limnologic analysis of gusev crater paleolake mars abstract the survey of the hydrogeologic system formed by gusev crater and ma adim vallis aeolis subquadrangle of mars points out evidence for the existence of an ice covered lake in gusev crater a first lake was formed by the drainage of the aquifer in the region surrounding gusev before the entry of ma adim vallis in the crater the existence of a former lake in gusev is deduced from the morphology of the ma adim delta its comparison with terrestrial antarctic analogs argues for the presence of an ice covered lake in gusev at the time that the southern part of the crater s rampart was breached by ma adim first release and for a subice lacustrine construction of the valley s delta our survey shows that ma adim vallis may have entered gusev crater as late as late hesperian early amazonian as part of a second lake episode the relationship between the variation of the gusev lake water level the volume of the lake and the surface of the lake bed is established by our bathymetric model the elevation of the former lake is deduced from the elevation of the mesa like structures in the delta of ma adim vallis furthermore the correlation of the crater frequency of gusev rampart with mars stratigraphic age shows that lakes may have occupied gusev crater over a period of time covering 2 gyrs from the formation of the crater to the last episode of water release from ma adim vallis though it is most likely that the lake was episodical the recurrence of abundant water in gusev crater makes this site a high priority for missions either for martian resource exploration or for the search of life

paleoseismology along the southern kuril trench inferred from diatom based sea level reconstructions 1 2 3 3 400 500 1

middle to late holocene decreased fluvial aggradation and widespread peat initiation in the ishikari lowland northern japan this study investigated the influence of sea level and climate changes on the decreased fluvial aggradation and subsequent widespread peat initiation in the middle to late holocene in the ishikari lowland which is a coastal floodplain formed in response to the postglacial sea level change by introducing a new approach to separately evaluate the rates of organic and clastic sediment input we demonstrated that the peat began to form when the fluvial sedimentation rate was significantly decreased less than 0 6 mm yr while plant macrofossil analysis suggested that lowering of water level is also important to the peat initiation such changes in sedimentary environment may be associated with the abrupt abandonment of crevasse splays the concentrated ages of the peat initiation around 5600 5000 4600 4300 and 4100 3600 cal bp suggest that an allogenic control promoted the abandonment of crevasse splays and different onset ages can be explained by different fluvial responses of the ishikari river and i

stratigraphic evidence of historical and prehistoric tsunamis on the pacific coast of central japan implications for the variable recurrence of tsunamis in the nankai trough abstract to complement historical written records of tsunamis in the nankai trough and reconstruct prehistoric tsunami records we conducted a coring survey at a coastal lowland in mie prefecture central japan we found 10 sand layers deposited from about 4500 to 500 years ago the layers are interpreted as tsunami deposits because of the presence of abundant bioclasts of marine organisms and sedimentary structures such as alternating sub layers of sand and silt rip up clasts and upward fining structures all of which are common in modern tsunami deposits at the study site no substantial seawater inundations and sand depositions have been recorded even for the largest typhoons to ever hit the region there are historical accounts of earthquake and tsunami damage along the nankai trough in 1498 1361 1096 887 and 684 ce estimated ages of the youngest three sand layers overlap well with tsunamis in 1498 1096 and 684 ce our results support the hypothesis suggested by archaeological studies that the 684 ce rupture extended farther eastward than the historical record indicates or that another tsunami occurred at some time close to 684 ce we did not find any sand layers that were definitely correlated with the tsunamis of 1361 and 887 ce which are thought to have occurred by multi segment ruptures of the nankai trough that includes the segment directly offshore from the study site if the sand layers found at the study site were deposited by the tsunamis of 1498 1096 and 684 ce and if the tsunamis of 1361 and 887 ce did not inundate the study site the tsunami recurrence interval during the relevant time period was about 400 years this finding does not support the widely believed hypothesis that earthquakes and tsunamis occur at regular intervals of approximately 100 years in this area in addition similar to the historical tsunamis intervals of geologically recorded prehistoric tsunamis at the study site vary from about 100 to 600 years the hypothesis of variable recurrence of earthquakes and tsunamis along the nankai trough should be tested by future geological and historical studies in unbiased way

tide gauge records of uplift along the northern pacific north american plate boundary 1937 to 2001 1 vertical crustal motions at 15 sites along the northern pacific north america plate boundary are determined using relative sea level changes from tide gauge records our analysis is based on monthly mean sea levels from which barometric pressure and seasonal effects are removed the records are corrected for common mode oceanographic variations these records are statistically examined for non linear behavior related to glacial isostatic tectonic and postseismic effects to estimate land uplift rates the local effect of global sea level rise is removed from the relative sea level rates slow rates of vertical motion are observed along the southern strike slip plate boundary the extremely rapid uplift of the northern strike slip boundary can be attributed entirely to viscoelastic postglacial rebound associated with tidewater glacier retreat in glacier bay and regional post little ice age deglaciation isostatic modeling indicates a mantle viscosity of 2 1019 5 1019 pa s similar to that found elsewhere along the pacific north america plate margin at yakutat near the transition of plate motion from strike slip to subduction complex non linear behavior is evident with a significant change in uplift rate following the 1979 st elias earthquake non linear uplift rates are predominant within the 1964 great alaskan earthquake near field rapid uplift at kodiak during a 3 5 year period starting mid 1964 totaled 47 8 cm anchorage seward and seldovia exhibited oscillatory uplift in the period immediately following the earthquake until mid 1972 since mid 1972 uplift rates have increased steadily at anchorage seward cordova and valdez during this period nikiski and kodiak show decreasing uplift rates

the rotational stability of an ice age earth summary predictions of glaciation induced changes in the earth s rotation vector exhibit sensitivities to earth structure that are unique within the suite of long wavelength observables associated with glacial isostatic adjustment henceforth gia and despite nearly a quarter of a century of research these sensitivities remain enigmatic previous predictions of present day true polar wander tpw speed driven by gia have indicated for example a strong sensitivity to variations in the thickness of the elastic lithosphere and the treatment phase or chemical of the density discontinuity at 670 km depth nakada recently presented results that suggest that the predictions are also sensitive to the adopted rheology of the lithosphere however his results have introduced an intriguing paradox in particular predictions generated using a model with an extremely high viscosity lithospheric lid do not converge to results for a purely elastic lithosphere of the same thickness mitrovica as cited by nakada has suggested that the paradox originates from an inaccuracy in the traditional rotation theory e g wu peltier associated with the treatment of the background equilibrium rotating form upon which any load and rotation induced perturbations are superimposed we revisit these issues using a new treatment of the linearized euler equations governing load induced rotation perturbations on viscoelastic earth models we demonstrate that our revised theory in which the background form of the planet combines a hydrostatic component and an observationally inferred excess ellipticity resolves the apparent paradox calculations using the revised theory indicate that earlier predictions based on earth models with purely elastic lithospheric lids are subject to large errors indeed previously noted sensitivities of tpw speed predictions to the thickness and rheology elastic versus viscous of the lithosphere largely disappear in the application of the new theory significant errors are also incurred by neglecting the stabilizing influence of the earth s excess ellipticity finally we demonstrate that the contribution from rotational feedback on predictions of present day rates of change of the geoid sea surface and crustal velocities are overestimated by the traditional rotation theory and this has implications for analyses of ongoing satellite e g grace missions and geodetic gps surveys

millennial scale crustal movements inferred from holocene sedimentary succession of the omoto plain northern sanriku coast northeast japan relevance for modeling megathrust earthquake cycles abstract crustal movements on a millennial timescale 103 104 years are important data for assessing the deformation of subduction zones during megathrust earthquake cycles such data did not exist until recently for the sanriku coast near the source region of the 2011 tohoku oki earthquake since the 2011 earthquake studies of holocene sedimentary successions have documented subsidence on the central to southern segment of the sanriku coast on a millennial timescale but comparable data are lacking for the northern sanriku coast this study derived millennial scale crustal movements from a well dated holocene sedimentary succession in the omoto plain on the northern sanriku coast sedimentary and fossil evidence record the following sequence of environmental changes influenced by sea level changes upward growth and landward progradation of a barrier and flood tidal delta from 10 000 9000 cal bp an estuarine environment from 9000 to 8000 cal bp after growth and progradation of the barrier and flood tidal delta ceased and a regressive delta and subsequent fluvial environment after 8000 cal bp thick deposit of delta to floodplain sediment since mid holocene is not apparent in the omoto plain whereas this feature typical of subsidence area is documented along the central sanriku coast although the absolute direction of the vertical deformation trend could not be well constrained in the study area because of compaction effects the evidence indicates that subsidence during the mid and late holocene was either absent or not noticeable on the omoto plain this difference in deformation histories corresponds to a contrast in coseismic subsidence during the 2011 earthquake between the northern sanriku coast small subsidence and the central to southern sanriku coast large subsidence the results of this study suggest that the northern and central to southern parts of the sanriku coast should be considered separately when assessing regional crustal deformation related to subduction

millennial scale stratigraphy of a tide dominated incised valley during the last 14 kyr spatial and quantitative reconstruction in the tokyo lowland central japan spatial and quantitative analysis of infilling processes of the tide dominated incised valleys beneath the tokyo lowland during the last 14 kyr was undertaken by using data from 18 sediment cores 467 radiocarbon dates and 6100 borehole logs the post last glacial maximum valley fills consist of braided river meandering river estuary spit and delta systems in ascending order the boundary between the estuary and delta systems is regarded as the maximum flooding surface the maximum flooding surface beneath the tokyo lowland is dated at 8 ka in the arakawa valley and 7 ka in the nakagawa valley this age difference is due to the migration of the tone river from the arakawa valley to the nakagawa valley at 5 ka and suggests that the widely held view that the global initiation of deltas coincided with the abrupt rise of sea level at 9 to 8 ka is true only where there has been steady sediment supply from major rivers the meandering river system is dominated by sheet like sands that were deposited during lateral migration of channels during the younger dryas and isolated vertical sands within muds that reflect vertical aggradation of channels before and after the younger dryas the transition between these channel geometries is controlled by a threshold sea level rise of 4 to 7 mm yr 1 before migration of the tone river at 5 ka the tide dominated bay in the nakagawa valley was filled by upward fining laterally accreting muds the muds accreted from the margin to the axis of the bay such lateral accretion of suspended particles derived from outside the bay has been documented in other tide dominated coastal environments and is probably common in other similar settings after the migration of the tone river the bay was filled by upward coarsening deltaic sediments

