depositional evolution and sequence stratigraphy of the shelf and slope area off south gabon west africa abstract the tertiary succession off south gabon is divided into stratigraphic sequences the study includes interpretation of seismic data and data from seven wells within the study area covering 26 000 km2 four paleogene sequences p1 p4 are recognized within the danian to earliest early ypresian time interval there was a major hiatus from the middle eocene to the early miocene in the study area six sequences n1 n6 are identified in the neogene n1 n4 lower and middle miocene and n5 and n6 probably upper miocene to recent the danian and thanetian sequences p1 p3 are separated by type 2 sequence boundaries and the most widespread flooding of the area occurred at the danian thanetian transition within sequence p2 the boundary between p3 and p4 close to the thanetian ypr sian transition is probably of type 1 the paleocene sequences consist of transgressive systems tracts and highstand systems tracts the lower miocene sequence n1 was formed mainly by progradation of the shelf as a result of high sediment supply and had a tectonic origin the middle miocene sequence boundaries are characterized by deep erosion e g canyon formation into the substratum and thus are type 1 sequence boundaries the middle miocene sequences n2 n4 consist of lowstand systems tracts transgressive systems tracts early part and late highstand systems tracts the upper miocene to holocene interval n5 n6 could not be subdivided because the deposits are relatively thin the tertiary mainly siliciclastic sediments are mainly fine grained sediments though sandstones are identified at sequence boundaries of danian to ypresian ages sandstones are also inferred to have been deposited during the early fill of canyons and basinward in the middle miocene the processes involved in the formation of these sequences is thought to be a combination of basin type tectonics sediment supply and sea level changes curves of relative sea level and eustatic sea level were constructed for the studied interval and these curves are compared with earlier published sea level curves for the tertiary

crustal stress determination from boreholes and rock cores fundamental principles abstract obtaining quantitative information on the state of stress in the crust can only be accomplished by accessing the zone of interest by drilling the borehole cavity however disrupts the virgin stress state by concentrating stresses in predictable patterns with a number of consequences at sufficiently low stress magnitudes the concentrated stresses amplify the elastic anisotropy azimuthally around the borehole because the elastic properties of most rocks depend nonlinearly on stress at higher levels the stresses damage then fracture the rock near the wellbore wall or within a growing core stub indeed almost all of the borehole techniques indirectly measure stress through these manifestations of the concentrated stresses this contribution reviews at a fundamental level the concentration of stresses by the borehole the effects on the materials in the borehole s vicinity and how these are used to infer stress states stress concentrations applied to rocks which are generally nonlinear elastic materials induce both radial and azimuthal variations in elastic wave speeds near the borehole that can be used to infer stress directions from advanced acoustic logging methods hydraulic fractures initiate propagate and remain propped open by measured pressures that can be interpreted with knowledge of the stress concentrations to obtain quantitative stress magnitudes at higher stress levels the rock fails producing borehole breakouts or drilling induced tensile fractures both of which are indicative of stress directions and can be used to constrain stress magnitudes similarly the various styles of drilling induced core fractures indicate both stress directions and the faulting environment encountered unfortunately no method currently allows for complete determination of the stress tensor using a number of different but complementary techniques is necessary to best constrain in situ stress states

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

method to determine appropriate source models of large earthquakes including tsunami earthquakes for tsunami early warning in central america large earthquakes such as the mw 7 7 1992 nicaragua earthquake have occurred off the pacific coasts of el salvador and nicaragua in central america and have generated distractive tsunamis along these coasts it is necessary to determine appropriate fault models before large tsunamis hit the coast in this study first fault parameters were estimated from the w phase inversion and then an appropriate fault model was determined from the fault parameters and scaling relationships with a depth dependent rigidity the method was tested for four large earthquakes the 1992 nicaragua tsunami earthquake mw7 7 the 2001 el salvador earthquake mw7 7 the 2004 el astillero earthquake mw7 0 and the 2012 el salvador nicaragua earthquake mw7 3 which occurred off el salvador and nicaragua in central america the tsunami numerical simulations were carried out from the determined fault models we found that the observed tsunami heights run up heights and inundation areas were reasonably well explained by the computed ones therefore our method for tsunami early warning purpose should work to estimate a fault model which reproduces tsunami heights near the coast of el salvador and nicaragua due to large earthquakes in the subduction zone

