spatial distribution of intermediate depth earthquakes with horizontal or vertical nodal planes beneath northeastern japan abstract the 1993 kushiro oki off kushiro earthquake m jma 7 8 is one of the largest intermediate depth earthquakes that have occurred in northeastern japan this earthquake is a notable event that has a nearly horizontal fault plane extended from the lower seismic plane of the double planed seismic zone toward the upper seismic plane we have examined the spatial distribution of focal mechanism solutions of deep and intermediate depth earthquakes beneath northeastern japan concerning this peculiar event analyses of 127 new solutions along with existing solutions confirm the previous results on essential features of their spatial distribution the predominant types of solutions are down dip compression in the upper plane except beneath eastern hokkaido and down dip extension in the lower plane p axes in the upper seismic plane and t axes in the lower plane are in the direction of plate convergence beneath hokkaido however t axes show significant deviation from the direction of plate convergence the stress axes beneath the junction between the northeastern japan arc and the kuril arc exhibit slight deviation from those in the adjacent areas suggesting slab distortion beneath the junction we next investigate the spatial distribution of events with horizontal nodal planes as candidates for events with similar focal mechanisms to the kushiro oki earthquake the activity of earthquakes with horizontal nodal planes is definitely high in the lower plane especially beneath hokkaido many of them have similar focal mechanisms to the kushiro oki earthquake indicating that the kushiro oki earthquake is not exceptional but is a typical event in the region however the fault planes of these events are variable in space some events are known to have vertical fault planes there are shallow and deep depth bounds and a southwestern boundary for the events with horizontal fault planes these facts suggest that the horizontal faulting is probably caused by some regional stress concentration owing to the unbending and the distortion of the segmented slab at the junction

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

on the use of tide gauges to determine altimeter drift topex measurements of sea level variability have been compared to tide gauge measurements from 40 sites and to dynamic topography measurements computed from temperatures recorded at 23 tropical ocean global atmosphere toga tropical atmosphere ocean tao buoys in the eastern pacific and mean temperature salinity profiles buoy data in the western pacific were not used because of large long term slopes in the data that appear to be due to interannual salinity variations the relative drift between topex and the two different in situ sets of data agree within 1 mm yr 1 with a weighted average of 2 6 mm yr 1 and an estimated uncertainty of 1 5 mm yr 1 if values from an internal calibration of the topex altimeter are applied the consistency of the two relative drifts suggests that the slope is due at least in part to a drift in the topex measurement a substantial portion of this drift may be due to a drift in the topex microwave radiometer tmr since comparisons with three independent external measurements indicate a drift in sea level due to the tmr measurement of about 2 mm yr 1

early middle paleozoic intraplate orogeny in the ogcheon belt south korea a new insight on the paleozoic buildup of east asia the polycyclic ogcheon belt of south korea represents the boundary between two precambrian blocks investigation on the timing and kinematics of the block agglomeration is of considerable bearing on the understanding of the constitution of the asian continent we report here structural evidence showing that the earlier tectonic event dates back to early middle paleozoic the ogcheon tectonism or orogeny the ductile piling up of nappes of the ogcheon belt corresponds to an intracontinental orogeny involving the opening and the subsequent closure of an aborted rift and not of a wide oceanic area the nappes contain unequivocal evidence for ductile shearing with a northwest over southeast sense of movement field evidence includes the presence of s1 and s1 2 foliations bearing an extensive stretching lineation perpendicular to the belt associated with a strongly noncoaxial deformation regime the f1 isoclinal folds are commonly a type and sheath folds whose axes are parallel to the stretching lineation whereas the southeast facing f2 recumbent folds have subhorizontal axes parallel to the belt all lines of evidence unconformity superposed deformations age of the metamorphism etc imply that the d1 2 ogcheon tectonism is pre middle carboniferous late silurian early devonian the subsequent indosinian middle triassic f3 upright synfolial folds that trend nne ssw and later structures clearly overprint the middle paleozoic ductile thrusts and isoclinal folds the early paleozoic ogcheon supergroup is formed of a thick volcanosedimentary pile deposited above an early platform sequence in a rift basin on the basis of the geochemical characteristics of the metavolcanics it appears that oceanization did not occur and ogcheon rift aborted soon after it was formed we suggest that middle paleozoic ductile nappe structures have been formed by the structural inversion of the rift extensional features during the ductile stacking episode the early formed foliation and isoclinal folds have been folded in a continuum during the same tectonic event middle carboniferous terrigenous formations have been deposited unconformably upon folded and thrust older rocks a tentative correlation with early paleozoic imjingang qinling and cathaysian belts within the asian continent reveals that ogcheon rift was emplaced within the south china plate and that imjingang belt should represent the limit between north and south china blocks in the korean peninsula

global sea level rise published values for the long term global mean sea level rise determined from tide gauge records exhibit considerable scatter from about 1 mm to 3 mm yr this disparity is not attributable to instrument error long term trends computed at adjacent sites often agree to within a few tenths of a millimeter per year instead the differing estimates of global sea level rise appear to be in large part due to authors using data from gauges located at convergent tectonic plate boundaries where changes of land elevation give fictitious sea level trends in addition virtually all gauges undergo subsidence or uplift due to postglacial rebound pgr from the last deglaciation at a rate comparable to or greater than the secular rise of sea level modeling pgr by the ice 3g model of tushingham and peltier 1991 and avoiding tide gauge records in areas of converging tectonic plates produces a highly consistent set of long sea level records the value for mean sea level rise obtained from a global set of 21 such stations in nine oceanic regions with an average record length of 76 years during the period 1880 1980 is 1 8 mm yr 0 1 this result provides confidence that carefully selected long tide gauge records measure the same underlying trend of sea level and that many old tide gauge records are of very high quality

geodynamics of the ogcheon belt south korea abstract the ogcheon belt is a stack of synmetamorphic southeastward verging nappes resulting from the deformation of a volcanosedimentary sequence deposited in an early palaeozoic rift which was affected by polyphase tectonics its pre cretaceous structure results from three main orogenic events the ogcheon late silurian devonian indosinian late permian triassic and yenshanian middle jurassic early cretaceous tectonic phases the external autochthonous or para autochthonous units represent platform zones with shallow water deposits whereas rift facies characterize the internal domain the yeongweol sequence forming an outer shelf on the southeastern margin of the rift displays affinities with the jiangnan basin of south china it is in wrench fault contact with the easternmost duwibong sequence correlated with the north china north korea platform in the internal metamorphic units post cambrian early ordovician pelitic and turbiditic rift metasediments overlie a thin cambrian or cambrian ordovician early platform sequence two subdomains are distinguished the upper units chung ju and pibaryeong units representing the deep axial part of the basin contain distal flyshoids and large olistoliths derived from the northwestern narrow margin the lower units turung san poeun and iwharyeong are related to the wide margin located between the deep rift domain and the stable southeastern platform the latter transitional domain is characterized by thick submarine debris flows and volcanics of alkali or transitional tholeiitic affinity the volcanic activity and mass gravity flow sedimentation are closely related to the crustal thinning and subsequent rifting and tilting lithostratigraphic evidence allows the correlation of the unfossiliferous rift metasediments with the cambrian ordovician platform sequence in one single basin the post middle silurian pre mid carboniferous ogcheon ensialic orogeny resulted in the closure of the rift with relatively minor effects in the platform area it gave rise to an intracontinental fold thrust belt without ophiolites this tectonic event may have been contemporaneous with early palaeozoic tectonism in the quinling belt in central china and in the southeast china fold belt the definitive constitution of the sino korean craton took place before the mid carboniferous and molasse sedimentation was initiated on a single platform located on the western edge of the yakuno oceanic basin of southwest japan in late permian and early triassic times the closure of the oceanic area and the subsequent westward collision of the honshu block are marked in korea by the intracratonic indosinian tectonism since late triassic times predominantly transcurrent movements have occurred along nne ssw faults associated with syntectonic intermontane troughs and important granitization

the impact of various methods of wave transfers from deep water to nearshore when determining extreme beach erosion abstract several levels of increasing complexity of transferring wave information from offshore to nearshore have been studied to quantify their influence on extreme beach erosion estimates beach profiles which have been monitored since 1976 were used to estimate extreme beach erosion and compared to predictions examination of the wave propagation assumptions revolves around two types of offshore to nearshore transfer excluding or including wave breaking and bottom friction a second complication is whether still water level variations ocean tide plus storm surge are included the inclusion of various combinations of wave propagation processes other than shoaling and refraction in the wave transfer function changes on the extreme erosion distribution tail through lowering estimates above one year return period this brings the predicted tails closer to the observations but does not capture the upper limit of storm demand implied by the extensive beach profile data set including wave breaking has a marked effect on probabilistic estimates of beach erosion the inclusion of bottom friction is less significant the inclusion of still water level variability in the wave transfer calculation had minimal impact on results for the case study site where waves were transferred from offshore to water at 20 m depth these changes were put into perspective by comparing them to changes resulting from limiting beach erosion by adjusting the statistical distributions of peak wave height and storm duration to have maximum limits we conclude that the proposed improvements on wave transformation methods are as significant as limiting wave erosion potential and worth including