late pleistocene and halocene sea level changes in japan implications for tectonic histories and mantle rheology abstract it is very important to separate the tectonic and glacial isostatic components in the observed holocene and late pleistocene sea level changes in tectonically active areas such as japan for studying tectonic processes and for constraining mantle rheology the separation can be achieved by considering the spatial dependence of the relative sea level on the geometry of the coastline around the site where sea level is evaluated in fact the relative sea level caused by the last deglaciation at sites in the embayment such as tokyo and osaka has a sea level curve with a high stand at mid holocene and that site situated on the tip of peninsula has a sea level curve culminating towards the present the geometric effect also causes the regional difference of the sea level variations in the late glacial phase in the japanese islands the regional difference of the predicted relative sea level is about 5 m at 6000 years ago 20 m at 10 000 years ago and 30 m at 18 000 years ago comparison between observations and predictions indicates that the observations at several sites in japan are consistent with the predicted sea level variations more systematic data is required for the period 18 000 years ago to the present in order to examine tectonic processes and mantle rheology

interplate coupling beneath ne japan inferred from three dimensional displacement field 1 the northeastern japan arc is located in a typical subduction zone and is a seismically active region where large interplate earthquakes have occurred repeatedly the nationwide gps network has made it possible to investigate the crustal deformation in unprecedented detail however vertical displacements are less accurate than the horizontal ones and have not been used to constrain interplate coupling models in this study gps carrier phase data are analyzed in order to estimate three components of site displacements the result indicates uplift along the japan sea coast and subsidence along the pacific ocean coast using the vertical site velocities together with the horizontal ones as the data for a geodetic inversion method a new model of interplate coupling is constructed to explain both the horizontal and vertical velocities for the interseismic period from 1997 to 2001 the model demonstrates strong coupling in the area off miyagi and in the area off aomori through the area off tokachi including the areas of asperities the downdip limit of the locked fault zone on the plate boundary has been estimated seismologically to be at a depth of 50 60 km in northeastern japan and the distribution of slip deficits derived in this study indicates that the transition zone extends down to a depth of about 100 km

segmentation and supercycles a catalog of earthquake rupture patterns from the sumatran sunda megathrust and other well studied faults worldwide abstract after more than 100 years of earthquake research earthquake forecasting which relies on knowledge of past fault rupture patterns has become the foundation for societal defense against seismic natural disasters a concept that has come into focus more recently is that rupture segmentation and cyclicity can be complex and that a characteristic earthquake model is too simple to adequately describe much of fault behavior nevertheless recognizable patterns in earthquake recurrence emerge from long high resolution spatially distributed chronologies researchers now seek to discover the maximum minimum and typical rupture areas the distribution variability and spatial applicability of recurrence intervals and patterns of earthquake clustering in space and time the term supercycle has been used to describe repeating longer periods of elastic strain accumulation and release that involve multiple fault ruptures however this term has become very broadly applied lumping together several distinct phenomena that likely have disparate underlying causes we divide earthquake cycle behavior into four major classes that have different implications for seismic hazard and fault mechanics 1 quasi periodic similar ruptures 2 clustered similar ruptures 3 clustered complementary ruptures rupture cascades and 4 superimposed cycles segmentation is likewise an ambiguous term we identify master segments and asperities as defined by barriers to fault rupture these barriers may be persistent rarely or never traversed frequent occasionally traversed or ephemeral changing location from cycle to cycle we compile a catalog of the historical and paleoseismic evidence that currently exists for each of these types of behavior on major well studied faults worldwide due to the unique level of paleoseismic and paleogeodetic detail provided by the coral microatoll technique the sumatran sunda megathrust provides one of the most complete records over multiple earthquake rupture cycles long historical records of earthquakes along the south american and japanese subduction zones are also vital contributors to our catalog along with additional data compiled from subduction zones in cascadia alaska and middle america as well as the north anatolian and dead sea strike slip faults in the middle east we find that persistent and frequent barriers rupture cascades superimposed cycles and quasi periodic similar ruptures are common features of most major faults clustered similar ruptures do not appear to be common but broad overlap zones between neighboring segments do occur barrier regions accommodate slip through reduced interseismic coupling slow slip events and or smaller more localized ruptures and are frequently associated with structural features such as subducting seafloor relief or fault trace discontinuities this catalog of observations provides a basis for exploring and modeling root causes of rupture segmentation and cycle behavior we expect that researchers will recognize similar behavior styles on other major faults around the world

crustal tilting derived from holocene sea level observations along the east coast of hokkaido in japan and upper mantle rheology late holocene sea level observations at sites along the east coast of hokkaido in japan indicate a gradual decrease of the altitude of relative sea level eastward toward the tip of nemuro peninsula these observations in seismically active areas can be explained by glaciohydroisostatic adjustment due to the last deglaciation for an earth model with a thin lithosphere of 30 40 km thickness and with no low viscosity layer or with a 25 km lithosphere overlying a low viscosity layer less than 50 km although more data as a function of time are needed to distinguish these models thus the vertical crustal displacement associated with the subduction of the pacific plate seems to has not been cumulated on a time scale of 103 104 years

the melting history of the late pleistocene antarctic ice sheet spatial and temporal variations in the sea levels of the past 20 000 years around the globe place constraints on the melting history of the major late pleistocene ice sheets the antarctic ice sheets provided a significant contribution to the sea level rise at a rate that was approximately synchronous with the melting of the laurentide ice sheet except for the interval 9 000 6 000 years ago when it may have lagged behind minor melting of the antarctic ice sheet continued throughout the holocene

timing of terrane accretion in the neoproterozoic eopaleozoic ribeira orogen se brazil abstract new id tims u pb geochronological data of the oriental terrane combined with detailed geological data of other terranes support the presented tectonic evolutionary model for the central segment of the neoproterozoic ribeira belt southeastern brazil that can be subdivided in four major tectonic units a the occidental terrane regarded as the reworked margin of the sao francisco craton to the northwest b the paraiba do sul klippe c the oriental terrane comprising arc complexes and d the cabo frio terrane to the southeast the oriental terrane and the cabo frio terrane were progressively accreted to the reworked continental margin of the sao francisco paleoplate the occidental terrane contains pre 1 8 ga basement slivers interlayered with neoproterozoic passive margin successions andrel ndia group the oriental terrane focus of the work was firstly accreted to the sao francisco margin at ca 580 ma it displays three structural domains thrusted to nw toward the reworked sao francisco margin from west to east a the cambuci domain that is interpreted as the fore arc association b the costeiro domain that contains a distal passive margin succession intruded by the ca 790 and 635 620 ma rio negro arc complexes and c the italva domain that comprises marbles psamitic gneisses and amphibolites of ca 840 and is regarded both as the proximal passive margin of the oriental terrane or a back arc basin syn to late collisional granitoids and three metamorphic episodes ca 605 580 and 550 ma indicate a complex history for the collision i they were also described for the kaoko damara and west congo only the youngest one pan african belts located at occidental africa and are supposed to record the main episode of convergence in western gondwana a second collisional stage at ca 530 ma accreted the cabo frio terrane to the oriental terrane and is possibly related with the closure of a back arc basin located between the oriental terrane and kalahari craton that remained open until the ordovician the effects of the collision ii were also detected at the oriental terrane finally late to post tectonic granites marked the tectonic collapse of the orogenic building between 513 480 ma

chronology of lava and associated soils near san miguel new mexico abstract a lava flow in southern new mexico extends into the rio grande valley from the lower la mesa geomorphic surface a relict basin floor of middle pleistocene age three buried soils occur beneath the lava at its east end in places the lava itself is buried by a sediment in which a soil has formed pedogenic carbonate was used to calculate the age of this soil using a soil of lower la mesa as a chronological guide both the latter soil and the rio grande valley must be less than about 620 000 yr old according to dated volcanic ash and are estimated to be about 500 000 yr old based upon this age and a total of 1200 kg m2 pedogenic carbonate in the lower la mesa soil the carbonate accumulated at an average rate of about 2 4 kg m2 1000 yr using the same rate of carbonate accumulation the postlava soil took about 180 000 yr to form however not quite all of the pedogenic carbonate in this soil has been accounted for and a general figure of 200 000 yr is suggested for its approximate age the geological setting indicates that the age of the lava should be very close to the age of the postlava soil and a general figure of 200 000 yr is also suggested for approximate age of the lava this contrasts with a new k ar age of 490 000 30 000 yr which is considered to be too old however two previously obtained k ar ages of 232 000 80 000 and 154 000 119 000 yr are much closer to the estimate based on pedogenic carbonate the landscape of the soil that buries the lava differs from the landscape of the lower la mesa soil that was used as a chronological guide the rate of carbonate movement into the soils could also differ and for this reason the age obtained by pedogenic carbonate is considered tentative

late pleistocene and holocene sea level change along the australian coast abstract tectonically the australian continent is relatively stable and as such it provides a good platform for studying late pleistocene and holocene sea level change the observations indicate that present sea level was reached at about 6000 years ago and that since then level has remained constant to within a few metres considerable spatial variability in the amplitude of the emergence and in the time at which sea levels first reached their present values have been observed spatial variability has also been observed in the sea level during the last glacial maximum and during the late phase of the holocene transgression much of this variaiblity is the result of the earth s adjustment to the glacial melting in the late pleistocene early holocene time and the concomitant distribution of this meltwater into the oceans conclusions that are drawn from matching observations with this glacio hydro isostatic model include the following 1 the mantle viscosity increases with depth the average upper mantle viscosity is about 2 3 10 20 pa s and the average lower mantle defined as below 670 km depth viscosity is about 10 22 pa s the average lithospheric thickness for the coastal and offshore region is about 70 80 km lateral variations in these mantle parameters are indicated 2 the addition of melwater into the oceans did not cease 6000 years ago but continued at a reduced rate up to more recent times adding an amount of water equivalent to a 3 m sea level rise in this interval 3 the amplitude of the holocene emergence is a function inter alia of coastal geometry and significant variations occur over distances of a few hundred kilometres and more holocene highstands of 1 2 m are generally well developed at the continental margins but are less well developed or do not developed at all at offshore islands and reefs 4 variations in the time of maximum emergence also occur being earlier at upstream tidal river sites than at coastal sites at offshore reefs or islands the sea level curve lags the coastal curves by 1000 years or more 5 considerable spatial variability occurs in the sea levels at the time of the last glacial maximum with variations of up to 30 m occurring across the continental shelves 6 there is generally no need to invoke tectonic movements to explain the sea level data along the australian coast but possible exceptions occur for the perth region and for tasmania

