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Sample records for 3d s-wave velocity

  1. 3D P and S Wave Velocity Structure and Tremor Locations in the Parkfield Region

    NASA Astrophysics Data System (ADS)

    Zeng, X.; Thurber, C. H.; Shelly, D. R.; Bennington, N. L.; Cochran, E. S.; Harrington, R. M.

    2014-12-01

    We have assembled a new dataset to refine the 3D seismic velocity model in the Parkfield region. The S arrivals from 184 earthquakes recorded by the Parkfield Experiment to Record MIcroseismicity and Tremor array (PERMIT) during 2010-2011 were picked by a new S wave picker, which is based on machine learning. 74 blasts have been assigned to four quarries, whose locations were identified with Google Earth. About 1000 P and S wave arrivals from these blasts at permanent seismic network were also incorporated. Low frequency earthquakes (LFEs) occurring within non-volcanic tremor (NVT) are valuable for improving the precision of NVT location and the seismic velocity model at greater depths. Based on previous work (Shelley and Hardebeck, 2010), waveforms of hundreds of LFEs in same family were stacked to improve signal qualify. In a previous study (McClement et al., 2013), stacked traces of more than 30 LFE families at the Parkfileld Array Seismic Observatory (PASO) have been picked. We expanded our work to include LFEs recorded by the PERMIT array. The time-frequency Phase Weight Stacking (tf-PWS) method was introduced to improve the stack quality, as direct stacking does not produce clear S-wave arrivals on the PERMIT stations. This technique uses the coherence of the instantaneous phase among the stacked signals to enhance the signal-to-noise ratio (SNR) of the stack. We found that it is extremely effective for picking LFE arrivals (Thurber et al., 2014). More than 500 P and about 1000 S arrivals from 58 LFE families were picked at the PERMIT and PASO arrays. Since the depths of LFEs are much deeper than earthquakes, we are able to extend model resolution to lower crustal depths. Both P and S wave velocity structure have been obtained with the tomoDD method. The result suggests that there is a low velocity zone (LVZ) in the lower crust and the location of the LVZ is consistent with the high conductivity zone beneath the southern segment of the Rinconada fault that

  2. Low velocity crustal flow and crust-mantle coupling mechanism in Yunnan, SE Tibet, revealed by 3D S-wave velocity and azimuthal anisotropy

    NASA Astrophysics Data System (ADS)

    Chen, Haopeng; Zhu, Liangbao; Su, Youjin

    2016-08-01

    We used teleseismic data recorded by a permanent seismic network in Yunnan, SE Tibet, and measured the interstation Rayleigh wave phase velocity between 10 and 60 s. A two-step inversion scheme was used to invert for the 3D S-wave velocity and azimuthal anisotropy structure of 10-110 km. The results show that there are two low velocity channels between depths of 20-30 km in Yunnan and that the fast axes are sub-parallel to the strikes of the low velocity channels, which supports the crustal flow model. The azimuthal anisotropy pattern is quite complicated and reveals a complex crust-mantle coupling mechanism in Yunnan. The N-S trending Lüzhijiang Fault separates the Dianzhong Block into two parts. In the western Dianzhong Block, the fast axis of the S-wave changes with depth, which indicates that the crust and the lithospheric mantle are decoupled. In the eastern Dianzhong Block and the western Yangtze Craton, the crust and the lithospheric mantle may be decoupled because of crustal flow, despite a coherent S-wave fast axis at depths of 10-110 km. In addition, the difference between the S-wave fast axis in the lithosphere and the SKS splitting measurement suggests that the lithosphere and the upper mantle are decoupled there. In the Baoshan Block, the stratified anisotropic pattern suggests that the crust and the upper mantle are decoupled.

  3. 3-D P- and S-wave velocity structure and low-frequency earthquake locations in the Parkfield, California region

    NASA Astrophysics Data System (ADS)

    Zeng, Xiangfang; Thurber, Clifford H.; Shelly, David R.; Harrington, Rebecca M.; Cochran, Elizabeth S.; Bennington, Ninfa L.; Peterson, Dana; Guo, Bin; McClement, Kara

    2016-09-01

    To refine the 3-D seismic velocity model in the greater Parkfield, California region, a new data set including regular earthquakes, shots, quarry blasts and low-frequency earthquakes (LFEs) was assembled. Hundreds of traces of each LFE family at two temporary arrays were stacked with time-frequency domain phase weighted stacking method to improve signal-to-noise ratio. We extend our model resolution to lower crustal depth with LFE data. Our result images not only previously identified features but also low velocity zones (LVZs) in the area around the LFEs and the lower crust beneath the southern Rinconada Fault. The former LVZ is consistent with high fluid pressure that can account for several aspects of LFE behaviour. The latter LVZ is consistent with a high conductivity zone in magnetotelluric studies. A new Vs model was developed with S picks that were obtained with a new autopicker. At shallow depth, the low Vs areas underlie the strongest shaking areas in the 2004 Parkfield earthquake. We relocate LFE families and analyse the location uncertainties with the NonLinLoc and tomoDD codes. The two methods yield similar results.

  4. 3-D P- and S-wave velocity structure and low-frequency earthquake locations in the Parkfield, California region

    USGS Publications Warehouse

    Zeng, Xiangfang; Thurber, Clifford H.; Shelly, David R.; Harrington, Rebecca M.; Cochran, Elizabeth S.; Bennington, Ninfa L.; Peterson, Dana; Guo, Bin; McClement, Kara

    2016-01-01

    To refine the 3-D seismic velocity model in the greater Parkfield, California region, a new data set including regular earthquakes, shots, quarry blasts and low-frequency earthquakes (LFEs) was assembled. Hundreds of traces of each LFE family at two temporary arrays were stacked with time–frequency domain phase weighted stacking method to improve signal-to-noise ratio. We extend our model resolution to lower crustal depth with LFE data. Our result images not only previously identified features but also low velocity zones (LVZs) in the area around the LFEs and the lower crust beneath the southern Rinconada Fault. The former LVZ is consistent with high fluid pressure that can account for several aspects of LFE behaviour. The latter LVZ is consistent with a high conductivity zone in magnetotelluric studies. A new Vs model was developed with S picks that were obtained with a new autopicker. At shallow depth, the low Vs areas underlie the strongest shaking areas in the 2004 Parkfield earthquake. We relocate LFE families and analyse the location uncertainties with the NonLinLoc and tomoDD codes. The two methods yield similar results.

  5. 3D velocity distribution of P- and S-waves in a biotite gneiss, measured in oil as the pressure medium: Comparison with velocity measurements in a multi-anvil pressure apparatus and with texture-based calculated data

    NASA Astrophysics Data System (ADS)

    Lokajíček, T.; Kern, H.; Svitek, T.; Ivankina, T.

    2014-06-01

    Ultrasonic measurements of the 3D velocity distribution of P- and S-waves were performed on a spherical sample of a biotite gneiss from the Outokumpu scientific drill hole. Measurements were done at room temperature and pressures up to 400 and 70 MPa, respectively, in a pressure vessel with oil as a pressure medium. A modified transducer/sample assembly and the installation of a new mechanical system allowed simultaneous measurements of P- and S-wave velocities in 132 independent directions of the sphere on a net in steps of 15°. Proper signals for P- and S-waves could be recorded by coating the sample surface with a high-viscosity shear wave gel and by temporal point contacting of the transmitter and receiver transducers with the sample surface during the measurements. The 3D seismic measurements revealed a strong foliation-related directional dependence (anisotropy) of P- and S-wave velocities, which is confirmed by measurements in a multi-anvil apparatus on a cube-shaped specimen of the same rock. Both experimental approaches show a marked pressure sensitivity of P- and S-wave velocities and velocity anisotropies. With increasing pressure, P- and S-wave velocities increase non-linearly due to progressive closure of micro-cracks. The reverse is true for velocity anisotropy. 3D velocity calculations based on neutron diffraction measurements of crystallographic preferred orientation (CPO) of major minerals show that the intrinsic bulk anisotropy is basically caused by the CPO of biotite constituting about 23 vol.% of the rock. Including the shape of biotite grains and oriented low-aspect ratio microcracks into the modelling increases bulk anisotropy. An important finding from this study is that the measurements on the sample sphere and on the sample cube displayed distinct differences, particularly in shear wave velocities. It is assumed that the differences are due to the different geometries of the samples and the configuration of the transducer-sample assembly

  6. Title of abstract - Different approaches to the determining of 3-d P and S wave velocity structures of the crust beneath Northern Tien Shan

    NASA Astrophysics Data System (ADS)

    Kryukova, O.

    2003-04-01

    The seismic images of the crust beneath Northern Tien Shan (NTS) are obtained with using of different sets of data and several algorithms for solution of local earthquake tomography problem. The NTS is a very interesting region from geophysical point if view due to high seismic activity caused by interplate collision: Tien Shan and Kazakh. A rectangular region under investigation is constrained by lines 41.90o N - 43.40o N and 73.50o E- 76.50o E. 14661 P and 14436 S wave arrival times recorded 12 seismic stations of the Kyrgyzstan Broadband Network (KNET) from local earthquake in 1991-1999 years are used. In addition, data from 267 local earthquake recorded over a period of about 20 years by a regional arrays of 93 seismographs in NTS are involved in inversions. 1-d optimal velocity models and stations delays are estimated with help of program VELEST (E.Kissling, 1995). Block parameterization of model and ray tracing described by Thurber and Ellsworth (1980) are used for determination of 3-d velocity structure and relocation of events as one of the approaches (programs S.Roecker Sphypit90 and Sphrel3d). Other approach consists in application linear or cubic B spline interpolation of velocity function and ray tracing Um and Thurber (1987) for the solution of forward problem (program C.Thurber et al. Simulps and own program). The data resolution analysis and statistical analysis of models was carried out. Calculated P wave tomographic models were compared with tomographic models S.Roecker et al. (1993), S.Ghose et al. (1998) and T.Sabitova (1996). The main result is the confirmation of existence of different seismic velocity structure beneath Kyrgyz Range and Chu Basin. Using various sets of date and methods for reconstruction velocity model is effective in reveal of more reliable velocity heterogeneities in the domain of research. The author is grateful to dr. I. Kitov for help and to dr. I.Sanina for useful discussion.

  7. Detailed 3-D S-wave velocity beneath the High Lava Plains, Oregon, from 2-plane-wave Rayleigh wave inversions

    NASA Astrophysics Data System (ADS)

    Wagner, L. S.; Forsyth, D. W.; Fouch, M. J.; James, D. E.

    2009-12-01

    The High Lava Plains (HLP) of eastern Oregon represent an unusual track of bimodal volcanism extending from the southeastern-most corner of the state to its current position beneath the Newberry Volcano on the eastern margin of the Cascades. The silicic volcanism is time progressive along this track, beginning some 15 Ma near the Owyhee plateau and then trending to the north east. The timing and location of the start of the HLP coincides with that of the initial volcanism associated with the Yellowstone/Snake River Plain track (YSRP). While the YSRP has often been interpreted as the classic intra-continental hot spot track, the HLP, which trends almost normal to absolute plate motion, is harder to explain. This study uses the 100+ stations associated with the HLP seismic deployment together with another ~100 Earthscope Transportable Array stations (TA) to perform a high resolution inversion for Rayleigh wave phase velocities using the 2-plane-wave methodology of Forsyth and Li (2004). Because of the comparatively small grid spacing of this study, we are able to discern much finer scale structures than studies looking at the entire western U.S. with only TA stations. Preliminary results indicate very low velocities across the study area, especially at upper mantle depths. Especially low velocities are seen beneath the Owyhee plateau and along both the HLP and YSRP tracks. Final details about the exact geometries of these features will help constrain possible scenarios for the formation of the HLP volcanic sequence.

  8. A simple method of predicting S-wave velocity

    USGS Publications Warehouse

    Lee, M.W.

    2006-01-01

    Prediction of shear-wave velocity plays an important role in seismic modeling, amplitude analysis with offset, and other exploration applications. This paper presents a method for predicting S-wave velocity from the P-wave velocity on the basis of the moduli of dry rock. Elastic velocities of water-saturated sediments at low frequencies can be predicted from the moduli of dry rock by using Gassmann's equation; hence, if the moduli of dry rock can be estimated from P-wave velocities, then S-wave velocities easily can be predicted from the moduli. Dry rock bulk modulus can be related to the shear modulus through a compaction constant. The numerical results indicate that the predicted S-wave velocities for consolidated and unconsolidated sediments agree well with measured velocities if differential pressure is greater than approximately 5 MPa. An advantage of this method is that there are no adjustable parameters to be chosen, such as the pore-aspect ratios required in some other methods. The predicted S-wave velocity depends only on the measured P-wave velocity and porosity. ?? 2006 Society of Exploration Geophysicists.

  9. Anomalously low amplitude of S waves produced by the 3D structures in the lower mantle

    NASA Astrophysics Data System (ADS)

    To, Akiko; Capdeville, Yann; Romanowicz, Barbara

    2016-07-01

    Direct S and Sdiff phases with anomalously low amplitudes are recorded for the earthquakes in Papua New Guinea by seismographs in northern America. According to the prediction by a standard 1D model, the amplitudes are the lowest at stations in southern California, at a distance and azimuth of around 95° and 55°, respectively, from the earthquake. The amplitude anomaly is more prominent at frequencies higher than 0.03 Hz. We checked and ruled out the possibility of the anomalies appearing because of the errors in the focal mechanism used in the reference synthetic waveform calculations. The observed anomaly distribution changes drastically with a relatively small shift in the location of the earthquake. The observations indicate that the amplitude reduction is likely due to the 3D shear velocity (Vs) structure, which deflects the wave energy away from the original ray paths. Moreover, some previous studies suggested that some of the S and Sdiff phases in our dataset are followed by a prominent postcursor and show a large travel time delay, which was explained by placing a large ultra-low velocity zone (ULVZ) located on the core-mantle boundary southwest of Hawaii. In this study, we evaluated the extent of amplitude anomalies that can be explained by the lower mantle structures in the existing models, including the previously proposed ULVZ. In addition, we modified and tested some models and searched for the possible causes of low amplitudes. Full 3D synthetic waveforms were calculated and compared with the observations. Our results show that while the existing models explain the trends of the observed amplitude anomalies, the size of such anomalies remain under-predicted especially at large distances. Adding a low velocity zone, which is spatially larger and has less Vs reduction than ULVZ, on the southwest side of ULVZ, contributes to explain the low amplitudes observed at distances larger than 100° from the earthquake. The newly proposed low velocity zone

  10. Azimuthally Anisotropic 3D Velocity Continuation

    DOE PAGES

    Burnett, William; Fomel, Sergey

    2011-01-01

    We extend time-domain velocity continuation to the zero-offset 3D azimuthally anisotropic case. Velocity continuation describes how a seismic image changes given a change in migration velocity. This description turns out to be of a wave propagation process, in which images change along a velocity axis. In the anisotropic case, the velocity model is multiparameter. Therefore, anisotropic image propagation is multidimensional. We use a three-parameter slowness model, which is related to azimuthal variations in velocity, as well as their principal directions. This information is useful for fracture and reservoir characterization from seismic data. We provide synthetic diffraction imaging examples to illustratemore » the concept and potential applications of azimuthal velocity continuation and to analyze the impulse response of the 3D velocity continuation operator.« less

  11. High-resolution 3-D S-wave Tomography of upper crust structures in Yilan Plain from Ambient Seismic Noise

    NASA Astrophysics Data System (ADS)

    Chen, Kai-Xun; Chen, Po-Fei; Liang, Wen-Tzong; Chen, Li-Wei; Gung, YuanCheng

    2015-04-01

    The Yilan Plain (YP) in NE Taiwan locates on the western YP of the Okinawa Trough and displays high geothermal gradients with abundant hot springs, likely resulting from magmatism associated with the back-arc spreading as attested by the offshore volcanic island (Kueishantao). YP features NS distinctive characteristics that the South YP exhibits thin top sedimentary layer, high on-land seismicity and significant SE movements, relative those of the northern counterpart. A dense network (~2.5 km station interval) of 89 Texan instruments was deployed in Aug. 2014, covering most of the YP and its vicinity. The ray path coverage density of each 0.015 degree cells are greater than 150 km that could provide the robustness assessment of tomographic results. We analyze ambient noise signals to invert a high-resolution 3D S-wave model for shallow velocity structures in and around YP. The aim is to investigate the velocity anomalies corresponding to geothermal resources and the NS geological distinctions aforementioned. We apply the Welch's method to generate empirical Rayleigh wave Green's functions between two stations records of continuous vertical components. The group velocities of thus derived functions are then obtained by the multiple-filter analysis technique measured at the frequency range between 0.25 and 1 Hz. Finally, we implement a wavelet-based multi-scale parameterization technique to construct 3D model of S-wave velocity. Our first month results exhibit low velocity in the plain, corresponding existing sediments, those of whole YP show low velocity offshore YP and those of high-resolution south YP reveal stark velocity contrast across the Sanshin fault. Key words: ambient seismic noises, Welch's method, S-wave, Yilan Plain

  12. Predicting S-wave velocities for unconsolidated sediments at low effective pressure

    USGS Publications Warehouse

    Lee, Myung W.

    2010-01-01

    Accurate S-wave velocities for shallow sediments are important in performing a reliable elastic inversion for gas hydrate-bearing sediments and in evaluating velocity models for predicting S-wave velocities, but few S-wave velocities are measured at low effective pressure. Predicting S-wave velocities by using conventional methods based on the Biot-Gassmann theory appears to be inaccurate for laboratory-measured velocities at effective pressures less than about 4-5 megapascals (MPa). Measured laboratory and well log velocities show two distinct trends for S-wave velocities with respect to P-wave velocity: one for the S-wave velocity less than about 0.6 kilometer per second (km/s) which approximately corresponds to effective pressure of about 4-5 MPa, and the other for S-wave velocities greater than 0.6 km/s. To accurately predict S-wave velocities at low effective pressure less than about 4-5 MPa, a pressure-dependent parameter that relates the consolidation parameter to shear modulus of the sediments at low effective pressure is proposed. The proposed method in predicting S-wave velocity at low effective pressure worked well for velocities of water-saturated sands measured in the laboratory. However, this method underestimates the well-log S-wave velocities measured in the Gulf of Mexico, whereas the conventional method performs well for the well log velocities. The P-wave velocity dispersion due to fluid in the pore spaces, which is more pronounced at high frequency with low effective pressures less than about 4 MPa, is probably a cause for this discrepancy.

  13. 3-D seismic velocity and attenuation structures in the geothermal field

    SciTech Connect

    Nugraha, Andri Dian; Syahputra, Ahmad; Fatkhan,; Sule, Rachmat

    2013-09-09

    We conducted delay time tomography to determine 3-D seismic velocity structures (Vp, Vs, and Vp/Vs ratio) using micro-seismic events in the geothermal field. The P-and S-wave arrival times of these micro-seismic events have been used as input for the tomographic inversion. Our preliminary seismic velocity results show that the subsurface condition of geothermal field can be fairly delineated the characteristic of reservoir. We then extended our understanding of the subsurface physical properties through determining of attenuation structures (Qp, Qs, and Qs/Qp ratio) using micro-seismic waveform. We combined seismic velocities and attenuation structures to get much better interpretation of the reservoir characteristic. Our preliminary attanuation structures results show reservoir characterization can be more clearly by using the 3-D attenuation model of Qp, Qs, and Qs/Qp ratio combined with 3-D seismic velocity model of Vp, Vs, and Vp/Vs ratio.

  14. Constraining depth range of S wave velocity decrease after large earthquakes near Parkfield, California

    NASA Astrophysics Data System (ADS)

    Wu, Chunquan; Delorey, Andrew; Brenguier, Florent; Hadziioannou, Celine; Daub, Eric G.; Johnson, Paul

    2016-06-01

    We use noise correlation and surface wave inversion to measure the S wave velocity changes at different depths near Parkfield, California, after the 2003 San Simeon and 2004 Parkfield earthquakes. We process continuous seismic recordings from 13 stations to obtain the noise cross-correlation functions and measure the Rayleigh wave phase velocity changes over six frequency bands. We then invert the Rayleigh wave phase velocity changes using a series of sensitivity kernels to obtain the S wave velocity changes at different depths. Our results indicate that the S wave velocity decreases caused by the San Simeon earthquake are relatively small (~0.02%) and access depths of at least 2.3 km. The S wave velocity decreases caused by the Parkfield earthquake are larger (~0.2%), and access depths of at least 1.2 km. Our observations can be best explained by material damage and healing resulting mainly from the dynamic stress perturbations of the two large earthquakes.

  15. Three-dimensional P and S wave velocity structure of Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Benz, H.M.; Chouet, B.A.; Dawson, P.B.; Lahr, J.C.; Page, R.A.; Hole, J.A.

    1996-01-01

    The three-dimensional P and S wave structure of Redoubt Volcano, Alaska, and the underlying crust to depths of 7-8 km is determined from 6219 P wave and 4008 S wave first-arrival times recorded by a 30-station seismograph network deployed on and around the volcano. First-arrival times are calculated using a finite-difference technique, which allows for flexible parameterization of the slowness model and easy inclusion of topography and source-receiver geometry. The three-dimensional P wave velocity structure and hypocenters are determined simultaneously, while the three-dimensional S wave velocity model is determined using the relocated seismicity and an initial S wave velocity model derived from the P wave velocity model assuming an average Vp/Vs ratio of 1.78. Convergence is steady with approximately 73% and 52% reduction in P and S wave arrival time RMS, respectively, after 10 iterations. The most prominent feature observed in the three-dimensional velocity models derived for both P and S waves is a relative low-velocity, near-vertical, pipelike structure approximately 1 km in diameter that extends from 1 to 6 km beneath sea level. This feature aligns axially with the bulk of seismicity and is interpreted as a highly fractured and altered zone encompassing a magma conduit. The velocity structure beneath the north flank of the volcano between depths of 1 and 6 km is characterized by large lateral velocity variations. High velocities within this region are interpreted as remnant dikes and sills and low velocities as regions along which magma migrates. No large low-velocity body suggestive of a magma chamber is resolved in the the upper 7-8 km of the crust.

  16. Strong lateral variations of S-wave velocity in the upper mantle across the western Alps

    NASA Astrophysics Data System (ADS)

    Lyu, Chao; Pedersen, Helle; Paul, Anne; Zhao, Liang

    2016-04-01

    Absolute S-wave velocity gives more insight into temperature and mineralogy than relative P-wave velocity variations (ΔV p/ V p) imaged by teleseismic traveltime tomography. Moreover, teleseismic P-wave tomography has poor vertical but good horizontal resolution. By contrast, the inversion of surface waves dispersion data gives absolute S-wave velocity with a good vertical but relatively poor horizontal resolution. However, the horizontal resolution of surface wave imaging can be improved by using closely spaced stations in mini-arrays. In this work, we use Rayleigh wave phase velocity dispersion data to measure absolute S-wave velocities beneath the CIFALPS profile across the French-Italian western Alps. We apply the array processing technique proposed by Pedersen et al. (2003) to derive Rayleigh wave phase dispersion curves between 20 s and 100 s period in 15 mini-arrays along the CIFALPS line. We estimate a 1-D S-wave velocity model at depth 50-150 km beneath each mini-array by inverting the dispersion curves jointly with receiver functions. The joint inversion helps separating the crustal and mantle contributions in the inversion of dispersion curves. Distinct lithospheric structures and marked lateral variations are revealed beneath the study region, correlating well with regional geological and tectonic features. The average S-wave velocity from 50 to 150 km depth beneath the CIFALPS area is ˜4.48km/s, almost the same as in model AK135, indicating a normal upper mantle structure in average. Lateral variations are dominated by relatively low velocities (˜4.4km/s) in the mantle of the European plate, very low velocities (4.0km/s, i.e. approximately 12% lower than AK135) beneath the Dora Maira internal crystalline massif and high velocities (˜ 5.0km/s, i.e. 12% higher than AK135) beneath the Po plain. The lateral variations of S-wave velocity perturbation show the same features as the P wave tomography (Zhao et al., submitted), but with different amplitudes

  17. 2.5D S-wave velocity model of the TESZ area in northern Poland from receiver function analysis

    NASA Astrophysics Data System (ADS)

    Wilde-Piorko, Monika; Polkowski, Marcin; Grad, Marek

    2016-04-01

    Receiver function (RF) locally provides the signature of sharp seismic discontinuities and information about the shear wave (S-wave) velocity distribution beneath the seismic station. The data recorded by "13 BB Star" broadband seismic stations (Grad et al., 2015) and by few PASSEQ broadband seismic stations (Wilde-Piórko et al., 2008) are analysed to investigate the crustal and upper mantle structure in the Trans-European Suture Zone (TESZ) in northern Poland. The TESZ is one of the most prominent suture zones in Europe separating the young Palaeozoic platform from the much older Precambrian East European craton. Compilation of over thirty deep seismic refraction and wide angle reflection profiles, vertical seismic profiling in over one hundred thousand boreholes and magnetic, gravity, magnetotelluric and thermal methods allowed for creation a high-resolution 3D P-wave velocity model down to 60 km depth in the area of Poland (Grad et al. 2016). On the other hand the receiver function methods give an opportunity for creation the S-wave velocity model. Modified ray-tracing method (Langston, 1977) are used to calculate the response of the structure with dipping interfaces to the incoming plane wave with fixed slowness and back-azimuth. 3D P-wave velocity model are interpolated to 2.5D P-wave velocity model beneath each seismic station and synthetic back-azimuthal sections of receiver function are calculated for different Vp/Vs ratio. Densities are calculated with combined formulas of Berteussen (1977) and Gardner et al. (1974). Next, the synthetic back-azimuthal sections of RF are compared with observed back-azimuthal sections of RF for "13 BB Star" and PASSEQ seismic stations to find the best 2.5D S-wave models down to 60 km depth. National Science Centre Poland provided financial support for this work by NCN grant DEC-2011/02/A/ST10/00284.

  18. Investigation of surface wave amplitudes in 3-D velocity and 3-D Q models

    NASA Astrophysics Data System (ADS)

    Ruan, Y.; Zhou, Y.

    2010-12-01

    It has been long recognized that seismic amplitudes depend on both wave speed structures and anelasticity (Q) structures. However, the effects of lateral heterogeneities in wave speed and Q structures on seismic amplitudes has not been well understood. We investigate the effects of 3-D wave speed and 3-D anelasticity (Q) structures on surface-wave amplitudes based upon wave propagation simulations of twelve globally-distributed earthquakes and 801 stations in Earth models with and without lateral heterogeneities in wave speed and anelasticity using a Spectral Element Method (SEM). Our tomographic-like 3-D Q models are converted from a velocity model S20RTS using a set of reasonable mineralogical parameters, assuming lateral perturbations in both velocity and Q are due to temperature perturbations. Surface-wave amplitude variations of SEM seismograms are measured in the period range of 50--200 s using boxcar taper, cosine taper and Slepian multi-tapers. We calculate ray-theoretical predictions of surface-wave amplitude perturbations due to elastic focusing, attenuation, and anelastic focusing which respectively depend upon the second spatial derivative (''roughness'') of perturbations in phase velocity, 1/Q, and the roughness of perturbations in 1/Q. Both numerical experiments and theoretical calculations show that (1) for short-period (~ 50 s) surface waves, the effects of amplitude attenuation due to 3-D Q structures are comparable with elastic focusing effects due to 3-D wave speed structures; and (2) for long-period (> 100 s) surface waves, the effects of attenuation become much weaker than elastic focusing; and (3) elastic focusing effects are correlated with anelastic focusing at all periods due to the correlation between velocity and Q models; and (4) amplitude perturbations are depend on measurement techniques and therefore cannot be directly compared with ray-theoretical predictions because ray theory does not account for the effects of measurement

  19. 3D finite element simulations of high velocity projectile impact

    NASA Astrophysics Data System (ADS)

    Ožbolt, Joško; İrhan, Barış; Ruta, Daniela

    2015-09-01

    An explicit three-dimensional (3D) finite element (FE) code is developed for the simulation of high velocity impact and fragmentation events. The rate sensitive microplane material model, which accounts for large deformations and rate effects, is used as a constitutive law. In the code large deformation frictional contact is treated by forward incremental Lagrange multiplier method. To handle highly distorted and damaged elements the approach based on the element deletion is employed. The code is then used in 3D FE simulations of high velocity projectile impact. The results of the numerical simulations are evaluated and compared with experimental results. It is shown that it realistically predicts failure mode and exit velocities for different geometries of plain concrete slab. Moreover, the importance of some relevant parameters, such as contact friction, rate sensitivity, bulk viscosity and deletion criteria are addressed.

  20. Refining the 3D seismic velocity and attenuation models for Katmai National Park, Alaska

    NASA Astrophysics Data System (ADS)

    Murphy, R. A.; Thurber, C. H.; Prejean, S. G.

    2009-12-01

    We invert data from approximately 4,000 local earthquakes occurring between September 2004 and August 2009 to determine the 3D P-wave velocity and P-wave attenuation structures in the Katmai volcanic region. Arrival information and waveforms for the study come from the Alaska Volcano Observatory’s permanent network of 20 seismometers in the area, which are predominantly single-component, short period instruments. The absolute and relative arrival times are used in a double-difference seismic tomography inversion to solve for an improved velocity model for the main volcanic centers. We use the resulting 3D velocity model to relocate all catalog earthquakes in Katmai between January 1996 and August 2009. Inversions for the quality factor Q are completed using a spectral decay approach to determine source parameters, t*, and site response with a nonlinear inversion. Using the final 3D velocity model to define the ray paths, t* values are then inverted to determine frequency-independent Q models. The final models developed through these inversions reveal a low velocity and low Q zone from the surface to ~7 km depth centered on the volcanic axis and extending ~25 km between Martin and Katmai volcanoes. The relocated hypocenters provide insight into the geometry of seismogenic structures in the area, revealing clustering of events into four distinct zones associated with Martin, Mageik, Trident, and Katmai. While the Martin, Mageik, and Katmai clusters are all at 3-4 km depth, the Trident cluster is slightly deeper at 4-6 km. Many new features are apparent within these clusters, including a strand of earthquakes trending NE-SW between the main Martin and Mageik clusters. Smaller linear features are also visible in the Katmai cluster along with a small migrating swarm which occurred NW of the Katmai caldera during mid-2006. Data from an array of 11 three-component broadband instruments currently deployed in the area between Mageik volcano and Katmai caldera will be

  1. Upper-mantle velocities below the Scandinavian Mountains from P- and S-wave traveltime tomography

    NASA Astrophysics Data System (ADS)

    Hejrani, Babak; Balling, Niels; Jacobsen, Bo Holm; England, Richard

    2017-01-01

    The relative traveltime residuals of more than 20 000 arrival times of teleseismic P and S waves measured over a period of more than 10 yr in five separate temporary and two permanent seismic networks covering the Scandinavian (Scandes) Mountains and adjacent areas of the Baltic Shield are inverted to 3-D tomograms of P and S velocities and the VP/VS ratio. Resolution analysis documents that good 3-D resolution is available under the dense network south of 64° latitude (Southern Scandes Mountains), and patchier, but highly useful resolution is available further north, where station coverage is more uneven. A pronounced upper-mantle velocity boundary (UMVB) that transects the study region is defined. It runs from SE Norway (east of the Oslo Graben) across the mountains to the Norwegian coast near Trondheim (around the Møre-Trøndelag Fault Complex), after which it follows closely along the coast further north. Seismic velocities in the depth interval 100-300 km change significantly across the UMVB from low relative VP and even lower relative VS on the western side, to high relative VP and even higher relative VS to the east. This main velocity boundary therefore also separates relatively high VP/VS ratio to the west and relatively low VP/VS to the east. Under the Southern Scandes Mountains (most of southern Norway), we find low relative VP, even lower relative VS and hence high VP/VS ratios. These velocities are indicative of thinner lithosphere, higher temperature and less depletion and/or fluid content in a relatively shallow asthenosphere. At first sight, this might support the idea of a mantle buoyancy source for the high topography. Under the Northern Scandes Mountains, we find the opposite situation: high relative VP, even higher relative VS and hence low VP/VS ratios, consistent with thick, dry, depleted lithosphere, similar to that in most of the Baltic Shield area. This demonstrates significant differences in upper-mantle conditions between the Southern

  2. Upper-mantle velocities below the Scandinavian Mountains from P- and S- wave traveltime tomography

    NASA Astrophysics Data System (ADS)

    Hejrani, Babak; Balling, Niels; Jacobsen, Bo Holm; England, Richard

    2016-09-01

    The relative traveltime residuals of more than 20,000 arrival-times of teleseismic P- and S-waves measured over a period of more than 10 years in five separate temporary and two permanent seismic networks covering the Scandinavian (Scandes) Mountains and adjacent areas of the Baltic Shield are inverted to 3D tomograms of P- and S- velocities and the VP/VS ratio. Resolution analysis documents that good 3D resolution is available under the dense network south of 64° latitude (Southern Scandes Mountains), and patchier, but highly useful resolution is available further north, where station coverage is more uneven. A pronounced upper-mantle velocity boundary (UMVB) that transects the study region is defined. It runs from SE Norway (east of the Oslo Graben) across the mountains to the Norwegian coast near Trondheim (around the Møre-Trøndelag Fault Complex), after which it follows closely along the coast further north. Seismic velocities in the depth interval 100-300 km change significantly across the UMVB from low relative VP and even lower relative VS on the western side, to high relative VP and even higher relative VS to the east. This main velocity boundary therefore also separates relatively high VP/VS ratio to the west and relatively low VP/VS to the east. Under the Southern Scandes Mountains (most of southern Norway) we find low relative VP, even lower relative VS and hence high VP/VS ratios. These velocities are indicative of thinner lithosphere, higher temperature and less depletion and/or fluid content in a relatively shallow asthenosphere. At first sight, this might support the idea of a mantle buoyancy source for the high topography. Under the Northern Scandes Mountains we find the opposite situation: high relative VP, even higher relative VS and hence low VP/VS ratios, consistent with thick, dry, depleted lithosphere, similar to that in most of the Baltic Shield area. This demonstrates significant differences in upper mantle conditions between the Southern

  3. Detailed p- and s-wave velocity models along the LARSE II transect, Southern California

    USGS Publications Warehouse

    Murphy, J.M.; Fuis, G.S.; Ryberg, T.; Lutter, W.J.; Catchings, R.D.; Goldman, M.R.

    2010-01-01

    Structural details of the crust determined from P-wave velocity models can be improved with S-wave velocity models, and S-wave velocities are needed for model-based predictions of strong ground motion in southern California. We picked P- and S-wave travel times for refracted phases from explosive-source shots of the Los Angeles Region Seismic Experiment, Phase II (LARSE II); we developed refraction velocity models from these picks using two different inversion algorithms. For each inversion technique, we calculated ratios of P- to S-wave velocities (VP/VS) where there is coincident P- and S-wave ray coverage.We compare the two VP inverse velocity models to each other and to results from forward modeling, and we compare the VS inverse models. The VS and VP/VS models differ in structural details from the VP models. In particular, dipping, tabular zones of low VS, or high VP/VS, appear to define two fault zones in the central Transverse Ranges that could be parts of a positive flower structure to the San Andreas fault. These two zones are marginally resolved, but their presence in two independent models lends them some credibility. A plot of VS versus VP differs from recently published plots that are based on direct laboratory or down-hole sonic measurements. The difference in plots is most prominent in the range of VP = 3 to 5 km=s (or VS ~ 1:25 to 2:9 km/s), where our refraction VS is lower by a few tenths of a kilometer per second from VS based on direct measurements. Our new VS - VP curve may be useful for modeling the lower limit of VS from a VP model in calculating strong motions from scenario earthquakes.

  4. Tomographic Imaging of Upper Mantle P- and S-wave Velocity Heterogeneity Beneath the Arabian Peninsula

    NASA Astrophysics Data System (ADS)

    Park, Y.; Nyblade, A. A.; Rodgers, A.; Al-Amri, A.

    2005-12-01

    We have studied the three-dimensional P- and S-wave velocity structure beneath the Arabian Peninsula estimated from teleseismic travel time delay tomography. We have completed travel time measurements and inversion of a data set provided by King Abdulaziz City for Science and Technology (KACST: 21 broadband stations and 4 short-period stations). We augmented the KACST data with delay times measured from permanent Incorporated Research Institutions for Seismology (IRIS) stations in the region (RAYN, EIL and MRNI) and the 1996 Saudi Arabian PASSCAL Experiment (9 broadband stations). We used 401 earthquakes resulting in 3416 ray paths with P- and PKP-wave arrivals for the P-wave tomography, and 1602 ray paths with S- and SKS-wave arrivals came from 201 earthquakes for the S-wave tomography. Although the total number of rays for the S-wave model is a half of the rays for the P-wave model, the event distribution shows better azimuthal coverage. The P and S wave models yield consistent results. The models show strong low velocity regions beneath the southeastern Arabian Shield and the mid-eastern edge of Arabian Shield. The low velocity anomaly in the southeastern part of the Arabian Shield does not extend north of 21°N and dips to south. It likely represents the northeastern edge of the Afar hotspot. The origin of the low velocity region under the eastern edge of the Arabian Shield is uncertain.

  5. Measuring the Stellar Halo Velocity Anisotropy With 3D Kinematics

    NASA Astrophysics Data System (ADS)

    Cunningham, Emily C.; Deason, Alis J.; Guhathakurta, Puragra; Rockosi, Constance M.; van der Marel, Roeland P.; Sohn, S. Tony

    2016-08-01

    We present the first measurement of the anisotropy parameter β using 3D kinematic information outside of the solar neighborhood. Our sample consists of 13 Milky Way halo stars with measured proper motions and radial velocities in the line of sight of M31. Proper motions were measured using deep, multi-epoch HST imaging, and radial velocities were measured from Keck II/DEIMOS spectra. We measure β = -0.3-0.9 +0.4, which is consistent with isotropy, and inconsistent with measurements in the solar neighborhood. We suggest that this may be the kinematic signature of a relatively early, massive accretion event, or perhaps several such events.

  6. S-wave velocity measurements applied to the seismic microzonation of Basel, Upper Rhine Graben

    NASA Astrophysics Data System (ADS)

    Havenith, Hans-Balder; Fäh, Donat; Polom, Ulrich; Roullé, Agathe

    2007-07-01

    An extensive S-wave velocity survey had been carried out in the frame of a recent seismic microzonation study of Basel and the border areas between Switzerland, France and Germany. The aim was to better constrain the seismic amplification potential of the surface layers. The survey included single station (H/V spectral ratios) and ambient vibration array measurements carried out by the Swiss team, as well as active S-wave velocity measurements performed by the German and French partners. This paper is focused on the application of the array technique, which consists in recording ambient vibrations with a number of seismological stations. Several practical aspects related to the field measurements are outlined. The signal processing aims to determine the dispersion curves of surface waves contained in the ambient vibrations. The inversion of the dispersion curve provides a 1-D S-wave velocity model for the investigated site down to a depth related to the size of the array. Since the size of arrays is theoretically not limited, arrays are known to be well adapted for investigations in deep sediment basins, such as the Upper Rhine Graben including the area of the city of Basel. In this region, 27 array measurements with varying station configurations have been carried out to determine the S-wave velocity properties of the geological layers down to a depth of 100-250 m. For eight sites, the outputs of the array measurements have been compared with the results of the other investigations using active sources, the spectral analysis of surface waves (SASW) and S-wave reflection seismics. Borehole information available for a few sites could be used to calibrate the geophysical measurements. By this comparison, the advantages and disadvantages of the array method and the other techniques are outlined with regard to the effectiveness of the methods and the required investigation depth. The dispersion curves measured with the arrays and the SASW technique were also combined

  7. Gas hydrate concentration estimated from P- and S-wave velocities

    NASA Astrophysics Data System (ADS)

    Carcione, J. M.; Gei, D.

    2003-04-01

    We estimate the concentration of gas hydrate at the Mallik 2L-38 research site, Mackenzie Delta, Canada, using P- and S-wave velocities obtained from well logging and vertical seismic profiles (VSP). The theoretical velocities are obtained from a poro-viscoelastic model based on a Biot-type approach. It considers the existence of two solids (grains and gas hydrate) and a fluid mixture and is based on the assumption that hydrate fills the pore space and shows interconnection. The moduli of the matrix formed by gas hydrate are obtained from the percolation model described by Leclaire et al., (1994). An empirical mixing law introduced by Brie et al., (1995) provides the effective bulk modulus of the fluid phase, giving Wood's modulus at low frequency and Voigt's modulus at high frequencies. The dry-rock moduli are estimated from the VSP profile where the rock is assumed to be fully saturated with water, and the quality factors are obtained from the velocity dispersion observed between the sonic and VSP velocities. Attenuation is described by using a constant-Q model for the dry rock moduli. The amount of dissipation is estimated from the difference between the seismic velocities and the sonic-log velocities. We estimate the amount of gas hydrate by fitting the sonic-log and seismic velocities to the theoretical velocities, using the concentration of gas hydrate as fitting parameter. We obtain hydrate concentrations up to 75 %, average values of 43 and 47 % from the VSP P- and S-wave velocities, respectively, and 47 and 42 % from the sonic-log P- and S-wave velocities, respectively. These averages are computed from 897 to 1110 m, excluding the zones where there is no gas hydrate. We found that modeling attenuation is important to obtain reliable results. largeReferences} begin{description} Brie, A., Pampuri, F., Marsala A.F., Meazza O., 1995, Shear Sonic Interpretation in Gas-Bearing Sands, SPE Annual Technical Conference and Exhibition, Dallas, 1995. Carcione, J

  8. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume VI S-Wave Measurements in Borehole C4997 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

    SciTech Connect

    Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

    2007-06-06

    Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (VI), all S-wave measurements are presented that were performed in Borehole C4997 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.

  9. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume V S-Wave Measurements in Borehole C4996 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

    SciTech Connect

    Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

    2007-06-06

    Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (V), all S-wave measurements are presented that were performed in Borehole C4996 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.

  10. 3-D Velocity Measurement of Natural Convection Using Image Processing

    NASA Astrophysics Data System (ADS)

    Shinoki, Masatoshi; Ozawa, Mamoru; Okada, Toshifumi; Kimura, Ichiro

    This paper describes quantitative three-dimensional measurement method for flow field of a rotating Rayleigh-Benard convection in a cylindrical cell heated below and cooled above. A correlation method for two-dimensional measurement was well advanced to a spatio-temporal correlation method. Erroneous vectors, often appeared in the correlation method, was successfully removed using Hopfield neural network. As a result, calculated 3-D velocity vector distribution well corresponded to the observed temperature distribution. Consequently, the simultaneous three-dimensional measurement system for temperature and flow field was developed.

  11. UCVM: Open Source Software for Understanding and Delivering 3D Velocity Models

    NASA Astrophysics Data System (ADS)

    Gill, D.; Small, P.; Maechling, P. J.; Jordan, T. H.; Shaw, J. H.; Plesch, A.; Chen, P.; Lee, E. J.; Taborda, R.; Olsen, K. B.; Callaghan, S.

    2014-12-01

    Physics-based ground motion simulations can calculate the propagation of earthquake waves through 3D velocity models of the Earth. The Southern California Earthquake Center (SCEC) has developed the Unified Community Velocity Model (UCVM) framework to help researchers build structured or unstructured velocity meshes from 3D velocity models for use in wave propagation simulations. The UCVM software framework makes it easy to extract P and S wave propagation speeds and other material properties from 3D velocity models by providing a common interface through which researchers can query earth models for a given location and depth. Currently, the platform supports multiple California models, including SCEC CVM-S4 and CVM-H 11.9.1, and has been designed to support models from any region on earth. UCVM is currently being use to generate velocity meshes for many SCEC wave propagation codes, including AWP-ODC-SGT and Hercules. In this presentation, we describe improvements to the UCVM software. The current version, UCVM 14.3.0, released in March of 2014, supports the newest Southern California velocity model, CVM-S4.26, which was derived from 26 full-3D tomographic iterations using CVM-S4 as the starting model (Lee et al., this meeting), and the Broadband 1D velocity model used in the CyberShake 14.2 study. We have ported UCVM to multiple Linux distributions and OS X. Also included in this release is the ability to add small-scale stochastic heterogeneities to extract Cartesian meshes for use in high-frequency ground motion simulations. This tool was built using the C language open-source FFT library, FFTW. The stochastic parameters (Hurst exponent, correlation length, and the horizontal/vertical aspect ratio) can be customized by the user. UCVM v14.3.0 also provides visualization scripts for constructing cross-sections, horizontal slices, basin depths, and Vs30 maps. The interface allows researchers to visually review velocity models . Also, UCVM v14.3.0 can extract

  12. UCVM: An Open Source Software Package for Querying and Visualizing 3D Velocity Models

    NASA Astrophysics Data System (ADS)

    Gill, D.; Small, P.; Maechling, P. J.; Jordan, T. H.; Shaw, J. H.; Plesch, A.; Chen, P.; Lee, E. J.; Taborda, R.; Olsen, K. B.; Callaghan, S.

    2015-12-01

    Three-dimensional (3D) seismic velocity models provide foundational data for ground motion simulations that calculate the propagation of earthquake waves through the Earth. The Southern California Earthquake Center (SCEC) has developed the Unified Community Velocity Model (UCVM) package for both Linux and OS X. This unique framework provides a cohesive way for querying and visualizing 3D models. UCVM v14.3.0, supports many Southern California velocity models including CVM-S4, CVM-H 11.9.1, and CVM-S4.26. The last model was derived from 26 full-3D tomographic iterations on CVM-S4. Recently, UCVM has been used to deliver a prototype of a new 3D model of central California (CCA) also based on full-3D tomographic inversions. UCVM was used to provide initial plots of this model and will be used to deliver CCA to users when the model is publicly released. Visualizing models is also possible with UCVM. Integrated within the platform are plotting utilities that can generate 2D cross-sections, horizontal slices, and basin depth maps. UCVM can also export models in NetCDF format for easy import into IDV and ParaView. UCVM has also been prototyped to export models that are compatible with IRIS' new Earth Model Collaboration (EMC) visualization utility. This capability allows for user-specified horizontal slices and cross-sections to be plotted in the same 3D Earth space. UCVM was designed to help a wide variety of researchers. It is currently being use to generate velocity meshes for many SCEC wave propagation codes, including AWP-ODC-SGT and Hercules. It is also used to provide the initial input to SCEC's CyberShake platform. For those interested in specific data points, the software framework makes it easy to extract P and S wave propagation speeds and other material properties from 3D velocity models by providing a common interface through which researchers can query earth models for a given location and depth. Also included in the last release was the ability to add small

  13. Visualizing 3D velocity fields near contour surfaces

    SciTech Connect

    Max, N.; Crawfis, R.; Grant, C.

