the 2004 sumatra tsunami in the southeastern pacific ocean new global insight from observations and modeling the 2004 sumatra tsunami was an unprecedented global disaster measured throughout the world oceans the present study focused on a region of the southeastern pacific ocean where the westward circumferentially propagating tsunami branch converged with the eastward branch based on data from fortuitously placed chilean dart 32401 and tide gauges along the coast of south america by comparison of the tsunami and background spectra we suppressed the influence of topography and reconstructed coastal spectral ratios that were in close agreement with a ratio at dart 32401 and spectral ratios in other oceans findings indicate that even remote tsunami records carry spectral source signatures birth marks the 2004 tsunami waves were found to occupy the broad frequency band of 0 25 10 cph with the prominent ratio peak at period of 40 min related to the southern fast slip source domain this rupture hot spot of 350 km was responsible for the global impact of the 2004 tsunami data from dart 32401 provided validation of model results the simulated maximum tsunami wave height of 2 25 cm was a conservative approximation to the measured height of 2 05 cm the computed tsunami travel time of 25 h 35 min to dart 32401 although 20 min earlier than the actual travel time provided a favorable result in comparison with 24 h 25 min estimated from classical kinematic theory the numerical simulations consistently reproduced the wave height changes observed along the coast of south america including local amplification of tsunami waves at the northern stations of arica 72 cm and callao 67 cm

the 2009 samoan and 2010 chilean tsunamis recorded on the pacific coast of russia two remote tsunamis were recorded on the pacific coast of russia a relatively weak samoan tsunami of september 29 2009 and a much stronger chilean tsunami of february 28 2010 in the area of the south kuril islands records were obtained using autonomous bottom pressure gauges of the institute of marine geology and geophysics imgg additionally for the oceanic coast of the kamchatka peninsula paramushir and bering islands we used data transmitted from coastal tide gauges of the russian tsunami warning service tws the maximum trough to crest heights of the samoan tsunami were about 30 40 cm and were recorded about 3 h after the first tsunami arrival the maximum chilean tsunami trough to crest wave heights were 218 cm at severo kurilsk 187 cm at tserkovnaya bay shikotan island and 140 cm at khodutka bay kamchatka peninsula the time between first and maximum waves reached 4 h strong sea level oscillations for both events range for a long time about 15 17 h the samoan tsunami induced high frequency oscillations a considerable increase in spectral energy in the tsunami spectrum was observed at periods of 4 20 min in contrast the chilean tsunami induced low frequency oscillations the dominant periods were 30 80 min a probable reason for these differences is the different extensions of the source areas the chilean source was much larger than the samoan source and the different energy radiation directions from the sources local topography resonant effects were the main reason of well expressed peaks in power spectra in different areas with a period of 10 min khodutka bay 19 20 min malokurilskaya and tserkovnaya bays 29 min krabovaya inlet and 43 min avachinskaya guba and nikolskoe

the el salvador and philippines tsunamis of august 2012 insights from sea level data analysis and numerical modeling we studied two tsunamis from 2012 one generated by the el salvador earthquake of 27 august mw 7 3 and the other generated by the philippines earthquake of 31 august mw 7 6 using sea level data analysis and numerical modeling for the el salvador tsunami the largest wave height was observed in baltra galapagos islands 71 1 cm located about 1 400 km away from the source the tsunami governing periods were around 9 and 19 min numerical modeling indicated that most of the tsunami energy was directed towards the galapagos islands explaining the relatively large wave height there for the philippines tsunami the maximum wave height of 30 5 cm was observed at kushimoto in japan located about 2 700 km away from the source the tsunami governing periods were around 8 12 and 29 min numerical modeling showed that a significant part of the far field tsunami energy was directed towards the southern coast of japan fourier and wavelet analyses as well as numerical modeling suggested that the dominant period of the first wave at stations normal to the fault strike is related to the fault width while the period of the first wave at stations in the direction of fault strike is representative of the fault length

the krasnouralsky profile in the middle urals russia a tomographic approach to vintage dss data abstract the middle urals region has been widely studied with geophysical methods over the past decades an integrated program is in progress to summarize this knowledge including modern reprocessing of controlled source seismic data this work is devoted to the krasnouralsky dss profile we applied modern tomography inversion algorithms in 2d and 2 5d on first break traveltime picks from an archive catalogue a number of initial models and various smoothing constraints were used to investigate the influence of starting models on the final model robustness and uncertainty of the recovered models were estimated with hypothesis testing and checkerboard tests the recovered velocity structure shows a thicker crust below the contact of the west uralian zone and the central uralian zone and below the tagil magnitogorsk zone deep high velocity anomalies on both sides of this zone are interpreted as crustal thinning or alteration of the crust by intrusions of mantle material our results suggest that it is worthwhile reinterpreting dss traveltime data with modern inversion techniques

the dual source region for the 2004 sumatra tsunami 1 wave arrival times obtained from coastal tide gage and satellite altimetry records for the indian ocean are used to delineate the source region for the december 26 2004 sumatra tsunami findings define a curved 250 km wide 1000 km long tsunami source region centered over the sunda subduction zone which closely matches the seismic source estimated from broadband geophysical data imbedded in this general region are hot spots associated with the southern fast slip and northern slow slip domains which served as distinct source areas for the destructive waves that inundated the coast of the indian ocean

effect of variable bathymetry on the amplitude of teleseismic tsunamis a ray tracing experiment we apply surface wave ray tracing techniques to tsunami propagation in an ocean of variable depth because tsunami velocities are proportional to the square root of the depth of the water column the juxtaposition of oceanic plateaux and basins generates strong lateral velocity gradients and bathymetric features can act as lenses focusing or defocusing the tsunami waves we present a reconstruction of the tsunami wave field from the great chilean earthquake of 1960 an order of magnitude computation based on the concept of ray density provides qualitative agreement with observations at several sites in the pacific ocean we also demonstrate the possibility of using reciprocal maps to identify tsunamigenic zones that present particular danger for a given receiving shore

tide gauge observations of the indian ocean tsunami december 26 2004 the magnitude 9 0 earthquake centered off the west coast of northern sumatra 3 307 n 95 947 e on december 26 2004 at 00 59 utc united states geological survey usgs 2005 usgs earthquake hazards program latest earthquakes earthquake hazards program http earthquake usgs gov eqinthenews 2004 usslav 2005 generated a series of tsunami waves that devastated coastal areas throughout the indian ocean tide gauges operated on behalf of national and international organizations recorded the wave form at a number of island and continental locations this report summarizes the tide gauge observations of the tsunami in the indian ocean available as of january 2005 and provides a recommendation for the use of the basin wide tide gauge network for future warnings