volatile emission during the eruption of baitoushan volcano china north korea ca 969 ad magma volume dre 24 5 km3 the main phase ca 95 vol is represented by comenditic tephra deposited dominantly as widespread fallout blankets and proximal ignimbrites the eruption column is estimated to have reached ca 25 km and thus entered the stratosphere a late phase 5 vol is represented by trachyte emplaced chiefly as moderately welded ignimbrites the comendites contain 3 and the trachytes 10 20 vol phenocrysts mainly anorthoclase hedenbergite and fayalite primary glassy melt inclusions with no signs of leakage were found only in phenocrysts in the comenditic tephra whereas those in phenocrysts in the trachytes are devitrified the comendite magma is interpreted to have been generated by fractional crystallization from a trachyte magma represented by melt inclusions in the phenocrysts in the comendite tephra the mass of volatiles emitted to the atmosphere during the eruption was estimated using the petrologic method the average h2o concentration of the comenditic matrix glass is 1 5 wt probably largely secondary and of the corresponding melt inclusions 5 2 wt melt inclusions in feldspar and quartz present the highest halogen concentrations with a calculated average for chlorine of 4762 ppm and for fluorine of 4294 ppm the comenditic matrix glasses are represented by a fluorine rich 3992 ppm f and fluorine poor group 2431 ppm f averaging 3853 ppm for chlorine only 20 of all sulfur analyses of the comenditic matrix glasses and melt inclusions are above the detection limit of 250 ppm s the difference between pre and post eruptive concentration of h2o is at least 3 7 0 6 wt h2o taking into consideration re hydration of the matrix glass and possible leakage of melt inclusions the difference between pre and post eruptive concentrations of the halogens amounts to 909 90 ppm cl and 1863 280 ppm and 302 40 ppm f the difference for s was estimated based on the average of the maximum s concentrations in the melt inclusions 455 ppm s and the detection limit resulting in 205 40 ppm s the calculated mass of volatiles injected into the atmosphere based on the erupted magma volume and volatile data is 1796 453 megatons for h2o 45 10 megatons for chlorine 42 11 megatons for fluorine and 2 0 6 megatons for sulfur the 969 20 ad eruption of baitoushan volcano one of the largest eruptions of the past 2000 years is thought to have had a substantial but possibly short lived effect on climate

source model of the 2007 mw 8 0 pisco peru earthquake implications for seismogenic behavior of subduction megathrusts we use interferometric synthetic aperture radar teleseismic body waves tsunami waveforms recorded by tsunameters field observations of coastal uplift subsidence and runup to develop and test a refined model of the spatiotemporal history of slip during the mw 8 0 pisco earthquake of 15 august 2007 our preferred solution shows two distinct patches of high slip one patch is located near the epicenter while another larger patch ruptured 60 km further south at the latitude of the paracas peninsula slip on the second patch started 60 s after slip initiated on the first patch we observed a remarkable anticorrelation between the coseismic slip distribution and the aftershock distribution determined from the peruvian seismic network the proposed source model is compatible with regional runup measurements and open ocean tsunami records from the latter data set we identified the 12 min timing error of the tsunami forecast system as being due to a mislocation of the source caused by the use of only one tsunameter located in a nonoptimal azimuth the comparison of our source model with the tsunami observations validate that the rupture did not extend to the trench and confirms that the pisco event is not a tsunami earthquake despite its low apparent rupture velocity 1 5 km s we favor the interpretation that the earthquake consists of two subevents each with a conventional rupture velocity 2 4 km s the delay between the two subevents might reflect the time for the second shock to nucleate or alternatively the time it took for afterslip to increase the stress level on the second asperity to a level necessary for static triggering the source model predicts uplift offshore and subsidence on land with the pivot line following closely the coastline this pattern is consistent with our observation of very small vertical displacement along the shoreline when we visited the epicentral area in the days following the event this earthquake represents to our knowledge one of the best examples of a link between the geomorphology of the coastline and the pattern of surface deformation induced by large interplate ruptures

estimates of vertical crustal motion derived from differences of topex poseidon and tide gauge sea level measurements 1 we have computed estimates of the rate of vertical crustal motion from differences of sea level measurements made by the topex poseidon radar altimeter and a globally distributed network of 114 tide gauges a rigorous error analysis was performed which suggests the accuracy of the estimated vertical rates is approximately 1 2 mm year for roughly half of the tide gauges which is sufficiently accurate to detect a variety of geophysical phenomena while only a cursory analysis of the estimated crustal motion rates was performed we observed many interesting phenomena including significant uplift at volcanic islands in the pacific and uplift of 7 9 mm year along the southwest coast of alaska the results reported here will be useful in a variety of geophysical studies as well as for validation of similar estimates of vertical crustal motion provided by precise geodetic techniques such as slr doris gps and vlbi

composite nature of the north china granulite facies belt tectonothermal and geochronological constraints granulite facies rocks are intermittently exposed in a roughly e w trending belt that extends for approximately 2000 km across the north china craton from the helanshan qianlishan wulashan daqingshan guyang and jining complexes in the western block through the huai an hengshan xuanhua and chengde complexes in the trans north china orogen to the jianping western liaoning eastern hebei northern liaoning and southern jilin complexes in the eastern block the belt is generally referred to as the north china granulite facies belt previously interpreted as the lowest part of an obliquely exposed crust of the north china craton recent data indicate that the north china granulite facies belt is not a single terrane instead it represents components of three separate terranes the eastern and western blocks and trans north china orogen each of these units records different metamorphic histories and reflect the complex tectonic evolution of the ncc during the late archean and paleoproterozoic mafic granulites in the eastern block and the yinshan terrane western block underwent medium pressure granulite facies metamorphism at about 2 5 ga with anticlockwise p t paths involving near isobaric cooling following peak metamorphism reflecting an origin related to intrusion and underplating of mantle derived magmas pelitic granulites in the khondalite belt western block underwent medium pressure granulite facies metamorphism at about 2 0 1 9 ga with clockwise p t paths which record the paleoproterozoic amalgamation of the yinshan and ordos terranes to form the western block mafic and pelitic granulites in the trans north china orogen experienced high to medium pressure granulite facies metamorphism at 1 85 ga with clockwise p t paths involving nearly isothermal decompression following peak metamorphism which are in accord with the final collision between the eastern and western blocks to form the north china craton at 1 8 ga the ncgb cannot therefore represent a separate unique terrane instead it reflects the amalgamation of three separate granulite terranes that evolved independently and at different times d 2005 international association for gondwana research published by elsevier b v all rights reserved

late archean sm nd isochron age for mafic ultramafic supracrustal amphibolites from the northeastern sino korean craton china isotopic data published by previous workers document the presence of early archean 3 5 ga metabasaltic enclaves in grey gneisses west of bohai bay eastern hebei province p r c metabasaltic and metakomatiitic amphibolites crop out as lower supracrustal members of the archean section northeast of bohai bay in southern jilin eastern liaoning provinces six analyzed specimens of the latter unit contain more magnesium on analysis averaging approximately 13 vs 7 wt percent mgo but although they exhibit a wider range of ree concentrations they average a similar range of ree abundance patterns la lu 24 7x chondrite as the former 24 9 chondrite new sm nd isotopic and ree analyses combined with available petrologic geologic information indicate that metakomatiitic amphibolites from the sino korean craton northeast of bohai bay are late archean in emplacement age a wholerock sm nd isochron age of 2660 75 2 ma was obtained with nd t 4 4 0 5 as in many parts of the sino korean craton the highly positive nd t value suggests a prior extended history 1 0 ga of depletion of subcontinental mantle sources in some incompatible elements and in lree relative to hree a seventh analyzed sample a mafic inclusion in tonalitic gneiss of unknown age has an unusual chemical composition with strong enrichment in lree sr and zr and severe depletion in ni and cr judging from isotopic data which yield a much younger depleted mantle model age of 1 67 ga it could represent a cognate xenolith in a mid proterozoic tonalitic intrusion shown on present maps as archean in age the protolith might have been an evolved alkali basalt

folding of oceanic lithosphere folding of the lithosphere just south of the bay of bengal appears as 1 undulations in acoustic basement topography and 2 as linear geoid undulations in the seasat altimeter data from the seasat data we find that the east west trending folds have wavelengths ranging from 130 to 250 km and clustering about 190 km the horizontal gravity disturbances due to the folds range in amplitude from 15 to 50 mgal elastic models of oceanic lithosphere have in the past been used to demonstrate the implausibility of lithosphere buckling or folding in response to compression these elastic models typically predict that compressive stresses of about 5 gpa are required to buckle oceanic lithosphere with an age comparable to that of the northeastern indian ocean 40 70 ma these stresses exceed the strength of lithospheric rock we use an elastic plastic model to show that oceanic lithosphere of this age should have a net compressive strength equal to about 12 of the elastic buckling stress we further demonstrate that loads approaching the net compressive strength cause the lithosphere to fold with a wavelength about 200 km i e the wavelength observed from seasat our results reinforce earlier speculation that this folding may be related to the himalayan orogeny

investigations of fennoscandian glacial isostatic adjustment using modern sea level records we present a new method for determining the rates from a network of regional tide gauge data the method involves using a model for the sea level observations annual averages of relative sea level that explicitly includes a term for the interannual sealevel variations which are assumed to be constant for all sites in the network the resulting simultaneous analysis of all the sea level observations yields sea level rates which are biased by the unknown temporal slope of the interannual variations by differencing sea level rate estimates with respect to one site site referenced sea level rates are calculated which are free from this bias the differencing procedure also removes any signal due to a common sea level rate such as might be associated with eustatic sea level rise the resulting site referenced sea level rates therefore in principle reflect only the relative vertical crustal motions of the tide gauge sites with respect to the geoid these site referenced sea level rates represent a potentially more accurate data set than have previously been used for sea level studies we have used these rates to investigate glacial isostatic adjustment gia in fennoscandia specifically we have used the site referenced sea level rates within the baltic sea to estimate adjustments to the ice history and earth model which are used to calculate vertical rates of adjustment due to gia a method never before used for fennoscandia the parameters selected were lithospheric thickness the viscosities of assumed isoviscous upper and lower mantles and a fennoscandian ice thickness scaling parameter we present the results of this estimation procedure for a specific test ice model we also find evidence that the sea level record for the site nearest the center of uplift furuogrund may be contaminated by systematic errors of unknown origin data from this site have previously been used to determine a rate for the maximum uplift that we find is perhaps 1 mm yr 1 or 10 too large

