quasi real time fault model estimation for near field tsunami forecasting based on rtk gps analysis application to the 2011 tohoku oki earthquake mw 9 0 1 real time crustal deformation monitoring is extremely important for achieving rapid understanding of actual earthquake scales because the measured permanent displacement directly gives the true earthquake size seismic moment mw information which in turn provides tsunami forecasting we have developed an algorithm to detect estimate static ground displacements due to earthquake faulting from real time kinematic gps rtk gps time series the new algorithm identifies permanent displacements by monitoring the difference of a short term average sta to a long term average lta of the gps time series we assessed the noise property and precision of the rtk gps time series with various baseline length conditions and orbits and discerned that the real time ephemerides based on the international gnss service igs are sufficient for crustal deformation monitoring with long baselines up to 1 000 km we applied the algorithm to data obtained in the 2011 off the pacific coast of tohoku earthquake mw 9 0 to test the possibility of coseismic displacement detections and further we inverted the obtained displacement fields for a fault model the inversion estimated a fault model with mw 8 7 which is close to the actual mw of 9 0 within five minutes from the origin time once the fault model is estimated tsunami waveforms can be immediately synthesized using pre computed tsunami green s functions the calculated waveforms showed good agreement with the actual tsunami observations both in arrival times and wave heights suggesting that the rtk gps data by our algorithm can provide reliable rapid tsunami forecasting that can complement existing tsunami forecasting systems based on seismic observations

hydroxyl oh production on airless planetary bodies evidence from h d ion beam experiments abstract the hypothesis that bombardment of lunar soil with solar wind protons might form hydroxyl oh and perhaps hoh has been tested by experiments with apollo 16 highlands and apollo 17 mare soils pre dried soils 500 c were bombarded with 1 1 kev protons and deuterons and provide unambiguous evidence for the formation of oh or od in both samples this hypothesis further predicts the formation of hydroxyl oh on other airless planetary asteroidal bodies with a sufficient solar wind flux deuteron implantation of unaltered lunar soils and a heat treated plagioclase specimen cause simultaneous oh depletion and od formation ion bombardment of lunar soils simulates the dynamic process of hydroxyl formation and may also deplete intrinsic oh thereby effectively contributing to the day night diurnal variability of oh reported by sunshine et al 2009 our results emphasize the need to use lunar soils with space weathered exteriors in laboratory simulations of the solar wind infrared spectra of hydrogen ion beam implanted soils are similar to spectra obtained at relab brown univ and to those observed by remote sensing confirming the solar wind hypothesis

understanding the lunar surface and space moon interactions the surface of the moon is a critical boundary that shapes our understanding of the moon as a whole all geologic mapping and remote sensing techniques utilize only the outermost portion of the moon before leaving the moon for study in our laboratories all lunar samples that have been studied existed at or very near the surface with the exception of the deeply probing geophysical techniques our understanding of the interior of the moon is derived from surficial but not superficial information coupled with boundary of the lunar crust it is the lower boundary layer of the tenuous lunar atmosphere and constitutes both a source and a sink for atmospheric gases the surface is also where the moon interacts with the space environment causing changes in the physical nature of lunar materials and provides a laboratory for the study of processes that occur on all airless bodies the data obtained remotely by the galileo clementine and lunar prospector missions as well as data derived from lunar meteorites have resulted in major changes to our understanding of global distributions of chemistry and rocks this chapter summarizes the current understanding of this critical interface the surface of the moon in its role as the lower boundary of the lunar atmosphere the upper boundary of the crust and the window through which we view through remote sensing the composition of the crust and the history of the moon in this post lunar prospector time the view of the moon has changed lending new perspectives to lunar samples and lunar processes but the new view will likely remain in flux as we continue to digest the results from these recent space missions and move forward to a new era of lunar exploration despite the freshness of our perspective this is an important moment to capture