reconstruction of holocene relative sea level change and residual uplift in the lake inba area japan abstract we collected and analyzed fossil diatoms and volcanic ash and determined 14 c ages in core samples from the lowlands around lake inba in the eastern kanto plain central japan an area where late quaternary sea level change fluvial erosion and tectonic uplift have affected a region of archeological interest we inferred holocene paleoenvironmental changes and relative sea levels on the basis of indicators such as high tide levels derived from fossil diatom assemblages as well as the stratigraphic positions of 14 c dated samples and the k ah tephra our results lead to estimates of the upper half tidal range during 6800 7000 cal yr bp of 1 7 m the holocene highstand took place at approximately 6400 6500 cal yr bp and mean sea level reached an elevation of 1 9 m however the timing of this sea level rise is earlier in the lake inba area than documented in previous studies and it is suggested that the timing of the holocene highstand may appear at least 1000 years earlier as a result of holocene residual uplift after this sea level fell abruptly around 4000 cal yr bp we also recognized a sea level fall corresponding to the yayoi regression at about 2600 cal yr bp during which the mean relative sea level may have been as low as 2 5 m after compensating for uplift subsidence or geomorphologic effects in this area

vertical deformation of the japanese islands 1996 1999 1 the interseismic vertical deformation field of the japanese islands is derived from the global positioning system gps data between 1996 and 1999 although vertical components of the gps velocities have rarely been used as important information because of their higher noise level information on the vertical deformation field will enable us to separate rigid plate motions from deformation due to interplate coupling because horizontal displacements contain both effects whereas vertical displacements contain only the interplate coupling effect the results show that 1 the precision of the vertical velocity is generally better than 2 mm yr 2 the existence of clear uplift peaks of about 8 mm yr in the shikoku and tokai regions is consistent with strong coupling with a gradual brittleplastic transition zone at the nankai and the suruga trough respectively 3 clear uplift peaks do not seem to exist in the tohoku region because the japan trench plate boundary is too far oceanward from the gps sites 4 significant uplift is obtained in the western part of hokkaido which may be associated with the long term postseismic deformation due to the 1983 japan sea and the 1993 hokkaido nansei oki m 7 6 earthquakes and 5 uplift in northeastern japan along the japan sea coast is apparently associated with distributed compression due to incipient subduction

vertical tectonic crustal movements along the japanese coastlines inferred from late quaternary and recent relative sea level changes abstract observed relative sea level rsl changes during the past 130 kyr make it possible to evaluate the vertical crustal movement due to several tectonic processes such as the subduction of oceanic plates here we infer average rates of tectonic crustal movement along the japanese coastlines on three typical timescales of 50 yr 6 kyr and 125 kyr based on tide gauge and holocene rsl observations and the altitudes of marine terraces formed at the last interglacial lig phase at 125 ka the rates on a timescale of 50 yr are derived from tide gauge data thermosteric sea level changes due to thermal expansion of the oceans and predictions due to the glacio hydro isostatic adjustment gia for the last deglaciation and also recent melting of the mountain glaciers and greenland and antarctic ice sheets those for 6 kyr and 125 kyr are based on the rsl observations and the predictions by gia modelling considering uncertainties for temporal changes in eustatic sea level for the mid to late holocene and lig phase the inferred rates for 50 yr are significantly different from those for 125 kyr in most sites particularly for sites along the coastline from eastern hokkaido to northeastern japan shikoku and south kyushu facing the pacific ocean in these regions the rates for 125 kyr and 50 yr are positive uplift and negative subsidence respectively also the observed rsl changes at 6 ka are consistent with the inferred rsl changes using the rates for 125 kyr and gia predictions in many sites but inconsistent with those for 50 yr in most sites except for a few sites these results suggest that the rates on a timescale of 50 yr are not representative of the tectonic crustal movements for timescales longer than 6 kyr in most sites along the japanese coastlines however the inferred rates on these timescales may be useful in discussing the recurrence of megathrust earthquake with its interval of 1 kyr such as the 2011 earthquake off the pacific coast of tohoku

holocene sea level change and hydro isostasy along the west coast of kyushu japan abstract mid to late holocene sea level variations have been obtained at sites along the west coast of kyushu japan sea level observations for this relatively stable area are very important for evaluating the crustal tilting associated with the hydro isostatic adjustment due to the last deglaciation and for examining the cause of underwater jomon sites submerged archeological sites during the jomon period of mid holocene typically observed in this region for these purposes we conducted systematic boring samplings at sites from goto island to tamana along the latitude of about 33 n then we performed diatom assemblage and pyrite sulfur analyses of these sediment samples and 14 c datings for intertidal shells in order to get the sea level variations for these sites observations at tsumizu faced to oomura bay with tidal range of 0 9 m show a sea level high stand of 1 m at about 5500 yr b p years before present followed by smoothly falling to the present level evidences for sea level oscillation of greater than 50 cm have not been found here relative sea levels at about 5000 yr b p are however 2 m at goto island 125 km west of tsumizu and 2 m at tamana 50 km east of tsumizu thus observations at sites along the traverse from goto island to tamana are indicative of crustal tilting of about 3 4 m for the distance of 175 km which seems to be consistent with the prediction caused by the hydro isostatic adjustment

holocene tsunami storm and relative sea level records obtained from the southern hidaka coast hokkaido japan abstract on the pacific coast of hokkaido historical documents and seismic detections spanning the last 200 years show that large earthquakes magnitude 7 8 have occurred every 50 100 years along the kuril trench geological reconstructions of past earthquakes in the region show extend records to the last 6000 years and show that unusually large m8 earthquakes occurred at intervals of several hundreds of years however the magnitude and extent of tsunamis induced by these unusually large earthquakes are not fully understood in this study we found nine anomalous sand layers embedded in peat sediments that dated between 5 5 and 1 2 ka on the southern hidaka coast hokkaido paleoenvironments reconstructed from the peat sediments using diatom chemical and mineralogical analyses showed an evolution of the site from a saltmarsh to a supratidal marsh to a back barrier wetland environment radiocarbon dating of peat sediments showed that these environmental changes correspond to a sea level fall following the mid holocene highstand the anomalous sand layers showed inland thinning and shape contacts with the underlying peat amongst the layers the most recent layer 1 7 1 2 ka was designated as a storm deposit due to its limited distribution of less than 100 m from the beach ridge eight additional sand layers from 5 5 to 2 2 ka were distributed more than 300 m away from the beach ridge and displayed a normal grading of sand particles a characteristic typical of tsunami deposits because there was no record of tsunamis striking the hidaka coast from the observed large earthquakes m7 8 that recur every 50 100 years we interpret the sand layers as tsunamis deposited by unusually large earthquakes because the eight inferred tsunami sand layers were deposited during the highstand period prior to 2 2 ka we infer that the inundation area due to tsunamis in the coastal zone has changed with relative sea level rsl in the past we highlight the necessity of evaluating the influence of long term rsl change

subsidence along the central to southern sanriku coast northeast japan near the source region of the 2011 tohoku oki earthquake estimated from the holocene sedimentary succession along a ria coast abstract along the sanriku coast northeast japan discrepancies in crustal movement have been reported between uplift on a scale of 105 years versus subsidence on a scale of 101 102 years well dated holocene incised valley fill sediments provide records of millennial scale vertical crustal movement which is key to understanding the tectonic history in this area previous studies of the age and distribution of early holocene intertidal deposits in incised valleys reported that the southern sanriku coast has subsided during the holocene at an average rate of about 1 mm yr here we studied three sediment cores tgi1 tgi2 and tgi3 collected from the tsugaruishi plain on the central sanriku coast and recognized a holocene deltaic sediment succession in all three cores in core tgi3 from the farthest inland site the intertidal sediment facies deposited from 7500 to 7000 cal bp and the overlying 6 m thick floodplain facies deposited from 7000 to 5000 cal bp are both below the present sea level because a sea level highstand due to hydroisostatic uplift around japan occurred in the mid holocene we inferred that the tsugaruishi plain subsided during the holocene and the estimated subsidence rate 1 1 1 9 mm yr at maximum is consistent with the recently reported subsidence rate along the southern sanriku coast the results of this study confirm that the central to southern sanriku coast is subsiding in contrast to an interpretation based on the study of marine terraces that this part of the coast is uplifting the empirical data presented here will be useful for constructing an earthquake cycle model related to plate subduction

late quaternary lacustrine history and paleoclimatic significance of pluvial lake cochise southeastern arizona abstract during the latest quaternary freshwater pluvial lakes intermittently formed in the topographically closed willcox basin arizona a lacustrine sequence of six separate high stands of lake cochise is documented by stratigraphic studies 19 radiocarbon ages and supplementary evidence two stands of pluvial lake cochise older than 14 000 yr b p reached elevations above 1290 m the prominent 1274 m shoreline of lake cochise which circumscribes the basin was largely created during a high stand between 13 750 and 13 400 yr b p during the holocene water filled the willcox basin three times to an elevation slightly below the crest of the 1274 m shoreline this occurred once during the early holocene around or before 8900 yr b p and twice during the later part of the middle holocene since the middle holocene only shallow ephemeral lakes have occupied the deflated central portion of ancient lake cochise a depression known as the willcox playa the lacustrine sequence of lake cochise provides an independent evaluation of late quaternary paleoclimatic reconstructions for southern arizona and the american southwest