is there a remnant variscan subducted slab in the mantle beneath the paris basin implications for the late variscan lithospheric delamination process and the paris basin formation abstract the paris basin northern france is a late paleozoic mesozoic intracratonic basin that settled upon the collapsed variscan collisional belt the lithospheric roots of the variscan orogenic system below the paris basin have been investigated using a european scale p wave velocity tomographic model tomography points out the existence of a significant high velocity anomaly in the upper mantle below the western part of the basin at 150 200 km depth the anomaly extends with a nw se trend along the buried northern france trace of the northern variscan suture zone i e the bray segment of the upper carboniferous lizard rhenohercynian lrh suture moreover the high velocity anomaly is spatially correlated with the prominent paris basin magnetic anomaly its downdip extent reaches depths greater than 200 km below the southern margin of the paris basin as suggested in previous tomographic studies below ancient suture zones these data argue for such anomaly being the remnant of a variscan subducted slab that escaped the extensive late orogenic delamination process affecting the lithospheric roots by late carboniferous early permian times and that was preserved stable over 300 ma at the base of the lithosphere on a general geodynamical perspective these results provide a new insight into the long term evolution of subducted lithosphere into the mantle in the case of the western european variscan orogenic belt they suggest that the subduction of the lrh slab below the previously thickened variscan crust and its final detachment from the orogenic root have played an important role in the collapse of the belt inducing thermal erosion and extension of the overriding lithosphere the spatial evolution of late orogenic extension across the belt and of subsequent thermal subsidence in the paris basin is suggested to result from the heterogeneous delamination of the lithospheric roots along strike and from the resultant pattern of asthenospheric rise

the influence of sea surface temperature on surface wind in the eastern equatorial pacific weekly to monthly variability abstract temporal correlations between near equatorial surface wind and sea surface temperatures sst at 11 w in the eastern pacific ocean are investigated using data from an array of moored sensors between 5 n and 5 s the signature of tropical instability waves with periods of 20 30 days is apparent in time series of sst and both the meridional and zonal wind components results indicate the existence of a band of pronounced horizontal divergence in the surface wind field associated with the large meridional sst gradient equatorial front normally located just north of the equator perturbations of the equatorial front by the instability waves induce fluctuations in the overlying winds evidence of the air sea coupling is stronger in time series of the meridional gradients of wind and sst than between time series of the variables themselves the meridional differencing serves as a high pass filter in the space domain which removes planetary scale wind fluctuations that are unrelated to the local sst

air sea heat exchange along the northern sea surface temperature front in the eastern tropical pacific abstract the atmospheric response to the oceanic forcing in the eastern pacific along the northern equatorial sea surface temperature sst front is investigated in terms of sensible and latent heat flux during the 6 month period from 28 july 1999 to 27 january 2000 and the 7 month period from 28 june 2000 to 27 january 2001 of particular interest is the atmospheric boundary layer abl response to oceanic tropical instability waves tiws that distort the sst front during may january in normal years in previous studies time series of surface heat fluxes clearly show the influence of tiws but the relationship to spatial patterns of sst and wind speed has been inferred only from sparse in situ data in this study satellite observations are used as a basis for compositing in situ data from moorings to compensate for the lack of a spatially dense mooring array the variability in the position of the sst front caused by westward propagating tiws enables fixed mooring locations to measure the abl response

darts and cork in cascadia basin high resolution observations of the 2004 sumatra tsunami in the northeast pacific 1 we report unique deep sea recordings of the sumatra tsunami of december 2004 by high resolution dart deep ocean assessment and reporting of tsunami and cork circulation obviation retrofit kit bottom pressure sensors deployed at depths of 1500 3500 m in cascadia basin in the northeast pacific the simultaneous records from these sites establish the first ever regional scale tsunami detection array for the open ocean enabling us to resolve both seafloor and crustal tsunami signals and to determine fundamental properties of the waves following their 22 000 km journey from the source region waves reaching the basin had mean amplitudes of 5 mm with energy spread over a broad frequency band from 0 4 to 7 cph peak tsunami energy was in the 0 8 to 2 cph 75 to 30 min band leading waves from the event arrived 34 35 h after the earthquake roughly 7 h later than expected suggesting that the tsunami mainly propagated by the most economic minimum energy loss path along mid ocean ridge wave guides rather than taking the direct and fastest path across the ocean motions within the peak energy band comprise roughly 50 coherent progressive waves propagating from the south at longwave phase speeds of 150 ms 1 and 50 random waves scattered from the coast and bottom irregularities tsunami amplitudes in the borehole were one third those on the seafloor the extensive ringing and anomalously slow 3 5 day e folding decay time of the tsunami wave energy indicates long duration energy flux radiating from the indian ocean via the southern pacific ocean

odessa tsunami of 27 june 2014 observations and numerical modelling on 27 june a 1 2 m high wave struck the beaches of odessa the third largest ukrainian city and the neighbouring port town illichevsk northwestern black sea throughout the day prominent seiche oscillations were observed in several other ports of the black sea tsunamigenic synoptic conditions were found over the black sea stretching from romania in the west to the crimean peninsula in the east intense air pressure disturbances and convective thunderstorm clouds were associated with these conditions right at the time of the event a 1 5 hpa air pressure jump was recorded at odessa and a few hours earlier in romania we have utilized a barotropic ocean numerical model to test two hypotheses 1 a tsunami like wave was generated by an air pressure disturbance propagating directly over odessa experiment 1 2 a tsunami like wave was generated by an air pressure disturbance propagating offshore approximately 200 km to the south of odessa and along the shelf break experiment 2 both experiments decisively confirm the meteorological origin of the tsunami like waves on the coast of odessa and imply that intensified long ocean waves in this region were generated via the proudman resonance mechanism while propagating over the northwestern black sea shelf the odessa tsunami of 27 june 2014 was identified as a beach meteotsunami similar to events regularly observed on the beaches of florida usa but different from the harbour meteotsunamis which occurred 1 3 days earlier in ciutadella baleares spain mazara del vallo sicily italy and vela luka croatia in the mediterranean sea despite that they were associated with the same atmospheric system moving over the mediterranean black sea region on 23 27 june 2014

