on the 1470 year pacing of dansgaard oeschger warm events 1 the oxygen isotope record from the greenland ice sheet project 2 gisp2 ice core was reanalyzed in the frequency and time domains the prominent 1470 year spectral peak which has been associated with the occurrence of dansgaard oeschger interstadial events is solely caused by dansgaard oeschger events 5 6 and 7 this result emphasizes the nonstationary character of the oxygen isotope time series nevertheless a fundamental pacing period of 1470 years seems to control the timing of the onset of the dansgaard oeschger events a trapezoidal time series model is introduced which provides a template for the pacing of the dansgaard oeschger events statistical analysis indicates only a 3 probability that the number of matches between observed and template derived onsets of dansgaard oeschger events between 13 and 46 kyr b p resulted by chance during this interval the spacing of the dansgaard oeschger onsets varied by 20 around the fundamental 1470 year period and multiples thereof the pacing seems unaffected by variations in the strength of north atlantic deep water formation suggesting that the thermohaline circulation was not the primary controlling factor of the pacing period

surges around the hawaiian islands from the 2011 tohoku tsunami 1 the 2011 tohoku tsunami devastated the northeastern japan coasts and caused localized damage to coastal infrastructure across the pacific the tsunami resulted in strong currents around the hawaiian islands that led to closure of harbors and marinas for up to 38 h after its arrival we utilize a nonhydrostatic model to reconstruct the tsunami event from the seismic source for elucidation of the physical processes and inference of the coastal hazards a number of tide gauges bottom pressure sensors and adcps provided point measurements for validation and assessment of the model results in hawaii spectral analysis of the computed surface elevation and current reveals complex flow patterns due to multiscale resonance standing waves with 33 75 min period develop along the island chains while oscillations of 27 min or shorter are primarily confined to an island or an island group with interconnected shelves standing edge waves with periods 16 min or shorter which are able to form nodes on the reefs and inside harbors are the main driving force of the observed coastal currents resonance and constructive interference of the oscillation modes provide an explanation of the impacts observed in hawaii with implications for emergency management in pacific island communities

source process of the 2011 tohoku earthquake estimated from the joint inversion of teleseismic body waves and geodetic data including seafloor observation data source model with enhanced reliability by using objectively determined inversion settings the rupture process of the 2011 tohoku earthquake is estimated from the joint inversion of teleseismic body waves and geodetic data using multiple time window analysis to enhance the reliability of the inversion solution two important inversion setting parameters that control the spatiotemporal slip distribution the maximum slip duration of each subfault t sd and the propagation velocity of the first time window v ftw are determined by objective criteria by performing a semblance analysis of small aperture seismic array data of near source strong motion waveforms t sd is determined to be 100 s v ftw is determined to be 2 0 km s from the matching of the teleseismic and geodetic slip models the spatial resolution of geodetic inversion is significantly improved by using seafloor crustal deformation data in the source area in addition to the terrestrial global positioning system network data the estimated seismic moment and the maximum slip are 3 4 1022 n m m w 9 0 and 43 m respectively the total rupture duration is 150 s large slip is seen in the shallow part of the fault surface including the hypocenter and its spatial extent along the trench axis is 300 km this model is consistent with the results of bathymetric surveys and the slip models from tsunami data the relationships among the fault parameters of the characterized source model of the 2011 tohoku earthquake suggest the possibility that saturation of fault width occurs for this huge earthquake online material text s1 denotes the explanation of how the rupture propagation in the dip direction affects the estimated value of maximum slip duration t sd table s1 denotes the detailed information of the teleseismic stations table s2 denotes the detailed information of the terrestrial geodetic stations

geodetic slip model of the 2011 m9 0 tohoku earthquake 1 the three dimensional crustal displacement field as sampled by gps is used to determine the coseismic slip of the 2011 m9 0 tohoku earthquake we employ a spherically layered earth structure and use a combination of onland gps out to 4000 km from the rupture and offshore gps which samples the high slip region on the interplate boundary along the japan trench inversion of the displacement field for dip slip assuming an interplate boundary of variable dip and striking 195 yields a compact slip maximum of about 33 m located 200 km east of sendai the geodetic moment is 4 06 1022 n m corresponding to mw 9 0 the area of maximum slip is concentrated at a depth of about 10 km is updip of the rupture areas of the m 7 miyagi oki earthquakes of 1933 1936 1937 and 1978 and roughly coincides with the rupture area of the m7 1 1981 miyagi oki earthquake the overlap of the 2011 slip area with several preceding ruptures suggests that the same asperities may rupture repeatedly with m 7 events within several decades of one another

quantitative mineralogy from infrared spectroscopic data ii three dimensional mineralogical characterization of the rocklea channel iron deposit western australia this study demonstrates how mineralogy generated from spectroscopic visible near and shortwave infrared reflectance data collected using rapid drill core logging systems can be used to build one two and three dimensional models of the architecture of ore systems with applications toward exploration and mining in particular this study examines both spectroscopic and traditional mining data laboratory geochemistry and field geologist logging from 180 drill holes through the rocklea channel iron deposit in the hamersley region of western australia valuable infrared reflectance spectroscopy based mineralogy includes the types and abundances of iron oxyhydr oxides hematite vitreous goethite and ochreous goethite clays well and poorly ordered kaolin al and fe smectite and carbonates calcite and dolomite algorithms to determine the abundance and composition of these minerals from infrared reflectance spectra were validated in an associated study by haest et al 2012 and were found to be accurate e g root mean square error rmse for fe oxyhydr oxide abundance prediction of 9 1 wt fe petrographic analysis and validated infrared reflectance spectroscopy based mineralogy constrained the stratigraphy in the paleochannel and the paragenetic history of each horizon the rocklea channel iron deposit developed over weathered basalt and metasedimentary rocks with an internal channel stratigraphy dominated from bottom to top by the following 1 well ordered in situ kaolinite and a partially denaturated channel iron deposit 2 poorly ordered transported kaolinite 3 ochreous goethite with scarce ooidal textures no clays and late stage vitreous goethite silica replacement 4 mostly poorly ordered kaolinite and 5 calcrete with associated fe smectite the mineral paragenesis of the rocklea deposit was compared against current models for channel iron deposit formation a key finding is the relationship between parent rock composition superimposed regolith cover and channel iron deposit ore quality which are linked through ground water interactions and the physicochemistries of both the parent rock and the deposit this has implications for both exploration and ore deposit characterization 1 ore grade channel iron deposits can develop several kilometers downstream 50 km in this case from the proposed source rock areas above mafic volcanics and metasediments 2 vitreous goethite calcrete al and fe smectite cover the rocklea deposit and are proposed as potential vectors to channel iron deposit mineralization at depth 3 improved mineralogy from hyperspectral data in terms of iron oxyhydr oxide and clay content composition can improve iron ore resource delineation iron ore processing separation of vitreous and ochreous goethite and pit design differentiating swelling smectite requiring pit walls with lower slopes from kaolin or white mica

