a tsunami deposit at the cretaceous tertiary boundary in texas at sites near the brazos river texas an iridium anomaly and the paleontologic cretaceous tertiary boundary directly overlie a sandstone bed in which coarse grained sandstone with large clasts of mudstone and reworked carbonate nodules grades upward to wave ripple laminated very fine grained sandstone this bed is the only sandstone bed in a sequence of uppermost cretaceous to lowermost paleocene mudstone that records about 1 million years of quiet water deposition in midshelf to outer shelf depths conditions for depositing such a sandstone layer at these depths are most consistent with the occurrence of a tsunami about 50 to 100 meters high the most likely source for such a tsunami at the cretaceous tertiary boundary is a bolidewater impact

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

deposits flow characteristics and landscape change resulting from the september 2009 south pacific tsunami in the samoan islands the september 29th 2009 tsunami caused widespread coastal modification within the islands of samoa and northern tonga in the south pacific preliminary measurements indicate maximum runup values of around 17 m okal et al 2010 and shore normal inundation distances of up to 620 m jaffe et al 2010 geological field reconnaissance studies were conducted as part of an unesco ioc international tsunami survey team survey within three weeks of the event in order to document the erosion transport and deposition of sediment by the tsunami data collected included a general morphology and geological characteristics of the coast b evidence of tsunami flow inundation flow depth and direction wave height and runup c surficial and subsurface sediment samples including deposit thickness and extent d topographic mapping and e boulder size and location measurements four main types of sedimentary deposits were identified a gravel fields consisting mostly of isolated cobbles and boulders b sand sheets from a few to 25 cm thick c piles of organic mostly vegetation and man made material forming debris ramparts and d surface mud deposits that settled from suspension from standing water in the tsunami aftermath tsunami deposits within the reef system were not widespread however surficial changes to the reefs were observed

new constraints on volcano tectonic evolution of large volcanic edifices on venus from stereo topography derived strain estimates radial fracture systems at large volcanoes on venus offer opportunities to unravel the tectonic and magmatic evolution of such edifices however the relatively low spatial resolution 10 20 km of altimetry data for venus has hampered previous efforts at quantitative analysis of fault systems recently released stereo derived topography enables kilometer scale strain estimates to be made at tectonic features the new data resolve fault valleys grabens that cut the summit regions of two large volcanoes showing them to be deeper than previously assumed the grabens formed after most edifice building was complete we demonstrate that inflation of oblate sill like magma chambers is consistent with the magnitudes and distributions of strain at these volcanoes and estimate chamber depth radius and overpressure

cosmogenic mega tsunami in the australia region are they supported by aboriginal and maori legends mega tsunami have affected much of the coastline of australia over the past millennium such catastrophic waves have left an imprint consisting predominently of bedrock sculpturing of the rocky coastline and deposition of marine sediments to elevations reaching 130 mabove sea level one of the largest of these events occurred in eastern australia in the fifteenth century this event may be related to the mahuika impact crater found at 48 38 s 166 48 e on the continental shelf 250 km south of new zealand a comet at least 500 m in diameter formed the crater maori and aboriginal legends allude to significant cosmogenic events in the region while aboriginal legends about tsunami are common along the eastern australian coast evidence for legends that could describe the impact of a cosmogenic tsunami also exists in nw australia here geological evidence of a single megatsunami as recent as in the seventeenth century covers 1500 km of coastline we term this event wandjina after the artwork related to the legends more attention should be given to oral traditions in searching globally for other sites of significant mega tsunami