dynamics on seasonal variability of eke associated with tiws in the eastern equatorial pacific ocean abstractenergetic mesoscale eddies vortices associated with tropical instability waves tiws exist in the eastern equatorial pacific ocean between 0 and 8 n this study examines the seasonal va

the root of the urals evidence from wide angle reflection seismics abstract the existence of a crustal root beneath the urals which would deflect the position of the moho by some 20 km is still largely controversial a french russian project carried out a wide angle reflection seismic experiment across the middle urals to image the moho topography along a 175 km profile running approximately east west north of ekaterinburg new data show a 6 km moho deflection beneath the central part of the orogen the moho reflectivity is variable along the section with very sharp reflections beneath the russian platform 45 km depth and fainter attenuated signals in the root zone 51 km depth even if this crustal root is not as thick as indicated by some previous speculations it makes the urals the only palaeozoic orogen in the world to show such a peculiarity a major ultramafic overload in the upper crust would partly balance the crustal root in accordance with isostatic equilibrium we finally postulate that sharp wide angle reflections from the moho can be considered indicative of a layered lower crust this would apply to the russian platform which maybe gained this structuring during the ordovician extensional regime

seismic wide angle constraints on the crust of the southern urals a wide angle seismic reflection refraction data set was acquired during spring 1995 across the southern urals to characterize the lithosphere beneath this paleozoic orogen the wide angle reflectivity features a strong frequency dependence while the lower crustal reflectivity is in the range of 6 15 hz the pmp is characterized by frequencies below 6 hz after detailed frequency filtering the seismic phases constrain a new average p wave velocity crustal model that consists of an upper layer of 5 0 6 0 km s which correlates with the surface geology 5 7 km depths at which the velocities increase to 6 2 6 3 km s 10 30 km depths at which on average the crust is characterized by velocities of 6 6 km s and finally the lower crust from 30 35 km down to the moho which has velocities ranging from 6 8 to 7 4 km s two different s wave velocity models one for the n s and one for the e w were derived from the analysis of the horizontal component recordings crustal sections of poisson s ratio and anisotropy were calculated from the velocity models the poisson s ratio increases in the lower crust at both sides of the root zone a localized 2 3 anisotropy zone is imaged within the lower crust beneath the terranes east of the root this feature is supported by time differences in the sms phase and by the particle motion diagrams which reveal two polarized directions of motion velocities are higher in the central part of the orogen than for the siberian and eastern plates these seismic recordings support a 50 56 km crustal thickness beneath the central part of the orogen in contrast to moho depths of 45 km documented at the edges of the transect the lateral variation of the pmp phase in frequency content and in waveform can be taken as evidence of different genetic origins of the moho in the southern urals

spectral analysis of tsunami waves separation of source and topography effects a new approach is proposed to separate the influence of source and topography in observed tsunami spectra and to reconstruct the initial source spectrum the method assumes a linear tide gauge response to external forcing and is based on comparative analysis of tsunami and background spectra evaluation of the ratio of tsunami to background spectra gives functional characteristics that are invariant of station location and dependent only on the source parameters three events the urup tsunami of december 22 1991 northwest pacific the hokkaido southwest okushiri tsunami of july 12 1993 sea of japan and the shikotan tsunami of october 4 1994 northwest pacific are used as examples of the proposed approach the source spectra reconstructed from the analysis of different tide gauges were found to be in good agreement with each other and with the seismological geodetic and field survey data

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

modeling the transient response of tropical convection to mesoscale sst variations abstracta cloud resolving model coupled to a mixed layer ocean with an initial 500 km wide 3 k sea surface temperature sst patch is used to demonstrate the relationship between tropical mesosca

local and remote atmospheric response to tropical instability waves a global view from space a la nina took place in the equatorial pacific in 1999 and strong tropical instability waves tiws developed causing large meanders of a sea surface temperature sst front between the equator and 3 n high resolution satellite measurements are used to describe the variability of sst surface wind velocity column integrated water vapor cloud liquid water and precipitation associated with these strong tiws in 1999 coherent ocean atmosphere patterns emerge in both the pacific and atlantic revealing rich regional characteristics in the far eastern pacific southeasterly trades strengthen weaken over positive negative sst anomalies apparently due to enhanced reduced mixing with high speed winds aloft in the central pacific we find evidence that sst induced sea level pressure changes also contribute substantially to wind fluctuations similar sst wind covariability also exists in the southern hemisphere along 2 s but the wind variability induced by unit sst anomaly is much larger than that north of the equator in the central pacific where the equatorial front is broad the northern sst pattern has a large meridional scale and reaches as far north as 6 n further to the north in the intertropical convergence zone itcz where local sst anomalies are small significant variability is found in clouds and precipitation which is further correlated with surface wind convergence in the atlantic tiw signals in sst are strongly trapped near the equator but they induce significant remote response in the itcz which takes a more southern position than its pacific counterpart and thus more susceptible to tiw influence

energy decay of the 2004 sumatra tsunami in the world ocean the catastrophic indian ocean tsunami generated off the coast of sumatra on 26 december 2004 was recorded by a large number of tide gauges throughout the world ocean this study uses gauge records from 173 sites to examine the characteristics and energy decay of the tsunami waves from this event in the indian atlantic and pacific oceans findings reveal that the decay e folding time of the tsunami wave energy within a given oceanic basin is not uniform as previously reported but depends on the absorption characteristics of the shelf adjacent to the coastal observation site and the time for the waves to reach the site from the source region in general the decay times for island and open ocean bottom stations are found to be shorter than for coastal mainland stations decay times for the 2004 sumatra tsunami ranged from about 13 h for islands in the indian ocean to 40 45 h for mainland stations in the north pacific

deep sea observations and modeling of the 2004 sumatra tsunami in drake passage 1 the 2004 sumatra tsunami was clearly recorded by two uk bottom pressure gauges dpn and dps deployed in drake passage between south america and antarctica these open ocean records were examined to estimate characteristics of the tsunami waves and to compare the results of numerical simulations with the observations maximum wave heights measured at these gauges were 4 9 cm at dpn and 7 4 cm at dps the travel times from the source area were 19 h 46 min and 19 h 39 min respectively consistent with the times obtained from the nearby coastal tide gauges the numerical model described well the frequency content amplitudes and general structure of the observed waves with only small time shifts probably related to wave dispersion effects the shifts were 15 min for dpn and 10 min for dps with the modeled waves leading the observations in each case further inspection of the simulated and observed records revealed that the identified tsunami waves are related to the second main train of waves propagating by the energy conserving route along the mid ocean ridges while the first train of waves travelling by the fastest route across the ocean remained unrecognizable in the observed dps and dpn records and undetectable in the records of coastal tide gauges because of their insignificant amplitudes compared to the background variability

