the 2006 2007 kuril islands great earthquake sequence the southwestern half of a 500 km long seismic gap in the central kuril island arc subduction zone experienced two great earthquakes with extensive preshock and aftershock sequences in late 2006 to early 2007 the nature of seismic coupling in the gap had been uncertain due to the limited historical record of prior large events and the presence of distinctive upper plate trench and outer rise structures relative to adjacent regions along the arc that have experienced repeated great interplate earthquakes in the last few centuries the intraplate region seaward of the seismic gap had several shallow compressional events during the preceding decades notably an m s 7 2 event on 16 march 1963 leading to speculation that the interplate fault was seismically coupled this issue was partly resolved by failure of the shallow portion of the interplate megathrust in an m w 8 3 thrust event on 15 november 2006 this event ruptured 250 km along the seismic gap just northeast of the great 1963 kuril island m w 8 5 earthquake rupture zone within minutes of the thrust event intense earthquake activity commenced beneath the outer wall of the trench seaward of the interplate rupture with the larger events having normal faulting mechanisms an unusual double band of interplate and intraplate aftershocks developed on 13 january 2007 an m w 8 1 extensional earthquake ruptured within the pacific plate beneath the seaward edge of the kuril trench this event is the third largest normal faulting earthquake seaward of a subduction zone on record and its rupture zone extended to at least 33 km depth and paralleled most of the length of the 2006 rupture the 13 january 2007 event produced stronger shaking in japan than the larger thrust event as a consequence of higher short period energy radiation from the source the great event aftershock sequences were dominated by the expected faulting geometries thrust faulting for the 2006 rupture zone and normal faulting for the 2007 rupture zone a large intraplate compressional event occurred on 15 january 2009 m w 7 4 near 45 km depth below the rupture zone of the 2007 event and in the vicinity of the 16 march 1963 compressional event the fault geometry rupture process and slip distributions of the two great events are estimated using very broadband teleseismic body and surface wave observations the occurrence of the thrust event in the shallowest portion of the interplate fault in a region with a paucity of large thrust events at greater depths suggests that the event removed most of the slip deficit on this portion of the interplate fault this great earthquake doublet demonstrates the heightened seismic hazard posed by induced intraplate faulting following large interplate thrust events future seismic failure of the remainder of the seismic gap appears viable with the northeastern region that has also experienced compressional activity seaward of the megathrust warranting particular attention

a viscoelastic and afterslip postseismic deformation model for the 1964 alaska earthquake 1 we developed a 3 d viscoelastic model in concert with an afterslip model to describe the postseismic deformation following the 1964 alaska earthquake our model incorporates a realistic geometry including an elastic slab with very low dip angle these geometric factors are important and require a reanalysis of the 1964 coseismic model our coseismic model differs from previous models in that the montague island splay fault extends farther along the kenai peninsula coast and as a result slip on the megathrust in that region is smaller we computed postseismic deformation models using a range of mantle viscosities with maxwell relaxation time of 1 to 50 years with a best estimate of 20 years the viscoelastic model explains most of the trenchward motion observed in the present velocity field but has little impact on cumulative 1965 to present uplifts after removing the viscoelastic response the largest residual cumulative uplifts were located downdip from areas of largest coseismic slip area and we explain them using an afterslip model constrained in space by the observed cumulative postseismic uplifts and in time by tide gauge records no single mechanism can explain both the 30 years of cumulative uplift and the present velocities but a combination of viscoelastic relaxation afterslip interseismic elastic deformation and motion of southern alaska relative to north america explains the first order features of the observations forty years after the earthquake the present day velocities contain a significant component of postseismic deformation so very long lived postseismic deformation plays an important role in the subduction zone earthquake cycle for great earthquakes