numerical modeling of tsunami waves generated by the flank collapse of the cumbre vieja volcano la palma canary islands tsunami source and near field effects 1 in this work we study waves generated by the potential collapse of the west flank of the cumbre vieja volcano cvv la palma canary island spain through numerical simulations performed in two stages i the initial slide motion and resulting free surface elevation are first calculated using a 3d navier stokes model ii generated waves are then input into a 2d horizontal boussinesq model to further simulate propagation to the nearby islands unlike in earlier work on cvv besides a similar extreme slide volume scenario of 450 km3 in our simulations i we consider several slide scenarios featuring different volumes i e 20 40 80 km3 which partly result from a geotechnical slope stability analysis ii we use a more accurate bathymetry and iii an incompressible version of a multiple fluid material navier stokes model we find wave trains for each scenario share common features in terms of wave directivity frequency and time evolution but maximum elevations near cvv significantly differ ranging from 600 to 1200 m for increasing slide volume additionally our computations show that significant energy transfer from slide to waves only lasts for a short duration order 200 s which justifies concentrating our best modeling efforts on the early slide motion phase the anticipated consequences of such wave trains on la palma and other canary islands are assessed in detail in the paper

hybrid modeling of the mega tsunami runup in lituya bay after half a century the largest mega tsunami dates back half a century to 10 july 1958 when almost unnoticed by the general public an earthquake of m w 8 3 at the fairweather fault triggered a rockslide into lituya bay the rockslide impact generated a giant tsunami at the head of lituya bay resulting in an unprecedented tsunami runup of 524 m on a spur ridge in direct prolongation of the slide axis a forest trim line and erosion down to bedrock mark the largest runup in recorded history while these observations have not been challenged directly they have been largely ignored in hazard mitigation studies because of the difficulties of even posing much less solving a well defined physical problem for investigation we study the mega tsunami runup with a hybrid modeling approach applying physical and numerical models of slide processes of deformable bodies into a u shaped trench similar to the geometry found at lituya bay c

the holocene paleo tsunami history of west australia abstract west australian coastlines experienced several tsunamis in mid holocene times to expand our knowledge about holocene tsunami events in west australia the authors extended the previously studied spatial scale to include the central and south western coastlines several of the discovered events were mid and young holocene 1000 yr bp tsunami impacts on the outer coast of the cape range peninsula five hundred kilometres to the south between cape cuvier and point quobba additional tsunami evidence exists on top of steep cliffs over a coastal stretch of 30 km the sedimentary signature of two tsunamis is documented in this area by wide ridges comprised of sand shell and clasts including coral fragments at heights of 12 30 m asl and 300 500 m inland enigmatic boulders 20 100 tons appear as cliff top megaclasts up to 100 m inland here radiocarbon dating revealed a minimum of two tsunami events at 5700 yr bp with waves depositing sandy ridges far inland and at approximately 1000 yr bp with waves depositing boulders originating from the marine environment as the first dates are congruent with previously published results for the learmonth region 500 km to the north we assume that the same mid holocene tsunami hits this long coastal section as well the southwestern coast of west australia from cape naturaliste to albany also shows signs of impacts by extreme waves here huge granite boulders 80 400 tons were dislocated and transported to heights up to 10 m above sea level the most prominent dislocated boulders were positioned at merchant rock cape naturaliste national park at islet near nanarup and in cave bay close to albany

impact of a cosmic body into earth s ocean and the generation of large tsunami waves insight from numerical modeling 1 the strike of a cosmic body into a marine environment differs in several respects from impact on land oceans cover approximately 70 of the earth s surface implying not only that oceanic impact is a very likely scenario for future impacts but also that most impacts in earth s history must have happened in marine environments therefore the study of oceanic impact is imperative in two respects 1 to quantify the hazard posed by future oceanic impacts including the potential threat of large impact generated tsunami like waves and 2 to reconstruct earth s impact record by accounting for the large number of potentially undiscovered crater structures in the ocean crust reconstruction of the impact record is of crucial importance both for assessing the frequency of collision events in the past and for better predicting the probability of future impact we summarize the advances in the study of oceanic impact over the last decades and focus in particular on how numerical models have improved our understanding of cratering in the oceanic environment and the generation of waves by impact we focus on insight gleaned from numerical modeling studies into the deceleration of the projectile by the water cratering of the ocean floor the late stage modification of the crater due to gravitational collapse and water resurge furthermore we discuss the generation and propagation of large tsunami like waves as a result of a strike of a cosmic body in marine environments