difference in timing of maximum flooding in two adjacent lowlands in the tokyo area caused by the difference in sediment supply rate abstract the arakawa incised valley fill beneath the tokyo area japan has formed by delta progradation during holocene transgression and highstand this paper presents the integrated stratigraphy of this valley fill as deduced from three continuous sediment cores with rich radiocarbon age control and abundant data from the surrounding and compares the filling history with the adjacent nakagawa valley six depositional units make up the valley fill distinguished based on sedimentary facies in a sequence stratigraphic framework these units span from lowstand fluvial deposits latest pleistocene through retrogradational to transgressive marine deposits early and middle holocene to highstand fluvio deltaic deposits middle and late holocene the isochron and stacking pattern of sedimentary facies indicate that around 8 cal ka bp the shoreline trajectory flipped from landwards to seawards and maximum flooding occurred in the arakawa valley this is considerably earlier than in the neighboring nakagawa valley where this happened between 7 and 6 cal ka bp differences in the sediment supply at the time of transgression explain the diachronicity the findings identify the tone river which was at that time feeding the arakawa valley as a system of very large sediment supply compared to average rivers worldwide

holocene floodplain evolution in the shiribeshi toshibetsu river lowland northern japan abstract the influence of sea level and climate changes on the evolution of coastal floodplains is an important problem in fluvial geomorphology and geology however few studies have constructed detailed chronologies of floodplain evolution and the influence of sea level and climate changes at submillennial time scales is not clear this study investigated the holocene evolution of the floodplain in the shiribeshi toshibetsu river lowland hokkaido northern japan based on 13 auger cores 15 radiocarbon ages and 2 cross sections made using existing columnar sections in the study area peat beds 3 6 m thick in the uppermost holocene sediments are underlain by fluvial sediment that mainly consists of sand beds resulting from crevassing or progradational avulsion age elevation plots of the bases of these peat beds suggest that fluvial aggradation was continuous until peat formation began which in turn suggests that peat beds began to form with the cessation of fluvial deposition the chronology of floodplain sediments based on radiocarbon ages indicates that peatlands began to develop locally before ca 6500 cal bp and became moderately widespread before 5600 cal bp peatlands then became more extensive after two periods of rapid expansion during ca 5300 5000 and 4100 3900 cal bp comparison with sea level and regional climate changes suggests that the initiation of these peat beds before 5600 cal bp was associated with the deceleration of sea level rise at ca 7000 cal bp the two later periods of peatland expansion may have been strongly influenced by reduced fluvial activity due to decreased precipitation from a weakened east asian summer monsoon this interpretation suggests that floodplain evolution was controlled by sea level and climate changes and that the response to climate change occurred at submillennial time scales a comparison with the ishikari lowland on hokkaido showed that the two floodplains have slightly different histories possibly because of differences in internal characteristics of the fluvial systems such as the number and size of tributary rivers water discharge and sediment supply although their responses to sea level and climate changes were similar the fluvial response to sea level and climate changes revealed in this study has implications for studies of the holocene evolution of other coastal floodplains

polar wander of the earth associated with the quaternary glacial cycle on a convecting mantle summary observed true polar wander tpw at the present day with the speed of 1 myr 1 towards hudson bay has been generally examined based on the glacial isostatic adjustment gia for the quaternary glacial cycle the observation is however affected by the present day melting events of polar ice sheets and mountain glaciers and convective processes in the mantle in this study i examine tpw due to gia and convective processes by developing the liouville equation including these two processes referred to as generalized liouville equation here the generalized liouville equation makes it possible to evaluate the effects of convective related non forcing inertia elements i11 i22 i33 and i12 and forcing elements i13 and i23 on the polar wander for the quaternary ice age phase and clearly indicates that the excess flattening of the earth inferred from the non hydrostatic geoid stabilizes the polar motion as discussed by mitrovica et al 2005 also numerical experiments for examining the effects of time dependent convective processes on tpw indicate that reasonable convection scenarios with a time dependence in the inertia tensor of 1031 kg m2 myr 1 ricard et al 1993 insignificantly contribute to the observed present day tpw moreover the predicted tpw with magnitude of convective related forcing rates di13 dt and di23 dt larger than 5 1031 kg m2 myr 1 is significantly different from the observation these results may provide a framework for separating the contributions of gia and convection to the observed present day polar wander

sea level change glacial rebound and mantle viscosity fornorthern europe northwestern europe remains a key region for testing models of glacial isostasy because of the good geological record of crustal response to the glacial unloading since the time of the last glacial maximum models for this rebound and associated sea level change require a detailed knowledge of the ice sheet geometry including the ice thickness through time existing ice sheet reconstructions are strongly model dependent and inversions of sea level data for the mantle response may be a function of the model assumptions thus inverse solutions for the sea level data are sought that include both ice and earth model parameters as unknowns sea level data from fennoscandia the north sea the british isles and the atlantic and english channel coasts have been evaluated and incorporated into the solutions the starting ice sheet for fennoscandia is based on a reconstruction of a model by denton hughes 1981 that is characterized by quasi parabolic cross sections and symmetry about the load centre both global northwestern europe as a whole and regional subsets of the data solutions have been made for earth model parameters and ice height scaling parameters the key results are as follows 1 the response of the upper mantle to the changing ice and water loads is spatially relatively homogenous across scandinavia the north sea and the british isles 2 this response can be adequately modelled by an effective elastic lithosphere of thickness 65 85 km and by an effective upper mantle viscosity from the base of the lithosphere to the 670 km depth seismic discontinuity of about 3 4 1020 pa s the effective lower mantle viscosity is at least an order of magnitude greater 3 the ice thickness over scandinavia at the time of maximum glaciation was only about 2000 m much less than the 3400 m assumed in the denton hughes model 4 the ice profiles are asymmetric about the centre of the ice sheet with those over the western part being consistent with quasi parabolic functions whereas the ice heights over the eastern and southern regions increase much more slowly with distance inwards from the ice margin

twentieth century sea level rise inferred from tide gauge geologically derived and thermosteric sea level changes abstract relative sea level rsl changes at thirteen sites derived from tide gauge and or salt marsh sediment sequences with information for rsl changes during at least the past 200 years are used to infer the rates and causes of the global sea level rise in the twentieth century pre satellite era by incorporating spatially non uniform thermosteric sea level change and recent estimates for the melting of mountain glaciers and both polar ice sheets the main advantage of the method adopted here is that we can avoid a model dependence in the gia glacial isostatic adjustment correction and any steady tectonic effect depending on each location can be corrected for we first estimate the acceleration of sea level rise in the twentieth century at each rsl observation site and then evaluate the residuals between the sea level acceleration and thermosteric sea level rise the spatially non uniform residuals are examined to infer the rates of rsl rise due to the melting of mountain glaciers and polar ice sheets the comparison between the residuals and the predicted rates for the melting wholly supports the estimates for the melting by the fourth assessment report of the intergovernmental panel on climate change ipcc 2007 report and does not require a significant melting from the greenland ice sheet however the possible equivalent sea level rise for mountain glaciers and or antarctic ice sheet may be 0 3 mm yr 1 larger than the preferred estimate by ipcc 2007 report 0 7 mm yr 1 and the total one is 1 0 mm yr 1 the additional melting for 0 3 mm yr 1 is due to the comparison mainly for brest with long tide gauge records of 200 years also the present study indicates that the global mean thermosteric sea level rise before the rapid sea level acceleration occurred at 1990 is 0 3 mm yr 1

response of a coarse grained fluvial to coastal depositional system to glacio eustatic sea level fluctuation since the last glacial maximum an example from the tenryu river japan modern coarse grained deltas are common in tectonically active coastal zones however the stratigraphic architecture and evolution of these deltas in relation to allogenic forcing are poorly understood compared with fine grained deltas mainly because of short vertical exposure in outcrop and lack of detailed ages this paper investigates the coarse grained delta in the lower reaches of the tenryu river developed at an island arc collision coast through analyses of radiocarbon dated core sediments and borehole data the vertical successions of the proximal and distal part of the delta constitute basal coarse grained braided river deposits overlain by fine grained sand and mud accumulated under temporary marine influence the fine grained deposits in turn are covered mainly with coarse grained braided river deposits in the proximal part and upper shoreface to beach sand and gravel in the distal part at the apex of the delta in contrast the fine grained deposits are almost absent and thick gravels dominate allogenic forcing especially the rate of glacioeustatic sea level change has influenced the accumulation rates and stacking pattern of the delta most of the sediment may have been transported to the deep sea via a canyon and deposition has been minimal under the present subaerial delta before 14 ka although aggradation almost equivalent to rapid sea level rise 15 mm yr is found at the proximal part between ca 11 5 and 8 ka even with significant basin sediment yield and supply transgression occurred and gravel supply to the coast waned notably only 30 of the sediment yield from the upstream catchment might have been trapped under the present delta plain during that period this means that large amounts of sediment were transported farther offshore or alongshore in contrast slow aggradation in the proximal part and apex of the delta accompanied by progradation in the distal part might become dominant during the past 8 ka when the rate of sea level rise decreased to 10 mm yr a similar response was also observed at other holocene fluvio deltaic systems although they are very different in their geological setting such as sediment supply water discharge tectonic movement and gradient of river and shelf the results imply that the rate of sea level rise and its change have a greater significance on coastal depositional systems than other factors such as fluvial sediment supply this study contributes to an improved understanding of evolution of modern and ancient coarse grained deltas and reconstruction of sea level change from geological data

water load definition in the glacio hydro isostatic sea level equation abstract models of glacio hydro isostatic rebound and the concomitant sea level change have been progressively improved over the past three decades recently the procedures used by the group at the australian national university anu for the hydro isostatic component of the theory have been questioned quat sci rev 21 2002 409 although the details of the anu group s procedures have not been published because they are mainly computational in nature rather than representing significant conceptual advances because of this criticism we set out here in detail the procedures that have been used for the treatment of the migration of shorelines as sea levels rise and fall the effect of retreat and advancing grounded ice on shelves and shallow seas and the transitions from grounded to floating ice and vice versa we conclude that there is no basis for the criticism that these formulations and their implementation provide a high resolution and complete description of both sea level change and of the estimates of volumes of ice exchanged with the oceans the results from this formulation are confirmed by the entirely independent analyses of milne et al quat sci rev 21 2002 361 and mitrovica and milne geophys j int 2002 submitted for publication who conclude that our formulation is significantly more accurate than the procedure advocated by peltier science 265 1994 195 rev geophys 36 1998a 603 geophys res lett 25 1998b 3955