implications of the 26 december 2004 sumatra andaman earthquake on tsunami forecast and assessment models for great subduction zone earthquakes results from different tsunami forecasting and hazard assessment mod els are compared with observed tsunami wave heights from the 26 december 2004 indian ocean tsunami forecast models are based on initial earthquake information and are used to estimate tsunami wave heights during propagation an empirical forecast relationship based only on seismic moment provides a close estimate to the observed mean regional and maximum local tsunami runup heights for the 2004 indian ocean tsunami but underestimates mean regional tsunami heights at azimuths in line with the tsunami beaming pattern e g sri lanka thailand standard forecast models developed from subfault discretization of earthquake rupture in which deep ocean sea level observations are used to constrain slip are also tested forecast models of this type use tsunami time series measurements at points in the deep ocean as a proxy for the 2004 indian ocean tsunami a transect of deep ocean tsunami amplitudes recorded by satellite altimetry is used to constrain slip along four subfaults of the m 9 sumatra andaman earthquake this proxy model performs well in comparison to observed tsunami wave heights travel times and inundation patterns at banda aceh hypothetical tsunami hazard assessments models based on end member estimates for average slip and rupture length m w 9 0 9 3 are compared with tsunami observations using average slip low end member and rupture length high end member m w 9 14 consistent with many seismic geodetic and tsunami inversions adequately estimates tsunami runup in most regions except the extreme runup in the western aceh province the high slip that occurred in the southern part of the rupture zone linked to runup in this location is a larger fluctuation than expected from standard stochastic slip models in addition excess moment release 9 deduced from geodetic studies in comparison to seismic moment estimates may gen erate additional tsunami energy if the exponential time constant of slip is less than approximately 1 hr overall there is significant variation in assessed runup heights caused by quantifiable uncertainty in both first order source parameters e g rupture length slip length scaling and spatiotemporal complexity of earthquake rupture

stress dependent power law flow in the upper mantle following the 2002 denali alaska earthquake abstract far field continuous global positioning system gps time series data following the 2002 m7 9 denali alaska earthquake imply that mantle viscoelastic rheology is stress dependent a linear viscous mantle cannot explain fast early displacement rates at the surface that rapidly decay with time whereas a power law rheology where strain rate is proportional to stress raised to the power of 3 5 0 5 provides decay rates and spatial patterns in agreement with observations this is consistent with laboratory measurements for hot wet olivine implying a hydrated mantle and a relatively thin 60 km thick lithosphere beneath south central alaska these results suggest that the viscous strength of the lithosphere varies both spatially and temporally and that effective viscosities inferred from different loading events or observational time periods can differ by up to several orders of magnitude thus the very conditions that enable the inference of rheologic strength transient loading and unloading events significantly alter the effective viscosity

a primitive obtuse angled symmetrodont mammalia from the upper cretaceous of alberta canada an upper molar of an obtuse angled symmetrodont resembling the jurassic tinodontidae is described from the upper cretaceous milk river formation of alberta canada the first post jurassic record of tinodontid like symmetrodonts however in its reduced stylocone and cusp c the specimen shows modifications that might have characterized the origin of the aberrant amphidontidae from more primitive obtuse angled species the phyletic implications of this new symmetrodont are discussed

seismology energy radiation from the sumatra earthquake we determined the duration of high frequency energy radiation from indonesia s great sumatra andaman earthquake 26 december 2004 to be about 500 seconds this duration can be translated into a rupture length of about 1 200 km which is more than twice as long as that inferred from body wave analyses performed soon after the event our analysis was able rapidly to define the extent of rupture thereby aiding the assessment of seismic hazard in the immediate future

the 2004 december 26 indian ocean tsunami impact on sri lanka cascade modelling from ocean to city scales summary the 2004 december 26 indian ocean tsunami severely hit sri lanka although it was not in the direct path of the initial tsunami waves the western coast was struck by diffracted waves that caused much damage the numerical model geowave is used to compute tsunami generation propagation and inundation from the earthquake source to the sri lankan coast a nested grid system is constructed to increase the resolution until galle bay on the southwestern coast where a 20 m grid is used the six nested topobathymetric grids are interpolated from etopo2 and high resolution data at sea as onshore simulation results are compared with tsunami height data from national oceanic and atmospheric administration noaa us and geological survey mines bureau gsmb sri lanka when the grid resolution increases the discrepancy between the model and the data remains on average good whereas its spread increases we then conclude that the order of magnitude of the tsunami height is consistent from the 180 m resolution grid but the spatial imprecision is too high to locally predict reliable water heights nevertheless the comparison between computed time series of sea surface elevation at the colombo tide station and tide gauge data shows a very good agreement as both amplitude and arrival time of the first wave are well reproduced when focusing onshore the modelled inundation limit is compared with the limit measured in the field with its a priori setup computed inundation spreads much farther behind the field limit we then integrate more accurate nearshore conditions into the model non linear shallow water equations are chosen instead of fully non linear boussinesq equations the bottom friction on land is increased to a much higher value than at sea the buildings cover and the low tide conditions are taken into account in the dem the resulting high resolution simulation agrees better with field data even if discrepancies are still locally observed in places of dem imprecision and in a river valley this simulation however demonstrates that taking into account nearshore and onshore features may significantly improve tsunami impact assessment