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

ritter island volcano lateral collapse and the tsunami of 1888 summary in the early morning of 1888 march 13 roughly 5 km 3 of ritter island volcano fell violently into the sea northeast of new guinea this event the largest lateral collapse of an island volcano to be recorded in historical time flung devastating tsunami tens of metres high on to adjacent shores several hundred kilometres away observers on new guinea chronicled 3 min period waves up to 8 m high that lasted for as long as 3 h these accounts represent the best available first hand information on tsunami generated by a major volcano lateral collapse in this article we simulate the ritter island landslide as constrained by a 1985 sonar survey of its debris field and compare predicted tsunami with historical observations the best agreement occurs for landslides travelling at 40 m s 1 but velocities up to 80 m s 1 cannot be excluded the ritter island debris dropped little more than 800 m vertically and moved slowly compared with landslides that descend into deeper water basal friction block models predict that slides with shorter falls should attain lower peak velocities and that 40 ms 1 is perfectly compatible with the geometry and runout extent of the ritter island landslide the consensus between theory and observation for the ritter island waves increases our confidence in the existence of mega tsunami produced by oceanic volcano collapses two to three orders of magnitude larger in scale

a pliocene mega tsunami deposit and associated features in the ranquil formation southern chile abstract an exceptionally large tsunami affected the coastline of southern chile during the pliocene its backflow eroded coarse beach and coastal dune sediments and redistributed them over the continental shelf and slope sandstone dykes and sills injected from the base of the resulting hyperconcentrated flow into underlying cohesive muds assisted in plucking up large blocks of the latter and incorporating them into the flow locally the rip up intraclasts were fragmented further by smaller scale injections to form a distinct breccia of angular to rounded mudstone clasts within a medium to coarse sandstone matrix sandstone sills in places mimic normal sedimentary beds complete with structures resembling inverse gradation planar laminae as well as ripple and trough cross lamination these were probably formed by internal sediment flow and shear stress as the semi liquefied sand was forcefully injected into cracks in borehole cores such sills can easily be misinterpreted as normal sedimentary beds which can have important implications for hydrocarbon exploration

the cretaceous tertiary boundary ktb transition in ne brazil at 7800 km from yucatan the cretaceous tertiary boundary ktb transition of the poty quarry ne brazil is the most distant locality with published accounts of chicxulub impact tsunami deposits impact spherules and ir anomaly new investigations based on sedimentology biostratigraphy mineralogy and geochemistry fail to confirm these reports latest maastrichtian planktic foraminiferal zones cf1 below an erosive and bioturbated disconformity and early danian zone p1a 1 above indicate a short hiatus with the ktb clay zone p0 the ir anomaly and the characteristic negative 13 c excursion missing the disconformity coincides with the globally recognized latest maastrichtian sea level fall above the disconformity an upward fining micro conglomerate with abundant reworked cretaceous foraminifera sub angular phosphate clasts calcitic and phosphatic spheroids along with an early danian zone p1a 1 assemblage is interpreted as a gravity flow deposit common spheroids throughout the late campanian maastrichtian appear to be chamber infillings of the benthic foraminifer dentalina alternata minor ir anomalies in thin clay layers of zone pla and no evidence of the chicxulub impact reveal that the poty quarry section remains a very important example of the complex global environmental and sea level changes observed in kt sequences from north america to central america that are commonly misinterpreted as impact tsunami events supplementary materials data for trace elements are available at www geolsoc org uk sup18585

an archean impact layer from the pilbara and kaapvaal cratons the barberton greenstone belt of south africa and the eastern pilbara block of western australia provide information about earth9s surface environments between 3 2 and 3 5 billion years ago including evidence for four large bolide impacts that likely created large craters deformed the target rocks and altered the environment we have obtained identical single zircon uranium lead ages of 3470 2 million years ago for the oldest impact events from each craton these deposits represent a single global fallout layer that is associated with sedimentation by an impact generated tsunami and in western australia is represented by a major erosional unconformity