sources and physical processes responsible for oh h2o in the lunar soil as revealed by the moon mineralogy mapper m3 1 analysis of two absorption features near 3 m in the lunar reflectance spectrum observed by the orbiting m3 spectrometer and interpreted as being due to oh and h2o is presented and the results are used to discuss the processes producing these molecules this analysis focuses on the dependence of the absorptions on lunar physical properties including composition illumination latitude and temperature solar wind proton induced hydroxylation is proposed as the creation process and its products could be a source for other reported types of hydrogen rich material and water the irregular and damaged fine grained lunar soil seems especially adapted for trapping solar wind protons and forming oh owing to abundant dangling oxygen bonds the m3 data reveal that the strengths of the two absorptions are correlated and widespread and both are correlated with lunar composition but in different ways feldspathic material seems richer in oh these results seem to rule out water from the lunar interior and cometary infall as major sources there appear to be correlations of apparent band strengths with time of day and lighting conditions however thermal emission from the moon reduces the apparent strengths of the m3 absorptions and its removal is not yet completely successful further many of the lunar physical properties are themselves intercorrelated and so separating these dependencies on the absorptions is difficult due to the incomplete m3 data set this process should also operate on other airless silicate surfaces such as mercury and vesta which will be visited by the dawn spacecraft in mid 2011

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

apollo sample 70051 and high and low ti lunar soil simulants mls 1a and jsc 1a implications for future lunar exploration 1 plans for establishment of a manned lunar base make it imperative that considerable research be performed on the use of lunar rocks and soil for in situ resource utilization isru samples and simulants of lunar soil must be established for these studies we present here the bulk and mineral chemistries of unusual apollo 17 sample 70051 the 80 of particles 50 m and a constrained range of particle sizes 50 of particles are 50 100 m in size when compared to typical apollo 17 soils e g 71501 1 has 20 of particles in the 50 100 m range plagioclase present in rock fragments and as mineral fragments up to sizes 1 mm is the main phase present 50 5 vol simulant jsc 1a has a chemistry that is atypical for most of the moon and contains 49 3 vol glass simulant mls 1a resembles the feo tio2 and al2o3 contents of mare basalt soils both lunar soil simulants have specific properties for certain in situ resource utilization studies however neither fully matches both the physical and chemical characteristics of lunar soil sample 70051 as a 1 4 kg haphazard mixture of lunar soil particles is probably the best of the apollo soil samples to be allocated for various isru investigations where the uniqueness of lunar soils is deemed a necessity for study

effect of depth dependent shear modulus on tsunami generation along subduction zones estimates of the initial size of tsunamis generated by subduction zone earthquakes are significantly affected by the choice of shear modulus at shallow depths analysis of over 360 circum pacific subduction zone earthquakes indicates that for a given seismic moment source duration increases significantly with decreasing depth bilek and lay 1998 1999 under the assumption that stress drop is constant the increase of source duration is explained by a 5 fold reduction of shear modulus from depths of 20 km to 5 km this much lower value of shear modulus at shallow depths in comparison to standard earth models has the effect of increasing the amount of slip estimated from seismic moment determinations thereby increasing tsunami amplitude the effect of using depth dependent shear modulus values is tested by modeling the tsunami from the 1992 nicaraguan tsunami earthquake using a previously determined moment distribution ihmle 1996a we find that the tide gauge record of this tsunami is well matched by synthetics created using the depth dependent shear modulus and moment distribution because excitation of seismic waves also depends on elastic heterogeneity it is important particularly for the inversion of short period waves that a consistent seismic tsunami shear modulus model be used for calculating slip distributions

hypothetical real time gnss modeling of the 2016 mw 7 8 kaikōura earthquake perspectives from ground motion and tsunami inundation predictionhypothetical real time gnss modeling of the 2016 mw 7 8 kaikōura earthquake