effect of melting glaciers on the earth s rotation and gravitational field 1965 1984 summary yearly mass balance data for 85 glaciers in 13 of the 31 mountain glacier systems designated in meier s 1984 paper are averaged for the years 1965 1984 average rates of volume change for the 13 regions are compared to meier s 1984 estimates of glacial melting these data cover regions that account for about 74 per cent of the volume change estimated to have occurred in all the 31 mountain glacier systems from 1900 to 1984 the volume changes in the 13 regions tend to be less than those calculated by using changes in the volume of glaciers between 1900 and 1961 meier 1984 although the reason for this difference is not well known it could result from melting during the first half of the 20th century of ice accumulated during earlier periods or a decrease in the rise in atmospheric temperatures from 1945 to 1980 spatial and temporal empirical orthogonal functional analysis is used to bring out the similarities and differences among the 13 regions and identify those regions contributing most to the variance of the data set these regions are not necessarily those with the greatest average rates of volume change enough spatial variability is present to support the hypothesis that satellites may eventually be able to discern changes in the earth s glaciers through the gravitational field even though the signal from the mass change is small and changes in the gravitational field of the earth are contaminated with gravity signals from other mass changes on the earth s surface and interior zonal coefficients of the spherical harmonic expansion of the gravitational potential are calculated for yearly mass changes for these 13 regions up to i 8 there is little similarity at decadal periods between the polar motion excitation from mountain glacier systems and the observed excitation the majority of observed polar motion excitation could be due to other surface mass changes including continental water storage see for example chao 1988 the amplitude of the interannual excitation due to the glacial signal computed here is less than 10 per cent of the observed excitation and the secular trend of the excitation from melting glaciers in the 13 regions is about one quarter of that of the observed excitation yearly changes in the length of day lod are calculated from the glacial signals and compared to the observed yearly alod excess lod signal the contribution of glaciers to the total excess lod signal is less than one part in 150 of the observed signal as alod is caused mainly by core mantle coupling at decadal periods and atmospheric coupling at shorter periods the contributions to displacement of the centre of mass of the solid earth as seen by a satellite tracked from the earth s surface are calculated for the mountain glaciers and an 80 year record of global sea level for the glaciers the average displacements are as much as 1 mm over 20 years and for sea level the z coordinate of the average displacement is 5mm over its 80 year record interannual signals

newly imaged shape of the deep seismic zone within the subducting pacific plate beneath the hokkaido corner japan kurile arc arc junction 1 the geometry of the deep seismic zone associated with the subducting pacific plate beneath the north american plate in the hokkaido corner japan kurile arc arc junction has been investigated based on the hypocenters accurately relocated by a dense local seismographic network with three dimensional p and s wave velocity structures the model suggests that the lateral changes in the dip of the subduction zone are more rapid than previously believed we found that the deep seismic zone in the pacific plate dips at 20 to 30 on the side of the japan arc the dip angle increased in a narrow region around 143 144 e by 10 to 20 and the dip was 40 to 50 on the side of the kurile arc in the transitional zone around 143 144 e an unusual distribution of microearthquakes has been discovered within the pacific plate which was located on a near vertical plane with an area of 50 100 km2 with strike that was perpendicular to the kurile trench axis this feature was named the tokachi oki slab cracking zone we suggest that this is a slab cracking zone torn by the extensional stress due to the rapid lateral changes in the dip of the subduction zone the slab cracking zone may possibly grow into the large disruption or tear of the slab in the future

large scale coherence of sea level at very low frequencies abstract the coherence of sea level is examined between a number of widely distributed stations chosen from those with the longest datasets such as at san francisco where the data has been recorded since 1855 the sea level signals in the eastern pacific appear to be dominated by propagating rossby waves so that the variability which has periods of 5 8 years e g between san francisco and honolulu is coherent but out of phase by several years a surprising finding is that sea level is coherent on opposite sides of the atlantic at periods near 6 years but this is suspected to be the result of direct atmospheric forcing rather than of wave propagation at the longest periods detectable 40 50 years the sea level signals have amplitudes of 5 15 cm and are visually coherent between the west coasts of the united states and europe the amplitude of these extremely long period signals is the same as the apparent rise of sea level over the the past century although the rate of rise from these fluct

steric sea level variations during 1957 1994 importance of salinity 1 spatially averaged 50 s 65 n temperature and salinity changes in the 0 3000 m layer during the 1957 1994 period resulted in a sea level rise at a mean rate of about 0 55 mm per year about 10 of this rate is due to a decrease of the volume mean salinity the magnitude of total steric sea level tssl changes and the ratio of thermosteric and halosteric anomalies to tssl anomaly are nonuniform geographically salinity effects are critically important to the tssl changes in some regions of the ocean for example the thermosteric anomaly is nearly compensated by the halosteric anomaly in the subpolar north atlantic this fact will cause erroneous heat content estimates based on altimetric observations from space if a climatological salinity is assumed based on the present historical archive of salinity data a decrease in global mean salinity has occurred this increase of fresh water would cause sea level rise at a rate of 1 3 0 5 mm yr if the added water comes from sources other than floating sea ice

space geodetic constraints on glacial isostatic adjustment in fennoscandia analysis of global positioning system gps data demonstrates that ongoing three dimensional crustal deformation in fennoscandia is dominated by glacial isostatic adjustment our comparison of these gps observations with numerical predictions yields an earth model that satis es independent geologic constraints and bounds both the average viscosity in the upper mantle 5 x 10 20 to 1 x 10 21 pascal seconds and the elastic thickness of the lithosphere 90 to 170 kilometers we combined gps derived radial motions with fennoscandian tide gauge records to estimate a regional sea surface rise of 2 1 0 3 mm year furthermore ongoing horizontal tectonic motions greater than 1 mm year are ruled out on the basis of the gps derived three dimensional crustal velocity field

statistical simulation of wave climate and extreme beach erosion abstract recent developments in extreme values modelling have been used to develop a framework for determining the coastal erosion hazard on sandy coastlines this framework quantitatively reproduced the extreme beach erosion volumes obtained from field measurements at narrabeen beach australia this encouraging finding was achieved using kriebel and dean s kriebel d l and dean r g 1993 convolution method for time dependent beach profile response journal of waterway port coastal and ocean engineering 119 2 204 226 simple beach erosion and accretion model the method includes allowances for joint probability between all basic erosion variates including wave height period and direction event duration tidal anomalies and event spacing a new formulation for the dependency between wave height and period has been developed it includes the physical wave steepness limitation event grouping where significantly more erosion can occur from two closely spaced storms is handled by temporally simulating the synthetic wave climate and the resulting beach erosion and accretion

fast cooling following a late triassic metamorphic and magmatic pulse implications for the tectonic evolution of the korean collision belt we discuss the evolution of korea in the context of a relatively short lived tectonically induced magmatic and metamorphic pulse that affected large portions of the crust of the peninsula s southern part during the late triassic recent 40ar 39ar single grain laser step heating dates imply a prolonged metamorphic recrystallization between 243 and 220 ma which occurred in distinct phases that were not coeval throughout the peninsula we obtained identical plateau ages between 231 4 0 8 and 228 9 0 8 ma 1 85 95 39ar release on single grains of detrital muscovite from jurassic sandstones gimpo group a literature review shows that the ages of detrital muscovites are identical to 1 concordant 40ar 39ar ages of biotite 228 ma and amphibole 230 ma in amphibolites of the deokjeongri gneiss formation and the weolhyeonri complex pointing to very rapid cooling of 100 150 c ma and 2 231 229 ma muscovite from the low grade metamorphic mid paleozoic turbidites of the taean formation the efficiency of cooling is further underlined by the near coincidence of these 40ar 39ar ages with 243 229 ma average 234 6 ma zircon u pb ages in the gyeonggi massif and the hongseong belt in the literature it is argued that the late triassic magmatic and metamorphic pulse is superimposed on an earlier tectono metamorphic event possibly related to collision indicated by 1 243 237 ma muscovite ages or age components in age spectra and 2 two generations of folds and associated tectonic foliations truncated by 229 5 ma old syenites and earlier mafic dykes the late triassic thermal pulse could have been the result of post collisional delamination of the lower crust and uppermost mantle and or oceanic slab break off which is also suggested by almost coeval widespread mantle sourced mg rich potassic magmatism continuing ductile deformation is shown by mylonitization of late triassic magmatic rocks an 220 ma muscovite age may be related to this