    1994-03-01

    Vector field rendering is difficult in 3D because the vector icons overlap and hide each other. We propose four different techniques for visualizing vector fields only near surfaces. The first uses motion blurred particles in a thickened region around the surface. The second uses a voxel grid to contain integral curves of the vector field. The third uses many antialiased lines through the surface, and the fourth uses hairs sprouting from the surface and then bending in the direction of the vector field. All the methods use the graphite pipeline, allowing real time rotation and interaction, and the first two methods can animate the texture to move in the flow determined by the velocity field.

  14. The USGS 3D Seismic Velocity Model for Northern California

    NASA Astrophysics Data System (ADS)

    Brocher, T. M.; Aagaard, B.; Simpson, R. W.; Jachens, R. C.

    2006-12-01

    We present a new regional 3D seismic velocity model for Northern California for use in strong motion simulations of the 1906 San Francisco and other earthquakes. The model includes compressional-wave velocity (Vp), shear-wave velocity (Vs), density, and intrinsic attenuation (Qp, Qs). These properties were assigned for each rock type in a 3D geologic model derived from surface outcrops, boreholes, gravity and magnetic data, and seismic reflection, refraction, and tomography studies. A detailed description of the model, USGS Bay Area Velocity Model 05.1.0, is available online [http://www.sf06simulation.org/geology/velocitymodel]. For ground motion simulations Vs and Qs are more important parameters than Vp and Qp because the strongest ground motions are generated chiefly by shear and surface wave arrivals. Because Vp data are more common than Vs data, however, we first developed Vp versus depth relations for each rock type and then converted these to Vs versus depth relations. For the most important rock types in Northern California we compiled measurements of Vp versus depth using borehole logs, laboratory measurements on hand samples, seismic refraction profiles, and tomography models. These rock types include Salinian and Sierran granitic rocks, metagraywackes and greenstones of the Franciscan Complex, Tertiary and Mesozoic sedimentary and volcanic rocks, and Quaternary and Holocene deposits (Brocher, USGS OFR 05-1317, 2005). Vp versus depth curves were converted to Vs versus depth curves using new empirical nonlinear relations between Vs and Vp (Brocher, BSSA, 2005). These relations, showing that Poisson's ratio is a nonlinear function of Vp, were similarly based on compilations of diverse Vs and Vp measurements on a large suite of rock types, mainly from California and the Pacific Northwest. The model is distributed in a discretized form with routines to query the model using C++, C, and Fortran 77 programming languages. The geologic model was discretized at

  15. Developing Strength Chart of Saturated Concrete by Using Seismic P and S-Wave Velocities in Laboratory

    NASA Astrophysics Data System (ADS)

    Ekinci, B.; Sabbağ, N.; Uyanik, O.; Öncü, Z.; Akdemir, S.; Türker, E.

    2014-12-01

    Determining of concrete strength can be used by destructive or non-destructive methods. Concrete strength is determined with uniaxial compressive test as destructive in laboratory and with Seismic Ultrasonic P- (Compressional) and S-wave (Shear) measurements as non-destructive in-situ or laboratory. In this study, strength of saturated concrete is investigated by using seismic P and S-wave velocities. For this, concrete samples were formed with using the cube samples in size 15x15x15cm. Different strength designs were made for obtain different strengths in these samples. The aim is to create concrete strengths of between the lowest 5MPa and the highest 100 MPa. After the end of the curing time of created the cube concrete samples Seismic P and S waves measurements were made in the laboratory by Ultrasonic test equipment. Hence, P and S wave velocities of the sample were calculated. After these, for determine the strength of the samples uniaxial compression strength test was performed. As a result, P and S wave velocities and concrete strength values of concrete samples were obtained. By correlating these values over %90 exponential relationships were determined. By using this relationship, concrete strength can be determined sensitively from P and S wave velocities. In addition, by using P and S wave velocities elastic parameters values and Poisson's ratio of concrete specimens can be calculated. Keywords: Concrete, Strength, Compressional and Shear-wave velocities, Empirical Relationship

  16. Amplitude Anomalies of S Waves Caused by Low Shear Velocity Structures at the Base of the Mantle

    NASA Astrophysics Data System (ADS)

    To, A.; Capdeville, Y.; Romanowicz, B. A.

    2015-12-01

    Previous studies have shown that the direct S and Sdiff waveforms of earthquakes in Papua New Guinea region recorded by seismographs in Northern America are distorted due to sampling slow shear velocity anomalies at the base of the mantle. The emergence of postcursours to the S/Sdiff waves and the travel time anomalies have been reasonably explained by placing a ultra low velocity zone (ULVZ) in southwest of Hawaii. In this study, we focused on the amplitude anomalies of the S/Sdiff waveforms. The direct S phase show very low amplitude at stations in Southern California, at the distance and azimuth around 90 and 55 degrees from the earthquake. The amplitude is as low as 10% of the synthetic amplitude of a standard 1D model, especially at higher frequency range above 0.025 Hz. We first checked and confirmed that the anomalies are not due to errors in the focal mechanism, which is used to calculate the reference synthetic waveforms. Also we checked that the amplitude anomalies are unlikely to be caused by the structures near the earthquake or near the stations, by looking at the amplitude of the depth phases or waveforms of other earthquakes. We assumed that the anomalies are produced by the focusing and defocusing effect of sampling 3D heterogeneous at the base of the mantle, and searched for the causal structures. Full 3D synthetic waveforms are calculated down to 8 seconds for tens of structural models with slow anomalies of different size and velocity reduction placed on the core-mantle boundary (CMB). The result shows that existing tomographic models do not fully explain the observed amplitude anomalies. Stronger shear velocity anomalies are required. The previously proposed thin large ULVZ placed on the CMB southwest of Hawaii partly explains the observed amplitude reduction, even at the distance as short as 90 degrees from the earthquake. This result indicates the significance of finite frequency effect of the ULVZ structure to the S waves, since the ray

  17. Vel-IO 3D: A tool for 3D velocity model construction, optimization and time-depth conversion in 3D geological modeling workflow

    NASA Astrophysics Data System (ADS)

    Maesano, Francesco E.; D'Ambrogi, Chiara

    2017-02-01

    We present Vel-IO 3D, a tool for 3D velocity model creation and time-depth conversion, as part of a workflow for 3D model building. The workflow addresses the management of large subsurface dataset, mainly seismic lines and well logs, and the construction of a 3D velocity model able to describe the variation of the velocity parameters related to strong facies and thickness variability and to high structural complexity. Although it is applicable in many geological contexts (e.g. foreland basins, large intermountain basins), it is particularly suitable in wide flat regions, where subsurface structures have no surface expression. The Vel-IO 3D tool is composed by three scripts, written in Python 2.7.11, that automate i) the 3D instantaneous velocity model building, ii) the velocity model optimization, iii) the time-depth conversion. They determine a 3D geological model that is consistent with the primary geological constraints (e.g. depth of the markers on wells). The proposed workflow and the Vel-IO 3D tool have been tested, during the EU funded Project GeoMol, by the construction of the 3D geological model of a flat region, 5700 km2 in area, located in the central part of the Po Plain. The final 3D model showed the efficiency of the workflow and Vel-IO 3D tool in the management of large amount of data both in time and depth domain. A 4 layer-cake velocity model has been applied to a several thousand (5000-13,000 m) thick succession, with 15 horizons from Triassic up to Pleistocene, complicated by a Mesozoic extensional tectonics and by buried thrusts related to Southern Alps and Northern Apennines.

  18. Tomographic Imaging of Upper Mantle P- and S-wave Velocity Heterogeneity Beneath the Arabian Peninsula

    SciTech Connect

    Park, Y; Nyblade, A; Rodgers, A; Al-Amri, A

    2005-08-30

    We report the estimates of three-dimensional P- and S-wave velocity structure beneath the Arabian Peninsula estimated from travel time delay tomography. We have completed travel time measurements and inversion of a partial data set provided by King Abdulaziz City for Science and Technology (KACST). This study builds on previous work by Benoit et al. (2003) following the methods of VanDecar and Crosson (1990) and VanDecar (1991). Data were collected from the Saudi Arabian National Digital Seismic Network (SANDSN) operated by KACST. The network consists of 38 stations (27 broadband and 11 short-period). We augmented the KACST data with delay times measured from permanent Incorporated Research Institutions for Seismology (IRIS) stations in the region (RAYN, EIL and MRNI) and the 1996 Saudi Arabian PASSCAL Experiment. This study shows the inverted P- and S-wave models computed with the combined data with all three different seismic networks (KASCST, IRIS, and the 1996 Saudi Arabian PASSCAL experiment) with best coverage beneath the Arabian Shield. Tomographic images reveal low velocity features in the upper mantle along a north-south line from the southern Asir region to the northeastern portion of the Arabian Shield.

  19. Oceanic lithospheric S-wave velocities from the analysis of P-wave polarization at the ocean floor

    NASA Astrophysics Data System (ADS)

    Hannemann, Katrin; Krüger, Frank; Dahm, Torsten; Lange, Dietrich

    2016-12-01

    Our knowledge of the absolute S-wave velocities of the oceanic lithosphere is mainly based on global surface wave tomography, local active seismic or compliance measurements using oceanic infragravity waves. The results of tomography give a rather smooth picture of the actual S-wave velocity structure and local measurements have limitations regarding the range of elastic parameters or the geometry of the measurement. Here, we use the P-wave polarization (apparent P-wave incidence angle) of teleseismic events to investigate the S-wave velocity structure of the oceanic crust and the upper tens of kilometres of the mantle beneath single stations. In this study, we present an up to our knowledge new relation of the apparent P-wave incidence angle at the ocean bottom dependent on the half-space S-wave velocity. We analyse the angle in different period ranges at ocean bottom stations (OBSs) to derive apparent S-wave velocity profiles. These profiles are dependent on the S-wave velocity as well as on the thickness of the layers in the subsurface. Consequently, their interpretation results in a set of equally valid models. We analyse the apparent P-wave incidence angles of an OBS data set which was collected in the Eastern Mid Atlantic. We are able to determine reasonable S-wave-velocity-depth models by a three-step quantitative modelling after a manual data quality control, although layer resonance sometimes influences the estimated apparent S-wave velocities. The apparent S-wave velocity profiles are well explained by an oceanic PREM model in which the upper part is replaced by four layers consisting of a water column, a sediment, a crust and a layer representing the uppermost mantle. The obtained sediment has a thickness between 0.3 and 0.9 km with S-wave velocities between 0.7 and 1.4 km s-1. The estimated total crustal thickness varies between 4 and 10 km with S-wave velocities between 3.5 and 4.3 km s-1. We find a slight increase of the total crustal thickness from

  20. Uncertainty assessment of 3D instantaneous velocity model from stack velocities

    NASA Astrophysics Data System (ADS)

    Emanuele Maesano, Francesco; D'Ambrogi, Chiara

    2015-04-01

    3D modelling is a powerful tool that is experiencing increasing applications in data analysis and dissemination. At the same time the need of quantitative uncertainty evaluation is strongly requested in many aspects of the geological sciences and by the stakeholders. In many cases the starting point for 3D model building is the interpretation of seismic profiles that provide indirect information about the geology of the subsurface in the domain of time. The most problematic step in the 3D modelling construction is the conversion of the horizons and faults interpreted in time domain to the depth domain. In this step the dominant variable that could lead to significantly different results is the velocity. The knowledge of the subsurface velocities is related mainly to punctual data (sonic logs) that are often sparsely distributed in the areas covered by the seismic interpretation. The extrapolation of velocity information to wide extended horizons is thus a critical step to obtain a 3D model in depth that can be used for predictive purpose. In the EU-funded GeoMol Project, the availability of a dense network of seismic lines (confidentially provided by ENI S.p.A.) in the Central Po Plain, is paired with the presence of 136 well logs, but few of them have sonic logs and in some portion of the area the wells are very widely spaced. The depth conversion of the 3D model in time domain has been performed testing different strategies for the use and the interpolation of velocity data. The final model has been obtained using a 4 layer cake 3D instantaneous velocity model that considers both the initial velocity (v0) in every reference horizon and the gradient of velocity variation with depth (k). Using this method it is possible to consider the geological constraint given by the geometries of the horizons and the geo-statistical approach to the interpolation of velocities and gradient. Here we present an experiment based on the use of set of pseudo-wells obtained from the

  1. S-wave velocity self-adaptive prediction based on a variable dry rock frame equivalent model

    NASA Astrophysics Data System (ADS)

    Feng-Ying, Yang; Xing-Yao, Yin; Bo, Liu

    2014-08-01

    Seismic velocities are important reservoir parameters in seismic exploration. The Gassmann theory has been widely used to predict velocities of fluid-saturated isotropic reservoirs at low frequency. According to Gassmann theory, dry rock frame moduli are essential input parameters for estimating reservoir velocities. A variable dry rock frame equivalent model called VDEM based on the differential effective medium (DEM) theory is constructed in this paper to obtain the dry rock frame moduli. We decouple the DEM equations by introducing variable parameters, then simplify these decoupled equations to get the equivalent dry rock fame model. The predicted dry rock frame moduli by the VDEM are in good agreement with the laboratory data. The VDEM is also utilized to predict S-wave velocity combined with Gassmann theory. A self-adaptive inversion method is applied to fit the variable parameters with the constraint of P-wave velocity from well logging data. The S-wave velocity is estimated from these inversed parameters. A comparison between the self-adaptive method and the Xu-White model on S-wave velocity estimation is made. The results corroborate that the self-adaptive method is flexible and effective for S-wave velocity prediction.

  2. P and S Wave Velocity Structure and Vp/Vs Ratios for the New Madrid Seismic Zone

    NASA Astrophysics Data System (ADS)

    Dunn, M.; Deshon, H.; Powell, C.

    2008-12-01

    Three dimensional P and S wave velocity models have been constructed for the New Madrid Seismic Zone (NMSZ) using double difference local earthquake tomography (tomoDD). TomoDD incorporates catalog arrival times with catalog and waveform cross correlation differential times to solve for P and S wave velocity and for high resolution earthquake locations. For the NMSZ, we utilized 101504 P wave differential times and 67811 S wave differential times from 1157 earthquakes recorded over the time period 2000 to 2007 by the Cooperative NMSZ Network. The NMSZ consists of three intersecting arms of seismicity located in the central United States. There are approximately 200 earthquakes a year in the NMSZ despite the absence of a major plate boundary. Most earthquakes occur along the central Reelfoot Fault leading to uneven source distribution. We use a finite difference travel time calculator combined with an irregular inversion grid of nodes spaced every 5 to 20 kilometers horizontally and 1 to 3 kilometers vertically. Model resolution was examined using chessboard and spike tests and indicated that resolution is highest close to the source region between depths of 5 to 12 kilometers. P and S wave models indicate that velocities close to the source region are slightly low relative to the 1D starting model. The decrease in velocities may be indicative of rock properties, such as increased fluid content and fracturing. A high P and S wave velocity anomaly located away from known faults is associated with a known mafic intrusion to the northwest of seismicity.

  3. Velocity and Density Models Incorporating the Cascadia Subduction Zone for 3D Earthquake Ground Motion Simulations

    USGS Publications Warehouse

    Stephenson, William J.

    2007-01-01

    INTRODUCTION In support of earthquake hazards and ground motion studies in the Pacific Northwest, three-dimensional P- and S-wave velocity (3D Vp and Vs) and density (3D rho) models incorporating the Cascadia subduction zone have been developed for the region encompassed from about 40.2?N to 50?N latitude, and from about -122?W to -129?W longitude. The model volume includes elevations from 0 km to 60 km (elevation is opposite of depth in model coordinates). Stephenson and Frankel (2003) presented preliminary ground motion simulations valid up to 0.1 Hz using an earlier version of these models. The version of the model volume described here includes more structural and geophysical detail, particularly in the Puget Lowland as required for scenario earthquake simulations in the development of the Seattle Urban Hazards Maps (Frankel and others, 2007). Olsen and others (in press) used the model volume discussed here to perform a Cascadia simulation up to 0.5 Hz using a Sumatra-Andaman Islands rupture history. As research from the EarthScope Program (http://www.earthscope.org) is published, a wealth of important detail can be added to these model volumes, particularly to depths of the upper-mantle. However, at the time of development for this model version, no EarthScope-specific results were incorporated. This report is intended to be a reference for colleagues and associates who have used or are planning to use this preliminary model in their research. To this end, it is intended that these models will be considered a beginning template for a community velocity model of the Cascadia region as more data and results become available.

  4. The 3D velocity structure beneath Iceland: Identifying melt pathways

    NASA Astrophysics Data System (ADS)

    Allen, R.

    2003-04-01

    The integration of various seismic datasets, recorded by the broadband HOTSPOT network deployed across Iceland, provides one of the highest resolution studies of the crust and mantle structure associated with a plume-ridge system. The mantle P- and S-velocity models (ICEMAN), derived from teleseismic body-wave and surface wave analysis, show a vertical, cylindrical low velocity anomaly ˜200 km in diameter extending from ˜400 km, the maximum depth of resolution, up to ˜200 km above which low velocity material is present beneath all of Iceland. The maximum P- and S-velocity anomalies of -2% and -4% respectively are found beneath the northwestern edge of Vatnajokull. The crustal S-velocity model (ICECRTb) is constrained by local surface waves, refraction experiments and receiver functions, and shows significant variation in crustal thickness. The thinnest, ˜15 km, crust is found around coastal regions, the thickest crust is beneath northwestern Vatnajokull where it reaches a thickness of 45 km. Within this thick crustal root is a vertical low velocity anomaly connecting the core of the mantle anomaly to horizontal low velocity regions that extend along the western and eastern volcanic zones but not the northern volcanic zone. These crustal low velocity zones are interpreted as regions through which melt is fed from the mantle to shallow magma chambers beneath the rift zones, where crustal formation occurs. The pipework between the core of the mantle anomaly and the southern rift zones is responsible for ˜30 km thick crust. Its absence to the north results in relatively thin, ˜20 km thick, crust.

  5. 3D crustal velocity structure beneath the broadband seismic array in the Gyeongju area of Korea by receiver function analyses

    NASA Astrophysics Data System (ADS)

    Lee, Dong Hun; Lee, Jung Mo; Cho, Hyun-Moo; Kang, Tae-Seob

    2016-10-01

    A temporary seismic array was in operation between October 2010 and March 2013 in the Gyeongju area of Korea. Teleseismic records of the seismic array appropriate for receiver function analysis were collected, and selected seismograms were split into five groups based on epicenters-the Banda-Molucca, Sumatra, Iran, Aleutian, and Vanuatu groups. 1D velocity structures beneath each seismic station were estimated by inverting the stacked receiver functions for possible groups. The inversion was done by applying a genetic algorithm, whereas surface wave dispersion data were used as constraints to avoid non-uniqueness in the inversion. The composite velocity structure was constructed by averaging the velocity structures weighted by the number of receiver functions used in stacking. The uncertainty analysis for the velocity structures showed that the average of 95% confidence intervals was ± 0.1 km/s. The 3D velocity structure was modeled through interpolation of 1D composite velocity structures. Moho depths were determined in each composite velocity structure based on the AK135-F S-wave velocity model, and the depths were similar to the H-κ analysis results. The deepest Moho depth in the study area was found to be 31.9 km, and the shallowest, was 25.9 km. The Moho discontinuity dips in a southwestward direction beneath the area. A low velocity layer was also detected between 4 and 14 km depth. Adakitic intrusions and/or a high geothermal gradient appear to be the causes of this low velocity layer. The 3D velocity structure can be used to reliably assess seismic hazards in this area.

  6. Three dimensional P- and S-wave velocity structure along the central Alpine Fault, South Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Guo, B.; Thurber, C. H.; Roecker, S. W.; Townend, J.; Rawles, C.; Chamberlain, C. J.; Boese, C. M.; Bannister, S.; Feenstra, J.; Eccles, J. D.

    2017-02-01

    The Deep Fault Drilling Project (DFDP) on the central Alpine Fault, South Island, New Zealand, has motivated a broad range of geophysical and geological studies intended to characterize the fault system in the locality of the drill site at various scales. In order to better understand the structural features of the central Alpine Fault, we have developed three-dimensional P- and S-wave velocity (VP and VS) models of the region by double-difference tomography using datasets from multiple seismic networks. In previous work, the quality of the S-wave model has been poor due to the small number of available S-wave picks. We have utilized a new high-accuracy automatic S-wave picker to increase the number of usable S-wave arrivals by more than a factor of two, thereby substantially improving the VS model. Compared to previous studies, our new higher-resolution VP model based on more observations shows a clear VP contrast (higher VP on the southeast hanging wall side) at depths of 5 - 10 km near the DFDP drill sites. With our better resolved VS model, in the same region, we detect a sharply defined high VS body (VS > 3.7 km/s) within the hanging wall. Our earthquake relocations reveal the presence of clusters within and around low-velocity zones in the hanging wall southeast of the Alpine Fault. Together with the improved earthquake locations, the P- and S-wave tomography results reveal the Alpine Fault to be marked by a velocity contrast throughout most of the study region. The fault dips southeastward at about 50^circ from 5 to 15 km depth, as inferred from the velocity structure, seismicity, and observations of fault zone guided waves.

  7. Seismicity and S-wave velocity structure of the crust and the upper mantle in the Baikal rift and adjacent regions

    NASA Astrophysics Data System (ADS)

    Seredkina, Alena; Kozhevnikov, Vladimir; Melnikova, Valentina; Solovey, Oksana

    2016-12-01

    Correlations between seismicity, seismotectonic deformation (STD) field and velocity structure of the crust and the upper mantle in the Baikal rift and the adjacent areas of the Siberian platform and the Mongol-Okhotsk fold belt have been investigated. The 3D S-wave velocity structure up to the depths of 500 km has been modeled using a representative sample of Rayleigh wave group velocity dispersion curves (about 3200 paths) at periods from 10 to 250 s. The STD pattern has been reconstructed from mechanisms of large earthquakes, and is in good agreement with GPS and structural data. Analysis of the results has shown that most of large shallow earthquakes fall in regions of low S-wave velocities in the uppermost mantle (western Mongolia and areas of recent mountain building in southern Siberia) and in zones of their relatively high lateral variations (northeastern flank of the Baikal rift). In the first case the dominant STD regime is compression manifested in a mixture of thrust and strike-slip deformations. In the second case we observe a general predominance of extension.

  8. Enhanced zero-bias conductance peak and splitting at mesoscopic interfaces between an s-wave superconductor and a 3D Dirac semimetal

    NASA Astrophysics Data System (ADS)

    Aggarwal, Leena; Gayen, Sirshendu; Das, Shekhar; Thakur, Gohil S.; Ganguli, Ashok K.; Sheet, Goutam

    2016-12-01

    Mesoscopic point contacts between elemental metals and the topological 3D Dirac semimetal Cd3As2 have been recently shown to be superconducting with unconventional pairing while Cd3As2 itself does not superconduct. Here we show that the same superconducting phase at mesoscopic interfaces on Cd3As2 can be induced with a known conventional superconductor Nb where a pronounced zero-bias conductance peak is observed which undergoes splitting in energy under certain conditions. The observations are consistent with the theory of the emergence of Andreev bound states due to the presence of a pair potential with broken time reversal symmetry. The data also indicate the possibility of Majorana bound states as expected at the interfaces between s-wave superconductors and topologically non-trivial materials with a high degree of spin-orbit coupling.

  9. Estimation of shallow S-wave velocity structure in the Puli basin, Taiwan, using array measurements of microtremors

    NASA Astrophysics Data System (ADS)

    Wu, Cheng-Feng; Huang, Huey-Chu

    2012-05-01

    The September 21, 1999, Chi-Chi earthquake induced strong shaking, resulting in severe damage in the Puli area. According to Huang and Tarng (2005), the collapse of many structures during the earthquake was very closely related to site effects. Shallow shear-wave velocities are widely used for earthquake ground-motion site characterization. Thus, we investigate S-wave velocity structures for the Puli area by performing microtremor array measurements at 16 sites. Dispersion curves at these sites are calculated using the F-K method (Capon, 1969) for the vertical component; S-wave velocity structures for the Puli area are then estimated by surface wave inversion (Herrmann, 1991). If the S-wave velocity of the bedrock is assumed to be 2000 m/s, the depths of the Quaternary sediments in the Puli area are between 300 m (FAL, PIP) and 870 m (DAH). Moreover, there are 3˜6 distinct interfaces in the shallow velocity structure (0˜1000 m). The depth of the bedrock gradually increases from the edge (SIN, PIP) to the center (PUL, DAH) of the basin and the thickest Quaternary sediments appear near Heng-Chih-Cheng (DAH).

  10. Measurements of 3D slip velocities and plasma column lengths of a gliding arc discharge

    SciTech Connect

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas; Aldén, Marcus; Li, Zhongshan E-mail: alpers@ma.tum.de; Moseev, Dmitry; Kusano, Yukihiro; Salewski, Mirko; Alpers, Andreas E-mail: alpers@ma.tum.de; Gritzmann, Peter; Schwenk, Martin

    2015-01-26

    A non-thermal gliding arc discharge was generated at atmospheric pressure in an air flow. The dynamics of the plasma column and tracer particles were recorded using two synchronized high-speed cameras. Whereas the data analysis for such systems has previously been performed in 2D (analyzing the single camera image), we provide here a 3D data analysis that includes 3D reconstructions of the plasma column and 3D particle tracking velocimetry based on discrete tomography methods. The 3D analysis, in particular, the determination of the 3D slip velocity between the plasma column and the gas flow, gives more realistic insight into the convection cooling process. Additionally, with the determination of the 3D slip velocity and the 3D length of the plasma column, we give more accurate estimates for the drag force, the electric field strength, the power per unit length, and the radius of the conducting zone of the plasma column.

  11. Comparison of P- and S-wave velocity profiles obtained from surface seismic refraction/reflection and downhole data

    USGS Publications Warehouse

    Williams, R.A.; Stephenson, W.J.; Odum, J.K.

    2003-01-01

    High-resolution seismic-reflection/refraction data were acquired on the ground surface at six locations to compare with near-surface seismic-velocity downhole measurements. Measurement sites were in Seattle, WA, the San Francisco Bay Area, CA, and the San Fernando Valley, CA. We quantitatively compared the data in terms of the average shear-wave velocity to 30-m depth (Vs30), and by the ratio of the relative site amplification produced by the velocity profiles of each data type over a specified set of quarter-wavelength frequencies. In terms of Vs30, similar values were determined from the two methods. There is <15% difference at four of the six sites. The Vs30 values at the other two sites differ by 21% and 48%. The relative site amplification factors differ generally by less than 10% for both P- and S-wave velocities. We also found that S-wave reflections and first-arrival phase delays are essential for identifying velocity inversions. The results suggest that seismic reflection/refraction data are a fast, non-invasive, and less expensive alternative to downhole data for determining Vs30. In addition, we emphasize that some P- and S-wave reflection travel times can directly indicate the frequencies of potentially damaging earthquake site resonances. A strong correlation between the simple S-wave first-arrival travel time/apparent velocity on the ground surface at 100 m offset from the seismic source and the Vs30 value for that site is an additional unique feature of the reflection/refraction data that could greatly simplify Vs30 determinations. ?? 2003 Elsevier Science B.V. All rights reserved.

  12. Poroelastic Wave Propagation With a 3D Velocity-Stress-Pressure Finite-Difference Algorithm

    NASA Astrophysics Data System (ADS)

    Aldridge, D. F.; Symons, N. P.; Bartel, L. C.

    2004-12-01

    Seismic wave propagation within a three-dimensional, heterogeneous, isotropic poroelastic medium is numerically simulated with an explicit, time-domain, finite-difference algorithm. A system of thirteen, coupled, first-order, partial differential equations is solved for the particle velocity vector components, the stress tensor components, and the pressure associated with solid and fluid constituents of the two-phase continuum. These thirteen dependent variables are stored on staggered temporal and spatial grids, analogous to the scheme utilized for solution of the conventional velocity-stress system of isotropic elastodynamics. Centered finite-difference operators possess 2nd-order accuracy in time and 4th-order accuracy in space. Seismological utility is enhanced by an optional stress-free boundary condition applied on a horizontal plane representing the earth's surface. Absorbing boundary conditions are imposed on the flanks of the 3D spatial grid via a simple wavefield amplitude taper approach. A massively parallel computational implementation, utilizing the spatial domain decomposition strategy, allows investigation of large-scale earth models and/or broadband wave propagation within reasonable execution times. Initial algorithm testing indicates that a point force density and/or moment density source activated within a poroelastic medium generates diverging fast and slow P waves (and possibly an S-wave)in accord with Biot theory. Solid and fluid particle velocities are in-phase for the fast P-wave, whereas they are out-of-phase for the slow P-wave. Conversions between all wave types occur during reflection and transmission at interfaces. Thus, although the slow P-wave is regarded as difficult to detect experimentally, its presence is strongly manifest within the complex of waves generated at a lithologic or fluid boundary. Very fine spatial and temporal gridding are required for high-fidelity representation of the slow P-wave, without inducing excessive

  13. COMBINING A NEW 3-D SEISMIC S-WAVE PROPAGATION ANALYSIS FOR REMOTE FRACTURE DETECTION WITH A ROBUST SUBSURFACE MICROFRACTURE-BASED VERIFICATION TECHNIQUE

    SciTech Connect

    Bob Hardage; M.M. Backus; M.V. DeAngelo; R.J. Graebner; S.E. Laubach; Paul Murray

    2004-02-01

    Fractures within the producing reservoirs at McElroy Field could not be studied with the industry-provided 3C3D seismic data used as a cost-sharing contribution in this study. The signal-to-noise character of the converted-SV data across the targeted reservoirs in these contributed data was not adequate for interpreting azimuth-dependent data effects. After illustrating the low signal quality of the converted-SV data at McElroy Field, the seismic portion of this report abandons the McElroy study site and defers to 3C3D seismic data acquired across a different fractured carbonate reservoir system to illustrate how 3C3D seismic data can provide useful information about fracture systems. Using these latter data, we illustrate how fast-S and slow-S data effects can be analyzed in the prestack domain to recognize fracture azimuth, and then demonstrate how fast-S and slow-S data volumes can be analyzed in the poststack domain to estimate fracture intensity. In the geologic portion of the report, we analyze published regional stress data near McElroy Field and numerous formation multi-imager (FMI) logs acquired across McElroy to develop possible fracture models for the McElroy system. Regional stress data imply a fracture orientation different from the orientations observed in most of the FMI logs. This report culminates Phase 2 of the study, ''Combining a New 3-D Seismic S-Wave Propagation Analysis for Remote Fracture Detection with a Robust Subsurface Microfracture-Based Verification Technique''. Phase 3 will not be initiated because wells were to be drilled in Phase 3 of the project to verify the validity of fracture-orientation maps and fracture-intensity maps produced in Phase 2. Such maps cannot be made across McElroy Field because of the limitations of the available 3C3D seismic data at the depth level of the reservoir target.

  14. Estimations of the S-wave velocity structures in Chia-Yi City, Taiwan, using the array records of microtremors

    NASA Astrophysics Data System (ADS)

    Huang, H.-C.; Wu, C.-F.

    2006-11-01

    Shear-wave velocities (VS) have been widely used for the site characterization of earthquake ground motion. We report here our investigation of the S-wave velocity structures of Chia-Yi City, Taiwan using the array records of microtremors at seven sites. The dispersion curves at these sites were first calculated using the F-K method proposed by Capon (1969); the S-wave velocity structures in Chia-Yi City were then estimated by employing the surface wave inversion technique (Herrmann, 1991). At frequencies lower than about 1 Hz, the propagation directions are concentrated in the northwest and southwest quadrants. The generation of these may be attributed to the ocean waves of the Taiwan Strait. The harder site (CBA) has higher phase velocities, while the softer sites (CWB, SHP and YRU) have lower phase velocities, especially at frequencies between 1 and 5 Hz. The shallow velocity structures (0-1,500 m) can be roughly divided into four to five layers. The depth of the alluvium gradually increases from east to west and from north to south.

  15. S-wave velocity structures and Vp/Vs ratios beneath the South Yellow Sea from ocean bottom seismograph data

    NASA Astrophysics Data System (ADS)

    Zhao, Weina; Zhang, Xunhua; Meng, Xiangjun; Wu, Zhiqiang; Qi, Jianghao; Hao, Tianyao; Zheng, Yanpeng; Kai, Liu

    2017-04-01

    In 2013, a wide-angle seismic survey (OBS2013) was conducted perpendicular to the south coast of the Shandong Peninsula in China, to investigate the crustal structure of the South Yellow Sea (SYS). Previous interpretation of the crustal structure of SYS did not use S-wave and Vp/Vs ratios as a constraint. In this study, we constructed the converted S-wave velocity model and Vp/Vs ratios of the northern SYS. Many receiver gathers showed good reflected and refracted S-phases, particularly in the Qianliyan Uplift. The S-wave crustal structure and Vp/Vs ratios were obtained based on a previous P-wave model which utilized RayInvr software by adjusting travel times. Results demonstrated that the S-wave velocities increased with depth, as in the P-wave model. This paper provided a lithologic interpretation of the velocity model. In the uppermost layer beneath the water, most Vp/Vs ratios were high (> 3). The nappe beneath the northwestern OBS2013 mainly consisted of granite and felsic gneiss. In the North Depression (ND), the Vp/Vs ratios of the marine sedimentary layer displayed the characteristics of carbonate rock. However, in the southeast of the ND, the sediment beneath the continental deposit layer was most likely composed of sandstone. The marine sedimentation in the Central Uplift (CU) mainly probably consisted of carbonate rocks with sandstone. Lack of strata with rich sand in the Permian and Triassic period suggested there was a more drastic uplift in the ND than the one in the CU during the Indo-Chinese epoch.

  16. An industrial light-field camera applied for 3D velocity measurements in a slot jet

    NASA Astrophysics Data System (ADS)

    Seredkin, A. V.; Shestakov, M. V.; Tokarev, M. P.

    2016-10-01

    Modern light-field cameras have found their application in different areas like photography, surveillance and quality control in industry. A number of studies have been reported relatively low spatial resolution of 3D profiles of registered objects along the optical axis of the camera. This article describes a method for 3D velocity measurements in fluid flows using an industrial light-field camera and an alternative reconstruction algorithm based on a statistical approach. This method is more accurate than triangulation when applied for tracking small registered objects like tracer particles in images. The technique was used to measure 3D velocity fields in a turbulent slot jet.

  17. Effects of 3D random correlated velocity perturbations on predicted ground motions

    USGS Publications Warehouse

    Hartzell, S.; Harmsen, S.; Frankel, A.

    2010-01-01

    Three-dimensional, finite-difference simulations of a realistic finite-fault rupture on the southern Hayward fault are used to evaluate the effects of random, correlated velocity perturbations on predicted ground motions. Velocity perturbations are added to a three-dimensional (3D) regional seismic velocity model of the San Francisco Bay Area using a 3D von Karman random medium. Velocity correlation lengths of 5 and 10 km and standard deviations in the velocity of 5% and 10% are considered. The results show that significant deviations in predicted ground velocities are seen in the calculated frequency range (≤1 Hz) for standard deviations in velocity of 5% to 10%. These results have implications for the practical limits on the accuracy of scenario ground-motion calculations and on retrieval of source parameters using higher-frequency, strong-motion data.

  18. Theoretical and numerical comparison of 3D numerical schemes for their accuracy with respect to P-wave to S-wave speed ratio

    NASA Astrophysics Data System (ADS)

    Moczo, P.; Kristek, J.; Galis, M.; Chaljub, E.; Chen, X.; Zhang, Z.

    2012-04-01

    Numerical modeling of earthquake ground motion in sedimentary basins and valleys often has to account for the P-wave to S-wave speed ratios (VP/VS) as large as five and even larger, mainly in sediments below groundwater level. The ratio can attain values larger than 10 - the unconsolidated lake sediments in Ciudad de México are a good example. At the same time, accuracy of the numerical schemes with respect to VP/VS has not been sufficiently analyzed. The numerical schemes are often applied without adequate check of the accuracy. We present theoretical analysis and numerical comparison of 18 3D numerical time-domain explicit schemes for modeling seismic motion for their accuracy with the varying VP/VS. The schemes are based on the finite-difference, spectral-element, finite-element and discontinuous-Galerkin methods. All schemes are presented in a unified form. Theoretical analysis compares accuracy of the schemes in terms of local errors in amplitude and vector difference. In addition to the analysis we compare numerically simulated seismograms with exact solutions for canonical configurations. We compare accuracy of the schemes in terms of the local errors, grid dispersion and full wavefield simulations with respect to the structure of the numerical schemes.

  19. 3-D Velocity Model of the Coachella Valley, Southern California Based on Explosive Shots from the Salton Seismic Imaging Project

    NASA Astrophysics Data System (ADS)

    Persaud, P.; Stock, J. M.; Fuis, G. S.; Hole, J. A.; Goldman, M.; Scheirer, D. S.

    2014-12-01

    We have analyzed explosive shot data from the 2011 Salton Seismic Imaging Project (SSIP) across a 2-D seismic array and 5 profiles in the Coachella Valley to produce a 3-D P-wave velocity model that will be used in calculations of strong ground shaking. Accurate maps of seismicity and active faults rely both on detailed geological field mapping and a suitable velocity model to accurately locate earthquakes. Adjoint tomography of an older version of the SCEC 3-D velocity model shows that crustal heterogeneities strongly influence seismic wave propagation from moderate earthquakes (Tape et al., 2010). These authors improve the crustal model and subsequently simulate the details of ground motion at periods of 2 s and longer for hundreds of ray paths. Even with improvements such as the above, the current SCEC velocity model for the Salton Trough does not provide a match of the timing or waveforms of the horizontal S-wave motions, which Wei et al. (2013) interpret as caused by inaccuracies in the shallow velocity structure. They effectively demonstrate that the inclusion of shallow basin structure improves the fit in both travel times and waveforms. Our velocity model benefits from the inclusion of known location and times of a subset of 126 shots detonated over a 3-week period during the SSIP. This results in an improved velocity model particularly in the shallow crust. In addition, one of the main challenges in developing 3-D velocity models is an uneven stations-source distribution. To better overcome this challenge, we also include the first arrival times of the SSIP shots at the more widely spaced Southern California Seismic Network (SCSN) in our inversion, since the layout of the SSIP is complementary to the SCSN. References: Tape, C., et al., 2010, Seismic tomography of the Southern California crust based on spectral-element and adjoint methods: Geophysical Journal International, v. 180, no. 1, p. 433-462. Wei, S., et al., 2013, Complementary slip distributions

  20. 3D velocity measurement by a single camera using Doppler phase-shifting holography

    NASA Astrophysics Data System (ADS)

    Ninomiya, Nao; Kubo, Yamato; Barada, Daisuke; Kiire, Tomohiro

    2016-10-01

    In order to understand the details of the flow field in micro- and nano-fluidic devices, it is necessary to measure the 3D velocities under a microscopy. Thus, there is a strong need for the development of a new measuring technique for 3D velocity by a single camera. One solution is the use of holography, but it is well known that the accuracy in the depth direction is very poor for the commonly used in-line holography. At present, the Doppler phase-shifting holography is used for the 3D measurement of an object. This method extracts the signal of a fixed frequency caused by the Doppler beat between the object light and the reference light. It can measure the 3D shape precisely. Here, the frequency of the Doppler beat is determined by the velocity difference between the object light and the reference light. This implies that the velocity of an object can be calculated by the Doppler frequency. In this study, a Japanese 5 yen coin was traversed at a constant speed and its holography has been observed by a high-speed camera. By extracting only the first order diffraction signal at the Doppler frequency, a precise measurement of the shape and the position of a 5 yen coin has been achieved. At the same time, the longitudinal velocity of a 5 yen coin can be measured by the Doppler frequency. Furthermore, the lateral velocities are obtained by particle image velocimetry (PIV) method. A 5 yen coin has been traversed at different angles and its shapes and the 3D velocities have been measured accurately. This method can be applied to the particle flows in the micro- or nano-devices, and the 3D velocities will be measured under microscopes.

  1. Developing regionalized models of lithospheric thickness and velocity structure across Eurasia and the Middle East from jointly inverting P-wave and S-wave receiver functions with Rayleigh wave group and phase velocities

    SciTech Connect

    Julia, J; Nyblade, A; Hansen, S; Rodgers, A; Matzel, E

    2009-07-06

    In this project, we are developing models of lithospheric structure for a wide variety of tectonic regions throughout Eurasia and the Middle East by regionalizing 1D velocity models obtained by jointly inverting P-wave and S-wave receiver functions with Rayleigh wave group and phase velocities. We expect the regionalized velocity models will improve our ability to predict travel-times for local and regional phases, such as Pg, Pn, Sn and Lg, as well as travel-times for body-waves at upper mantle triplication distances in both seismic and aseismic regions of Eurasia and the Middle East. We anticipate the models will help inform and strengthen ongoing and future efforts within the NNSA labs to develop 3D velocity models for Eurasia and the Middle East, and will assist in obtaining model-based predictions where no empirical data are available and for improving locations from sparse networks using kriging. The codes needed to conduct the joint inversion of P-wave receiver functions (PRFs), S-wave receiver functions (SRFs), and dispersion velocities have already been assembled as part of ongoing research on lithospheric structure in Africa. The methodology has been tested with synthetic 'data' and case studies have been investigated with data collected at an open broadband stations in South Africa. PRFs constrain the size and S-P travel-time of seismic discontinuities in the crust and uppermost mantle, SRFs constrain the size and P-S travel-time of the lithosphere-asthenosphere boundary, and dispersion velocities constrain average S-wave velocity within frequency-dependent depth-ranges. Preliminary results show that the combination yields integrated 1D velocity models local to the recording station, where the discontinuities constrained by the receiver functions are superimposed to a background velocity model constrained by the dispersion velocities. In our first year of this project we will (i) generate 1D velocity models for open broadband seismic stations in the

  2. Tomography 3D models of S wave from cross-correlation of seismic noise to explore irregularities of subsoil under the artificial lake of Chapultepec Park

    NASA Astrophysics Data System (ADS)

    Cárdenas-Soto, M.; Valdes, J. E.; Escobedo-Zenil, D.

    2013-05-01

    In June 2006, the base of the artificial lake in Chapultepec Park collapsed. 20 thousand liters of water were filtered to the ground through a crack increasing the dimensions of initial gap. Studies indicated that the collapse was due to saturated material associated with a sudden and massive water filtration process. Geological studies indicates that all the area of this section the subsoil is composed of vulcano-sedimentary materials that were economically exploited in the mid-20th century, leaving a series of underground mines that were rehabilitated for the construction of the Park. Currently, the Lake is rehabilitated and running for recreational activities. In this study we have applied two methods of seismic noise correlation; seismic interferometry (SI) in time domain and the Spatial Power Auto Correlation (SPAC) in frequency domain, in order to explore the 3D subsoil velocity structure. The aim is to highlight major variations in velocity that can be associated with irregularities in the subsoil that may pose a risk to the stability of the Lake. For this purpose we use 96 vertical geophones of 4.5 Hz with 5-m spacing that conform a semi-circular array that provide a length of 480 m around the lake zone. For both correlation methods, we extract the phase velocity associated with the dispersion characteristics between each pair of stations in the frequency range from 4 to 12 Hz. In the SPAC method the process was through the dispersion curve, and in SI method we use the time delay of the maximum amplitude in the correlation pulse, which was previously filtered in multiple frequency bands. The results of both processes were captured in 3D velocity volumes (in the case SI a process of traveltime tomography was applied). We observed that in the frequency range from 6 to 8 Hz, appear irregular structures, with high velocity contrast in relation with the shear wave velocity of surface layer (ten thick m of saturated sediments). One of these anomalies is related

  3. Representation of 3-D surface orientation by velocity and disparity gradient cues in area MT.

    PubMed

    Sanada, Takahisa M; Nguyenkim, Jerry D; Deangelis, Gregory C

    2012-04-01

    Neural coding of the three-dimensional (3-D) orientation of planar surface patches may be an important intermediate step in constructing representations of complex 3-D surface structure. Spatial gradients of binocular disparity, image velocity, and texture provide potent cues to the 3-D orientation (tilt and slant) of planar surfaces. Previous studies have described neurons in both dorsal and ventral stream areas that are selective for surface tilt based on one or more of these gradient cues. However, relatively little is known about whether single neurons provide consistent information about surface orientation from multiple gradient cues. Moreover, it is unclear how neural responses to combinations of surface orientation cues are related to responses to the individual cues. We measured responses of middle temporal (MT) neurons to random dot stimuli that simulated planar surfaces at a variety of tilts and slants. Four cue conditions were tested: disparity, velocity, and texture gradients alone, as well as all three gradient cues combined. Many neurons showed robust tuning for surface tilt based on disparity and velocity gradients, with relatively little selectivity for texture gradients. Some neurons showed consistent tilt preferences for disparity and velocity cues, whereas others showed large discrepancies. Responses to the combined stimulus were generally well described as a weighted linear sum of responses to the individual cues, even when disparity and velocity preferences were discrepant. These findings suggest that area MT contains a rudimentary representation of 3-D surface orientation based on multiple cues, with single neurons implementing a simple cue integration rule.

  4. The ZH ratio method for long-period seismic data: inversion for S-wave velocity structure

    NASA Astrophysics Data System (ADS)

    Yano, Tomoko; Tanimoto, T.; Rivera, L.