coseismic slip and afterslip of the great mw 9 15 sumatra andaman earthquake of 2004 we determine coseismic and the first month postseismic deformation associated with the sumatra andaman earthquake of 26 december 2004 from near field global positioning system gps surveys in northwestern sumatra and along the nicobar andaman islands continuous and campaign gps measurements from thailand and malaysia and in situ and remotely sensed observations of the vertical motion of coral reefs the coseismic model shows that the sunda subduction mega thrust ruptured over a distance of about 1500 km and a width of less than 150 km releasing a total moment of 6 7 7 0 10 22 n m equivalent to a magnitude m w 9 15 the latitudinal distribution of released moment in our model has three distinct peaks at about 4 n 7 n and 9 n which compares well to the latitudinal variations seen in the seismic inversion and of the analysis of radiated t waves our coseismic model is also consistent with interpretation of normal modes and with the amplitude of very long period surface waves the tsunami predicted from this model fits rela tively well the altimetric measurements made by the jason and topex satellites neither slow nor delayed slip is needed to explain the normal modes and the tsunami wave the near field geodetic data that encompass both coseismic deformation and up to 40 days of postseismic deformation require that slip must have continued on the plate interface after the 500 sec long seismic rupture the postseismic geodetic moment of about 2 4 10 22 nm mw 8 8 is equal to about 30 5 of the coseismic moment release evolution of postseismic deformation is consistent with rate strengthening frictional afterslip online material summary of geodetic data used in this study

consistent estimates of tsunami energy show promise for improved early warning early tsunami warning critically hinges on rapid determination of the tsunami hazard potential in real time before waves inundate critical coastlines tsunami energy can quickly characterize the destructive potential of generated waves traditional seismic analysis is inadequate to accurately predict a tsunami s energy recently two independent approaches have been proposed to determine tsunami source energy one inverted from the deep ocean assessment and reporting of tsunamis dart data during the tsunami propagation and the other derived from the land based coastal global positioning system gps during tsunami generation here we focus on assessing these two approaches with data from the march 11 2011 japanese tsunami while the gps approach takes into consideration the dynamic earthquake process the dart inversion approach provides the actual tsunami energy estimation of the propagating tsunami waves both approaches lead to consistent energy scales for previously studied tsunamis encouraged by these promising results we examined a real time approach to determine tsunami source energy by combining these two methods first determine the tsunami source from the globally expanding gps network immediately after an earthquake for near field early warnings and then to refine the tsunami energy estimate from nearby dart measurements for improving forecast accuracy and early cancelations the combination of these two real time networks may offer an appealing opportunity for early determination of the tsunami threat for the purpose of saving more lives and early cancelation of tsunami warnings to avoid unnecessary false alarms

a comparative analysis of coastal and open ocean records of the great chilean tsunamis of 2010 2014 and 2015 off the coast of mexico the three great earthquakes off the coast of chile on 27 february 2010 maule mw 8 8 1 april 2014 iquique mw 8 2 and 16 september 2015 illapel mw 8 3 generated major transoceanic tsunamis that spread throughout the pacific ocean and were measured by numerous coastal tide gauges and open ocean dart stations statistical and spectral analyses of the tsunami waves from the events recorded on the pacific coast of mexico enabled us to estimate parameters of the waves along the coast and to compare statistical features of the events we also identified three coastal hot spots sites having maximum tsunami risk puerto angel puerto madero and manzanillo based on the joint spectral analyses of the tsunamis and background noise we have developed a method for using coastal observations to determine the underlying spectrum of tsunami waves in the deep ocean the reconstructed open ocean tsunami spectra are in close agreement with the actual tsunami spectra evaluated from direct analysis of the dart records offshore of mexico we have further used the spectral estimates to parameterize the energy of the three chilean tsunamis based on the total open ocean tsunami energy and frequency content of the individual events

the great sumatra andaman earthquake of 26 december 2004 the two largest earthquakes of the past 40 years ruptured a 1600 kilometer long portion of the fault boundary between the indo australian and southeastern eurasian plates on 26 december 2004 seismic moment magnitude mw 9 1 to 9 3 and 28 march 2005 mw 8 6 the first event generated a tsunami that caused more than 283 000 deaths fault slip of up to 15 meters occurred near banda aceh sumatra but to the north along the nicobar and andaman islands rapid slip was much smaller tsunami and geodetic observations indicate that additional slow slip occurred in the north over a time scale of 50 minutes or longer

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

introduction to tsunami science ten years after the 2004 indian ocean tsunami volume i twenty papers on the study of tsunamis and respective tsunamigenic earthquakes are included in volume ii of the pageoph topical issue tsunami science ten years after the 2004 indian ocean tsunami the papers presented in this second of two special volumes of pure and applied geophysics reflect the state of tsunami science during this time including five papers devoted to new findings specifically in the indian ocean two papers compile results from global observations and eight papers cover pacific ocean studies focusing mainly on the 2011 tohoku earthquake and tsunami remaining papers in this volume describe studies in the atlantic ocean and mediterranean sea and tsunami source studies overall the volume not only addresses the pivotal 2004 indian ocean and 2011 tohoku tsunamis but also examines the tsunami hazard posed to other critical coasts in the world

crustal root beneath the urals wide angle seismic evidence wide angle reflection and refraction data acquired as part of the urseis 995 geophysical experiment across the southern uralide orogen provide evidence for a 12 to 15 kilometer thick crustal root yielding a total crustal thickness of 55 to 58 kilometers strong reflections from the mohorovicic discontinuity moho at relatively small precritical distances suggest that the crust mantle transition beneath the crustal root is a sharp feature the derived p and s wave velocity models constrain key physical properties of the crust including the depth of the mafic rocks of the magnitogorsk volcanic arc and the existence of a lower crustal zone of possible basic rock enrichment beneath the east uralian zone