constraints on the greenland ice sheet since the last glacial maximum from sea level observations and glacial rebound models abstract geomorphological descriptions of changes in the extent of the greenland ice sheet gis have been combined with glacial isostatic adjustment models to reproduce the sea level history of greenland since the last glacial maximum lgm the contribution to past sea level change around greenland due to ice load changes outside of that region has been considerable 10 s of meters while still contributing a rise of several mm yr 1 today the isostatic contribution to relative sea level around greenland from changes in the gis is found by iteratively perturbing preliminary ice models with different lgm extents and deglaciation starting times the resulting first order model that provides the best agreement between observed and predicted sea level contributes 3 1 and 1 9 m water equivalent of additional ice relative to present day ice volumes at the lgm and younger dryas respectively the gis in most areas does not appear to have extended far onto the continental shelf the exceptions being southern most southwest greenland and northern east greenland as well as at the coalescence of the northwest greenland and innuitian ice sheets changes in ice thickness since the lgm were 500 m along the present day outer coast and 1500 m along some parts of the present day ice margin the observed mid to late holocene fall in sea level to below the present day level and the subsequent transgression seen in some areas implies that the gis retreated behind the present day margin by distances of the order of 40 km before readvancing

constraints on the age and duration of the last interglacial period and on sea level variations the relation between height and age of shorelines formed during the last interglacial period as revealed by coral reefs cannot be related directly to changes in ocean volume because of the effect of isostatic uplift in response to changes in ice sheet loading sea level changes at sites near the melting ice sheet such as bermuda and the caribbean islands differ from those along the australian margin modelling of these differences constrains the times of onset and termination of the last interglacial which are at variance with those deduced from oxygen isotope studies of deep sea cores

glacial isostatic adjustment on a rotating earth summary we extend and complete previous work to compute the influence of perturbations to the rotation vector on a suite of observables associated with glacial isostatic adjustment gia we emphasize observables relevant to present and future geodetic missions for example present day 3 d crustal motions relative sea level change and geoid or absolute sea level variations our calculations adopt spherically symmetric self gravitating maxwell viscoelastic earth models while incorporating realistic mass ice plus ocean load and rotation variations the predicted rotation induced signals are dominated by the influence of true polar wander tpw the spatial geometry of the tpw induced relative sea level geoid and radial velocity fields is primarily that of a degree two order one surface spherical harmonic the spatial variation of the horizontal velocity vectors is given by the gradient of this harmonic the peak radial and horizontal velocities are of the order of 0 5 mm yr 1 however we show that this value is sensitive to the adopted profile of mantle viscosity we also demonstrate that an accurate prediction of tpw induced sea level and 3 d crustal deformation rates requires that a realistic number of glacial cycles be incorporated into the ice load history we conclude that geodetic observations of the gia process should be analysed using a gia theory valid for a rotating planet finally we also consider variations in rotation driven by simple present day polar melting scenarios and predict the influence of these variations on a suite of geophysical observables we find that the rotational feedback associated with greenland melting is capable of significantly perturbing both relative and absolute sea level variations

on postglacial geoid subsidence over the equatorial oceans we develop two new spectral formalisms for the gravitationally self consistent solution of the sea level equation which governs the redistribution of glacial meltwater on a visco elastic earth the first is a purely spectral technique based on an extension of theory outlined by dahlen 1976 for determining the equilibrium oceanic tide on an elastic planet using this technique with a feasible spherical harmonic truncation level l 30 we can obtain convergence in the computed sea level variations within the degree range l 10 we also develop a second pseudospectral technique however which permits the construction of gravitationally self consistent solutions to much higher degree and order l 100 the pseudospectral formalism is employed here to develop a comprehensive physical explanation for the global pattern of present day sea level variations due to ongoing glacial isostatic adjustment in particular we focus upon a mechanism which we term equatorial ocean syphoning that acts to draw water toward the oceanic portion of the collapsing peripheral bulge that encircles previously glaciated regions the collapse of the forebulge induces a flow of water which is required to maintain hydrostatic equilibrium the syphoning mechanism dominates the relative sea level rsl variation in oceans in the far field of the ice sheets that is beyond the peripheral bulge during periods such as the interglacial of the past 4000 years during which the volume of the ice sheets has not apparently changed appreciably while at the same time isostatic adjustment persists the rsl change in the near field is in contrast dominated by the local vertical displacement of the solid surface finally comparison of gravitationally self consistent predictions of rsl change in the far field with the observational data at small pacific island sites has provided an upper bound of 1 to 2 m for the eustatic sea level rise produced by any recent last 3000 years melting of the antarctic ice sheet

rapid glaciation and a two step sea level plunge into the last glacial maximum the approximately 10 000 year long last glacial maximum before the termination of the last ice age was the coldest period in earth s recent climate history1 relative to the holocene epoch atmospheric carbon dioxide was about 100 parts per million lower and tropical sea surface temperatures were about 3 to 5 degrees celsius lower2 3 the last glacial maximum began when global mean sea level gmsl abruptly dropped by about 40 metres around 31 000 years ago4 and was followed by about 10 000 years of rapid deglaciation into the holocene1 the masses of the melting polar ice sheets and the change in ocean volume and hence in gmsl are primary constraints for climate models constructed to describe the transition between the last glacial maximum and the holocene and future changes but the rate timing and magnitude of this transition remain uncertain here we show that sea level at the shelf edge of the great barrier reef dropped by around 20 metres between 21 900 and 20 500 years ago to 118 metres relative to the modern level our findings are based on recovered and radiometrically dated fossil corals and coralline algae assemblages and represent relative sea level at the great barrier reef rather than gmsl subsequently relative sea level rose at a rate of about 3 5 millimetres per year for around 4 000 years the rise is consistent with the warming previously observed at 19 000 years ago1 5 but we now show that it occurred just after the 20 metre drop in relative sea level and the related increase in global ice volumes the detailed structure of our record is robust because the great barrier reef is remote from former ice sheets and tectonic activity relative sea level can be influenced by earth s response to regional changes in ice and water loadings and may differ greatly from gmsl consequently we used glacio isostatic models to derive gmsl and find that the last glacial maximum culminated 20 500 years ago in a gmsl low of about 125 to 130 metres

middle to late holocene delta plain evolution of the kimotsuki lowland kyushu southern japan abstract the evolution of delta plains and coastal floodplains is commonly believed to be influenced by sea level and climate changes however regional climate change influences on the evolution of delta plains and floodplains are poorly understood compared with responses to rapid sea level rise since the last deglaciation this study investigated the kimotsuki lowland delta plain evolution kyusyu southern japan including allogenic controls based on 28 auger cores and 28 radiocarbon ages large scale crevasse splay deposition occurred at 7000 6000 cal yr bp in response to sea level rise or increased sediment supply following a volcanic eruption afterwards widespread peat was formed in the absence of substantial fluvial sedimentation decreased precipitation from a weakened east asian summer monsoon may have dried the peatlands around 4000 cal yr bp with increasing precipitation and storminess around 2000 cal yr bp peat formation resumed at areas further from the kimotsuki river while increased overbank flows deposited organic rich mud near the river these changes may reflect an increased frequency of la nina events and higher ocean surface temperatures of the kuroshio extension the increased storminess around 2000 cal yr bp may have produced similar influences on delta plain and coastal floodplain evolution across the east asia region the results of this study suggest that regional climate change in the late holocene has a potential to control the evolution of coastal floodplains and delta plains

evaluation of holocene crustal movement in the ako plain western japan holocene sea level observations have been obtained from the ako plain in western japan in this coastal area the holocene crustal movements have been evaluated except the crustal response due to the last deglaciation by comparing observations and theoretical predictions of relative sea level rsl variations analyses of diatom assemblages and sedimentary sulphur in core sediments were used along with radiocarbon dates to derive the rsl variations a crustal movement rate between 0 2 mm and 0 2 mm per year corrected for the prediction fits well with the observed rsl index points owing to the constraint of the reconstructed palaeo mean sea level pmsl at 7300 cal bp the coast of the ako plain may have the best estimate of a tectonic subsidence rate of 0 0 2 mm yr the tectonic uplift rates along the tectonically active coast of western kobe were derived to be 0 3 0 7 mm yr and 0 11 0 45 mm yr for tarumi and tamatsu respectively relative to ako over the period concerned the relative uplift along the traverse from ako to western kobe is primarily the result of the crustal movement resulting from the active faulting of the rokko awaji fault system rfs

history of ancient megathrust earthquakes beneath metropolitan tokyo inferred from coastal lowland deposits abstract metropolitan tokyo is located directly above a subduction zone that has generated two megathrust earthquakes in the past 300 years however the timing of older megathrusts on this margin is poorly understood in this study we aim to constrain the timings of past megathrust earthquakes using coastal stratigraphy paleoecology radiocarbon dating and archaeological records from coastal lowlands an investigation of 13 boreholes in the southern coastal area of metropolitan tokyo found evidence for 4 m of uplift in a 6000 year period however we found that net vertical displacement in the last 1000 years is approximately zero results suggest that preservation of usually ephemeral lagoon sediments occurred on three occasions in the past 1000 years and radiocarbon dating results show that the timings of these preservation episodes are close to that of major historical earthquakes we thus attribute the intermittent preservation of the ephemeral lagoon deposits to coseismic uplift caused by the megathrust earthquakes the candidates of the megathrust earthquakes are events that took place in 1703 ce the 13th century and 878 ce since these events produced no net vertical displacement due to inter seismic subsidence we propose that earthquakes responsible for long term uplift of this region took place prior to the 9th century this research also demonstrates the value of preserved intertidal sediments as paleoseismological archives where net tectonic displacement is neutral