    2009-10-01

    The particle motion of surface waves, in addition to phase and group velocities, can provide useful information for S-wave velocity structure in the crust and upper mantle. In this study, we applied a new method to retrieve velocity structure using the ZH ratio, the ratio between vertical and horizontal surface amplitudes of Rayleigh waves. Analysing data from the GEOSCOPE network, we measured the ZH ratios for frequencies between 0.004 and 0.05 Hz (period between 20 and 250s) and inverted them for S-wave velocity structure beneath each station. Our analysis showed that the resolving power of the ZH ratio is limited and final solutions display dependence on starting models; in particular, the depth of the Moho in the starting model is important in order to get reliable results. Thus, initial models for the inversion need to be carefully constructed. We chose PREM and CRUST2.0 in this study as a starting model for all but one station (ECH). The eigenvalue analysis of the least-squares problem that arises for each step of the iterative process shows a few dominant eigenvalues which explains the cause of the inversion's initial-model dependence. However, the ZH ratio is unique in having high sensitivity to near-surface structure and thus provides complementary information to phase and group velocities. Application of this method to GEOSCOPE data suggest that low velocity zones may exist beneath some stations near hotspots. Our tests with different starting models show that the models with low-velocity anomalies fit better to the ZH ratio data. Such low velocity zones are seen near Hawaii (station KIP), Crozet Island (CRZF) and Djibuti (ATD) but not near Reunion Island (RER). It is also found near Echery (ECH) which is in a geothermal area. However, this method has a tendency to produce spurious low velocity zones and resolution of the low velocity zones requires further careful study. We also performed simultaneous inversions for volumetric perturbation and

  5. Low S-wave-velocity layers in the transition zone: a review of seismic data

    NASA Astrophysics Data System (ADS)

    Vinnik, Lev

    2010-05-01

    I review the seismic data that suggest the presence of thin (a few tens km wide) low-S-velocity zones atop the 410-km discontinuity and in a depth range of 450 - 520 km. Most of the data are obtained with receiver function techniques. Contrary to the prediction of Bercovici and Karato (2003), the low velocity atop the 410-km discontinuity is found mostly in association with plume-like structures in the mantle of the Kaapvaal craton, the Siberian craton, the Arabian plate, West Siberia, China, West Africa and Antarctica (Vinnik and Farra, 2002, 2007). In southern Africa (Vinnik et al.,GJI 2009) this structure seems to be anisotropic. The latest observations of the low velocity atop the 410-km discontinuity are made in the western US and California (e.g. Vinnik et al. JGR 2010, in press). In southern California and the neighboring Pacific this layer, found with the S receiver function techniques, can be related to the Baja-Guadalupe hot-spot. The low velocity can be related to the high solubilty of water in wadsleyite in the mantle transition zone relative to olivine in the overlaying mantle, but other possibilities cannot be excluded. Most observations of the low-velocity zone in a depth range of 450-520 km are also related to plumes and plume-like structures (Afar, Iceland, Azores, Cameroon, south-eastern Atlantic). A plausible theory of this phenomenon should explain why the low S velocity never extends to depths exceeding 520 km.

  6. 3D P-Wave Velocity Structure of the Deep Galicia Rifted Margin

    NASA Astrophysics Data System (ADS)

    Bayrakci, Gaye; Minshull, Timothy; Davy, Richard; Sawyer, Dale; Klaeschen, Dirk; Papenberg, Cord; Reston, Timothy; Shillington, Donna; Ranero, Cesar

    2015-04-01

    The combined wide-angle reflection-refraction and multi-channel seismic (MCS) experiment, Galicia 3D, was carried out in 2013 at the Galicia rifted margin in the northeast Atlantic Ocean, west of Spain. The main geological features within the 64 by 20 km (1280 km²) 3D box investigated by the survey are the peridotite ridge (PR), the fault bounded, rotated basement blocks and the S reflector, which has been interpreted to be a low angle detachment fault. 44 short period four-component ocean bottom seismometers and 28 ocean bottom hydrophones were deployed in the 3D box. 3D MCS profiles sampling the whole box were acquired with two airgun arrays of 3300 cu.in. fired alternately every 37.5 m. We present the results from 3D first-arrival time tomography that constrains the P-wave velocity in the 3D box, for the entire depth sampled by reflection data. Results are validated by synthetic tests and by the comparison with Galicia 3D MCS lines. The main outcomes are as follows: 1- The 3.5 km/s iso-velocity contour mimics the top of the acoustic basement observed on MCS profiles. Block bounding faults are imaged as velocity contrasts and basement blocks exhibit 3D topographic variations. 2- On the southern profiles, the top of the PR rises up to 5.5 km depth whereas, 20 km northward, its basement expression (at 6.5 km depth) nearly disappears. 3- The 6.5 km/s iso-velocity contour matches the topography of the S reflector where the latter is visible on MCS profiles. Within a depth interval of 0.6 km (in average), velocities beneath the S reflector increase from 6.5 km/s to 7 km/s, which would correspond to a decrease in the degree of serpentinization from ~45 % to ~30 % if these velocity variations are caused solely by variations in hydration. At the intersections between the block bounding normal faults and the S reflector, this decrease happens over a larger depth interval (> 1 km), suggesting that faults act as conduit for the water flow in the upper mantle.

  7. 3D P-Wave Velocity Structure of the Deep Galicia Rifted Margin

    NASA Astrophysics Data System (ADS)

    Bayrakci, G.; Minshull, T. A.; Davy, R. G.; Sawyer, D. S.; Klaeschen, D.; Papenberg, C. A.; Reston, T. J.; Shillington, D. J.; Ranero, C. R.

    2014-12-01

    The combined wide-angle reflection-refraction and multi-channel seismic (MCS) experiment, Galicia 3D, was carried out in 2013 at the Galicia rifted margin in the northeast Atlantic Ocean, west of Spain. The main geological features within the 64 by 20 km (1280 km²) 3D box investigated by the survey are the peridotite ridge (PR), the fault bounded, rotated basement blocks and the S reflector, which has been interpreted to be a low angle detachment fault. 44 short period four-component ocean bottom seismometers and 28 ocean bottom hydrophones were deployed in the 3D box. 3D MCS profiles sampling the whole box were acquired with two airgun arrays of 3300 cu.in. fired alternately every 37.5 m. We present the results from 3D first-arrival time tomography that constrains the P-wave velocity in the 3D box, for the entire depth sampled by reflection data. Results are validated by synthetic tests and by the comparison with Galicia 3D MCS lines. The main outcomes are as follows: 1- The 3.5 km/s iso-velocity contour mimics the top of the acoustic basement observed on MCS profiles. Block bounding faults are imaged as velocity contrasts and basement blocks exhibit 3D topographic variations. 2- On the southern profiles, the top of the PR rises up to 5.5 km depth whereas, 20 km northward, its basement expression (at 6.5 km depth) nearly disappears. 3- The 6.5 km/s iso-velocity contour matches the topography of the S reflector where the latter is visible on MCS profiles. Within a depth interval of 0.6 km (in average), velocities beneath the S reflector increase from 6.5 km/s to 7 km/s, which would correspond to a decrease in the degree of serpentinization from ~45 % to ~30 % if these velocity variations are caused solely by variations in hydration. At the intersections between the block bounding normal faults and the S reflector, this decrease happens over a larger depth interval (> 1 km), suggesting that faults act as conduit for the water flow in the upper mantle.

  8. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume IV S-Wave Measurements in Borehole C4993 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

    SciTech Connect

    Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

    2007-06-06

    In this volume (IV), all S-wave measurements are presented that were performed in Borehole C4993 at the Waste Treatment Plant (WTP) with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver. S-wave measurements were performed over the depth range of 370 to 1300 ft, typically in 10-ft intervals. However, in some interbeds, 5-ft depth intervals were used, while below about 1200 ft, depth intervals of 20 ft were used. Shear (S) waves were generated by moving the base plate of T-Rex for a given number of cycles at a fixed frequency as discussed in Section 2. This process was repeated so that signal averaging in the time domain was performed using 3 to about 15 averages, with 5 averages typically used. In addition, a second average shear wave record was recorded by reversing the polarity of the motion of the T-Rex base plate. In this sense, all the signals recorded in the field were averaged signals. In all cases, the base plate was moving perpendicular to a radial line between the base plate and the borehole which is in and out of the plane of the figure shown in Figure 1.1. The definition of “in-line”, “cross-line”, “forward”, and “reversed” directions in items 2 and 3 of Section 2 was based on the moving direction of the base plate. In addition to the LBNL 3-D geophone, called the lower receiver herein, a 3-D geophone from Redpath Geophysics was fixed at a depth of 22 ft in Borehole C4993, and a 3-D geophone from the University of Texas (UT) was embedded near the borehole at about 1.5 ft below the ground surface. The Redpath geophone and the UT geophone were properly aligned so that one of the horizontal components in each geophone was aligned with the direction of horizontal shaking of the T-Rex base plate. This volume is organized into 12 sections as follows. Section 1: Introduction, Section 2: Explanation of Terminology, Section 3: Vs Profile at Borehole C4993

  9. Effect of postural changes on 3D joint angular velocity during starting block phase.

    PubMed

    Slawinski, Jean; Dumas, Raphaël; Cheze, Laurence; Ontanon, Guy; Miller, Christian; Mazure-Bonnefoy, Alice

    2013-01-01

    Few studies have focused on the effect of posture during sprint start. The aim of this study was to measure the effect of the modification of horizontal distance between the blocks during sprint start on three dimensional (3D) joint angular velocity. Nine trained sprinters started using three different starting positions (bunched, medium and elongated). They were equipped with 63 passive reflective markers, and an opto-electronic Motion Analysis system was used to collect the 3D marker trajectories. During the pushing phase on the blocks, norm of the joint angular velocity (NJAV), 3D Euler angular velocity (EAV) and pushing time on the blocks were calculated. The results demonstrated that the decrease of the block spacing induces an opposite effect on the angular velocity of joints of the lower and the upper limbs. The NJAV of the upper limbs is greater in the bunched start, whereas the NJAV of the lower limbs is smaller. The modifications of NJAV were due to a combination of the movement of the joints in the different degrees of freedom. The medium start seems to be the best compromise because it leads, in a short pushing time, to a combination of optimal joint velocities for upper and lower segments.

  10. Separate Perceptual and Neural Processing of Velocity- and Disparity-Based 3D Motion Signals.

    PubMed

    Joo, Sung Jun; Czuba, Thaddeus B; Cormack, Lawrence K; Huk, Alexander C

    2016-10-19

    Although the visual system uses both velocity- and disparity-based binocular information for computing 3D motion, it is unknown whether (and how) these two signals interact. We found that these two binocular signals are processed distinctly at the levels of both cortical activity in human MT and perception. In human MT, adaptation to both velocity-based and disparity-based 3D motions demonstrated direction-selective neuroimaging responses. However, when adaptation to one cue was probed using the other cue, there was no evidence of interaction between them (i.e., there was no "cross-cue" adaptation). Analogous psychophysical measurements yielded correspondingly weak cross-cue motion aftereffects (MAEs) in the face of very strong within-cue adaptation. In a direct test of perceptual independence, adapting to opposite 3D directions generated by different binocular cues resulted in simultaneous, superimposed, opposite-direction MAEs. These findings suggest that velocity- and disparity-based 3D motion signals may both flow through area MT but constitute distinct signals and pathways.

  11. The terminal velocity of volcanic particles with shape obtained from 3D X-ray microtomography

    NASA Astrophysics Data System (ADS)

    Dioguardi, Fabio; Mele, Daniela; Dellino, Pierfrancesco; Dürig, Tobias

    2017-01-01

    New experiments of falling volcanic particles were performed in order to define terminal velocity models applicable in a wide range of Reynolds number Re. Experiments were carried out with fluids of various viscosities and with particles that cover a wide range of size, density and shape. Particle shape, which strongly influences fluid drag, was measured in 3D by High-resolution X-ray microtomography, by which sphericity Φ3D and fractal dimension D3D were obtained. They are easier to measure and less operator dependent than the 2D shape parameters used in previous papers. Drag laws that make use of the new 3D parameters were obtained by fitting particle data to the experiments, and single-equation terminal velocity models were derived. They work well both at high and low Re (3 × 10- 2 < Re < 104), while earlier formulations made use of different equations at different ranges of Re. The new drag laws are well suited for the modelling of particle transportation both in the eruptive column, where coarse and fine particles are present, and also in the distal part of the umbrella region, where fine ash is involved in the large-scale domains of atmospheric circulation. A table of the typical values of Φ3D and D3D of particles from known plinian, subplinian and ash plume eruptions is presented. Graphs of terminal velocity as a function of grain size are finally proposed as tools to help volcanologists and atmosphere scientists to model particle transportation of explosive eruptions.

  12. Validation of S-wave Velocity beneath the Ise Bay, Central Japan, Using Continuous Short-period Ambient Noise Data

    NASA Astrophysics Data System (ADS)

    Hayashida, T.; Yoshimi, M.; Horikawa, H.

    2014-12-01

    We have applied seismic interferometry to three-component ambient noise data recorded around the Ise bay area, central Japan, to validate published three-dimensional S-wave velocity models. For the bay area, detailed seismic velocity structure models have been constructed based on P-wave reflection surveys. There is no direct information on the S-wave velocities beneath the bay and the parameters are assigned by reference to those in a land area. We used one-year continuous data from 20 permanent stations of the NIED Hi-net (High-sensitivity seismograph network) to obtain stacked cross-correlation functions (CCFs) of ambient noise between station pairs that cross the bay. The CCFs were calculated, using one-hour data in the radial-radial (R-R), transverse-transverse (T-T) and vertical-vertical (Z-Z) directions for time lags of ±500s. Horizontal distances between the stations range form 15 km to 103 km. Although the Hi-net stations deploy seismometers with the natural period of 1 s, we found that the yearly stacked CCFs for selected 101 Hi-net station pairs are comparable with those derived from neighboring broadband seismic stations in the frequency range between 0.1 and 0.5 Hz, by deconvolving the instrument response. The CCFs shows clear Rayleigh waves from all directions in the R-R and Z-Z components, and clear Love waves in the T-T component with reasonable signal-to-noise ratios. The derived group velocities and waveforms of the wave trains are variable in the higher frequency range (> 0.2 Hz), indicating deep sedimentary basin beneath the bay. We compared obtained group velocities with theoretical ones to find systematic differences between the expected structure model from the CCFs and the published models in the northwest part of the bay, while the agreements are generally good for many other station pairs. This result indicates that the seismic interferometry technique provides valuable information for validation and improvement of a velocity structure

  13. Stratified shear flow in an inclined duct: near-instantaneous 3D velocity and density measurements

    NASA Astrophysics Data System (ADS)

    Partridge, Jamie; Lefauve, Adrien; Dalziel, Stuart; Linden, Paul

    2016-11-01

    We present results from a new experimental setup to study the exchange flow in an inclined square duct between two reservoirs containing fluids of different densities. This system can exhibit stratified shear wave motions, and has a distinct parameter threshold above which turbulence is triggered and progressively fills a larger fraction of the duct. To probe these intrinsically 3D flows, we introduce a new setup in which a traversing laser sheet allows us to obtain near-instantaneous 3D velocity and density fields. Three components of velocity are measured on successive 2D planes using stereo particle image velocimetry (PIV) with density information obtained simultaneously using laser induced fluorescence (LIF). Supported by EPSRC Programme Grant EP/K034529/1 entitled "Mathematical Underpinnings of Stratified Turbulence".

  14. Analysis of the 3D Structure and Velocity of a CME on 2 January 2008

    NASA Astrophysics Data System (ADS)

    López, F. M.; Cremades, H.

    We perform an analysis of the 3D structure and velocity of a CME (coronal mass ejection) ejected on 2 January 2008. The event was imaged by both STEREO A and B spacecraft (mutual separation of ˜44°), providing polarized images of the event from two different points of view. To obtain information on the 3D structure of the CME from polarized images, a polarization technique (Moran & Davila, Science 305, 66, 2003) is applied. Aided by this method, we have constructed topographical maps which show the height of the various event features from the plane of the sky (i.e. toward or away from the observer) and have dinamically analyzed and compared the real and projected on the plane of the sky velocities.

  15. S-wave velocity structure and tectonic implications of the northwestern sub-basin and Macclesfield of the South China Sea

    NASA Astrophysics Data System (ADS)

    Wei, Xiaodong; Ruan, Aiguo; Li, Jiabiao; Niu, Xiongwei; Wu, Zhenli; Ding, Weiwei

    2016-10-01

    Based on the optimum P-wave model, the S-wave velocity structure of a wide angle seismic profile (OBS2006-1), across the northwestern sub-basin (NWSB) and the Macclesfield, is simulated by a 2-D ray-tracing method. The results indicate the S-wave velocities in the upper and lower crust of the NWSB are 3.2-3.6 km/s and 3.6-4.0 km/s, with Vp/Vs ratios of 1.82-1.88 and 1.74-1.82, respectively, which reflect typical oceanic crust characteristics. The S-wave velocity in the upper crust of the NWSB is a little higher in the NNW segment than that in the SSE segment, while the lateral variation of Vp/Vs ratio is in the opposite. We suggest that the NWSB might have experienced asymmetrical magma flows during sea floor spreading, which may have blurred the magnetic anomaly lineation. The comparison of S-wave velocities along the northern margin of the SCS shows that the west section is different from the east section, and the northwestern margin has a non-volcanic crust structure. The S-wave structures and P-wave velocity models along the northern margin, Macclesfield and Reed Bank show that the Macclesfield might have a conjugate relationship with the Reed Bank.

  16. Borehole P- and S-wave velocity at thirteen stations in Southern California

    USGS Publications Warehouse

    Gibbs, James F.; Boore, David M.; Tinsley, John C.; Mueller, Charles S.

    2001-01-01

    The U.S. Geological Survey (USGS), as part of a program to acquire seismic velocity data at locations of strong-ground motion in earthquakes (e.g., Gibbs et al., 2000), has investigated thirteen additional sites in the Southern California region. Of the thirteen sites, twelve are in the vicinity of Whittier, California, and one is located in San Bernardino, California. Several deployments of temporary seismographs were made after the Whittier Narrows, California earthquake of 1 October 1987 (Mueller et al., 1988). A deployment, between 2 October and 9 November 1987, was the motivation for selection of six of the drill sites. Temporary portable seismographs at Hoover School (HOO), Lincoln School (LIN), Corps of Engineers Station (NAR), Olive Junior High School (OLV), Santa Anita Golf Course (SAG), and Southwestern Academy (SWA) recorded significant aftershock data. These portable sites, with the exception of Santa Anita Golf Course, were co-sited with strong-motion recorders. Stations at HOO, Lincoln School Whittier (WLB), Saint Paul High School (STP), Alisos Adult School (EXC), Cerritos College Gymnasium (CGM), Cerritos College Physical Science Building (CPS), and Cerritos College Police Building (CPB) were part of an array of digital strong-motion stations deployed from "bedrock" in Whittier to near the deepest part of the Los Angeles basin in Norwalk. Although development and siting of this new array (partially installed at the time of this writing) was generally motivated by the Whittier Narrows earthquake, these new sites (with the exception of HOO) were not part of any Whittier Narrows aftershock deployments. A similar new digital strong-motion site was installed at the San Bernardino Fire Station during the same time frame. Velocity data were obtained to depths of about 90 meters at two sites, 30 meters at seven sites, and 18 to 25 meters at four sites. Lithology data from the analysis of cuttings and samples was obtained from the two 90-meter deep holes and

  17. A 3D radiative transfer framework . VII. Arbitrary velocity fields in the Eulerian frame

    NASA Astrophysics Data System (ADS)

    Seelmann, A. M.; Hauschildt, P. H.; Baron, E.

    2010-11-01

    Aims: A solution of the radiative-transfer problem in 3D with arbitrary velocity fields in the Eulerian frame is presented. The method is implemented in our 3D radiative transfer framework and used in the PHOENIX/3D code. It is tested by comparison to our well-tested 1D co-moving frame radiative transfer code, where the treatment of a monotonic velocity field is implemented in the Lagrangian frame. The Eulerian formulation does not need much additional memory and is useable on state-of-the-art computers, even large-scale applications with 1000's of wavelength points are feasible. Methods: In the Eulerian formulation of the problem, the photon is seen by the atom at a Doppler-shifted wavelength depending on its propagation direction, which leads to a Doppler-shifted absorption and emission. This leads to a different source function and a different Λ^* operator in the radiative transfer equations compared to the static case. Results: The results of the Eulerian 3D spherical calculations are compared to our well-tested 1D Lagrangian spherical calculations, the agreement is, up to vmax = 1 × 103 km s-1 very good. Test calculation in other geometries are also shown.

  18. Locating earthquakes in west Texas oil fields using 3-D anisotropic velocity models

    SciTech Connect

    Hua, Fa; Doser, D.; Baker, M. . Dept. of Geological Sciences)

    1993-02-01

    Earthquakes within the War-Wink gas field, Ward County, Texas, that have been located with a 1-D velocity model occur near the edges and top of a naturally occurring overpressured zone. Because the War-Wink field is a structurally controlled anticline with significant velocity anisotropy associated with the overpressured zone and finely layered evaporites, the authors have attempted to re-locate earthquakes using a 3-D anisotropic velocity model. Preliminary results with this model give the unsatisfactory result that many earthquakes previously located at the top of the overpressured zone (3-3.5 km) moved into the evaporites (1-1.5 km) above the field. They believe that this result could be caused by: (1) aliasing the velocity model; or (2) problems in determining the correct location minima when several minima exist. They are currently attempting to determine which of these causes is more likely for the unsatisfactory result observed.

  19. High frequency measurement of P- and S-wave velocities on crystalline rock massif surface - methodology of measurement

    NASA Astrophysics Data System (ADS)

    Vilhelm, Jan; Slavík, Lubomír

    2014-05-01

    For the purpose of non-destructive monitoring of rock properties in the underground excavation it is possible to perform repeated high-accuracy P- and S-wave velocity measurements. This contribution deals with preliminary results gained during the preparation of micro-seismic long-term monitoring system. The field velocity measurements were made by pulse-transmission technique directly on the rock outcrop (granite) in Bedrichov gallery (northern Bohemia). The gallery at the experimental site was excavated using TBM (Tunnel Boring Machine) and it is used for drinking water supply, which is conveyed in a pipe. The stable measuring system and its automatic operation lead to the use of piezoceramic transducers both as a seismic source and as a receiver. The length of measuring base at gallery wall was from 0.5 to 3 meters. Different transducer coupling possibilities were tested namely with regard of repeatability of velocity determination. The arrangement of measuring system on the surface of the rock massif causes better sensitivity of S-transducers for P-wave measurement compared with the P-transducers. Similarly P-transducers were found more suitable for S-wave velocity determination then P-transducers. The frequency dependent attenuation of fresh rock massif results in limited frequency content of registered seismic signals. It was found that at the distance between the seismic source and receiver from 0.5 m the frequency components above 40 kHz are significantly attenuated. Therefore for the excitation of seismic wave 100 kHz transducers are most suitable. The limited frequency range should be also taken into account for the shape of electric impulse used for exciting of piezoceramic transducer. The spike pulse generates broad-band seismic signal, short in the time domain. However its energy after low-pass filtration in the rock is significantly lower than the energy of seismic signal generated by square wave pulse. Acknowledgments: This work was partially

  20. S-wave velocity as an indicator of solid-liquid transition in clay

    NASA Astrophysics Data System (ADS)

    Mainsant, Guénolé; Jongmans, Denis; Chambon, Guillaume; Larose, Eric; Baillet, Laurent

    2013-04-01

    Clayey landslides, which are widely spread all over the world, pose specific problems to territorial planners, owing to dramatic variations in kinematics. Indeed, the analysis of landslide movements in a clay-rich area like the Trièves plateau (French Western Alps) indicates that slow slope movements can suddenly accelerate or fluidize as a result of heavy and/or long-lasting rainfalls or loading. Previous rheometric tests performed on the Trièves clay revealed a thixotropic behavior of the clay with a highly pronounced viscosity bifurcation at a yield stress τc. Below that stress, the material behaves like a solid, while it abruptly starts flowing when this yield stress is reached. This solid-liquid transition was investigated by measuring the variations of the shear wave velocity (Vs) in the Trièves clay during rheometric tests and flume tests. First, rheometric parallel-plate tests were performed at 3 different clay water contents (52%, 66% and 78%). Oscillatory stress tests were conducted during the experiments, allowing the shear modulus and Vs to be measured as a function of the shear stress level. Results revealed a dramatic Vs change at the same yield stress as for the viscosity bifurcation. When the stress is lower than the yield stress, Vs regularly increases with time up to a limit value. As soon as the yield stress is reached, Vs abruptly decreases to reach values of a few m/s in the fluidized clay. In order to investigate at a larger scale (approximately 1 m) the evolution of the shear wave velocity during the clay fluidization, flume tests were performed for two clay water contents (57 % and 68%). These experiments consist in progressively tilting a flume filled with a saturated clay layer (35cm wide, 60cm long and 10cm deep) until reaching the fluidization at a given slope. The Rayleigh wave velocity (VR), which is related to Vs, was continuously monitored using a piezometric source and 4 vertical component accelerometers placed at the surface of

  1. Validation of 3D Seismic Velocity Models Using the Spectral Element Method

    NASA Astrophysics Data System (ADS)

    Maceira, M.; Larmat, C. S.; Porritt, R. W.; Higdon, D.; Allen, R. M.

    2012-12-01

    For over a decade now, many research institutions have been focusing on addressing the Earth's 3D heterogeneities and complexities by improving tomographic methods. Utilizing dense array datasets, these efforts have led to unprecedented 3D seismic images, but little is done in terms of model validation or to provide any absolute assessment of model uncertainty. Furthermore, the question of "How good is a 3D geophysical model at representing the Earth's true physics? " remains largely not addressed in a time when 3D Earth models are used for societal and energy security. In the last few years, new horizons have opened up in earth structure imaging, with the advent of new numerical and mathematical methods in computational seismology and statistical sciences. We use these methods to tackle the question of model validation taking advantage of unique and extensive High Performance Computing resources available at Los Alamos National Laboratory. We present results from a study focused on validating 3D models for the Western USA generated using both ray-theoretical and finite-frequency approximations. In this manner we do not validate just the model but also the imaging technique. For this test case, we utilize the Dynamic North America (DNA) model family of UC Berkeley, as they are readily available in both formulations. We evaluate model performances by comparing observed and synthetic seismograms generated using the Spectral Element Method. Results show that both, finite-frequency and ray-theoretical DNA09 models, predict the observations well. Waveform cross-correlation coefficients show a difference in performance between models obtained with the finite-frequency or ray-theory limited to smallest periods (<15s), with no perceptible difference at longer periods (50-200s). At those shortest periods, and based on statistical analyses on S-wave phase delay measurements, finite-frequency shows an improvement over ray theory. We are also investigating the breakdown of ray

  2. UCVM: An Open Source Framework for 3D Velocity Model Research

    NASA Astrophysics Data System (ADS)

    Gill, D.; Maechling, P. J.; Jordan, T. H.; Plesch, A.; Taborda, R.; Callaghan, S.; Small, P.

    2013-12-01

    Three-dimensional (3D) seismic velocity models provide fundamental input data to ground motion simulations, in the form of structured or unstructured meshes or grids. Numerous models are available for California, as well as for other parts of the United States and Europe, but models do not share a common interface. Being able to interact with these models in a standardized way is critical in order to configure and run 3D ground motion simulations. The Unified Community Velocity Model (UCVM) software, developed by researchers at the Southern California Earthquake Center (SCEC), is an open source framework designed to provide a cohesive way to interact with seismic velocity models. We describe the several ways in which we have improved the UCVM software over the last year. We have simplified the UCVM installation process by automating the installation of various community codebases, improving the ease of use.. We discuss how UCVM software was used to build velocity meshes for high-frequency (4Hz) deterministic 3D wave propagation simulations, and how the UCVM framework interacts with other open source resources, such as NetCDF file formats for visualization. The UCVM software uses a layered software architecture that transparently converts geographic coordinates to the coordinate systems used by the underlying velocity models and supports inclusion of a configurable near-surface geotechnical layer, while interacting with the velocity model codes through their existing software interfaces. No changes to the velocity model codes are required. Our recent UCVM installation improvements bundle UCVM with a setup script, written in Python, which guides users through the process that installs the UCVM software along with all the user-selectable velocity models. Each velocity model is converted into a standardized (configure, make, make install) format that is easily downloaded and installed via the script. UCVM is often run in specialized high performance computing (HPC

  3. 3D P-wave Velocity Structure Beneath the Eastern Canadian Shield and Northern Appalachian Region

    NASA Astrophysics Data System (ADS)

    Villemaire, M.; Darbyshire, F. A.; Bastow, I. D.

    2010-12-01

    Previous seismic studies of the upper mantle of the Canadian Shield have indicated some low-velocity anomalies within the cratonic lithosphere in the Abitibi-Grenville region. The lack of seismograph station coverage to the east and south-east of the studied area prevented definition of the 3D geometry of these anomalies. Adding new stations from the province of Quebec and from the northeastern United States allows us to carry out new studies of the P-wave velocity structure of the upper mantle, in order to better understand the complexity of the region and the interaction of the lithosphere with possible thermal anomalies in the underlying mantle. We analysed teleseismic P wave arrivals from almost 200 earthquakes, recorded at 45 stations deployed across the provinces of Quebec and Ontario and across the northeastern US. The relative arrival times of teleseismic P waves across the array were measured using the cross-correlation method of VanDecar & Crosson (1990). The travel time data were then inverted to estimate the 3D P-wave velocity structure beneath the region, using the least-squares tomographic inversion code of VanDecar (1991). The model shows some interesting features. We see a diffuse low-velocity structure beneath New-England that extends to at least 500 km depth, and that may be related to the Appalachian Mountain belt. There is also a linear low-velocity structure, flanked by higher velocities, perpendicular to the Grenville Front, and along the Ottawa Valley. We interpret this feature as a mantle signature of the Great Meteor Hotspot track. We have looked for systematic differences between the mantle underlying the Archean Superior craton and the Proterozoic Grenville Province but did not find a significant difference in the upper mantle. We investigate the role of thermal and compositional effects to interpret the velocity models and to relate the patterns of the anomalies to past and present tectonic structures.

  4. 3D seismic velocity structure in the rupture area of the 2014 M8.2 Iquique earthquake in Northern Chile

    NASA Astrophysics Data System (ADS)

    Woollam, Jack; Fuenzallida, Amaya; Garth, Tom; Rietbrock, Andreas; Ruiz, Sergio; Tavera, Hernando

    2016-04-01

    Seismic velocity tomography is one of the key tools in Earth sciences to image the physical properties of the subsurface. In recent years significant advances have been made to image the Chilean subductions zone, especially in the area of the 2010 M8.8 Maule earthquake (e.g. Hicks et al., 2014), providing much needed physical constraints for earthquakes source inversions and rupture models. In 2014 the M8.2 Iquique earthquake struck the northern part of the Chilean subduction zone in close proximity to the Peruvian boarder. The pre- and aftershock sequence of this major earthquake was recorded by a densified seismological network in Northern Chile and Southern Peru, which provides an excellent data set to study in depth the 3D velocity structure along the subduction megathrust. Based on an automatic event catalogue of nearly 10,000 events spanning the time period March to May 2014 we selected approximately 450 events for a staggered 3D inversion approach. Events are selected to guarantee an even ray coverage through the inversion volume. We only select events with a minimum GAP of 200 to improve depth estimates and therefore increase resolution in the marine forearc. Additionally, we investigate secondary arrivals between the P- and S-wave arrival to improve depth location. Up to now we have processed about 450 events, from which about 150 with at least 30 P- and S-wave observations have been selected for the subsequent 3D tomography. Overall the data quality is very high, which allows arrival time estimates better than 0.05s on average. We will show results from the 1D, 2D, and preliminary 3D inversions and discuss the results together with the obtained seismicity distribution.

  5. Ultrasonic 3-D Vector Flow Method for Quantitative In Vivo Peak Velocity and Flow Rate Estimation.

    PubMed

    Holbek, Simon; Ewertsen, Caroline; Bouzari, Hamed; Pihl, Michael Johannes; Hansen, Kristoffer Lindskov; Stuart, Matthias Bo; Thomsen, Carsten; Nielsen, Michael Bachmann; Jensen, Jorgen Arendt

    2017-03-01

    Current clinical ultrasound (US) systems are limited to show blood flow movement in either 1-D or 2-D. In this paper, a method for estimating 3-D vector velocities in a plane using the transverse oscillation method, a 32×32 element matrix array, and the experimental US scanner SARUS is presented. The aim of this paper is to estimate precise flow rates and peak velocities derived from 3-D vector flow estimates. The emission sequence provides 3-D vector flow estimates at up to 1.145 frames/s in a plane, and was used to estimate 3-D vector flow in a cross-sectional image plane. The method is validated in two phantom studies, where flow rates are measured in a flow-rig, providing a constant parabolic flow, and in a straight-vessel phantom ( ∅=8 mm) connected to a flow pump capable of generating time varying waveforms. Flow rates are estimated to be 82.1 ± 2.8 L/min in the flow-rig compared with the expected 79.8 L/min, and to 2.68 ± 0.04 mL/stroke in the pulsating environment compared with the expected 2.57 ± 0.08 mL/stroke. Flow rates estimated in the common carotid artery of a healthy volunteer are compared with magnetic resonance imaging (MRI) measured flow rates using a 1-D through-plane velocity sequence. Mean flow rates were 333 ± 31 mL/min for the presented method and 346 ± 2 mL/min for the MRI measurements.

  6. High-resolution P and S-wave Velocity Structures from Elastic Full Waveform Inversion of Multi-Component Ocean Bottom Cable Seismic Data

    NASA Astrophysics Data System (ADS)

    Sears, T.; Singh, S. C.; Barton, P.

    2007-12-01

    Full waveform inversion is becoming a realistic option with the advent of modern computing facilities, both in global and exploration seismology. Over the last ten years, we have developed a series of elastic full waveform inversion algorithm and have applied to a variety of acquisition geometry. The forward modelling is based on the finite difference approximation to the full elastic wave equation in the time domain, which can incorporate converted waves, refraction, and attenuation. The inversion algorithm is based on the minimisation of observed data with synthetic data in a least-squares sense, and requires a cross-correlation of the back propagation of residual with forward propagated wavefield in a background media. Starting with the background velocity obtained using travel time inversion, we first invert wide-angle and low frequency data, which provides medium wavelength velocity structure, and then invert near offset and high frequencies that leads to high-resolution P- and S-wave velocity structure. We first invert vertical component data to obtain short wavelength P- and S-wave velocities, which are constrained by amplitude versus offset behaviour of the P-P reflection, and then invert horizontal component data to obtain very-high resolution S-wave velocity structure, which is constrained by P-S reflection. Finally, we invert all the data simultaneously to have consistency over the data and model space. We found that the high-resolution S-wave velocity image is far superior than the P-wave velocity image and provides information that may not be present in the P-wave velocity image. Combined P and S-wave velocity structure could be used to quantify sub-surface lithology and fluid saturation and pressure. In this presentation we will highlight the challenges faced during the development of our waveform inversion and their implication for the global seismology problems.

  7. Estimation of shallow S-wave velocity structure and site response characteristics by microtremor array measurements in Tekirdag region, NW Turkey

    NASA Astrophysics Data System (ADS)

    Karagoz, Ozlem; Chimoto, Kosuke; Citak, Seckin; Ozel, Oguz; Yamanaka, Hiroaki; Hatayama, Ken

    2015-11-01

    In this study, we aimed to explore the S-wave velocity structure of shallow soils using microtremors in order to estimate site responses in Tekirdag and surrounding areas (NW Turkey). We collected microtremor array data at 44 sites in Tekirdag, Marmara Ereglisi, Corlu, and Muratlı. The phase velocities of Rayleigh waves were estimated from the microtremor data using a Spatial Autocorrelation method. Then, we applied a hybrid genetic simulated annealing algorithm to obtain a 1D S-wave velocity structure at each site. Comparison between the horizontal-to-vertical ratio of microtremors and computed ellipticities of the fundamental mode Rayleigh waves showed good agreement with validation models. The depth of the engineering bedrock changed from 20 to 50 m in the Tekirdag city center and along the coastline with a velocity range of 700-930 m/s, and it ranged between 10 and 65 m in Marmara Ereglisi. The average S-wave velocity of the engineering bedrock was 780 m/s in the region. We obtained average S-wave velocities in the upper 30 m to compare site amplifications. Empirical relationships between the AVs30, the site amplifications, and also average topographic slopes were established for use in future site effects microzonation studies in the region.

  8. Using twelve years of USGS refraction lines to calibrate the Brocher and others (1997) 3D velocity model of the Bay Area

    USGS Publications Warehouse

    Boatwright, John; Blair, Luke; Catchings, Rufus; Goldman, Mark; Perosi, Fabio; Steedman, Clare

    2004-01-01

    Campbell (1983) demonstrated that site amplification correlates with depths to the 1.0, 1.5, and 2.5 km/s S-wave velocity horizons. To estimate these depths for the Bay Area stations in the PEER/NGA database, we compare the depths to the 3.2 and 4.4 km/s P-wave velocities in the Brocher and others (1997) 3D velocity model with the depths to these horizons determined from 6 refraction lines shot in the Bay Area from 1991 to 2003. These refraction lines range from two recent 20 km lines that extend from Los Gatos to downtown San Jose, and from downtown San Jose into Alum Rock Park, to two older 200 km lines than run axially from Hollister up the San Francisco Peninsula to Inverness and from Hollister up the East Bay across San Pablo Bay to Santa Rosa. Comparison of these cross-sections with the Brocher and others (1997) model indicates that the 1.5 km/s S-wave horizon, which we correlate with the 3.2 km/s P-wave horizon, is the most reliable horizon that can be extracted from the Brocher and others (1997) velocity model. We determine simple adjustments to bring the Brocher and others (1997) 3.2 and 4.4 km/s P-wave horizons into an average agreement with the refraction results. Then we apply these adjustments to estimate depths to the 1.5 and 2.5 km/s S-wave horizons beneath the strong motion stations in the PEER/NGA database.

  9. Direct ambient noise tomography for 3-D near surface shear velocity structure: methodology and applications

    NASA Astrophysics Data System (ADS)

    Yao, H.; Fang, H.; Li, C.; Liu, Y.; Zhang, H.; van der Hilst, R. D.; Huang, Y. C.

    2014-12-01

    Ambient noise tomography has provided essential constraints on crustal and uppermost mantle shear velocity structure in global seismology. Recent studies demonstrate that high frequency (e.g., ~ 1 Hz) surface waves between receivers at short distances can be successfully retrieved from ambient noise cross-correlation and then be used for imaging near surface or shallow crustal shear velocity structures. This approach provides important information for strong ground motion prediction in seismically active area and overburden structure characterization in oil and gas fields. Here we propose a new tomographic method to invert all surface wave dispersion data for 3-D variations of shear wavespeed without the intermediate step of phase or group velocity maps.The method uses frequency-dependent propagation paths and a wavelet-based sparsity-constrained tomographic inversion. A fast marching method is used to compute, at each period, surface wave traveltimes and ray paths between sources and receivers. This avoids the assumption of great-circle propagation that is used in most surface wave tomographic studies, but which is not appropriate in complex media. The wavelet coefficients of the velocity model are estimated with an iteratively reweighted least squares (IRLS) algorithm, and upon iterations the surface wave ray paths and the data sensitivity matrix are updated from the newly obtained velocity model. We apply this new method to determine the 3-D near surface wavespeed variations in the Taipei basin of Taiwan, Hefei urban area and a shale and gas production field in China using the high-frequency interstation Rayleigh wave dispersion data extracted from ambient noisecross-correlation. The results reveal strong effects of off-great-circle propagation of high-frequency surface waves in these regions with above 30% shear wavespeed variations. The proposed approach is more efficient and robust than the traditional two-step surface wave tomography for imaging complex

  10. Intraplate Basaltic Volcanism in the Basin and Range, USA: Relationship to Low-Velocity S- wave Anomalies and Asthenospheric Dynamics

    NASA Astrophysics Data System (ADS)

    Tibbetts, A. K.; Smith, E. I.; Conrad, C.; Lee, C.; Plank, T.; Yang, Y.

    2009-05-01

    Pliocene to Recent intraplate mafic volcanic rocks of the Basin and Range Province mostly formed by asthenospheric melting, as can be seen by melting temperatures. Here asthenosphere is defined by mantle rheology and temperature and not by geochemistry. The duration of melting in a volcanic field may be related to the size and shape of pockets of low velocity asthenosphere moving under the areas of volcanism. Seismic S- wave velocity profiles constrained by ambient noise and earthquake tomography of the mantle (Yang et al., 2008) show low velocity pockets, which may correspond to higher temperatures and/or higher water contents. By applying an asthenospheric flow velocity of 5 cm/yr east (Silver and Holt 2002, Conrad et al., 2007), the distance the mantle has moved since the time of volcanism can be calculated for basalts of known age. Past positions of low-velocity anomalies in the asthenosphere combined with depths and temperatures of melting calculated using the silica-liquid geobarometer (Lee et al., 2009) were used to determine if a low velocity anomaly existed under an area of volcanism at the depth of melting and time of eruption. The data constraints used for calculating depths and temperatures of melting are dry, MgO > 7.5 wt. %, SiO2 > 44 wt.%, and Fe as 90% Fe2+. Depths and temperatures of melting were calculated for several basalt fields of known age. Ages, temperatures, and depths are as follows: Death Valley 4 Ma, 1295-1350°C, and 42-63 km; Crater Flat 80 ka, 1 Ma, 3.8 Ma, 1388-1415°C, and 80-90 km; Lunar Crater 2.9-5.7 Ma, 1414-1480°C, and 80-121 km; Reveille 3.8-4.6 Ma, 1458-1516°C, and 110-140 km; Coso 0.23-5.3 Ma, 1244-1399°C, and 39.6-72 km; Big Pine 0.9-1.8 Ma, 1276-1356°C, and 42-72 km; Long Valley 0.4-3.2 Ma, 1289- 1323°C, and 44-50 km; Cima 0.3-8.3 Ma, 1330-1376°C, and 53-82 km; Snow Canyon <10,000 years, 1470-1485°C, and 75-85 km. Ages were converted to km of mantle motion and to degrees of longitude and plotted on seismic profiles

  11. Comparative velocity structure of active Hawaiian volcanoes from 3-D onshore-offshore seismic tomography

    USGS Publications Warehouse

    Park, J.; Morgan, J.K.; Zelt, C.A.; Okubo, P.G.; Peters, L.; Benesh, N.

    2007-01-01

    We present a 3-D P-wave velocity model of the combined subaerial and submarine portions of the southeastern part of the Island of Hawaii, based on first-arrival seismic tomography of marine airgun shots recorded by the onland seismic network. Our model shows that high-velocity materials (6.5-7.0??km/s) lie beneath Kilauea's summit, Koae fault zone, and the upper Southwest Rift Zone (SWRZ) and upper and middle East Rift Zone (ERZ), indicative of magma cumulates within the volcanic edifice. A separate high-velocity body of 6.5-6.9??km/s within Kilauea's lower ERZ and upper Puna Ridge suggests a distinct body of magma cumulates, possibly connected to the summit magma cumulates at depth. The two cumulate bodies within Kilauea's ERZ may have undergone separate ductile flow seaward, influencing the submarine morphology of Kilauea's south flank. Low velocities (5.0-6.3??km/s) seaward of Kilauea's Hilina fault zone, and along Mauna Loa's seaward facing Kao'iki fault zone, are attributed to thick piles of volcaniclastic sediments deposited on the submarine flanks. Loihi seamount shows high-velocity anomalies beneath the summit and along the rift zones, similar to the interpreted magma cumulates below Mauna Loa and Kilauea volcanoes, and a low-velocity anomaly beneath the oceanic crust, probably indicative of melt within the upper mantle. Around Kilauea's submarine flank, a high-velocity anomaly beneath the outer bench suggests the presence of an ancient seamount that may obstruct outward spreading of the flank. Mauna Loa's southeast flank is also marked by a large, anomalously high-velocity feature (7.0-7.4??km/s), interpreted to define an inactive, buried volcanic rift zone, which might provide a new explanation for the westward migration of Mauna Loa's current SWRZ and the growth of Kilauea's SWRZ. ?? 2007 Elsevier B.V. All rights reserved.

  12. Model-based correction of velocity measurements in navigated 3-D ultrasound imaging during neurosurgical interventions.

    PubMed

    Iversen, Daniel Hoyer; Lindseth, Frank; Unsgaard, Geirmund; Torp, Hans; Lovstakken, Lasse

    2013-09-01

    In neurosurgery, information of blood flow is important to identify and avoid damage to important vessels. Three-dimensional intraoperative ultrasound color-Doppler imaging has proven useful in this respect. However, due to Doppler angle-dependencies and the complexity of the vascular architecture, clinical valuable 3-D information of flow direction and velocity is currently not available. In this work, we aim to correct for angle-dependencies in 3-D flow images based on a geometric model of the neurovascular tree generated on-the-fly from free-hand 2-D imaging and an accurate position sensor system. The 3-D vessel model acts as a priori information of vessel orientation used to angle-correct the Doppler measurements, as well as provide an estimate of the average flow direction. Based on the flow direction we were also able to do aliasing correction to approximately double the measurable velocity range. In vitro experiments revealed a high accuracy and robustness for estimating the mean direction of flow. Accurate angle-correction of axial velocities were possible given a sufficient beam-to-flow angle for at least parts of a vessel segment . In vitro experiments showed an absolute relative bias of 9.5% for a challenging low-flow scenario. The method also showed promising results in vivo, improving the depiction of flow in the distal branches of intracranial aneurysms and the feeding arteries of an arteriovenous malformation. Careful inspection by an experienced surgeon confirmed the correct flow direction for all in vivo examples.

  13. Shallow P- and S-wave velocities and site resonances in the St. Louis region, Missouri-Illinois

    USGS Publications Warehouse

    Williams, R.A.; Odum, J.K.; Stephenson, W.J.; Herrmann, Robert B.

    2007-01-01

    As part of the seismic hazard-mapping efforts in the St. Louis metropolitan area we determined the compressional and shear-wave velocities (Vp and Vs) to about a 40-m depth at 17 locations in this area. The Vs measurements were made using high-resolution seismic refraction and reflection methods. We find a clear difference in the Vs profiles between sites located on the river floodplains and those located in the upland urban areas of St. Louis. Vs30 (average Vs to 30-m depth) values in floodplain areas range from 200 to 290 m/s (NEHRP category D) and contrast with sites on the upland areas of St. Louis, which have Vs30 values ranging from 410 to 785 m/s (NEHRP categories C and B). The lower Vs30 values and earthquake recordings in the floodplains suggest a greater potential for stronger and more prolonged ground shaking in an earthquake. Spectral analysis of a M3.6 earthquake recorded on the St. Louis-area ANSS seismograph network indicates stronger shaking and potentially damaging S-wave resonant frequencies at NEHRP category D sites compared to ground motions at a rock site located on the Saint Louis University campus. ?? 2007, Earthquake Engineering Research Institute.