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

numerical tsunami simulation including elastic loading and seawater density stratification systemic discrepancies between observed and modeled tsunami wave speeds were previously identified for two recent major tsunamis the 2010 maule and 2011 tohoku events to account for these discrepancies we developed a numerical tsunami propagation code solving the shallow water equation and including the effects of elastic loading of the seafloor by the tsunami as well as a linear density profile in the seawater column we show here that both effects are important to explain the commonly observed difference between observations and simulations we conclude that the density variation in the seawater column affects the wave speed without changing the waveform whereas the loading effect has an effect on the wave speed and the waveform showing a negative phase before the main arrival due to the depression of the seafloor surrounding the tsunami wave the combination of both effects is needed to achieve a better match between observations and simulations

the atmospheric response to weak sea surface temperature fronts abstractthe response of the atmospheric boundary layer to fronts of sea surface temperature sst is characterized by correlations between wind stress divergence and the downwind component of the sst gradient and between the wind stress curl and the crosswind component of the sst gradient the associated regression or coupling coefficients for the wind stress divergence are consistently larger than those for the wind stress curl to explore the underlying physics the authors introduce a linearized model of the atmospheric boundary layer response to sst induced modulations of boundary layer hydrostatic pressure and vertical mixing in the presence of advection by a background ekman spiral model solutions are a strong function of the sst scale and background advection and recover observed characteristics the coupling coefficients for wind stress divergence and curl are governed by distinct physics wind stress divergence results from either large scale winds crossing the front or from a thermally direct

traveltime delay and initial phase reversal of distant tsunamis coupled with the self gravitating elastic earth systematic tsunami traveltime delays of up to 15 min relative to the numerically simulated long waves from the 2010 chilean and 2011 tohoku oki earthquakes were widely observed at deep ocean tsunamimeters enigmatic small negative phases appearing before the main peak were commonly found only at the trans oceanic locations the frequency dependence of the measured tsunami phase velocities shows reverse dispersions at long periods i e the tsunami speed becomes slower at periods beyond 1000 s this is consistent with the phase velocities of a tsunami mode coupled with a self gravitating elastic earth suggesting that the effects of compression and dilatation of seawater elastic tsunami loadings on a solid earth and the geopotential variations associated with the motion of mass during tsunami propagation are responsible for the traveltime delays and the initial negative phases simple 1 d tsunami propagation tests confirm that the reverse dispersion creates a small negative phase that precedes the main peak at large distances a new method to simulate tsunami waveforms on real ocean bathymetry that takes into account seawater compressibility the elasticity of the earth and geopotential perturbations has been developed by applying a phase correction to the simulated long waves the simulated waveforms in which phase corrections are applied for the dispersion effects accurately reproduce the observed waveforms including a small initial negative phase that appears at distant locations the traveltime difference between the observed and simulated waveforms has been decreased to less than 5 min and the waveform difference between them remarkably diminishes

on the atmospheric boundary layer over the equatorial front abstract this paper presents surface meteorological data and boundary layer profiles from a single meridional transect across the equator along 125 w collected during the pan american climate study mooring cruise in september of 1998 these observations are unique because they occurred at the start of a cold event in the eastern tropical pacific when the sst gradients along the equatorial front were near their climatological maximum in addition to the anomalous cold conditions encountered near the equator an added benefit of this limited study is the relatively high station resolution across the front the meridional minimum in sst and center of the cold tongue was 20 9 c and occurred at 0 4 n an equatorial front was located to the north where sst increased linearly to 25 5 c at 2 0 n the atmospheric boundary layer abl was stable over the cold tongue an unstable abl developed over the warm side of the front in less than 55 km the unstable abl was found at two more stations over the warm side of

real time experimental forecast of the peruvian tsunami of august 2007 for u s coastlines 1 at 23 41 utc on 15 august 2007 an offshore earthquake of magnitude 8 0 severely damaged central peru and generated a tsunami severe shaking by the earthquake collapsed buildings throughout the region and caused 514 fatalities the tsunami resulted in three casualties and a representative maximum runup height of 7 m in the near field the first real time tsunami data available came from a deep ocean tsunami detection buoy within 1 hour of tsunami generation these tsunami data were used to produce initial experimental forecasts within 2 hours of tsunami generation the far field forecasts indicated that the tsunami would not flood any of the 14 u s communities comparison with real time tide gage data showed very accurate forecasts

compensation of paleozoic orogens a comparison of the urals to the appalachians abstract the urals and appalachians are two paleozoic mountain belts with similar geologic and morphologic features we combine geophysical bouguer gravity and deep seismic sounding and geological observations from the ural mountains to test whether the surficial similarities of these paleozoic orogens extend to include deep lithospheric structure and compensation mechanism we find the combined data suggest support of the mountains by a stiff continental slab which is depressed by an effective subcrustal load in addition to the topography as has been recently proposed for the appalachians our preferred model which fits the geophysical data and predicts the presence and shape of the ural foredeep to the west of the mountains requires eastward directed underthrusting of the russian platform behaving as an elastic plate more than 50 km thick it is unlikely that an elastic plate this stiff could have resulted from conductive cooling of a thermal plate only 125 km thick the weight of the existing mountains on such an elastic plate is insufficient to produce the deflection of the moho inferred from seismic and gravity data an additional load on the elastic plate may be provided by a buried mass of similar origin to surface outcrops of dense mafic and ultramafic rocks in the eastern urals alternatively the load may represent the effect of a shallowing of the moho east of the mountains which is a remnant of a buried passive continental margin seismic data and bouguer gravity anomalies suggest that the effect of the subsurface mass anomaly is at least as great as the present day topography and that the russian plate flexurally underthrusts the urals for more than 100 km we speculate that similar effective subsurface loads may exist at younger continental orogens but are obscured by the topographic load in less eroded mountain belts

crustal seismic velocity structure of southern poland preserved memory of a pre devonian terrane accretion at the east european platform margin the updated geological and potential fields data on the east european platform margin in se poland confirm the existence of several regional units differing in ediacaran to silurian development the upper silesian block malopolska block and ysogory block all the blocks are characterized by a distinct crustal structure seen in vp velocity models obtained from the seismic refraction data of the celebration 2000 programme the first two units are interpreted as exotic terranes initially derived from avalonia type crust and ultimately accreted before the late early devonian the ysogory block is probably a proximal terrane displaced dextrally along the baltica margin the sutures between the terranes do not precisely match lateral gradients in vp models this is partly explained by a limited resolution of refraction seismic data 20 km wide interpretative window most of the difference is related however to a post accretionary tectonism mainly variscan transtension transpression the latter processes took advantage of lithospheric memory recorded earlier as zones of rheological weakness along the former suture zones the course of the east european platform margin teisseyre tornquist zone corresponds most likely to the nowe miasto zawichost fault marking the ne boundary of the proximal ysogory terrane