gradual unlocking of plate boundary controlled initiation of the 2014 iquique earthquake a long foreshock series unlocked the south american plate boundary until eventually initiating the m 8 1 iquique chile earthquake two groups publishing in this issue of nature analyse the seismic context of the iquique earthquake that occurred off the coast of northern chile on 1 april 2014 in a seismic zone that had been quiescent since a significant event in 1877 gavin hayes et al identify areas of remaining or elevated earthquake hazard along the megathrust fault in the region and conclude that the 2014 iquique event was not the earthquake that had been anticipated given that significant sections of the northern chile subduction zone have not ruptured in almost 150 years they suggest that it is likely that future megathrust earthquakes will occur south and potentially north of the 2014 iquique sequence bernd schurr et al show that the april 2014 earthquake broke a central fraction of the northern chile seismic gap the last major segment of the south american plate boundary that had yet to rupture in the past century from july 2013 up to the april earthquake they identify three seismic clusters along this part of the plate boundary each lasting a few weeks with earthquakes of increasing peak magnitudes they conclude that these seismic clusters and their slip transients reflect a gradual weakening of the central part of the seismic gap that was instrumental in initiating the final failure on 1 april 2014 northern chile was struck by a magnitude 8 1 earthquake following a protracted series of foreshocks the integrated plate boundary observatory chile monitored the entire sequence of events providing unprecedented resolution of the build up to the main event and its rupture evolution here we show that the iquique earthquake broke a central fraction of the so called northern chile seismic gap the last major segment of the south american plate boundary that had not ruptured in the past century1 2 since july 2013 three seismic clusters each lasting a few weeks hit this part of the plate boundary with earthquakes of increasing peak magnitudes starting with the second cluster geodetic observations show surface displacements that can be associated with slip on the plate interface these seismic clusters and their slip transients occupied a part of the plate interface that was transitional between a fully locked and a creeping portion leading up to this earthquake the b value of the foreshocks gradually decreased during the years before the earthquake reversing its trend a few days before the iquique earthquake the mainshock finally nucleated at the northern end of the foreshock area which skirted a locked patch and ruptured mainly downdip towards higher locking peak slip was attained immediately downdip of the foreshock region and at the margin of the locked patch we conclude that gradual weakening of the central part of the seismic gap accentuated by the foreshock activity in a zone of intermediate seismic coupling was instrumental in causing final failure distinguishing the iquique earthquake from most great earthquakes finally only one third of the gap was broken and the remaining locked segments now pose a significant increased seismic hazard with the potential to host an earthquake with a magnitude of 8 5

mineralogical and chemical characterization of lunar highland soils insights into the space weathering of soils on airless bodies 1 with reflectance spectroscopy one is measuring only properties of the fine grained regolith most affected by space weathering the lunar soil characterization consortium has undertaken the task of coordinated characterization of lunar soils with respect to their mineralogical and chemical makeup it is these lunar soils that are being used as ground truth for all airless bodies modal abundances and chemistries of minerals and glasses in the finest size fractions 20 45 10 20 and 10 m of four apollo 14 and six apollo 16 highland soils have been determined as well as their bulk chemistry and is feo values bidirectional reflectance measurements 0 3 2 6 m of all samples were performed in the reflectance experiment laboratory a significant fraction of nanophase fe0 np fe0 appears to reside in agglutinitic glasses however as grain size of a soil decreases the percentage of total iron present as np fe0 increases significantly whereas the agglutinitic glass content rises only slightly this is evidence for a large contribution to the is feo values from the surface correlated nanophase fe0 particularly in the 10 m size fraction the compositions of the agglutinitic glasses in these fine fractions of the highland soils are different from the bulk chemistry of that size however compositional trends of the glasses are not the same as those observed for mare soils it is apparent that the glasses in the highland soils contain chemical components from outside their terrains it is proposed that the apollo 16 soils have been adulterated by the addition of impact transported soil components from surrounding maria

retrieving real time co seismic displacements using gps glonass a preliminary report from the september 2015 mw 8 3 illapel earthquake in chile