defining the source region of the indian ocean tsunami from gps altimeters tide gauges and tsunami models abstract to understand the role of the co seismic moment magnitude mw 9 1 9 3 sumatra andaman earthquake rupture mechanism on the severity of the indian ocean tsunami we used permanent global positioning system gps data and carried out an analysis of co seismic displacement and tsunami models tsunami modelling validated against independent jason 1 altimetry data and tsunami arrival time data as determined from tide gauges was used to analyse the results of five co seismic slip inversions using gps seismicity and or uplift data in this way we determined the most likely slip distribution characterized by slip maxima of 20 m in the south and 20 m in the north we used both the distribution and temporal evolution of the co seismic slip as derived from the gps data we show that the 9 min propagation time of the rupture led to constructive interference of waves radiating first from the south and minutes later from the north strengthening the tsunami in southern india sri lanka and thailand we conclude that the incorporation of permanent real time gps stations would represent a valuable component of future tsunami warning systems

variation and taxonomy of asiamerican eutherian mammal paranyctoides a parsimony analysis of the distribution of 408 characters in 73 taxa of cretaceous eutherians and related taxa places three species of paranyctoides the asiatic p quadrans and the north american

rupture process of the 2004 sumatra andaman earthquake from tsunami waveform inversion the aim of this work is to infer the slip distribution and rupture velocity along the rupture zone of the 26 december 2004 sumatra andaman earthquake from available tide gage records of the tsunami we selected waveforms from 14 stations distributed along the coast of the indian ocean then we subdivided the fault plane into 16 subfaults both along strike and downdip following the geometry and mech anism proposed by banerjee et al 2005 and computed the corresponding green s functions by numerical solution of the shallow water equations through a finite difference method the slip distribution and rupture velocity were determined simul taneously by means of a simulated annealing technique we compared the recorded and synthetic waveforms in the time domain using a cost function that is a trade off between the l1 and l2 norms preliminary tests on a synthetic dataset together with a posteriori statistical analysis of the model ensemble enabled us to assess the ef fectiveness of the method and to quantify the model uncertainty the main finding is that the best source model features a nonuniform distribution of coseismic slip with high slip values concentrated into three main patches the first is located in the southern part of the fault off the coast of the aceh province the second between 6 5 n and 11 n and the third at depth between 11 n and 14 n furthermore we estimated that the rupture propagated at an average speed of 2 0 km sec

possible atmospheric origin of the 7 may 2007 western black sea shelf tsunami event 1 the paper examines the possibility that tsunami event recorded in the western black sea on 7 may 2007 was triggered by a traveling atmospheric disturbance as meteotsunamis are favored by specific synoptic conditions we inspected available ground and sounding observations european centre for medium range weather forecasts reanalysis fields and satellite based products and compared them to the documented mediterranean meteotsunamis we found an atmospheric disturbance traveling toward 30 nne with amplitude of 2 3 hpa and propagation speed of about 16 m s passing through few tens of kilometers wide pathway over the region affected by the tsunami this disturbance occurred in the lower troposphere but it was capped by instable convective cell that preserved gravity disturbance s coherence over a region at least 150 km long an ocean modeling study showed that such a disturbance is capable of generating large tsunami waves and strong currents over the shallow regions following the observations over the region where maximum sea level oscillations have been documented therefore this event has a potential to be classified as a meteotsunami the first of such kind in the black sea

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

postseismic rebound in fault step overs caused by pore fluid flow near field strain induced by large crustal earthquakes results in changes in pore fluid pressure that dissipate with time and produce surface deformation synthetic aperture radar sar interferometry revealed several centimeters of postseismic uplift in pull apart structures and subsidence in a compressive jog along the landers california 1992 earthquake surface rupture with a relaxation time of 270 45 days such a postseismic rebound may be explained by the transition of the poisson s ratio of the deformed volumes of rock from undrained to drained conditions as pore fluid flow allows pore pressure to return to hydrostatic equilibrium

effect of 3 d viscoelastic structure on post seismic relaxation from the 2004 m 9 2 sumatra earthquake summary the 2004 m 9 2 sumatra andaman earthquake profoundly altered the state of stress in a large volume surrounding the 1400 km long rupture induced mantle flow fields and coupled surface deformation are sensitive to the 3 d rheology structure to predict the post seismic motions from this earthquake relaxation of a 3 d spherical viscoelastic earth model is simulated using the theory of coupled normal modes the quasi static deformation basis set and solution on the 3 d model is constructed using a spherically stratified viscoelastic earth model with a linear stress strain relation an aspherical perturbation in viscoelastic structure a static mode basis set consisting of earth s spheroidal and toroidal free oscillations a viscoelastic mode basis set and interaction kernels that describe the coupling among viscoelastic and static modes application to the 2004 sumatra andaman earthquake illustrates the profound modification of the post seismic flow field at depth by a slab structure and similarly large effects on the near field post seismic deformation field at earth s surface comparison with postseismic gps observations illustrates the extent to which viscoelastic relaxation contributes to the regional post seismic deformation