land motion estimates from gps at tide gauges a geophysical evaluation summary space geodesy applications have mainly been limited to horizontal deformations due to a number of restrictions on the vertical component accuracy monitoring vertical land motion is nonetheless of crucial interest in observations of long term sea level change or postglacial rebound measurements here we present a global vertical velocity field obtained with more than 200 permanent gps stations most of them colocated with tide gauges tgs we used a state of the art homogeneous processing strategy to ensure that the reference frame was stable throughout the observation period of almost 10 yr we associate realistic uncertainties to our vertical rates taking into account the time correlation noise in the time series the results are compared with two independent geophysical vertical velocity fields 1 vertical velocity estimates using long term tg records and 2 postglacial model predictions from the ice 5g vm2 adjustment the quantitative agreement of the gps vertical velocities with the internal estimates of vertical displacements using the tg record is very good with a mean difference of 0 13 1 64 mm yr 1 on more than 100 sites for 84 per cent of the gps stations considered the vertical velocity is confirmed by the tg estimate to within 2 mm yr 1 the overall agreement with the glacial isostatic adjustment gia model is good with discrepancy patterns related either to a local misfit of the model or to active tectonics for 72 per cent of the sites considered the predictions of the gia model agree with the gps results to within two standard deviations most of the gps velocities showing discrepancies with respect to the predictions of the gia model are however consistent with previously published space geodesy results we in turn confirm the value of 1 8 0 5 mm yr 1 for the 20th century average global sea level rise and conclude that gps is now a robust tool for vertical land motion monitoring which is accurate at least at 1 mm yr 1

earthquakes and relative sealevel changes 1 using a spherical model of postseismic deformation for the first time we have computed the global contribution of large earthquakes to the relative sealevel variations in the twentieth century we have found that great earthquakes have the overall tendency to produce a sealevel rise and that they affect the measurements taken at those tide gauge sites that are commonly employed to obtain global estimates of sealevel rise though on a global scale most of the signal is associated with thrust events on a regional scale the effects of great transcurrent earthquakes cannot be neglected depending on the viscosity of the asthenosphere the contribution of earthquakes to the long term sealevel changes amounts to at least 0 1 mm yr thus the climate driven long term sealevel changes deduced by tide gauge observations may be slightly but not negligibly overestimated

fore arc structure and plate boundary earthquake sources along the southwestern kuril subduction zone 1 the geologic structure and gravity anomalies of the fore arc wedge along the southwestern kuril arc were compared with the sources of seismic waves and tsunamis of the 1952 1973 and 2003 plate boundary earthquakes the source areas are generally located beneath fore arc basins in the upper slope which has been subsiding except for the tsunami source of the 1952 earthquake while the slip amount varies beneath the basins large slip of seismic sources of the 1952 and 2003 earthquakes occurred under the low gravity anomaly zone of a fore arc basin and a structural ridge along the n s oriented collision zone between the kuril and ne japan fore arcs where there is inferred to be a zone of a strong basal erosion of the overriding plate the tsunami sources are located under the subsiding area to the east of the collision zone these comparisons indicate that the source areas are primarily restricted to the region under the subsiding area of the upper slope and the lateral change of slip amount in the source areas is related to the collision tectonics of the fore arc sliver the 1952 tsunami source extended seaward which was presumably induced by the slip of the larger seismic source under the upper slope the lack of large scale slope failure or splay faults in the middle to lower slope suggests that the slip along the plate boundary is responsible for tsunami generation a subducting seamount presumably prevented the seaward propagation of the rupture beneath the middle to lower slope

using global positioning system derived crustal velocities to estimate rates of absolute sea level change from north american tide gauge records 1 we identified 37 tide gauges each located within 40 km of a geodetic station whose international terrestrial reference frame of 2000 itrf2000 crustal velocity had been rigorously derived from continuous global positioning system gps observations spanning from 3 to 11 years the tide gauges are located along the coasts of north america bermuda hawaii and kwajalein in the marshall islands we obtained the itrf2000 crustal velocities by averaging values from six solutions each produced by a team of investigators acting essentially independently of the other teams we then applied crustal velocities to convert rates of relative sea level change to rates of absolute sea level change in a sample containing 30 sites we found that the mean rate of absolute sea level change equals 1 80 0 18 mm yr in the 1900 1999 period the scatter about the mean for individual sites in this sample is characterized by a weighted rms value of 0 85 mm yr this scatter primarily reflects the uncertainty associated with derived crustal velocities the remaining seven sites i e five sites on the pacific coast of alaska one on dauphin island alabama and one on kwajalein an atoll in the pacific ocean experienced relatively low rates of absolute sea level change we hypothesize the low rates in alaska are caused by ongoing melting of mountain glaciers and ice masses near the stations while the low rates found for dauphin island and kwajalein remain unexplained

the application of zircon cathodoluminescence imaging th u pb chemistry and u pb ages in interpreting discrete magmatic and high grade metamorphic events in the north china craton at the archean proterozoic boundary abstract two distinct late neoarchean to early paleoproterozoic magmatic events are recognized at the northern margin of the eastern block of the north china craton based on interpretation of zircon structure cathodoluminescence signature th u pb chemistry and age the first event is represented by emplacement of the chaihe trondhjemite and xianjinchang tonalite with magmatic zircon core ages ranging from 2559 2553 7 ma respectively these rocks experienced a subsequent high grade metamorphic event constrained by partial recrystallization of primary magmatic zircon and growth of new zircon rims between 2517 and 2490 ma a second magmatic episode generated by partial melting of crustal rocks during this metamorphic event is represented by the hongshilazi syenogranite with an age of 2502 11 ma the short time interval between initial magmatism and high grade regional metamorphism signifies they were related to the same major tectonothermal event when considered along with evidence of a similar sequence of events at this time 800 km to the south in eastern hebei and the previously established 2500 ma age of granulite facies metamorphism in mafic rocks across the craton it is proposed that a large mantle plume developed beneath the north china craton at the close of the archean

spectroscopic analysis of global tide gauge sea level data summary yearly and monthly tide gauge sea level data from around the globe are fitted to numerically generated tidal data to search for the 18 6 yr lunar nodal tide and 14 month pole tide both tides are clearly evident in the results with amplitudes and phases that are consistent with a global equilibrium response global atmospheric pressure data are fitted to global monthly sea level data to study the response of the ocean to pressure fluctuations the global response of sea level to pressure is found to be inverted barometer at periods greater than 2 months a large coherence at 437 days between pressure and sea level data is found for the north sea baltic sea and the gulf of bothnia the results are not entirely conclusive but they tend to support o connor s 1986 suggestion that the apparent enhanced pole tide in these basins may be due to meteorological forcing rather than to a basin scale resonance finally global averages of tide gauge data after correcting for the effects of post glacial rebound on individual station records reveal an increase in sea level over the last 80 yr of between 1 1 and 1 9 mm yr as part of the process of removing the effects of post glacial rebound we fit those effects to the global tide gauge data and obtain very good agreement with results predicted from post glacial rebound models this tends to support the post glacial model results and it suggests that the global tide gauge data are indeed capable of resolving changes in sea level at the mm yr level

a tribute to george plafker abstract in a long and distinguished career george plafker made fundamental advances in understanding of megathrust tectonics tsunami generation paleoseismology crustal neotectonics and alaskan geology chiefly by means of geological field observations george discovered that giant earthquakes result from tens of meters of seismic slip on subduction megathrusts and he did this before the theory of plate tectonics had become a paradigm the discovery was founded on george s comprehensive mapping of land level changes in the aftermath of the 1964 earthquake in alaska and on his follow up mapping in 1968 in the region of the 1960 earthquakes in chile the mapping showed paired parallel belts of coseismic uplift largely offshore and coseismic subsidence mostly onshore a pattern now familiar as the initial condition assumed in simulations of subduction zone tsunamis george recognized moreover that splay faulting can play a major role in tsunami generation and he also distinguished carefully between tectonic and landslide sources for the multiple tsunamis that accounted for nearly all the fatalities associated with the 1964 alaska earthquake george s classic monographs on the 1964 earthquake include findings on subduction zone paleoseismology that he soon extended to include stratigraphic evidence for cyclic vertical deformation at the copper river delta as well as recurrent uplift evidenced by flights of marine terraces at middleton island as a geologist of earthquakes george also clarified the tectonics and hazards of crustal faulting in alaska california and other areas worldwide all the while george was mapping bedrock geology in alaska where he contributed importantly to today s understanding of how terranes were accreted and modified especially important was his documentation of the origin movement subduction and collision of the yakutat terrane in southern alaska

southeastern caribbean sea level variability and viscoelastic relaxation viscoelastic modeling of earthquakes in the southeast caribbean shows that distant dip slip earthquakes in the lesser antilles and the geometry of the subduction zone play a significant role in vertical deformation observed along the southern caribbean plate margin we find that dip slip earthquakes yield vertical displacements that are 1 2 orders of magnitude greater than those generated by strike slip earthquakes along the caribbean south american plate boundary in addition postseismic vertical displacements are at least as great or greater at distances of several hundred kilometers than the coseismic counterpart depending upon the geometry of the source tide gage data from venezuela suggest that these vertical displacement rates may still be observed several decades after the occurrence of large subduction zone earthquakes ms 7 or greater in addition the uplift rate observed at the tide gages largely follows the anticipated flexure of the caribbean plate due to the subduction process

recurrence of postseismic coastal uplift kuril subduction zone japan 1 coastal stratigraphy of eastern hokkaido indicates that decimeters of coastal uplift occurred repeatedly in the late holocene employing radiocarbon dating and tephrochronology we identify along a 100 km length of the kuril subduction zone six uplift events since 2 800 years b p uplift events occur at the same frequency as unusually high tsunamis each coastal uplift event which occurs on average every 500 years is the product of decade long post seismic deep slip on the down dip extension of the seismogenic plate boundary following an offshore multi segment earthquake that generates unusually high tsunamis