  14. Simultaneous measurement of 3D zooplankton trajectories and surrounding fluid velocity field in complex flows.

    PubMed

    Adhikari, Deepak; Gemmell, Brad J; Hallberg, Michael P; Longmire, Ellen K; Buskey, Edward J

    2015-11-01

    We describe an automated, volumetric particle image velocimetry (PIV) and tracking method that measures time-resolved, 3D zooplankton trajectories and surrounding volumetric fluid velocity fields simultaneously and non-intrusively. The method is demonstrated for groups of copepods flowing past a wall-mounted cylinder. We show that copepods execute escape responses when subjected to a strain rate threshold upstream of a cylinder, but the same threshold range elicits no escape responses in the turbulent wake downstream. The method was also used to document the instantaneous slip velocity of zooplankton and the resulting differences in trajectory between zooplankton and non-inertial fluid particles in the unsteady wake flow, showing the method's capability to quantify drift for both passive and motile organisms in turbulent environments. Applications of the method extend to any group of organisms interacting with the surrounding fluid environment, where organism location, larger-scale eddies and smaller-scale fluid deformation rates can all be tracked and analyzed.

  15. A 3-D crustal velocity structure across the Variscides of southwest Ireland

    NASA Astrophysics Data System (ADS)

    Landes, M.; Readman, P. W.; O'Reilly, B. M.; Shannon, P. M.

    2003-04-01

    In the VARNET-96 experiment three seismic refraction profiles were acquired to examine the crustal structure in the south-west of Ireland. The shotpoint geometry allowed for both in-line and off-line fan shot recordings on the three profiles. Results of 3-D inversion modelling illustrate that there is pervasive lateral heterogeneity of the sedimentary and crustal velocity structure south of the Shannon Estuary. Palaeozoic strata at the south coast are about 5-6 km thick associated with the sedimentary infill of the Munster and South Munster Basins. To the north, shallow upper crust in the vicinity of the Killarney-Mallow Fault Zone is followed by a 3-4 km thick sedimentary succession in the Dingle-Shannon Basin. A zone of high-velocity upper crust (6.4-6.6 km/s) beneath the South Munster Basin correlates with a gravity high between the Kenmare-Killarney and the Leinster Granite gravity lows. Other high-velocity zones beneath Dingle Bay and the Kenmare River region may be associated with the deep traces of the Killarney-Mallow Fault Zone and the Cork-Kenmare Line. The 3-D velocity model was taken as a basis for the computation of PmP reflected arrivals from the crust-mantle boundary. The Moho depth varies from 28-29 km at the south coast to 32-33 km beneath the Dingle-Shannon Basin. Pervasive Variscan deformation appears to be confined to the sedimentary and upper crustal structure thus supporting a thin-skinned tectonic model for Variscan deformation. Deep-crustal variations only occur where they can be correlated with major tectonic features such as the Caledonian Iapetus Suture near the Shannon Estuary. The shallowing of the Moho towards the coast may result from Mesozoic crustal extension in the adjacent offshore sedimentary basins.

  16. GIA-Induced 3-D Crustal Velocities Predicted Using a New Generation of Viscoelastic Earth Models

    NASA Astrophysics Data System (ADS)

    Mitrovica, J. X.; Latychev, K.; Tamisiea, M. E.; Tromp, J.; Milne, G. A.

    2004-05-01

    In recent work we have described a new finite-volume, time-domain numerical scheme for predicting the response of a complex (Maxwell) viscoelastic Earth model to arbitrary surface mass loads. The method permits the incorporation of 3-D variations in mantle viscoelastic structure including, for example, heterogeneities in elastic plate strength and mantle viscosity. To address these complexities numerically, we have developed our code for a distributed (parallel) computer environment such as a Beowulf PC cluster. In this talk we apply the numerical formulation to compute a suite of predictions of present-day 3-D crustal deformation rates driven by the glacial isostatic adjustment process (GIA). These predictions are generated using an input global ice model and an ocean load computed using a solution to the governing `sea-level equation'. The latter is obtained in a numerical calculation that utilizes the same space-time discretization as in the main solver. Our goal is to assess the sensitivity of previous predictions of GIA-induced 3-D crustal rates based on spherically symmetric Earth models to the introduction of: (1) elastic plate thickness variations within oceanic regions and across the ocean-continent interface; and (2) variations in mantle viscosity inferred, indirectly, from a tomographic model of seismic velocity heterogeneity.

  17. Determination of Bedrock Variations and S-wave Velocity Structure in the NW part of Turkey for Earthquake Hazard Mitigation

    NASA Astrophysics Data System (ADS)

    Ozel, A. O.; Arslan, M. S.; Aksahin, B. B.; Genc, T.; Isseven, T.; Tuncer, M. K.

    2015-12-01

    Tekirdag region (NW Turkey) is quite close to the North Anatolian Fault which is capable of producing a large earthquake. Therefore, earthquake hazard mitigation studies are important for the urban areas close to the major faults. From this point of view, integration of different geophysical methods has important role for the study of seismic hazard problems including seismotectonic zoning. On the other hand, geological mapping and determining the subsurface structure, which is a key to assist management of new developed areas, conversion of current urban areas or assessment of urban geological hazards can be performed by integrated geophysical methods. This study has been performed in the frame of a national project, which is a complimentary project of the cooperative project between Turkey and Japan (JICA&JST), named as "Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education". With this principal aim, this study is focused on Tekirdag and its surrounding region (NW of Turkey) where some uncertainties in subsurface knowledge (maps of bedrock depth, thickness of quaternary sediments, basin geometry and seismic velocity structure,) need to be resolved. Several geophysical methods (microgravity, magnetic and single station and array microtremor measurements) are applied and the results are evaluated to characterize lithological changes in the region. Array microtremor measurements with several radiuses are taken in 30 locations and 1D-velocity structures of S-waves are determined by the inversion of phase velocities of surface waves, and the results of 1D structures are verified by theoretical Rayleigh wave modelling. Following the array measurements, single-station microtremor measurements are implemented at 75 locations to determine the predominant frequency distribution. The predominant frequencies in the region range from 0.5 Hz to 8 Hz in study area. On the other hand, microgravity and magnetic measurements are performed on

  18. Mapping refuse profile in Singapore old dumping ground through electrical resistivity, S-wave velocity and geotechnical monitoring.

    PubMed

    Yin, Ke; Tong, Huan Huan; Noh, Omar; Wang, Jing-Yuan; Giannis, Apostolos

    2015-03-01

    The purpose of this study was to track the refuse profile in Lorong Halus Dumping Ground, the largest landfill in Singapore, by electrical resistivity and surface wave velocity after 25 years of closure. Data were analyzed using an orthogonal set of plots by spreading 24 lines in two perpendicular geophone-orientation directions. Both geophysical techniques determined that refuse boundary depth was 13 ± 2 m. The refuse boundary revealed a certain degree of variance, mainly ascribed to the different principle of measurements, as well as the high heterogeneity of the subsurface. Discrepancy was higher in spots with greater heterogeneity. 3D analysis was further conducted detecting refuse pockets, leachate mounding and gas channels. Geotechnical monitoring (borehole) confirmed geophysical outcomes tracing different layers such as soil capping, decomposed refuse materials and inorganic wastes. Combining the geophysical methods with borehole monitoring, a comprehensive layout of the dumping site was presented showing the hot spots of interests.

  19. Imaging of 3-D seismic velocity structure of Southern Sumatra region using double difference tomographic method

    NASA Astrophysics Data System (ADS)

    Lestari, Titik; Nugraha, Andri Dian

    2015-04-01

    Southern Sumatra region has a high level of seismicity due to the influence of the subduction system, Sumatra fault, Mentawai fault and stretching zone activities. The seismic activities of Southern Sumatra region are recorded by Meteorological Climatological and Geophysical Agency (MCGA's) Seismograph network. In this study, we used earthquake data catalog compiled by MCGA for 3013 events from 10 seismic stations around Southern Sumatra region for time periods of April 2009 - April 2014 in order to invert for the 3-D seismic velocities structure (Vp, Vs, and Vp/Vs ratio). We applied double-difference seismic tomography method (tomoDD) to determine Vp, Vs and Vp/Vs ratio with hypocenter adjustment. For the inversion procedure, we started from the initial 1-D seismic velocity model of AK135 and constant Vp/Vs of 1.73. The synthetic travel time from source to receiver was calculated using ray pseudo-bending technique, while the main tomographic inversion was applied using LSQR method. The resolution model was evaluated using checkerboard test and Derivative Weigh Sum (DWS). Our preliminary results show low Vp and Vs anomalies region along Bukit Barisan which is may be associated with weak zone of Sumatran fault and migration of partial melted material. Low velocity anomalies at 30-50 km depth in the fore arc region may indicated the hydrous material circulation because the slab dehydration. We detected low seismic seismicity in the fore arc region that may be indicated as seismic gap. It is coincides contact zone of high and low velocity anomalies. And two large earthquakes (Jambi and Mentawai) also occurred at the contact of contrast velocity.

  20. Imaging of 3-D seismic velocity structure of Southern Sumatra region using double difference tomographic method

    SciTech Connect

    Lestari, Titik; Nugraha, Andri Dian

    2015-04-24

    Southern Sumatra region has a high level of seismicity due to the influence of the subduction system, Sumatra fault, Mentawai fault and stretching zone activities. The seismic activities of Southern Sumatra region are recorded by Meteorological Climatological and Geophysical Agency (MCGA’s) Seismograph network. In this study, we used earthquake data catalog compiled by MCGA for 3013 events from 10 seismic stations around Southern Sumatra region for time periods of April 2009 – April 2014 in order to invert for the 3-D seismic velocities structure (Vp, Vs, and Vp/Vs ratio). We applied double-difference seismic tomography method (tomoDD) to determine Vp, Vs and Vp/Vs ratio with hypocenter adjustment. For the inversion procedure, we started from the initial 1-D seismic velocity model of AK135 and constant Vp/Vs of 1.73. The synthetic travel time from source to receiver was calculated using ray pseudo-bending technique, while the main tomographic inversion was applied using LSQR method. The resolution model was evaluated using checkerboard test and Derivative Weigh Sum (DWS). Our preliminary results show low Vp and Vs anomalies region along Bukit Barisan which is may be associated with weak zone of Sumatran fault and migration of partial melted material. Low velocity anomalies at 30-50 km depth in the fore arc region may indicated the hydrous material circulation because the slab dehydration. We detected low seismic seismicity in the fore arc region that may be indicated as seismic gap. It is coincides contact zone of high and low velocity anomalies. And two large earthquakes (Jambi and Mentawai) also occurred at the contact of contrast velocity.

  1. Simultaneous inversion of 3D velocity structure, hypocenter locations, and reflector geometry in Cascadia

    NASA Astrophysics Data System (ADS)

    Preston, Leiph Alexander

    We develop and apply a non-linear inversion of direct and wide-angle reflection travel times for 3-D P-wave velocity structure, earthquake hypocenters, and reflector geometry under NW Washington focusing on the structure of the subducting Juan de Fuca plate. The first-arrival travel times are derived from both active-source experiments and from local earthquakes. The reflection arrivals were picked from data collected during the 1998 Wet SHIPS active-source experiment, which consisted of air-gun sources within the inland water-ways of NW Washington and SW British Columbia to land-based stations. Our inversion procedure reduces the well-known trade-off between reflector position and the velocities above it by the combination of simultaneous inversion and adequate crossing paths. We interpret the wide-angle reflector as the Moho of the subducting Juan de Fuca slab. The relocated intraslab earthquakes separate into two groups: those located up-dip of the 45km reflector depth contour generally lie below the reflector in material whose velocity exceeds 7.7km/s, placing them within the subducting mantle, while those down-dip of this contour occur within material whose velocities are 6.8--7.5km/s, placing them within subducted oceanic crust. We interpret these groups of earthquakes as resulting from serpentine dehydration in the subducted mantle and the basalt to eclogite transformation in the subducted crust. We have performed velocity checkerboard, slab velocity resolution, and parameter sensitivity tests to estimate our ability to resolve the relationship among the reflector, intraslab hypocenters, and slab velocity structure. These tests indicate we have the necessary resolvability and can distinguish the relative locations among the velocities, reflector, and intraslab hypocenters within the subducting slab to +/-2km. The occurrence of events within the subducted mantle geometrically allows for larger magnitude earthquakes than could occur if they were confined to

  2. The 3D Space and Spin Velocities of a Gamma-ray Pulsar

    NASA Astrophysics Data System (ADS)

    Romani, Roger W.

    2016-04-01

    PSR J2030+4415 is a LAT-discovered 0.5My-old gamma-ray pulsar with an X-ray synchrotron trail and a rare Halpha bowshock. We have obtained GMOS IFU spectroscopic imaging of this shell, and show a sweep through the remarkable Halpha structure, comparing with the high energy emission. These data provide a unique 3D map of the momentum distribution of the relativistic pulsar wind. This shows that the pulsar is moving nearly in the plane of the sky and that the pulsar wind has a polar component misaligned with the space velocity. The spin axis is shown to be inclined some 95degrees to the Earth line of sight, explaining why this is a radio-quiet, gamma-only pulsar. Intriguingly, the shell also shows multiple bubbles that suggest that the pulsar wind power has varied substantially over the past 500 years.

  3. P-Wave and S-Wave Velocity Structure of Submarine Landslide Associated With Gas Hydrate Layer on Frontal Ridge of Northern Cascadia Margin

    NASA Astrophysics Data System (ADS)

    He, T.; Lu, H.; Yelisetti, S.; Spence, G.

    2015-12-01

    The submarine landslide associated with gas hydrate is a potential risk for environment and engineering projects, and thus from long time ago it has been a hot topic of hydrate research. The study target is Slipstream submarine landslide, one of the slope failures observed on the frontal ridges of the Northern Cascadia accretionary margin off Vancouver Island. The previous studies indicated a possible connection between this submarine landslide feature and gas hydrate, whose occurrence is indicated by a prominent bottom-simulating reflector (BSR), at a depth of ~265-275 m beneath the seafloor (mbsf). The OBS (Ocean Bottom Seismometer) data collected during SeaJade (Seafloor Earthquake Array - Japan Canada Cascadia Experiment) project were used to derive the subseafloor velocity structure for both P- and S-wave using travel times picked from refraction and reflection events. The P-wave velocity structure above the BSR showed anomalous high velocities of about 2.0 km/s at shallow depths of 100 mbsf, closely matching the estimated depth of the glide plane (100 ± 10 m). Forward modelling of S-waves was carried out using the data from the OBS horizontal components. The S-wave velocities, interpreted in conjunction with the P-wave results, provide the key constraints on the gas hydrate distribution within the pores. The hydrate distribution in the pores is important for determining concentrations, and also for determining the frame strength which is critical for controlling slope stability of steep frontal ridges. The increase in S-wave velocity suggests that the hydrate is distributed as part of the load-bearing matrix to increase the rigidity of the sediment.

  4. Kinematic ground motion simulations on rough faults including effects of 3D stochastic velocity perturbations

    USGS Publications Warehouse

    Graves, Robert; Pitarka, Arben

    2016-01-01

    We describe a methodology for generating kinematic earthquake ruptures for use in 3D ground‐motion simulations over the 0–5 Hz frequency band. Our approach begins by specifying a spatially random slip distribution that has a roughly wavenumber‐squared fall‐off. Given a hypocenter, the rupture speed is specified to average about 75%–80% of the local shear wavespeed and the prescribed slip‐rate function has a Kostrov‐like shape with a fault‐averaged rise time that scales self‐similarly with the seismic moment. Both the rupture time and rise time include significant local perturbations across the fault surface specified by spatially random fields that are partially correlated with the underlying slip distribution. We represent velocity‐strengthening fault zones in the shallow (<5  km) and deep (>15  km) crust by decreasing rupture speed and increasing rise time in these regions. Additional refinements to this approach include the incorporation of geometric perturbations to the fault surface, 3D stochastic correlated perturbations to the P‐ and S‐wave velocity structure, and a damage zone surrounding the shallow fault surface characterized by a 30% reduction in seismic velocity. We demonstrate the approach using a suite of simulations for a hypothetical Mw 6.45 strike‐slip earthquake embedded in a generalized hard‐rock velocity structure. The simulation results are compared with the median predictions from the 2014 Next Generation Attenuation‐West2 Project ground‐motion prediction equations and show very good agreement over the frequency band 0.1–5 Hz for distances out to 25 km from the fault. Additionally, the newly added features act to reduce the coherency of the radiated higher frequency (f>1  Hz) ground motions, and homogenize radiation‐pattern effects in this same bandwidth, which move the simulations closer to the statistical characteristics of observed motions as illustrated by comparison with recordings from

  5. Using Adjoint Methods to Improve 3-D Velocity Models of Southern California

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Tape, C.; Maggi, A.; Tromp, J.

    2006-12-01

    We use adjoint methods popular in climate and ocean dynamics to calculate Fréchet derivatives for tomographic inversions in southern California. The Fréchet derivative of an objective function χ(m), where m denotes the Earth model, may be written in the generic form δχ=int Km(x) δln m(x) d3x, where δln m=δ m/m denotes the relative model perturbation. For illustrative purposes, we construct the 3-D finite-frequency banana-doughnut kernel Km, corresponding to the misfit of a single traveltime measurement, by simultaneously computing the 'adjoint' wave field s† forward in time and reconstructing the regular wave field s backward in time. The adjoint wave field is produced by using the time-reversed velocity at the receiver as a fictitious source, while the regular wave field is reconstructed on the fly by propagating the last frame of the wave field saved by a previous forward simulation backward in time. The approach is based upon the spectral-element method, and only two simulations are needed to produce density, shear-wave, and compressional-wave sensitivity kernels. This method is applied to the SCEC southern California velocity model. Various density, shear-wave, and compressional-wave sensitivity kernels are presented for different phases in the seismograms. We also generate 'event' kernels for Pnl, S and surface waves, which are the Fréchet kernels of misfit functions that measure the P, S or surface wave traveltime residuals at all the receivers simultaneously for one particular event. Effectively, an event kernel is a sum of weighted Fréchet kernels, with weights determined by the associated traveltime anomalies. By the nature of the 3-D simulation, every event kernel is also computed based upon just two simulations, i.e., its construction costs the same amount of computation time as an individual banana-doughnut kernel. One can think of the sum of the event kernels for all available earthquakes, called the 'misfit' kernel, as a graphical

  6. 3-D shear wave radially and azimuthally anisotropic velocity model of the North American upper mantle

    NASA Astrophysics Data System (ADS)

    Yuan, Huaiyu; Romanowicz, Barbara; Fischer, Karen M.; Abt, David

    2011-03-01

    Using a combination of long period seismic waveforms and SKS splitting measurements, we have developed a 3-D upper-mantle model (SAWum_NA2) of North America that includes isotropic shear velocity, with a lateral resolution of ˜250 km, as well as radial and azimuthal anisotropy, with a lateral resolution of ˜500 km. Combining these results, we infer several key features of lithosphere and asthenosphere structure. A rapid change from thin (˜70-80 km) lithosphere in the western United States (WUS) to thick lithosphere (˜200 km) in the central, cratonic part of the continent closely follows the Rocky Mountain Front (RMF). Changes with depth of the fast axis direction of azimuthal anisotropy reveal the presence of two layers in the cratonic lithosphere, corresponding to the fast-to-slow discontinuity found in receiver functions. Below the lithosphere, azimuthal anisotropy manifests a maximum, stronger in the WUS than under the craton, and the fast axis of anisotropy aligns with the absolute plate motion, as described in the hotspot reference frame (HS3-NUVEL 1A). In the WUS, this zone is confined between 70 and 150 km, decreasing in strength with depth from the top, from the RMF to the San Andreas Fault system and the Juan de Fuca/Gorda ridges. This result suggests that shear associated with lithosphere-asthenosphere coupling dominates mantle deformation down to this depth in the western part of the continent. The depth extent of the zone of increased azimuthal anisotropy below the cratonic lithosphere is not well resolved in our study, although it is peaked around 270 km, a robust result. Radial anisotropy is such that, predominantly, ξ > 1, where ξ= (Vsh/Vsv)2, under the continent and its borders down to ˜200 km, with stronger ξ in the bordering oceanic regions. Across the continent and below 200 km, alternating zones of weaker and stronger radial anisotropy, with predominantly ξ < 1, correlate with zones of small lateral changes in the fast axis direction of

  7. 3-D finite-difference, finite-element, discontinuous-Galerkin and spectral-element schemes analysed for their accuracy with respect to P-wave to S-wave speed ratio

    NASA Astrophysics Data System (ADS)

    Moczo, Peter; Kristek, Jozef; Galis, Martin; Chaljub, Emmanuel; Etienne, Vincent

    2011-12-01

    We analyse 13 3-D numerical time-domain explicit schemes for modelling seismic wave propagation and earthquake motion for their behaviour with a varying P-wave to S-wave speed ratio (VP/VS). The second-order schemes include three finite-difference, three finite-element and one discontinuous-Galerkin schemes. The fourth-order schemes include three finite-difference and two spectral-element schemes. All schemes are second-order in time. We assume a uniform cubic grid/mesh and present all schemes in a unified form. We assume plane S-wave propagation in an unbounded homogeneous isotropic elastic medium. We define relative local errors of the schemes in amplitude and the vector difference in one time step and normalize them for a unit time. We also define the equivalent spatial sampling ratio as a ratio at which the maximum relative error is equal to the reference maximum error. We present results of the extensive numerical analysis. We theoretically (i) show how a numerical scheme sees the P and S waves if the VP/VS ratio increases, (ii) show the structure of the errors in amplitude and the vector difference and (iii) compare the schemes in terms of the truncation errors of the discrete approximations to the second mixed and non-mixed spatial derivatives. We find that four of the tested schemes have errors in amplitude almost independent on the VP/VS ratio. The homogeneity of the approximations to the second mixed and non-mixed spatial derivatives in terms of the coefficients of the leading terms of their truncation errors as well as the absolute values of the coefficients are key factors for the behaviour of the schemes with increasing VP/VS ratio. The dependence of the errors in the vector difference on the VP/VS ratio should be accounted for by a proper (sufficiently dense) spatial sampling.

  8. 3D P-wave velocity structure of the deep Galicia rifted margin: A first analysis of the Galicia 3D wide-angle seismic dataset

    NASA Astrophysics Data System (ADS)

    Bayrakci, Gaye; Minshull, Timothy A.; Davy, Richard G.; Karplus, Marianne S.; Kaeschen, Dirk; Papenberg, Cord; Krabbenhoeft, Anne; Sawyer, Dale; Reston, Timothy J.; Shillington, Donna J.; Ranero, César R.

    2014-05-01

    Galicia 3D, a reflection-refraction and long offset seismic experiment was carried out from May through September 2013, at the Galicia rifted margin (in the northeast Atlantic Ocean, west of Spain) as a collaboration between US, UK, German and Spanish groups. The 3D multichannel seismic acquisition conducted by R/V Marcus Langseth covered a 64 km by 20 km (1280 km2) zone where the main geological features are the Peridotite Ridge (PR), composed of serpentinized peridotite and thought be upper mantle exhumed to the seafloor during rifting, and the S reflector which has been interpreted to be a low angle detachment fault overlain by fault bounded, rotated, continental crustal blocks. In the 3D box, two airgun arrays of 3300 cu.in. were fired alternately (in flip-flop configuration) every 37.5 m. All shots are recorded by 44 short period four component ocean bottom seismometers (OBS) and 26 ocean bottom hydrophones (OBH) deployed and recovered by R/V Poseidon, as well as four 6 km hydrophone streamers with 12.5 m channel spacing towed by R/V Marcus Langseth. We present the preliminary results of the first arrival time tomography study which is carried out with a subset of the wide-angle dataset, in order to generate a 3D P-wave velocity volume for the entire depth sampled by the reflection data. After the relocation of OBSs and OBHs, an automatic first-arrival time picking approach is applied to a subset of the dataset, which comprises more than 5.5 million source-receiver pairs. Then, the first-arrival times are checked visually, in 3-dimensions. The a priori model used for the first-arrival time tomography is built up using information from previous seismic surveys carried out at the Galicia margin (e.g. ISE, 1997). The FAST algorithm of Zelt and Barton (1998) is used for the first-arrival time inversion. The 3D P-wave velocity volume can be used in interpreting the reflection dataset, as a starting point for migration, to quantify the thinning of the crustal layers

  9. A hybrid experimental-numerical technique for determining 3D velocity fields from planar 2D PIV data

    NASA Astrophysics Data System (ADS)

    Eden, A.; Sigurdson, M.; Mezić, I.; Meinhart, C. D.

    2016-09-01

    Knowledge of 3D, three component velocity fields is central to the understanding and development of effective microfluidic devices for lab-on-chip mixing applications. In this paper we present a hybrid experimental-numerical method for the generation of 3D flow information from 2D particle image velocimetry (PIV) experimental data and finite element simulations of an alternating current electrothermal (ACET) micromixer. A numerical least-squares optimization algorithm is applied to a theory-based 3D multiphysics simulation in conjunction with 2D PIV data to generate an improved estimation of the steady state velocity field. This 3D velocity field can be used to assess mixing phenomena more accurately than would be possible through simulation alone. Our technique can also be used to estimate uncertain quantities in experimental situations by fitting the gathered field data to a simulated physical model. The optimization algorithm reduced the root-mean-squared difference between the experimental and simulated velocity fields in the target region by more than a factor of 4, resulting in an average error less than 12% of the average velocity magnitude.

  10. Assessment of earthquake locations in 3-D deterministic velocity models: A case study from the Altotiberina Near Fault Observatory (Italy)

    NASA Astrophysics Data System (ADS)

    Latorre, D.; Mirabella, F.; Chiaraluce, L.; Trippetta, F.; Lomax, A.

    2016-11-01

    The accuracy of earthquake locations and their correspondence with subsurface geology depends strongly on the accuracy of the available seismic velocity model. Most modern methods to construct a velocity model for earthquake location are based on the inversion of passive source seismological data. Another approach is the integration of high-resolution geological and geophysical data to construct deterministic velocity models in which earthquake locations can be directly correlated to the geological structures. Such models have to be kinematically consistent with independent seismological data in order to provide precise hypocenter solutions. We present the Altotiberina (AT) seismic model, a three-dimensional velocity model for the Upper Tiber Valley region (Northern Apennines, Italy), constructed by combining 300 km of seismic reflection profiles, six deep boreholes (down to 5 km depth), detailed data from geological surveys and direct measurements of P and S wave velocities performed in situ and in laboratory. We assess the robustness of the AT seismic model by locating 11,713 earthquakes with a nonlinear, global-search inversion method and comparing the probabilistic hypocenter solutions to those calculated in three previously published velocity models, constructed by inverting passive seismological data only. Our results demonstrate that the AT seismic model is able to provide higher-quality hypocenter locations than the previous velocity models. Earthquake locations are consistent with the subsurface geological structures and show a high degree of spatial correlation with specific lithostratigraphic units, suggesting a lithological control on the seismic activity evolution.

  11. Quantification of velocity reduction after flow diverter placement in intracranial aneurysm: An ex vivo study with 3D printed replicas.

    PubMed

    Anderson, Jeff R; Klucznik, Richard; Diaz, Orlando; Zhang, Y Jonathan; Britz, Gavin W; Grossman, Robert G; Karmonik, Christof

    2015-01-01

    Phase contrast MRI (pcMRI) was used to measure flow before and after placement of a flow diverter (n = 3). Decreases from 18% to 31% in flow velocity were seen in the inflow jet of the aneurysms. Flow patterns were also compared. It was observed that the gross aneurysmal flow patterns were maintained after flow diverter placement despite decreased fluid velocities. All measurements were carried out in 3D printed aneurysm replicas.

  12. Low-Velocity Impact Response and Finite Element Analysis of Four-Step 3-D Braided Composites

    NASA Astrophysics Data System (ADS)

    Sun, Baozhong; Zhang, Yan; Gu, Bohong

    2013-08-01

    The low-velocity impact characters of 3-D braided carbon/epoxy composites were investigated from experimental and finite element simulation approaches. The quasi-static tests were carried out at a constant velocity of 2 mm/min on MTS 810.23 material tester system to obtain the indentation load-displacement curves and indentation damages. The low-velocity tests were conducted at the velocities from 1 m/s to 6 m/s (corresponding to the impact energy from 3.22 J to 116 J) on Instron Dynatup 9250 impact tester. The peak force, energy for peak force, time to peak force, and total energy absorption were obtained to determine the impact responses of 3-D braided composites. A unit cell model was established according to the microstructure of 3-D braided composites to derive the constitutive equation. Based on the model, a user-defined material subroutine (VUMAT) has been compiled by FORTRAN and connected with commercial finite element code ABAQUS/Explicit to calculate the impact damage. The unit cell model successfully predicted the impact response of 3-D braided composites. Furthermore, the stress wave propagation and failure mechanisms have been revealed from the finite element simulation results and ultimate damage morphologies of specimens.

  13. Surface seismic measurements of near-surface P-and S-wave seismic velocities at earthquake recording stations, Seattle, Washington

    USGS Publications Warehouse

    Williams, R.A.; Stephenson, W.J.; Frankel, A.D.; Odum, J.K.

    1999-01-01

    We measured P-and S-wave seismic velocities to about 40-m depth using seismic-refraction/reflection data on the ground surface at 13 sites in the Seattle, Washington, urban area, where portable digital seismographs recently recorded earthquakes. Sites with the lowest measured Vs correlate with highest ground motion amplification. These sites, such as at Harbor Island and in the Duwamish River industrial area (DRIA) south of the Kingdome, have an average Vs in the upper 30 m (V??s30) of 150 to 170 m/s. These values of V??s30 place these sites in soil profile type E (V??s30 < 180 m/s). A "rock" site, located at Seward Park on Tertiary sedimentary deposits, has a V??S30 of 433 m/s, which is soil type C (V??s30: 360 to 760 m/s). The Seward Park site V??s30 is about equal to, or up to 200 m/s slower than sites that were located on till or glacial outwash. High-amplitude P-and S-wave seismic reflections at several locations appear to correspond to strong resonances observed in earthquake spectra. An S-wave reflector at the Kingdome at about 17 to 22 m depth probably causes strong 2-Hz resonance that is observed in the earthquake data near the Kingdome.

  14. A Detailed 3D Seismic Velocity Structure of the Subducting Pacific Slab Beneath Hokkaido, Tohoku and Kanto, Japan, by Double-Difference Tomography

    NASA Astrophysics Data System (ADS)

    Tsuji, Y.; Nakajima, J.; Kita, S.; Okada, T.; Matsuzawa, T.; Hasegawa, A.

    2007-12-01

    Three-dimensional heterogeneous structure beneath northeastern (NE) Japan has been investigated by previous studies and an inclined seismic low-velocity zone is imaged in the mantle wedge sub-parallel to the down-dip direction of the subducting slab (Zhao et al., 1992, Nakajima et al., 2001). However, the heterogeneous structure within the slab has not been well studied even though it is very important to understand the whole process of water transportation from the slab to the surface. Here we show a detailed 3D seismic velocity structure within the subducted Pacific slab around Japan and propose a water-transportation path from the slab to the mantle wedge. In this study, we estimated 3D velocity structure within the Pacific slab by the double-difference tomography (Zhang and Thurber, 2003). We divided the study area, from Hokkaido to Kanto, into 6 areas due to the limitation of memory and computation time. In each area, arrival-time data of 7,500-17,000 events recorded at 70-170 stations were used in the analysis. The total number of absolute travel-time data was about 140,000-312,000 for P wave and 123,000-268,000 for S wave, and differential data were about 736,000-1,920,000 for P wave and 644,000-1,488,000 for S wave. Horizontal and vertical grid separations are 10-25 km and 6.5 km, respectively. RMS residuals of travel times for P wave decreased from 0.23s to 0.09s and for S wave from 0.35s to 0.13s. The obtained results are as follows: (1) a remarkable low-Vs zone exists in the uppermost part of the subducting slab, (2) it extends down to a depth of about 80 km, (3) the termination of this low-Vs zone almost corresponds to the "seismic belt" recently detected in the upper plane of the double seismic zone (Kita et al.,2006; Hasegawa et al., 2007), (4) at depths deeper than 80 km, a low-Vs and high-Vp/Vs zone is apparently distributed in the mantle wedge, immediately above the slab crust. We consider that these features reflect water-transportation processes

  15. A genetic algorithm particle pairing technique for 3D velocity field extraction in holographic particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Sheng, J.; Meng, H.

    This research explores a novel technique, using Genetic Algorithm Particle Pairing (GAPP) to extract three-dimensional (3D) velocity fields of complex flows. It is motivated by Holographic Particle Image Velocimetry (HPIV), in which intrinsic speckle noise hinders the achievement of high particle density required for conventional correlation methods in extracting 3D velocity fields, especially in regions with large velocity gradients. The GA particle pairing method maps particles recorded at the first exposure to those at the second exposure in a 3D space, providing one velocity vector for each particle pair instead of seeking statistical averaging. Hence, particle pairing can work with sparse seeding and complex 3D velocity fields. When dealing with a large number of particles from two instants, however, the accuracy of pairing results and processing speed become major concerns. Using GA's capability to search a large solution space parallelly, our algorithm can efficiently find the best mapping scenarios among a large number of possible particle pairing schemes. During GA iterations, different pairing schemes or solutions are evaluated based on fluid dynamics. Two types of evaluation functions are proposed, tested, and embedded into the GA procedures. Hence, our Genetic Algorithm Particle Pairing (GAPP) technique is characterized by robustness in velocity calculation, high spatial resolution, good parallelism in handling large data sets, and high processing speed on parallel architectures. It has been successfully tested on a simple HPIV measurement of a real trapped vortex flow as well as a series of numerical experiments. In this paper, we introduce the principle of GAPP, analyze its performance under different parameters, and evaluate its processing speed on different computer architectures.

  16. Application of the H/V and SPAC Method to Estimate a 3D Shear Wave Velocity Model, in the City of Coatzacoalcos, Veracruz.

    NASA Astrophysics Data System (ADS)

    Morales, L. E. A. P.; Aguirre, J.; Vazquez Rosas, R.; Suarez, G.; Contreras Ruiz-Esparza, M. G.; Farraz, I.

    2014-12-01

    Methods that use seismic noise or microtremors have become very useful tools worldwide due to its low costs, the relative simplicity in collecting data, the fact that these are non-invasive methods hence there is no need to alter or even perforate the study site, and also these methods require a relatively simple analysis procedure. Nevertheless the geological structures estimated by this methods are assumed to be parallel, isotropic and homogeneous layers. Consequently precision of the estimated structure is lower than that from conventional seismic methods. In the light of these facts this study aimed towards searching a new way to interpret the results obtained from seismic noise methods. In this study, seven triangular SPAC (Aki, 1957) arrays were performed in the city of Coatzacoalcos, Veracruz, varying in sizes from 10 to 100 meters. From the autocorrelation between the stations of each array, a Rayleigh wave phase velocity dispersion curve was calculated. Such dispersion curve was used to obtain a S wave parallel layers velocity (VS) structure for the study site. Subsequently the horizontal to vertical ratio of the spectrum of microtremors H/V (Nogoshi and Igarashi, 1971; Nakamura, 1989, 2000) was calculated for each vertex of the SPAC triangular arrays, and from the H/V spectrum the fundamental frequency was estimated for each vertex. By using the H/V spectral ratio curves interpreted as a proxy to the Rayleigh wave ellipticity curve, a series of VS structures were inverted for each vertex of the SPAC array. Lastly each VS structure was employed to calculate a 3D velocity model, in which the exploration depth was approximately 100 meters, and had a velocity range in between 206 (m/s) to 920 (m/s). The 3D model revealed a thinning of the low velocity layers. This proved to be in good agreement with the variation of the fundamental frequencies observed at each vertex. With the previous kind of analysis a preliminary model can be obtained as a first

  17. Developing a 3D constrained variational analysis method to obtain accurate gridded atmospheric vertical velocity and horizontal advections

    NASA Astrophysics Data System (ADS)

    Tang, S.; Zhang, M.

    2013-12-01

    Based on the constrained variational analysis (CVA) algorithm developed by Zhang and Lin (1997), a 3-dimensional (3D) version of CVA is developed. The new algorithm used gridded surface and TOA observations as constraints to adjust atmospheric state variables in each grid point to satisfy column-integrated mass, moisture and static energy conservation. From the process of adjustment a set of high-quality 3D large-scale forcing data (vertical velocity and horizontal advections) can be derived to drive Single-Column models (SCM), Cloud-Resolving Models (CRM) and Large-Eddy Simulations (LES) to evaluate and improve parameterizations. Since the 3D CVA can adjust gridded state variables from any data source with observed precipitation, radiation and surface fluxes, it also gives a potential possibility to use this algorithm in data assimilation system to assimilate precipitation and radiation data.

  18. Temporal variation of the Rayleigh admittance: Implication for S-wave velocity changes in the toe of the Nankai accretionary prism

    NASA Astrophysics Data System (ADS)

    Tonegawa, Takashi; Araki, Eiichiro; Kimura, Toshinori; Nakamura, Takeshi

    2016-04-01

    A cabled seafloor network with 20 stations (DONET: Dense Oceanfloor Network System for Earthquake and Tsunamis) has been constructed on the accretionary prism at the Nankai subduction zone of Japan between March 2010 and August 2011, which means that the observation period became more than 4 years. Each station contains broadband seismometers and absolute and differential pressure gauges. In this study, we estimated the Rayleigh admittance at the seafloor for each station, i.e., an amplitude transfer function from pressure to displacement in the frequency band of microseisms, particularly for the fundamental Rayleigh mode of 0.1-0.2 Hz. The pattern of the transfer function depends on the S-wave velocity structure at shallow depths beneath stations (Ruan et al., 2014, JGR). Therefore, plotting the Rayleigh admittance as functions of time and frequency, we investigated temporal variations of S-wave velocity within the accretionary prism. We calculated the displacement seismogram by removing the instrument response from the velocity seismogram for each station. The pressure record observed at the differential pressure gauge was used in this study because of a high resolution of the pressure observation. In the frequency domain, we smoothed the two kinds of spectra (displacement and pressure) with ±2 neighboring samples, and estimated the amplitude transfer function of displacement/pressure. Here, we used the ambient noise of the two records. To display their temporal variations, we plot the averaged transfer function with intervals of 7 days. As a result, we found a long-term temporal variation of the Rayleigh admittance at two stations. These stations are located at the southern part of the array and near the trench, where the activities of very-low frequency earthquakes (VLFEs) within the accretionary prism on 2004, 2009, and 2011 have been previously reported. The admittance at a frequency of 0.1 Hz has gradually decreased during the observation period, which

  19. Segment-interaction in sprint start: Analysis of 3D angular velocity and kinetic energy in elite sprinters.

    PubMed

    Slawinski, J; Bonnefoy, A; Ontanon, G; Leveque, J M; Miller, C; Riquet, A; Chèze, L; Dumas, R

    2010-05-28

    The aim of the present study was to measure during a sprint start the joint angular velocity and the kinetic energy of the different segments in elite sprinters. This was performed using a 3D kinematic analysis of the whole body. Eight elite sprinters (10.30+/-0.14s 100 m time), equipped with 63 passive reflective markers, realised four maximal 10 m sprints start on an indoor track. An opto-electronic Motion Analysis system consisting of 12 digital cameras (250 Hz) was used to collect the 3D marker trajectories. During the pushing phase on the blocks, the 3D angular velocity vector and its norm were calculated for each joint. The kinetic energy of 16 segments of the lower and upper limbs and of the total body was calculated. The 3D kinematic analysis of the whole body demonstrated that joints such as shoulders, thoracic or hips did not reach their maximal angular velocity with a movement of flexion-extension, but with a combination of flexion-extension, abduction-adduction and internal-external rotation. The maximal kinetic energy of the total body was reached before clearing block (respectively, 537+/-59.3 J vs. 514.9+/-66.0 J; p< or =0.01). These results suggested that a better synchronization between the upper and lower limbs could increase the efficiency of pushing phase on the blocks. Besides, to understand low interindividual variances in the sprint start performance in elite athletes, a 3D complete body kinematic analysis shall be used.

  20. Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

    DOE PAGES

    Debnath, Mithu; Iungo, G. Valerio; Ashton, Ryan; ...

    2017-02-06

    Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved with goodmore » accuracy. However, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.« less

  1. Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

    SciTech Connect

    Debnath, Mithu; Iungo, G. Valerio; Ashton, Ryan; Brewer, W. Alan; Choukulkar, Aditya; Delgado, Ruben; Lundquist, Julie K.; Shaw, William J.; Wilczak, James M.; Wolfe, Daniel

    2017-01-01

    Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved with good accuracy. However, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.

  2. Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

    NASA Astrophysics Data System (ADS)

    Debnath, Mithu; Valerio Iungo, G.; Ashton, Ryan; Brewer, W. Alan; Choukulkar, Aditya; Delgado, Ruben; Lundquist, Julie K.; Shaw, William J.; Wilczak, James M.; Wolfe, Daniel

    2017-02-01

    Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved with good accuracy. However, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.

  3. On the critical one-component velocity regularity criteria to 3-D incompressible MHD system

    NASA Astrophysics Data System (ADS)

    Liu, Yanlin

    2016-05-01

    Let (u , b) be a smooth enough solution of 3-D incompressible MHD system. We prove that if (u , b) blows up at a finite time T*, then for any p ∈ ] 4 , ∞ [, there holds ∫0T* (‖u3(t‧) ‖ H ˙ 1/2 +2/p p + ‖b(t‧) ‖ H ˙ 1/2 +2/p p) dt‧ = ∞. We remark that all these quantities are in the critical regularity of the MHD system.

  4. 3D Velocity and Density Model of the Los Angeles Basin and Spectral Element Method Earthquake Simulations

    NASA Astrophysics Data System (ADS)

    Suess, P.; Shaw, J. H.; Komatitsch, D.; Tromp, J.

    2001-12-01

    We present a 3D velocity model and a 3D density model of the LA basin. The LA basin velocity model was constructed using sonic log and stacking velocity information, provided by oil industry sources and not previously incorporated into southern California velocity models. The density model is based upon a new database of approximately 300 oil industry density logs from across the Los Angeles basin. These logs use gamma ray emissions to determine formation density at samples of about one meter. We have developed an empirical relation between sonic velocity and density by comparing data from approximately 30 wells in which we have both sonic and density logs. For the remaining wells, we have derived relationships between depth and density, and characterized this relationship for the three main stratigraphic sub-divisions of the SCEC Phase 2 model (Quaternary to base Pico Fm., top Repetto Fm. to top Mohnian, and top Mohnian to basement). The density-depth and density-velocity relations will provide independent rules that can be employed to define density and velocity structure in areas where data does not exist, or in other areas with similar lithology to the Los Angeles basin. We use a spectral element method (SEM) for simulation of seismic wave propagation which is currently being implemented on a 156-node Pentium PC cluster at Cal Tech. Preliminary work shows that SEM results using a 1D velocity model for southern California compare very well to discrete-wavenumber results. Both the density structure and velocity structure must be defined in a 3D model for its use in simulations of seismic wave propagation with a spectral element method, to predict the distribution of hazardous ground shaking during large events. Previous work has typically used density values which were predicted by the sonic velocity values; use of our measured density values should provide more accurate ground shaking predictions, and comparison to previous results will provide a useful

  5. Mantle Composition and Temperature of Western North America Revealed from Direct P and S Wave Velocities of KLB-1 Peridotite to the Condition of Transition Zone

    NASA Astrophysics Data System (ADS)

    Wang, X.; Chen, T.; Qi, X.; Zou, Y.; Liebermann, R. C.; Li, B.

    2015-12-01

    Comparing the elasticity of candidate compositional models with seismic profiles (e.g., PREM and AK135) is one of the most important geophysical approaches to constrain the mineralogical composition of the mantle. However in such averaging schemes (e.g., Voigt-Reuss-Hill), it is difficult to take into account all of the mineralogical and chemical complexities; we therefore undertook elasticity study of a natural mantle rock sample at high pressures and temperatures. In this study, a series of polycrystalline aggregates of peridotite KLB-1 (from Kilbourne Hole, New Mexico) were hot-pressed at pressures of 3-15 GPa and temperatures of 1200-1400°C. Scanning electron microscopy (SEM), Electron Microprobe Analysis (EPMA) and X-ray diffraction (XRD) were used to characterize the texture, grain size, and composition of these well-sintered specimens. For the first time in history, the P and S wave velocities of a pyrolitic multiphase aggregate were directly measured at mantle transition zone pressures and temperatures using ultrasonic interferometry. Based on the phase fractions from EPMA and the P and S wave velocities from in situ measurement at high pressure and high temperature, the velocities of the KLB-1 peridotite along 1200-1400 oC adiabatic mantle geotherms were obtained and compare well with the seismic models of western North America, the region where these peridotite KLB-1 samples were collected. The comparison with regional seismic models of western North America (e.g., GCA and TNA/TNA2) as well as global seismic models (PREM and AK135) place unprecedented constraints on the composition, temperature and density profiles for the upper mantle in this region, which can help us understand the nature of thermal and tectonic processes of the Rio Grande Rift.

  6. A 3-D shear velocity model of the southern North American and Caribbean plates from ambient noise and earthquake tomography

    NASA Astrophysics Data System (ADS)

    Gaite, B.; Villaseñor, A.; Iglesias, A.; Herraiz, M.; Jiménez-Munt, I.

    2015-02-01

    We use group velocities from earthquake tomography together with group and phase velocities from ambient noise tomography (ANT) of Rayleigh waves to invert for the 3-D shear-wave velocity structure (5-70 km) of the Caribbean (CAR) and southern North American (NAM) plates. The lithospheric model proposed offers a complete image of the crust and uppermost-mantle with imprints of the tectonic evolution. One of the most striking features inferred is the main role of the Ouachita-Marathon-Sonora orogeny front on the crustal seismic structure of the NAM plate. A new imaged feature is the low crustal velocities along the USA-Mexico border. The model also shows a break of the east-west mantle velocity dichotomy of the NAM and CAR plates beneath the Isthmus of the Tehuantepec and the Yucatan Block. High upper-mantle velocities along the Mesoamerican Subduction Zone coincide with inactive volcanic areas while the lowest velocities correspond to active volcanic arcs and thin lithospheric mantle regions.

  7. Estimating 3D positions and velocities of projectiles from monocular views.

    PubMed

    Ribnick, Evan; Atev, Stefan; Papanikolopoulos, Nikolaos P

    2009-05-01

    In this paper, we consider the problem of localizing a projectile in 3D based on its apparent motion in a stationary monocular view. A thorough theoretical analysis is developed, from which we establish the minimum conditions for the existence of a unique solution. The theoretical results obtained have important implications for applications involving projectile motion. A robust, nonlinear optimization-based formulation is proposed, and the use of a local optimization method is justified by detailed examination of the local convexity structure of the cost function. The potential of this approach is validated by experimental results.