a methodology for near field tsunami inundation forecasting application to the 2011 tohoku tsunami existing tsunami early warning systems in the world can give either one or a combination of estimated tsunami arrival times heights or qualitative tsunami forecasts before the tsunami hits near field coastlines a future tsunami early warning system should be able to provide a reliable near field tsunami inundation forecast on high resolution topography within a short time period here we describe a new methodology for near field tsunami inundation forecasting in this method a precomputed tsunami inundation and precomputed tsunami waveform database is required after information about a tsunami source is estimated tsunami waveforms at nearshore points can be simulated in real time a scenario that gives the most similar tsunami waveforms is selected as the site specific best scenario and the tsunami inundation from that scenario is selected as the tsunami inundation forecast to test the algorithm tsunami inundation along the sanriku coast is forecasted by using source models for the 2011 tohoku earthquake estimated from gps w phase or offshore tsunami waveform data the forecasting algorithm is capable of providing a tsunami inundation forecast that is similar to that obtained by numerical forward modeling but with remarkably smaller cpu time the time required to forecast tsunami inundation in coastal sites from the sendai plain to miyako city is approximately 3 min after information about the tsunami source is obtained we found that the tsunami inundation forecasts from the 5 min gps 5 min w phase 10 min w phase fault models and 35 min tsunami source model are all reliable for tsunami early warning purposes and quantitatively match the observations well although the latter model gives tsunami forecasts with highest overall accuracy the required times to obtain tsunami forecast from the above four models are 8 min 9 min 14 min and 39 min after the earthquake respectively or in other words 3 min after receiving the source model this method can be useful in developing future tsunami forecasting systems with a capability of providing tsunami inundation forecasts for locations near the tsunami source area

the effect of sample disturbance on laboratory properties of lac du bonnet granite laboratory properties of lac du bonnet granite samples collected at depths ranging from near surface to 1000 m were established the laboratory properties indicated that either the in situ properties were changing with depth or the samples were changing with depth comparison of p wave velocities in the samples and in situ confirmed the latter i e sample disturbance was affecting the laboratory properties the strength of the damaged samples indicated that sample disturbance affected the cohesion of the material not the frictional properties and that the cohesion loss cannot be accounted for by applying a confining stress sample disturbance started to affect the laboratory properties of lac du bonnet granite when the maximum far field in situ stress exceeded about 10 of the unconfined compression strength key words sample disturbance core discing cohesion brittle rocks damage microcracks stress dependent young s modulus

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

source inversion of w phase speeding up seismic tsunami warning w phase is a long period phase arriving before s wave it can be interpreted as superposition of the fundamental first second and third overtones of spheroidal modes or rayleigh waves and has a group velocity from 4 5 to 9 km s 1 over a period range of 100 1000 s the amplitude of long period waves better represents the tsunami potential of an earthquake because of the fast group velocity of w phase most of w phase energy is contained within a short time window after the arrival of the p wave at a distance of 50 w phase energy is contained within 23 min after the origin time which is the distinct advantage of using w phase for rapid tsunami warning purposes we use a time domain deconvolution method to extract w phases from the broad band records of global seismic networks the bandwidth of w phase is approximately from 0 001 to 0 01 hz and we bandpass filter the data from 0 001 to 0 005 hz in most cases having extracted w phase from the vertical component records we perform a linear inversion using a point source to determine mw and the source mechanism for several large earthquakes including the 2004 sumatra andaman earthquake the 2005 nias earthquake the 2006 kuril is earthquake and the 2007 sumatra earthquake w phase inversion yields reliable solutions and holds promise of the use of w phase for rapid assessment of tsunami potential