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

crustal development of the hida belt japan evidence from nd sr isotopic and chemical characteristics of igneous and metamorphic rocks abstract chemical and sr nd isotopic investigations were performed on the igneous and metamorphic rocks in the hida belt central japan to clarify their ages and possible sources and to provide constraints on the crustal evolution of the eastern margin of the asian continent igneous rocks of three main stages in the hida belt represented by the late silurian amphibolites first stage the middle carboniferous mafic dikes second stage and the late triassic to early jurassic granite gabbro plutons third stage show alkaline to calc alkaline chemical affinity major and trace element characteristics show that the three stages of igneous rocks were emplaced in a continental margin or continental arc environment the mafic igneous rock suites have relatively high e nd 0 5 to 5 5 and low 87 sr 86 sr 0 7049 to 0 7061 values indicating their origin from upper mantle sources though the third stage granitoids contain recycled crustal components the hida gneisses of clastic origin show two groups of model ages t dm middle proterozoic 1 4 2 2 ga and late proterozoic to early paleozoic 0 55 0 74 ga consistent with geological geochemical and radiometric age data are that the sedimentation and basaltic volcanism occurred in early to middle paleozoic and the protoliths with middle proterozoic model ages are detritals from the proterozoic continental provenances a synthesis of available geological and geochemical data for the basement metamorphic and igneous rocks in eastern asia suggests two possibilities for the paleozoic to early mesozoic history of the hida belt 1 the hida belt was formed at the eastern margin of the north china block with later evolution as a suture zone between the north and south china blocks or 2 it evolved as a part of the east central asian orogenic belt ecaob to the north

neoarchean to paleoproterozoic continental evolution and tectonic history of the north china craton a review rocks of archean age are widely distributed in the north china craton ncc and can be divided into high grade regions and granite greenstone belts even though most underwent amphibolite to granulite facies metamorphism quartzo feldspathic gneisses occupy 70 to 85 of the total exposure of archean rocks in the craton supracrustal rocks commonly consist of intercalated volcano sedimentary rocks including metabasites meta intermediate to acid rocks banded iron formations metapelites and minor marbles the oldest rocks outcrop over a small area of 4 km2 and are a quartzite amphibolite sequence that yield 3 8 3 5 ga isotopic ages chemical and geochronological data constrain the earliest main crust forming episode at ca 2 9 2 7 ga when most rocks were metamorphosed to upper amphibolite or granulite facies at moderate pressures mafic granulites can be classified into two textural types referred to as near isobaric cooling ibc and near isothermal decompression itd types high pressure granulites and retrograded eclogites occur mainly near the junction of the provinces of hebei shanxi and inner mongolia in the central ncc and in eastern shandong province of the eastern ncc as well as locally in henan province in the southern ncc these high pressure rocks show clockwise p t paths indicating decompression from 14 kb to 5 6 kb an exposed section interpreted as representing precambrian continental lower crust has also been identified in the northern part of the craton although some mafic ultramafic metamorphic rocks have been interpreted as remnants of ancient oceanic crust and mantle by a number of geologists geochemical and petrological evidence demonstrates that many supracrustal orthogneiss associations have island arc affinities therefore several tectonic models have been proposed including continent continent collision and island arc terrain accretion achieved by arc arc or arc microcontinent collision the ncc underwent multiple high grade metamorphic events of which the two most important took place during the intervals 2600 2450 ma and 1950 1750 ma which are considered to be related to early precambrian supercontinental cycles

new uranium series ages of the waimanalo limestone oahu hawaii implications for sea level during the last interglacial period abstract the waimanalo formation limestone of oahu has been correlated with the last interglacial period based on u series dating of corals by t l ku and colleagues the limestone consists of growth position corals and overlying coral conglomerate an apparent bimodal distribution of ages for the growth position corals mean age 133 ka and the overlying coral conglomerate mean age 119 ka has been interpreted to represent two distinct high stands of sea that occurred within the last interglacial period both growth position corals and overlying conglomerate coral occur in an outcrop east of kaena point and consist mainly of pocillopora and porites u series ages of growth position corals that show closed system conditions are 120 3 ka and 127 4 ka overlying conglomerate corals have u series ages that range from 120 3 ka to 138 4 ka at kahe point conglomerate corals have ages of 120 3 ka and 134 4 ka these data show that the growth position corals are not systematically older than the conglomerate corals thus there is no evidence for two distinct high stands of sea waimanalo deposits at kahe point and mokapu point new u series ages of 134 4 ka and 127 3 ka have beach deposits as high as 12 5 m and at mokapu point growth position corals as high as 8 5 m a last interglacial sea level stand of 8 5 to 12 5 m conflicts with estimates of 6 m from a number of tectonically stable coastlines and islands in the western atlantic ocean we infer therefore that oahu may be undergoing uplift at a low rate this uplift may be due to compensatory lithospheric flexure because the island of hawaii has been subsiding throughout much of the quaternary from volcanic loading because of this possible uplift oahu and islands like it elsewhere in the pacific cannot be used as reference points for sea level during the last interglacial period

a review of the trends observed in british isles mean sea level data measured by tide gauges summary this report presents an up to date review of the british isles bi mean sea level msl data set obtained from tide gauges and of the long term secular trends in bi msl the data are of mixed quality and not as copious as one would like for scientific analysis given the complexity of long term sea and land level changes around bi coasts nevertheless the small number of very long records can be studied evectively and indicate that twentieth century secular trends in bi msl are consistent with those obtained from nw europe as a whole and with the bottom range of estimates for global average msl change during the past 100 years century timescale low frequency accelerations in msl of the order of 0 4 0 8 mm yr 1 century 1 are obtained from the three longest records which are also similar to estimates from mainland europe sea level indices for the bi are constructed which can provide responsible agencies with a guide to the average state of bi sea level combined ocean tide and storm surge tide surge numerical modelling is demonstrated to be a valuable tool in understanding part of the variability of msl around the bi although modelling of long term changes is limited at present by the lack of adequate meteorological data sets from before 1955 nevertheless it is shown that even if a complete meteorological modelling data set were available it would not be able to account for all of the msl variability finally recommendations are made for the development of tide gauge and global positioning system gps recording in the bi for the purpose of long term msl monitoring in the next century

vertical crustal movements along the east coast north america from historic and late holocene sea level data abstract sea level data from eastern north america are analyzed for evidence of neotectonism which is inferred from residual sea level anomalies after removal of glacial isostatic and eustatic components the sea level is examined on two different time scales using long term holocene paleosealevel indicators and short term 100 yrs tide gauge records the major process affecting holocene sea levels in this region is the continuing response to glacial unloading the northward migration of the collapsed bulge peripheral to the retreating ice sheets is clearly delineated by the displacement of the hingeline between glacioisostatic subsidence and uplift from around 43 to 48 n over the last 14 000 years similarly the zone of maximal subsidence collapsed forebulge has moved from 36 42 n prior to 11 000 years to 44 46 n during the last 5000 years tide gauge data for the east coast covering the last 100 years indicate a sea level rise of around 2 4 mm yr subtraction of the late holocene trend reduces the regional mean from 2 72 0 71 mm yr to 1 26 0 78 mm yr which is close to the value 1 47 0 68 mm yr obtained by using viscoelastic model corrections after peltier 1986 thus nearly half of the recent regional sea level rise appears to be of glacioisostatic origin the corrected mean regional trend lies within a few tenths of a mm yr of the estimated mean global eustatic trend 1 1 mm yr gornitz and lebedeff 1987 generally the results show no evidence for major tectonic movements especially for large fault offsets nevertheless several anomalous areas persist that are suggestive of gentle warping after glacioisostatic and eustatic processes have been taken into account these correspond to areas with known neogene epeirogenic movements and include the region between savannah georgia charleston south carolina subsidence cape fear arch uplift southern chesapeake bay late pleistocene holocene uplift succeeded by recent subsidence montauk and the long island platform uplift subsidence in the charleston area and southern chesapeake bay may be in part caused by groundwater withdrawal

secular and earthquake related vertical crustal movements in japan as deduced from tidal records 1951 1981 abstract monthly tidal records for the last 31 years from about 100 tidal stations are used to delineate vertical crustal movements in japan a new computer aided processing system was created for this purpose its principle is differential use of tidal records in a region so that the oceanographic disturbances of common causes may be eliminated from the sea level data this method enables us to observe nearly absolute vertical land movement at tidal stations with a precision of a few centimeters the japanese islands are divided into nine regions taking oceanographic conditions into account general discussion on recent vertical movements has yielded several notable features and trends as follows 1 1 rapid and stationary subsidence in the northeastern part of japan presumably of tectonic origin 2 2 a complex pattern of uplift and subsidence in the southwestern part of japan which seems to reflect subduction of the philippine sea plate against the honshu block 3 3 relatively stable land on the japan sea side of honshu movements related to the earthquakes during the period 1951 1981 are also discussed although few of the cases show clear cut premonitory movements if abnormal movements in a coastal area appeared with an amplitude exceeding 2 or 3 cm we could detect them by the present system

late quaternary environments in ruby valley nevada abstract palynological data from sediment cores from the ruby marshes provide a record of environmental and climatic changes over the last 40 000 yr the modern marsh waters are fresh but no deeper than 3 m a shallow saline lake occupied this basin during the middle wisconsin followed by fresh and perhaps deep waters by 18 000 to 15 000 yr b p no sediments were recovered for the period between 15 000 and 11 000 yr b p possibly due to lake desiccation by 10 800 yr b p a fresh water lake was again present and deeper than modern conditions lasted until 6800 yr b p the middle holocene was characterized by very shallow water and perhaps complete desiccation the marsh system deepened after 4700 yr b p and fresh water conditions persisted until modern times vegetation changes in ruby valley were more gradual than those seen in the paleolimno logical record sagebrush steppe was more widespread than at present through the late pleistocene and early holocene giving way somewhat to expanded shadscale vegetation between 8500 and 6800 yr b p shadscale steppe contracted by 4000 yr b p but had greater than modern coverage until 1000 to 500 yr ago pinyon juniper woodland was established in the southern ruby mountains by 4700 yr b p