  8. Characterizing 3-D flow velocity in evolving pore networks driven by CaCO3 precipitation and dissolution

    NASA Astrophysics Data System (ADS)

    Chojnicki, K. N.; Yoon, H.; Martinez, M. J.

    2015-12-01

    Understanding reactive flow in geomaterials is important for optimizing geologic carbon storage practices, such as using pore space efficiently. Flow paths can be complex in large degrees of geologic heterogeneities across scales. In addition, local heterogeneity can evolve as reactive transport processes alter the pore-scale morphology. For example, dissolved carbon dioxide may react with minerals in fractured rocks, confined aquifers, or faults, resulting in heterogeneous cementation (and/or dissolution) and evolving flow conditions. Both path and flow complexities are important and poorly characterized, making it difficult to determine their evolution with traditional 2-D transport models. Here we characterize the development of 3-D pore-scale flow with an evolving pore configuration due to calcium carbonate (CaCO3) precipitation and dissolution. A simple pattern of a microfluidic pore network is used initially and pore structures will become more complex due to precipitation and dissolution processes. At several stages of precipitation and dissolution, we directly visualize 3-D velocity vectors using micro particle image velocimetry and a laser scanning confocal microscope. Measured 3-D velocity vectors are then compared to 3-D simulated flow fields which will be used to simulate reactive transport. Our findings will highlight the importance of the 3-D flow dynamics and its impact on estimating reactive surface area over time. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. This material is based upon work supported as part of the Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001114.

  9. Modeling and validation of a 3D velocity structure for the Santa Clara Valley, California, for seismic-wave simulations

    USGS Publications Warehouse

    Hartzell, S.; Harmsen, S.; Williams, R.A.; Carver, D.; Frankel, A.; Choy, G.; Liu, P.-C.; Jachens, R.C.; Brocher, T.M.; Wentworth, C.M.

    2006-01-01

    A 3D seismic velocity and attenuation model is developed for Santa Clara Valley, California, and its surrounding uplands to predict ground motions from scenario earthquakes. The model is developed using a variety of geologic and geophysical data. Our starting point is a 3D geologic model developed primarily from geologic mapping and gravity and magnetic surveys. An initial velocity model is constructed by using seismic velocities from boreholes, reflection/refraction lines, and spatial autocorrelation microtremor surveys. This model is further refined and the seismic attenuation is estimated through waveform modeling of weak motions from small local events and strong-ground motion from the 1989 Loma Prieta earthquake. Waveforms are calculated to an upper frequency of 1 Hz using a parallelized finite-difference code that utilizes two regions with a factor of 3 difference in grid spacing to reduce memory requirements. Cenozoic basins trap and strongly amplify ground motions. This effect is particularly strong in the Evergreen Basin on the northeastern side of the Santa Clara Valley, where the steeply dipping Silver Creek fault forms the southwestern boundary of the basin. In comparison, the Cupertino Basin on the southwestern side of the valley has a more moderate response, which is attributed to a greater age and velocity of the Cenozoic fill. Surface waves play a major role in the ground motion of sedimentary basins, and they are seen to strongly develop along the western margins of the Santa Clara Valley for our simulation of the Loma Prieta earthquake.

  10. On the Quality of Velocity Interpolation Schemes for Marker-In-Cell Methods on 3-D Staggered Grids

    NASA Astrophysics Data System (ADS)

    Kaus, B.; Pusok, A. E.; Popov, A.

    2015-12-01

    The marker-in-cell method is generally considered to be a flexible and robust method to model advection of heterogenous non-diffusive properties (i.e. rock type or composition) in geodynamic problems or incompressible Stokes problems. In this method, Lagrangian points carrying compositional information are advected with the ambient velocity field on an immobile, Eulerian grid. However, velocity interpolation from grid points to marker locations is often performed without preserving the zero divergence of the velocity field at the interpolated locations (i.e. non-conservative). Such interpolation schemes can induce non-physical clustering of markers when strong velocity gradients are present (Jenny et al., 2001) and this may, eventually, result in empty grid cells, a serious numerical violation of the marker-in-cell method. Solutions to this problem include: using larger mesh resolutions and/or marker densities, or repeatedly controlling the marker distribution (i.e. inject/delete), but which does not have an established physical background. To remedy this at low computational costs, Jenny et al. (2001) and Meyer and Jenny (2004) proposed a simple, conservative velocity interpolation (CVI) scheme for 2-D staggered grid, while Wang et al. (2015) extended the formulation to 3-D finite element methods. Here, we follow up with these studies and report on the quality of velocity interpolation methods for 2-D and 3-D staggered grids. We adapt the formulations from both Jenny et al. (2001) and Wang et al. (2015) for use on 3-D staggered grids, where the velocity components have different node locations as compared to finite element, where they share the same node location. We test the different interpolation schemes (CVI and non-CVI) in combination with different advection schemes (Euler, RK2 and RK4) and with/out marker control on Stokes problems with strong velocity gradients, which are discretized using a finite difference method. We show that a conservative formulation

  11. Final Data Report: P- and S-Wave Velocity Logging Borings C4993, C4996, and C4997 Part A: Interval Logs

    SciTech Connect

    Steller, Robert; Diehl, John

    2007-02-01

    Insitu borehole P- and S-wave velocity measurements were collected in three borings located within the Waste Treatment Plant (WTP) boundaries at the Hanford Site, southeastern Washington. Geophysical data acquisition was performed between August and October of 2006 by Rob Steller, Charles Carter, Antony Martin and John Diehl of GEOVision. Data analysis was performed by Rob Steller and John Diehl, and reviewed by Antony Martin of GEOVision, and report preparation was performed by John Diehl and reviewed by Rob Steller. The work was performed under subcontract with Battelle, Pacific Northwest Division with Marty Gardner as Battelle’s Technical Representative and Alan Rohay serving as the Technical Administrator for Pacific Northwest National Laboratory (PNNL). This report describes the field measurements, data analysis, and results of this work.

  12. Application of microtremor array measurements to delineate S-wave velocity structures in Bangkok Basin, central Thailand

    NASA Astrophysics Data System (ADS)

    Hayashi, K.; Pananont, P.; Wongpanit, T.; Habangkham, S.

    2014-12-01

    The Bangkok Basin, located in the lower part of the Chao Phraya River Basin in central Thailand contains very thick sediment and are often affected by the large distant earthquakes due to local site amplification. Shear wave velocities (Vs) measurements have been performed at five sites in the Bangkok Basin (Figure 1) by a two-station spatial autocorrelation method (2ST-SPAC) using long-period accelerometers. Receiver separation varied from 5 to 2,100m and maximum separation (array size) varied from 1,800 to 2,100 m. In each separation, 10 to 90 minutes ambient noise was recorded with sampling interval of 10 ms. Due to the security concern, data acquisition was performed in the day-time and in relatively quiet places such as in parks or less densely residential areas. A spatial autocorrelation was used for calculating phase velocity and clear dispersion curves were obtained in frequency range from about 0.3 to 10 Hz. Minimum frequency and corresponding maximum wavelength ranged from 0.32 to 0.48 Hz and about 2,180 to 5,140 m, depending on the site. An inversion consisting of a least squares method and a Genetic Algorithm was used to estimate Vs profiles from the dispersion curves to a depth of about 1,000 to 2,500 m depending on the sites. Figure 2 shows comparison of Vs profiles obtained by the inversion. We can see that a low velocity layer with Vs lower than 400 m/s exists between depths of 0 to 200 m at all sites. Intermediate bedrock with Vs higher than 1,000 m/s exists between depths of 240 to 1,250 m. Deepest bedrock with Vs higher than 2,000 m/s seems to exist at a depth of at least 1,600 m.

  13. A compendium of P- and S-wave velocities from surface-to-borehole logging; summary and reanalysis of previously published data and analysis of unpublished data

    USGS Publications Warehouse

    Boore, David M.

    2003-01-01

    For over 28 years, the U.S. Geological Survey (USGS) has been acquiring seismic velocity and geologic data at a number of locations in California, many of which were chosen because strong ground motions from earthquakes were recorded at the sites. The method for all measurements involves picking first arrivals of P- and S-waves from a surface source recorded at various depths in a borehole (as opposed to noninvasive methods, such as the SASW method [e.g., Brown et al., 2002]). The results from most of the sites are contained in a series of U.S. Geological Survey Open-File Reports (see References). Until now, none of the results have been available as computer files, and before 1992 the interpretation of the arrival times was in terms of piecemeal interval velocities, with no attempt to derive a layered model that would fit the travel times in an overall sense (the one exception is Porcella, 1984). In this report I reanalyze all of the arrival times in terms of layered models for P- and for S-wave velocities at each site, and I provide the results as computer files. In addition to the measurements reported in the open-file reports, I also include some borehole results from other reports, as well as some results never before published. I include data for 277 boreholes (at the time of this writing; more will be added to the web site as they are obtained), all in California (I have data from boreholes in Washington and Utah, but these will be published separately). I am also in the process of interpreting travel time data obtained using a seismic cone penetrometer at hundreds of sites; these data can be interpreted in the same way of those obtained from surface-to-borehole logging. When available, the data will be added to the web site (see below for information on obtaining data from the World Wide Web (WWW)). In addition to the basic borehole data and results, I provide information concerning strong-motion stations that I judge to be close enough to the boreholes

  14. Investigating particle phase velocity in a 3D spouted bed by a novel fiber high speed photography method

    NASA Astrophysics Data System (ADS)

    Qian, Long; Lu, Yong; Zhong, Wenqi; Chen, Xi; Ren, Bing; Jin, Baosheng

    2013-07-01

    A novel fiber high speed photography method has been developed to measure particle phase velocity in a dense gas-solid flow. The measurement system mainly includes a fiber-optic endoscope, a high speed video camera, a metal halide light source and a powerful computer with large memory. The endoscope which could be inserted into the reactors is used to form motion images of particles within the measurement window illuminated by the metal halide lamp. These images are captured by the high speed video camera and processed through a series of digital image processing algorithms, such as calibration, denoising, enhancement and binarization in order to improve the image quality. Then particles' instantaneous velocity is figured out by tracking each particle in consecutive frames. Particle phase velocity is statistically calculated according to the probability of particle velocity in each frame within a time period. This system has been applied to the investigation of particles fluidization characteristics in a 3D spouted bed. The experimental results indicate that the particle fluidization feature in the region investigated could be roughly classified into three sections by particle phase vertical velocity and the boundary between the first section and the second is the surface where particle phase velocity tends to be 0, which is in good agreement with the results published in other literature.

  15. Estimation of shallow S-wave velocity structure using microtremor array exploration at temporary strong motion observation stations for aftershocks of the 2016 Kumamoto earthquake

    NASA Astrophysics Data System (ADS)

    Chimoto, Kosuke; Yamanaka, Hiroaki; Tsuno, Seiji; Miyake, Hiroe; Yamada, Nobuyuki

    2016-12-01

    Shallow S-wave velocity V S profiles were estimated for 26 temporary strong motion observation sites surrounding the epicenters of a sequence of the 2016 Kumamoto earthquake. The microtremor array method was used to gather the dispersion characteristics of Rayleigh waves. V S profiles were obtained by inverting the dispersion curves for each site and those of three permanent strong motion stations that recorded the sequence of seismic events. The shallow V S profiles near two of the permanent strong motion stations in the town of Mashiki were almost identical. However, the V S profiles at other stations varied. The V S profiles were found to have the common feature of the uppermost low-velocity layer being widely distributed from Mashiki to the village of Minami-Aso, and it was especially thick in the areas that suffered heavy damage. This low-velocity layer was a major contributor to the site amplification. The horizontal-to-vertical spectral ratios of the microtremors indicate that both the shallow soil and deep sedimentary layers may control the site response characteristics over a broad frequency range.[Figure not available: see fulltext.

  16. Analysis of non linear partially standing waves from 3D velocity measurements

    NASA Astrophysics Data System (ADS)

    Drevard, D.; Rey, V.; Svendsen, Ib; Fraunie, P.

    2003-04-01

    Surface gravity waves in the ocean exhibit an energy spectrum distributed in both frequency and direction of propagation. Wave data collection is of great importance in coastal zones for engineering and scientific studies. In particular, partially standing waves measurements near coastal structures and steep or barred beaches may be a requirement, for instance for morphodynamic studies. The aim of the present study is the analysis of partially standing surface waves icluding non-linear effects. According to 1st order Stokes theory, synchronous measurements of horizontal and vertical velocity components allow calculation of rate of standing waves (Drevard et al, 2003). In the present study, it is demonstrated that for deep water conditions, partially standing 2nd order Stokes waves induced velocity field is still represented by the 1st order solution for the velocity potential contrary to the surface elevation which exhibits harmonic components. For intermediate water depth, harmonic components appear not only in the surface elevation but also in the velocity fields, but their weight remains much smaller, because of the vertical decreasing wave induced motion. For irregular waves, the influence of the spectrum width on the non-linear effects in the analysis is discussed. Keywords: Wave measurements ; reflection ; non-linear effects Acknowledgements: This work was initiated during the stay of Prof. Ib Svendsen, as invited Professor, at LSEET in autumn 2002. This study is carried out in the framework of the Scientific French National Programmes PNEC ART7 and PATOM. Their financial supports are acknowledged References: Drevard, D., Meuret, A., Rey, V. Piazzola, J. And Dolle, A.. (2002). "Partially reflected waves measurements using Acoustic Doppler Velocimeter (ADV)", Submitted to ISOPE 03, Honolulu, Hawaii, May 2003.

  17. Validated 3D Velocity Models in Asia from Joint Regional Body- and Surface-Wave Tomography

    DTIC Science & Technology

    2009-02-17

    90, 150 and 210 km. Some features of note in the new model include: • Crustal thickening beneath the major orogenic zones in the region...the low velocity area with respect to the background model beneath central Iran, which may have implications for the active subduction processes...occurring beneath the Eurasian continental collision zone . The slice on the right at 85°E cuts across the Himalayan Front, from northeastern India into

  18. Lapse-time-dependent coda-wave depth sensitivity to local velocity perturbations in 3-D heterogeneous elastic media

    NASA Astrophysics Data System (ADS)

    Obermann, Anne; Planès, Thomas; Hadziioannou, Céline; Campillo, Michel

    2016-10-01

    In the context of seismic monitoring, recent studies made successful use of seismic coda waves to locate medium changes on the horizontal plane. Locating the depth of the changes, however, remains a challenge. In this paper, we use 3-D wavefield simulations to address two problems: first, we evaluate the contribution of surface- and body-wave sensitivity to a change at depth. We introduce a thin layer with a perturbed velocity at different depths and measure the apparent relative velocity changes due to this layer at different times in the coda and for different degrees of heterogeneity of the model. We show that the depth sensitivity can be modelled as a linear combination of body- and surface-wave sensitivity. The lapse-time-dependent sensitivity ratio of body waves and surface waves can be used to build 3-D sensitivity kernels for imaging purposes. Second, we compare the lapse-time behaviour in the presence of a perturbation in horizontal and vertical slabs to address, for instance, the origin of the velocity changes detected after large earthquakes.

  19. P and S wave velocity measurements on sediments from the hanging-wall of megasplay fault, NantroSEIZE Stage 1

    NASA Astrophysics Data System (ADS)

    Hashimoto, Y.; Tobin, H. J.; Knuth, M. W.

    2010-12-01

    The evolution of elastic moduli in an accretionary prism setting provides insight into diagenetic and strengthening processes related to mechanical porosity decrease, cementation, strain history, and fluid release. Variability within the accretionary complex and along the decollement may have implications for wedge geometry, fluid migration, and seismogenesis. In this study, we describe the results of laboratory measurements of P-wave and S-wave velocities through sediments obtained from Sites C0001, C0002 and C0004. All sites are located in the hanging wall of the Mega-splay fault in the Nankai accretionary prism. We also made textural observations to examine the relationship between acoustic properties and textures, both within core samples and in the context of core-log-seismic integration. Our measurement procedure is as follows: Pore fluid pressure of 500kPa was applied and confining pressure was changed to control the effective pressure. The maximum effective pressure was estimated for each sample from the accumulation of the bulk density of sediments and hydrostatic pore fluid pressure at the depth of recovery. 1MHz Lead Zirconate Titanate (PZT) shear wave transducers are used in a source-receiver pair to measure wavespeed. PZT in a shear orientation generates a weak compressional mode in addition to its primary shear mode. This allowed us to identify P and S-wave arrivals in each test. The error can be as large as ~2 µs (about 5% error). Porosities are corrected to remove smectite effects from the on-board measured porosity. Porosity ranges ~0.6 - ~0.45, ~0.37 - ~0.27, and ~0.47 - ~0.39 for Site C0001, C0002, and C0004, respectively. P-wave velocity covered ~1630 km/s - 1990 km/s, ~2010 km/s - ~2370 km/s, and ~1700 km/s - ~2200 km/s for Site C0001, C0002 and Site C0004, respectively. S-wave velocity ranges from ~720 - ~950 m/s for Site C0002 samples and from ~650 - ~940 m/s for Site C0004. The Vp/Vs ratio ranged from ~2.4 - ~2.7 for Site C0002 and from ~2

  20. Study on 3-D velocity structure of crust and upper mantle in Sichuan-yunnan region, China

    USGS Publications Warehouse

    Wang, C.; Mooney, W.D.; Wang, X.; Wu, J.; Lou, H.; Wang, F.

    2002-01-01

    Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others appear the characteristic of tectonic boundary, indicating that the faults litely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the Sichuan-Yunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the Indian and the Asian plates. The crustal velocity in the Sichuan-Yunnan rhombic block generally shows normal.value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.

  1. Seismic moment tensor inversion using 3D velocity model and its application to the 2013 Lushan earthquake sequence

    NASA Astrophysics Data System (ADS)

    Zhu, Lupei; Zhou, Xiaofeng

    2016-10-01

    Source inversion of small-magnitude events such as aftershocks or mine collapses requires use of relatively high frequency seismic waveforms which are strongly affected by small-scale heterogeneities in the crust. In this study, we developed a new inversion method called gCAP3D for determining general moment tensor of a seismic source using Green's functions of 3D models. It inherits the advantageous features of the "Cut-and-Paste" (CAP) method to break a full seismogram into the Pnl and surface-wave segments and to allow time shift between observed and predicted waveforms. It uses grid search for 5 source parameters (relative strengths of the isotropic and compensated-linear-vector-dipole components and the strike, dip, and rake of the double-couple component) that minimize the waveform misfit. The scalar moment is estimated using the ratio of L2 norms of the data and synthetics. Focal depth can also be determined by repeating the inversion at different depths. We applied gCAP3D to the 2013 Ms 7.0 Lushan earthquake and its aftershocks using a 3D crustal-upper mantle velocity model derived from ambient noise tomography in the region. We first relocated the events using the double-difference method. We then used the finite-differences method and reciprocity principle to calculate Green's functions of the 3D model for 20 permanent broadband seismic stations within 200 km from the source region. We obtained moment tensors of the mainshock and 74 aftershocks ranging from Mw 5.2 to 3.4. The results show that the Lushan earthquake is a reverse faulting at a depth of 13-15 km on a plane dipping 40-47° to N46° W. Most of the aftershocks occurred off the main rupture plane and have similar focal mechanisms to the mainshock's, except in the proximity of the mainshock where the aftershocks' focal mechanisms display some variations.

  2. On the location of microseismic sources in instable rock slope areas: heterogeneous vs. homogenous 3D velocity models

    NASA Astrophysics Data System (ADS)

    Coviello, Velio; Manconi, Andrea; Occhiena, Cristina; Arattano, Massimo; Scavia, Claudio

    2013-04-01

    Rock-falls are one of the most common and hazardous phenomena occurring in mountainous areas. The formation of cracks in rocks is often accompanied by a sudden release of energy, which propagates in form of elastic waves and can be detected by a suitable transducer array. Therefore, geophones are among the most effective monitoring devices to investigate eventual precursors of rock-fall phenomena. However, the identification of an efficient procedure to forecast rock-fall occurrence in space and time is still an open challenge. In this study, we aim at developing an efficient procedure to locate microseismic sources relevant to cracking mechanisms, and thus gather indications on eventual precursors of rock-fall phenomena. Common seismic location tools usually implement homogeneous or multilayered velocity models but, in case of high slope gradients and heavily fractured rock masses, these simplifications may lead to errors on the correct estimation of the source location. Thus, we analyzed how the consideration of 3D material properties on the propagation medium may influence the location. In the framework of the Alcotra 2007-2013 Project MASSA (Medium And Small Size rock-fall hazard Assessment), a monitoring system composed by 8 triaxial geophones was installed in 2010 at the J.A. Carrel hut (3829 m a.s.l., Matterhorn, NW Italian Alps) and during the first year of operation the network recorded more than 600 natural events that exceeded a fixed threshold [1]. Despite the harsh environmental conditions of the study area, eighteen points distributed as uniformly as possible in space were selected for hammering. The artificial source dataset of known coordinates was used to constrain a 3D heterogeneous velocity model through a Simultaneous Iterative Reconstructive Technique. In order to mitigate the intrinsic uncertainties of the inversion procedure, bootstrapping was performed to extend the dataset and a statistical analysis was issued to improve the model

  3. Present-Day 3D Velocity Field of Eastern North America Based on Continuous GPS Observations

    NASA Astrophysics Data System (ADS)

    Goudarzi, Mohammad Ali; Cocard, Marc; Santerre, Rock

    2016-07-01

    The Saint Lawrence River valley in eastern Canada was studied using observations of continuously operating GPS (CGPS) stations. The area is one of the most seismically active regions in eastern North America characterized by many earthquakes, which is also subject to an ongoing glacial isostatic adjustment. We present the current three-dimensional velocity field of eastern North America obtained from more than 14 years (9 years on average) of data at 112 CGPS stations. Bernese GNSS and GITSA software were used for CGPS data processing and position time series analysis, respectively. The results show the counterclockwise rotation of the North American plate in the No-Net-Rotation model with the average of 16.8 ± 0.7 mm/year constrained to ITRF 2008. We also present an ongoing uplift model for the study region based on the present-day CGPS observations. The model shows uplift all over eastern Canada with the maximum rate of 13.7 ± 1.2 mm/year and subsidence to the south mainly over northern USA with a typical rate of -1 to -2 mm/year and the minimum value of -2.7 ± 1.4 mm/year. We compared our model with the rate of radial displacements from the ICE-5G model. Both models agree within 0.02 mm/year at the best stations; however, our model shows a systematic spatial tilt compared to ICE-5G. The misfits between two models amount to the maximum relative subsidence of -6.1 ± 1.1 mm/year to the east and maximum relative uplift of 5.9 ± 2.7 mm/year to the west. The intraplate horizontal velocities are radially outward from the centers of maximum uplift and are inward to the centers of maximum subsidence with the typical velocity of 1-1.6 ± 0.4 mm/year that is in agreement with the ICE-5G model to the first order.

  4. A Robust Method to Detect Zero Velocity for Improved 3D Personal Navigation Using Inertial Sensors

    PubMed Central

    Xu, Zhengyi; Wei, Jianming; Zhang, Bo; Yang, Weijun

    2015-01-01

    This paper proposes a robust zero velocity (ZV) detector algorithm to accurately calculate stationary periods in a gait cycle. The proposed algorithm adopts an effective gait cycle segmentation method and introduces a Bayesian network (BN) model based on the measurements of inertial sensors and kinesiology knowledge to infer the ZV period. During the detected ZV period, an Extended Kalman Filter (EKF) is used to estimate the error states and calibrate the position error. The experiments reveal that the removal rate of ZV false detections by the proposed method increases 80% compared with traditional method at high walking speed. Furthermore, based on the detected ZV, the Personal Inertial Navigation System (PINS) algorithm aided by EKF performs better, especially in the altitude aspect. PMID:25831086

  5. Resolving the 3D velocity field inside a Roughness Sublayer in a turbulent channel flow using HPIV

    NASA Astrophysics Data System (ADS)

    Talapatra, Siddharth; Katz, Joseph

    2010-11-01

    Microscopic holographic PIV is used to measure the 3D velocity field within the roughness sublayer of a turbulent channel flow at Reτ of 3400. Recording holograms through a rough surface is facilitated by matching the optical refractive index of the rough wall with that of the working fluid, a concentrated solution of NaI in water. The pyramidal roughness height is k=0.45mm, the sample volume size is 3.2x1.8x1.8mm^3, the long dimension being in the streamwise direction, and the wall-normal range is -0.333D grid to obtain vectors with a spacing of 60μm or 8.5 wall units. The data show that at y/k<0.5, there is a preferred channeling of the flow along paths that circumvent the pyramid crest lines. Planar vorticity distribution from different perspectives as well as 3D isosurfaces show that the near wall region is flooded by quasi-streamwise vortices that are aligned at shallow angles and have a typical streamwise extent of 1-2k.

  6. Near-wall 3D velocity measurements above biomimetic shark skin denticles using Digital In-line Holographic Microscopy

    NASA Astrophysics Data System (ADS)

    Toloui, Mostafa; Brajkovic, David; Hong, Jiarong

    2014-11-01

    Digital In-line Holography is employed to image 3D flow structures in the vicinity of a transparent rough surface consisting of closely packed biomimetic shark skin denticles as roughness elements. The 3D printed surface replicates the morphological features of real shark skin, and the denticles have a geometrical scale of 2 mm, i.e. 10 times of the real ones. In order to minimize optical aberrations near the fluid-roughness interface and enable flow measurements around denticles, the optical refractive index of the fluid medium is maintained the same as that of the denticle model in an index-matched flow facility using NaI solution as the working fluid. The experiment is conducted in a 1.2 m long test section with 50 mm × 50 mm cross section. The sampling volume is located in the downstream region of a shark skin replica of 12'' stretch where the turbulent flow is fully-developed and the transitional effect from smooth to the rough surface becomes negligible. Several instantaneous realizations of the 3D velocity field are obtained and are used to illustrate turbulent coherent structures induced by shark-skin denticles. This information will provide insights on the hydrodynamic function of shark's unique surface ornamentation.

  7. Constraints on the 3D shape of the ultra low shear velocity zone at the base of the mantle beneath the central Pacific

    NASA Astrophysics Data System (ADS)

    To, A.; Capdeville, Y.

    2011-12-01

    Prominent postcursors to S/Sdiff waves with delays as large as 26 s are observed in Northern America for Papua New Guinea events (To et al., 2011). The emergence of the postcursor is explained by placing a laterally localized ultra low shear velocity zone (ULSVZ, dVs/Vs<-25%) on the CMB, which is fully or partially covered by a broad and weak anomaly region (dVs/Vs~-5%). The ULSVZ is located approximately 900 km southwest of the projection of the Hawaiian hotspot onto the CMB. In the previous study, we limited our focus to an azimuthal range around 60 degrees from the source in Papua New Guinea, where the records show a relatively small azimuthal variation, suggesting a relatively small 3D effect there. The modelling was limited to 2D structure along the great circle plane, partly because of the sparse station distribution in Midwestern US at the time. In this study, we investigated data from USArray and further constrained the 3D shape of the ULSVZ. The postcursors to S/Sdiff waves are observed at 240 USArray stations for an event, which occurred near Papua New Guinea in 2010. The records from the large number of stations enabled us to conduct array analysis. First, we mapped the variation of incident azimuth and slowness of the secondary arrivals to the stations. In southern stations, which are located along the azimuth of approximately 60 degrees from the source, the postcursors arrive from the direction of the source. On the other hand, in northern stations, which are located at the azimuth of approximately 52 degrees from the source, the postcursors arrive from the azimuth of 5 to 10 degrees to the south with respect to the direction toward the source. Second, we compared the observed amplitude of the main S/Sdiff phase with synthetic waveforms created by Direct solution method (Kawai et al., 2006). The comparison shows that the amplitude of the main phase become very small at stations which are located approximately at the distance of 100 degrees and the

  8. 3D mechanical modeling of the GPS velocity field along the North Anatolian fault

    NASA Astrophysics Data System (ADS)

    Provost, Ann-Sophie; Chéry, Jean; Hassani, Riad

    2003-04-01

    The North Anatolian fault (NAF) extends over 1500 km in a complex tectonic setting. In this region of the eastern Mediterranean, collision of the Arabian, African and Eurasian plates resulted in creation of mountain ranges (i.e. Zagros, Caucasus) and the westward extrusion of the Anatolian block. In this study we investigate the effects of crustal rheology on the long-term displacement rate along the NAF. Heat flow and geodetic data are used to constrain our mechanical model, built with the three-dimensional finite element code ADELI. The fault motion occurs on a material discontinuity of the model which is controlled by a Coulomb-type friction. The rheology of the lithosphere is composed of a frictional upper crust and a viscoelastic lower crust. The lithosphere is supported by a hydrostatic pressure at its base (representing the asthenospheric mantle). We model the long-term deformation of the surroundings of the NAF by adjusting the effective fault friction and also the geometry of the surface fault trace. To do so, we used a frictional range of 0.0-0.2 for the fault, and a viscosity varying between 10 19 and 10 21 Pa s. One of the most striking results of our rheological tests is that the upper part of the fault is locked if the friction exceeds 0.2. By comparing our results with geodetic measurements [McClusky et al., J. Geophys. Res. B 105 (2000) 5695-5719] and tectonic observations, we have defined a realistic model in which the displacement rate on the NAF reaches ˜17 mm/yr for a viscosity of 10 19 Pa s and a fault friction of 0.05. This strongly suggests that the NAF is a weak fault like the San Andreas fault in California. Adding topography with its corresponding crustal root does not induce gravity flow of Anatolia. Rather, it has the counter-intuitive effect of decreasing the westward Anatolian escape. We find a poor agreement between our calculated velocity field and what is observed with GPS in the Marmara and the Aegean regions. We suspect that the

  9. 3D Anisotropic Velocity Tomography of a Water Saturated Rock under True-Triaxial Stress in the Laboratory

    NASA Astrophysics Data System (ADS)

    Ghofrani Tabari, M.; Goodfellow, S. D.; Nasseri, M. B.; Young, R.

    2013-12-01

    A cubic specimen of water saturated Fontainebleau Sandstone is tested in the laboratory under true-triaxial loading where three different principal stresses are applied under drained conditions. Due to the loading arrangement, closure and opening of the pre-existing cracks in the rock, as well as creation and growth of the aligned cracks cause elliptical anisotropy and distributed heterogeneities. A Geophysical Imaging Cell equipped with an Acoustic Emission monitoring system is employed to image velocity structure of the sample during the experiment through repeated transducer to transducer non-destructive ultrasonic surveys. Apparent P-wave velocities along the rock body are calculated in different directions and shown in stereonet plots which demonstrate an overall anisotropy of the sample. The apparent velocities in the main three orthogonal cubic directions are used as raw data for building a mean spatial distribution model of anisotropy ratios. This approach is based on the concept of semi-principal axes in an elliptical anisotropic model and appointing two ratios between the three orthogonal velocities in each of the cubic grid cells. The spatial distribution model of anisotropy ratios are used to calculate the anisotropic ray-path segment matrix elements (Gij). These contain segment lengths of the ith ray in the jth cell in three dimensions where, length of each ray in each cell is computed for one principal direction based on the dip and strike of the ray and these lengths differ from the ones in an isotropic G Matrix. 3D strain of the squeezed rock and the consequent geometrical deformation is also included in the ray-path segment matrix. A Singular Value Decomposition (SVD) method is used for inversion from the data space of apparent velocities to the model space of P-wave propagation velocities in the three principal directions. Finally, spatial variation and temporal evolution of induced damages in the rock, representing uniformly distributed or

  10. Quasiparticle spin relaxation with superconducting velocity-tunable state in GaAs(100) quantum wells in proximity to s -wave superconductor

    NASA Astrophysics Data System (ADS)

    Yu, T.; Wu, M. W.

    2016-11-01

    We investigate the quasiparticle spin relaxation with superconducting-velocity-tunable state in GaAs (100) quantum wells in proximity to an s -wave superconductor. We first present the influence of the supercurrent on the quasiparticle state in GaAs (100) quantum wells, which can be tuned by the superconducting velocity. Rich features such as the suppressed Cooper pairings, large quasiparticle density and nonmonotonically tunable momentum current can be realized by varying the superconducting velocity. In the degenerate regime, the quasiparticle Fermi surface is composed by two arcs, referred to as Fermi arcs, which are contributed by the electron- and holelike branches. The D'yakonov-Perel' spin relaxation is then explored, and intriguing physics is revealed when the Fermi arc emerges. Specifically, when the order parameter tends to zero, it is found that the branch-mixing scattering is forbidden in the quasielectron band. When the condensation process associated with the annihilation of the quasielectron and quasihole is slow, this indicates that the electron- and holelike Fermi arcs in the quasielectron band are independent. The open structure of the Fermi arc leads to the nonzero angular average of the effective magnetic field due to the spin-orbit coupling, which acts as an effective Zeeman field. This Zeeman field leads to spin oscillations even in the strong-scattering regime. Moreover, in the strong-scattering regime, we show that the open structure of the Fermi arc also leads to the insensitiveness of the spin relaxation to the momentum scattering, in contrast to the conventional motional narrowing situation. Nevertheless, with a finite order parameter, the branch-mixing scattering can be triggered, opening the interbranch spin relaxation channel, which is dominant in the strong-scattering regime. In contrast to the situation with an extremely small order parameter, due to the interbranch channel, the spin oscillations vanish and the spin relaxation

  11. A New Ionosphere Tomography Algorithm with Two-Grids Virtual Observations Constraints and 3D Velocity Profile

    NASA Astrophysics Data System (ADS)

    Kong, Jian; Yao, Yibin; Shum, Che-Kwan

    2014-05-01

    Due to the sparsity of world's GNSS stations and limitations of projection angles, GNSS-based ionosphere tomography is a typical ill-posed problem. There are two main ways to solve this problem. Firstly the joint inversion method combining multi-source data is one of the effective ways. Secondly using a priori or reference ionosphere models, e.g., IRI or GIM models, as the constraints to improve the state of normal equation is another effective approach. The traditional way for adding constraints with virtual observations can only solve the problem of sparse stations but the virtual observations still lack horizontal grid constraints therefore unable to fundamentally improve the near-singularity characteristic of the normal equation. In this paper, we impose a priori constraints by increasing the virtual observations in n-dimensional space, which can greatly reduce the condition number of the normal equation. Then after the inversion region is gridded, we can form a stable structure among the grids with loose constraints. We then further consider that the ionosphere indeed changes within certain temporal scale, e.g., two hours. In order to establish a more sophisticated and realistic ionosphere model and obtain the real time ionosphere electron density velocity (IEDV) information, we introduce the grid electron density velocity parameters, which can be estimated with electron density parameters simultaneously. The velocity parameters not only can enhance the temporal resolution of the ionosphere model thereby reflecting more elaborate structure (short-term disturbances) under ionosphere disturbances status, but also provide a new way for the real-time detection and prediction of ionosphere 3D changes. We applied the new algorithm to the GNSS data collected in Europe for tomography inversion for ionosphere electron density and velocity at 2-hour resolutions, which are consistent throughout the whole day variation. We then validate the resulting tomography model

  12. The 3-D strain patterns in Turkey using geodetic velocity fields from the RTK-CORS (TR) network

    NASA Astrophysics Data System (ADS)

    Kutoglu, Hakan Senol; Toker, Mustafa; Mekik, Cetin

    2016-03-01

    This study presents our use of GPS data to obtain and quantify the full continuous strain tensor using a 3-D velocity field in Turkey. In this study, GPS velocities improve the estimation of short-term strain tensor fields for determining the seismic hazard of Turkey. The tensorial analysis presents different aspects of deformation, such as the normal and shear strains, including their directions, the compressional and extensional strains. This analysis is appropriate for the characterizing the state of the current seismic deformation. GPS velocity data from continuous measurements (2009-2012) to estimate deformations were processed using the GAMIT/GLOBK software. Using high-rate GPS data from permanent 146 GNSS stations (RTK-CORS-TR network), the strain distribution was determined and interpolated using a biharmonic spline technique. We show the strain field patterns within axial and plane form at several critical locations, and discuss these results within the context of the seismic and tectonic deformation of Turkey. We conclude that the knowledge of the crustal strain patterns provides important information on the location of the main faults and strain accumulation for the hazard assessment. The results show an agreement between the seismic and tectonic strains confirming that there are active crustal deformations in Turkey.

  13. 3D tomographic reconstruction of the internal velocity field of an immiscible drop in a shear flow

    NASA Astrophysics Data System (ADS)

    Kerdraon, Paul; Dalziel, Stuart B.; Goldstein, Raymond E.; Landel, Julien R.; Peaudecerf, Francois J.

    2015-11-01

    We study experimentally the internal flow of a drop attached to a flat substrate and immersed in an immiscible shear flow. Transport inside the drop can play a crucial role in cleaning applications. Internal advection can enhance the mass transfer across the drop surface, thus increasing the cleaning rate. We used microlitre water-glycerol drops on a hydrophobic substrate. The drops were spherical and did not deform significantly under the shear flow. An oil phase of relative viscosity 0.01 to 1 was flowed over the drop. Typical Reynolds numbers inside the drops were of the order of 0.1 to 10. Using confocal microscopy, we performed 3D tomographic reconstruction of the flow field in the drop. The in-plane velocity field was measured using micro-PIV, and the third velocity component was computed from incompressibility. To our knowledge, this study gives the first experimental measurement of the three-dimensional internal velocity field of a drop in a shear flow. Numerical simulations and theoretical models published in the past 30 years predict a toroidal internal recirculation flow, for which the entire surface flows streamwise. However, our measurements reveal a qualitatively different picture with a two-lobed recirculation, featuring two stagnation points at the surface and a reverse surface flow closer to the substrate. This finding appears to be independent of Reynolds number and viscosity ratio in the ranges studied; we conjecture that the observed flow is due to the effect of surfactants at the drop surface.

  14. Petrophysical approach for S-wave velocity prediction based on brittleness index and total organic carbon of shale gas reservoir: A case study from Horn River Basin, Canada

    NASA Astrophysics Data System (ADS)

    Kim, Taeyoun; Hwang, Seho; Jang, Seonghyung

    2017-01-01

    When finding the "sweet spot" of a shale gas reservoir, it is essential to estimate the brittleness index (BI) and total organic carbon (TOC) of the formation. Particularly, the BI is one of the key factors in determining the crack propagation and crushing efficiency for hydraulic fracturing. There are several methods for estimating the BI of a formation, but most of them are empirical equations that are specific to particular rock types. We estimated the mineralogical BI based on elemental capture spectroscopy (ECS) log and elastic BI based on well log data, and we propose a new method for predicting S-wave velocity (VS) using mineralogical BI and elastic BI. The TOC is related to the gas content of shale gas reservoirs. Since it is difficult to perform core analysis for all intervals of shale gas reservoirs, we make empirical equations for the Horn River Basin, Canada, as well as TOC log using a linear relation between core-tested TOC and well log data. In addition, two empirical equations have been suggested for VS prediction based on density and gamma ray log used for TOC analysis. By applying the empirical equations proposed from the perspective of BI and TOC to another well log data and then comparing predicted VS log with real VS log, the validity of empirical equations suggested in this paper has been tested.

  15. Aftershock Observation of the 2014 South Napa Earthquake and Shallow S-wave Velocity Structure Obtained by Passive Surface Wave Method at Three Sites

    NASA Astrophysics Data System (ADS)

    Hayashi, K.; Roughley, C.; Craig, M. S.

    2014-12-01

    A M6.0 earthquake occurred in South Napa County on August 24, 2014. We recorded aftershocks and conducted S-wave velocity (VS) surveys using a passive surface method at three sites in Napa.On the day of the earthquake, we confirmed surface rupture for at least 5 km. Seismographs were deployed at three locations the day after the mainshock; on east side of Napa Valley (CSUEB-3), the west side (CSUEB-2), and at Stone Bridge School (CSUEB-1 SBS), which is located directly on the line of surface rupture (Fig. 1). The seismographs recorded continuous data for two weeks. At least 60 aftershocks with magnitudes between 1.0 and 3.9 were recorded. Preliminary analysis indicates a difference in local amplification of horizontal ground motion for 1-5 Hz, with amplitudes on the west side of Napa Valley larger than those on the east side. A passive surface wave survey using the two-station spatial autocorrelation (2ST-SPAC) method was conducted at each of the aftershock observation sites. At each site, one seismograph was established at a fixed location and recorded ambient noise for the duration of the survey. A second seismograph was placed at a series of different locations, with the distance from the fixed station ranging from 5 to 40 m. At each measurement location, ambient noise was recorded for intervals ranging from 5 to 20 minutes using a 10 ms sample rate, for a total of approximately one hour of data acquisition per site. The vertical component of ambient noise was used in the SPAC analysis to calculate phase velocity. Fig. 2 shows a VS profile at Stone Bridge School (CSUEB-1), which consists of two layers; the first with VS of about 150 m/sec and the second with VS of 400-500 m/sec. Depth to the second layer is about 20 m.

  16. A compact single-camera system for high-speed, simultaneous 3-D velocity and temperature measurements.

    SciTech Connect

    Lu, Louise; Sick, Volker; Frank, Jonathan H.

    2013-09-01

    The University of Michigan and Sandia National Laboratories collaborated on the initial development of a compact single-camera approach for simultaneously measuring 3-D gasphase velocity and temperature fields at high frame rates. A compact diagnostic tool is desired to enable investigations of flows with limited optical access, such as near-wall flows in an internal combustion engine. These in-cylinder flows play a crucial role in improving engine performance. Thermographic phosphors were proposed as flow and temperature tracers to extend the capabilities of a novel, compact 3D velocimetry diagnostic to include high-speed thermometry. Ratiometric measurements were performed using two spectral bands of laser-induced phosphorescence emission from BaMg2Al10O17:Eu (BAM) phosphors in a heated air flow to determine the optimal optical configuration for accurate temperature measurements. The originally planned multi-year research project ended prematurely after the first year due to the Sandia-sponsored student leaving the research group at the University of Michigan.

  17. Relationship Between Low-Velocity S-wave Anomalies, Asthenospheric Dynamics and Basaltic Volcanism in the Intraplate Setting of the Basin and Range, USA

    NASA Astrophysics Data System (ADS)

    Tibbetts, A. K.; Smith, E. I.; Conrad, C. P.; Lee, C.; Plank, T.; Yang, Y.

    2009-12-01

    Pliocene to Recent intraplate mafic volcanic rocks of the Basin and Range Province mostly formed by asthenospheric melting, as determined from calculated melting temperatures ranging from 1249-1521 degrees C. Here asthenosphere is defined by mantle rheology and temperature and not by geochemistry. The duration of melting in a volcanic field may be related to the size and shape of pockets of low velocity asthenosphere moving under the areas of volcanism. Seismic S-wave velocity profiles constrained by ambient noise and earthquake tomography of the mantle (Yang et al., 2008) show low velocity pockets, which may correspond to higher temperatures and/or higher water contents. The lack of wider scale volcanism in the Basin and Range despite large scale anomalies indicates that the anomalies are not the only cause of melting. The observed smaller scale magmatism can be explained by circulatory flow driven by the small scale structure of the anomalies causing localized melting within the anomalies. By applying an asthenospheric shear flow velocity of 0 cm/yr at the base of the lithosphere and 5 cm/yr east at depth (Silver & Holt 2002, Conrad et al., 2007), the distance the mantle has moved since the time of volcanism can be calculated for basalts of known age. Past positions of low-velocity anomalies in the asthenosphere combined with depths and temperatures of melting calculated using the silica-liquid geobarometer (Lee et al., 2009) were used to determine if a low velocity anomaly existed under an area of volcanism at the depth of melting and time of eruption. The data constraints used for calculating depths and temperatures of melting are dry, MgO > 7.5 wt.%, SiO2 > 44 wt.%, and Fe as 90% Fe2+. Depths and temperatures of melting were calculated for San Francisco in AZ; Amboy, Pisgah, Death Valley, Coso, Big Pine, Cima, Long Valley, in CA; Crater Flat, Lunar Crater, Reveille in NV; and Black Rock, Hurricane, Snow Canyon, UT; and others all of which have known ages. Ages

  18. Solar Wind Heating as Revealed from the Variation of 3D Ion Velocity Distributions across the Magnetic Reconnection Exhaust Region

    NASA Astrophysics Data System (ADS)

    He, J.

    2015-12-01

    Magnetic reconnection within current sheet has been regarded as one of the crucial dissipation and heating processes of coherent structures in the solar wind turbulence. Counter-streaming of ions is an important phenomenon in the reconnection exhaust region ranged from the ion diffusion region to the extended outflow region. It has been suggested by theoretical and numerical models that the ions are going to be picked up by the ejecting magnetic field and show larger T_perpendicular than T_parallel, if the guide field is strong enough (in other word, the shear angle is relatively low). The pick-up behavior seems to favor the heating of heavy ions with high mass-to-charge ratio, since the high M/Q ions have larger gyro-period/transit-time and tend to be non-adiabatic more easily. The above statements from theoretical models have not been thoroughly testified in the solar wind observations, though the changes in total temperature and 1D reduced velocity distribution function had been studied. Until now, it remains unclear about the difference of full 3D velocity distribution for the proton and helium ions between the upstream and the exhaust regions. Here, we will analyze the plasma measurement data from WIND/3DP to explore and compare the parallel and perpendicular heating effect of different species of ions. As a preliminary result, the proton is found to show bi-directional streams in its velocity distribution in some reconnection exhaust regions. The thermalization of the counter-streaming protons will be presented. The relation between proton T_parallel/T_perpendicular and guide field strength (or shear angle) will be studied. The velocity distributions of helium ions will be illustrated, which shows the difference of heating effect between different M/Q ratios.