rupture process of the 2010 mw 7 8 mentawai tsunami earthquake from joint inversion of near field hr gps and teleseismic body wave recordings constrained by tsunami observations the 25 october 2010 mentawai tsunami earthquake mw 7 8 ruptured the shallow portion of the sunda megathrust seaward of the mentawai islands offshore of sumatra indonesia generating a strong tsunami that took 509 lives the rupture zone was updip of those of the 12 september 2007 mw 8 5 and 7 9 underthrusting earthquakes high rate 1 s sampling gps instruments of the sumatra gps array network deployed on the mentawai islands and sumatra mainland recorded time varying and static ground displacements at epicentral distances from 49 to 322 km azimuthally distributed tsunami recordings from two deepwater sensors and two tide gauges that have local high resolution bathymetric information provide additional constraints on the source process finite fault rupture models obtained by joint inversion of the high rate hr gps time series and numerous teleseismic broadband p and s wave seismograms together with iterative forward modeling of the tsunami recordings indicate rupture propagation 50 km up dip and 100 km northwest along strike from the hypocenter with a rupture velocity of 1 8 km s subregions with large slip extend from 7 to 10 km depth 80 km northwest from the hypocenter with a maximum slip of 8 m and from 5 km depth to beneath thin horizontal sedimentary layers beyond the prism deformation front for 100 km along strike with a localized region having 15 m of slip the seismic moment is 7 2 1020 n m the rupture model indicates that local heterogeneities in the shallow megathrust can accumulate strain that allows some regions near the toe of accretionary prisms to fail in tsunami earthquakes

finite element model predictions of static deformation from dislocation sources in a subduction zone sensitivities to homogeneous isotropic poisson solid and half space assumptions 1 dislocation models can simulate static deformation caused by slip along a fault these models usually take the form of a dislocation embedded in a homogeneous isotropic poisson solid half space hipshs however the widely accepted hipshs assumptions poorly approximate subduction zone systems of converging oceanic and continental crust this study uses three dimensional finite element models fems that allow for any combination including none of the hipshs assumptions to compute synthetic green s functions for displacement using the1995 mw 8 0 jalisco colima mexico subduction zone earthquake and associated measurements from a nearby gps array as an example fem generated synthetic green s functions are combined with standard linear inverse methods to estimate dislocation distributions along the subduction interface loading a forward hipshs model with dislocation distributions estimated from fems that sequentially relax the hipshs assumptions yields the sensitivity of predicted displacements to each of the hipshs assumptions for the subduction zone models tested and the specific field situation considered sensitivities to the individual poisson solid isotropy and homogeneity assumptions can be substantially greater than gps measurement uncertainties forward modeling quantifies stress coupling between the mw 8 0 earthquake and a nearby mw 6 3 earthquake that occurred 63 days later coulomb stress changes predicted from static hipshs models cannot account for the 63 day lag time between events alternatively an fem that includes a poroelastic oceanic crust which allows for postseismic pore fluid pressure recovery can account for the lag time the pore fluid pressure recovery rate puts an upper limit of 10 17 m2 on the bulk permeability of the oceanic crust

two regions of seafloor deformation generated the tsunami for the 13 november 2016 kaikoura new zealand earthquake the 13 november 2016 kaikoura new zealand m w 7 8 earthquake ruptured multiple crustal faults in the transpressional marlborough and north canterbury tectonic domains of northeastern south island the hikurangi trench and underthrust pacific slab terminate in the region south of kaikoura as the subdution zone transitions to the alpine fault strike slip regime it is difficult to establish whether any coseismic slip occurred on the megathrust from on land observations the rupture generated a tsunami well recorded at tide gauges along the eastern coasts and in chatham islands including a 4 m crest to trough signal at kaikoura where coastal uplift was about 1 m and at multiple gauges in wellington harbor iterative modeling of teleseismic body waves and the regional water level recordings establishes that two regions of seafloor motion produced the tsunami including an m w 7 6 rupture on the megathrust below kaikoura and comparable size transpressional crustal faulting extending offshore near cook strait

coseismic slip distribution of the 2011 off the pacific coast of tohoku earthquake m9 0 refined by means of seafloor geodetic data 1 on 11 march 2011 the devastating m9 0 tohoku earthquake occurred on the interface of the subducting pacific plate and was followed by a huge tsunami that killed about 20 000 people several geophysical studies have already suggested that the very shallow portion of the plate interface might have played an important role in producing such a large earthquake and tsunami however the sparsity of seafloor observations leads to insufficient spatial resolution of the fault slip on such a shallow plate interface for this reason the location and degree of the slip has not yet been estimated accurately enough to assess future seismic risks thus we estimated the coseismic slip distribution based on terrestrial gps observations and all available seafloor geodetic data that significantly improve the spatial resolution at the shallow portion of the plate interface the results reveal that an extremely large greater than 50 m slip occurred in a small about 40 km in width and 120 km in length area near the japan trench and generated the huge tsunami the estimated slip distribution and a comparison of it with the coupling coefficient distribution deduced from the analysis of the small repeating earthquakes suggest that the 2011 tohoku earthquake released strain energy that had accumulated over the past 1000 years probably since the jogan earthquake in 869 the accurate assessments of seismic risks on very shallow plate interfaces in subduction zones throughout the world can be obtained by improving the quality and quantity of seafloor geodetic observations

shallow dynamic overshoot and energetic deep rupture in the 2011 mw 9 0 tohoku oki earthquake strong spatial variation of rupture characteristics in the moment magnitude mw 9 0 tohoku oki megathrust earthquake controlled both the strength of shaking and the size of the tsunami that followed finite source imaging reveals that the rupture consisted of a small initial phase deep rupture for up to 40 seconds extensive shallow rupture at 60 to 70 seconds and continuing deep rupture lasting more than 100 seconds a combination of a shallow dipping fault and a compliant hanging wall may have enabled large shallow slip near the trench normal faulting aftershocks in the area of high slip suggest dynamic overshoot on the fault despite prodigious total slip shallower parts of the rupture weakly radiated at high frequencies whereas deeper parts of the rupture radiated strongly at high frequencies