spectral wave dissipation over a barrier reef 1 a 2 week field experiment was conducted to measure surface wave dissipation on a barrier reef at kaneohe bay oahu hawaii wave heights and velocities were measured at several locations on the fore reef and the reef flat which were used to estimate rates of dissipation by wave breaking and bottom friction dissipation on the reef flat was found to be dominated by friction at rates that are significantly larger than those typically observed at sandy beach sites this is attributed to the rough surface generated by the reef organisms which makes the reef highly efficient at dissipating energy by bottom friction results were compared to a spectral wave friction model which showed that the variation in frictional dissipation among the different frequency components could be described using a single hydraulic roughness length scale surveys of the bottom roughness conducted on the reef flat showed that this hydraulic roughness length was comparable to the physical roughness measured at this site on the fore reef dissipation was due to the combined effect of frictional dissipation and wave breaking however in this region the magnitude of dissipation by bottom friction was comparable to wave breaking despite the existence of a well defined surf zone there under typical wave conditions the bulk of the total wave energy incident on kaneohe bay is dissipated by bottom friction not wave breaking as is often assumed for sandy beach sites and other coral reefs

numerical modeling of the great 2004 indian ocean tsunami focus on the mascarene islands on 26 december 2004 the m w 9 2 sumatra earthquake triggered the greatest tsunami ever observed in recent times the unprecedented quality and variety of observations on modern instruments provide opportunities to refine modeling techniques as well as our perception of tsunami hazard in oceanic regions where historical events are not as frequent as in the pacific ocean we present a numerical modeling of the 2004 tsunami on the mascarene islands with refined computations on la reunion island where postevent survey observations and one tide gauge record are available we use two different source models models a and b to account for the observations and we also test an additional source model model c to study the effect of a tsunami originating in the 1833 epicentral area southern sumatra a wave trapped on the edge of la reunion may explain the greatest water heights reached in the western coastline of the island the observed tide gauge data are reasonably well fit models a and b the run up data can also be explained with our models late disturbances observed in la pointe des galets may be explained by a late tsunami reflection from madagascar or by harbor resonances finally we also show that model c 1833 like strikes la reunion more heavily than models a and b

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

the mechanism of postseismic deformation triggered by the 2006 2007 great kuril earthquakes received 21 january 2011 accepted 15 february 2011 published 24 march 2011 1 in 2006 2007 a doublet of great earthquakes mw 8 struck in the center of the kuril subduction zone a thrust event followed by an extensional event our observations of the kuril gps array in 2006 2009 outline a broad zone of postseismic deformation with initial horizontal velocities to 90 mm a and postseismic uplift we show that most of the postseismic signal after the great kuril doublet is caused by the viscoelastic relaxation of shear stresses in the weak asthenosphere with the best fitting maxwell viscosity in the range of 5 10 10 17 pa s an order of magnitude smaller than was estimated for several subduction zones we predict that the postseismic deformation will die out in about a decade after the earthquake doublet our results suggest large variations among subduction zones in the asthenospheric viscosity one of the most important rheological parameters citation kogan m g n f vasilenko d i frolov j t freymueller g m steblov b w levin and a s prytkov 2011 the mechanism of postseismic deformation triggered by the 2006 2007 great kuril earthquakes geophys res lett 38 l06304 doi 10 1029 2011gl046855

the terminal triassic catastrophic extinction event in perspective a review of carboniferous through early jurassic terrestrial vertebrate extinction patterns abstract a catastrophic terminal triassic extinction event among terrestrial vertebrates is not supported by available evidence the current model for such an extinction is based on at least eight weak or untenable assumptions 1 a terminal triassic extinction inducing asteroid impact occurred 2 a terminal triassic synchronous mass extinction of terrestrial vertebrates occurred 3 a concurrent terminal triassic marine extinction occurred 4 all terrestrial vertebrate families have similar diversities and ecologies 5 changes in familial diversity can be gauged accurately from the known fossil record 6 extinction of families can be compared through time without normalizing for changes in familial diversity through time 7 extinction rates can be compared without normalizing for differing lengths of geologic stages and 8 catastrophic mass extinctions do not select for small size these assumptions have resulted in unsupportable and or erroneous conclusions carboniferous through early jurassic terrestrial vertebrate families mostly have evolution and extinction patterns unlike the vertebrate evolution and extinction patterns during the terminal cretaceous event only the serpukhovian mid carboniferous extinction event shows strong analogy to the terminal cretaceous event available data suggest no terminal triassic extinction anomaly but rather a prolonged and nearly steady decline in the global terrestrial vertebrate extinction rate throughout the triassic and earliest jurassic