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

hoek brown parameters for predicting the depth of brittle failure around tunnels a review of underground openings excavated in varying rock masstypes and conditions indicates that the initiation of brittlefailure occurs when the damage index di expressed as theratio of the maximum tangential boundary stress to the laboratoryunconfined compressive strength exceeds approx0 4 when thedamage index exceeds this value the depth of brittle failure around a tunnel can be estimated by using a strengthenvelope based solely on cohesion which in terms of thehoek brown parameters implies that m 0 it is proposed that inthe brittle failure process peak cohesion and friction are notmobilized together and that around underground openings thebrittle failure process is dominated by a loss of the intrinsiccohesion of the rock mass such that the frictional strengthcomponent can be ignored for estimating the depth of brittlefailure an essential component in designing support for theopening case histories were analyzed using the hoek brownfailure criterion with traditional frictional parameter

scaling relations of earthquake source parameter estimates with special focus on subduction environment abstract earthquake rupture length and width estimates are in demand in many seismological applications earthquake magnitude estimates are often available whereas the geometrical extensions of the rupture fault mostly are lacking therefore scaling relations are needed to derive length and width from magnitude most frequently used are the relationships of wells and coppersmith 1994 derived on the basis of a large dataset including all slip types with the exception of thrust faulting events in subduction environments however there are many applications dealing with earthquakes in subduction zones because of their high seismic and tsunamigenic potential there are no well established scaling relations for moment magnitude and length width for subduction events within this study we compiled a large database of source parameter estimates of 283 earthquakes all focal mechanisms are represented but special focus is set on large subduction zone events in particular scaling relations were fitted with linear least square as well as orthogonal regression and analyzed regarding the difference between continental and subduction zone oceanic relationships additionally the effect of technical progress in earthquake parameter estimation on scaling relations was tested as well as the influence of different fault mechanisms for a given moment magnitude we found shorter but wider rupture areas of thrust events compared to wells and coppersmith 1994 the thrust event relationships for pure continental and pure subduction zone rupture areas were found to be almost identical the scaling relations differ significantly for slip types the exclusion of events prior to 1964 when the worldwide standard seismic network was established resulted in a remarkable effect on strike slip scaling relations the data do not show any saturation of rupture width of strike slip earthquakes generally rupture area seems to scale with mean slip independent of magnitude the aspect ratio l w however depends on moment and differs for each slip type

comparing source inversion techniques for gps based local tsunami forecasting a case study for the april 2014 m8 1 iquique chile earthquake

w phase inversion and tsunami inundation modeling for tsunami early warning case study for the 2011 tohoku event centroid moment tensor solutions for the 2011 tohoku earthquake are determined by w phase inversions using 5 and 10 min data recorded by the full range seismograph network of japan f net by a scaling relation of moment magnitude to rupture area and an assumption of rigidity of 4 1010 n m 2 simple rectangular earthquake fault models are estimated from the solutions tsunami inundations in the sendai plain minamisanriku rikuzentakata and taro are simulated using the estimated fault models then the simulated tsunami inundation area and heights are compared with the observations even the simulated tsunami heights and inundations from the w phase solution that used only 5 min data are considerably similar to the observations the results are improved when using 10 min of w phase data these show that the w phase solutions are reliable to be used for tsunami inundation modeling furthermore the technique that combines w phase inversion and tsunami inundation modeling can produce results that have sufficient accuracy for tsunami early warning purposes

estimated seismic source parameters for 2019 magnitude 7 6 papua new guinea earthquake on 14 may 2019 a major mw 7 6 earthquake struck eastern papua new guinea causing a tsunami warning that was later canceled the last major rupture in the region was a 2000 mw 8 0 event which resulted in massive horizontal land movements of up to several meters and a series of aftershocks with primarily thrust mechanisms and caused a damaging tsunami seismic methods for characterizing the source process were applied vertical components of the long period p waves from 35 stations of the global seismic network with even azimuthal coverage were adopted in the inversions first the focal mechanism solution was retrieved after the earthquake from the inverted results as well as aftershock distribution the causative fault of the great png earthquake was confirmed to be a fault of strike 316 dip 84 and rake 0 indicating that the earthquake was a left lateral strike slip event then to clearly understand the spatiotemporal evolutionary process of the source rupture of the earthquake far field body wave data were collected and the source rupture process of this earthquake was studied using the finite fault inversion method a finite fault model was estabished with length and width of 152 and 32 km respectively and we set the initial seismic source parameters referring to the center of the focal mechanism solution this was estimated by the focal mechanism solutions of defferent studies referring to different focal mechanism solutions we found that the focal mechanism solution determined by global centroid moment tensor catalog was not appropriate inversion results indicated that the seismic moment was 3 63 1020 nm mw 7 6 and the source duration was 40 s the rupture propagated mainly toward the northwest in an asymmetrical bilateral mode with a maximum slip of 13 2 m and a large scale slip patch strongly ruptured to the surface the study of coulomb stress changes suggested that the png earthquake may trigger a thrust type rupture in the new britain trench which has the potential to trigger a tsunami