global risk from extreme geophysical events threat identification and assessment in an increasingly interconnected world any single geophysical hazard is capable of having consequences far beyond the range of immediate physical effects most recently this was demonstrated by the 2004 asian tsunami which took the lives of citizens from 57 different nations and by hurricane katrina in august 2005 which raised fuel prices worldwide and contributed to a record uk trade deficit in the month following the devastation of new orleans on an altogether wider scale global geophysical events gges are natural phenomena capable of having wholesale deleterious consequences for the world s environment economy and society these may arise i due to a global physical effect such as an episode of severe planetary cooling in response to a volcanic super eruption or large comet or asteroid impact or ii as a result of subsidiary ramifications for the global economy and social fabric of a cataclysmic regional event such as an atlantic or pacific wide mega tsunami or a more spatially confined event at a strategically sensitive location for example the awaited major tokyo earthquake while very infrequent the wide ranging and potentially ruinous consequences of a gge for the well being of the international community make it essential that they are seriously considered within any comprehensive assessment of natural threats

flow speed estimated by inverse modeling of sandy sediment deposited by the 29 september 2009 tsunami near satitoa east upolu samoa abstract sandy deposits from the 29 september 2009 tsunami on the east coast of upolu samoa were investigated to document their characteristics and used to apply an inverse sediment transport model to estimate tsunami flow speed sandy deposits 6 to 15 cm thick formed from 25 to 250 m inland sedimentary layers in the deposits that are defined by vertical grain size variation and contacts are interpreted to have formed during onshore runup of two waves deposits at 3 locations 100 170 and 240 m inland contained two layers that are predominately normally graded 80 but contained massive sections 15 and inversely graded sections 5 at their bases about 75 of the total thickness of normally graded intervals exhibits a signature of sediment falling out of suspension at their top this type of grading termed suspension grading here was first recognized in turbidity current deposits and is characterized by the entire distribution shifting finer upwards in a layer as high settling velocity coarser material deposits first and low settling velocity finer material deposits last the jaffe and gelfenbaum 2007 inverse sediment transport model was applied to intervals within layers that exhibited suspension grading to estimate tsunami flow speed and was able to reproduce the general trends of the observed suspension grading a key unknown input in the modeling is the bottom roughness for a bottom roughness parameterization using a manning s n of 0 03 equivalent to a z0 0 006 m for the observed flow depths of 2 3 m flow speeds calculated for the 2 layers at the 3 locations were 3 8 3 6 and 3 7 m s bottom layer earlier wave and 4 4 4 4 and 4 1 m s top layer later wave at 100 170 and 240 m inland respectively these estimates are consistent with the 3 8 m s tsunami flow speed from boulder transport calculations and result in froude numbers of 0 7 1 0 when maximum measured flow depths are used because the inverse model assumes the deposit was formed by sediment falling out of suspension care must be taken to model only intervals of the deposit exhibiting suspension grading including intervals deposited by either bedload or suspended load transport convergences result in higher and sometimes unrealistic tsunami flow speed estimates

proximal impact deposits at the cretaceous tertiary boundary in the gulf of mexico a restudy of dsdp leg 77 sites 536 and 540 restudy of deep sea drilling project sites 536 and 540 in the southeast gulf of mexico gives evidence for a giant wave at cretaceous tertiary boundary time five units are recognized 1 cenomanian limestone underlies a hiatus in which the five highest cretaceous stages are missing possibly because of catastrophic k t erosion 2 pebbly mudstone 45 m thick represents a submarine landslide possibly of k t age 3 current bedded sandstone more than 2 5 m thick contains anomalous iridium tektite glass and shocked quartz it is interpreted as ejecta from a nearby impact crater reworked on the deep sea floor by the resulting tsunami 4 a 50 cm interval of calcareous mudstone containing small cretaceous planktic foraminifera and the ir peak is interpreted as the silt size fraction of the cretaceous material suspended by the impact generated wave 5 calcareous mudstone with basal tertiary forams and the uppermost tail of the ir anomaly overlies the disturbed interval dating the impact and wave event as k t boundary age like beloc in haiti and mimbral in mexico sites 536 and 540 are consistent with a large k t age impact at the nearby chicxulub crater