  19. Seismicity patterns along the Ecuadorian subduction zone: new constraints from earthquake location in a 3-D a priori velocity model

    NASA Astrophysics Data System (ADS)

    Font, Yvonne; Segovia, Monica; Vaca, Sandro; Theunissen, Thomas

    2013-04-01

    To improve earthquake location, we create a 3-D a priori P-wave velocity model (3-DVM) that approximates the large velocity variations of the Ecuadorian subduction system. The 3-DVM is constructed from the integration of geophysical and geological data that depend on the structural geometry and velocity properties of the crust and the upper mantle. In addition, specific station selection is carried out to compensate for the high station density on the Andean Chain. 3-D synthetic experiments are then designed to evaluate the network capacity to recover the event position using only P arrivals and the MAXI technique. Three synthetic earthquake location experiments are proposed: (1) noise-free and (2) noisy arrivals used in the 3-DVM, and (3) noise-free arrivals used in a 1-DVM. Synthetic results indicate that, under the best conditions (exact arrival data set and 3-DVM), the spatiotemporal configuration of the Ecuadorian network can accurately locate 70 per cent of events in the frontal part of the subduction zone (average azimuthal gap is 289° ± 44°). Noisy P arrivals (up to ± 0.3 s) can accurately located 50 per cent of earthquakes. Processing earthquake location within a 1-DVM almost never allows accurate hypocentre position for offshore earthquakes (15 per cent), which highlights the role of using a 3-DVM in subduction zone. For the application to real data, the seismicity distribution from the 3-D-MAXI catalogue is also compared to the determinations obtained in a 1-D-layered VM. In addition to good-quality location uncertainties, the clustering and the depth distribution confirm the 3-D-MAXI catalogue reliability. The pattern of the seismicity distribution (a 13 yr record during the inter-seismic period of the seismic cycle) is compared to the pattern of rupture zone and asperity of the Mw = 7.9 1942 and the Mw = 7.7 1958 events (the Mw = 8.8 1906 asperity patch is not defined). We observe that the nucleation of 1942, 1958 and 1906 events coincides with

  20. Hypocenter relocation using a fast grid search method and a 3-D seismic velocity model for the Sumatra region

    SciTech Connect

    Nugroho, Hendro; Widiyantoro, Sri; Nugraha, Andri Dian

    2013-09-09

    Determination of earthquake hypocenter in Indonesia conducted by the Meteorological, Climatological, and Geophysical Agency (MCGA) has still used a 1-D seismic velocity model. In this research, we have applied a Fast Grid Search (FGM) method and a 3-D velocity model resulting from tomographic imaging to relocate earthquakes in the Sumatran region. The data were taken from the MCGA data catalog from 2009 to 2011 comprising of subduction zone and on land fault earthquakes with magnitude greater than 4 Mw. Our preliminary results show some significant changes in the depths of the relocated earthquakes which are in general deeper than the depths of hypocenters from the MCGA data catalog. The residual times resulting from the relocation process are smaller than those prior to the relocation. Encouraged by these results, we will continue to conduct hypocenter relocation for all events from the MCGA data catalog periodically in order to produce a new data catalog with good quality. We hope that the new data catalog will be useful for further studies.

  1. Zemmouri earthquake rupture zone (Mw 6.8, Algeria): Aftershocks sequence relocation and 3D velocity model

    NASA Astrophysics Data System (ADS)

    Ayadi, A.; Dorbath, C.; Ousadou, F.; Maouche, S.; Chikh, M.; Bounif, M. A.; Meghraoui, M.

    2008-09-01

    We analyze the aftershocks sequence of the Zemmouri thrust faulting earthquake (21 May 2003, Mw 6.8) located east of Algiers in the Tell Atlas. The seismic sequence located during ˜2 months following the mainshock is made of more than 1500 earthquakes and extends NE-SW along a ˜60-km fault rupture zone crossing the coastline. The earthquake relocation was performed using handpicked P and S phases located with the tomoDD in a detailed 3D velocity structure of the epicentral area. Contrasts between velocity patches seem to correlate with contacts between granitic-volcanic basement rocks and the sedimentary formation of the eastern Mitidja basin. The aftershock sequence exhibits at least three seismic clouds and a well-defined SE-dipping main fault geometry that reflects the complex rupture. The distribution of seismic events presents a clear contrast between a dense SW zone and a NE zone with scattered aftershocks. We observe that the mainshock locates between the SW and NE seismic zones; it also lies at the NNS-SSE contact that separates a basement block to the east and sedimentary formations to the west. The aftershock distribution also suggests fault bifurcation at the SW end of the fault rupture, with a 20-km-long ˜N 100° trending seismic cluster, with a vertical fault geometry parallel to the coastline juxtaposed. Another aftershock cloud may correspond to 75° SE dipping fault. The fault geometry and related SW branches may illustrate the interference between pre-existing fault structures and the SW rupture propagation. The rupture zone, related kinematics, and velocity contrasts obtained from the aftershocks distribution are in agreement with the coastal uplift and reflect the characteristics of an active zone controlled by convergent movements at a plate boundary.

  2. S-wave velocities and anisotropy of typical rocks from Yunkai metamorphic complex and constraints on the composition of the crust beneath Southern China

    NASA Astrophysics Data System (ADS)

    Ji, Shaocheng; Wang, Qian; Shao, Tongbin; Endo, Hiroto; Michibayashi, Katsuyoshi; Salisbury, Matthew H.

    2016-08-01

    In order to constrain the interpretation of seismic data from receiver functions and deep profiles of the crust beneath southern China (Cathaysia and Yangtze blocks), we have measured S-wave velocities (Vs) and splitting as a function of hydrostatic confining pressure up to 650 MPa for 22 representative samples (i.e., granite, diorite, felsic gneiss and mylonite, amphibolite, schist, and marble) from the Yunkai metamorphic complex (China) that represent the crystalline basement beneath the region. The experimental data were combined with electron backscattering diffraction (EBSD) analysis of rock-forming minerals to constrain variations of Vp/Vs ratios and understand the origin of seismic anisotropy. The crusts beneath the Yangtze and Cathaysia blocks have different average thicknesses (H = 35.4 ± 6.3 km and 29.8 ± 1.8 km, respectively) but display almost the same Vp/Vs values (1.73 ± 0.08 and 1.74 ± 0.04, respectively). These ratios correspond to an average of bimodally distributed granitic and gabbroic lithologies which are dominant, respectively, in the upper and lower crusts, instead a homogeneous andesitic composition of the overall crust. Positive and negative correlations between H and Vp/Vs occur in west and east parts of southern China, respectively. The negative correlation indicates basaltic underplating from a partially molten mantle wedge above the subducting Pacific plate into the southern China crust, whereas the positive correlation implies that much larger thinning strain has taken place in the high temperature mafic lower crust (high temperature) than in the low temperature felsic upper crust during Mesozoic-Cenozoic tectonic extension.

  3. Constructing a 3D Crustal Model Across the Entire Contiguous US Using Broadband Rayleigh Wave Phase Velocity and Ellipticity Measurements

    NASA Astrophysics Data System (ADS)

    Lin, F. C.; Schmandt, B.

    2015-12-01

    Imaging the crust and lithosphere structure beneath North America is one of the primary targets for the NSF-funded EarthScope project. In this study, we apply the recently developed ambient noise and surface wave tomography methods to construct a detailed 3D crustal model across the entire contiguous US using USArray data between January 2007 and May 2015. By using both Rayleigh wave phase velocity and ellipticity measurements between 8 and 100 sec period, the shear velocity structure can be well resolved within the five crustal layers we modeled: three upper crust, one middle crust, and one lower crust. Clear correlations are observed between the resolved velocity anomalies and known geological features at all depths. In the uppermost crust, slow Vs anomalies are observed within major sedimentary environments such as the Williston Basin, Denver Basin, and Mississippi embayment, and fast Vs anomalies are observed in environments with deeply exhumed bedrock outcrops at the surface including the Laurentian Highlands, Ouachita-Ozark Interior Highlands, and Appalachian Highlands. In the deeper upper crust, slow anomalies are observed in deep sedimentary basins such as the Green River Basin, Appalachian Basin, Southern Oklahoma Aulacogen, and areas surrounding the Gulf of Mexico. Fast anomalies, on the other hand, are observed in the Colorado Plateau, within the Great Plains between the Front Ranges and Midcontinental Rift, and east of the Appalachian Mountains. At this depth, the Midcontinental Rift and Grenville Front clearly correlate well with various velocity structure boundaries. In the middle crust, slow anomalies are mostly observed in the tectonically active areas in the western US, but relatively slow anomalies are also observed southeast of the Precambrian Rift Margins. At this depth, fast anomalies are observed beneath various deep sedimentary basins such as the Southern Oklahoma Aulacogen, Appalachian Basin, and Central Valley. In the lower crust, a clear

  4. Imaging Magma Under St. Helens (iMUSH): Details of passive-source seismic deployment and preliminary 3-D velocity structure

    NASA Astrophysics Data System (ADS)

    Ulberg, C. W.; Creager, K. C.; Moran, S. C.; Abers, G. A.; Denlinger, R. P.; Hotovec-Ellis, A. J.; Vidale, J. E.; Kiser, E.; Levander, A.; Schultz, A.

    2014-12-01

    The imaging Magma Under St. Helens (iMUSH) experiment aims to delineate the extent of the magmatic system beneath Mount St. Helens (MSH) in Washington State. The experiment involves active- and passive-source seismology, magnetotellurics, and geochemistry/petrology. Seventy passive-source broadband seismometers were deployed in a 100-km-diameter array centered on MSH, with an average spacing of 10 km, and a planned duration of two years. The deployment over two weeks in June 2014 involved a group of 18 people split into 6 teams. Approximately half of the seismic stations have aircell batteries and/or pole-mounted solar panels in order to maintain power through deep snow at higher elevations during the winter months. Data will be retrieved 2-4 times a year throughout the duration of the experiment. The first service run performed in mid-July 2014 had a 98.4% data recovery. This is one of the largest wide-aperture two-dimensional arrays covering a volcano anywhere. The active-source portion of the experiment successfully set off 23 shots in late-July 2014. These were recorded clearly at permanent stations run by the Pacific Northwest Seismic Network up to 200 km away, and are expected to be well-recorded on many of the 70 broadband seismometers in addition to the 2500 Reftek "Texans" deployed temporarily for this purpose. For the 2-4 weeks of broadband data collected in July, local earthquakes down to magnitude 0 are recorded across the array, with clear P- and S- arrivals. Earthquakes of this size occur daily within 50 km of MSH. We are keeping a careful catalog of all activity in the region for the duration of the iMUSH experiment. We will pick P- and S-wave travel times at the 70 broadband stations from local earthquakes and active shots, for available data from between June and October 2014. We will also use a tomographic code (Preston et al, 2003, Science) to invert the travel times to obtain preliminary earthquake location and 3-D velocity structure.

  5. Velocity Measurement in Carotid Artery: Quantitative Comparison of Time-Resolved 3D Phase-Contrast MRI and Image-based Computational Fluid Dynamics

    PubMed Central

    Sarrami-Foroushani, Ali; Nasr Esfahany, Mohsen; Nasiraei Moghaddam, Abbas; Saligheh Rad, Hamidreza; Firouznia, Kavous; Shakiba, Madjid; Ghanaati, Hossein; Wilkinson, Iain David; Frangi, Alejandro Federico

    2015-01-01

    Background: Understanding hemodynamic environment in vessels is important for realizing the mechanisms leading to vascular pathologies. Objectives: Three-dimensional velocity vector field in carotid bifurcation is visualized using TR 3D phase-contrast magnetic resonance imaging (TR 3D PC MRI) and computational fluid dynamics (CFD). This study aimed to present a qualitative and quantitative comparison of the velocity vector field obtained by each technique. Subjects and Methods: MR imaging was performed on a 30-year old male normal subject. TR 3D PC MRI was performed on a 3 T scanner to measure velocity in carotid bifurcation. 3D anatomical model for CFD was created using images obtained from time-of-flight MR angiography. Velocity vector field in carotid bifurcation was predicted using CFD and PC MRI techniques. A statistical analysis was performed to assess the agreement between the two methods. Results: Although the main flow patterns were the same for the both techniques, CFD showed a greater resolution in mapping the secondary and circulating flows. Overall root mean square (RMS) errors for all the corresponding data points in PC MRI and CFD were 14.27% in peak systole and 12.91% in end diastole relative to maximum velocity measured at each cardiac phase. Bland-Altman plots showed a very good agreement between the two techniques. However, this study was not aimed to validate any of methods, instead, the consistency was assessed to accentuate the similarities and differences between Time-resolved PC MRI and CFD. Conclusion: Both techniques provided quantitatively consistent results of in vivo velocity vector fields in right internal carotid artery (RCA). PC MRI represented a good estimation of main flow patterns inside the vasculature, which seems to be acceptable for clinical use. However, limitations of each technique should be considered while interpreting results. PMID:26793288

  6. 3D crustal seismic velocity model for the Gulf of Cadiz and adjacent areas (SW Iberia margin) based on seismic reflection and refraction profiles

    NASA Astrophysics Data System (ADS)

    Lozano, Lucía; Cantavella, Juan Vicente; Barco, Jaime; Carranza, Marta; Burforn, Elisa

    2016-04-01

    The Atlantic margin of the SW Iberian Peninsula and northern Morocco has been subject of study during the last 30 years. Many seismic reflection and refraction profiles have been carried out offshore, providing detailed information about the crustal structure of the main seafloor tectonic domains in the region, from the South Portuguese Zone and the Gulf of Cadiz to the Abyssal Plains and the Josephine Seamount. The interest to obtain a detailed and realistic velocity model for this area, integrating the available data from these studies, is clear, mainly to improve real-time earthquake hypocentral location and for tsunami and earthquake early warning. Since currently real-time seismic location tools allow the implementation of 3D velocity models, we aim to generate a full 3D crustal model. For this purpose we have reviewed more than 50 profiles obtained in different seismic surveys, from 1980 to 2008. Data from the most relevant and reliable 2D seismic velocity published profiles were retrieved. We first generated a Moho depth map of the studied area (latitude 32°N - 41°N and longitude 15°W - 5°W) by extracting Moho depths along each digitized profile with a 10 km spacing, and then interpolating this dataset using ordinary kriging method and generating the contour isodepth map. Then, a 3D crustal velocity model has been obtained. Selected vertical sections at different distances along each profile were considered to retrieve P-wave velocity values at each interface in order to reproduce the geometry and the velocity gradient within each layer. A double linear interpolation, both in distance and depth, with sampling rates of 10 km and 1 km respectively, was carried out to generate a (latitude, longitude, depth, velocity) matrix. This database of all the profiles was interpolated to obtain the P-wave velocity distribution map every kilometer of depth. The new 3D velocity model has been integrated in NonLinLoc location program to relocate several representative

  7. Teleseismic S wave microseisms.

    PubMed

    Nishida, Kiwamu; Takagi, Ryota

    2016-08-26

    Although observations of microseisms excited by ocean swells were firmly established in the 1940s, the source locations remain difficult to track. Delineation of the source locations and energy partition of the seismic wave components are key to understanding the excitation mechanisms. Using a seismic array in Japan, we observed both P and S wave microseisms excited by a severe distant storm in the Atlantic Ocean. Although nonlinear forcing of an ocean swell with a one-dimensional Earth model can explain P waves and vertically polarized S waves (SV waves), it cannot explain horizontally polarized S waves (SH waves). The precise source locations may provide a new catalog for exploring Earth's interior.

  8. Earthquake relocation using a 3D a-priori geological velocity model from the western Alps to Corsica: Implication for seismic hazard

    NASA Astrophysics Data System (ADS)

    Béthoux, Nicole; Theunissen, Thomas; Beslier, Marie-Odile; Font, Yvonne; Thouvenot, François; Dessa, Jean-Xavier; Simon, Soazig; Courrioux, Gabriel; Guillen, Antonio

    2016-02-01

    The region between the inner zones of the Alps and Corsica juxtaposes an overthickened crust to an oceanic domain, which makes difficult to ascertain the focal depth of seismic events using routine location codes and average 1D velocity models. The aim of this article is to show that, even with a rather lose monitoring network, accurate routine locations can be achieved by using realistic 3D modelling and advanced location techniques. Previous earthquake tomography studies cover the whole region with spatial resolutions of several tens of kilometres on land, but they fail to resolve the marine domain due to the absence of station coverage and sparse seismicity. To overcome these limitations, we first construct a 3D a-priori P and S velocity model integrating known geophysical and geological information. Significant progress has been achieved in the 3D numerical modelling of complex geological structures by the development of dedicated softwares (e.g. 3D GeoModeller), capable at once of elaborating a 3D structural model from geological and geophysical constraints and, possibly, of refining it by inversion processes (Calcagno et al., 2008). Then, we build an arrival-time catalogue of 1500 events recorded from 2000 to 2011. Hypocentres are then located in this model using a numerical code based on the maximum intersection method (Font et al., 2004), updated by Theunissen et al. (2012), as well as another 3D location technique, the NonLinLoc software (Lomax and Curtis, 2001). The reduction of arrival-time residuals and uncertainties (dh, dz) with respect to classical 1D locations demonstrates the improved accuracy allowed by our approach and confirms the coherence of the 3D geological model built and used in this study. Our results are also compared with previous works that benefitted from the installation of dense temporary networks surrounding the studied epicentre area. The resulting 3D location catalogue allows us to improve the regional seismic hazard assessment

  9. Crustal high-velocity anomaly at the East European Craton margin in SE Poland (TESZ) modelled by 3-D seismic tomography of refracted and reflected arrivals

    NASA Astrophysics Data System (ADS)

    Środa, Piotr; Dec, Monika

    2016-04-01

    The area of Trans-European Suture Zone in SE Poland represents a contact of major tectonic units of different consolidation age - from the Precambrian East European Craton, through Palaeozoic West European Platform to Cenozoic Carpathian orogen. The region was built by several phases of crustal accretion, which resulted in a complex collage of tectonic blocks. In 2000, this region was studied by several seismic wide-angle profiles of CELEBRATION 2000 experiment, providing a dense coverage of seismic data in SE Poland and allowing for detailed investigations of the crustal structure and properties in this area. Beneath the marginal part of the EEC, the 2-D modelling of in-line data form several CELEBRATION profiles revealed a prominent high P-wave velocity anomaly in the upper crust, with Vp of 6.7-7.1 km/s, starting at 10-16 km depth (e.g., Środa et al., 2006). Anomalously high velocities are observed in the area located approximately beneath Lublin trough, to the NE of Teisseyre-Tornquist Zone. Based on 3-D tomography of first arrivals of in- and off-line CELEBRATION 2000 recordings (Malinowski et al., 2008), elevated velocities are also reported in the same area and seem to continue to the SW, off the craton margin. Gravimetric modelling also revealed anomalously high density in the same region at similar depths. High seismic velocities and densities are interpreted as indicative for a pronounced mafic intrusion, possibly related to extensional processes at the EEC margin. Previous 3-D models of the high-velocity intrusion were based on first arrivals (crustal refractions) only. In this study, also off-line reflections (not modelled up to now) are used, in order to enlarge the data set and to better constrain the geometry and properties of the velocity anomaly. A code for 3-D joint tomographic inversion of refracted and reflected arrivals, with model parametrization allowing for velocity discontinuities was used (Rawlinson, 2007). With this approach, besides the

  10. A 3-D shear velocity model of the southern North America and the Caribbean plates from ambient noise and earthquake tomography

    NASA Astrophysics Data System (ADS)

    Gaite, B.; Villaseñor, A.; Iglesias, A.; Herraiz, M.; Jiménez-Munt, I.

    2014-10-01

    We use group velocities from earthquake tomography together with group and phase velocities from ambient noise tomography (ANT) of Rayleigh-waves to invert for the 3-D shear-wave velocity structure (5-70 km) of the Caribbean (CAR) and southern North American (NAM) plates. The lithospheric model proposed offers a complete image of the crust and uppermost-mantle with imprints of the tectonic evolution. One of the most striking features inferred is the main role of the Ouachita-Marathon-Sonora orogeny front on the crustal seismic structure of NAM plate. A new imaged feature is the low crustal velocities along USA-Mexico border. The model also shows a break of the E-W mantle velocity dichotomy of the NAM and CAR plates beneath the Isthmus of Tehuantepec and Yucatan Block. High upper-mantle velocities along the Mesoamerican Subduction Zone coincide with inactive volcanic areas while the lowest velocities correspond to active volcanic arcs and thin lithospheric mantle regions.

  11. From the Alpine region to the Central Apennines (Italy): 3d upper lithospheric P-velocity model with controlled source seismology data

    NASA Astrophysics Data System (ADS)

    di Stefano, R.; Tondi, R.; de Luca, L.; Lippitsch, R.; Sandoval, S.; Kissling, E.

    2003-04-01

    The complex lithosphere structure of the Italian region leads to difficulties in uniquely interpreting the results obtained with geophysical investigation methods. Relating to P waves velocity models, the geometry of the moho is the main first order structure influencing the interpretation of controlled source seismology (CSS) profile data and results from local earthquake tomography (LET). Moreover, the crustal structures complexities, though poorly resolved by teleseismic tomography, strongly distort teleseismic wave fronts and thus influence teleseismic traveltimes. In 1996 a method was developed by F. Waldhauser to determine the 3D topography and lateral continuity of seismic interfaces using 2D-derived controlled-source seismic reflector data. This method has been successfully applied to retrieve the moho geometry in the complex Alpine region with the aim to obtain the simplest possible 3D structure consistent with all reflector data and error estimates. For the Alpine region a 3D crustal P-wave velocity model has been thus developed from comparative use of published information from active and passive sources surveys. Here we present the extension of this map to the Italian peninsula to include Northern and Central Apennines. Information from the CROP project and from other CSS experiments performed in the past 40 years, both on land and offshore, has been included to cover the whole area. The first order features of Adriatic and Tyrrhenian moho have been recovered and a Vp crustal velocity model has been produced. For the Northern Apennines we compare the newly derived crustal model with the 3D structure of the crust obtained by the inversion of P-wave first arrivals picked on the CSS data, and of gravity data collected on land and off-shore (see Tondi et al., session SM3).

  12. Crustal and upper mantle 3D shear wave velocity structure of the High Lava Plains, Oregon, determined from ambient noise tomography

    NASA Astrophysics Data System (ADS)

    Hanson-Hedgecock, S.; Wagner, L.; Fouch, M. J.; James, D. E.

    2011-12-01

    We present the results of inversions for 3D shear velocity structure of the crust and uppermost mantle beneath the High Lava Plains, Oregon using data from ~300 broadband stations of the High Lava Plains seismic experiment and the EarthScope/USArray Transportable Array (TA). The High Lava Plains (HLP) is a WNW progressive silicic volcanism, initiated ~14.5 Ma near the Owyhee Plateau and is currently active at the Newberry caldera. The Yellowstone Snake River Plain (YSRP) volcanic track is temporally contemporaneous with the HLP, but trends to the northeast, parallel to North American plate motion. The cause of volcanism along the HLP is debated and has been variously attributed to Basin and Range extension, back-arc extension, rollback of the subducting Juan de Fuca plate, and an intra-continental hotspot/plume source. Additionally the relationship between the HLP, YSRP, and Columbia River Basalts (CRB), the three major post-17Ma intracontinental volcanic provinces of the Pacific Northwest, is not well understood. The 3D shear velocity structure of the crust and uppermost mantle to ~65km depth is determined from fundamental mode Rayleigh wave ambient noise phase velocity maps at periods up to 40s. The use of ambient noise tomography with the dense station spacing of the combined High Lava Plains seismic experiment and the EarthScope/USArray Transportable Array (TA) datasets allows the shallow structure of the High Lava Plains to be imaged in finer detail than previous ANT studies that focused on the entire western United States. In the crust, low velocities in central Oregon are observed in association with the Brothers Fault Zone, Jordan and Diamond Craters and Steens Mountain regions in addition to the strong low velocity zone associated with the Cascades to the west. To the east of the HLP, low velocities are observed to about 10km depth in the western SRP. In the eastern SRP we observe a shallow veneer of low velocities underlain by a ~10km thick high velocity

  13. Regional 3D Numerical Modeling of the Lithosphere-Mantle System: Implications for Continental Rift-Parallel Surface Velocities

    NASA Astrophysics Data System (ADS)

    Stamps, S.; Bangerth, W.; Hager, B. H.

    2014-12-01

    The East African Rift System (EARS) is an active divergent plate boundary with slow, approximately E-W extension rates ranging from <1-6 mm/yr. Previous work using thin-sheet modeling indicates lithospheric buoyancy dominates the force balance driving large-scale Nubia-Somalia divergence, however GPS observations within the Western Branch of the EARS show along-rift motions that contradict this simple model. Here, we test the role of mantle flow at the rift-scale using our new, regional 3D numerical model based on the open-source code ASPECT. We define a thermal lithosphere with thicknesses that are systematically changed for generic models or based on geophysical constraints in the Western branch (e.g. melting depths, xenoliths, seismic tomography). Preliminary results suggest existing variations in lithospheric thicknesses along-rift in the Western Branch can drive upper mantle flow that is consistent with geodetic observations.

  14. A Global 3D P-Velocity Model of the Earth’s Crust and Mantle for Improved Event Location

    DTIC Science & Technology

    2011-09-01

    locations were based on the ak135 model (Kennett et al., 1995). This shifting of locations tends to occur mostly along subduction zones , where the...features, many structural features present themselves. Clearly visible in the figures are subduction zones , mid-ocean ridges, slower velocities in...produced. Colors are percent change from the ak135 model. Clearly visible are tectonic features such as mid-ocean ridges, subduction zones , and large

  15. The Updated LLNL-G3D Global P-Wave Velocity Model and Its Performance in Seismic Event Location

    DTIC Science & Technology

    2011-09-01

    in our previous reports) and sharp details of subducted slabs around the world. Based on preliminary relocation tests, using LLNL-G3Dv2 travel-time...details of subducted slabs around the world. Based on preliminary relocation tests, using LLNL-G3Dv2 travel-time predictions typically reduces...simultaneously. In addition, sensitivity is spread across broad depth zones and/or multiple model units to mitigate the issue of path-velocity

  16. Effect of a low-velocity sedimentary cover on the 3-D velocity models derived from inversion of local arrival times. An example from the New Madrid seismic zone.

    NASA Astrophysics Data System (ADS)

    Pujol, J. M.; Chiu, J. M.

    2014-12-01

    When applying seismic tomography to local arrival times from an area with a low-velocity sedimentary cover, the effect of the sediments on travel times should be taken into account. If that is not done, the resulting velocity model(s) cannot be assumed to be correct. This fairly obvious statement has been challenged recently by Powell et al. (JGR, 2010), who claimed that the sediments that cover the New Madrid seismic zone (NMSZ, central United States) can be ignored. This claim is examined here and shown to be incorrect. The NMSZ is covered by low-velocity, poorly consolidated sediments (Vp=1.8 km/s, Vs=3), which are underlain by Paleozoic rocks of much higher velocity. In the central NMSZ the sediment thickness varies between about 0.1 and 0.7 km. The JHD analysis of the data collected in that area by a portable network (PANDA) showed that the P- and S-wave station corrections spanned large ranges (0.35 and 0.63 s, respectively, Pujol et al., Eng. Geol., 1997). This study also showed that a Vp/Vs of 3 for the sediments would be too high if the lateral velocity variations were confined to the sedimentary cover. Here we generate synthetic traveltimes for a model with a sedimentary cover having variable depth (as determined from boreholes) underlain by the high-velocity layers in the 1-D model used for the JHD analysis. The synthetic data were generated for the station and event distributions corresponding to the Panda data. The tomographic inversion of the synthetic times produces spurious anomalies in Vp, Vs, and Vp/Vs, from the surface to a depth of 10 km. In addition, the events are mislocated in depth, with errors between 0 and 1 km for most of them. These results should dispel the notion that the effect of the unconsolidated sediments can be ignored. On the other hand, the inversion of the actual Panda data results in velocity anomalies similar to the synthetic anomalies, although larger, which is consistent with the conclusions of Pujol et al. (1997

  17. Waveform inversion for 3-D S-velocity structure of D'' beneath the Northern Pacific: possible evidence for a remnant slab and a passive plume

    NASA Astrophysics Data System (ADS)

    Suzuki, Yuki; Kawai, Kenji; Geller, Robert J.; Borgeaud, Anselme F. E.; Konishi, Kensuke

    2016-12-01

    We conduct waveform inversion to infer the three-dimensional (3-D) S-velocity structure in the lowermost 400 km of the mantle (the D'' region) beneath the Northern Pacific region. Our dataset consists of about 20,000 transverse component broadband body-wave seismograms observed at North American stations for 131 intermediate and deep earthquakes which occurred beneath the western Pacific subduction region. We use S, ScS, and other phases that arrive between them. Resolution tests indicate that our methods and dataset can resolve the velocity structure in the target region with a horizontal scale of about 150 km and a vertical scale of about 50 km. The 3-D S-velocity model obtained in this study shows three prominent features: (1) prominent sheet-like lateral high-velocity anomalies up to ˜3% faster than the Preliminary Reference Earth Model (PREM) with a thickness of ˜200 km, whose lower boundary is ˜150 km above the core-mantle boundary (CMB). (2) A prominent low-velocity anomaly block located to the west of the Kamchatka peninsula, which is ˜2.5% slower than PREM, immediately above the CMB beneath the high-velocity anomalies. (3) A relatively thin (˜300 km) low-velocity structure continuous from the low-velocity anomaly "(2)" to at least 400 km above the CMB. We also detect a continuous low-velocity anomaly from the east of the Kamchatka peninsula at an altitude of 50 km above the CMB to the far east of the Kuril islands at an altitude of 400 km above the CMB. We interpret these features respectively as: (1) remnants of slab material where the bridgmanite to Mg-post-perovskite phase transition may have occurred within the slab, (2, 3) large amounts of hot and less dense materials beneath the cold Kula or Pacific slab remnants just above the CMB which ascend and form a passive plume upwelling at the edge of the slab remnants.[Figure not available: see fulltext.

  18. A high resolution 3D velocity model beneath the Tokyo Metropolitan area by MeSO-net

    NASA Astrophysics Data System (ADS)

    Nakagawa, S.; Sakai, S.; Honda, R.; Kimura, H.; Hirata, N.

    2015-12-01

    Beneath the Tokyo metropolitan area, the Philippine Sea Plate (PSP) subducts and causes devastating mega-thrust earthquakes, such as the 1703 Genroku earthquake (M8.0) and the 1923 Kanto earthquake (M7.9). An M7 or greater (M7+) earthquake in this area at present has high potential to produce devastating serious loss of life and property with even greater global economic repercussions. The Central Disaster Management Council of Japan estimates that an M7+ earthquake will cause 23,000 fatalities and 95 trillion yen (about 1 trillion US$) economic loss. We have launched the Special Project for Reducing Vulnerability for Urban Mega Earthquake Disasters in collaboration with scientists, engineers, and social-scientists in nationwide institutions since 2012. We analyze data from the dense seismic array called Metropolitan Seismic Observation network (MeSO-net), which has 296 seismic stations with spacing of 5 km (Sakai and Hirata, 2009; Kasahara et al., 2009). We applied the double-difference tomography method (Zhang and Thurber, 2003) and estimated the velocity structure and the upper boundary of PSP (Nakagawa et al., 2010). The 2011 Tohoku-oki earthquake (M9.0) has activated seismicity also in Kanto region, providing better coverage of ray paths for tomographic analysis. We obtain much higher resolution velocity models from whole dataset observed by MeSO-net between 2008 and 2015. A detailed image of tomograms shows that PSP contacts Pacific plate at a depth of 50 km beneath northern Tokyo bay. A variation of velocity along the oceanic crust suggests dehydration reaction to produce seismicity in a slab, which may related to the M7+ earthquake. Acknowledgement: This study was supported by the Special Project for Reducing Vulnerability for Urban Mega Earthquake Disasters of MEXT, Japan and the Earthquake Research Institute cooperative research program.

  19. Isotropic photon drag: Analytic expressions for velocity (3D) and position (1D) with applications to blackbody friction

    NASA Astrophysics Data System (ADS)

    West, Joseph

    2014-03-01

    The motion of objects traveling at relativistic speeds and subject only to isotropic photon drag (blackbody friction as a special case) is modeled. The objects are assumed to be perfectly absorbing. Analytic expressions for velocity and position as a function of time for objects subject to photon drag are obtained for the case in which the photons are constrained to one-dimensional motion. If the object is also assumed to be a perfect emitter of energy, analytic expressions are found for time as a function of velocity of the body for photons constrained to one-dimensional motion, and for a full three-dimensional isotropic photon background. The derivations are carried out entirely from the point of view of a reference frame at rest relative to the isotropic photon field, so that no changes of reference frame are involved. The results for the three-dimensional model do not agree with work by previous authors, and this discrepancy is discussed. The derivations are suitable for use in the undergraduate classroom. Example cases for a light sail and a micron-sized sand grain are examined for interactions with the cosmic background radiation, assuming a temperature of 3000 K, the temperature at the time the universe became transparent, and it is found that relativistic speeds would decay on a time scale of years.

  20. Temperature surface measurements with a 3D velocity fluid flow measurement system using the same laser source and a single instrument

    NASA Astrophysics Data System (ADS)

    Rodriguez-Cervantes, Victor; Guerrero-Viramontes, J. Ascencion; Funes-Gallanzi, Marcelo

    2005-02-01

    The combination of flow velocimetry techniques and Temperature Sensitive Paints, (TSP), requires working with different laser beam intensities. Because velocity flow measurements (i.e. Particle Image Velocimetry, PIV) needs high level laser power compared with temperature surface measurement, where lower levels of laser power is required, is necessary to adjust the system to avoid the damage of the paint due to the high intensities in laser velocimetry measurements. The use of a paint of different grey levels, from white to black, as backgrounds above the TSP film deposition allows to make both, velocity and temperature measurements with the same laser power without damaging the TSP. This work is centered in the characterization, testing and calibration improvements of the temperature surface measurements using Temperature Sensitive Paints as a part of the 3D tunneling velocimetry system.

  1. Two-dimensional travel time inversion for the crustal P and S wave velocity structure of the Ruby Mountains metamorphic core complex, NE Nevada

    NASA Astrophysics Data System (ADS)

    Stoerzel, Andreas; Smithson, Scott B.

    1998-09-01

    Problems about the nature of extended crust in the Basin and Range include the role of plastic flow during extension, the possibility of fluids in the crust, and the amount of mantle-derived material added to the crust. To address these problems, the University of Wyoming conducted a multicomponent wide-angle seismic experiment in the Ruby Mountains of the Basin and Range. The northern Ruby Mountains expose upper and middle crustal rocks of a metamorphic core complex, whereas the southern Ruby Mountains consist of low-grade miogeoclinal rocks. The wide-angle experiment consisted of a 95 km long N-S profile that extended from the southern to the northern Ruby Mountains. Travel time inversion of the wide-angle reflection data reveals relatively high seismic velocities in the midcrust to lower crust which suggest that fluid-filled pores, if they exist, do not reduce the seismic velocities significantly. Therefore the midcrustal to lower crustal porosity is probably much smaller than 1-2 vol %. The average P wave velocity for the crust is 6.4-6.5 km/s in the north and 6.1-6.2 km/s in the south. This difference suggests that larger amounts of mantle-derived material were added during the Tertiary to the core complex crust of the northern Ruby Mountains than to the "normal" Basin and Range crust of the southern Ruby Mountains. The velocity profile is consistent with a maximum of 6-7 km of mantle-derived material in the south and a maximum of 12-15 km of mantle-derived material in the north. Thus volumetric mafic intrusions probably accommodated a maximum of 7 km of core complex exhumation. Shear wave splitting indicates that the upper to middle crust is seismically anisotropic probably due to superposed Tertiary plastic flow patterns. Doming and inflation of a midcrustal layer in the seismic model are compatible with Tertiary flow of material from the south to the north that compensated about 2-5 km of core complex exhumation. Precritical Moho reflections (0-70 km offset

  2. Anisotropic 3-D Crustal Velocity Structure of Idaho/ Oregon from a Joint Inversion of Group and Phase Velocities of Love and Rayleigh Waves from Ambient Seismic Noise: Results from the IDOR Project

    NASA Astrophysics Data System (ADS)

    Bremner, P. M.; Panning, M. P.; Russo, R.; Mocanu, V. I.; Stanciu, A. C.; Torpey, M. E.; Hongsresawat, S.; VanDecar, J. C.

    2015-12-01

    We present new 3-D radially anisotropic and isotropic crustal velocity models beneath central Idaho and eastern Oregon. We produced the velocity models from Love and horizontal component Rayleigh wave group and phase velocity measurements on the IDaho/ORegon (IDOR) Passive seismic network, 86 broadband seismic stations, dataset using ambient noise tomography and the methods of Gallego et. al (2010) and Lin et. al (2008). We calculated inter-station group/phase velocities in narrow frequency bands from travel-time measurements of the rotated stacked horizontal component cross-correlations (bandpass filtered between 2 and 30 seconds), which we used to invert for velocity structure beneath the network. We derived group and phase velocity maps for each frequency band using the damped least-squares inversion method of Tarantola (2005), and then jointly inverted for velocity with depth. Moho depths are prescribed in the joint inversions based on receiver functions, also from the IDOR seismic data, and provides a starting crustal velocity model. Goals of our work include refining models of crustal structure in the accreted Blue Mountain terranes in the western study area; determining the depth extent of the Salmon River Suture/West Idaho Shear Zone (WISZ), which crosses north-south through the middle of the network; determining the architecture of the Idaho batholith, an extensive largely crustal-derived pluton; and examining the nature of the autochthonous (?) North American crust and lithosphere beneath and east of the batholith.

  3. Preliminary result of teleseismic double-difference relocation of earthquakes in the Molucca collision zone with a 3D velocity model

    SciTech Connect

    Shiddiqi, Hasbi Ash E-mail: h.a.shiddiqi@gmail.com; Widiyantoro, Sri; Nugraha, Andri Dian; Ramdhan, Mohamad; Wandono,; Sutiyono,; Handayani, Titi; Nugroho, Hendro

    2015-04-24

    We have relocated hypocenters of earthquakes occurring in the Molucca collision zone and surrounding region taken from the BMKG catalog using teleseismic double-difference relocation algorithm (teletomoDD). We used P-wave arrival times of local, regional, and teleseismic events recorded at 304 recording stations. Over 7,000 earthquakes were recorded by the BMKG seismographicnetworkin the study region from April, 2009 toJune, 2014. We used a 3D regional-global nested velocity modelresulting fromprevious global tomographystudy. In this study, the3D seismic velocity model was appliedto theIndonesian region, whilethe1D seismicvelocity model (ak135)wasused for regions outside of Indonesia. Our relocation results show a better improvement in travel-time RMS residuals comparedto those of the BMKG catalog.Ourresultsalso show that relocation shifts were dominated intheeast-west direction, whichmaybeinfluenced by theexistingvelocity anomaly related to the reversed V-shaped slabbeneaththestudy region. Our eventrelocation results refine the geometry of slabs beneath the Halmahera and Sangihe arcs.

  4. Preliminary result of teleseismic double-difference relocation of earthquakes in the Molucca collision zone with a 3D velocity model

    NASA Astrophysics Data System (ADS)

    Shiddiqi, Hasbi Ash; Widiyantoro, Sri; Nugraha, Andri Dian; Ramdhan, Mohamad; Wandono, Sutiyono, Handayani, Titi; Nugroho, Hendro

    2015-04-01

    We have relocated hypocenters of earthquakes occurring in the Molucca collision zone and surrounding region taken from the BMKG catalog using teleseismic double-difference relocation algorithm (teletomoDD). We used P-wave arrival times of local, regional, and teleseismic events recorded at 304 recording stations. Over 7,000 earthquakes were recorded by the BMKG seismographicnetworkin the study region from April, 2009 toJune, 2014. We used a 3D regional-global nested velocity modelresulting fromprevious global tomographystudy. In this study, the3D seismic velocity model was appliedto theIndonesian region, whilethe1D seismicvelocity model (ak135)wasused for regions outside of Indonesia. Our relocation results show a better improvement in travel-time RMS residuals comparedto those of the BMKG catalog.Ourresultsalso show that relocation shifts were dominated intheeast-west direction, whichmaybeinfluenced by theexistingvelocity anomaly related to the reversed V-shaped slabbeneaththestudy region. Our eventrelocation results refine the geometry of slabs beneath the Halmahera and Sangihe arcs.

  5. Validation of a CFD Model by Using 3D Sonic Anemometers to Analyse the Air Velocity Generated by an Air-Assisted Sprayer Equipped with Two Axial Fans

    PubMed Central

    García-Ramos, F. Javier; Malón, Hugo; Aguirre, A. Javier; Boné, Antonio; Puyuelo, Javier; Vidal, Mariano

    2015-01-01

    A computational fluid dynamics (CFD) model of the air flow generated by an air-assisted sprayer equipped with two axial fans was developed and validated by practical experiments in the laboratory. The CFD model was developed by considering the total air flow supplied by the sprayer fan to be the main parameter, rather than the outlet air velocity. The model was developed for three air flows corresponding to three fan blade settings and assuming that the sprayer is stationary. Actual measurements of the air velocity near the sprayer were taken using 3D sonic anemometers. The workspace sprayer was divided into three sections, and the air velocity was measured in each section on both sides of the machine at a horizontal distance of 1.5, 2.5, and 3.5 m from the machine, and at heights of 1, 2, 3, and 4 m above the ground The coefficient of determination (R2) between the simulated and measured values was 0.859, which demonstrates a good correlation between the simulated and measured data. Considering the overall data, the air velocity values produced by the CFD model were not significantly different from the measured values. PMID:25621611

  6. Characterizing spatial variability in velocity and turbulence intensity using 3-D acoustic Doppler velocimeter data in a plane-bed reach of East St. Louis Creek, Colorado, USA

    NASA Astrophysics Data System (ADS)

    David, Gabrielle C. L.; Legleiter, Carl J.; Wohl, Ellen; Yochum, Steven E.

    2013-02-01

    We investigated the influence on flow resistance of flow structure and turbulence at the reach scale in a mountain channel using 3-D velocity measurements and geostatistical analysis to understand the complexity of the flow structure in a reach with limited bed irregularities. The increase in flow resistance at low flows in a plane-bed reach was not fully explained by grain resistance, therefore detailed 3-D velocity measurements were made to investigate spatial variability in velocity and turbulence components and potential controls on flow resistance. One plane-bed reach was surveyed over two stages in Fraser Experimental Forest, Colorado, using a combination of a total station, LiDAR (Light Detection and Ranging), and a SonTek Flowtracker handheld ADV (acoustic Doppler velocimeter). LiDAR was used to capture bank and channel geometry at low flows, whereas the water surface and bed data were collected with the total station at all flows. We used the standard deviation of bed elevation (σb) within a moving window as an index of roughness height (ks) and calculated the relative submergence of the bed at different stages as h/ks, where h is the local flow depth. ADV measurements were collected on a grid with a 0.3 m to 0.5 m spacing. Geostatistical analysis of the velocity data indicated that the flow was highly three-dimensional and varied based on stage, demonstrating that even small irregularities in the bed have a significant influence on the flow characteristics. The streamwise component was the largest at both low and high flow, but varied more throughout the reach at low flow. At high flow, the greatest streamwise velocities were located within the thalweg. Areas of upwelling and downwelling also varied based on stage, with this component being strongly influenced by small changes in the morphology at high flow, and by protuberant grains at low flows. The cross-stream velocity and turbulence components were controlled by the flow structure and less by the

  7. Calculation of three-dimensional (3-D) internal flow by means of the velocity-vorticity formulation on a staggered grid

    NASA Technical Reports Server (NTRS)

    Stremel, Paul M.

    1995-01-01

    A method has been developed to accurately compute the viscous flow in three-dimensional (3-D) enclosures. This method is the 3-D extension of a two-dimensional (2-D) method developed for the calculation of flow over airfoils. The 2-D method has been tested extensively and has been shown to accurately reproduce experimental results. As in the 2-D method, the 3-D method provides for the non-iterative solution of the incompressible Navier-Stokes equations by means of a fully coupled implicit technique. The solution is calculated on a body fitted computational mesh incorporating a staggered grid methodology. In the staggered grid method, the three components of vorticity are defined at the centers of the computational cell sides, while the velocity components are defined as normal vectors at the centers of the computational cell faces. The staggered grid orientation provides for the accurate definition of the vorticity components at the vorticity locations, the divergence of vorticity at the mesh cell nodes and the conservation of mass at the mesh cell centers. The solution is obtained by utilizing a fractional step solution technique in the three coordinate directions. The boundary conditions for the vorticity and velocity are calculated implicitly as part of the solution. The method provides for the non-iterative solution of the flow field and satisfies the conservation of mass and divergence of vorticity to machine zero at each time step. To test the method, the calculation of simple driven cavity flows have been computed. The driven cavity flow is defined as the flow in an enclosure driven by a moving upper plate at the top of the enclosure. To demonstrate the ability of the method to predict the flow in arbitrary cavities, results will he shown for both cubic and curved cavities.

  8. 3D CFD modeling of flowing-gas DPALs with different pumping geometries and various flow velocities

    NASA Astrophysics Data System (ADS)

    Yacoby, Eyal; Waichman, Karol; Sadot, Oren; Barmashenko, Boris D.; Rosenwaks, Salman

    2017-01-01

    Scaling-up flowing-gas diode pumped alkali lasers (DPALs) to megawatt class power is studied using accurate three-dimensional computational fluid dynamics model, taking into account the effects of temperature rise and losses of alkali atoms due to ionization. Both the maximum achievable power and laser beam quality are estimated for Cs and K lasers. We examined the influence of the flow velocity and Mach number M on the maximum achievable power of subsonic and supersonic lasers. For Cs DPAL devices with M = 0.2 - 3 the output power increases with increasing M by only 20%, implying that supersonic operation mode has only small advantage over subsonic. In contrast, the power achievable in K DPALs strongly depends on M. The output power increases by 100% when M increases from 0.2 to 4, showing a considerable advantage of supersonic device over subsonic. The reason for the increase of the power with M in both Cs and K DPALs is the decrease of the temperature due to the gas expansion in the flow system. However, the power increase for K lasers is much larger than for the Cs devices mainly due to the much smaller fine-structure splitting of the 2P states ( 58 cm-1 for K and 554 cm-1 for Cs), which results in a much stronger effect of the temperature decrease in K DPALs. For pumping by beams of the same rectangular cross section, comparison between end-pumping and transverse-pumping shows that the output power is not affected by the pump geometry. However, the intensity of the output laser beam in the case of transverse-pumped DPALs is strongly non-uniform in the laser beam cross section resulting in higher brightness and better beam quality in the far field for the end-pumping geometry where the intensity of the output beam is uniform.