core disking and its relationship with stress magnitude for lac du bonnet granite abstract core disking is an indicator of elevated stress magnitudes disked cores from boreholes drilled from underground excavations in massive unfractured granite where the stress magnitudes are known with confidence were used to establish a relationship between core disk thickness and the stress magnitude relationships were established for three disk thickness categories 1 thin t d 0 2 2 medium 0 2 t d 0 4 and 3 thick 0 4 t d 2 2 and partial disking the data suggests that core disking initiates when the maximum principal stress normalized to the tensile strength is 6 5

pre computed tsunami inundation database and forecast simulation in pelabuhan ratu indonesia we built a pre computed tsunami inundation database in pelabuhan ratu one of tsunami prone areas on the southern coast of java indonesia which can be employed for a rapid estimation of tsunami inundation during an event the pre computed tsunami waveforms and inundations are from a total of 340 scenarios ranging from 7 5 to 9 2 in moment magnitude scale mw including simple fault models of 208 thrust faults and 44 tsunami earthquakes on the plate interface as well as 44 normal faults and 44 reverse faults in the outer rise region using our tsunami inundation forecasting algorithm neartif we could rapidly estimate the tsunami inundation in pelabuhan ratu for three different hypothetical earthquakes the first hypothetical earthquake is a megathrust earthquake type mw 9 0 offshore sumatra which is about 600 km from pelabuhan ratu to represent a worst case event in the far field the second hypothetical earthquake mw 8 5 is based on a slip deficit rate estimation from geodetic measurements and represents a most likely large event the third hypothetical earthquake is a tsunami earthquake type mw 8 1 which often occurs south of java we compared the tsunami inundation maps produced by the neartif algorithm with results of direct forward inundation modeling for the hypothetical earthquakes the tsunami inundation maps produced from both methods are similar for the three cases however the tsunami inundation map from the inundation database can be obtained in much shorter time 1 min than the one from a forward inundation modeling 40 min these indicate that the neartif algorithm based on pre computed inundation database is reliable and useful for tsunami warning purposes this study also demonstrates that the neartif algorithm can work well though the earthquake source is located outside the area of fault model database because it uses a time shifting procedure for the best fit scenario searching

dispersion and nonlinear effects in the 2011 tohoku oki earthquake tsunami this study reveals the roles of the wave dispersion and nonlinear effects for the 2011 tohoku oki earthquake tsunami we conducted tsunami simulations based on the nonlinear dispersive equations with a high resolution source model the simulations successfully reproduced the waveforms recorded in the offshore deep sea and focal areas the calculated inundation area coincided well with the actual inundation for the sendai plain which was the widest inundation area during this event by conducting sets of simulations with different tsunami equations we obtained the followings insights into the wave dispersion nonlinear effects and energy dissipation for this event although the wave dispersion was neglected in most studies the maximum amplitude was significantly overestimated in the deep sea if the dispersion was not included the waveform observed at the station with the largest tsunami height 2 m among the deep ocean stations also verified the necessity of the dispersion it is well known that the nonlinear effects play an important role for the propagation of a tsunami into bays and harbors additionally nonlinear effects need to be considered to accurately model later waves even for offshore stations in particular including nonlinear terms rather than the inundation was more important when precisely modeling the waves reflected from the coast