traces of tsunami preserved in inter tidal lacustrine and marsh deposits some examples from northeast japan the japan sea earthquake of may 26 1983 triggered a large scale tsunami that surged over the coast of ne japan and caused considerable damage the tsunami resulted in peculiar sedimentary processes on the coast depending on the hydraulic scale of the tsunami three kinds of sedimentary processes were recognized each of which left unique deposits such deposits are expected to remain in sedimentary sequences preserving remarkable sedimentary facies borehole samples drilled at different localities in coastal regions have been examined to detect traces of ancient tsunamis sedimentological and geochemical studies of the samples reveal that layered deposits similar to those developed by the tsunami of the japan sea earthquake are common in the drilled cores estimated ages of these deposits are exactly equivalent to the dates of ancient tsunamis documented in historical records these results show that the invasion of tsunamis is recorded in coastal depositional sequences from analyses of long borehol

model simulations of tsunamis generated by the storegga slides abstract a mathematical model based on the hydrodynamic shallow water equations is developed for numerical simulation of water waves generated by the submarine storegga slides on the norwegian continental slope the equations are solved numerically by a finite difference technique computations of wave amplification effects reveal run up heights for the second storegga slide between 3 and 5 m in exposed areas along the eastern coast of greenland iceland and scotland and the western coast of norway the calculated run up heights agree remarkably well with possible tsunami wave heights deduced from geological evidences along the eastern coast of scotland the generated wave heights are strongly dependent on the acceleration of the slide the effects of shear stress at the interface between the water and the slide body has turned out to be important

what is a mega tsunami abstract no unambiguous and widely accepted definition currently exists for the term mega tsunami this is in spite of the rapidly growing popularity of the expression in the scientific literature especially in recent years following the devastation wrought by the 2004 indian ocean and 2011 tohoku oki tsunamis a comprehensive literature search is revealing we find that although there have been several previous attempts at a definition the term mega tsunami has generally been applied in a rather arbitrary fashion to a number of tsunami characteristics such as wave height or amplitude at both source and distant locations run up height geographical extent and impact this haphazard situation is undesirable in response we propose a stricter definition for mega tsunami that is based solely on initial wave height amplitude at source exceeding 100 m 50 m respectively a source related definition conveniently avoids any difficulties associated with the potential influence of coastal physical attributes e g configuration bathymetry geomorphology on tsunami parameters at affected locations using this definition it becomes apparent that mega tsunamis can only include those rare events on geological timescales generated by large bolide impacts violent volcanic activity or oceanic island flank collapse and possibly extreme tsunamigenic submarine earthquakes most seismically triggered events instead fall into the group of souteigai tsunamis i e unexpected tsunamis which are considered exceptional according to historical experience and local perspectives

extended period of extinctions across the cretaceous tertiary boundary in planktonic foraminifera of continental shelf sections implications for impact and volcanism theories discussion and reply