tsunami early warning using gps shield arrays 1 the 2004 catastrophic indian ocean tsunami has strongly emphasized the need for reliable tsunami early warning systems another giant tsunamigenic earthquake may occur west of sumatra close to the large city of padang we demonstrate that the presence of islands between the trench and the sumatran coast makes earthquake induced tsunamis especially sensitive to slip distribution on the rupture plane as wave heights at padang may differ by more than a factor of 5 for earthquakes having the same seismic moment magnitude and rupture zone geometry but different slip distribution hence reliable prediction of tsunami wave heights for padang cannot be provided using traditional earthquake magnitude based methods we show however that such a prediction can be issued within 10 minutes of an earthquake by incorporating special types of near field gps arrays gps shield these arrays measure both vertical and horizontal displacements and can resolve higher order features of the slip distribution on the fault than the seismic moment if placed above the rupture zone or are less than 100 km away of the rupture zone stations in the arrays are located as close as possible to the trench and are aligned perpendicular to the trench i e parallel to the expected gradient of surface coseismic displacement in the case of sumatra and java the gps shield arrays should be placed at mentawai islands located between the trench and sumatra and directly at the sumatra and java western coasts we demonstrate that the gps shield can also be applied to northern chile where giant earthquakes may also occur in the near future moreover this concept may be applied globally to many other tsunamigenic active margins where the land is located above or close to seismogenic zones

local tsunami warnings perspectives from recent large events we demonstrate a flexible strategy for local tsunami warning that relies on regional geodetic and seismic stations through retrospective analysis of four recent tsunamigenic events in japan and chile we show that rapid earthquake source information provided by methodologies developed for earthquake early warning can be used to generate timely estimates of maximum expected tsunami amplitude with enough accuracy for tsunami warning we validate the technique by comparing to detailed models of earthquake source and tsunami propagation as well as field surveys of tsunami inundation our approach does not require deployment of new geodetic and seismic instrumentation in many subduction zones and could be implemented rapidly by national monitoring and warning agencies we illustrate the potential impact of our method with a detailed comparison to the actual timeline of events during the recent 2015 mw8 3 illapel chile earthquake and tsunami that prompted the evacuation of 1 million people

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

a comparison of the energy balance and bulk aerodynamic approaches for estimating glacier melt description de 2 modeles d ablation de glacier sur la base d observations meteorologiques par utilisation d une approche aerodynamique et d un bilan energetique on teste les modeles avec les donnees sur le glacier ivory

real time centroid moment tensor determination for large earthquakes from local and regional displacement records summary we present an algorithm to rapidly determine the moment tensor and centroid location for large earthquakes employing local and regional real time high rate displacement records from gps the algorithm extracts the coseismic offset from the displacement waveforms and uses the information to invert for the moment tensor the green s functions for a layered earth are obtained numerically from open source code edgrn to determine the centroid multiple inversions are simultaneously performed within a grid of inversion nodes and the node with the smallest misfit is then assigned the centroid location we show results for two large earthquakes replayed in simulated real time mode using recorded 1 hz gps displacements the 2003 mw 8 3 tokachi oki and the 2010 mw 7 2 el mayor cucapah earthquakes we demonstrate that it is feasible to obtain accurate cmt solutions within the first 2 3 min after rupture initiation without any prior assumptions on fault characteristics demonstrating an order of magnitude improvement in latency compared to existing seismic methods for the two earthquakes studied this methodology is useful for rapid earthquake response tsunami prediction and as a starting point for rapid finite fault modelling