the 16 april 2016 mw 7 8 ms 7 5 ecuador earthquake a quasi repeat of the 1942 ms 7 5 earthquake and partial re rupture of the 1906 ms 8 6 colombia ecuador earthquake the 2016 ecuador m w 7 8 earthquake ruptured the subduction zone boundary between the nazca and south american plates joint modeling of seismic and tsunami observations indicates an 120 km long rupture area beneath the coastline north of the 1998 m w 7 2 rupture the slip distribution reveals two discrete asperities near the hypocenter and around the equator their locations and the patchy pattern are consistent with the prior interseismic geodetic strain which showed highly locked patches also beneath the coastline aftershocks cluster along two streaks one aligned nearly parallel to the plate convergence direction up dip of the main slip patches and the other on a trench perpendicular lineation south of the 1958 rupture zone comparisons of seismic waveforms and magnitudes show that the 2016 event and 1942 earthquakes have similar surface wave magnitude m s 7 5 overlapping rupture areas and similar main pulses of moment rate the same area ruptured as the southernmost portion of the larger earthquake of 1906 m w 8 6 m s 8 6 the seismic behavior reflects persistent heterogeneous frictional properties of the colombia ecuador megathrust

joint inversion of strong motion teleseismic geodetic and tsunami datasets for the rupture process of the 2011 tohoku earthquake 1 the 2011 tohoku earthquake was observed by dense strong motion teleseismic geodetic and tsunami networks we first inverted each of the datasets obtained by the networks separately for the rupture process of the earthquake we then performed checkerboard resolution tests for assessing the resolving power of these datasets in order to overcome the limited resolutions of the separate inversions and differences in their results we performed a quadruple joint inversion of all these data to determine a source model most suitable for explaining all the datasets in the obtained source model the maximum coseismic slip was approximately 35 m and the total seismic moment was calculated to be 4 2 1022 nm which yielded mw 9 0 the main rupture propagated not only in the strike direction but also in the dip direction and included both the deep area called the miyagi oki region and the compact shallow area near the japan trench

modeling of the 2011 japan tsunami lessons for near field forecast during the devastating 11 march 2011 japanese tsunami data from two tsunami detectors were used to determine the tsunami source within 1 5 h of earthquake origin time for the first time multiple near field tsunami measurements of the 2011 japanese tsunami were used to demonstrate the accuracy of the national oceanic and atmospheric administration noaa real time flooding forecast system in the far field to test the accuracy of the same forecast system in the near field a total of 11 numerical models with grids telescoped to 2 arcsec 60 m were developed to hindcast the propagation and coastal inundation of the 2011 japanese tsunami along the entire east coastline of japan using the noaa tsunami source computed in near real time the model results of tsunami propagation are validated with tsunami time series measured at different water depths offshore and near shore along japan s coastline the computed tsunami runup height and spatial distribution are highly consistent with post tsunami survey data collected along the japanese coastline the computed inundation penetration also agrees well with survey data giving a modeling accuracy of 85 5 for the inundation areas along 800 km of coastline between ibaraki prefecture north of kashima and aomori prefecture south of rokkasho the inundation model results highlighted the variability of tsunami impact in response to different offshore bathymetry and flooded terrain comparison of tsunami sources inferred from different indirect methods shows the crucial importance of deep ocean tsunami measurements for real time tsunami forecasts the agreement between model results and observations along japan s coastline demonstrate the ability and potential of noaa s methodology for real time near field tsunami flooding forecasts an accurate tsunami flooding forecast within 30 min may now be possible using the noaa forecast methodology with carefully placed tsunameters and large scale high resolution inundation models with powerful computing capabilities

comparison of earthquake source models for the 2011 tohoku event using tsunami simulations and near field observations selection of the earthquake source used in tsunami models of the 2011 tohoku event affects the simulated tsunami waveform across the near field different earthquake sources based on inversions of seismic waveforms tsunami waveforms and global positioning system gps data give distinguishable patterns of simulated tsunami heights in many locations in tohoku and at near field deep ocean assessment and reporting of tsunamis dart buoys we compared 10 sources proposed by different research groups using the geoclaw code to simulate the resulting tsunami several simulations accurately reproduced observations at simulation sites with high grid resolution many earthquake sources produced results within 20 difference from the observations between 38 and 39 n including realistic inundation on the sendai plain reflecting a common reliance on large initial seafloor uplift around 38 n 0 5 143 25 e 0 75 as might be expected dart data was better reproduced by sources created by inversion techniques that incorporated dart data in the inversion most of the earthquake sources tested at sites with high grid resolution were unable to reproduce the magnitude of runup north of 39 n indicating that an additional source of tsunamigenic energy not present in most source models is needed to explain these observations online material figures of buoy inundation and run up simulations and observations associated data sets and simulation code

the october 28 2012 mw 7 8 haida gwaii underthrusting earthquake and tsunami slip partitioning along the queen charlotte fault transpressional plate boundary the pacific north american plate boundary is undergoing predominantly right lateral strike slip motion along the queen charlotte and fairweather transform faults the queen charlotte fault qcf hosted the largest historical earthquake in canada the 1949 m s 8 1 strike slip earthquake which ruptured from offshore northern haida gwaii several hundred kilometers northwestward on january 5 2013 an m w 7 5 strike slip faulting event occurred near the northern end of the 1949 rupture zone along central and southern haida gwaii the relative plate motion has 20 oblique convergence across the left stepping plate boundary there had been uncertainty in how the compressional component of plate motion is accommodated the october 28 2012 m w 7 8 haida gwaii earthquake involved slightly 20 oblique thrust faulting on a shallow 18 5 northeast dipping fault plane with strike 320 parallel to the qcf consistent with prior inferences of pacific plate underthrusting beneath haida gwaii the rupture extended to shallow depth offshore of moresby island beneath a 25 30 km wide terrace of sediments that has accumulated in a wedge seaward of the qcf the shallow thrusting caused seafloor uplift that generated substantial localized tsunami run up and a modest far field tsunami that spread across the northern pacific prompting a tsunami warning beach closure and coastal evacuation in hawaii although ultimately tide gauges showed less than 0 8 m of water level increase the mainshock rupture appears to have spread with a 2 3 km s rupture velocity over a length of 150 km with slip averaging 3 3 m concentrated beneath the sedimentary wedge the event was followed by a substantial aftershock sequence in which almost all of the larger events involve distributed intraplate normal faulting extending 50 km oceanward from the qcf the highly oblique slip partitioning in southern haida gwaii is distinctive in that the local plate boundary parallel motion on the qcf may be accommodated either by infrequent large strike slip ruptures or by aseismic creep as seems to be the case for deeper oblique relative plate motion beneath haida gwaii while the sedimentary terrace accumulates plate boundary perpendicular compressional strain that releases in almost pure thrust faulting earthquakes seaward of the qcf