glacial rebound and relative sea level variations a new appraisal summary late pleistocene and holocene changes in sea level at technically stable shorelines contain information on the melting history of the ice sheets and on the response of the earth to changes in surface loads on time scales of 104yr some separation of parameters defining the ice loads and the earth s response can be achieved by examining sea level change at different sites around the world and at different epochs this paper examines the mathematical requirements for obtaining satisfactory solutions for the sea level equation rather than emphasizing results for the earth s response to the surface loads an examination of the equation expressing the sea level variation on a viscoelastic earth indicates that careful consideration needs to be given to both the definition of the ice load and the geometry of the redistributed water load if geophysically significant earth response parameters are to be deduced from observations of relative sea level the spectrum of the 5 x 5 area mean description of the ice load widely used in glacial rebound studies contains significant power at high degrees n 30 and can result in substantial spatial variations in sea level unless a thick lithosphere is introduced in the earth s response function a smoothed 1 1 description of the ice model avoids these high degree oscillations in relative sea level and produces satisfactory sea level results without requiring a thick lithosphere at far field sites the holocene sea levels are sensitive to the earth s response to the meltwater loading in the vicinity of the site and a high degree spatial resolution of coastline geometry is required to model the mantle flow driven by the differential loading about the site at some sites convergence of the solution to the sea level equation is not obtained even when the solution is expanded to degree 180 convergent solutions at lower degrees can be achieved by introducing earth models with a moderately thick lithosphere if high resolution ice and meltwater load models are not used then the tendency will be to overestimate the effective elastic thickness of the lithosphere estimates of mantle viscosity are also of questionable value if these high resolution models are not used a preliminary examination of sea levels at sites in both the near and far field places an upper limit of about 50 80 km on the effective lithospheric thickness these sea level observations are also consistent with an upper mantle viscosity of about 1021 pas with a lower mantle viscosity in the range of 1021 1023pa s

sea level history of the past two interglacial periods new evidence from u series dating of reef corals from south florida abstract as a future warm climate analog much attention has been directed to studies of the last interglacial period or marine isotope substage mis 5 5 which occurred 120 000 years ago nevertheless there are still uncertainties with respect to its duration warmth and magnitude of sea level rise here we present new data from tectonically stable peninsular florida and the florida keys that provide estimates of the timing and magnitude of sea level rise during the last interglacial period the last interglacial high sea stand in south florida is recorded by the key largo limestone a fossil reef complex and the miami limestone an oolitic marine sediment thirty five new high precision uranium series ages of fossil corals from the key largo limestone indicate that sea level was significantly above present for at least 9000 years during the last interglacial period and possibly longer ooids from the miami limestone show open system histories with respect to u series dating but show a clear linear trend toward an age of 120 ka correlating this unit with the last interglacial corals of the key largo limestone older fossil reefs at three localities in the florida keys have ages of 200 ka and probably correlate to mis 7 these reefs imply sea level near or slightly above present during the penultimate interglacial period elevation measurements of both the key largo limestone and the miami limestone indicate that local relative sea level was at least 6 6 m and possibly as much as 8 3 m higher than present during the last interglacial period

stepwise accelerations in the rate of sea level rise in the area north of tokyo bay during the early holocene abstract tokyo bay is situated near the triple junction of the north america pacific and philippine sea plates where relative sea level changes since the last glacial maximum lgm have been strongly affected by subduction tectonics in this study 55 sea level index points were extracted from the post lgm incised valley fills beneath the lowlands north of tokyo bay and used to construct a detailed relative sea level curve for the early holocene sea level jumps were detected at 10 1 10 0 9 2 9 1 and 8 9 8 7 ka each of 2 7 m and each followed by an acceleration in the rate of sea level rise these paired phenomena are attributed to coseismic subsidence and an interseismic decrease in the rate of uplift respectively the early holocene sea level changes in tokyo bay are characterized by remarkably short sea level jumps of

holocene environmental changes and paleo tsunami history in onuma on the southern part of the sanriku coast northeast japan abstract after the 2011 tohoku oki earthquake that occurred off the pacific coast significant problems arose concerning the pacific coastal area sanriku coast such as the lack of the historical and paleo tsunami records and the paradox between long term and short term vertical crustal movements the data necessary to solve the issues are also essential for understanding the mechanisms of tsunami generation and earthquakes and assessing the risk of large low frequency disasters thus we conducted excavation and coring surveys and reconstructed the paleoenvironment at onuma on the southern sanriku coast based on sedimentary facies age data radiocarbon dating and tephra fossils diatoms and mollusks and topography first we discussed the preservation potential of tsunami deposits considering the geomorphologic and geologic evolution of the study area subsequently we identified tsunami deposits and estimated their occurrence ages and inundation height we discovered six tsunami beds deposited during ca 5 1 ka when the preservation potential of tsunami deposits was high in the study site we divided them into two types of deposits sand and gravel these deposits reflect different sources and flow processes of paleo tsunamis therefore we estimated the heights of the paleo tsunamis that is 5 10 m for sand tsunami deposits s1 s3 deposits and 10 m for gravel tsunami deposits g1 g3 deposits the tsunami deposits were dated at 690 1040 bp s1 2240 3310 bp g1 3320 3630 bp g2 3620 4060 bp g3 4030 4400 bp s2 and 4440 5570 bp s3 this approach and the setting of the study site enabled us to evaluate not only the ages of paleo tsunami deposits but also the paleo tsunami heights moreover we estimated the paleo sea level between 8 and 7 ka based on the sedimentary facies and paleoenvironment deduced from the fossil shells and calculated the vertical crustal movement during the holocene at 0 4 to 1 0 mm yr by comparing with the theoretical relative sea level curve this information is significant for reconstructing the tectonic evolution along the subduction zone and for paleogeography to estimate the paleo tsunami magnitudes

holocene uplift derived from relative sea level records along the coast of western kobe japan abstract mid to late holocene sea level observations have been obtained from tamatsu and tarumi in western kobe japan in this tectonically active area we evaluate the local tectonic effect during the holocene by comparison between observations and predictions of sea level variations for the purpose of this study we analysed the diatom assemblages and carried out sulphur analysis of sediments these were used along with radiocarbon dates to derive relative sea level variations for the sites a rate of tectonic uplift of between 0 1 and 0 3 mm per year corrected for the prediction fits well with relative sea level rsl index points of tamatsu at 6415 5320 cal bp depending on the altitude of the rsl index point at about 5700 cal bp the best estimate of the rate of tectonic uplift for tamatsu is calculated as 0 11 0 25 mm yr over the period concerned a rate of tectonic uplift between 0 3 and 0 5 mm per year is derived for tarumi at about 7300 and 3835 3365 cal bp these values may explain the height distributions of the late pleistocene marine terraces along the coast of the western kobe providing a first approximation for rates of local crustal movements during the late quarternary

pollen derived rainfall and temperature estimates from lake tanganyika and their implication for late pleistocene water levels vol 40 pg 343 1993

crustal subsidence inferred from reconstruction of the pleistocene holocene palaeogeography in the northern lake inba area central japan to help characterise the palaeogeographic and lacustrine environmental changes that resulted from the holocene transgression and residual subsidence in the eastern kanto plain of central japan we analysed four drill cores and reviewed other core data from the southern part of the lake inba area fossil diatom assemblages yielded evidence of centennial scale palaeogeographic and salinity responses to sea level changes since the late pleistocene we determined that the seawater incursion into the lake inba area during the holocene transgression occurred at approximately 9000 yr we also recognised a late holocene regression event corresponding to the yayoi regression considered to have occurred from ca 3000 to ca 2000 yr and a subsequent transgression our data clarify some of the palaeogeographic changes that occurred in the lake inba area and document an overall trend toward lower salinity in the lake during the regression in particular the environment in lake inba changed from brackish to freshwater no later than 1000 yr from the detailed palaeogeographic and palaeo sea level reconstruction we recognised that residual subsidence occurred during the holocene in this area thus comparison of sea level reconstructions based on modelling and fossil diatom assemblages is effective in interpreting holocene long term subsidence

the effect of spatially non uniform water loads on prediction of sea level change summary numerical modelling of postglacial rebound predics a spatially variable pattern of sea level change yet many previous models predicting late pleistocene sea level change either neglect the load of water added to the oceans or assume a spatially uniform time dependent load over the whole ocean this is a poor approximation of the load near the former ice sheet since sea level change varies geographically in addition the coastline goemetry changes through time a spectral technique has been used to solve the sea level equation on an earth model with axisymmetric distribution of ice and oceans and also for a realistic ice ocean configuration the axisymmetric model is useful for demonstrating the fundamental physics involved in sea level changes caused by changes in surface loads in particular it can be seen that the elastic and gravitational response to the load is spread over a great distance whereas the viscous response is more localized a realistic ice ocean configuration has been used to demonstrate that neglect of the melt water load underestimates the amount of uplift in fennoscandia and other regions where rebound occurs in the ocean as previously noted by wu peltier 1983 in hudson bay and that movement of the coastlines and spatially varying water loads must both be included in calculations for the north sea and other near field regions with shallow seas sea level calculations including these effects and careful analysis of the sea level and ice melting record are required to determine modifications to the viscosity profile and ice model inferred by previous inaccurate models of the ocean load in the near field

some mechanical aspects of pingo growth and failure western arctic coast canada many closed system pingos are underlain by sub pingo water lenses and the same is probably true of numerous open system pingos in the early growth stage the bending of the frozen overburden of a pingo by a sub pingo water lens can be compared to the bending of a thin elastic plate although the assumptions of elastic plate theory do not apply fully to a growing pingo because time dependent plastic and creep deformation are involved the application of elastic plate theory nevertheless helps to explain the peripheral normal faulting and spring flow of pingos summit failure the ease with which elongated pingos appear to collapse and the changing roles played by the radius and overburden thickness of pingos from early growth to the cessation of growth

ice volume and sea level during the last interglacial during the last interglacial period 125 000 years ago sea level was at least several meters higher than at present with substantial variability observed for peak sea level at geographically diverse sites speculation that the west antarctic ice sheet collapsed during the last interglacial period has drawn particular interest to understanding climate and ice sheet dynamics during this time interval we provide an internally consistent database of coral u th ages to assess last interglacial sea level observations in the context of isostatic modeling and stratigraphic evidence these data indicate that global eustatic sea level peaked 5 5 to 9 meters above present sea level requiring smaller ice sheets in both greenland and antarctica relative to today and indicating strong sea level sensitivity to small changes in radiative forcing