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

the nature and origin of rims on lunar soil grains abstract space weathering processes that operate in the lunar regolith modify the surfaces of lunar soil grains transmission electron microscope analysis of the lunar soil grains from the fine size fraction of several lunar soils show that most grains are surrounded by thin 60 200 nm thick rims the microstructure and chemical compositions of the rims can be used to classify rims into four broad categories amorphous inclusion rich multiple and vesicular amorphous rims are noncrystalline generally lack crystalline inclusions show evidence for preferential sputtering of cations and are produced largely by solar wind irradiation damage inclusion rich rims contain abundant nanometer sized grains of fe metal as randomly dispersed inclusions or as distinct layers embedded in an amorphous silica rich matrix inclusion rich rims are compositionally distinct from their host grains and typically contain accumulations of elements that are not indigenous to the host inclusion rich rims are formed largely by the deposition of impact generated vapors with a contribution from the deposition of sputtered ions a continuum in the chemical and microstructural properties exists between typical amorphous rims and typical inclusion rich rims multiple rims consist of a distinct radiation damaged layer up to 50 nm thick that is overlain by vapor deposited material of comparable thickness vesicular rims are compositionally similar to their hosts and are characterized by an abundance of small the formation of rims on lunar soils is complex and involves several processes whose effects may be superimposed from this study it is shown that one process does not dominate and that the relative importance of vapor deposition is comparable to radiation damage in the formation of rims on lunar silicate grains the presence of rims on lunar soil grains particularly those with nanometer sized fe metal inclusions may have a major influence on the optical and magnetic properties of lunar soils

enhanced gps inversion technique applied to the 2004 sumatra earthquake and tsunami 1 since the devastating earthquake and tsunami in 2004 offshore sumatra many source models have been put forward recent studies clearly show that modern gps processing could achieve high resolving power for slip in near real time which is crucial for determining tsunami initial conditions provided accurate gps processing and inversion here we propose an inversion technique with improved representation of the subduction zone geometry and physically justified boundary conditions we show that the discrepancy between the inversion of near and far field gps data for the 2004 event which is often explained by postseismic slip can be eliminated by using our inversion method and iasp91 earth model inverted source models including versions with splay faulting are shown to be consistent with satellite altimetry data of offshore tsunami wave height suggesting that displacement at the splay fault might have been present but was likely a second order process

centroid moment tensor inversions using high rate gps waveforms displacement time series recorded by global positioning system gps receivers are a new type of near field waveformobservation of the seismic source we have developed an inversion method which enables the recovery of an earthquake s mechanism and centroid coordinates from such data our approach is identical to that of the classical centroid moment tensor cmt algorithm except that we forward model the seismic wavefield using a method that is amenable to the efficient computation of synthetic gps seismograms and their partial derivatives we demonstrate the validity of our approach by calculating cmt solutions using 1 hz gps data for two recent earthquakes in japan these results are in good agreement with independently determined source models of these events with wider availability of data we envisage the cmt algorithm providing a tool for the systematic inversion of gps waveforms as is already the case for teleseismic data furthermore this general inversion method could equally be applied to other near field earthquake observations such as those made using accelerometers

application of real time gps to earthquake early warning 1 we explore the use of real time high rate gps displacement data for earthquake early warning using 1 hz displacement waveforms from the april 4 2010 mw 7 2 el mayor cucapah earthquake we compare these data to those provided by the broadband velocity and accelerometer instrumentation of the southern california seismic network the unique information provided by the gps based displacement timeseries is the permanent static displacement using a simple algorithm that can be applied in real time we extract the static offset shortly after the s wave arrival around the time of the observed peak shaking at the same site and before shaking at more distant locations these data can be used as they become available to provide a robust estimate of the earthquake magnitude which ranges from 6 8 to 7 0 in this case we therefore conclude that real time high rate gps can provide a useful and independent assessment of earthquake magnitude for the purpose of earthquake early warning and real time earthquake information systems in general including tsunami warning systems