the relationship between submarine canyon fill and sea level change an example from middle miocene offshore gabon west africa abstract a series of middle miocene submarine canyons has been mapped in offshore gabon west africa using a combination of seismic facies analysis and well information three distinct seismic facies are recognized in the canyon fill the evolution of these facies is inferred to be related to sea level change during sea level lowstand deposition was characterized by lateral accretion on the southern canyon wall whilst progressive erosion occurred on the northern wall this depositional pattern was controlled by a local coast parallel current that flowed northwestwards along west africa during the middle miocene as relative sea level rose the erosion on the northern wall ceased and the canyons were filled by sediments showing an aggradational stratal pattern finally during the early part of the transgression the canyons were filled with horizontal or subhorizontal sedimentary strata the sedimentary fill is thought to consist of alternating sands and mud within its lower part but as relative sea level rose clayey sediments gradually dominated the canyon fill

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

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

w phase source inversion for moderate to large earthquakes 1990 2010 rapid characterization of the earthquake source and of its effects is a growing field of interest until recently it still took several hours to determine the first order attributes of a great earthquake e g m w 7 5 even in a well instrumented region the main limiting factors were data saturation the interference of different phases and the time duration and spatial extent of the source rupture to accelerate centroid moment tensor cmt determinations we have developed a source inversion algorithm based on modelling of the w phase a very long period phase 100 1000 s arriving at the same time as the p wave the purpose of this work is to finely tune and validate the algorithm for large to moderate sized earthquakes using three components of w phase ground motion at teleseismic distances to that end the point source parameters of all m w 6 5 earthquakes that occurred between 1990 and 2010 815 events are determined using federation of digital seismograph networks global seismographic network broad band stations and sts1 global virtual networks of the incorporated research institutions for seismology data management center for each event a preliminary magnitude obtained from w phase amplitudes is used to estimate the initial moment rate function half duration and to define the corner frequencies of the passband filter that will be applied to the waveforms starting from these initial parameters the seismic moment tensor is calculated using a preliminary location as a first approximation of the centroid a full cmt inversion is then conducted for centroid timing and location determination comparisons with harvard and global cmt solutions highlight the robustness of w phase cmt solutions at teleseismic distances the differences in m w rarely exceed 0 2 and the source mechanisms are very similar to one another difficulties arise when a target earthquake is shortly e g within 10 hr preceded by another large earthquake which disturbs the waveforms of the target event to deal with such difficult situations we remove the perturbation caused by earlier disturbing events by subtracting the corresponding synthetics from the data the cmt parameters for the disturbed event can then be retrieved using the residual seismograms we also explore the feasibility of obtaining source parameters of smaller earthquakes in the range 6 0 mw 6 5 results suggest that the w phase inversion can be implemented reliably for the majority of earthquakes of mw 6 or larger

multi data type source estimation for the 1992 flores earthquake and tsunami we revisit the source of the 1992 flores earthquake and tsunami using finite fault inversion we simultaneously invert teleseismic body and surface waves together with coseismic uplift subsidence datasets we then verify the inverted source against tsunami run up heights along the northern coast of flores island and the only tide gauge recording of the tsunami our preferred source model provides a good fit to all the datasets whereas previous models only explained a subset of the available data we show that the fault geometry implies segmentation of the back arc thrust system in the eastern sunda arc

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

near field tsunami inundation forecast using the parallel tunami n2 model application to the 2011 tohoku oki earthquake combined with source inversions to contribute to tsunami early warning systems we investigated the currently achievable speed of tsunami inundation simulations on a parallel computer as well as the benefits of high resolution and faster than real time inundation predictions we found that a 5 m resolution inundation simulation can be 75 times faster than real time requiring only 1 5 min to overview the inundation situation in sendai city for the 2011 tohoku tsunami we developed a novel parallel tsunami model based on the well known tunami n2 model and achieved 9 17 tera floating point operations per second flops on 9469 cpu cores the present model can accurately hindcast the observed inundated regions of the 2011 tohoku tsunami using tsunami source estimations of the tfish and tfish rapid algorithms which can be instantly derived from real time observation data the present high resolution predictions can provide clear images of imminent hazards disasters and can provide guidance for appropriate evacuation actions

reply to oligocene to holocene sediment drifts and bottom currents on the slope of gabon continental margin west africa consequences for sedimentation and southeast atlantic upwelling sedimentary geology 128 179 199 1999