spatially linked asperities of the 2006 2007 great kuril earthquakes revealed by gps 1 in 2006 2007 two great earthquakes ruptured the center of the kuril subduction zone first the interplate thrust event then the intraplate extensional event on the outer rise the affected region was a seismic gap since 1915 published patterns of slip differ for various seismic and tsunami inversions the surface offsets that we measured with gps on the kuril islands are sensitive to the total slip including slow components beyond the seismic and tsunami band we invert coseismic offsets and show that the asperities or regions of high slip are spatially linked for both earthquakes this pattern suggests although does not prove that the first event triggered the second for the 2006 earthquake the asperity is very shallow probably because of the absence of an accretionary prism for the 2007 earthquake our modeling suggests that the rupture occurred in the bent pacific lithosphere to a depth of 50 km

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

the tsunami of 26 december 2004 numerical modeling and energy considerations a numerical model for the global tsunamis computation constructed by kowalik et al 2005 is applied to the tsunami of 26 december 2004 in the world ocean from 80 s to 69 n with spatial resolution of one minute because the computational domain includes close to 200 million grid points a parallel version of the code was developed and run on a cray x1 supercomputer an energy flux function is used to investigate energy transfer from the tsunami source to the atlantic and pacific oceans although the first energy input into the pacific ocean was the primary direct wave reflections from the sri lankan and eastern shores of maldives were a larger source the tsunami traveled from indonesia around new zealand and into the pacific ocean by various routes the direct path through the deep ocean to north america carried miniscule energy while the stronger signal traveled a considerably longer distance via south pacific ridges as these bathymetric features amplified the energy flux vectors travel times for these amplified energy fluxes are much longer than the arrival of the first wave these large fluxes are organized in the wave like form when propagating between australia and antarctica the sources for the larger fluxes are multiple reflections from the seychelles maldives and a slower direct signal from the bay of bengal the energy flux into the atlantic ocean shows a different pattern since the energy is pumped into this domain through the directional properties of the source function the energy flow into the pacific ocean is approximately 75 of the total flow to the atlantic ocean in many locations along the pacific and atlantic coasts the first arriving signal or forerunner has lower amplitude than the main signal which often is much delayed understanding this temporal distribution is important for an application to tsunami warning and prediction

postseismic deformation of the andaman islands following the 26 december 2004 great sumatra andaman earthquake 1 two years after the great sumatra andaman earthquake the 3 1 m wsw coseismic displacement at port blair andaman islands had increased by 32 cm postseismic uplift initially exceeded 1 cm per week and decreased to 1 mm week by 2007 points near port blair had risen more than 20 cm a 24 reversal of coseismic subsidence uplift at eight gps sites suggests a gradual eastward shift of the coseismic neutral axis separating subsidence from uplift simulations of the gps postseismic displacements as viscoelastic relaxation of coseismic stress change and as slip on the plate interface indicate that slip down dip of the seismic rupture dominates near field deformation during the first two years postseismic slip beneath the andaman islands released moment equivalent to a magnitude mw 7 5 earthquake and the distribution suggests deep slip in the stable frictional regime accelerated to catch up to the coseismic rupture

post seismic relaxation following the great 2004 sumatra andaman earthquake on a compressible self gravitating earth summary the mw 9 0 2004 december 26 sumatra andaman and mw 8 7 2005 march 28 nias earthquakes which collectively ruptured approximately 1800 km of the andaman and sunda subduction zones are expected to be followed by vigorous viscoelastic relaxation involving both the upper and lower mantle because of these large spatial dimensions it is desirable to fully account for gravitational coupling effects in the relaxation process we present a stable method of computing relaxation of a spherically stratified compressible and self gravitating viscoelastic earth following an impulsive moment release event the solution is cast in terms of a spherical harmonic expansion of viscoelastic normal modes for simple layered viscoelastic models which include a low viscosity oceanic asthenosphere we predict substantial post seismic effects over a region several 100s of km wide surrounding the eastern indian ocean we compare observed gps time series from ten regional sites mostly in thailand and indonesia beginning in 2004 december with synthetic time series that include the coseismic and post seismic effects of the 2004 december 26 and 2005 march 28 earthquakes a viscosity structure involving a biviscous burgers body rheology in the asthenosphere explains the pattern and amplitude of post seismic offsets remarkably well