evidence of giant earthquakes and tsunamis of the seventeenth century type along the southern kuril subduction zone eastern hokkaido northern japan a review

episodic emergence in the past 3000 years at the akkeshi estuary hokkaido northern japan at the akkeshi estuary rapid emergence interrupted holocene submergence at least four times in the past 3000 years each emergence event produced an upward change from estuarine mud to freshwater peat while the estuarine mud abounds in brackish and marine diatoms freshwater taxa dominate the peat emergence events occurred from 1700 to 2300 1000 to 1300 and 500 to 700 cal yr b p an additional emergence event predated by several decades a volcanic ash that erupted in a d 1694 at least three of the events produced contacts abrupt enough to represent uplift during earthquakes such uplift may reconcile seemingly conflicting records of vertical crustal movement in eastern hokkaido this tectonically active area which is being subducted by the pacific plate at 8 cm yr contains marine terraces that imply 0 1 0 5 mm yr of net uplift in the late quaternary however these terraces adjoin tide gages that recorded 8 9 mm yr of steady submergence in the 20th century the terrace uplift need not conflict with the gaged submergence if the region is subject to occasional coseismic uplift as during the emergence events implied by holocene geology near akkeshi

late mid holocene sea level oscillation a possible cause abstract sea level oscillated between 5500 and 3500 years ago at murrells inlet south carolina chezzetcook and baie verte nova scotia and montmagny quebec the oscillation is well constrained by foraminiferal marsh zonations in three locations and by diatoms in the fourth one the implications are 1 there was a eustatic sea level oscillation of about 2 10 m in the late mid holocene on the southeast coast of north america south carolina to quebec that is not predicted by present geophysical models of relative sea level change 2 this oscillation coincides with oceanographic cooling on the east coast of canada that we associate with melting ice and 3 this sea level oscillation climatic event coincides exactly with the end of pyramid building in egypt which is suggested to have resulted from a climate change i e drought cooling this sea level climatic change is a prime example of feedback where climatic warming in the mid holocene promoted ice melt in the arctic which subsequently caused climatic cooling by opening up arctic channels releasing cold water into the inner labrador current that continued to intensify until 4000 years ago this sea level event may also be the best way of measuring when the final ice melted since most estimates of the ages of the last melting are based on end moraine dates in the arctic which may not coincide with when the last ice actually melted out since there is no way of dating the final ice positions

thermal evolution of two textural types of mafic granulites in the north china craton evidence for both mantle plume and collisional tectonics mafic granulites from the north china craton can be divided into two textural types referred to as a and b types a type mafic granulites display garnet quartz symplectic coronas and outcrop in the eastern and western zones of the craton whereas b type mafic granulites exhibit orthopyroxene plagioclase clinopyroxene symplectites or coronas and are mainly exposed in the central zone of the craton most a type mafic granulites preserve the prograde m 1 peak m 2 and post peak near isobaric cooling m 3 assemblages which are represented respectively by inclusions of hornblende plagioclase quartz a peak mineralogy of orthopyroxene clinopyroxene plagio clase quartz garnet and overprinted by garnet quartz symplectic coronas these mineral assem blages and their p t pressure temperature estimates define anticlockwise p t evolutionary paths the b type mafic granulites preserve the peak m 1 post peak near isothermal decompression m 2 and cooling m 3 assemblages which are represented by the peak assemblage of orthopyroxene clinopyroxene plagioclase quartz garnet hornblende post peak orthopyroxene plagioclase clinopyroxene symplectites or coronas and later hornblende plagioclase magnetite symplectites respectively these mineral assemblages and their p t estimates define clockwise p t paths the anticlockwise p t paths of the a type mafic granulites in the eastern and western zones of the north china craton are consistent with a model of underplating and intrusion of mantle derived magmas in combination with lithological structural and geochronological data the eastern and west ern zones of the north china craton are considered to represent two continental blocks that devel oped through the interaction of mantle plumes with the lithosphere from the palaeoarchaean to the neoarchaean era the b type mafic granulites and associated rocks in the central zone represent a magmatic arc that was metamorphosed and deformed during amalgamation of the eastern and west ern continental blocks in the late palaeoproterozoic era the mineral reaction relations and clockwise p t paths of the b type mafic granulites from the central zone record the tectonothermal history of the collision that resulted in the final assembly of the north china craton at c 1800 ma

coseismic slip and early afterslip of the 2015 illapel chile earthquake implications for frictional heterogeneity and coastal uplift great subduction earthquakes are thought to rupture portions of the megathrust where interseismic coupling is high and velocity weakening frictional behavior is dominant releasing elastic deformation accrued over a seismic cycle conversely postseismic afterslip is assumed to occur primarily in regions of velocity strengthening frictional characteristics that may correlate with lower interseismic coupling however it remains unclear if fixed frictional properties of the subduction interface coseismic or aftershock induced stress redistribution or other factors control the spatial distribution of afterslip here we use interferometric synthetic aperture radar and global position system observations to map the distribution of coseismic slip of the 2015 mw 8 3 illapel chile earthquake and afterslip within the first 38 days following the earthquake we find that afterslip overlaps the coseismic slip area and propagates along strike into regions of both high and moderate interseismic coupling the significance of these observations however is tempered by the limited resolution of geodetic inversions for both slip and coupling additional afterslip imaged deeper on the fault surface bounds a discrete region of deep coseismic slip and both contribute to net uplift of the chilean coastal cordillera a simple partitioning of the subduction interface into regions of fixed frictional properties cannot reconcile our geodetic observations instead stress heterogeneities either preexisting or induced by the earthquake likely provide the primary control on the afterslip distribution for this subduction zone earthquake we also explore the occurrence of coseismic and postseismic coastal uplift in this sequence and its implications for recent hypotheses concerning the source of permanent coastal uplift along subduction zones

aperiodic recurrence of geologically recorded tsunamis during the past 5500 years in eastern hokkaido japan 1 along hokkaido s pacific coast near the town of kiritappu sandy deposits in a muddy lagoon and on a nearby beach ridge plain provide evidence for 15 tsunamis between 200 and 6000 years ago additional sand beds at the lagoon probably represent the historical tsunamis of a d 1843 and 1894 we observed the sequences of sandy deposits in continuous slices 2 to 4 m deep some of the deposits consist of just a single sand bed whereas others contain multiple units of sand muddy sand or sandy mud and mud caps including plant detritus we also found at the lagoon a 17th century tsunami deposit that thickens and thins regardless of elevation or distance inland we bracketed the ages of most of the inferred tsunamis by radiocarbon dating of detritus mainly seeds and leaves at the lagoon and charcoal at the beach ridge plain from pretsunami and posttsunami beds tsunami dates computed from the bracketing ages commonly have uncertainties spanning 2 to 4 centuries within these uncertainties the inferred sequence of 15 prehistoric tsunamis at the lagoon beginning almost 6000 years ago can be matched tsunami by tsunami with the inferred history at the beach ridge plain 15 km away the sand sheet extents suggest that most of these tsunamis were larger than any generated at hokkaido in the last 200 years the intervals between these inferred outsized tsunamis average nearly 400 years but range widely from about 100 to about 800 years

bed shear stress estimation on an open intertidal flat using in situ measurements abstract accurate estimations for the bed shear stress are essential to predict the erosion and deposition processes in estuaries and coasts this study used high frequency in situ measurements of water depths and near bed velocities to estimate bed shear stress on an open intertidal flat in the yangtze delta china to determine the current induced bed shear stress c the in situ near bed velocities were first decomposed from the turbulent velocity into separate wave orbital velocities using two approaches a moving average ma and energy spectrum analysis esa c was then calculated and evaluated using the log profile lp turbulent kinetic energy tke modified tke tkew reynolds stress rs and inertial dissipation id methods wave induced bed shear stress w was estimated using classic linear wave theory the total bed shear stress cw was determined based on the grant madsen wave current interaction model wci the results demonstrate that when the ratio of significant wave height to water depth hs h is greater than 0 25 cw is significantly overestimated because the vertical velocity fluctuations are contaminated by the surface waves generated by high winds in addition wind enhances the total bed shear stress as a result of the increases in both w and c generated by the greater wave height and reinforcing of vertical turbulence respectively from a comparison of these various methods the tkew method associated with esa decomposition was found to be the best approach because 1 this method generates the highest mean index of agreement 2 it uses vertical velocities that are less affected by doppler noise and 3 it is less sensitive to the near bed stratification structure and uncertainty in bed location and roughness