  9. 3-D GPS velocity field and its implications on the present-day post-orogenic deformation of the Western Alps and Pyrenees

    NASA Astrophysics Data System (ADS)

    Ninh Nguyen, Hai; Vernant, Philippe; Mazzotti, Stephane; Khazaradze, Giorgi; Asensio, Eva

    2016-09-01

    We present a new 3-D GPS velocity solution for 182 sites for the region encompassing the Western Alps, Pyrenees, and southern France. The velocity field is based on a Precise Point Positioning (PPP) solution, to which we apply a common-mode filter, defined by the 26 longest time series, in order to correct for network-wide biases (reference frame, unmodeled large-scale processes, etc.). We show that processing parameters, such as troposphere delay modeling, can lead to systematic velocity variations of 0.1-0.5 mm yr-1 affecting both accuracy and precision, especially for short (< 5 years) time series. A velocity convergence analysis shows that minimum time-series lengths of ˜ 3 and ˜ 5.5 years are required to reach a velocity stability of 0.5 mm yr-1 in the horizontal and vertical components, respectively. On average, horizontal residual velocities show a stability of ˜ 0.2 mm yr-1 in the Western Alps, Pyrenees, and southern France. The only significant horizontal strain rate signal is in the western Pyrenees with up to 4 × 10-9 yr-1 NNE-SSW extension, whereas no significant strain rates are detected in the Western Alps (< 1 × 10-9 yr-1). In contrast, we identify significant uplift rates up to 2 mm yr-1 in the Western Alps but not in the Pyrenees (0.1 ± 0.2 mm yr-1). A correlation between site elevations and fast uplift rates in the northern part of the Western Alps, in the region of the Würmian ice cap, suggests that part of this uplift is induced by postglacial rebound. The very slow uplift rates in the southern Western Alps and in the Pyrenees could be accounted for by erosion-induced rebound.

  10. Test of high-resolution 3D P-wave velocity model of Poland by back-azimuthal sections of teleseismic receiver function

    NASA Astrophysics Data System (ADS)

    Wilde-Piorko, Monika; Polkowski, Marcin; Grad, Marek

    2015-04-01

    Geological and seismic structure under area of Poland is well studied by over one hundred thousand boreholes, over thirty deep seismic refraction and wide angle reflection profiles and by vertical seismic profiling, magnetic, gravity, magnetotelluric and thermal methods. Compilation of these studies allowed to create a high-resolution 3D P-wave velocity model down to 60 km depth in the area of Poland (Polkowski et al. 2014). Model also provides details about the geometry of main layers of sediments (Tertiary and Quaternary, Cretaceous, Jurassic, Triassic, Permian, old Paleozoic), consolidated/crystalline crust (upper, middle and lower) and uppermost mantle. This model gives an unique opportunity for calculation synthetic receiver function and compering it with observed receiver function calculated for permanent and temporary seismic stations. Modified ray-tracing method (Langston, 1977) can be used directly to calculate the response of the structure with dipping interfaces to the incoming plane wave with fixed slowness and back-azimuth. So, 3D P-wave velocity model has been interpolated to 2.5D P-wave velocity model beneath each seismic station and back-azimuthal sections of components of receiver function have been calculated. Vp/Vs ratio is assumed to be 1.8, 1.67, 1.73, 1.77 and 1.8 in the sediments, upper/middle/lower consolidated/crystalline crust and uppermost mantle, respectively. Densities were calculated with combined formulas of Berteussen (1977) and Gardner et al. (1974). Additionally, to test a visibility of the lithosphere-asthenosphere boundary phases at receiver function sections models have been extended to 250 km depth based on P4-mantle model (Wilde-Piórko et al., 2010). National Science Centre Poland provided financial support for this work by NCN grant DEC-2011/02/A/ST10/00284 and by NCN grant UMO-2011/01/B/ST10/06653.

  11. Dynamics of pickup ion velocity distribution function in Titan's plasma environment (TA encounter): 3D hybrid kinetic modeling and comparison with CAPS observations

    NASA Astrophysics Data System (ADS)

    Simpson, D. G.; Lipatov, A. S.; Sittler, E. C.; Hartle, R. E.; Cooper, J. F.

    2013-12-01

    Wave-particle interactions play a very important role in the plasma dynamics near Titan: mass loading, excitation of the low-frequency waves and the formation of the particle velocity distribution function, e.g. ring/shell-like distributions, etc. The kinetic approach is important for estimation of the collision processes e.g. a charge exchange. The particle velocity distribution function also plays a key role for understanding the observed particle fluxes. In this report we discuss the ion velocity distribution function dynamics from 3D hybrid modeling. The modeling is based on recent analysis of the Cassini Plasma Spectrometer (CAPS) ion measurements during the TA flyby. In our model the background ions, all pickup ions, and ionospheric ions are considered as particles, whereas the electrons are described as a fluid. Inhomogeneous photoionization, electron-impact ionization and charge exchange are included in our model. The temperatures of the background electrons and pickup electrons were also included into the generalized Ohm's law. We also take into account the collisions between the ions and neutrals. We use Chamberlain profiles for the exosphere's components and include a simple ionosphere model with M=28 ions that were generated inside the ionosphere. The moon is considered as a weakly conducting body. Our modeling shows that interaction between background plasma and pickup ions H+, H2+, CH4+ and N2+ has a more complicated structure than was observed in the T9 flyby and modeling due to the large gyroradius of the background O+ ions [1,2,3,4]. Special attention will be paid to comparing the simulated pickup ion velocity distribution with CAPS TA observations. We also compare our kinetic modeling with other hybrid and MHD modeling of Titan's environment. References [1] Sittler, E.C., et al., Energy Deposition Processes in Titan's Upper Atmosphere and Its Induced Magnetosphere. In: Titan from Cassini-Huygens, Brown, R.H., Lebreton J.P., Waite, J.H., Eds

  12. Identification of source velocities on 3D structures in non-anechoic environments: Theoretical background and experimental validation of the inverse patch transfer functions method

    NASA Astrophysics Data System (ADS)

    Aucejo, M.; Totaro, N.; Guyader, J.-L.

    2010-08-01

    In noise control, identification of the source velocity field remains a major problem open to investigation. Consequently, methods such as nearfield acoustical holography (NAH), principal source projection, the inverse frequency response function and hybrid NAH have been developed. However, these methods require free field conditions that are often difficult to achieve in practice. This article presents an alternative method known as inverse patch transfer functions, designed to identify source velocities and developed in the framework of the European SILENCE project. This method is based on the definition of a virtual cavity, the double measurement of the pressure and particle velocity fields on the aperture surfaces of this volume, divided into elementary areas called patches and the inversion of impedances matrices, numerically computed from a modal basis obtained by FEM. Theoretically, the method is applicable to sources with complex 3D geometries and measurements can be carried out in a non-anechoic environment even in the presence of other stationary sources outside the virtual cavity. In the present paper, the theoretical background of the iPTF method is described and the results (numerical and experimental) for a source with simple geometry (two baffled pistons driven in antiphase) are presented and discussed.

  13. Background and Pickup Ion Velocity Distribution Dynamics in Titan's Plasma Environment: 3D Hybrid Simulation and Comparison with CAPS T9 Observations

    NASA Technical Reports Server (NTRS)

    Lipatov, A. S.; Sittler, E. C., Jr.; Hartle, R. E.; Cooper, J. F.; Simpson, D. G.

    2011-01-01

    In this report we discuss the ion velocity distribution dynamics from the 3D hybrid simulation. In our model the background, pickup, and ionospheric ions are considered as a particles, whereas the electrons are described as a fluid. Inhomogeneous photoionization, electron-impact ionization and charge exchange are included in our model. We also take into account the collisions between the ions and neutrals. The current simulation shows that mass loading by pickup ions H(+); H2(+), CH4(+) and N2(+) is stronger than in the previous simulations when O+ ions are introduced into the background plasma. In our hybrid simulations we use Chamberlain profiles for the atmospheric components. We also include a simple ionosphere model with average mass M = 28 amu ions that were generated inside the ionosphere. The moon is considered as a weakly conducting body. Special attention will be paid to comparing the simulated pickup ion velocity distribution with CAPS T9 observations. Our simulation shows an asymmetry of the ion density distribution and the magnetic field, including the formation of the Alfve n wing-like structures. The simulation also shows that the ring-like velocity distribution for pickup ions relaxes to a Maxwellian core and a shell-like halo.

  14. New constraints on the 3D shear wave velocity structure of the upper mantle underneath Southern Scandinavia revealed from non-linear tomography

    NASA Astrophysics Data System (ADS)

    Wawerzinek, B.; Ritter, J. R. R.; Roy, C.

    2013-08-01

    We analyse travel times of shear waves, which were recorded at the MAGNUS network, to determine the 3D shear wave velocity (vS) structure underneath Southern Scandinavia. The travel time residuals are corrected for the known crustal structure of Southern Norway and weighted to account for data quality and pick uncertainties. The resulting residual pattern of subvertically incident waves is very uniform and simple. It shows delayed arrivals underneath Southern Norway compared to fast arrivals underneath the Oslo Graben and the Baltic Shield. The 3D upper mantle vS structure underneath the station network is determined by performing non-linear travel time tomography. As expected from the residual pattern the resulting tomographic model shows a simple and continuous vS perturbation pattern: a negative vS anomaly is visible underneath Southern Norway relative to the Baltic Shield in the east with a contrast of up to 4% vS and a sharp W-E dipping transition zone. Reconstruction tests reveal besides vertical smearing a good lateral reconstruction of the dipping vS transition zone and suggest that a deep-seated anomaly at 330-410 km depth is real and not an inversion artefact. The upper part of the reduced vS anomaly underneath Southern Norway (down to 250 km depth) might be due to an increase in lithospheric thickness from the Caledonian Southern Scandes in the west towards the Proterozoic Baltic Shield in Sweden in the east. The deeper-seated negative vS anomaly (330-410 km depth) could be caused by a temperature anomaly possibly combined with effects due to fluids or hydrous minerals. The determined simple 3D vS structure underneath Southern Scandinavia indicates that mantle processes might influence and contribute to a Neogene uplift of Southern Norway.

  15. 3D time-lapse seismic traveltime tomography for detecting near surface velocity variations: a case study from the Ketzin CO2 storage pilot site

    NASA Astrophysics Data System (ADS)

    Zhang, Fengjiao; Juhlin, Christopher; Huang, Fei; Lüth, Stefan

    2016-04-01

    Time-lapse seismic methods are an important tool for monitoring CO2 migration and storage in geological formations. Near surface variations are one of the major problems which may introduce time-lapse noise in the application of land based seismic monitoring. Conventional reflection seismic methods have difficulties in imaging near surface structures (10-30 m depth) due to the limitation of the methods themselves. Traveltime tomography is a commonly used method to reconstruct the subsurface velocity model. It can often provide extra information on near surface structures which is difficult to obtain by the conventional reflection seismic method. In this study, we apply traveltime tomography to 3D time-lapse seismic data sets acquired from at the Ketzin CO2 storage site. We also test different inversion strategies for traveltime tomography to investigate which one is more suitable for this case study. The results show good correlation with near surface variations obtained by other studies.

  16. Solar Wind Halo Formation by the Scattering of the Strahl via Direct Cluster/PEACE Observations of the 3D Velocity Distribution Function

    NASA Technical Reports Server (NTRS)

    Figueroa-Vinas, Adolfo; Gurgiolo, Chris A.; Nieves-Chinchilla, Teresa; Goldstein, Melvyn L.

    2010-01-01

    It has been suggested by a number of authors that the solar wind electron halo can be formed by the scattering of the strahl. On frequent occasions we have observed in electron angular skymaps (Phi/Theta-plots) of the electron 3D velocity distribution functions) a bursty-filament of particles connecting the strahl to the solar wind core-halo. These are seen over a very limited energy range. When the magnetic field is well off the nominal solar wind flow direction such filaments are inconsistent with any local forces and are probably the result of strong scattering. Furthermore, observations indicates that the strahl component is frequently and significantly anisotropic (Tper/Tpal approx.2). This provides a possible free energy source for the excitation of whistler waves as a possible scattering mechanism. The empirical observational evidence between the halo and the strahl suggests that the strahl population may be, at least in part, the source of the halo component.

  17. Developing Regionalized Models of Lithospheric Thickness and Velocity Structure Across Eurasia and the Middle East from Jointly Inverting P-Wave and S-Wave Receiver Functions with Rayleigh Wave Group and Phase Velocities

    DTIC Science & Technology

    2011-09-01

    DEVELOPING REGIONALIZED MODELS OF LITHOSPHERIC THICKNESS AND VELOCITY STRUCTURE ACROSS EURASIA AND THE MIDDLE EAST FROM JOINTLY INVERTING P-WAVE...09NA293221 and DE-AC52-07NA273442 Proposal No. BAA09-13 ABSTRACT The main goal of this project is to develop models of lithospheric velocity...of the lithosphere are key for accurately modeling not only travel times but also surface-wave dispersion velocities and full waveforms at regional

  18. Contribution of a 3D velocity model and of beam forming method for the location of microseismic sources generated in soft rock landslides

    NASA Astrophysics Data System (ADS)

    Provost, Floriane; Malet, Jean-Philippe; Helmstetter, Agnès; Doubre, Cécile; Gance, Julien

    2016-04-01

    Microseismicity monitoring has proven to be an important tool for a better understanding of the deformation occurring in slow-sliding landslides. However locating the seismic sources generated by a landslide remains a challenging problem due to (1) the small sizes of the landslide, (b) the heterogenous and time-changing petro-physical properties of the landslide material, (c) the complexity of the recorded signals with unclear discriminations of the wave onsets, and (d) the difficulties to install and maintain a dense seismological network on-site close to the seismic sources. We studied the seismic sources generated by the deformation of the clay-rich Super-Sauze landslide (South French Alps). Previous studies show that the most active zone is the uphill part of the landslide within a zone of 300x300m2. Two seismic antennas have been installed on the sides of this zone and a seismic campaign was conducted to build a 3D velocity model of the area. Calibration shots were performed to test the performance of the location method. We show that the use of a 3D velocity model integrated in a beam forming location method slightly improves the accuracy of the shot location epicenter. However, this approach does not help to interpret with confidence the location of the natural events because the horizontal error remains larger than 50m for more than 50% of the shots. Nevertheless, adding station corrections and constraining the grid search area with additional informations based on the signal and the landslide behavior such as SNR, seismic event typology, and surface kinematics of the landslide allow obtaining reliable results. More than 70% of the calibration shots could be located with a horizontal error of less than 40m. The lack of sensor installed in depth as well as the the lack of calibration shots realized at different depths does not permit us to identify the depth of the sources.

  19. Constructing a starting 3D shear velocity model with sharp interfaces for SEM-based upper mantle tomography in North America

    NASA Astrophysics Data System (ADS)

    Calo, M.; Bodin, T.; Yuan, H.; Romanowicz, B. A.; Larmat, C. S.; Maceira, M.

    2013-12-01

    this work we propose instead to directly tackle the non-linearity of the inverse problem by using stochastic methods to construct a 3D starting model with a good estimate of the depths of the main layering interfaces. We present preliminary results of the construction of such a starting 3D model based on: (1) Regionalizing the study area to define provinces within which lateral variations are smooth; (2) Applying trans-dimensional stochastic inversion (Bodin et al., 2012) to obtain accurate 1D models in each province as well as the corresponding error distribution, constrained by receiver function and surface wave dispersion data as well as the previously constructed 3D model (name), and (3) connecting these models laterally using data-driven smoothing operators to obtain a starting 3D model with errors. References Bodin, T.,et al. 2012, Transdimensional inversion of receiver functions and surface wave dispersion, J. Geophys. Res., 117, B02301, doi:10.1029/2011JB008560. Yuan and Romanowicz, 2013, in revison. Yuan, H., et al. 2011, 3-D shear wave radially and azimuthally anisotropic velocity model of the North American upper mantle. Geophysical Journal International, 184: 1237-1260. doi: 10.1111/j.1365-246X.2010.04901.x Yuan, H. & Romanowicz, B., 2010. Lithospheric layering in the North American Craton, Nature, 466, 1063-1068.

  20. New insights in the velocity dependency of the external mass transfer coefficient in 2D and 3D porous media for liquid chromatography.

    PubMed

    Deridder, Sander; Desmet, Gert

    2012-03-02

    Numerical calculations of the mobile zone mass transfer rate in a variety of ordered 2D and 3D structures are presented. These calculations are in line with earlier theoretical and experimental findings made in the field of chemical engineering and suggest that the Sherwood-number (Sh(m)) appearing in the mobile phase mass transfer term of the general plate height expression of liquid chromatography is not correctly predicted by the Wilson-Geankoplis--or the Kataoka--or the penetration model expression that have been used up to now to in the field of LC, and that at least more research is needed before these expressions can be continued to be used with confidence. The aforementioned expressions were obtained by neglecting the effect of axial dispersion on the mass transfer process, and it seems that they therefore underestimate the true Sh(m)-number by a factor of 2-5 around the minimum of the van Deemter-curve. New correlations describing the variation of the Sh(m)-coefficient as a function of the reduced velocity for a number of other packing geometries (tetrahedral monolith, 2D pillar array) are proposed. These correlations are in agreement with earlier theoretical and experimental studies showing that at low velocities the local-driving force-based Sh(m)-value is of the order of 10-20 in a packed bed column with an external porosity on the order of 35-40%.

  1. Can we trace the eastern Gondwanan margin in Australia? New perspectives from transdimensional inversion of ambient noise for 3D shear velocity structure

    NASA Astrophysics Data System (ADS)

    Pilia, S.; Rawlinson, N.; Direen, N. G.

    2013-12-01

    Although the notion of Rodinia is quite well accepted in the geoscience community, the location and nature of the eastern continental margin of the Gondwana fragment in Australia is still vague and remains one of the most hotly debated topics in Australian geology. Moreover, most post-Rodinian reconstructions models choose not to tackle the ';Tasmanian challenge', and focus only on the tectonic evolution of mainland southeast Australia, thereby conveniently ignoring the wider tectonic implications of Tasmania's complex geological history. One of the chief limitations of the tectonic reconstructions in this region is a lack of information on Paleozoic (possibly Proterozoic) basement structures. Vast Mesozoic-Cainozoic sedimentary and volcanic cover sequences obscure older outcrops and limit the power of direct observational techniques. In response to these challenges, our effort is focused on ambient seismic noise for imaging 3D crustal shear velocity structure using surface waves, which is capable of illuminating basement structure beneath younger cover. The data used in this study is sourced from the WOMBAT transportable seismic array, which is compounded by around 650 stations spanning the majority of southeastern Australia, including Tasmania and several islands in Bass Strait. To produce the highest quality Green's functions, careful processing of the data has been performed, after which group velocity dispersion measurements have been carried out using a frequency-time analysis method on the symmetric component of the empirical Green's functions (EGFs). Group dispersion measurements from the EGFs have been inverted using a novel hierarchical, transdimensional, Bayesian algorithm to obtain Rayleigh-wave group velocity maps at different periods from 2 to 30 s. The new approach has several advantages in that the number and distribution of model parameters are implicitly controlled by the data, in which the noise is treated as unknown in the inversion. This

  2. Developing Regionalized Models of Lithospheric Thickness and Velocity Structure Across Eurasia and the Middle East from Jointly Inverting P-Wave and S-Wave Receiver Functions with Rayleigh Wave Group and Phase Velocities

    DTIC Science & Technology

    2010-09-01

    DEVELOPING REGIONALIZED MODELS OF LITHOSPHERIC THICKNESS AND VELOCITY STRUCTURE ACROSS EURASIA AND THE MIDDLE EAST FROM JOINTLY INVERTING P-WAVE... lithospheric velocity structure for a wide variety of tectonic regions throughout Eurasia and the Middle East. We expect the regionalized models will improve...important differences in lithospheric structure between the cratonic regions of Eastern Europe and the tectonic regions of Western Europe and the

  3. High-Resolution Seismic Images and 3-D Seismic Velocities of the San Andreas Fault Zone at Burro Flats, Southern California

    NASA Astrophysics Data System (ADS)

    Tsai, C.; Catchings, R. D.; Rymer, M. J.; Goldman, M. R.

    2003-12-01

    The southern San Andreas fault (SAF) has produced large earthquakes in the past 1500 yrs. Burro Flats, a basin within the San Bernardino Mountains, is bounded on the southwest by the southern San Andreas fault. Burro Flats has been the site of paleoseismological investigations to determine the slip history of the fault. Additional paleoseismic studies at this location are needed to further resolve the structure and slip history of the SAF. In addition to the main trace of the SAF at Burro Flats, there are splay faults, suggesting a complex geometry for the fault. To better understand the structure of the SAF, we acquired a 3-D, combined seismic reflection/refraction profile centered on the main trace at Burro Flats. The seismic investigation included a 60 m by 70 m rectangular array. Sensors were spaced every 5 m; seismic sources, likewise with a spacing of 5 m, consisted of a combination of down-hole explosives and shallow (approximately 0.3 m) Betsy Seisgun shots. Data were recorded without acquisition filters for 5 s at a 0.5-ms sampling rate. To analyze the data for velocity structure, we used a tomographic inversion procedure to invert first-arrival refractions. Preliminary measurements from shot gathers show that near-surface velocities range between 700 m/s and 1500 m/s. We observe apparent travel-time delays of approximately 7 ms near the main surface trace of the SAF, suggesting that seismic imaging methods may be useful in identifying this and other fault traces. These results will be useful for paleoseismic investigations.

  4. P and S wave tomography of the mantle beneath the United States

    NASA Astrophysics Data System (ADS)

    Schmandt, Brandon; Lin, Fan-Chi

    2014-09-01

    Mantle seismic structure beneath the United States spanning from the active western plate margin to the passive eastern margin was imaged with teleseismic P and S wave traveltime tomography including USArray data up to May 2014. To mitigate artifacts from crustal structure 5-40 s, Rayleigh wave phase velocities were used to create a 3-D starting model. Major features of the final P and S models include two distinct low-velocity anomalies at depths of ~60-300 km beneath the central and northern Appalachians and passive margin. The central Appalachian low-velocity anomaly coincides with Eocene basaltic magmatism, and the northern anomaly is located along the Cretaceous track of the Great Meteor hot spot. At depths of ~300-700 km beneath the central and eastern U.S. large high-velocity anomalies are inferred to be remnants of the Farallon slab that subducted prior to ~40 Ma during the Laramide orogeny.

  5. Solar Wind Halo Formation by the Scattering of the Strahl: Direct Cluster/PEACE Observations of the 3D Velocity Distribution Function

    NASA Astrophysics Data System (ADS)

    Vinas, A. F.; Gurgiolo, C. A.; Nieves-Chinchilla, T.; Wendel, D. E.; Goldstein, M. L.; Fazakerley, A. N.

    2010-12-01

    The current hypothesis of the formation of the solar wind halo electrons is that they are produced from scattering of the strahl. This hypothesis is strengthened by direct observations of the strahl electrons being scattered into the halo in an isolated event. On frequent occasions we have observed in electron angular skymaps (Phi/Theta-plots) of the electron 3D velocity distribution functions, a bursty-filament of particles connecting the strahl to the solar wind core-halo. These are seen over a limited energy range. The observation implies that the formation of the halo is not a continuous process but occurs in bursts in regions where conditions for wave growth providing the scattering are optimum. Sometimes, observations indicates that the strahl component is anisotropic (Tper/Tpal ~ 2). This provides a possible free energy source for the excitation of whistler waves as a possible scattering mechanism, however this condition is not always observed. The empirical observational evidence between the halo and the strahl suggests that the strahl population may be, at least in part, the source of the halo component.

  6. A methodology to accurately quantify patellofemoral cartilage contact kinematics by combining 3D image shape registration and cine-PC MRI velocity data.

    PubMed

    Borotikar, Bhushan S; Sipprell, William H; Wible, Emily E; Sheehan, Frances T

    2012-04-05

    Patellofemoral osteoarthritis and its potential precursor patellofemoral pain syndrome (PFPS) are common, costly, and debilitating diseases. PFPS has been shown to be associated with altered patellofemoral joint mechanics; however, an actual variation in joint contact stresses has not been established due to challenges in accurately quantifying in vivo contact kinematics (area and location). This study developed and validated a method for tracking dynamic, in vivo cartilage contact kinematics by combining three magnetic resonance imaging (MRI) techniques, cine-phase contrast (CPC), multi-plane cine (MPC), and 3D high-resolution static imaging. CPC and MPC data were acquired from 12 healthy volunteers while they actively extended/flexed their knee within the MRI scanner. Since no gold standard exists for the quantification of in vivo dynamic cartilage contact kinematics, the accuracy of tracking a single point (patellar origin relative to the femur) represented the accuracy of tracking the kinematics of an entire surface. The accuracy was determined by the average absolute error between the PF kinematics derived through registration of MPC images to a static model and those derived through integration of the CPC velocity data. The accuracy ranged from 0.47 mm to 0.77 mm for the patella and femur and from 0.68 mm to 0.86 mm for the patellofemoral joint. For purely quantifying joint kinematics, CPC remains an analytically simpler and more accurate (accuracy <0.33 mm) technique. However, for application requiring the tracking of an entire surface, such as quantifying cartilage contact kinematics, this combined imaging approach produces accurate results with minimal operator intervention.

  7. System and method for investigating sub-surface features and 3D imaging of non-linear property, compressional velocity VP, shear velocity VS and velocity ratio VP/VS of a rock formation

    DOEpatents

    Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre-Yves; Larmat, Carene S.

    2015-06-02

    A system and a method for generating a three-dimensional image of a rock formation, compressional velocity VP, shear velocity VS and velocity ratio VP/VS of a rock formation are provided. A first acoustic signal includes a first plurality of pulses. A second acoustic signal from a second source includes a second plurality of pulses. A detected signal returning to the borehole includes a signal generated by a non-linear mixing process from the first and second acoustic signals in a non-linear mixing zone within an intersection volume. The received signal is processed to extract the signal over noise and/or signals resulting from linear interaction and the three dimensional image of is generated.

  8. Corrigendum to "The 3-D strain patterns in Turkey using geodetic velocity fields from the RTK-CORS (TR) network" [J. African Earth Sci. 115 (2016) 246-270

    NASA Astrophysics Data System (ADS)

    Kutoglu, Hakan Senol; Toker, Mustafa; Mekik, Cetin

    2016-12-01

    In the article titled "The 3-D Strain patterns in Turkey using Geodetic velocity fields from the RTK-CORS (TR) Network" published in Journal of African Earth Sciences Vol. 11, pp.246-270, the black arrows on the Figs. 10 and 12 are shifted due to printing error to undesired places. The correct form of Figs. 10 and 12 are given below:

  9. S-wave refraction survey of alluvial aggregate

    USGS Publications Warehouse

    Ellefsen, Karl J.; Tuttle, Gary J.; Williams, Jackie M.; Lucius, Jeffrey E.

    2005-01-01

    An S-wave refraction survey was conducted in the Yampa River valley near Steamboat Springs, Colo., to determine how well this method could map alluvium, a major source of construction aggregate. At the field site, about 1 m of soil overlaid 8 m of alluvium that, in turn, overlaid sedimentary bedrock. The traveltimes of the direct and refracted S-waves were used to construct velocity cross sections whose various regions were directly related to the soil, alluvium, and bed-rock. The cross sections were constrained to match geologic logs that were developed from drill-hole data. This constraint minimized the ambiguity in estimates of the thickness and the velocity of the alluvium, an ambiguity that is inherent to the S-wave refraction method. In the cross sections, the estimated S-wave velocity of the alluvium changed in the horizontal direction, and these changes were attributed to changes in composition of the alluvium. The estimated S-wave velocity of the alluvium was practically constant in the vertical direc-tion, indicating that the fine layering observed in the geologic logs could not be detected. The S-wave refraction survey, in conjunction with independent information such as geologic logs, was found to be suitable for mapping the thickness of the alluvium.

  10. Hip and knee joints are more stabilized than driven during the stance phase of gait: an analysis of the 3D angle between joint moment and joint angular velocity.

    PubMed

    Dumas, R; Cheze, L

    2008-08-01

    Joint power is commonly used in orthopaedics, ergonomics or sports analysis but its clinical interpretation remains controversial. Some basic principles on muscle actions and energy transfer have been proposed in 2D. The decomposition of power on 3 axes, although questionable, allows the same analysis in 3D. However, these basic principles have been widely criticized, mainly because bi-articular muscles must be considered. This requires a more complex computation in order to determine how the individual muscle force contributes to drive the joint. Conversely, with simple 3D inverse dynamics, the analysis of both joint moment and angular velocity directions is essential to clarify when the joint moment can contribute or not to drive the joint. The present study evaluates the 3D angle between the joint moment and the joint angular velocity and investigates when the hip, knee and ankle joints are predominantly driven (angle close to 0 degrees and 180 degrees ) or stabilized (angle close to 90 degrees ) during gait. The 3D angle curves show that the three joints are never fully but only partially driven and that the hip and knee joints are mainly stabilized during the stance phase. The notion of stabilization should be further investigated, especially for subjects with motion disorders or prostheses.

  11. Elastic reverse-time migration based on amplitude-preserving P- and S-wave separation

    NASA Astrophysics Data System (ADS)

    Yang, Jia-Jia; Luan, Xi-Wu; Fang, Gang; Liu, Xin-Xin; Pan, Jun; Wang, Xiao-Jie

    2016-09-01

    Imaging the PP- and PS-wave for the elastic vector wave reverse-time migration requires separating the P- and S-waves during the wave field extrapolation. The amplitude and phase of the P- and S-waves are distorted when divergence and curl operators are used to separate the P- and S-waves. We present a P- and S-wave amplitude-preserving separation algorithm for the elastic wavefield extrapolation. First, we add the P-wave pressure and P-wave vibration velocity equation to the conventional elastic wave equation to decompose the P- and S-wave vectors. Then, we synthesize the scalar P- and S-wave from the vector Pand S-wave to obtain the scalar P- and S-wave. The amplitude-preserved separated P- and S-waves are imaged based on the vector wave reverse-time migration (RTM). This method ensures that the amplitude and phase of the separated P- and S-wave remain unchanged compared with the divergence and curl operators. In addition, after decomposition, the P-wave pressure and vibration velocity can be used to suppress the interlayer reflection noise and to correct the S-wave polarity. This improves the image quality of P- and S-wave in multicomponent seismic data and the true-amplitude elastic reverse time migration used in prestack inversion.

  12. Volcano-tectonic implications of 3-D velocity structures derived from joint active and passive source tomography of the island of Hawaii

    USGS Publications Warehouse

    Park, J.; Morgan, J.K.; Zelt, C.A.; Okubo, P.G.

    2009-01-01

    We present a velocity model of the onshore and offshore regions around the southern part of the island of Hawaii, including southern Mauna Kea, southeastern Hualalai, and the active volcanoes of Mauna Loa, and Kilauea, and Loihi seamount. The velocity model was inverted from about 200,000 first-arrival traveltime picks of earthquakes and air gun shots recorded at the Hawaiian Volcano Observatory (HVO). Reconstructed volcanic structures of the island provide us with an improved understanding of the volcano-tectonic evolution of Hawaiian volcanoes and their interactions. The summits and upper rift zones of the active volcanoes are characterized by high-velocity materials, correlated with intrusive magma cumulates. These high-velocity materials often do not extend the full lengths of the rift zones, suggesting that rift zone intrusions may be spatially limited. Seismicity tends to be localized seaward of the most active intrusive bodies. Low-velocity materials beneath parts of the active rift zones of Kilauea and Mauna Loa suggest discontinuous rift zone intrusives, possibly due to the presence of a preexisting volcanic edifice, e.g., along Mauna Loa beneath Kilauea's southwest rift zone, or alternatively, removal of high-velocity materials by large-scale landsliding, e.g., along Mauna Loa's western flank. Both locations also show increased seismicity that may result from edifice interactions or reactivation of buried faults. New high-velocity regions are recognized and suggest the presence of buried, and in some cases, previously unknown rift zones, within the northwest flank of Mauna Loa, and the south flanks of Mauna Loa, Hualalai, and Mauna Kea. Copyright 2009 by the American Geophysical Union.

  13. Along-strike variation in subducting plate velocity induced by along-strike variation in overriding plate structure: Insights from 3D numerical models

    NASA Astrophysics Data System (ADS)

    Rodríguez-González, Juan; Billen, Magali I.; Negredo, Ana M.; Montesi, Laurent G. J.

    2016-10-01

    Subduction dynamics can be understood as the result of the balance between driving and resisting forces. Previous work has traditionally regarded gravitational slab pull and viscous mantle drag as the main driving and resistive forces for plate motion respectively. However, this paradigm fails to explain many of the observations in subduction zones. For example, subducting plate velocity varies significantly along-strike in many subduction zones and this variation is not correlated to the age of subducting lithosphere. Here we present three-dimensional and time-dependent numerical models of subduction. We show that along-strike variations of the overriding plate thermal structure can lead to along-strike variations in subducting plate velocity. In turn, velocity variations lead to significant migration of the Euler pole over time. Our results show that the subducting plate is slower beneath the colder portion of the overriding plate due to two related mechanisms. First, the mantle wedge beneath the colder portion of the overriding plate is more viscous, which increases mantle drag. Second, where the mantle wedge is more viscous, hydrodynamic suction increases, leading to a lower slab dip. Both factors contribute to decreasing subducting plate velocity in the region; therefore, if the overriding plate is not uniform, the resulting velocity varies significantly along-strike, which causes the Euler pole to migrate closer to the subducting plate. We present a new mechanism to explain observations of subducting plate velocity in the Cocos and Nazca plates. These results shed new light on the balance of forces that control subduction dynamics and prove that future studies should take into consideration the three-dimensional structure of the overriding plate.

  14. Constraining Source Locations of Shallow Subduction Megathrust Earthquakes in 1-D and 3-D Velocity Models - A Case Study of the 2002 Mw=6.4 Osa Earthquake, Costa Rica

    NASA Astrophysics Data System (ADS)

    Grevemeyer, I.; Arroyo, I. G.

    2015-12-01

    Earthquake source locations are generally routinely constrained using a global 1-D Earth model. However, the source location might be associated with large uncertainties. This is definitively the case for earthquakes occurring at active continental margins were thin oceanic crust subducts below thick continental crust and hence large lateral changes in crustal thickness occur as a function of distance to the deep-sea trench. Here, we conducted a case study of the 2002 Mw 6.4 Osa thrust earthquake in Costa Rica that was followed by an aftershock sequence. Initial relocations indicated that the main shock occurred fairly trenchward of most large earthquakes along the Middle America Trench off central Costa Rica. The earthquake sequence occurred while a temporary network of ocean-bottom-hydrophones and land stations 80 km to the northwest were deployed. By adding readings from permanent Costa Rican stations, we obtain uncommon P wave coverage of a large subduction zone earthquake. We relocated this catalog using a nonlinear probabilistic approach using a 1-D and two 3-D P-wave velocity models. The 3-D model was either derived from 3-D tomography based on onshore stations and a priori model based on seismic refraction data. All epicentres occurred close to the trench axis, but depth estimates vary by several tens of kilometres. Based on the epicentres and constraints from seismic reflection data the main shock occurred 25 km from the trench and probably along the plate interface at 5-10 km depth. The source location that agreed best with the geology was based on the 3-D velocity model derived from a priori data. Aftershocks propagated downdip to the area of a 1999 Mw 6.9 sequence and partially overlapped it. The results indicate that underthrusting of the young and buoyant Cocos Ridge has created conditions for interpolate seismogenesis shallower and closer to the trench axis than elsewhere along the central Costa Rica margin.

  15. Numerical Investigation of 3D multichannel analysis of surface wave method

    NASA Astrophysics Data System (ADS)

    Wang, Limin; Xu, Yixian; Luo, Yinhe

    2015-08-01

    Multichannel analysis of surface wave (MASW) method is an efficient tool to obtain near-surface S-wave velocity, and it has gained popularity in engineering practice. Up to now, most examples of using the MASW technique are focused on 2D models or data from a 1D linear receiver spread. We propose a 3D MASW scheme. A finite-difference (FD) method is used to investigate the method using linear and fan-shaped receiver spreads. Results show that the 3D topography strongly affects propagation of Rayleigh waves. The energy concentration of dispersion image is distorted and bifurcated because of the influence of free-surface topography. These effects are reduced with the 3D MASW method. Lastly we investigate the relation between the array size and the resolution of dispersion measurement.

  16. A new approach to obtaining a 3D shear wave velocity model of the crust and upper mantle: An application to eastern Turkey

    NASA Astrophysics Data System (ADS)

    Delph, Jonathan R.; Zandt, George; Beck, Susan L.

    2015-12-01

    We present a new approach to the joint inversion of surface wave dispersion data and receiver functions by utilizing Common Conversion Point (CCP) stacking to reconcile the different sampling domains of the two datasets. Utilizing CCP stacking allows us to suppress noise in the data by waveform stacking, and correct for backazimuthal variations and complex crustal structure by mapping receiver functions back to their theoretical location. When applied to eastern Turkey, this approach leads to a higher resolution image of the subsurface and clearly delineates different tectonic features in eastern Turkey that were not apparent using other approaches. We observe that the slow seismic velocities near the Karliova Triple Junction correlate to moderate strain rates and high heat flow, which leads to a rheologically weak crust that has allowed for the upward propagation of Miocene and younger volcanics near the triple junction. We find seismically fast, presumably rigid blocks located in the southeastern Anatolian Plate and Arabian Plate are separated by a band of low shear wave velocities that correspond to the East Anatolian Fault Zone, which is consistent with the presence of fluids in the fault zone. We observe that the Arabian Plate has underthrust the Eurasian Plate as far as the northern boundary of the Bitlis Massif, which can explain the high exhumation rates in the Bitlis Massif as a result of slab break-off of the Arabian oceanic lithosphere. We also find a shallow ( 33 km) anomaly beneath eastern Turkey that we interpret as a localized wedge of mantle that was underthrust by a crustal fragment during the collision of Arabia and Eurasia. These observations are possible because of the high-resolution images obtained by combining common conversion point receiver function stacks with ambient noise dispersion data to create a data-driven three-dimensional shear wave velocity model.

  17. 3D Position and Velocity Vector Computations of Objects Jettisoned from the International Space Station Using Close-Range Photogrammetry Approach

    NASA Technical Reports Server (NTRS)

    Papanyan, Valeri; Oshle, Edward; Adamo, Daniel

    2008-01-01

    Measurement of the jettisoned object departure trajectory and velocity vector in the International Space Station (ISS) reference frame is vitally important for prompt evaluation of the object s imminent orbit. We report on the first successful application of photogrammetric analysis of the ISS imagery for the prompt computation of the jettisoned object s position and velocity vectors. As post-EVA analyses examples, we present the Floating Potential Probe (FPP) and the Russian "Orlan" Space Suit jettisons, as well as the near-real-time (provided in several hours after the separation) computations of the Video Stanchion Support Assembly Flight Support Assembly (VSSA-FSA) and Early Ammonia Servicer (EAS) jettisons during the US astronauts space-walk. Standard close-range photogrammetry analysis was used during this EVA to analyze two on-board camera image sequences down-linked from the ISS. In this approach the ISS camera orientations were computed from known coordinates of several reference points on the ISS hardware. Then the position of the jettisoned object for each time-frame was computed from its image in each frame of the video-clips. In another, "quick-look" approach used in near-real time, orientation of the cameras was computed from their position (from the ISS CAD model) and operational data (pan and tilt) then location of the jettisoned object was calculated only for several frames of the two synchronized movies. Keywords: Photogrammetry, International Space Station, jettisons, image analysis.

  18. Numerical Study of Velocity Shear Stabilization of 3D and Theoretical Considerations for Centrifugally Confined Plasmas and Other Interchange-Limited Fusion Concepts

    SciTech Connect

    Hassam, Adil

    2015-09-21

    We studied the feasibility of resonantly driving GAMs in tokamaks. A numerical simulation was carried out and showed the essential features and limitations. It was shown further that GAMs can damp by phase-mixing, from temperature gradients, or nonlinear detuning, thus broadening the resonance. Experimental implications of this were quantified. Theoretical support was provided for the Maryland Centrifugal Experiment, funded in a separate grant by DOE. Plasma diamagnetism from supersonic rotation was established. A theoretical model was built to match the data. Additional support to the experiment in terms of numerical simulation of the interchange turbulence was provided. Spectra from residual turbulence on account of velocity shear suppression were obtained and compared favorably to experiment. A new drift wave, driven solely by the thermal force, was identified.

  19. 3D velocity field time series using synthetic aperture radar: application to tidal-timescale ice-flow variability in Rutford Ice Stream, West Antarctica

    NASA Astrophysics Data System (ADS)

    Milillo, Pietro; Minchew, Brent; Agram, Piyush; Riel, Bryan; Simons, Mark

    2016-10-01

    We present a general method for retrieving time-series of three component surface velocity field vector given a set of continuous synthetic aperture radar (SAR) acquisitions collected from multiple geometries. Our algorithm extends the single-line-of-sight mathematical framework developed for time-series analysis using interferometric SAR (InSAR) to three spatial dimensions. The inversion is driven by a design matrix corresponding to a dictionary of displacement functions parameterized in time. The resulting model minimizes a cost function using a non-regularized least-squares method. We applied our method to Rutford ice stream (RIS), West Antarctica, using a set of 101 multi-track multi-angle COSMO-SkyMed displacement maps generating azimuth and range pixel offsets.

  20. A Multi-scale Finite-frequency Approach to the Inversion of Reciprocal Travel Times for 3-D Velocity Structure beneath Taiwan

    NASA Astrophysics Data System (ADS)

    Chang, Y.; Hung, S.; Kuo, B.; Kuochen, H.

    2012-12-01

    Taiwan is one of the archetypical places for studying the active orogenic process in the world, where the Luzon arc has obliquely collided into the southwest China continental margin since 5 Ma ago. Because of the lack of convincing evidence for the structure in the lithospheric mantle and at even greater depths, several competing models have been proposed for the Taiwan mountain-building process. With the deployment of ocean-bottom seismometers (OBSs) on the seafloor around Taiwan from the TAIGER (TAiwan Integrated GEodynamic Research) and IES seismic experiments, the aperture of the seismic network is greatly extended to improve the depth resolution of tomographic imaging, which is critical to illuminate the nature of the arc-continent collision and accretion in Taiwan. In this study, we use relative travel-time residuals between a collection of teleseismic body wave arrivals to tomographically image the velocity structure beneath Taiwan. In addition to those from common distant earthquakes observed across an array of stations, we take advantage of dense seismicity in the vicinity of Taiwan and the source and receiver reciprocity to augment the data coverage from clustered earthquakes recorded by global stations. As waveforms are dependent of source mechanisms, we carry out the cluster analysis to group the phase arrivals with similar waveforms into clusters and simultaneously determine relative travel-time anomalies in the same cluster accurately by a cross correlation method. The combination of these two datasets would particularly enhance the resolvability of the tomographic models offshore of eastern Taiwan, where the two subduction systems of opposite polarity are taking place and have primarily shaped the present tectonic framework of Taiwan. On the other hand, our inversion adopts an innovation that invokes wavelet-based, multi-scale parameterization and finite-frequency theory. Not only does this approach make full use of frequency-dependent travel

  1. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  2. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  3. 3-D shear wave velocity model of Mexico and South US: bridging seismic networks with ambient noise cross-correlations (C1) and correlation of coda of correlations (C3)

    NASA Astrophysics Data System (ADS)

    Spica, Zack; Perton, Mathieu; Calò, Marco; Legrand, Denis; Córdoba-Montiel, Francisco; Iglesias, Arturo

    2016-09-01

    This work presents an innovative strategy to enhance the resolution of surface wave tomography obtained from ambient noise cross-correlation (C1) by bridging asynchronous seismic networks through the correlation of coda of correlations (C3). Rayleigh wave group dispersion curves show consistent results between synchronous and asynchronous stations. Rayleigh wave group traveltimes are inverted to construct velocity-period maps with unprecedented resolution for a region covering Mexico and the southern United States. The resulting period maps are then used to regionalize dispersion curves in order to obtain local 1-D shear velocity models (VS) of the crust and uppermost mantle in every cell of a grid of 0.4°. The 1-D structures are obtained by iteratively adding layers until reaching a given misfit, and a global tomography model is considered as an input for depths below 150 km. Finally, a high-resolution 3-D VS model is obtained from these inversions. The major structures observed in the 3-D model are in agreement with the tectonic-geodynamic features and with previous regional and local studies. It also offers new insights to understand the present and past tectonic evolution of the region.

  4. Investigation of the dynamics of spiral galaxies on the base of 3D vector velocity field of their gaseous disks reconstructed from observed line-of-sight velocity field.

    NASA Astrophysics Data System (ADS)

    Fridman, A. M.; Khoruzhii, O. V.; Lyakhovich, V. V.; Silchenko, O. K.; Zasov, A. V.; Afanasiev, V. L.; Dodonov, S. N.

    The method is based on Fourier analysis of observed velocity field. The Fourier harmonics are interpreted in the frame of the consensus on the wave nature of spiral arms. We measured the line-of-sight velocity fields in five spiral galaxies. In grand design galaxies NGC 157, NGC 6181 and NGC 3893 we determined with high accuracy all basic parameters: corotation radius, velocity amplitudes in spiral pattern, the rotation velocity curve with account for motions in spiral arms. The analysis of the flocculent galaxy NGC 2841 helped us to understand the nature of the flocculent spirals. The analysis of grand design galaxy NGC 3631 which is seen face on gave the possibility to explain the nature of vertical motion along the disk rotation axis.

  5. Crustal Seismicity and 3-D Velocity Structure in the Principal Cordillera of Central Chile (33- 34.5 S, 69.5-71 W): Implications on Andean Geodynamic and Seismic Hazard

    NASA Astrophysics Data System (ADS)

    Pardo, M.; Monfret, T.; Vera, E.; Yañez, G.; Eisenberg, A.

    2007-12-01

    Based on data from a dense local temporary seismological network, crustal seismicity is characterized, and a 3- D body wave velocity structure is obtained by tomographic inversion down to the subducted slab. In the framework of Fondecyt 1050758, GeoAzur-IRD and ACT-18 projects, 35 broadband and short period instruments, were deployed in the studied zone for 135 days recording in continuous mode. At this zone the Andean active volcanism reappears after a gap of volcanic activity since late Miocene occurring north of 33 S due to the Central Chile flat slab subduction zone. Crustal seismicity in the depth range 0-30 km is well correlated with known geological faults that become now important in the assessment of the regional seismic hazard. This seismicity also clusters around the giant porphyry cooper deposits in the region (Rio Blanco, El Teniente), and are neither related to mine-blasts nor induced by mining activity. Moreover, the local 3-D velocity structure shows that the zone surrounding each deposit is characterized by high Vp/Vs greater than 1.8, which may indicate fluid phases located in the weakest and more fractured zone of the crust. The body wave velocity pattern shown at depth by the local tomography indicates channels of high Vp/Vs connecting the subducted slab with the surface at places where active volcanism is present, suggesting upward migration of hydrous or melted rocks. This pattern agrees with the one observed with a previous regional tomography that includes this zone, while this Vp/Vs pattern tends to be horizontal at the flat slab zone. At depths of 20-25 km, a layer of high Vp/Vs is observed beneath the Andes Cordillera that could be associated to changes in the rheological properties between the upper and lower crust, or to accumulation of magma. The average stress tensor, derived from focal mechanisms, indicate that the Andean zone is under compression in the plate convergence direction.