deep structure of the urals region and its seismicity abstract this article deals with the problem of the seismicity of the urals region taking into account peculiarities of the deep structure ascertained by deep seismic investigations along profiles with a general extent of about 10 000 km the scheme of seismotectonic zoning of the urals and the adjacent territories was compiled on the basis of data generalization on the seismicity and some determined regularities of the earthquake epicentres distribution and peculiarities of the earth s crustal structure the extent of the middle urals region with abnormal seismicity was determined three regions of abnormal seismicity were determined additionally the polar urals the prevolga the tyumen ishym regions within these regions the seismogenic zones were marked

teleseismic tomography across the middle urals lithospheric trace of an ancient continental collision abstract the urals are a major collision belt between two continental plates separated by island arcs the east european plate and the siberian plate their linear structure is preserved on a length of about 3000 km a seismic array of 61 stations has been deployed during more than 3 months on a linear profile across the middle urals north of ekaterinburg p wave travel time residuals are inverted and provide a tomographic cross section of the lithosphere on a 600 km long profile across the urals an east west asymmetry is observed both in the crust and in the lithosphere the western limit between these two different lithospheres corresponds to the western front of the uralian orogen from the surface to a depth greater than 100 km several crustal studies were performed by other teams along the same profile and we compare our teleseismic cross section to common depth point seismics to deep seismic soundings and to a wide angle reflection fan profile east of the main uralian fault the teleseismic inversion shows high velocity bodies corresponding to well known volcanic mafic and ultramafic rocks in the tagil syncline these high velocity bodies do not appear to be rooted in the lower crust as a whole the teleseismic tomogram comforts the moho imbrication model proposed by juhlin et al 1995

the 26 december 2004 sumatra tsunami analysis of tide gauge data from the world ocean part 1 indian ocean and south africa the m w 9 3 megathrust earthquake of december 26 2004 off the northwest coast of sumatra in the indian ocean generated a catastrophic tsunami that was recorded by a large number of tide gauges throughout the world ocean part 1 of our study of this event examines tide gauge measurements from the indian ocean region at sites located from a few hundred to several thousand kilometers from the source area statistical characteristics of the tsunami waves including wave height duration and arrival time are determined along with spectral properties of the tsunami records

the lithospheric trace of the iapetus suture in sw ireland from teleseismic data abstract the caledonian iapetus suture is a tectonic boundary resulting from the amalgamation in a three plate configuration of laurentia and baltica with avalonia in sw ireland seismic stations on a wide angle seismic profile crossing the postulated path of the iapetus suture have recorded a set of teleseismic events the p wave residual times for an earthquake in the aleutians end on to the line and a nuclear test in china nearly orthogonal to the line show large variations of about 0 5 s along this relatively short profile heterogeneities in the crustal structure along this profile can account for very little of the variation in residual times and most of it must originate in heterogeneities below the crust from an analysis of the residual time curves of the two teleseismic events the probable trace of the iapetus suture at depth has been found in the upper mantle between 30 and 110 km the suture is defined by a velocity contrast of about 3 and it is located just south of the shannon river estuary the interface dips steeply to the south indicating that the closure of the iapetus ocean may have involved a southward subducted slab the model obtained in sw ireland is comparable with a teleseismic tomography model across the urals this could indicate a close evolution of these two orogenies since the palaeozoic

the 21 may 2003 tsunami in the western mediterranean sea statistical and wavelet analyses we report the statistical and wavelet analyses of the 21 may 2003 tsunami produced by an mw 6 8 6 9 thrust earthquake in the western mediterranean sea using 19 tide gauge records the largest trough to crest wave height was 196 cm recorded at the sant antoni station in the lee of the incoming tsunami wave except at one station the first wave was not the largest wave at all the analyzed stations and the largest wave arrived several hours after the first arrival in addition the tsunami waves persisted for more than 1 day at most stations as the spectra of coastal tide gauge stations are strongly influenced by topographic features special care was taken here while interpreting the results of spectral and wavelet analysis our wavelet analysis shows that only a peak at around 23 min is persistent for long duration and other peaks at 14 30 45 and 60 min appeared at short durations the 23 min signal is possibly associated with the width of the source fault whereas the fault length contributed to the 45 min signal based on these dominant periods the tsunami source dimensions are estimated as 95 km 45 km the statistical and wavelet analyses performed here provide some new insights into the characteristics of the tsunami that was generated and propagated in the western mediterranean basin

double jeopardy concurrent arrival of the 2004 sumatra tsunami and storm generated waves on the atlantic coast of the united states and canada 1 a detailed analysis of over one hundred tide gauge records from the atlantic coast of north america reveals that the arrival of the 26 december 2004 sumatra tsunami on this coast coincided with the presence of tsunami like waves being generated by a major storm tracking northward along the eastern seaboard of the united states according to the tide gauge records waves from the two events coalesced along the shores of maine and nova scotia on 27 december where they produced damaging waves with heights in excess of 1 m tsunami waves were identified in almost all outer tide gauges from florida to nova scotia with maximum tsunami heights for the northern regions estimated to be 32 39 cm in the south maximum tsunami wave heights were in the range of 15 to 33 cm

the global reach of the 26 december 2004 sumatra tsunami numerical model simulations combined with tide gauge and satellite altimetry data reveal that wave amplitudes directionality and global propagation patterns of the 26 december 2004 sumatra tsunami were primarily determined by the orientation and intensity of the offshore seismic line source and subsequently by the trapping effect of mid ocean ridge topographic waveguides

the 2011 tohoku tsunami on the coast of mexico a case study the tohoku east japan earthquake of 11 march 2011 m w 9 0 generated a great trans oceanic tsunami that spread throughout the pacific ocean where it was measured by numerous coastal tide gauges and open ocean dart deep ocean assessment and reporting of tsunamis stations statistical and spectral analyses of the tsunami waves recorded along the pacific coast of mexico have enabled us to estimate the principal parameters of the waves along the coast and to compare statistical features of the tsunami with other tsunamis recorded on this coast we identify coastal hot spots manzanillo zihuatanejo acapulco and ensenada corresponding to sites having highest tsunami hazard potential where wave heights during the 2011 event exceeded 1 5 2 m and tsunami induced currents were strong enough to close port operations based on a joint spectral analysis of the tsunamis and background noise we reconstructed the spectra of tsunami waves in the deep ocean and found that with the exception of the high frequency spectral band 5 cph the spectra are in close agreement with the true tsunami spectra determined from dart bottom pressure records the departure of the high frequency spectra in the coastal region from the deep sea spectra is shown to be related to background infragravity waves generated in the coastal zone the total energy and frequency content of the tohoku tsunami is compared with the corresponding results for the 2010 chilean tsunami our findings show that the integral open ocean tsunami energy i 0 was 2 30 cm2 or approximately 1 7 times larger than for the 2010 event comparison of this parameter with the mean coastal tsunami variance 451 cm2 indicates that tsunami waves propagating onshore from the open ocean amplified by 14 times the same was observed for the 2010 tsunami the tsunami colour frequency content for the 2011 tohoku tsunami was red with about 65 of the total energy associated with low frequency waves at frequencies 35 min the red colour i e the prevalence of low frequency waves in the 2011 tohoku as well as in the 2010 chile tsunamis is explained by the large extension of the source areas in contrast the 2014 and 2015 chilean earthquakes had much smaller source areas and consequently induced bluish high frequency tsunamis