postglacial sea level change on a rotating earth summary we present a complete derivation of the equation governing long term sea level variations on a spherically symmetric self gravitating maxwell viscoelastic planet this new sea level equation extends earlier work by incorporating in a gravitationally self consistent manner both a time dependent ocean continent geometry and the in uence of contemporaneous perturbations to the rotation vector of the planet we also outline an e cient pseudo spectral numerical methodology for the solution of this equation and present a variety of predictions based on a suite of earth models of relative sea level rsl variations due to glacial isostatic adjustment gia these results show that the contribution to the predicted rsl signal from gia induced perturbations to the rotation vector can reach 7 8 m over the postglacial period in geographic regions where the rotationally induced signal is a maximum this result is sensitive to variations in the adopted lower mantle viscosity and is relatively insensitive to variations in the adopted lithospheric thickness we also show that the rotationally induced component of rsl change is su cient to in uence previous estimates of late holocene melting events and ongoing sea level change due to giawhich were based on a rsl theory for a non rotating earth in particular estimates of antarctic melting over the last 5 kyr based on the amplitude of sea level highstands from the australian region may require an adjustment downwards of the order of 0 5 m of equivalent sea level rise furthermore present day rates of sea level change are perturbed by as much as 0 2 mm yr 1 by the rotational component of sea level change and this has implications for gia corrections of the global tide gauge record over the period from the last glacial maximum to the present we predict a distinctly non monotonic variation in the rotation induced component of rsl this is in agreement with our previous preliminary study milne mitrovica 1996 but contrasts signi cantly with predictions presented by han wahr 1989 and bills james 1996 we demonstrate that the disagreement arises as a consequence of approximations adopted in the latter studies we furthermore refute an assertion by bills james 1996 that previously published constraints on mantle viscosity and ice sheet histories which did not incorporate a rotation induced rsl component are largely invalidated by this omission

late pleistocene and holocene sea level change in the australian region and mantle rheology summary spatial and temporal variations in sea level are produced by the melting of the late pleistocene ice and by the earth s response to the redistribution in surface loads by examining different parts of the sea level curves of the past 20 000 yr from geographically widely distributed regions it becomes possible to constrain models of the melting history of the ice sheets and of the earth s rheology observations from sites away from the former arctic ice sheets such as the australian and south pacific region are particularly important for constraining the total meltwater volumes added into the oceans in the past 20 000 yr and the rates at which this occurred these observations indicate that the antarctic ice sheets provided a significant contribution to the sea level rise at a rate that was approximately synchronous with the melting of the laurentide ice sheet except for the interval 9000 6000 yr ago when it may have lagged behind minor melting of the antarctic ice sheet appears to have continued throughout the late holocene differential observations of the late holocene sea level change recorded at sites in the same region are particularly useful for estimating parameters describing the earth s non elastic response to surface loading the effective parameters used here are a lithospheric thickness an upper mantle viscosity and a lower mantle viscosity describing the response below 670 km depth with the observations used here it is not possible to separate the lithospheric thickness h from the upper mantle viscosity and the viscosity results are based on the assumption that 50 h 100 km neither do these observations provide a resolution of the depth dependence of viscosity in the upper mantle and the resulting estimates are effective parameters only differential sea levels along continental margins and along the shores of large gulfs and bays constrain the effective upper mantle viscosity to be about 1 2 1020 pa s 1 while differential values from islands of different sizes are suggestive of a somewhat lower value the lower mantle taken to be below 670 km depth viscosity is about two orders of magnitude greater than this the estimated ice and rheological models explain many of the holocene sea level observations throughout the australian and southern pacific region the tilting of continental margins as exemplified by observations of variable amplitudes of the holocene high stands and the variable times at which sea levels first reached their present level along the north queensland coast and great barrier reef is well represented by these models differential holocene sea levels observed along the narrow spencers gulf of south australia are also well explained by the models and in neither case is it necessary to invoke tectonic motions predicted late holocene sea levels at small to medium sized islands are characterized by small amplitude high stands that reached their maximum values about 4000 2000 yr ago consistent with observations from the society cook and tuamotu islands

the influence of time dependent ocean continent geometry on predictions of post glacial sea level change in australia and new zealand we describe predictions of post glacial relative sea level rsl variations in australia and new zealand that incorporate a realistic evolution of the ocean continent margin and compare these to predictions which assume that the ocean continent interface is fixed to the present day coastline geometry we find that the predicted amplitude of holocene sea level highstands in this region can be increased by more than 2 m when a time dependent ocean continent margin is incorporated into the modeling procedure future attempts to refine both mantle viscosity and late holocene melting events based on the prediction of a set of these highstands should adopt a theory that includes this extension

ma adim vallis revisited through new topographic data evidence for an ancient intravalley lake abstract based on a comprehensive study of the recent topographic map usgs mc 23 se i 2119 usgs 1991 topographical map of aeolis plus geomorphic and digital elevation we have constructed a geometric model of ma adim vallis the sedimentary history of the valley was determined by the damming of the valley by two impact craters one by the southern crater over gusev rim and the second located 120 km upstream the presence of an intravalley lake system is inferred from independent sedimentary analysis and from geomorphic evidence for valley benches peripheral and parallel topographic contour intervals of the putative intravalley lake shores suggest that the lake was covered by a thick ice sheet the longitudinal profile of the valley floor shows a peculiar reverse slope located 300 km upstream from the southern gusev crater rim we conclude that this is an accumulation of sedimentary deposits adjacent to the crater rampart which defined the northern boundary of the lake when the water level reached the lowest point of the west bank which is 0 4 km below the top of the rim of gusev crater it began to floor the surrounding plateau as the intravalley lake level raised its ice cover formed a wide lateral bench later this ponded water was funneled into gusev crater through the breaching of the southern gusev rampart by an impact crater the paleolacustrine sediments transported by the lake water that channeled through the rampart debris slope mantled the floor of gusev crater the sublacustrine sediments are promising targets for future missions and of high priority in the search for past life

on postglacial sea level summary an exact method is presented for calculating the changes in sea level that occur when ice and water masses are rearranged on the surface of elastic and viscoelastic non rotating earth models the method is used to calculate the instantaneous elastic and delayed vi scoelastic sea level changes following the partial melting of late quaternary ice sheets we find that there can be large errors in the usual assumption that changes in sea level are uniform over the ocean basins if a quantity of ice equivalent to a uniform 100 m rise in sea level melts from the laurentide and fennoscandian ice sheets then in the south pacific the instantaneous rise in sea level can be as large as 120m in the north atlantic the instantaneous rise is always less than 100 m there is a zone in the north atlantic with almost no sea level change and near greenland and norway the sea level falls rather than rises by over 100 m one thousand years after the melting a forebulge migrating towards the ice loads causes water to flow from the south pacific into the north pacific suggesting that raised beaches should occur in the south pacific the gravitational attraction of an ice mass upon a nearby ocean tends to hold sea level high in the vicinity of the ice this extra load near the ice may have a significant influence on postglacial isostatic adjustment

possible frost mounds in an ancient martian lake bed abstract circular to elongated mounds are observed in gusev crater in the aeolis subquadrangle of mars they are arranged in a large cluster and show different stages of evolution from fresh to scar structures their morphology and morphometric ratios are comparable to those of terrestrial frost mounds this study shows how the paleolacustrine environment of the ma adim vallis gusev crater hydrogeologic system may have provided a suitable environment for the formation of frost mounds alternate hypotheses of formation including volcanism fluvial erosion and eolian erosion are discussed other features such as heavings curvilinear troughs hills ridges and depressions support the idea of a sediment ice interaction the typology of the mounds and plausible mechanisms for their formation are proposed their presence could support the model of a massive water body in gusev during the amazonian and provide indicators of paleoenvironmental conditions at the time of their formation

holocene sea levels in oceanic islands implications for the rheological structure of the earth s mantle abstract relative sea levels in oceanic islands that are situated sufficiently far from glaciated regions were studied in relation to the rheological structure of the earth s mantle the local hydro isostatic adjustment associated with the mantle flow from the oceanic side to an inland side depends on the size of the island the effective upper mantle viscosity and the elastic plate thickness the relative sea level has a significant dependence on the upper mantle rheology for islands with a radius larger than 10 km but it is almost independent of the upper mantle rheology for islands with a radius less than 10 km in other words the observed sea level changes in such small islands follow the global isostatic adjustment which depends strongly on the lower mantle viscosity in fact the relative sea levels in small oceanic islands impose important constraints on the lower mantle viscosity on the other hand the effective upper mantle viscosity and the elastic plate thickness are determined by analyzing the relative sea levels for islands greater than 10 km the observed sea level curves in japan and new zealand are consistent with the effective viscosity of the upper mantle equal to 2 to 6 10 21 poises the effective elastic plate thickness for japan and new zealand is estimated to be less than 50 km and greater than 100 km respectively the thickness of the lithosphere obtained by sea level curves in japan and new zealand is compatible with the results obtained by seismological studies

near field hydro isostasy the implementation of a revised sea level equation summary we describe how the existing sea level equation incorrectly predicts the change in sea level and thus the ocean load in ice covered subgeoidal geographic regions during periods of deglaciation we go on to present a new sea level equation that overcomes this problem and we describe how this equation can be solved in a gravitationally self consistent manner by employing a well known spectral technique application of the new theory to predict relative sea level rsl histories and present day 3 d solid surface deformation rates in northeastern canada based on a single earth model characterized by a lithospheric thickness of 100 km and upper and lower mantle viscosities of 5 1020 and 5 1021 pa s respectively demonstrates that a significant error is introduced when the original theory is employed to predict the oceanic component of the surface load predictions of rsl curves show a discrepancy of 40 per cent at sites where data have been obtained and employed to constrain models of earth viscosity structure and ice sheet histories this error will significantly bias estimates of mantle viscosity structure and ice thicknesses that are based on the original theory in addition predictions of 3 d deformation rates differ by up to 25 per cent in some regions and so future applications that employ these data to constrain models of the glacial isostatic adjustment process should adopt the improved sea level theory in contrast estimates of inverse decay times from the predicted rsl curves are insensitive to within the observational error to the improvement in the surface load introduced by the new theory thus viscosity structure inferences based on this parametrization and the original sea level equation are unaffected by the error in the ocean load finally the new theory predicts a eustatic i e globally uniform rise in sea level over the postglacial period that is 11 m lower than that determined via the original theory therefore estimates of the global ice budget at the last glacial maximum based on far field rsl data and the original sea level theory will be too small by 10 per cent