kinematic earthquake source inversion and tsunami runup prediction with regional geophysical data rapid near source earthquake source modeling relying only on strong motion data is limited by instrumental offsets and magnitude saturation adversely affecting subsequent tsunami prediction seismogeodetic displacement and velocity waveforms estimated from an optimal combination of high rate gps and strong motion data overcome these limitations supplementing land based data with offshore wave measurements by seafloor pressure sensors and gps equipped buoys can further improve the image of the earthquake source and prediction of tsunami extent inundation and runup we present a kinematic source model obtained from a retrospective real time analysis of a heterogeneous data set for the 2011 mw9 0 tohoku oki japan earthquake our model is consistent with conceptual models of subduction zones exhibiting depth dependent behavior that is quantified through frequency domain analysis of slip rate functions the stress drop distribution is found to be significantly more correlated with aftershock locations and mechanism types when off shore data are included the kinematic model parameters are then used as initial conditions in a fully nonlinear tsunami propagation analysis notably we include the horizontal advection of steeply sloping bathymetric features comparison with post event on land survey measurements demonstrates that the tsunami s inundation and runup are predicted with considerable accuracy only limited in scale by the resolution of available topography and bathymetry we conclude that it is possible to produce credible and rapid kinematic source models and tsunami predictions within minutes of earthquake onset time for near source coastal regions most susceptible to loss of life and damage to critical infrastructure regardless of earthquake magnitude

the 2011 tohoku oki earthquake displacement reaching the trench axis we detected and measured coseismic displacement caused by the 11 march 2011 tohoku oki earthquake moment magnitude mw 9 0 by using multibeam bathymetric surveys the difference between bathymetric data acquired before and after the earthquake revealed that the displacement extended out to the axis of the japan trench suggesting that the fault rupture reached the trench axis the sea floor on the outermost landward area moved about 50 meters horizontally east southeast and 10 meters upward the large horizontal displacement lifted the sea floor by up to 16 meters on the landward slope in addition to the vertical displacement

postseismic response of repeating earthquakes around the 2011 tohoku oki earthquake moment increases due to the fast loading rate we examined the temporal variation of the size of repeating earthquakes related to the 2011 tohoku oki earthquake m9 0 in the northeastern japan subduction zone for the period from july 1984 to the end of 2011 the repeaters m2 5 6 1 show postseismic magnitude increases for most sequences located in the area of large postseismic slip at the downdip extension of the m9 source region the magnitudes of the first events after the m9 earthquake increased by an average of about 0 3 for sequences having three or more earthquakes over the 9 months following it we also examined the slip area in detail for kamaishi repeaters whose magnitudes had been m4 9 0 2 but which increased by about 1 after the m9 earthquake waveform modeling shows that the slip area for the post m9 kamaishi earthquakes overlaps with that before the tohoku oki earthquake but enlarged by about 6 times until the occurrence time of the last event september 2011 in the analysis period the rupture area remained larger than before but appeared to shrink over time the enlargement of the rupture area suggests that an aseismic to seismic transition occurred in the region surrounding the pre m9 repeaters and is most likely related to fast loading of the repeaters due to rapid postseismic slip estimated to have occurred in the area the existence of conditionally stable regions around the repeating earthquakes and or patches slightly larger than the earthquake nucleation sizes may explain such behavior the temporal change of loading rate is an important factor in determining earthquake size in this case

fault parameters of the 1896 sanriku tsunami earthquake estimated from tsunami numerical modeling the june 15 1896 sanriku earthquake generated devastating tsunamis with the maximum run up of 25 m and caused the worst tsunami disaster in the history of japan despite its moderate surface wave magnitude ms 7 2 and weak seismic intensity this is a typical tsunami earthquake which generates anomalously larger tsunamis than expected from its seismic waves previously proposed mechanisms of tsunami earthquakes include submarine slumping and slow rupture in the accretionary wedge or in the subducted sediments in this paper we estimate the fault parameters of the 1896 tsunami earthquake by numerically computing the tsunami and comparing the waveforms with those recorded at three tide gauge stations in japan the result indicates that the tsunami source is very close to the japan trench and the fault strike is parallel to the trench axis the fault width is about 50 km suggesting that the tsunami earthquake is a slow rupture in the subducted sediments beneath the accretionary wedge

direct energy estimation of the 2011 japan tsunami using deep ocean pressure measurements 1 we have developed a method to compute the total energy transmitted by tsunami waves to the case where the earthquake source is unknown by using deep ocean pressure measurements and numerical models tsunami source functions based on the first wave recorded at the two closest tsunameters deep ocean assessment and reporting of tsunamis dart our analysis suggests that the march 11 2011 tohoku oki tsunami generated off japan originated from a 300 400 km long and 100 km wide area and the total propagated energy is 3 1015j with 6 uncertainty measurements from 30 tsunameters and 32 coastal tide stations show excellent agreement with the forecasts obtained in real time our study indicates that the propagated energy and the source location are the most important source characteristics for predicting tsunami impacts interactions of tsunami waves with seafloor topography delay and redirect the energy flux posing hazards from delayed and amplified waves with long duration seafloor topography also gives its spectral imprint to tsunami waves travel time forecast errors are path specific and correlated to the major wave scatterers in the pacific numerical dissipation in the propagation modeling highlights the need of high resolution inundation models for accurate coastal predictions on the other hand it also can be used to account for physical dissipation to achieve efficiency our results provide guidelines for the earliest reliable tsunami forecast warnings of long duration tsunami waves signals and enhancement of the experimental tsunami forecast system we apply the method to quantify the energy of 15 past tsunamis independently from earthquake magnitudes the small tsunami to seismic radiation energy ratios and their variability 0 01 0 8 reinforce the importance of using deep ocean tsunami data the direct measures of tsunamis for estimates of tsunami energy and accurate forecasting