tsunami source of the 2004 sumatra andaman earthquake inferred from tide gauge and satellite data tsunami source of the 2004 sumatra andaman earthquake was esti mated from a joint inversion of tsunami waveforms recorded on tide gauges and sea surface heights captured by satellite altimetry measurements the earthquake the largest in the past 40 years caused devastating tsunami damage to countries around the indian ocean but the tsunami source in particular its northern end was not well resolved although aftershocks and crustal deformation extended from off north western sumatra island through the nicobar islands to the andaman islands some seismic wave analyses indicated a shorter source length several hundred kilometers we used tsunami waveforms recorded at 12 tide gauge stations around the source and the sea surface heights measured by three satellites jason1 topex poseidon and envisat we numerically computed tsunami propagation using realistic bathym etry more than 66 000 depth points were digitized from nautical charts and combined with the etopo2 data inversion of satellite data indicates that the tsunami source extended to the andaman islands with a total length of 1 400 km but such a model produces much larger tsunami waveforms than observed at indian tide gauge stations inversion of tide gauge records and the joint inversion indicate that the tsunami source was about 900 km long the largest slip about 13 to 25 m was located off sumatra island and the second largest slip up to 7 m near the nicobar islands the slip distribution is similar for different rupture velocities and rise times with a slow velocity of 1 km sec and a rise time of 3 min yielding the largest variance reduction

viscosity of the asthenosphere from glacial isostatic adjustment and subduction dynamics at the northern cascadia subduction zone british columbia canada 1 late glacial sea level curves located in the cascadia subduction zone csz fore arc in southwestern british columbia show that glacial isostatic adjustment gia was rapid when the cordilleran ice sheet collapsed in the late pleistocene gia modeling with a linear maxwell rheology indicates that the observations can be equally well fit across a wide range of asthenospheric thicknesses provided that the asthenospheric viscosity is varied from 3 1018 pa s for a thin 140 km asthenosphere to 4 1019 pa s for a thick 380 km asthenosphere present day vertical crustal motion predicted by the gia models shows rates of a few tenths of a millimeter per year consistent with previous analyses the model viscosities largely pertain to the viscosity of the oceanic mantle beneath the subducting juan de fuca slab but include a contribution from the mantle wedge above the slab for comparison effective viscosities for the upper mantle due to the tectonic regime subduction were computed using the strain rates and temperatures of an independent geodynamic model of the csz with a wet olivine power law rheology the effective viscosities agree well with gia model viscosities of 1019 pa s or less corresponding to an asthenosphere of 100 or 200 km thickness the agreement suggests a significant role for power law flow in the gia response regardless of the microphysical mechanisms responsible for the gia response the viscosity values inferred from gia can be applied to studies of the megathrust earthquake cycle because both processes take place on comparable time scales

rheology of the lithosphere inferred from postseismic uplift following the 1959 hebgen lake earthquake 1 we have modeled the broad postseismic uplift measured by geodetic leveling in the epicentral area of the 1959 mw 7 3 hebgen lake montana earthquake a normal faulting event in the northern basin and range province to fit the observed uplift we calculate synthetic postseismic deformation using the relaxation response of a gravitational viscoelastic earth to the earthquake for a model with an elastic plate overlying a viscoelastic half space we find that the elastic thickness is 38 8 km which is close to the local crustal thickness the half space viscosity is estimated at 4 1018 0 5 pa s the leveling data do not require a viscous lower crust but permit a lower bound viscosity of 1020 pa s the observed broad uplift cannot be explained by physically plausible afterslip on and below the coseismic fault however local deformation across the coseismic surface rupture requires shallow afterslip reaching the surface the postseismic deformation induced by the estimated viscoelastic structure decays exponentially with a time constant of 15 years because of coupling between the elastic layer and the viscoelastic substrate this relaxation time is significantly longer than the 2 year maxwell relaxation time of the viscous half space itself our result suggests the importance of postseismic relaxation in interpreting high precision global positioning system velocities for example our model results suggest that postseismic transient velocities from both the 1959 hebgen lake and the 1983 mw 6 9 borah peak earthquakes are currently as large as 1 2 mm yr