an assessment of coastal tectonics along the sanriku coast northeast japan from a holocene sedimentary succession in the kuji plain abstract holocene sedimentary successions in tectonically active regions are key to understanding coastal tectonics because they provide information on millennial scale crustal movements recent analyses of holocene sedimentary successions along the sanriku coast near the source region of the 2011 tohoku oki earthquake have reported millennial scale subsidence in central to southern parts of the coast but only one comparable dataset is available for the northern part of the coast to obtain a comprehensive understanding of millennial scale crustal movements along the sanriku coast we obtained well dated holocene sediment cores from the kuji plain in the northern part of the coast these cores record a transgressive barrier lagoon system from ca 9500 to 8000 cal bp a regressive prodelta to delta front from ca 8000 to 6500 cal bp and a subsequent wave influenced shallow marine and fluvial environment the early to mid holocene relative sea level in the study area estimated from the sedimentary environment at that time is higher than that in the tsugaruishi plain central sanriku coast where millennial scale subsidence was previously inferred this discrepancy indicates that the kuji plain has been uplifted relative to the tsugaruishi plain on a millennial scale the contrast in the millennial scale crustal movements between relative uplift on the northern sanriku coast and recently inferred subsidence on the central to southern sanriku coast confirms that the sanriku coast contains multiple areas of crustal deformation furthermore this spatial distribution of millennial scale crustal movements is in good agreement with the recently reported mis 5 marine terrace distribution suggesting a continuous southward tilting trend along the sanriku coast since ca 100 ka

postglacial sea level change on a rotating earth first results from a gravitationally self consistent sea level equation we present and solve a gravitationally self consistent sea level equation which governs postglacial sea level variations on a spherically symmetric self gravitating viscoelastic and rotating earth we find that the inclusion of a glacio isostatically induced rotational excitation can significantly affect previous predictions of both present day sea level rates and postglacial sea level histories which were based on a theory that assumed a non rotating earth model to illustrate we consider present day sea level rates and tide gauge corrections along the us east coast and relative sea level curves in the far field of the late pleistocene ice sheets

tidal amplitude decreases in response to estuarine shrinkage tokyo bay during the holocene abstract tidal changes in tokyo bay during the last 10 000 years were investigated by combining a numerical model with newly compiled model bathymetries for the present day the early 20th century and every 1000 years from 4000 to 10 000 years ago over this time period sea level has changed by more than 30 m and the coastline has shifted 50 60 km tides during the early 20th century and 4000 9000 years ago were larger than those at present from 9000 to 4000 years ago the bay setting was mesotidal in contrast to the modern microtidal setting the maximum tidal level at the head of the bay was 72 higher 7000 years ago than at present and m2 tidal currents at the bay mouth from 10 000 to 9000 years ago were three times stronger than those at present when tides were compared at a fixed location the greatest tidal enhancement was found to have occurred 9000 years ago the weakening of tides over the last 9000 years can be explained by introducing the concept of estuarine shrinkage together with quarter wavelength resonance theory tidal weakening occurred in two phases during the first phase 9000 7000 years ago it was due to the rise in sea level type 2 shrinkage and during the second phase a decrease in the length of the bay was responsible type 1 shrinkage these findings can be applied to the assessment of both past tidal changes and potential future tidal changes in other elongated estuaries with lengths of several tens of kilometers

late holocene alluvial chronology and climate change in the central great plains abstract alluvium in one reach of the republican river valley south central nebraska dates to the holocene radiocarbon dating of fills underlying the two terraces in the valley reveals that entrenchment between 4500 and 3700 yr b p formed the high terrace subsequently alternating aggradation and stability occurred until sometime between 1800 and 1100 yr b p following another period of alluviation channel incision formed the low terrace general synchrony between this chronology and other late holocene fluvial chronologies of the central great plains suggests climatic control of fluvial activity the episodes of incision are tentatively correlated with different climate regimes illustrating the difficulty of attributing a given fluvial response to a particular direction of climatic change

modelling and simulation of holocene marine terrace development in boso peninsula central japan abstract in the southern part of boso peninsula central japan we can observe a series of well developed holocene marine terraces we modeled the development of these marine terraces by considering sea level fluctuation and steady land uplift the evolution of coastal landform is generally described as follows altitude change erosion deposition sea level rise land uplift in this study the erosion rate is supposed to be proportional to the dissipation rate of wave energy and the deposition rate of eroded materials to decay exponentially as they are transported seaward the rate of sea level rise is given by the time derivative of a sea level curve obtained from the sediment core records of oxygen isotope ratios steady plate subduction generally brings about steady crustal uplift subsidence independently of earthquake occurrence and so the land uplift rate is regarded as time independent on a long term average our simulation results show that a pair of sea cliff and abrasion platform is efficiently formed about a stationary point of the sea level curve the holocene sea level curve has four peaks and three troughs and so basically seven terraces are formed one by one during the past 10 000 yr however when the land uplift rate is low most of the terraces formed at older times sink in the sea when the land uplift rate is high the overlap and or reverse of older and younger terraces occur frequently and so the correspondence between the age and present altitude of terraces is not necessarily one to one taking the land uplift rate to be 3 4 mm yr we can reproduce a series of well developed holocene marine terraces in boso peninsula independently of coseismic uplifts from these simulation results we may conclude that the holocene marine terraces in boso peninsula were developed as a result of the composite process of sea level fluctuation and steady coastal uplift

quaternary paleoenvironmental variation and its impact on initial human dispersals into the japanese archipelago abstract to understand the late pleistocene human dispersals to the japanese archipelago we examine the paleobathymetric changes in and around the archipelago based on the results of recent paleoclimatological study of the japan sea that has provided millennium scale sea level changes the pleistocene mammalian faunal record e g extinct proboscideans and the paleolithic archaeological record proboscideans likely migrated from continental east asia to paleo honshu consisting of the present day honshu shikoku and kyushu islands and the ryukyu islands via land bridges across the tsushima strait and yonaguni strait during the coldest periods of the middle pleistocene mis 6 12 16 and probably 35 however no clear evidence of hominin arrival in the archipelago has been dated to the middle pleistocene further land bridges connecting continental east asia and paleo honshu were not present during the period of initial major human dispersals to the japanese archipelago i e marine isotope stage mis 3 and 2 thus initial dispersals to paleo honshu and the ryukyus were achieved by watercraft and would have involved advanced seafaring skills the paucity of archaeological sites before the onset of late mis 3 prior to 40 ka and the significant increase of archaeological sites since late mis 3 suggests that increasing population density on the east asian mainland may have been a factor for humans to disperse into the japanese archipelago

sea level and deep water temperature changes derived from benthic foraminifera isotopic records we show that robust regressions can be established between relative sea level rsl data and benthic foraminifera oxygen isotopic ratios from the north atlantic and equatorial pacific ocean over the last climatic cycle we then apply these regressions to long benthic isotopic records retrieved at one north atlantic and one equatorial pacific site to build a composite rsl curve as well as the associated confidence interval over the last four climatic cycles our proposed reconstruction of rsl is in good agreement with the sparse rsl data available prior to the last climatic cycle we compute bottom water temperature changes at the two sites and at one southern indian ocean site taking into account potential variations in north atlantic local deep water 18o our results indicate that a last glacial maximum lgm enrichment of the ocean mean oxygen isotopic ratio of 0 95 is the lowest value compatible with unfrozen deep waters in the southern indian ocean if local deep water 18o did not increase during glacials with respect to present such a value of the lgm mean ocean isotopic enrichment would impose a maximum decrease in local bottom water 18o at the north atlantic site of 0 30 during glacials

relative sea level fall since the last interglacial stage are coasts uplifting worldwide the growing interest in quantification of vertical ground motion stems from the need to understand in detail how the earth s crust behaves for both scientific and social reasons however only recently has the refinement of dating techniques made possible the use of paleoshorelines as reliable tools for tectonic studies although there are many local studies of quaternary vertical motions of coastlines we know of no comprehensive worldwide synthesis here we provide a compilation of 890 records of paleoshoreline sequences with particular emphasis on the last interglacial stage marine isotopic stage mis 5e 122 ka the quality of dating mis 5e makes it a reliable marker to evaluate vertical ground motion rates during the late quaternary on a global scale the results show that most coastal segments have risen relative to sea level with a mean uplift rate higher than 0 2 mm yr i e more than four times faster than the estimated eustatic drop in sea level the results also reveal that the uplift rate is faster on average for active margins than for passive margins neither dynamic topography nor glacio hydro isostasy may explain sustained uplift of all continental margins as revealed by the wide distribution of uplifted sequences of paleoshorelines instead we suggest that only plate tectonic processes reconcile all observations of quaternary coastal uplift we propose that long term continental accretion has led to compression of continental plates and uplift of their margins therefore this study concludes that plate tectonics processes impact all margins and emphasizes the fact that the notion of a stable platform is unrealistic these results therefore seriously challenge the evaluation of past sea levels from the fossil shoreline record

holocene sea level change and antarctic melting history derived from geological observations and geophysical modeling along the shimokita peninsula northern japan 1 a mid to late holocene sea level record based on combined geomorphological geological and micropaleontological observations was obtained from well developed wave cut benches subaerially exposed along the shimokita peninsula northern japan results indicate that the benches were formed during mid to late holocene sea level transgressions reaching a maximum highstand level of 2 m above present at about 4 000 years ago this timing corresponds to an abrupt order of magnitude decrease in sedimentation rate as recorded in a core recovered from proximal mutsu bay in addition glacio hydro isostatic adjustment due to crustal deformation in response to postglacial sea level rise was modeled and results are consistent with the reconstructed local 2 m highstand given that meltwater contributions from the major north american and european ice sheets had largely ceased by 7 000 years ago these independent lines of evidence taken together indicate that melting of the antarctic ice sheet ended by 4 000 years ago