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

real time inversion of gps data for finite fault modeling and rapid hazard assessment 1 responses to recent great earthquakes and ensuing tsunamis in sumatra chile and japan with the resulting loss of life and damage to infrastructure demonstrate that our ability to ascertain the full extent of slip of catastrophic earthquakes and their tsunamigenic potential in the first minutes after the initiation of rupture is problematic regional gps networks such as those in western north america and japan are complementary to seismic networks by being able to directly measure displacements close to the source during large earthquakes in real time we report on rapid modeling of two large earthquakes the 2003 mw 8 3 tokachi oki earthquake 100 km offshore hokkaido island using 356 geonet stations and the 2010 mw 7 2 el mayor cucapah earthquake in northern baja california using 95 crtn stations in southern california about 75 km northwest of the epicenter working in a simulated real time mode we invert for finite fault slip in a homogeneous elastic half space using green s functions obtained from okada s formulation we compare two approaches the first starts with a catalog of pre defined faults while the second uses a rapid centroid moment tensor solution to provide an initial estimate of the ruptured fault plane in either case we are able to characterize both earthquakes in less than two minutes reducing the time necessary to obtain finite fault slip and moment magnitude for medium and greater earthquakes compared to traditional methods by an order of magnitude

rapid modeling of the 2011 mw 9 0 tohoku oki earthquake with seismogeodesy 1 rapid characterization of finite fault geometry and slip for large earthquakes is important for mitigation of seismic and tsunamigenic hazards saturation of near source weak motion and problematic integration of strong motion data into displacements make this difficult in real time combining gps and accelerometer data to estimate seismogeodetic displacement waveforms overcomes these limitations by providing mm level three dimensional accuracy and improved estimation of coseismic deformation compared to gps only methods we leverage collocated gps and accelerometer data from the 2011 mw 9 0 tohoku oki japan earthquake by replaying them in simulated real time mode using a novel approach to account for fault finiteness we generate an accurate centroid moment tensor solution independently of any constraint on the slab geometry followed by a finite fault slip model the replay of gps and seismic data demonstrates that robust models could have been made available within 3 min of earthquake initiation

detecting tsunami genesis and scales directly from coastal gps stations 1 different from the conventional approach to tsunami warnings that rely on earthquake magnitude estimates we have found that coastal gps stations are able to detect continental slope displacements of faulting due to big earthquakes and that the detected seafloor displacements are able to determine tsunami source energy and scales instantaneously this method has successfully replicated three historical tsunamis caused by the 2004 sumatra earthquake the 2005 nias earthquake and the 1964 alaska earthquake respectively and has been compared favorably with the conventional seismic solutions that usually take hours or days to get through inverting seismographs because many coastal gps stations are already in operation for measuring ground motions in real time as often as once every few seconds this study suggests a practical way of identifying tsunamigenic earthquakes for early warnings and reducing false alarms

high rate coseismic displacements from tightly integrated processing of raw gps and accelerometer data high rate gps and seismic sensors are mutually contributing to seismological applications for capturing earthquake induced coseismic displacements in this study we propose an approach for tightly integrating gps and strong motion data on raw observation level to increase the quality of the derived displacements the performance of the proposed approach is demonstrated using 5 hz high rate gps and 200 hz strong motion data collected during the el mayor cucapah earthquake m w 7 2 2010 april 4 in baja california mexico the new approach not only takes advantages of both gps and strong motion sensors but also improves the reliability of the displacement by enhancing gps integer cycle phase ambiguity resolution which is very critical for deriving displacements with highest quality

earthquake source parameters from gps measured static displacements with potential for real time application 1 we describe a method for determining an optimal centroid moment tensor solution of an earthquake from a set of static displacements measured using a network of global positioning system receivers using static displacements observed after the 4 april 2010 mw 7 2 el mayor cucapah mexico earthquake we perform an iterative inversion to obtain the source mechanism and location which minimize the least squares difference between data and synthetics the efficiency of our algorithm for forward modeling static displacements in a layered elastic medium allows the inversion to be performed in real time on a single processor without the need for precomputed libraries of excitation kernels we present simulated real time results for the el mayorcucapah earthquake the only a priori information that our inversion scheme needs is a crustal model and approximate source location so the method proposed here may represent an improvement on existing early warning approaches that rely on foreknowledge of fault locations and geometries citation o toole t b a p valentine and j h woodhouse 2013 earthquake source parameters from gpsmeasured static displacements with potential for real time application geophys res lett 40 6 0 65 doi 10 1029 2012gl054209