source spectrum for the algerian tsunami of 21 may 2003 estimated from coastal tide gauge data 1 on 21 may 2003 a submarine earthquake occurred near algiers producing a tsunami that propagated northward and reached the balearic islands and the levantine coast of the iberian peninsula within an hour despite that the generated tsunami was moderate sea level variations inside certain harbors at the balearic islands were significant producing severe damage to moored boats available tsunami records in the affected harbors are examined to estimate amplifications factors of arriving waves and spectral characteristics of the source comparison between background and tsunami oscillations at various sites allowed separation of the tsunami source properties from local topographic effects the fundamental period of the reconstructed source spectrum is 21 min which is in close agreement with that found by alasset et al 2006 based on modeling the tsunami initiation

improved phase corrections for transoceanic tsunami data in spatial and temporal source estimation application to the 2011 tohoku earthquake systemic travel time delays of up to 15 min relative to the linear long waves for transoceanic tsunamis have been reported a phase correction method which converts the linear long waves into dispersive waves was previously proposed to consider seawater compressibility the elasticity of the earth and gravitational potential change associated with tsunami motion in the present study we improved this method by incorporating the effects of ocean density stratification actual tsunami raypath and actual bathymetry the previously considered effects amounted to approximately 74 for correction of the travel time delay while the ocean density stratification actual raypath and actual bathymetry contributed to approximately 13 4 and 9 on average respectively the improved phase correction method accounted for almost all the travel time delay at far field stations we performed single and multiple time window inversions for the 2011 tohoku tsunami using the far field data 3 h travel time to investigate the initial sea surface displacement the inversion result from only far field data was similar to but smoother than that from near field data and all stations including a large sea surface rise increasing toward the trench followed by a migration northward along the trench for the forward simulation our results showed good agreement between the observed and computed waveforms at both near field and far field tsunami gauges as well as with satellite altimeter data the present study demonstrates that the improved method provides a more accurate estimate for the waveform inversion and forward prediction of far field data

the december 2018 anak krakatau volcano tsunami as inferred from post tsunami field surveys and spectral analysis we present analysis of the december 2018 anak krakatau tsunami in sunda strait indonesia from a combination of post tsunami field surveys bathymetric changes and spectral analysis of the tsunami tide gauge records post tsunami surveys revealed moderate tsunami height along the coast of sumatra and java with maximum surveyed runup of 13 5 m and maximum inundation distance of 330 m at small islands located close to the volcano extreme tsunami impacts were observed indicating not only a huge tsunami was generated by large amounts of collapse material which caused notable changes of seafloor bathymetry but also indicates the role of those small islands in reducing tsunami height that propagated to the mainland of indonesia our spectral analysis of tide gauge records showed that the tsunami s dominant period was 6 6 7 4 min indicating the short period nature of the 2018 sunda strait tsunami

lithosphere scale seismic image of the southern urals from explosion source reflection profiling explosive source deep seismic reflection data from the southern ural mountains of central russia provided a lithosphere scale image of the central eurasian plate that reveals deep reflections 35 to 45 seconds in travel time 130 to 170 kilometers deep from the mantle the data display laterally variable reflectivity at the base of the crust that deepens beneath the central part of the profile documenting a crustal thickness of 55 to 60 kilometers beneath the axis of the orogen these data provide an image of the structure of the crust and underlying mantle lithosphere in a preserved collisional orogen perhaps to the base of the lithosphere

high resolution teleseismic tomography of upper mantle structure using an a priori three dimensional crustal model summary the effect of an a priori known 3 d crustal model in teleseismic tomography of upper mantle structure is investigated we developed a 3 d crustal p wave velocity model for the greater alpine region encompassing the central and western alps and the northern apennines to estimate the crustal contribution to teleseismic traveltimes the model is constructed by comparative use of published information from active and passive seismic surveys the model components are chosen to represent the present large scale alpine crustal structure and for their significant effect on the propagation of seismic wavefields they are first order structures such as the crust mantle boundary sedimentary basins and the high velocity ivrea body teleseismic traveltime residuals are calculated for a realistic distribution of azimuths and distances by coupling a finite difference technique to the iasp91 traveltime tables residuals are produced for a synthetic upper mantle model featuring two slab structures and the 3 d crustal model on top of it the crustal model produces traveltime residuals in the range between 0 7 and 1 5 s that vary strongly as a function of backazimuth and epicentral distance we find that the non linear inversion of the synthetic residuals without correcting for the 3 d crustal structure erroneously maps the crustal anomalies into the upper mantle correction of the residuals for crustal structure before inversion properly recovers the synthetic slab structures placed in the upper mantle we conclude that with the increasing amount of high quality seismic traveltime data correction for near surface structure is essential for increasing resolution in tomographic images of upper mantle structure

effects of bathymetry on tsunami propagation application of ray tracing to tsunamis ray tracing of seismic surface waves is applied to tsunami propagation to examine bathymetric effect along its propagation path computations are made for trans pacific tsunamis and for near field tsunamis in the japan sea for tsunamis across the pacific ocean the comparison to a uniform ocean shows that focusing and defocusing due to bathymetry are significant for some combinations of source and receiver for example the refraction of rays is predominant at the east pacific rise for the tsunami from chile the tsunamis in the japan sea are strongly affected by the shallow yamato rise the predicted arrival time and amplitude distribution generally agree with the observations from an actual tsunami since the computation can be made very quickly the method is useful for preliminary analysis of tsunami propagation such as in an operational warning system or in the determination of computational area for finite difference computation