fluctuations in relative sea level during the past 3000 yr in the onnetoh estuary hokkaido northern japan this paper presents the results of a litho bio and chronostratigraphical study of the evidence for late holocene sea level change palaeoseismicity and coastal evolution at the onnetoh estuary northwest japan alternating peat and mud couplets record evidence for four falls in relative sea level since ca 2500 cal yr bp in the latest instance intertidal mud with a salt tolerant diatom and plant macrofossil flora is abruptly overlain by a freshwater peat containing abundant macrofossil remains of the conifer picea glehnii these stratigraphical changes record an abrupt change from tidal flat to upland with no intermediate transition through saltmarsh in the other three instances the stratigraphy records a more gradual fall in relative sea level as shown by gradational stratigraphical contacts and transitional diatom and plant macrofossil assemblages once established these freshwater peat communities are gradually submerged and become overlain by saltmarsh and then intertidal muds radiocarbon ages and tephra date the emergence events to 2700 1750 gradual 1350 950 gradual 650 300 gradual and ca 400 cal yr bp abrupt these ages are similar to a sequence of emergence events recorded at the akkeshi estuary 70 km to the west of the present study site the three falls in relative sea level may record coseismic or swift post seismic uplift caused by plate boundary subduction earthquakes on the kurile subduction zone the oldest relative sea level fall is correlated with the so called yayoi regression dated to 1500 3000 cal yr bp in other parts of japan copyright 2002 john wiley sons ltd

ice 3g a new global model of late pleistocene deglaciation based upon geophysical predictions of post glacial relative sea level change a new high resolution global model of late pleistocene deglaciation is inferred on the basis of geophysical predictions of postglacial relative sea level variations in which the ice ocean solid earth interaction is treated in a gravitationally self consistent fashion for the purpose of these analyses the radial viscoelastic structure of the planet is assumed known on the basis of previously published sensitivity tests on solutions of the forward problem only radiocarbon controlled relative sea level histories from sites that were actually ice covered with one or two additions are employed to constrain the model leaving relative sea level rsl data from sites that were not ice covered to be employed to confirm its consistency results for these confirmatory analyses are reported elsewhere here the new deglaciation model referred to as ice 3g is compared to previous models derived by several independent means and tested against a number of additional observations other than sea level histories including geologically controlled retreat isochrones oxygen isotope data from deep sea sedimentary cores and coral terrace elevations the latter two observations strongly constrain the net sea level rise that has occurred since the onset of deglaciation and therefore the mass of ice that melted during the last glacial interglacial transition

p and s wave velocity model along crustal scale refraction and wide angle reflection profile in the southern korean peninsula abstract the onshore seismic experiment kcrt2004 explored the crustal velocity structure of the southern korean peninsula we present an interpretation of seismic data along this 340 km long nnw sse trending profile the crust was found to consist of three layers the upper middle and lower crust with p and s wave velocities ranging 5 50 to 6 95 km s and 2 82 to 3 91 km s respectively the average p wave velocity 6 26 km s and pn velocity 7 82 7 88 km s are lower than the worldwide average of continental crust moho depths are 29 0 34 9 km gradually thickening toward south the vp vs ratio of crustal material is estimated to be 1 73 0 249 for the upper and middle crust and the ratio increases with the depth in the lower crust the gyeonggi massif in the north of the profile has a lower vp vs ratio than other tectonic units the average crustal vp vs ratio of 1 74 0 253 is remarkably lower than the average value 1 78 0 27 for the bulk continental crust the low average crustal vp vs ratio is similar to that measured in eastern china the empirical analysis using both p wave velocity and vp vs ratio shows that the upper and middle crust is dominantly felsic and the lower crust is intermediate in composition the absence of the mafic material in the lower crust that is also found in eastern china contrasts with the generally accepted global model of the mafic lower crust

the influence of a finite glaciation phase on predictions of post glacial isostatic adjustment we predict relative sea level rsl variations present day three dimensional 3d crustal deformation rates and baseline velocities and a set of anomalies in the gravitational field of the planet using a suite of models for the space time geometry of the pleistocene ice sheets these models are distinguished on the basis of the details of the glaciation phase and they include the cases of an infinite glaciation phase i e an assumption of isostatic equilibrium at the time of the last glacial maximum lgm a steady uniform glaciation and a glaciation in which the bulk of the accumulation is limited to the final stages of the growth phase comparison of the observational records of postglacial rsl change with predictions based on the assumption of isostatic equilibrium at lgm have commonly been used to infer both the space time geometry of the final deglaciation event and the mantle viscosity we conclude that both these applications may be influenced significantly by the incorporation of a finite glacial cycle as an example rsl predictions which assume isostatic equilibrium at lgm and those which incorporate a relatively rapid glaciation phase can differ by a factor of 2 or more at some sites within previously glaciated regions when an earth model characterized by a lower mantle viscosity of 1022 pa s is adopted we have also found that differences in the adopted model for the glaciation event are capable of explaining entirely the discrepancies 0 2 mm yr between previously published predictions of present day tangential velocities in north america these discrepancies are characterized by a dominant long wavelength signal and hence they do not necessarily influence strongly predictions of baseline velocities variations in the glaciation model can also have an important effect on predictions of peak gravity anomalies over previously glaciated regions and secular variations in the zonal harmonics of the earth s geoid in both cases the effect may be sufficient to alter significantly the signal from other geophysical processes which may need to be invoked to reconcile the observational constraints

long term perspectives on giant earthquakes and tsunamis at subduction histories of earthquakes and tsunamis inferred from geological evidence aid in anticipating future catastrophes this natural warning system now influences building codes and tsunami planning in the united states canada and japan particularly where geology demonstrates the past occurrence of earthquakes and tsunamis larger than those known from written and instrumental records under favorable circumstances paleoseismology can thus provide long term advisories of unusually large tsunamis the extraordinary indian ocean tsunami of 2004 resulted from a fault rupture more than 1000 km in length that included and dwarfed fault patches that had broken historically during lesser shocks such variation in rupture mode known from written history at a few subduction zones is also characteristic of earthquake histories inferred from geology on the pacific rim

glacial isostatic adjustment and the anomalous tide gauge record of eastern north america sea level variations as recorded by the global network of tide gauges represent a rich data set for studying a wide range of natural and anthropogenic phenomena such as the sea level rise induced by possible global warming for this purpose long term sea level trends must be corrected for the contaminating effects of continuing glacial isostatic adjustment1 5 gia the numerical correction procedure has for sites on the east coast of north america yielded a set of highly anomalous sea level rates characterized by systematic geographical trends2 4 5 we demonstrate that these trends are a consequence of inadequacies in the previous standard numerical prediction for gia in particular we find that the well known trends in the gia corrected tide gauge rates are eliminated if the lower mantle viscosity of the earth model used in the gia prediction is increased this result obviates the need to explain the anomalous trend as a manifestation of gulf stream ocean circulation4 or neotectonic processes2

subduction zone paleoseismology along the pacific coast of northeast japan progress and remaining problems abstract this paper reviews recent progress in tsunami geology and the history of coastal uplift subsidence along the pacific coasts of hokkaido and tohoku facing the kuril and japan trenches respectively in the last 20 years research by tsunami geologists in northeast japan has focused on extending the record of tsunamis beyond the range of historical documents in the region which span too little time to reveal much of the earthquake history over the last millennia along the coast of hokkaido recurrent sandy deposits are evidence of historical and prehistoric large tsunamis at kiritappu marsh for example at least 15 identified tsunami deposits occurred between 200 and 6 000 years ago the spatial distribution of the most recent prehistoric tsunami deposit that of the so called 17th century earthquake and tsunami exceeds historical and recent tsunami inundations in eastern hokkaido numerical simulations of this event require a multi segment fault model with variable slip mw 8 8 encompassing both the tokachi oki and nemuro oki regions to reproduce the observed deposit distribution in eastern hokkaido the recurrence interval of such multi segment earthquakes along the southern kuril trench is estimated to be 100 800 years based on tephrochronological and radiocarbon evidence tsunami deposits are also associated with historical earthquakes in 1843 and 1894 in eastern hokkaido and with the 1640 komagatake eruption in western hokkaido the 17th century earthquake probably triggered postseismic coastal deformation diatom based transfer functions suggest rapid subsidence before the event and gradual uplift afterward and historical volcanic ash layers indicate that gradual postseismic uplift occurred over decades a simple dislocation model can explain such gradual uplift as an aseismic fault extension after the 17th century event in the tohoku region a tsunami deposit associated with the 869 jogan earthquake has been identified and the inundation area of this event has been constrained based on the lateral extent of the tsunami deposit and its stratigraphic position beneath the historical to a tephra 915 ce land level changes at odaka fukushima prefecture associated with the jogan event have been estimated based on changes of fossil diatom assemblages below and above the tsunami deposit numerical simulations based on geological evidence and observations of the 2011 tohoku tsunami deposit suggest that the jogan event was a plate boundary rupture at least 200 km long along the japan trench mw 8 3 8 6 the 1454 kyotoku tsunami is also considered to have been generated by a rupture area including the miyagi oki region part of the jogan rupture it remains unclear whether the 869 1454 and 2011 tsunamis were similar in size and source if they were the recurrence intervals of such events near sendai are less than 600 years and more regular than those for multi segment earthquakes along the kuril trench

spatial variability of late holocene and 20th century sea level rise along the atlantic coast of the united states accurate estimates of global sea level rise in the pre satellite era provide a context for 21 st century sea level predictions but the use of tide gauge records is complicated by the contributions from changes in land level due to glacial isostatic adjustment gia we have constructed a rigorous quality controlled database of late holocene sea level indices from the u s atlantic coast exhibiting subsidence rates of 0 8 mm a 1 in maine increasing to rates of 1 7 mm a 1 in delaware and a return to rates 0 9 mm a 1 in the carolinas this pattern can be attributed to ongoing gia due to the demise of the laurentide ice sheet our data allow us to defi ne the geometry of the associated collapsing proglacial forebulge with a level of resolution unmatched by any other currently available method the corresponding rates of relative sea level rise serve as background rates on which future sea level rise must be superimposed we further employ the geological data to remove the gia component from tide gauge records to estimate a mean 20 th century sea level rise rate for the u s atlantic coast of 1 8 0 2 mm a 1 similar to the global average however we fia distinct spatial trend in the rate of 20 th century sea level rise increasing from maine to south carolina this is the fi rst evidence of this phenomenon from observational data alone we suggest this may be related to the melting of the greenland ice sheet and or ocean steric effects