a synthesis and review of the geological evidence for palaeotsunamis along the coast of southeast australia the evidence issues and potential ways forward abstract in recent years the role of extreme events such as tsunamis and storms in shaping coastal evolution and change has been increasingly appreciated around the world tsunami geologists are increasingly recognising the signatures of palaeotsunamis almost everywhere they look and in many cases base their interpretations on similar evidence for quaternary tsunamis first identified in australia geological research suggests that the coast of south east australia and others worldwide may have been impacted by palaeotsunamis many times larger than the catastrophic 2004 indian ocean and 2011 t hoku events in australia the debate centres on the hypothesis that the coast of south east australia preserves evidence for repeated large magnitude quaternary tsunamis if independently validated this hypothesis has profound implications for risk despite the potential importance of this hypothesis no synthesis or comprehensive review of the proposed geological evidence and chronology exists as a result it is difficult to assess the evidence and to draw conclusions about the nature of the hazard and risk along the coast this synthesis details the spatial distribution of reported palaeotsunami deposits along the coast of new south wales south east australia and summarises the distribution of different types of sedimentary and erosional evidence the age range of reported palaeotsunami deposits is identified and mapped before discussing same age chronologically correlated deposits these data are then used to draw broad conclusions about the evidence and identify future research questions to aid in the testing of the hypothesis for repeated tsunami inundation we show that 60 sites are purported to contain evidence of tsunami inundation over 650 km of the south east australian coast with a spatial concentration south of sydney geomorphic evidence distinctly different to that used elsewhere in global palaeotsunami studies is reported at 54 sites with erosional features described as the most frequent indication of inundation proposed tsunami deposits are evident at 44 sites with the dominant deposit type being imbricated boulder stacks radiocarbon dating at 39 of the sites led to a proposition of nine events during the quaternary eight of which occurred during the holocene interestingly 18 sites have no chronological data associated with them alternative interpretations are offered at six type field sites purported to contain palaeotsunami evidence attention is drawn to the disjunct between historical and geological scales of tsunami inundation in the region in addition to the contrast between the scale of reported palaeotsunamis and the robust evidence of smaller events a synthesis of research into the nature of the evidence is offered including critiques of evidence type and mechanisms a critical review of the chronological data is also presented in addition to the recalibration and analysis of published radiocarbon data the paper concludes with an outline of research questions for further work on proposed palaeotsunami sites in australia as well as a statement about likely risk in south east australia it also advocates the need for caution when interpreting evidence for palaeotsunamis elsewhere around the world when those interpretations are based on signatures originally reported in south east australia

the hulopoe gravel lanai hawaii new sedimentological data and their bearing on the giant wave mega tsunami emplacement hypothesis recognition that many oceanic islands are shaped by giant landslides has highlighted claims that the hulopoe gravel on south lanai hawaii was deposited by giant waves mega tsunami generated by such a landslide this interpretation is controversial resolution of the controversy has global implications because mass wasting of oceanic islands has been a common process for as long as hot spot volcanism has affected the ocean basins thus if mega tsunami are attendant upon the mass wasting process their effect on earth surface processes should be discernible for much of geological time and may be comparable to that resulting from bolide impacts that form astroblemes detailed facies analysis of the pebble cobble and boulder gravels that form the hulopoe gravel type section shows that the gravels are composed predominantly of basalt clasts with appreciable amounts of limestone clasts in 8 of the 14 beds present deposition was not continuous eight disconformities are recognized in the 9 2 m type section three of which are associated with truncated paleosols the hulopoe gravel was not deposited by a single tsunami at 105 ka as has been proposed one bed is clearly an alluvial deposit the origins of others are unclear but the facies data do not exclude tsunami as one of the processes that deposited individual beds within the hulopoe gravel either above or below sea level

geological and historical records of tsunami in australia abstract the indian ocean tsunami iot of 2004 has resulted in significant interest within australia about the record of tsunami for the continent because an understanding of tsunami hazard begins with a catalogue of past events here a preliminary catalogue of tsunami affecting australia is presented the catalogue contains entries for 57 tsunami events the oldest event is dated at 3 47 ga the most recent is the july 17th 2006 forty four tsunami were recorded on the new south wales coast although the nw coast of western australia records a significant number of events forty seven events have affected australia since ad1858 maximum run up for an historic event is 6 m asl whilst the maximum run up for a palaeotsunami event is reported at an elevation of at least 100 m asl twenty three percent of historic australian tsunami were generated by unknown causes and papua new guinea the solomon islands and indonesia collectively represent the most important source area of historic tsunami for australia geological records for palaeo and historic tsunami are identified and summarised the geological record of tsunami represents a potentially important source of information for australian tsunami however at the present time the geological record is both limited and controversial and future research should seek to re examine proposed geological evidence of tsunami from an analysis of this preliminary catalogue of australian tsunami a series of key research priorities have been identified to guide future research in the region