large trench parallel gravity variations predict seismogenic behavior in subduction zones we demonstrate that great earthquakes occur predominantly in regions with a strongly negative trench parallel gravity anomaly tpga whereas regions with strongly positive tpga are relatively aseismic these observations suggest that over time scales up to at least 1 million years spatial variations of seismogenic behavior within a given subduction zone are stationary and linked to the geological structure of the fore arc the correlations we observe are consistent with a model in which spatial variations in frictional properties on the plate interface control trench parellel variations in fore arc topography gravity and seismogenic behavior

three dimensional viscoelastic finite element model for postseismic deformation of the great 1960 chile earthquake 2 5 10 19 pa s for the continental upper mantle the model well explains the gps observations numerical tests suggest that the continental mantle viscosity value is reasonably well constrained the model shows the prolonged postseismic seaward motion of the inland area to be a unique feature of earthquakes with very long rupture along strike and large coseismic fault slip for short rupture and small coseismic slip the motion will stop very quickly after the earthquake explaining why this phenomenon is not more commonly observed with an oceanic mantle viscosity of 10 20 pa s the model also provides an explanation for tide gauge constrained postseismic uplift 200 km from the trench that had previously been explained using a model of prolonged afterslip of a deep segment of the chile subduction fault index terms 1236 geodesy and gravity rheology of the lithosphere and mantle 8160 1242 geodesy and gravity seismic deformations 7205 3230 mathematical geophysics numerical solutions 7209 seismology earthquake dynamics and mechanics 7260 seismology theory and modeling keywords postseismic deformation viscoelastic stress relaxation gps finite element modeling chile subduction zone upper mantle viscosity

a great earthquake doublet and seismic stress transfer cycle in the central kuril islands temporal variations of the frictional resistance on subduction zone plate boundary faults associated with the stick slip cycle of large interplate earthquakes are thought to modulate the stress regime and earthquake activity within the subducting oceanic plate here we report on two great earthquakes that occurred near the kuril islands which shed light on this process and demonstrate the enhanced seismic hazard accompanying triggered faulting on 15 november 2006 an event of moment magnitude 8 3 ruptured the shallow dipping plate boundary along which the pacific plate descends beneath the central kuril arc the thrust ruptured a seismic gap that previously had uncertain seismogenic potential although the earlier occurrence of outer rise compressional events had suggested the presence of frictional resistance within minutes of this large underthrusting event intraplate extensional earthquakes commenced in the outer rise region seaward of the kuril trench and on 13 january 2007 an event of moment magnitude 8 1 ruptured a normal fault extending through the upper portion of the pacific plate producing one of the largest recorded shallow extensional earthquakes this energetic earthquake sequence demonstrates the stress transfer process within the subducting lithosphere and the distinct rupture characteristics of these great earthquakes illuminate differences in seismogenic properties and seismic hazard of such interplate and intraplate faults

current global plate kinematics from gps 1995 2007 with the plate consistent reference frame 1 we present the vectors of rotation of 10 major lithospheric plates estimated from continuous gps observations at 192 globally distributed stations 71 stations were selected as representing stable plate regions all days for the period 1995 0 2007 0 were included in the analysis in contrast to previous gps plate models our model is independent of international terrestrial reference frames itrf the origin of our plate consistent reference frame is the center of plate rotation cp rather than the center of mass of the entire earth s system cm as in recent versions of itrf we estimate plate rotations and cp by minimizing the misfit between the horizontal velocities predicted by the plate model and the observed gps velocities if any version of itrf is used as the reference frame the drift of the itrf origin relative to cp cannot be neglected in estimation of plate rotation vectors and plate residual station velocities the model of the plate kinematics presented here addresses the problem debated since the beginning of the space geodesy how big are disagreements between the current plate motions and the motions averaged over several million years we compare the vectors of relative plate rotations estimated here with the published vectors from gps and geologic models we also discuss the integrity of individual plates as exhibited by plate residual station velocities for seven largest plates the rms value of plate residual station velocities in stable plate interiors is 0 5 0 9 mm a this value is an upper bound on deviation of real plates from infinite stiffness

summary of fossil vertebrate taxa named by richard c fox with an annotated list of taxa named between 1962 and 2012 and new photographs for non mammalian therapsid and mammalian holotypes erected between 1968 and 1994 beginning in 1962 and extending to the present richard c fox and colleagues have named 87 species of fossil vertebrates 1 fish 4 amphibians 2 choristoderes 12 lizards 1 crocodile 1 dinosaur 2 pelycosaurs 2 non mammalian therapsids and 62 mammals and numerous new supraspecific taxa virtually all of these species continue to be accepted although the higher level assignments of several have been altered the vast majority of the named species were founded on specimens collected during the mid 1960s to early 2000s by field parties under fox s direction from the late cretaceous late santonian to late maastrichtian and paleocene of alberta and saskatchewan canada and that are housed at the university of alberta laboratory for vertebrate paleontology here we present i an annotated list of all fossil vertebrate species named by richard fox between 1962 and 2012 ii updated information on the stratigraphic nomenclature and age estimates for the eight localities in alberta that yielded ho