estimate of glacier ablation under a debris layer from surface temperature and meteorological variables a simple model suggests that th e a bl ati on under a debris la yer could be estimated from meteorological variables if th e surface temperat ure data of the layer are available this method was tested by a nal yz in g the data o btained from ex periments with artificial d ebris layers fairly good agreement was o bta ined between th e estimated and the experimenta l data r esume evaluq ion de ab lalion d un glacier sous une couche di lritique a par ir de la temperature de sw ace et de variables meteorologiques ii est possible grace a un modele simple d evalu er i abl ation d un glacier sous un e co uche de roches detritiques en fonction de variables meteorologiques si i on possede des do nnees sur la temperatu re de surface de la couche detritique ce modi le a ete veri fie lors de i analyse des donnees pro vena nt d essais effect ue s a u moyen de couches detritiques artifi cielles les donnees ex perimentales so nt ve nues corroborer les donnees obtenues a i aid e des modele s theoriques z usammenfassung abschiitzung der eisablation unter einer schullschicht mit hilfe der obelj iichentemperatur ulld lion meteorologischell oaten aus einem einfachen modell geht hervo r dass die ablation unter ei ner schuttschicht a us meteorologischen oaten abgeschatzt we rden kann wenn die oberflachentemperatur der schicht bekannt ist oi ese methode wurde mit hilfe von oaten erprobt die a us versuchen mit klinstlichen schuttschichten hervo rgi nge n zwischen den abgeschii tzten und den experimentell gewonn enen werten ergab sich ei ne recht gute uberei nstimmung

real time high rate co seismic displacement from ambiguity fixed precise point positioning application to earthquake early warning 1 nowadays more and more high rate real time gps data become available that provide a great opportunity to contribute to earthquake early warning eew system in terms of capturing regional surface displacements as an independent information source useful for promptly estimating the magnitude of large destructive earthquake in our study we demonstrate the performance of the real time ambiguity fixed precise point positioning ppp approach using 5 hz gps data collected during el mayor cucapah earthquake mw 7 2 4 april 2010 the ppp based displacements show to agree with accelerometer based displacement at centimeter level the key for successfully obtaining high precision displacements is the efficient ambiguity resolution ppp with ambiguity fixing can result in correct permanent co seismic offsets and correct recovery of moment magnitude and fault slip inversion at levels comparable to post processing

rapid determination of earthquake magnitude using gps for tsunami warning systems 1 the 26 december 2004 sumatra earthquake mw 9 2 9 3 generated the most deadly tsunami in history yet within the first hour the true danger of a major oceanwide tsunami was not indicated by seismic magnitude estimates which were far too low mw 8 0 8 5 this problem relates to the inherent saturation of early seismic wave methods here we show that the earthquake s true size and tsunami potential can be determined using global positioning system gps data up to only 15 min after earthquake initiation by tracking the mean displacement of the earth s surface associated with the arrival of seismic waves within minutes displacements of 10 mm are detectable as far away as india consistent with results using weeks of data after the event these displacements imply mw 9 0 0 1 indicating a high tsunami potential this suggests existing gps infrastructure could be developed into an effective component of tsunami warning systems

temporal point positioning approach for real time gnss seismology using a single receiver 1 high rate global navigation satellite systems gnss has an increasing number of applications in geohazard monitoring gnss derived displacements can provide important information for magnitude estimation and fault slip inversion which is critical for seismic and tsunamigenic hazard mitigation in this paper we propose a new approach to quickly capture coseismic displacements with a single gnss receiver in real time the new approach can overcome the convergence problem of precise point positioning and also avoids the integration process of the variometric approach using the results of the 2011 tohoku oki earthquake it is demonstrated that the proposed method can provide accurate displacement waveforms and permanent coseismic offsets at an accuracy of few centimeters and can also reliably recover the moment magnitude and fault slip distribution