geochemistry and petrology of recycled orogen derived sediments a case study from upper precambrian siliciclastic rocks of the central iberian zone iberian massif spain abstract two areas of upper precambrian siliciclastic rocks separated from each other by 150 km were selected in the central iberian zone ciz for a petrological and geochemical study the petrology of the coarser grained rocks indicates the absence or scarcity of igneous clasts the presence of extrabasinal and intrabasinal clasts and homogeneous features of sandstones ranging from very fine to fine grained the modal data of these rocks plot close to the qt l and qm lt sides of qtfl and qmflt triangular diagrams suggesting provenance from a recycled orogen the geochemical data on the shales and sandstones from the two areas studied are very uniform both groups of rock show similar ranges of relevant major element ratios such as al 2 o 3 tio 2 17 46 21 51 17 46 21 34 for shale and sandstone respectively al 2 o 3 feo t 2 40 3 79 2 18 3 33 and feo t feo t mgo 0 71 0 77 0 68 0 76 together with parallel average rare earth element ree patterns and similar values for some key trace element ratios la th th yb th u zr hf sm nd and cr sc other trace element ratios la sc th sc cr th and cr zr are uniform in the shales group and also in the sandstones group although minor differences become apparent when both groups are compared these differences are probably related to the quartz dilution effect affecting the relative abundance of phyllosilicates in these rocks and indirectly the sc and cr contents given their covariations with al2o3 the zr yb zr y and zr th ratios of the shales are uniform the sandstones show higher and more variable values and there is no correlation between zr abundance and any of these ratios in the shales or sandstones together with the parallel ree patterns shown by both groups of rock these results suggest the absence of heavy mineral fractionation during the transport of detrital material and or the relative importance of other minerals probably phyllosilicates in the control of yb y and th abundances apparently all the groups of rocks show a remarkable geochemical homogeneity despite the distance between the sampling areas thus the petrological and chemical data are consistent and point to a very extensive homogeneous and stable source region as the most plausible contributor to the upper precambrian siliciclastic rocks in the ciz the possible relationship between this zone and n gondwana is also discussed

evaluation of trace metal enrichments from the 26 december 2004 tsunami sediments along the southeast coast of india the tsunami sediments deposited after the december 2004 tsunami were sampled immediately in the coastal environment of tamil nadu state on the southeast coast of india fifty four sediment samples were collected and 14 representative samples were selected to identify the level of metal contamination in tsunami sediments the results indicate that the sediments are mainly of fine to medium grained sand and contain significantly high contents of dissolved salts in sediments na k ca 2 mg 2 cl in water soluble fraction due to seawater deposition and evaporation correlation of acid leachable trace metals cr cu ni co pb zn indicate that fe mn oxyhydroxides might play an important role in controlling their association between them enrichment of trace metals is observed in all the locations with reference to the background samples high values of trace metals in the southern part of the study area are due to the large scale industries along the coast and they are probably anthropogenic in nature and of marine origin which could cause serious environmental problems