the 2011 magnitude 9 0 tohoku oki earthquake mosaicking the megathrust from seconds to centuries geophysical observations from the 2011 moment magnitude m w 9 0 tohoku oki japan earthquake allow exploration of a rare large event along a subduction megathrust models for this event indicate that the distribution of coseismic fault slip exceeded 50 meters in places sources of high frequency seismic waves delineate the edges of the deepest portions of coseismic slip and do not simply correlate with the locations of peak slip relative to the m w 8 8 2010 maule chile earthquake the tohoku oki earthquake was deficient in high frequency seismic radiation a difference that we attribute to its relatively shallow depth estimates of total fault slip and surface secular strain accumulation on millennial time scales suggest the need to consider the potential for a future large earthquake just south of this event

the february 6 2013 mw 8 0 santa cruz islands earthquake and tsunami the santa cruz islands region has high seismicity near a 90 bend in the boundary between the pacific and australian plates southward along the vanuatu island arc the australian plate under thrusts the pacific plate in a well defined subduction zone westward a transpressional predominantly transform boundary extends to the southern solomon islands subduction zone the santa cruz islands region has upper plate strike slip and normal faulting plate boundary under thrusting outer rise extensional faulting and intraplate compressional faulting on february 6 2013 the largest under thrusting earthquake mw 8 0 that has been instrumentally recorded in the region ruptured the megathrust the epicenter 10 738 s 165 138 e is about 1 north of epicenters of prior large shallow under thrusting events in vanuatu in 1934 m 7 8 and 1966 ms 7 9 and there is overlap of all three events aftershock zones but not their large slip regions at least 10 lives were lost with 6 more missing due to tsunami 1 5 m high striking the town of lata and several villages on the main santa cruz island of nendo ndeni and a nearby small island nibanga inundation of 500 m flooded the lata airport the tsunami was well recorded by dart buoys spanning an unusually wide three quadrant azimuthal aperture iterative modeling of teleseismic broadband p waves and the deep water tsunami recordings resolves the slip distribution there are two large slip patches with a southeastward rupture expansion at about 1 5 km s with the second patch appearing to have ruptured with large slip at the trench the event has relatively low short period seismic wave energy release but a typical overall moment scaled total energy the shallow rupture depth may be associated with the low level of short period energy and a near total stress drop may account for a lack of underthrusting aftershocks among a highly productive aftershock sequence that included three events with m w 7 0

a unified source model for the 2011 tohoku earthquake abstract the devastating 2011 tohoku earthquake was observed by dense networks of geophysical instruments a unified source model was constructed through joint inversion of teleseismic strong motion and geodetic datasets the result indicates that the earthquake consists of three main ruptures after small rupture in the initial 50 s the first rupture expanded at a slow speed of 1 8 km s to the northeast and east the second rupture began 20 s later at the slowest speed of 1 5 km s and became dominant with the largest slip of 36 m the third rupture then played the leading role propagating southward at a speed of 2 5 km s only the tsunami inversion requires an extension of the source fault to a shallow part between the first rupture area and the japan trench recovering tsunamigenic slips larger than 40 m the slow rupture speed and tsunamigenic slips can explain the features of the disaster by the earthquake

probabilistic imaging of tsunamigenic seafloor deformation during the 2011 tohoku oki earthquake diverse observations from the 2011 m w 9 0 tohoku oki earthquake pointed to large coseismic fault slip proximal to the japan trench this seismic failure prompted a reevaluation of the conventional view that the outer forearc is generally aseismic however the nature of near trench fault slip during this event remains debated without consensus on whether slip peaked at the trench or at greater depths here we develop a probabilistic approach to image the spatiotemporal evolution of coseismic seafloor displacement from near field tsunami observations in a bayesian framework we sample ensembles of nonlinear source models parameterized to focus on near trench features incorporating the uncertainty in modeling dispersive tsunami waves in addition to nominal observational errors our models indicate that seafloor in the region of the earthquake was broadly uplifted and tilted seaward approaching the deep ocean trench over length scales of 40 km seafloor uplift peaks at 5 0 6 m near the inner outer forearc transition and decreases to 2 m at the trench axis over a distance of 50 km corresponding to a seafloor tilt of 0 06 0 02 m km over length scales of 20 km peak uplift reaches 7 2 m at the similar location but uplift at the trench is less constrained elastic modeling that reproduces the observed tilt requires a coseismic slip deficit at the trench such a deficit is effectively consistent with a metastable frictional model for the shallowest megathrust while large shallow earthquakes in the region cannot be completely ruled out aseismic deformation is the most likely mode for satisfying the long term slip budget

did a submarine landslide contribute to the 2011 tohoku tsunami many studies have modeled the tohoku tsunami of march 11 2011 as being due entirely to slip on an earthquake fault but the following discrepancies suggest that further research is warranted 1 published models of tsunami propagation and coastal impact underpredict the observed runup heights of up to 40 m measured along the coast of the sanriku district in the northeast part of honshu island 2 published models cannot reproduce the timing and high frequency content of tsunami waves recorded at three nearshore buoys off sanriku nor the timing and dispersion properties of the waveforms at offshore dart buoy 21418 3 the rupture centroids obtained by tsunami inversions are biased about 60 km nne of that obtained by the global cmt project based on an analysis of seismic and geodetic data together with recorded tsunami waveforms we propose that while the primary source of the tsunami was the vertical displacement of the seafloor due to the earthquake an additional tsunami source is also required we infer the location of the proposed additional source based on an analysis of the travel times of higher frequency tsunami waves observed at nearshore buoys we further propose that the most likely additional tsunami source was a submarine mass failure smf i e a submarine landslide a comparison of pre and post tsunami bathymetric surveys reveals tens of meters of vertical seafloor movement at the proposed smf location and a slope stability analysis confirms that the horizontal acceleration from the earthquake was sufficient to trigger an smf forward modeling of the tsunami generated by a combination of the earthquake and the smf reproduces the recorded on near and offshore tsunami observations well particularly the high frequency component of the tsunami waves off sanriku which were not well simulated by previous models the conclusion that a significant part of the 2011 tohoku tsunami was generated by an smf source has important implications for estimates of tsunami hazard in the tohoku region as well as in other tectonically similar regions

rupture process of the 2011 tohoku oki earthquake and absolute elastic strain release 1 on 11 march 2011 the tohoku oki earthquake in eastern japan and the devastating tsunami that followed it caused severe damage and numerous deaths to clarify the rupture process of the earthquake we inverted teleseismic p wave data applying a novel formulation that takes into account the uncertainty of green s function which has been a major error source in waveform inversion the estimated seismic moment is 5 7 1022 nm mw 9 1 associated with a fault rupture 440 km long and 180 km wide along the plate interface the source process is characterized by asymmetric bilateral rupture propagation but we also found continuous slips up dip from the hypocenter which led to a large maximum slip 50 m long slip duration 90 s and a large stress drop 20 mpa the long slip duration large stress drop extensional normal faulting aftershocks in a previously compressional stress regime and low angle normal slips at approximately the depth of the plate interface suggest that the earthquake released roughly all of the accumulated elastic strain on the plate interface owing to exceptional weakening of the fault the stress accumulated on the plate interface was about 20 mpa near the trench and 0 10 mpa in the down dip source region