tsunami impact computed from offshore modeling and coastal amplification laws insights from the 2004 indian ocean tsunami the 2004 indian ocean tsunami gave the opportunity to gather unprecedented tsunami observation databases for various coastlines we present here an analysis of such databases gathered for 3 coastlines among the most impacted in 2004 in the intermediate and far field thailand myanmar se india sri lanka and se madagascar non linear shallow water tsunami modeling performed on a single 4 coarse bathymetric grid is compared to these observations in order to check to which extent a simple approach based on the usual energy conservation laws either green s or synolakis laws can explain the data the idea is to fit tsunami data with numerical modeling carried out without any refined coastal bathymetry topography to this end several parameters are discussed namely the bathymetric depth to which model results must be extrapolated using the green s law or the mean bathymetric slope to consider near the studied coast when using the synolakis law using extrapolation depths from 1 to 10 m generally allows a good fit however a 0 1 m is required for some others especially in the far field madagascar possibly due to enhanced numerical dispersion such a method also allows describing the tsunami impact variability along a given coastline then using a series of scenarios we propose a preliminary statistical assessment of tsunami impact for a given earthquake magnitude along the indonesian subduction conversely the sources mostly contributing to a specific hazard can also be mapped onto the sources providing a first order definition of which sources are threatening the 3 studied coastlines

is there a best source model of the sumatra 2004 earthquake for simulating the consecutive tsunami summary many studies have attempted to invert the fault source of the sumatra 2004 event whereas they mostly consider the same fault geometry they lead to a wide range of potential slip distributions using tsunami modelling with geowave a model based on fully non linear boussinesq equations we investigate the influence of five distinct source models of various origins and the influence of rupture kinematics on the generated tsunami the simulation results are considered both at ocean scale and at country scale we then compare the results along the jason 1 track to the corresponding sea surface height anomaly ssha profile and examine the patterns of maximum sea surface elevation around the bay of bengal and on the eastern and southern coastlines of sri lanka in most cases the synthetic ssha profiles are not very consistent with the observed one although they all display a prevailing first wave the divergence in maximum sea surface elevation appears in particular along the sri lankan coast where three of the models lead to a clearly underestimated tsunami impact the best models derive from purely seismic and geodetic studies that did not consider any tsunami modelling thus suggesting that the methods to invert a fault model from tsunami data still need some adjustment especially concerning the handling of coastal data in addition it is important to consider the rupture kinematics along such a long fault as the generated tsunami is more significant than when considering an instantaneous rupture in the case of the sumatra 2004 event the tsunami impact on sri lanka is notably underestimated if modelled without the rupture kinematics we conclude that for tsunami modelling a complex description of the fault source model is not absolutely necessary but some significant parameters such as rupture kinematics should be taken into account

on the use of satellite altimetry to infer the earthquake rupture characteristics application to the 2004 sumatra event summary standard data and methods such as the inversion of seismic and gps data have been used extensively to infer the details of the 2004 december 26 earthquake the unprecedented large size of this event gave the opportunity to modern altimeters to provide the first clear records of a tsunami in deep ocean therefore allowing us to study the rupture history from an independent perspective we invert the jason 1 and topex poseidon altimetry records considering the new constraints available on the geometry of the fault plane and taking them into account in a 3 d rupture model the data are corrected for the non negligible effect of satellite motion during measurements our results show that the rupture propagated over the 1500 km of subduction zone initially identified by the aftershock distribution with a magnitude of mw 9 1 our solution compares well with the latitudinal distribution of slip inferred from other data sets with a maximum of energy release north of sumatra and two other slip patches near the nicobar and andaman islands based on waveform comparison we assert that the shallow portion of the megathrust offshore banda aceh had slip amplitudes of more than 20 m also we find that significant amounts of slip about 10 m concentrated below the andaman islands and did not propagate on the shallow portion of the interface although synthetic tests tend to show less resolution in the northern part of the rupture this solution is compatible with the near field data gps coral heads and imagery and would allow one to explain the apparent paradox between the large local displacements and the moderate tsunami observed locally finally we demonstrate the rapidly dominating effect of propagation and slip distribution over the rupture velocity and how it precludes the direct estimate of this latter parameter