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

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

time and space distribution of coseismic slip of the 2011 tohoku earthquake as inferred from tsunami waveform data a multiple time window inversion of 53 high sampling tsunami waveforms on ocean bottom pressure global positioning system coastal wave and tide gauges shows a temporal and spatial slip distribution during the 2011 tohoku earthquake the fault rupture started near the hypocenter and propagated into both deep and shallow parts of the plate interface a very large slip approximately 25 m in the deep part off miyagi at a location similar to the previous 869 jogan earthquake model was responsible for the initial rise of tsunami waveforms and the recorded tsunami inundation in the sendai and ishinomaki plains a huge slip up to 69 m occurred in the shallow part near the trench axis 3 min after the rupture initiation this delayed shallow rupture extended for 400 km with more than a 10 m slip at a location similar to the 1896 sanriku tsunami earthquake and was responsible for the peak amplitudes of the tsunami waveforms and the maximum tsunami heights measured on the northern sanriku coast 100 km north of the largest slip the average slip on the entire fault was 9 5 m and the total seismic moment was 4 2 1022 n m m w 9 0 the large horizontal displacement of seafloor slope was responsible for 20 40 of tsunami amplitudes the 2011 deep slip alone could reproduce the distribution of the 869 tsunami deposits indicating that the 869 jogan earthquake source could be similar to the 2011 earthquake at least in the deep plate interface the large tsunami at the fukushima nuclear power station is due to either the combination of a deep and shallow slip or a triggering of a shallow slip by a deep slip which was not accounted for in the previous tsunami hazard assessments online material table of estimated slip for all subfaults at 0 5 min invervals

chevrons are not mega tsunami deposits a sedimentologic assessment since the introduction of the term chevron for large v or u shaped bed forms in egypt and the bahamas others have adopted the term to describe large scale coastal bed forms in australia madagascar and elsewhere these authors interpret chevron bed forms as deposits of mega tsunamis resulting from holocene oceanic asteroid impacts we reason that chevron type bed forms are common and are present far enough from the coast to preclude tsunami genesis moreover we argue that chevrons are not mega tsunami deposits by modeling tsunami behavior and evaluating sediment transport conditions under which such features formed we model the southern madagascar case with an impact source in the indian ocean and show that a modeled wave approach is inconsistent with chevron orientation we then evaluate sediment transport conditions under which these chevron bed forms could persist i e bed load transport in our analysis no conditions specified generate pure bed load transport and most result in pure suspended load transport

tektite bearing deep water clastic unit at the cretaceous tertiary boundary in northeastern mexico the hypothesis of cretaceous tertiary k t boundary impact on yucatan mexico predicts that nearby sites should show evidence of proximal impact ejecta and disturbance by giant waves an outcrop along the arroyo el mimbral in northeastern mexico contains a layered clastic unit up to 3 m thick that interrupts a biostratigraphically complete pelagic marl sequence deposited at more than 400 m water depth the marls were found to be unsuitable for determining magnetostratigraphy but foraminiferal biostratigraphy places the clastic unit precisely at the k t boundary we interpret this clastic unit as the deposit of a megawave or tsunami produced by an extraterrestrial impact the elastic unit comprises three main subunits 1 the basal spherule bed contains glass in the form of tektites and microtektites glass spherules replaced by chlorite smectite and calcite and quartz grains showing probable shock features this bed is interpreted as a channelized deposit of proximal ejects 2 a set of lenticular massive graded laminated beds contains intraclasts and abundant plant debris and may be the result of megawave backwash that carried coarse debris from shallow parts of the continental margin into deeper water 3 at the top several thin ripple beds composed of fine sand are separated by clay drapes they are interpreted as deposits of oscillating currents perhaps a seiche an iridium anomaly 921 23 pg g is observed at the top of the ripple beds our observations at the mimbral locality support the hypothesis of a k t impact on nearby yucatan

one hundred and thirty years since darwin reshaping the theory of atoll formation april 2012 marked the 130th anniversary of the death of charles darwin one of many significant contributions he made to science was the subsidence theory of atoll formation which he penned on 12 april 1836 during the voyage of the beagle through the pacific darwin s elegant theory founded on the premise of a subsiding volcano and the corresponding upward growth of coral reef was astonishing for the time considering the absence of an underpinning awareness of plate tectonics his theory has endured until modern times in spite of a number of opposing ideas and permutations and has an enviable longevity amongst paradigms in geomorphology darwin frequently alluded to the generally circular morphology of the atoll shape yet the reality is that many atolls are neither circular nor elliptical instead possessing irregular morphologies in particular many exhibit major arcuate bight like structures abls in their plan form these departures from the circular form are indicative of geomorphological proc