importance of horizontal seafloor motion on tsunami height for the 2011 mw 9 0 tohoku oki earthquake abstract it is now clear that the 2011 tohoku oki earthquake ruptured the subduction interface all the way to the japan trench however there is significant disagreement about just how much slip occurred at the trench with most geodetic studies locating only a small fraction of the maximum slip there whereas broadband seismic studies put the majority of the slip near the trench measurements of seafloor displacement near the trench also imply more slip there than is estimated by the geodetic studies here by means of a joint inversion of displacement measurements and seafloor pressure data we show that it is possible to reconcile geodetic and seismic studies and that a considerable amount of slip indeed occurred at the trench with slip magnitudes reaching 57 74 of the maximum slip the seafloor displacement predicted by our model agrees very well with independent measurements made close to the trench we also find good agreement between our tsunami model and independent measurements of tsunami height in the ocean and on land re running of the inversion without the near field pressure gauge data however leads to underprediction of the flooding on land even when the seafloor geodetic data are still included thus even if the seafloor geodetic measurements had been available in real time they would still not have allowed reliable prediction of near field tsunami inundation close to the trench the dip of the plate interface is shallow which serves to decrease the vertical motion of the sea floor for any given slip however the horizontal motion is conversely larger because the ocean floor slopes steeply near the trench it acted like a giant wedge converting the horizontal motion of the ground into an uplift of the water column and causing the peak initial tsunami wave height to be twice as high as it would have been from vertical displacement alone

tsunami source of the 2011 tohoku oki earthquake japan inversion analysis based on dispersive tsunami simulations 1 the large tsunami of the 2011 tohoku oki earthquake was clearly recorded by the ocean bottom pressure and gps wave gauges deployed in and around japan we estimated the initial tsunami water height distribution by inversion analysis of the waveforms based on dispersive tsunami simulations the distribution is characterized by a peak height of 8 m located near the trench and the high water 2m region extending landward with a width of 100 km a series of numerical simulations suggests that a relatively steep peak located near the trench is necessary in order to simultaneously reproduce the dispersive wave at a far field station and the near field waveforms furthermore we estimated the coseismic slip distribution at the plate boundary which indicates that large slip 30 m occurred at a depth of 20 km which corresponds to a large slip deficit area in the interseismic period another slip 25 m occurred at the shallower part 10 km during the rupture

preceding coseismic and postseismic slips of the 2011 tohoku earthquake japan 1 we estimated the spatial and temporal evolution of the preceding aseismic slip from january 2003 to january 2011 the coseismic slip of the tohoku earthquake and the postseismic slip after the earthquake based on global positioning system gps data time dependent analysis indicates aseismic slip offshore of miyagi and fukushima prefectures from 2004 associated with a series of subduction earthquakes that overlap the aseismic slip area these preceding aseismic and coseismic slip areas are centered between the centers of the coseismic and afterslip areas of the tohoku earthquake offshore of miyagi prefecture while they overlap the coseismic and afterslip areas of the tohoku earthquake off fukushima prefecture the timing of moment magnitude nine mw9 class earthquakes appears to be controlled by multiple preceding slip events smaller earthquakes and their afterslip the preceding aseismic and coseismic slip decreased the coupling rate off the tohoku coast suggesting the possibility that the preceding slip represented a precursive stage of the tohoku earthquake the afterslip of the tohoku earthquake occurred in an area where the coseismic slip was not large complementing the large coseismic slip zone the afterslip along iwate miyagi extends up to 80 km in depth and is currently the sole mechanism of strain release in this depth range the source region of the anticipated miyagi oki earthquake shows small postseismic slip after the tohoku earthquake reflecting the energy release at the time of the earthquake aftershock activity is roughly governed by an afterslip process

static stress drop in the mw 9 tohoku oki earthquake heterogeneous distribution and low average value static stress drop distribution and its average value over the rupture area contain important information on the mechanics of large earthquakes here we derive static stress drop distributions from 40 published rupture models for the 2011 mw 9 tohoku oki earthquake that are based on various multidisciplinary observations average stress drop value over the fault area encompassed by the 5 m coseismic slip contour is not unusually large for each rupture model the mean for the 40 models is 2 3 1 3 mpa assuming a uniform rigidity 40 gpa the value for the entire rupture zone and with a more realistic rigidity structure will be even lower in the majority of the models local stress drop in parts of the rupture zone well exceeds 20 mpa the heterogeneous stress change distribution with large stress drop being accompanied by large stress increase leads to the small average for the earthquake

slab1 0 a three dimensional model of global subduction zone geometries 1 we describe and present a new model of global subduction zone geometries called slab1 0 an extension of previous efforts to constrain the two dimensional non planar geometry of subduction zones around the focus of large earthquakes slab1 0 describes the detailed non planar three dimensional geometry of approximately 85 of subduction zones worldwide while the model focuses on the detailed form of each slab from their trenches through the seismogenic zone where it combines data sets from active source and passive seismology it also continues to the limits of their seismic extent in the upper mid mantle providing a uniform approach to the definition of the entire seismically active slab geometry examples are shown for two well constrained global locations models for many other regions are available and can be freely downloaded in several formats from our new slab1 0 website http on doi gov d9arbs we describe improvements in our two dimensional geometry constraint inversion including the use of average active source seismic data profiles in the shallow trench regions where data are otherwise lacking derived from the interpolation between other active source seismic data along strike in the same subduction zone we include several analyses of the uncertainty and robustness of our three dimensional interpolation methods in addition we use the filtered subduction related earthquake data sets compiled to build slab1 0 in a reassessment of previous analyses of the deep limit of the thrust interface seismogenic zone for all subduction zones included in our global model thus far concluding that the width of these seismogenic zones is on average 30 larger than previous studies have suggested