history and features of trans oceanic tsunamis and implications for paleo tsunami studies abstract far field tsunamis and their features as well as methods to quantify trans oceanic tsunamis are reviewed with examples of instrumental and historical data tsunamis from the 1854 nankai earthquakes the 1946 aleutian tsunami earthquake the 1960 and 2010 chile earthquakes as well as the 2011 tohoku earthquake were recorded around the pacific ocean the 1883 krakatoa volcanic eruption caused volcanic tsunami in the indian ocean and meteotsunami in the pacific ocean the 2004 indian ocean tsunami was also recorded in the pacific ocean when a tsunami amplitude is larger than that of ocean tides which usually requires the parent earthquake to be gigantic mw 9 it can cause damage and may be historically documented the trans pacific tsunamis described in historical documents include those from the 1700 cascadia earthquake the 1730 1751 1837 and 1877 earthquakes off chile and the 1687 and 1868 earthquakes off peru the tsunami record in japan from the 1586 peru earthquakes was found to be incorrect and should be discounted the tsunami magnitude scale relates the tsunami heights to the earthquake size tsunami travel time can be computed from actual bathymetry and the tsunami ray tracing provides relative amplitudes due to focusing defocusing caused by irregular bathymetry numerical computations from fault models produce tsunami amplitudes and waveforms and indicate strong directivity due to strike of fault or orientation of subduction zones far field tsunamis are often long lasting due to multiple reflections across the basin or on continental shelf or due to resonance in bays harbors these features would provide important criteria to estimate tsunami sources from paleo tsunami data

the 2017 mexico tsunami record numerical modeling and threat assessment in costa rica an mw 8 2 earthquake and tsunami occurred offshore the pacific coast of mexico on 2017 09 08 at 04 49 utc costa rican tide gauges have registered a total of 21 local regional and far field tsunamis the quepos gauge registered 12 tsunamis between 1960 and 2014 before it was relocated inside a harbor by late 2014 where it registered two more tsunamis this paper analyzes the 2017 mexico tsunami as recorded by the quepos gauge it took 2 h for the tsunami to arrive to quepos with a first peak height of 9 35 cm and a maximum amplitude of 18 8 cm occurring about 6 h later as a decision support tool this tsunami was modeled for quepos in real time using commit community model interface for tsunami with the finer grid having a resolution of 1 arcsec 30 m however the model did not replicate the tsunami record well probably due to the lack of a finer and more accurate bathymetry in 2014 the national tsunami monitoring system of costa rica sinamot was created acting as a national tsunami warning center the occurrence of the 2017 mexico tsunami raised concerns about warning dissemination mechanisms for most coastal communities in costa rica due to its short travel time

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

potential mass movements on the palinuro volcanic chain southern tyrrhenian sea italy and consequent tsunami generation abstract the palinuro volcanic chain pvc is located about 80 km offshore the campania region italy in the southern sector of the tyrrhenian sea the chain consists of 15 volcanic edifices aligned in an e w direction with two distinct major seamounts palinuro and glabro they cover a 90 km long and 20 km wide area with a present day volume of 2700 km3 palinuro volcanism emplaced between 0 8 and 0 3 ma although shallow seismicity and hydrothermalism indicate an ongoing volcanic activity a geomorphological analysis of the volcanic chain and data from a multichannel seismic profile reveal large volumes of buried chaotic material suggesting gravity mass sliding from the volcano flanks and slide scars a stability analysis of the palinuro flanks has been carried out to determine the sectors potentially prone to sliding in case of shallow volcanic earthquakes landslides are simulated by adopting a scenario based approach tsunamis induced by these mass movements and their propagation across the tyrrhenian sea are modeled results suggest that shallow earthquakes m 4 6 4 8 are able to destabilize the flanks of the volcanic chain generating slope failures sliding volumes in the order of 1 5 km3 and 2 4 km3 may induce waves as high as 1 5 and 6 m respectively along the peri tyrrhenian coast our results underline the need for further investigations on the stability of the submarine volcanoes of the tyrrhenian basin these volcanoes are still poorly known although their instability could trigger large tsunamis along the southern italy coastal sectors our recommendation is that multiparamertic monitoring networks on pvc and periodic oceanic cruises should be put into action and further that a systematic evaluation of the tsunami hazard related to possible sliding phenomena on the flanks of the tyrrhenian seamounts should be performed

observations of coupling between surface wind stress and sea surface temperature in the eastern tropical pacific satellite measurements of surface wind stress from the quikscat scatterometer and sea surface temperature sst from the tropical rainfall measuring mission microwave imager are analyzed for the three month period 21 july 20 october 1999 to investigate ocean atmosphere coupling in the eastern tropical pacific oceanic tropical instability waves tiws with periods of 20 40 days and wavelengths of 1000 2000 km perturb the sst fronts that bracket both sides of the equatorial cold tongue which is centered near 1 8s to the east of 1308w these perturbations are characterized by cusp shaped features that propagate systematically westward on both sides of the equator the space time structures of these sst perturbations are reproduced with remarkable detail in the surface wind stress field the wind stress divergence is shown to be linearly related to the downwind component of the sst gradient with a response on the south side of the cold tongue that is about twice that on the north side the wind stress curl is linearly related to the crosswind component of the sst gradient with a response that is approximately half that of the wind stress divergence response to the downwind sst gradient the perturbed sst and wind stress fields propagate synchronously westward with the tiws this close coupling between sst and wind stress supports the wallace et al hypothesis that surface winds vary in response to sst modification of atmospheric boundary layer stability

images of lithospheric heterogeneities in the armorican segment of the hercynian range in france the armorican massif is located in western france it is a part of the hercynian range formed in several phases of se nw compression from devonian to carboniferous time ca 400 300 ma the main tectonic features are the north and south armorican shear zones with wnw ese strike in the framework of the geofrance3d program we have installed 35 seismological stations along two ns lines crossing the main hercynian wnw ese fault systems the data set collected during the experiment allows us to compute a 3d p velocity model and to map s wave seismic anisotropy at depth using teleseismic shear waves splitting measurements the south armorican shear zone sasz is characterized by a strong 4 5 velocity contrast and a fast shear wave azimuth parallel to its strike the north armorican shear zone nasz does not show any significant lithospheric signature the tomographic image and anisotropy results suggest that the armorican lithosphere consists of the juxtaposition of distinct lithospheric blocks assembled in a subduction type process predating the hercynian orogeny d 2002 elsevier science b v all rights reserved