky transverse moraine the mild climate favored rapid plant immigration and a park tundra was established the gradual closing of the landscape was interrupted by a 100 to 150 yr period of tundra vegetation and a cool dry climate with local vegetational differences caused by differences in soil moisture about 12 000 yr b p a second climatic amelioration set in and during the next 1000 yr a birch and pine woodland gradually developed soils stabilized and empetrum heaths became abundant as the climate gradually deteriorated at the end of this period by 11 000 yr b p the area had become a tundra again with scattered birch stands dominated by herbs such as artemisia chenopodiaceae grasses and sedges some 500 yr later a birch pine woodland again succeeded and within about 500 yr the vegetation changed to a rather closed woodland as the climate ameliorated further however the time lag between climatic and vegetation change was considerable

insect faunal response to environmental changes during the last interglacial in western beringia abstract reconstruction of the last interglacial li environment could help us understand the mammoth faunal extinction and facilitate predictions of the effects of future on ecosystems this work applied the fossil insect method to a number of interglacial sites in the siberian arctic west beringia the main problem of the li in western beringia is uncertain age determinations many interesting sites are undated interpretation of warming signals is also problematic because of the special character of regional pleistocene interglacial insect communities these faunas are different from the modern ones investigation can clearly recognize interglacial faunas and with additional stratigraphic evidence correlate some units to the li insect study helps shed light on the survival of large grazing mammals in western beringia during li 1 steppe tundra areas remained in the forested regions 2 climate change provided sufficient warmth to support the steppe tundra environment in the north early holocene climate change in combination with marine transgression progressively reduced suitable habitats for large mammals until a critical point was reached insect populations were also affected but due to their small size many steppe tundra insect species remained as relicts in isolated patches of steppe tundra

microfabric study of diatomaceous and lithogenic deposition in laminated sediments from the gotland deep baltic sea the deep basins of the baltic sea are commonly anoxic and finely laminated diatomaceous sediments have been deposited at intervals throughout the last 8000 yr the origin and composition of individual laminae in gotland deep sediments have often proved difficult to characterise using traditional micropalaeontological and sedimentological studies here we present a scanning electron microscope study in which lamina down to 30 m in thickness with distinct mineralogical or micropalaeontological composition have been identified and described depositional laminae sequences in the form of couplets triplets and quadruplets of diatomaceous and lithogenic laminae are observed with an average thickness of approximately 700 m diagenetic ca rhodochrosite laminae also occur within these depositional sequences examination of the diatom assemblages suggests that these bundles of laminae represent annual deposits or varves varves are relatively uncommon and typically occur in small intervals of two to five varves which are interrupted by more diffusely laminated and homogenous sediments the origin of these more massive sediments probably relates to periodic re oxygenation of the basin on inter annual time scales and destruction of varves by bioturbation

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