effects of dispersion in tsunami green s functions and implications for joint inversion with seismic and geodetic data a case study of the 2010 mentawai mw 7 8 earthquake tsunami observations play an important role in resolving offshore earthquake slip distributions nondispersive shallow water models are often used with a static initial sea surface pulse derived from seafloor deformation in computation of tsunami green s functions we compare this conventional approach with more advanced techniques based on a dispersive model with a static initial sea surface pulse and with the surface waves generated from kinematic seafloor deformation these three sets of tsunami green s functions are implemented in finite fault inversions with and without seismic and geodetic data for the 2010 mentawai m w 7 8 tsunami earthquake seafloor excitation and wave dispersion produce more spread out waveforms in the green s functions leading to larger slip with more compact distribution through the inversions the fit to the recorded tsunami and the deduced seismic moment which reflects the displaced water volume are relatively insensitive to the approach used for computing green s functions

tsunami surges around the hawaiian islands from the 1 april 2014 north chile mw 8 1 earthquake the 1 april 2014 iquique mw 8 1 earthquake ruptured a segment of the megathrust fault offshore of northern chile and generated a moderate size tsunami across the pacific tide gauges in hawaii recorded over 1 m of wave height despite the long distance from the source and position away from the main radiated energy lobe inversion of global teleseismic body waves combined with forward modeling of the tsunami at four near field dart stations arrives iteratively at a self consistent finite fault model with very compact dimensions the slip distribution produces a nne ssw trending seafloor uplift patch that enhances the tsunami directionality in the wnw resulting in good matches to observed dart and tide gauge records around the hawaiian islands the relatively large waves at selected locations in hawaii can be attributed to a combination of the spatial slip distribution and the resulting short period waves that triggered localized resonance over the insular shelves this event highlights the importance of characterizing detailed slip distributions in analysis or forecasting of tsunamis even for a compact source

estimating the effect of earth elasticity and variable water density on tsunami speeds the speed of tsunami waves is typically calculated using the shallow water approximation over a rigid body earth recent comparisons of tsunami arrival times from the 11 march 2011 tsunami suggest however that the standard formulation has errors around the 1 level and it has been suggested that the elasticity of the earth can explain the discrepancy while previous work has indeed shown that such elastic deformation can modify tsunami speeds the effect has been neglected partly due to the difficulty in understanding how large this elastic effect is here we remedy this by providing a new derivation and expression for how to incorporate the first order effect that solid earth elasticity and ocean water compressibility have on tsunami speeds this result is shown to agree approximately with previous theory and helps to explain observed timing discrepancies from the 11 march 2011 tsunami the dispersive elastic correction and the non dispersive compressibility correction together may account for the majority of the observed discrepancy

survey of 2011 tohoku earthquake tsunami inundation and run up 1 at 14 46 local time on march 11 2011 a magnitude 9 0 earthquake occurred off the coast of northeast japan this earthquake generated a tsunami that struck japan as well as various locations around the pacific ocean with the participation of researchers from throughout japan joint research groups conducted a tsunami survey along a 2000 km stretch of the japanese coast more than 5300 locations have been surveyed to date generating the largest tsunami survey dataset in the world on the sendai plain the maximum inundation height was 19 5 m and the tsunami bore propagated more than 5 km inland along the ria coast from about 50 to 200 km north of sendai the narrow bays focused the tsunami waves generating the largest inundation heights and run ups the survey data clearly show a regional dependence of tsunami characteristics

trench normal variation in observed seafloor displacements associated with the 2011 tohoku oki earthquake 1 seafloor geodetic measurements using the gps acoustic technique just above the rupture area of the 2011 tohoku oki earthquake revealed strong trench normal variation in the horizontal crustal displacement associated with the earthquake one set of observations at a site only 50 km away from the trench yielded the most trench ward data ever reported with an accuracy better than 1 m it showed a coseismic displacement of up to 31 m whereas another set of observations 100 km away from the trench showed a 15 m displacement these horizontal data as well as vertical data from pressure gauges and tsunami observations strongly indicate that the seismic slip reached the trench they are also likely to contribute quantitatively to further investigations that reveal the coseismic behavior of the frontal wedge of the overriding plate in the source region along the japan trench

displacement above the hypocenter of the 2011 tohoku oki earthquake the moment magnitude m w 9 0 2011 tohoku oki mega thrust earthquake occurred off the coast of northeastern japan combining global positioning system gps and acoustic data we detected very large sea floor movements associated with this event directly above the focal region an area with more than 20 meters of horizontal displacement that is four times larger than those detected on land stretches several tens of kilometers long along the trench the largest amount reaches about 24 meters toward east southeast just above the hypocenter furthermore nearly 3 meters of vertical uplift occurred contrary to observed terrestrial subsidence

validation of linearity assumptions for using tsunami waveforms in joint inversion of kinematic rupture models application to the 2010 mentawai mw 7 8 tsunami earthquake tsunami observations have particular importance for resolving shallow offshore slip in finite fault rupture model inversions for large subduction zone earthquakes however validations of amplitude linearity and choice of subfault discretization of tsunami green s functions are essential when inverting tsunami waveforms we explore such validations using four tsunami recordings of the 25 october 2010 mentawai m w 7 8 tsunami earthquake jointly inverted with teleseismic body waves and 1 hz gps high rate gps observations the tsunami observations include near field and far field deep water recordings as well as coastal and island tide gauge recordings a nonlinear dispersive modeling code neowave is used to construct tsunami green s functions from seafloor excitation for the linear inversions along with performing full scale calculations of the tsunami for the inverted models we explore linearity and finiteness effects with respect to slip magnitude variable rake determination and subfault dimensions the linearity assumption is generally robust for the deep water recordings and wave dispersion from seafloor excitation is important for accurate description of near field green s functions breakdown of linearity produces substantial misfits for short wavelength signals in tide gauge recordings with large wave heights including the tsunami observations in joint inversions provides improved resolution of near trench slip compared with inversions of only seismic and geodetic data two rupture models with fine grid 15 km and coarse grid 30 km spacing are inverted for the mentawai event stronger regularization is required for the fine model representation both models indicate a shallow concentration of large slip near the trench with peak slip of 15 m fully nonlinear forward modeling of tsunami waveforms confirms the validity of these two models for matching the tsunami recordings along with the other data

evidence of large scale repeating slip during the 2011 tohoku oki earthquake 1 the repetition of slip during rupture process of earthquake is a debate issue which had never been confirmed clearly in the past big events due to the lack of dense near field observations and limited resolution in time of source model the 2011 m9 0 tohoku oki earthquake generated a wealth seismic records which provided us an unprecedented opportunity to study the rupture evolution of giant earthquake at a high spatio temporal resolution here we use teleseismic local strong motion and near field coseismic geodetic data to investigate the source rupture process of this event based on the parallel inversion technique the results reveal a broad slip zone with remarkable large scale repeating slip during the earthquake the inverted source model shows several time periods of energy release with three main peaks these energy bursts and temporal rupture snapshots suggest repetition of a large scale slip on the biggest asperity this rupture behavior resulted in 50 m slips on the slip zone and prolonged the entire rupture process for a long duration of 160 seconds the proposed source model is in a good agreement with the aftershock distribution and can interpret the characteristics of local strong motions further investigations of repeating slip during this event are crucial which will deeply transform earthquake science from dynamic point of view