beach ridges as paleoseismic indicators of abrupt coastal subsidence during subduction zone earthquakes and implications for alaska aleutian subduction zone paleoseismology southeast coast of the kenai peninsula alaska abstract the kenai section of the eastern alaska aleutian subduction zone straddles two areas of high slip in the 1964 great alaska earthquake and is the least studied of the three megathrust segments kodiak kenai prince william sound that ruptured in 1964 investigation of two coastal sites in the eastern part of the kenai segment on the southeast coast of the kenai peninsula identified evidence for two subduction zone earthquakes that predate the 1964 earthquake both coastal sites provide paleoseismic data through inferred coseismic subsidence of wetlands and associated subsidence induced erosion of beach ridges at verdant cove paleo beach ridges record the paleoseismic history whereas at quicksand cove buried soils in drowned coastal wetlands are the primary indicators of paleoearthquake occurrence and age the timing of submergence and death of trees mark the oldest earthquake at verdant cove that is consistent with the age of a well documented 900 year ago subduction zone earthquake that ruptured the prince william sound segment of the megathrust to the east and the kodiak segment to the west soils buried within the last 400 450 years mark the penultimate earthquake on the southeast coast of the kenai peninsula the penultimate earthquake probably occurred before ad 1840 from its absence in russian historical accounts the penultimate subduction zone earthquake on the kenai segment did not rupture in conjunction with the prince william sound to the northeast therefore the kenai segment which is presently creeping can rupture independently of the adjacent prince william sound segment that is presently locked

present day vertical deformation of the cascadia margin pacific northwest united states we estimate present day uplift rates along the cascadia subduction zone in california oregon and washington in the pacific northwest united states by utilizing repeated leveling surveys and tide gauge records these two independent data sets give similar profiles for latitudinal variation of contemporary uplift rates along the coast uplift rates are extended inland through east west leveling lines that connect the north south line along the coast to the north south line along the inland valleys just west of the cascades the results are summarized as a contour map of present day uplift rates for the western pacific northwest we find that rates of present day uplift vary latitudinally along the coast and inland valleys as well as longitudinally along transects connecting the coast to the inland valleys long term tidal records of neah bay astoria and crescent city indicate uplift of land relative to sea level of 1 6 0 2 0 0 0 2 and 0 9 0 2 mm yr respectively 1 standard error unlike previous estimates of relative sea level change at astoria we adjust for discharge effects of the columbia river including human management influences after approximating an absolute framework by using 1 8 0 1 mm yr to compensate for global sea level rise results indicate that much of the western pacific northwest is rising at rates between 0 and 5 mm yr the most rapid uplift rates are near the coast particularly near the olympic peninsula the mouth of the columbia river cape blanco and cape mendocino two axes of uplift are identified one trends northeast from the southwest oregon coast and the other trends south southeasterly from the olympic peninsula to the columbia river the puget sound vicinity and a small east west region from the north central oregon coast to the inland willamette valley are subsiding at rates up to 1 mm yr we interpret the overall pattern of rapid present day uplift to be generated by interseismic strain accumulation in the subduction zone this interseismic elastic strain accumulation implies significant seismic hazard

seventeenth century uplift in eastern hokkaido japan shores of eastern hokkaido rose by perhaps i m a few centuries ago the uplifted area extended at least 50km along the southern kuril trench it included the estuaries akkeshi ko and hichirippu on

origin of spatial variation in us east coast sea level trends during 1900 2017 identifying the causes of historical trends in relative sea level the height of the sea surface relative to earth s crust is a prerequisite for predicting future changes rates of change along the eastern coast of the usa the us east coast during the past century were spatially variable and relative sea level rose faster along the mid atlantic bight than along the south atlantic bight and the gulf of maine past studies suggest that earth s ongoing response to the last deglaciation1 5 surface redistribution of ice and water5 9 and changes in ocean circulation9 13 contributed considerably to this large scale spatial pattern here we analyse instrumental data14 15 and proxy reconstructions4 12 using probabilistic methods16 18 to show that vertical motions of earth s crust exerted the dominant control on regional spatial differences in relative sea level trends along the us east coast during 1900 2017 explaining most of the large scale spatial variance rates of coastal subsidence caused by ongoing relaxation of the peripheral forebulge associated with the last deglaciation are strongest near north carolina maryland and virginia such structure indicates that earth s elastic lithosphere is thicker than has been assumed in other models19 22 we also find a substantial coastal gradient in relative sea level trends over this period that is unrelated to deglaciation and suggests contributions from twentieth century redistribution of ice and water our results indicate that the majority of large scale spatial variation in long term rates of relative sea level rise on the us east coast is due to geological processes that will persist at similar rates for centuries vertical motions of earth s crust had the greatest effect on regional spatial differences in relative sea level trends along the eastern coast of the usa during 1900 2017 explaining most of the large scale spatial variance in regional rates of sea level rise

relative and absolute sea level rise in western canada and northwestern united states from a combined tide gauge gps analysis 1 empirical studies and climate models suggest large variations of absolute sea level asl changes between oceanic basins such potential variations raise concern on the applicability of global mean asl predictions to specific regions and on estimates of relative sea level rsl hazards we address this issue for the western canada and northwestern united states coastline by estimating the 20th century asl rate using a combination of 34 colocated tide gauge and global positioning system gps stations the tide gauge data are quality controlled and corrected for spatially and temporally correlated sea level transients in order to derive robust rsl trends and standard errors reference frame and other gps specific issues are considered as part of the error budget in absolute gps vertical velocities our combined tide gauge gps analysis aligned to the international terrestrial reference frame 2000 indicates a northeast pacific asl rise of 1 8 0 2 mm a through the 20th century which is similar to accepted rates for the global eustatic mean for the period 1993 2003 we find a regional asl rate of 4 4 0 5 mm a consistent with satellite altimetry on the basis of the intergovernment panel on climate change assessment report 4 mean scenario and our assessment of coastal motions from gps and tide gauge data we derive a map of predicted 21st century rsl rise in western canada and the northwestern united states variations in coastal uplift strongly affect spatial rsl patterns subsidence of southern puget sound may significantly increase rsl rise in the seattle tacoma metropolitan area conversely tectonic uplift along parts of the outer west coast may reduce future rsl rise by up to 50 100

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

persistent elastic behavior above a megathrust rupture patch nias island west sumatra we quantify fore arc deformation using fossil reefs to test the assumption commonly made in seismic cycle models that anelastic deformation of the fore arc is negligible elevated coral microatolls paleoreef flats and chenier plains show that the sumatran outer arc island of nias has experienced a complex pattern of relatively slow long term uplift and subsidence during the holocene epoch this same island rose up to 2 9 m during the mw 8 7 sunda megathrust rupture in 2005 the mismatch between the 2005 and holocene uplift patterns along with the overall low rates of holocene deformation reflects the dominance of elastic strain accumulation and release along this section of the sunda outer arc high and the relatively subordinate role of upper plate deformation in accommodating long term plate convergence the fraction of 2005 uplift that will be retained permanently is generally 4 for sites that experienced more than 0 25 m of coseismic uplift average uplift rates since the mid holocene range from 1 5 to 0 2 mm a and are highest on the eastern coast of nias where coseismic uplift was nearly zero in 2005 the pattern of long term uplift and subsidence is consistent with slow deformation of nias along closely spaced folds in the north and trenchward dipping back thrusts in the southeast low holocene tectonic uplift rates provide for excellent geomorphic and stratigraphic preservation of the mid holocene relative sea level high which was under way by 7 3 ka and persisted until 2 ka

reconnaissance study of precambrian metamorphic rocks northeastern sino korean shield people s republic of china in eastern liaoning and southern jilin provinces people9s republic of china rocks of late archean early and middle proterozoic ages consist of interlayered recrystallized banded iron formations pelitic schists maric and ultramafic amphibolites and quartzofeldspathic gneisses the latter two lithologies are volumetrically dominant and include both supracrustals and orthogneisses orthoamphibolites new analytical data document the chemically primitive nature of maficultramafic amphibolite and tonalitic granulites of archean age which are overlain and invaded by more evolved proterozoic supracrustal and plutonic units now metamorphosed late archean 2 8 2 9 b y rock types include metakomatiitic metatholeiitic pyroxene bearing amphibolites and granulitic tonalite gneisses early and middle proterozoic fuping wutai 2 4 2 5 b y 1 9 2 0 b y and zhongtiao 1 6 1 8 b y orogenies produced amphibolite epidote amphibolite and anchimetamorphic to greenschist facies overprints respectively mineral assemblages suggest intermediate crustal levels of recrystallization for the late archean low rank granulite facies metamorphism and olig pargasitic hbl ti rich bio opx cpx garn 700 100 c 6 7 kbar progressively shallower depths for early and middle proterozoic amphibolite olig blue green hbl brown bio 500 100 c 5 1 kbar and greenschist alb chi ep act phengite 400 50 c 2 3 kbar facies events late archean and early proterozoic recrystallizations took place under p t conditions characteristic of moderately thick sialic crust and inferred island arc like heat fluxes crustal growth locally terminated and the sino korean craton was stabilized about 1 7 b y ago much later the complex was affected by a thermal event accompanying mesozoic calc alkaline plutonism volcanism apparently during the terrane assembly of east asia