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

source model of the great 2011 tohoku earthquake estimated from tsunami waveforms and crustal deformation data the slip distribution of the 11 march 2011 tohoku earthquake is inferred from tsunami waveforms gps data and seafloor crustal deformation data the major slip region extends all the way to the trench and the large slip area extends 300 km long and 160 km wide the largest slip of 44 m is located up dip of the hypocenter the large slip amount about 41 m ruptured the plate interface near the trench the seismic moment calculated from the estimated slip distribution is 5 5 10 22 n m mw 9 1 the large tsunami due to the 2011 tohoku earthquake is generated from those large slip areas near the trench the additional uplift at the sedimentary wedge as suggested for the 1896 sanriku earthquake may have occurred during the 2011 tohoku earthquake too

tsunami generation by horizontal displacement of ocean bottom tsunami generation by an earthquake is generally modeled by water surface displacement identical to the vertical deformation of ocean bottom due to faulting the effect of horizontal deformation is usually neglected however when the tsunami source is on a steep slope and the horizontal displacement is large relative to the vertical displacement the effect becomes significant we show this for two recent earthquakes which generated much larger tsunamis than expected from seismic waves in the case of the 1994 june 2 java indonesia earthquake the focal mechanism was a very shallow dipping thrust and the source was near a very steep trench slope in the case of the 1994 nov 14 mindoro philippines earthquake strike slip faulting extended from ocean to land perpendicular to the coast line in both cases we found that the horizontal motion of slope had an important contribution to the tsunami generation

numerical simulation of the 2011 tohoku tsunami based on a new transient fem co seismic source comparison to far and near field observations in this work we simulate the 2011 m9 tohoku oki tsunami using new coseismic tsunami sources based on inverting onshore and offshore geodetic data using 3d finite element models fem such fems simulate elastic dislocations along the plate boundary interface separating the stiff subducting pacific plate from the relatively weak forearc and volcanic arc of the overriding eurasian plate due in part to the simulated weak forearc materials such sources produce significant shallow slip several tens of meters along the updip portion of the rupture near the trench to assess the accuracy of the new approach we compare observations and numerical simulations of the tsunami s far and near field coastal impact for i one of the standard seismic inversion sources ucsb shao et al 2011 and ii the new fem sources specifically results of numerical simulations for both sources performed using the fully nonlinear and dispersive boussinesq wave model funwave tvd are compared to dart buoy gps tide gauge and inundation runup measurements we use a series of nested model grids with varying resolution down to 250 m nearshore and size and assess effects on model results of the latter and of model physics such as when including dispersion or not we also assess the effects of triggering the tsunami sources in the propagation model i either at once as a hot start or with the spatiotemporal sequence derived from seismic inversion and ii as a specified surface elevation or as a more realistic time and space varying bottom boundary condition in the latter case we compute the initial tsunami generation up to 300 s using the non hydrostatic model nhwave although additional refinements are expected in the near future results based on the current fem sources better explain long wave near field observations at dart and gps buoys near japan and measured tsunami inundation while they simulate observations at distant dart buoys as well or better than the ucsb source none of the sources however are able to explain the largest runup and inundation measured between 39 5 and 40 25 n which could be due to insufficient model resolution in this region sanriku ria of complex bathymetry topography and or to additional tsunami generation mechanisms not represented in the coseismic sources e g splay faults submarine mass failure this will be the object of future work

tsunami waveform inversion for sea surface displacement following the 2011 tohoku earthquake importance of dispersion and source kinematics this paper considers the importance of model parameterization including dispersion source kinematics and source discretization in tsunami source inversion we implement single and multiple time window methods for dispersive and nondispersive wave propagation to estimate source models for the tsunami generated by the 2011 tohoku oki earthquake our source model is described by sea surface displacement instead of fault slip since sea surface displacement accounts for various tsunami generation mechanisms in addition to fault slip the results show that tsunami source models can strongly depend on such model choices particularly when high quality open ocean tsunami waveform data are available we carry out several synthetic inversion tests to validate the method and assess the impact of parameterization including dispersion and variable rupture velocity in data predictions on the inversion results although each of these effects has been considered separately in previous studies we show that it is important to consider them together in order to obtain more meaningful inversion results our results suggest that the discretization of the source the use of dispersive waves and accounting for source kinematics are all important factors in tsunami source inversion of large events such as the tohoku oki earthquake particularly when an extensive set of high quality tsunami waveform recordings are available for the tohoku event a dispersive model with variable rupture velocity results in a profound improvement in waveform fits that justify the higher source complexity and provide a more realistic source model

tsunami source uncertainty estimation the 2011 japan tsunami this article was published in the journal of geophysical research solid earth 2016 american geophysical union and the definite version is available at http dx doi org 10 1002 2015jb012764 the journal s website is at http onlinelibrary wiley com doi 10 1002 2015jb012764 abstract jsessionid bf5813b61924fb094f31bc8f213840a1 f02t04

hydrostatic versus non hydrostatic modeling of tsunamis with implications for insular shelf and reef environments abstract dispersion is known to separate frequency components and reduce the amplitude of tsunami waves in the open ocean the present paper elucidates a reverse process in which the dispersed wave components from trans oceanic propagation of the 2011 tohoku tsunami regroup over the insular shelves and reefs of hawaii the non hydrostatic and hydrostatic modes of a nonlinear long wave model describe the pertinent processes with and without dispersion using the same system of two way nested grids for direct comparison both solutions have very similar amplitude spectra across the ocean and reproduce the dominant components of recorded surface elevations and currents in hawaii despite their markedly different offshore waveforms the hydrostatic solution shows early arrival of short period signals from nonlinear scattering around the hawaiian islands and faster attenuation of the amplitude due to their local source the short period trailing waves from dispersion more effectively excite shelf and reef oscillations giving rise to better agreement with both the amplitude and phase of the recorded data even with larger offshore wave amplitude a hydrostatic model trends to underestimate the surge elevation and current velocity at coastlines fronted by shallow reefs susceptible to resonance oscillations associated with edge waves