  6. Europeana and 3D

    NASA Astrophysics Data System (ADS)

    Pletinckx, D.

    2011-09-01

    The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  7. Constraining the Lithospheric Structure of the Central Andes Using P- and S- wave Receiver Functions

    NASA Astrophysics Data System (ADS)

    Ryan, J. C.; Beck, S. L.; Zandt, G.; Wagner, L. S.; Minaya, E.; Tavera, H.

    2014-12-01

    The Central Andean Plateau (CAP) has elevations in excess of 3 km, and is part of the Andean Cordillera that resulted in part from shortening along the western edge of South America as it was compressed between the subducting Nazca plate and underthrusting Brazilian cratonic lithosphere. We calculated P- and S-wave receiver functions for the Central Andean Uplift and Geodynamics of High Topography (CAUGHT) temporary deployment of broadband seismometers in the Bolivian orocline (12°-20°S) region to investigate crustal thickness and lithospheric structure. Migration of the receiver functions is done using common conversion point (CCP) stacks through a 3D shear velocity model from ambient noise tomography (Ward et al., 2013). The P- and S-wave receiver functions provide similar estimates of the depth to Moho under the CAP. Crustal thicknesses include 60-65 km thick crust underneath the Bolivian Altiplano, crust that varies from ~70 km to ~50 km underneath the Eastern Cordillera and Interandean zone, and thins to 50 to 40 km crust in the Subandes and the edge of the foreland. The variable crustal thickness of the Eastern Cordillera and Interandean zone ranges from >70 km associated with the Los Frailes volcanic field at 19°-20°S to ~55 km beneath the 6 km peaks of the Cordillera Real at ~16°S. From our S-wave receiver functions, that have no multiples that can interfere with deeper structure, we also identify structures below the Moho. Along a SW-NE line that runs near La Paz where we have our highest station density, the S-wave CCP receiver-function stacks show a strong negative polarity arrival at a depth of ~120 km from the eastern edge of the Altiplano to the Subandean zone. We suggest this may be a good candidate for the base of the CAP lithosphere. In addition, above this depth the mantle is strongly layered, suggesting that there is not a simple high velocity mantle lithosphere associated with the continental lithosphere underthrusting the Andean orogen

  8. QUANTIFYING UNCERTAINTIES IN GROUND MOTION SIMULATIONS FOR SCENARIO EARTHQUAKES ON THE HAYWARD-RODGERS CREEK FAULT SYSTEM USING THE USGS 3D VELOCITY MODEL AND REALISTIC PSEUDODYNAMIC RUPTURE MODELS

    SciTech Connect

    Rodgers, A; Xie, X

    2008-01-09

    This project seeks to compute ground motions for large (M>6.5) scenario earthquakes on the Hayward Fault using realistic pseudodynamic ruptures, the USGS three-dimensional (3D) velocity model and anelastic finite difference simulations on parallel computers. We will attempt to bound ground motions by performing simulations with suites of stochastic rupture models for a given scenario on a given fault segment. The outcome of this effort will provide the average, spread and range of ground motions that can be expected from likely large earthquake scenarios. The resulting ground motions will be based on first-principles calculations and include the effects of slip heterogeneity, fault geometry and directivity, however, they will be band-limited to relatively low-frequency (< 1 Hz).

  9. P and S wave tomography of Japan subduction zone from joint inversions of local and teleseismic travel times and surface-wave data

    NASA Astrophysics Data System (ADS)

    Liu, Xin; Zhao, Dapeng

    2016-03-01

    We determined P and S wave velocity tomography of the Japan subduction zone down to a depth of 700 km by conducting joint inversions of a large number of high-quality arrival-time data of local earthquakes and teleseismic events which are newly collected for this study. We also determined 2-D phase-velocity images of fundamental mode Rayleigh waves at periods of 20-150 s beneath Japan and the surrounding oceanic regions using amplitude and phase data of teleseismic Rayleigh waves. A detailed 3-D S-wave tomography of the study region is obtained by jointly inverting S-wave arrival times of local and teleseismic events and the Rayleigh-wave phase-velocity data. Our inversion results reveal the subducting Pacific and Philippine Sea slabs clearly as dipping high-velocity zones from a 1-D starting velocity model. Prominent low-velocity (low-V) anomalies are revealed in the mantle wedge above the slabs and in the mantle below the Pacific slab. The distinct velocity contrasts between the subducting slabs and the surrounding mantle reflect significant lateral variations in temperature as well as water content and/or the degree of partial melting. The low-V anomalies in the mantle wedge are attributed to slab dehydration and corner flows in the mantle wedge. A sheet-like low-V zone is revealed under the Pacific slab beneath NE Japan, which may reflect hot upwelling from the deeper mantle and subduction of a plume-fed asthenosphere as well. Our present results indicate that joint inversions of different seismic data are very effective and important for obtaining robust tomographic images of the crust and mantle.

  10. 3-D Attenuation Structure around the SAFOD site, Parkfield, California

    NASA Astrophysics Data System (ADS)

    Harrington, N. L.; Thurber, C. H.; Zhang, H.; Roecker, S.

    2006-12-01

    We are developing models of the 3-D attenuation structure, both Qp and Qs, for a region about 15 km square centered on SAFOD. We are analyzing local earthquake data collected in 2001 and 2002 from the UW/RPI PASO array, the UC-Berkeley HRSN, and USGS seismic network stations around Parkfield. We determine the P- or S-wave t* values for an individual local earthquake for each of the observing stations by fitting observed spectra using a joint inversion for a common corner frequency, low-frequency amplitude, and t*. Within our initial data set, we examine 575 events recorded at up to 111 stations and obtain over 19000 P- wave t* values. We use these t* values in simul2000 and tomoDD to perform the inversion to obtain a 3-D, frequency-independent Qp model of the attenuation structure, using an existing 3-D Vp model and associated event locations. We will use this same procedure to obtain the Qs structure. In our preliminary Qp structure results, we observe a high Qp feature (about 250) at 0-8 km depth on the southwest side of the fault. We associate this feature with the high density, high velocity Salinian basement rocks. We also see a moderate Qp feature (about 150) in the fault zone that encompasses the hypocenters of our events. On the northeast side of the fault, we observe Qp values generally increasing with depth, from 125 at the surface to 200 at 8 km. We will present our final Qp and Qs models, identify major features within the two, and discuss how these features relate to the findings of other geophysical studies in the area (seismic velocity, electrical resistivity, anisotropy). We will discuss how these features relate to the nature of the crust in that area, including the local geology, presence of fluids, fracturing, etc.

  11. 3d-3d correspondence revisited

    DOE PAGES

    Chung, Hee -Joong; Dimofte, Tudor; Gukov, Sergei; ...

    2016-04-21

    In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d N = 2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. As a result, we also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

  12. Joint hypocenter-velocity inversion for the eastern Tennessee seismic zone

    NASA Astrophysics Data System (ADS)

    Vlahovic, Gordana; Powell, Christine A.; Chapman, Martin C.; Sibol, Matthew S.

    1998-03-01

    A joint hypocenter-velocity inversion for the eastern Tennessee seismic zone (ETSZ) has resolved velocity features in basement rock below detached Appalachian thrust sheets. P and S wave arrival times from 492 earthquakes have been inverted for one-(1-D) and three-dimensional (3-D) velocity models to midcrustal depths. The 3-D P and S wave velocity solutions are computed independly and are very similar. In relation to the 1-D model, velocity anomalies range from -8% to +16% in the first layer (upper 5 km) and between ±7% in deeper layers. Prominent velocity anomalies parallel the seismic zone and are consistent from layer to layer. The most persistent anomaly is a low-velocity region that borders the seismic zone to the northwest and is flanked on either side by regions of anomalously high velocity. The New York-Alabama (NY-AL) magnetic lineament coincides with or lies close to the southeast boundary of the prominent velocity low in both the P and S wave velocity images. The spatial coincidence between velocity, gravity, and magnetic gradients suggests that major discontinuities are present in the basement. Relocation in the 3-D velocity model reduced the number of very deep earthquakes (below 20 km) and further accentuated differences in seismogenic properties on either side of the NY-AL lineament. After relocation, most earthquakes occur in a vertically bounded region roughly 30 km wide extending from 4 to 22 km in depth. Most earthquakes occur in regions characterized by either average velocity or small velocity anomalies.

  13. Integrating Mach-Zehnder interferometry with TPIV to measure the time-resolved deformation of a compliant wall along with the 3D velocity field in a turbulent channel flow

    NASA Astrophysics Data System (ADS)

    Zhang, Cao; Miorini, Rinaldo; Katz, Joseph

    2015-11-01

    A system combining tomographic PIV (TPIV) and Mach-Zehnder interferometry (MZI) simultaneously measures the time- resolved 3D flow field and 2D distribution of wall-normal deformation in a turbulent channel flow over a transparent compliant surface. This paper focuses on the experimental techniques and data analysis procedures, but includes sample results. Standard TPIV analysis resolves the log layer of the mean velocity and the linear decrease in total shear stress with distance from the wall. Single-pixel ensemble correlations reveal the buffer layer and top of the viscous sublayer. Analysis of the MZI data consists of two steps, namely critical spatial filtering of interferograms to remove noise and phase demodulation to calculate the surface shape. A new technique to improve the filtration of noise from interferograms based on spatial correlations of small windows is introduced and optimized. Taking advantage of this enhancement, the phase/deformation distribution is calculated directly from arccosines of the intensity, which avoids edge artifacts affecting spectral calculations. Validations using synthetic noisy interferograms indicate that errors associated with correlation-based enhancement are consistently lower and much less sensitive to fringe shape than spectral band-pass filtering. The experimental wavenumber-frequency spectra show that the deformation consists of patterns that are larger than the field of view, surface waves and small-scale patterns. Some of the latter are advected at the freestream velocity, but mostly at 70 % of the freestream, the mean speed at 10 % of the channel half height. Indeed, spatial correlations of the deformation with velocity components peak at this elevation.

  14. Joint Impact Proposal: A complete velocity resolved 3-D [CII] map of the M51 grand-design spiral galaxy: Unraveling the impact of spiral density waves on the evolution of the ISM and star formation.

    NASA Astrophysics Data System (ADS)

    Stutzki, Juergen

    2015-10-01

    We propose to obtain the first complete, velocity resolved [CII] 158um image of the M51 grand-design spiral galaxy with the upGREAT and FIFI-LS instruments on SOFIA. Spiral density waves play a fundamental role on the conversion of atomic to molecular gas, leading to gravitational contraction and thus to star formation. Understanding the impact of spiral density waves on the lifecycle of the interstellar medium and on star formation in galaxies is thus critical for our understanding of galaxy evolution. The [CII] line (in combination with the low-J CO lines and HI 21 cm) is an important tool to diagnose the physical state of the ISM. It can reveal the distribution of the gas that is making a transition between atomic and molecular phases, including the CO-dark H2 gas (hydrogen molecular but carbon ionized, and thus not traced by either HI or CO) in the spiral arms and interarm regions of M51. We will use the high spectral resolution of the upGREAT instrument to resolve spiral arms in velocity, allowing us to study the flow of gas through spiral arms and measure line widths and determine the dynamical state of prominent interarm clouds. The significantly more sensitive FIFI-LS will be used to detect extended faint [CII] emission in the interarm regions and outskirts of the galaxy, including the gas connection to the companion galaxy. The 3-D data cube of velocity-resolved [CII] in this nearby galaxy, combined with the wealth of ancillary data, can be used for a large set of investigations by the broader astronomical community. It will provide for the first time the link between the detailed physical processes in the star-forming ISM in the Milky Way and the average properties of distant external galaxies. This complete map will be also an excellent showcase of SOFIA's capabilities for years to come.

  15. Joint Impact Proposal: A complete velocity resolved 3-D [CII] map of the M51 grand-design spiral galaxy: Unraveling the impact of spiral density waves on the evolution of the ISM and star formation.

    NASA Astrophysics Data System (ADS)

    Pineda, Jorge

    2015-10-01

    We propose to obtain the first complete, velocity resolved [CII] 158um image of the M51 grand-design spiral galaxy with the upGREAT and FIFI-LS instruments on SOFIA. Spiral density waves play a fundamental role on the conversion of atomic to molecular gas, leading to gravitational contraction and thus to star formation. Understanding the impact of spiral density waves on the lifecycle of the interstellar medium and on star formation in galaxies is thus critical for our understanding of galaxy evolution. The [CII] line (in combination with the low-J CO lines and HI 21 cm) is an important tool to diagnose the physical state of the ISM. It can reveal the distribution of the gas that is making a transition between atomic and molecular phases, including the CO-dark H2 gas (hydrogen molecular but carbon ionized, and thus not traced by either HI or CO) in the spiral arms and interarm regions of M51. We will use the high spectral resolution of the upGREAT instrument to resolve spiral arms in velocity, allowing us to study the flow of gas through spiral arms and measure line widths and determine the dynamical state of prominent interarm clouds. The significantly more sensitive FIFI-LS will be used to detect extended faint [CII] emission in the interarm regions and outskirts of the galaxy, including the gas connection to the companion galaxy. The 3-D data cube of velocity--resolved [CII] in this nearby galaxy, combined with the wealth of ancillary data, can be used for a large set of investigations by the broader astronomical community. It will provide for the first time the link between the detailed physical processes in the star-forming ISM in the Milky Way and the average properties of distant external galaxies. This complete map will be also an excellent showcase of SOFIA's capabilities for years to come.

  16. Sedimentary basin effects in Seattle, Washington: Ground-motion observations and 3D simulations

    USGS Publications Warehouse

    Frankel, Arthur; Stephenson, William; Carver, David

    2009-01-01

    Seismograms of local earthquakes recorded in Seattle exhibit surface waves in the Seattle basin and basin-edge focusing of S waves. Spectral ratios of Swaves and later arrivals at 1 Hz for stiff-soil sites in the Seattle basin show a dependence on the direction to the earthquake, with earthquakes to the south and southwest producing higher average amplification. Earthquakes to the southwest typically produce larger basin surface waves relative to S waves than earthquakes to the north and northwest, probably because of the velocity contrast across the Seattle fault along the southern margin of the Seattle basin. S to P conversions are observed for some events and are likely converted at the bottom of the Seattle basin. We model five earthquakes, including the M 6.8 Nisqually earthquake, using 3D finite-difference simulations accurate up to 1 Hz. The simulations reproduce the observed dependence of amplification on the direction to the earthquake. The simulations generally match the timing and character of basin surface waves observed for many events. The 3D simulation for the Nisqually earth-quake produces focusing of S waves along the southern margin of the Seattle basin near the area in west Seattle that experienced increased chimney damage from the earthquake, similar to the results of the higher-frequency 2D simulation reported by Stephenson et al. (2006). Waveforms from the 3D simulations show reasonable agreement with the data at low frequencies (0.2-0.4 Hz) for the Nisqually earthquake and an M 4.8 deep earthquake west of Seattle.

  17. 3D and Education

    NASA Astrophysics Data System (ADS)

    Meulien Ohlmann, Odile

    2013-02-01

    Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

  18. 3D Imaging.

    ERIC Educational Resources Information Center

    Hastings, S. K.

    2002-01-01

    Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)

  19. Waveform inversion for 3-D earth structure using the Direct Solution Method implemented on vector-parallel supercomputer

    NASA Astrophysics Data System (ADS)

    Hara, Tatsuhiko

    2004-08-01

    We implement the Direct Solution Method (DSM) on a vector-parallel supercomputer and show that it is possible to significantly improve its computational efficiency through parallel computing. We apply the parallel DSM calculation to waveform inversion of long period (250-500 s) surface wave data for three-dimensional (3-D) S-wave velocity structure in the upper and uppermost lower mantle. We use a spherical harmonic expansion to represent lateral variation with the maximum angular degree 16. We find significant low velocities under south Pacific hot spots in the transition zone. This is consistent with other seismological studies conducted in the Superplume project, which suggests deep roots of these hot spots. We also perform simultaneous waveform inversion for 3-D S-wave velocity and Q structure. Since resolution for Q is not good, we develop a new technique in which power spectra are used as data for inversion. We find good correlation between long wavelength patterns of Vs and Q in the transition zone such as high Vs and high Q under the western Pacific.

  20. 3D Seismic Imaging over a Potential Collapse Structure

    NASA Astrophysics Data System (ADS)

    Gritto, Roland; O'Connell, Daniel; Elobaid Elnaiem, Ali; Mohamed, Fathelrahman; Sadooni, Fadhil

    2016-04-01

    The Middle-East has seen a recent boom in construction including the planning and development of complete new sub-sections of metropolitan areas. Before planning and construction can commence, however, the development areas need to be investigated to determine their suitability for the planned project. Subsurface parameters such as the type of material (soil/rock), thickness of top soil or rock layers, depth and elastic parameters of basement, for example, comprise important information needed before a decision concerning the suitability of the site for construction can be made. A similar problem arises in environmental impact studies, when subsurface parameters are needed to assess the geological heterogeneity of the subsurface. Environmental impact studies are typically required for each construction project, particularly for the scale of the aforementioned building boom in the Middle East. The current study was conducted in Qatar at the location of a future highway interchange to evaluate a suite of 3D seismic techniques in their effectiveness to interrogate the subsurface for the presence of karst-like collapse structures. The survey comprised an area of approximately 10,000 m2 and consisted of 550 source- and 192 receiver locations. The seismic source was an accelerated weight drop while the geophones consisted of 3-component 10 Hz velocity sensors. At present, we analyzed over 100,000 P-wave phase arrivals and performed high-resolution 3-D tomographic imaging of the shallow subsurface. Furthermore, dispersion analysis of recorded surface waves will be performed to obtain S-wave velocity profiles of the subsurface. Both results, in conjunction with density estimates, will be utilized to determine the elastic moduli of the subsurface rock layers.

  1. AE3D

    SciTech Connect

    Spong, Donald A

    2016-06-20

    AE3D solves for the shear Alfven eigenmodes and eigenfrequencies in a torodal magnetic fusion confinement device. The configuration can be either 2D (e.g. tokamak, reversed field pinch) or 3D (e.g. stellarator, helical reversed field pinch, tokamak with ripple). The equations solved are based on a reduced MHD model and sound wave coupling effects are not currently included.

  2. Laplace-domain waveform modeling and inversion for the 3D acoustic-elastic coupled media

    NASA Astrophysics Data System (ADS)

    Shin, Jungkyun; Shin, Changsoo; Calandra, Henri

    2016-06-01

    Laplace-domain waveform inversion reconstructs long-wavelength subsurface models by using the zero-frequency component of damped seismic signals. Despite the computational advantages of Laplace-domain waveform inversion over conventional frequency-domain waveform inversion, an acoustic assumption and an iterative matrix solver have been used to invert 3D marine datasets to mitigate the intensive computing cost. In this study, we develop a Laplace-domain waveform modeling and inversion algorithm for 3D acoustic-elastic coupled media by using a parallel sparse direct solver library (MUltifrontal Massively Parallel Solver, MUMPS). We precisely simulate a real marine environment by coupling the 3D acoustic and elastic wave equations with the proper boundary condition at the fluid-solid interface. In addition, we can extract the elastic properties of the Earth below the sea bottom from the recorded acoustic pressure datasets. As a matrix solver, the parallel sparse direct solver is used to factorize the non-symmetric impedance matrix in a distributed memory architecture and rapidly solve the wave field for a number of shots by using the lower and upper matrix factors. Using both synthetic datasets and real datasets obtained by a 3D wide azimuth survey, the long-wavelength component of the P-wave and S-wave velocity models is reconstructed and the proposed modeling and inversion algorithm are verified. A cluster of 80 CPU cores is used for this study.

  3. 3-D Seismic Interpretation

    NASA Astrophysics Data System (ADS)

    Moore, Gregory F.

    2009-05-01

    This volume is a brief introduction aimed at those who wish to gain a basic and relatively quick understanding of the interpretation of three-dimensional (3-D) seismic reflection data. The book is well written, clearly illustrated, and easy to follow. Enough elementary mathematics are presented for a basic understanding of seismic methods, but more complex mathematical derivations are avoided. References are listed for readers interested in more advanced explanations. After a brief introduction, the book logically begins with a succinct chapter on modern 3-D seismic data acquisition and processing. Standard 3-D acquisition methods are presented, and an appendix expands on more recent acquisition techniques, such as multiple-azimuth and wide-azimuth acquisition. Although this chapter covers the basics of standard time processing quite well, there is only a single sentence about prestack depth imaging, and anisotropic processing is not mentioned at all, even though both techniques are now becoming standard.

  4. Radiochromic 3D Detectors

    NASA Astrophysics Data System (ADS)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  5. Bootstrapping 3D fermions

    DOE PAGES

    Iliesiu, Luca; Kos, Filip; Poland, David; ...

    2016-03-17

    We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  6. Bootstrapping 3D fermions

    SciTech Connect

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-03-17

    We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  7. Venus in 3D

    NASA Technical Reports Server (NTRS)

    Plaut, Jeffrey J.

    1993-01-01

    Stereographic images of the surface of Venus which enable geologists to reconstruct the details of the planet's evolution are discussed. The 120-meter resolution of these 3D images make it possible to construct digital topographic maps from which precise measurements can be made of the heights, depths, slopes, and volumes of geologic structures.

  8. BEAMS3D Neutral Beam Injection Model

    SciTech Connect

    Lazerson, Samuel

    2014-04-14

    With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.

  9. 3D photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Carson, Jeffrey J. L.; Roumeliotis, Michael; Chaudhary, Govind; Stodilka, Robert Z.; Anastasio, Mark A.

    2010-06-01

    Our group has concentrated on development of a 3D photoacoustic imaging system for biomedical imaging research. The technology employs a sparse parallel detection scheme and specialized reconstruction software to obtain 3D optical images using a single laser pulse. With the technology we have been able to capture 3D movies of translating point targets and rotating line targets. The current limitation of our 3D photoacoustic imaging approach is its inability ability to reconstruct complex objects in the field of view. This is primarily due to the relatively small number of projections used to reconstruct objects. However, in many photoacoustic imaging situations, only a few objects may be present in the field of view and these objects may have very high contrast compared to background. That is, the objects have sparse properties. Therefore, our work had two objectives: (i) to utilize mathematical tools to evaluate 3D photoacoustic imaging performance, and (ii) to test image reconstruction algorithms that prefer sparseness in the reconstructed images. Our approach was to utilize singular value decomposition techniques to study the imaging operator of the system and evaluate the complexity of objects that could potentially be reconstructed. We also compared the performance of two image reconstruction algorithms (algebraic reconstruction and l1-norm techniques) at reconstructing objects of increasing sparseness. We observed that for a 15-element detection scheme, the number of measureable singular vectors representative of the imaging operator was consistent with the demonstrated ability to reconstruct point and line targets in the field of view. We also observed that the l1-norm reconstruction technique, which is known to prefer sparseness in reconstructed images, was superior to the algebraic reconstruction technique. Based on these findings, we concluded (i) that singular value decomposition of the imaging operator provides valuable insight into the capabilities of

  10. 3D ambient noise tomography across the Taiwan Strait: the structure of a magma-poor rifted margin

    NASA Astrophysics Data System (ADS)

    Kuo-Chen, Hao; Chen, Kai-Xun; Brown, Dennis; Li, Qiusheng; Ye, Zhuo; Liang, Wen-Tzong; Wang, Chien-Ying; Yao, Huajian

    2016-04-01

    Rifting along southeastern Eurasia in the Late Cenozoic led to the formation of a magma-poor rifted margin facing the South China Sea to the southeast and the Philippine Sea to the east. Further rifting along the outer part of the margin during the Middle to Late Miocene was accompanied by an extensive episode of intraplate flood volcanism that formed the Penghu Archipelago. Previous geophysical studies in the area of the Strait have focused primarily on the shallow structures of the rift basins and the depth to the Moho. In this study, we present the results of a joint Chinese and Taiwanese 3D ambient noise tomography study from which we calculate the regional-scale 3D S-wave structure of the Taiwan Strait. The S-wave model shows a thinning of the crust beneath the rift basins where, locally, thin high-velocity layers suggest the presence of intrusive bodies. The rift basins and, along the west coast of Taiwan, the foreland basin are imaged as c. 5 to 10 km thick low velocity zones that extend eastward beneath the Taiwan mountain belt. In the upper 10 km of the crust, the basaltic rocks of the Penghu Archipelago are imaged as a high velocity zone that, with depth, becomes a relatively low velocity zone. We interpret this low velocity zone in the lower crust and upper mantle beneath the Penghu Archipelago to image a thermal anomaly related to the still cooling magma feeding system and the melt reservoir area that fed the flood basalts at the surface.

  11. Waveform prediction with travel time model LLNL-G3D assessed by Spectral-Element simulation

    NASA Astrophysics Data System (ADS)

    Morency, C.; Simmons, N. A.; Myers, S. C.; Johannesson, G.; Matzel, E.

    2013-12-01

    Seismic monitoring requires accurate prediction of travel times, amplitudes, and whole waveforms. As a first step towards developing a model that is suited to seismic monitoring, LLNL developed the LLNL-G3D P-wave travel time model (Simmons et al., 2012, JGR) to improve seismic event location accuracy. LLNL-G3D fulfills the need to predict travel times from events occurring anywhere in the globe to stations ranging from local to teleseismic distances. Prediction over this distance range requires explicit inclusion of detailed 3-dimensional structure from Earths surface to the core. An open question is how well a model optimized to fit P-wave travel time data can predict waveforms? We begin to address this question by using the P-wave velocities in LLNL-G3D as a proxy for S-wave velocity and density, then performing waveform simulations via the SPECFEM3D_GLOBE spectral-element code. We assess the ability of LLNL-G3D to predict waveforms and draw comparisons to other 3D models available in SPECFEM3D_GLOBE package and widely used in the scientific community. Although we do not expect the P-wave model to perform as well as waveform based models, we view our effort as a first step towards accurate prediction of time times, amplitudes and full waveforms based on a single model. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  12. Upper mantle shear wave velocity structure of the east Anatolian-Caucasus region

    NASA Astrophysics Data System (ADS)

    Skobeltsyn, Gleb Anatolyevich

    The Eastern Anatolian-Caucasus region is a relatively young part of the Alpine- Himalayan orogenic belt and has been formed as the result of the ongoing continental collision of Arabia and Eurasia. In spite of a number of geological studies that have been conducted in this area, there is still no consensus within the geoscience community about the regional tectonic settings and a model for the late Cenozoic tectonic evolution of the Anatolian Plateau. Knowledge of the upper mantle velocity structure in this region can provide the geological community with important constraints that are crucial for developing an understanding of the regional geology and the processes associated with early stages of mountain building. In the present dissertation, I describe two studies of the regional upper mantle S wave velocity structure. In order to derive the absolute velocity structure of the upper mantle, I have applied surface wave tomography to model Rayleigh wave phase velocities as a function of period. Then I inverted the Rayleigh phase velocities to obtain S wave velocities as a function of depth. The resulted high-resolution 3-D S wave velocity model of the regional upper mantle is characterized by a better depth resolution than any preexisting tomographic models. I also conducted an S wave splitting analysis using traditional methods and developed a two-layer grid search algorithm in order to infer the upper mantle anisotropic structure. The results of the S wave splitting analysis for the stations located in Azerbaijan are the first in the region. (Abstract shortened by ProQuest.).

  13. Microseismic network design assessment based on 3D ray tracing

    NASA Astrophysics Data System (ADS)

    Näsholm, Sven Peter; Wuestefeld, Andreas; Lubrano-Lavadera, Paul; Lang, Dominik; Kaschwich, Tina; Oye, Volker

    2016-04-01

    There is increasing demand on the versatility of microseismic monitoring networks. In early projects, being able to locate any triggers was considered a success. These early successes led to a better understanding of how to extract value from microseismic results. Today operators, regulators, and service providers work closely together in order to find the optimum network design to meet various requirements. In the current study we demonstrate an integrated and streamlined network capability assessment approach. It is intended for use during the microseismic network design process prior to installation. The assessments are derived from 3D ray tracing between a grid of event points and the sensors. Three aspects are discussed: 1) Magnitude of completeness or detection limit; 2) Event location accuracy; and 3) Ground-motion hazard. The network capability parameters 1) and 2) are estimated at all hypothetic event locations and are presented in the form of maps given a seismic sensor coordinate scenario. In addition, the ray tracing traveltimes permit to estimate the point-spread-functions (PSFs) at the event grid points. PSFs are useful in assessing the resolution and focusing capability of the network for stacking-based event location and imaging methods. We estimate the performance for a hypothetical network case with 11 sensors. We consider the well-documented region around the San Andreas Fault Observatory at Depth (SAFOD) located north of Parkfield, California. The ray tracing is done through a detailed velocity model which covers a 26.2 by 21.2 km wide area around the SAFOD drill site with a resolution of 200 m both for the P-and S-wave velocities. Systematic network capability assessment for different sensor site scenarios prior to installation facilitates finding a final design which meets the survey objectives.

  14. Twin Peaks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The two hills in the distance, approximately one to two kilometers away, have been dubbed the 'Twin Peaks' and are of great interest to Pathfinder scientists as objects of future study. 3D glasses are necessary to identify surface detail. The white areas on the left hill, called the 'Ski Run' by scientists, may have been formed by hydrologic processes.

    The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  15. 3D and beyond

    NASA Astrophysics Data System (ADS)

    Fung, Y. C.

    1995-05-01

    This conference on physiology and function covers a wide range of subjects, including the vasculature and blood flow, the flow of gas, water, and blood in the lung, the neurological structure and function, the modeling, and the motion and mechanics of organs. Many technologies are discussed. I believe that the list would include a robotic photographer, to hold the optical equipment in a precisely controlled way to obtain the images for the user. Why are 3D images needed? They are to achieve certain objectives through measurements of some objects. For example, in order to improve performance in sports or beauty of a person, we measure the form, dimensions, appearance, and movements.

  16. 3D Audio System

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Ames Research Center research into virtual reality led to the development of the Convolvotron, a high speed digital audio processing system that delivers three-dimensional sound over headphones. It consists of a two-card set designed for use with a personal computer. The Convolvotron's primary application is presentation of 3D audio signals over headphones. Four independent sound sources are filtered with large time-varying filters that compensate for motion. The perceived location of the sound remains constant. Possible applications are in air traffic control towers or airplane cockpits, hearing and perception research and virtual reality development.

  17. 3D Surgical Simulation

    PubMed Central

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  18. Martian terrain - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    An area of rocky terrain near the landing site of the Sagan Memorial Station can be seen in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  19. 3-D Tomographic Imaging of the Chicxulub Impact Crater: Preliminary Results From EW#0501

    NASA Astrophysics Data System (ADS)

    Surendra, A. T.; Barton, P. J.; Vermeesch, P. M.; Morgan, J. V.; Warner, M. R.; Gulick, S. P.; Christeson, G. L.; Urrutia-Fucugauchi, J.; Rebolledo-Vieyra, M.; Melosh, H. J.; McDonald, M. A.; Goldin, T.; Mendoza, K.

    2005-05-01

    The Chicxulub impact structure provides a unique opportunity to investigate the sub-surface morphology of large craters on Earth and other planets. The structure of the crater interior is still poorly known and there is much uncertainty over the sequence of events by which these large craters form and the magnitude of the subsequent catastrophic environmental effects. In early 2005, a reflection-refraction survey aboard the R/V Maurice Ewing imaged the deep structure of the Chicxulub impact. We present wide-angle data collected by a 3-D grid of 50 ocean bottom seismometers (OBSs), 86 three-component land stations and a 6 km long hydrophone streamer. The OBS grid, designed to image the peak ring and underlying structure of the northwestern quadrant of the crater, recorded shots from several seismic profiles in various orientations. Many of these profiles extended past the crater rim imaging to the base of the crust. Travel-time picks from this dataset, combined with existing 1996 data, will be inverted using the JIVE3-D tomographic inversion program to create a fully 3-D velocity model of the crater interior. The interpretation of the velocity model will focus on the morphology of the peak ring and the central uplift, and the distribution of breccia and suevite (an impact related breccia/melt) in the centre of the crater. We will calculate the Poisson's ratio for different areas of the crater using both the P-wave velocity model and S-wave arrivals, including those from the 1996 land station data. Comparisons of these values with measurements on the Yaxcopoil-1 core taken from within the crater provide ground-truth for our tomographic model. The contrast in Poisson's ratio between areas of suevite and the surrounding rock further constrain the distribution of breccia and suevite.

  20. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  1. 3-D crustal structure along the North Anatolian Fault Zone in north-central Anatolia revealed by local earthquake tomography

    NASA Astrophysics Data System (ADS)

    Yolsal-Ćevikbilen, Seda; Biryol, C. Berk; Beck, Susan; Zandt, George; Taymaz, Tuncay; Adıyaman, Hande E.; Özacar, A. Arda

    2012-03-01

    3-D P-wave velocity structure and Vp/Vs variations in the crust along the North Anatolian Fault Zone (NAFZ) in north-central Anatolia were investigated by the inversion of local P- and S-wave traveltimes, to gain a better understanding of the seismological characteristics of the region. The 3-D local earthquake tomography inversions included 5444 P- and 3200 S-wave readings obtained from 168 well-located earthquakes between 2006 January and 2008 May. Dense ray coverage yields good resolution, particularly in the central part of the study area. The 3-D Vp and Vp/Vs tomographic images reveal clear correlations with both the surface geology and significant tectonic units in the region. We observed the lower limit of the seismogenic zone for north-central Anatolia at 15 km depth. Final earthquake locations display a distributed pattern throughout the study area, with most of the earthquakes occurring on the major splays of the NAFZ, rather than its master strand. We identify three major high-velocity blocks in the mid-crust separated by the İzmir-Ankara-Erzincan Suture and interpret these blocks to be continental basement fragments that were accreted onto the margin following the closure of Neo-Tethyan Ocean. These basement blocks may have in part influenced the rupture propagations of the historical 1939, 1942 and 1943 earthquakes. In addition, large variations in the Vp/Vs ratio in the mid-crust were observed and have been correlated with the varying fluid contents of the existing lithologies and related tectonic structures.

  2. Scientific Objectives of Small Carry-on Impactor (SCI) and Deployable Camera 3 Digital (DCAM3-D): Observation of an Ejecta Curtain and a Crater Formed on the Surface of Ryugu by an Artificial High-Velocity Impact

    NASA Astrophysics Data System (ADS)

    Arakawa, M.; Wada, K.; Saiki, T.; Kadono, T.; Takagi, Y.; Shirai, K.; Okamoto, C.; Yano, H.; Hayakawa, M.; Nakazawa, S.; Hirata, N.; Kobayashi, M.; Michel, P.; Jutzi, M.; Imamura, H.; Ogawa, K.; Sakatani, N.; Iijima, Y.; Honda, R.; Ishibashi, K.; Hayakawa, H.; Sawada, H.

    2016-10-01

    The Small Carry-on Impactor (SCI) equipped on Hayabusa2 was developed to produce an artificial impact crater on the primitive Near-Earth Asteroid (NEA) 162173 Ryugu (Ryugu) in order to explore the asteroid subsurface material unaffected by space weathering and thermal alteration by solar radiation. An exposed fresh surface by the impactor and/or the ejecta deposit excavated from the crater will be observed by remote sensing instruments, and a subsurface fresh sample of the asteroid will be collected there. The SCI impact experiment will be observed by a Deployable CAMera 3-D (DCAM3-D) at a distance of ˜1 km from the impact point, and the time evolution of the ejecta curtain will be observed by this camera to confirm the impact point on the asteroid surface. As a result of the observation of the ejecta curtain by DCAM3-D and the crater morphology by onboard cameras, the subsurface structure and the physical properties of the constituting materials will be derived from crater scaling laws. Moreover, the SCI experiment on Ryugu gives us a precious opportunity to clarify effects of microgravity on the cratering process and to validate numerical simulations and models of the cratering process.

  3. Intraoral 3D scanner

    NASA Astrophysics Data System (ADS)

    Kühmstedt, Peter; Bräuer-Burchardt, Christian; Munkelt, Christoph; Heinze, Matthias; Palme, Martin; Schmidt, Ingo; Hintersehr, Josef; Notni, Gunther

    2007-09-01

    Here a new set-up of a 3D-scanning system for CAD/CAM in dental industry is proposed. The system is designed for direct scanning of the dental preparations within the mouth. The measuring process is based on phase correlation technique in combination with fast fringe projection in a stereo arrangement. The novelty in the approach is characterized by the following features: A phase correlation between the phase values of the images of two cameras is used for the co-ordinate calculation. This works contrary to the usage of only phase values (phasogrammetry) or classical triangulation (phase values and camera image co-ordinate values) for the determination of the co-ordinates. The main advantage of the method is that the absolute value of the phase at each point does not directly determine the coordinate. Thus errors in the determination of the co-ordinates are prevented. Furthermore, using the epipolar geometry of the stereo-like arrangement the phase unwrapping problem of fringe analysis can be solved. The endoscope like measurement system contains one projection and two camera channels for illumination and observation of the object, respectively. The new system has a measurement field of nearly 25mm × 15mm. The user can measure two or three teeth at one time. So the system can by used for scanning of single tooth up to bridges preparations. In the paper the first realization of the intraoral scanner is described.

  4. 'Diamond' in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  5. Prominent rocks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Many prominent rocks near the Sagan Memorial Station are featured in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. Wedge is at lower left; Shark, Half-Dome, and Pumpkin are at center. Flat Top, about four inches high, is at lower right. The horizon in the distance is one to two kilometers away.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  6. Supernova Remnant in 3-D

    NASA Technical Reports Server (NTRS)

    2009-01-01

    wavelengths. Since the amount of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through.

    The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave.

    This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron.

    High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these

  7. 3D crustal structure of the Alpine belt and foreland basins as imaged by ambient-noise surface wave

    NASA Astrophysics Data System (ADS)

    Molinari, Irene; Morelli, Andrea; Cardi, Riccardo; Boschi, Lapo; Poli, Piero; Kissling, Edi

    2016-04-01

    We derive a 3-D crustal structure (S wave velocity) underneath northern Italy and the wider Alpine region, from an extensive data set of measurements of Rayleigh-wave phase- and group-velocities from ambient noise correlation among all seismographic stations available to date in the region, via a constrained tomographic inversion made to honor detailed active source reflection/refraction profiles and other geological information. We first derive a regional-scale surface wave tomography from ambient-noise-based phase- and group- surface wave velocity observations (Verbeke et al., 2012). Our regional 3D model (Molinari et al., 2015) shows the low velocity area beneath the Po Plain and the Molasse basin; the contrast between the low-velocity crust of the Adriatic domain and the high-velocity crust of the Tyrrhenian domain is clearly seen, as well as an almost uniform crystalline crust beneath the Alpine belt. However, higher frequency data can be exploited to achieve higher resolution images of the Po Plain and Alpine foreland 3D crustal structure. We collected and analyze one year of noise records (2011) of ~100 North Italy seismic broadband stations, we derive the Green functions between each couple of stations and we measure the phase- and group-Rayleigh wave velocity. We conduct a suite of linear least squares inversion of both phase- and group-velocity data, resulting in 2-D maps of Rayleigh-wave phase and group velocity at periods between 3 and 40s with a resolution of 0.1x0.1 degrees. The maps are then inverted to get the 3D structure with unprecedented details. We present here our results, we compare them with other studies, and we discuss geological/geodynamical implications. We believe that such a model stands for the most up-to-date seismological information on the crustal structure of the Alpine belt and foreland basins, and it can represent a reliable reference for further, more detailed, studies to come, based on the high seismograph station density

  8. Rubber Impact on 3D Textile Composites

    NASA Astrophysics Data System (ADS)

    Heimbs, Sebastian; Van Den Broucke, Björn; Duplessis Kergomard, Yann; Dau, Frederic; Malherbe, Benoit

    2012-06-01

    A low velocity impact study of aircraft tire rubber on 3D textile-reinforced composite plates was performed experimentally and numerically. In contrast to regular unidirectional composite laminates, no delaminations occur in such a 3D textile composite. Yarn decohesions, matrix cracks and yarn ruptures have been identified as the major damage mechanisms under impact load. An increase in the number of 3D warp yarns is proposed to improve the impact damage resistance. The characteristic of a rubber impact is the high amount of elastic energy stored in the impactor during impact, which was more than 90% of the initial kinetic energy. This large geometrical deformation of the rubber during impact leads to a less localised loading of the target structure and poses great challenges for the numerical modelling. A hyperelastic Mooney-Rivlin constitutive law was used in Abaqus/Explicit based on a step-by-step validation with static rubber compression tests and low velocity impact tests on aluminium plates. Simulation models of the textile weave were developed on the meso- and macro-scale. The final correlation between impact simulation results on 3D textile-reinforced composite plates and impact test data was promising, highlighting the potential of such numerical simulation tools.

  9. Identification and mitigation of T-S waves using localized dynamic surface modification

    NASA Astrophysics Data System (ADS)

    Amitay, Michael; Tuna, Burak A.; Dell'Orso, Haley

    2016-06-01

    The control of transition from a laminar to a turbulent flow over a flat plate using localized dynamic surface modifications was explored experimentally in Rensselaer Polytechnic Institute's subsonic wind tunnel. Dynamic surface modification, via a pair of Piezoelectrically Driven Oscillating Surface (PDOS) actuators, was used to excite and control the T-S wave over a flat plate. Creating an upstream, localized small disturbance at the most amplified frequency of fact = 250 Hz led to phase-locking the T-S wave. This enabled observation of the excited T-S wave using phase-locked stereoscopic particle image velocimetry. The growth of the T-S wave as it moved downstream was also measured using this technique (25% growth over four wavelengths of the excited wave). Activation of a downstream PDOS actuator (in addition to the upstream PDOS) at the appropriate amplitude and phase shift resulted in attenuation of the peak amplitude of the coherent velocity fluctuations (by up to 68%) and a substantial reduction of the degree of coherence of the T-S wave. Since the PDOS actuators used in this work were localized, the effect of the control strategy was confined to the region directly downstream of the PDOS actuator.

  10. Testing long-period ground-motion simulations of scenario earthquakes using the Mw 7.2 El Mayor-Cucapah mainshock: Evaluation of finite-fault rupture characterization and 3D seismic velocity models

    USGS Publications Warehouse

    Graves, Robert W.; Aagaard, Brad T.

    2011-01-01

    Using a suite of five hypothetical finite-fault rupture models, we test the ability of long-period (T>2.0 s) ground-motion simulations of scenario earthquakes to produce waveforms throughout southern California consistent with those recorded during the 4 April 2010 Mw 7.2 El Mayor-Cucapah earthquake. The hypothetical ruptures are generated using the methodology proposed by Graves and Pitarka (2010) and require, as inputs, only a general description of the fault location and geometry, event magnitude, and hypocenter, as would be done for a scenario event. For each rupture model, two Southern California Earthquake Center three-dimensional community seismic velocity models (CVM-4m and CVM-H62) are used, resulting in a total of 10 ground-motion simulations, which we compare with recorded ground motions. While the details of the motions vary across the simulations, the median levels match the observed peak ground velocities reasonably well, with the standard deviation of the residuals generally within 50% of the median. Simulations with the CVM-4m model yield somewhat lower variance than those with the CVM-H62 model. Both models tend to overpredict motions in the San Diego region and underpredict motions in the Mojave desert. Within the greater Los Angeles basin, the CVM-4m model generally matches the level of observed motions, whereas the CVM-H62 model tends to overpredict the motions, particularly in the southern portion of the basin. The variance in the peak velocity residuals is lowest for a rupture that has significant shallow slip (<5 km depth), whereas the variance in the residuals is greatest for ruptures with large asperities below 10 km depth. Overall, these results are encouraging and provide confidence in the predictive capabilities of the simulation methodology, while also suggesting some regions in which the seismic velocity models may need improvement.

  11. Estimating Moho depth utilizing S-wave receiver functions

    NASA Astrophysics Data System (ADS)

    Ceylan, S.; Rychert, C.; Harmon, N.

    2014-12-01

    H-k stacking method [Zhu and Kanamori, 2000] is a widely used grid search technique for estimating the Moho depth (H) and Vp/Vs (k) beneath a given station. The H-k surface reaches a maximum when the optimum H and k values are used, which is assumed to be the average crustal structure beneath the seismic station. In general, the method is employed in conjunction with P-wave receiver functions. Here, we investigate the usability of H-k stacking method with S-to-P (Sp) conversions and S-wave reverberations within the crust, employing an extended multi-taper deconvolution. We apply the method to southern California, using data recorded between 1990-2011. We compare results with those of prior studies that used P-to-S (Ps) conversions [Zhu and Kanamori, 2000; Yan and Clayton, 2007], applying a smoothing length of 0.5 degrees to reflect lateral Sp sensitivity. P-waves have better potential to resolve lateral variations in Moho depth owing to the higher frequency content and the geometry of Ps ray path. Our results from Sp conversions are in broad agreement with those from Ps, affirming that S-wave receiver functions can be used in conjunction with the H-k stacking method. Consistent with the P-wave receiver function results, crust is thinner beneath the central Transverse Range (30 km) with respect to eastern Transverse Range (33 km) and Peninsular Region (35 km). Our Moho depth observations (35 km) are more compatible with those of Yan and Clayton [2007] (~35 km) than Zhu and Kanamori [2000] (~30 km) beneath Sierra Nevada, most probably due to a larger data set this study and Yan and Clayton [2007] use. Also, results from this study are deeper than those from Ps for the Salton Trough (30-35 km vs. 25 km). In this case, broad receiver function waveform characteristics suggest a more gradual impedance change across the Moho discontinuity and/or a multi-layered crust. We suggest that a combination of P- and S-wave receiver functions can yield more robust crustal thickness

  12. Double-difference relocations and spectral ratio analysis of volcanic seismic events in the Mount St. Helens crater using a 3D velocity model suggest slip events under the new dome with constant stress-drop scaling.

    NASA Astrophysics Data System (ADS)

    Harrington, R. M.; Kwiatek, G.; Moran, S. C.

    2014-12-01

    Shallow low frequency seismic events are common features associated with restless and erupting volcanoes. The physical mechanisms generating their characteristic low frequency, and often extended duration signals remain poorly understood. Here we present new double-difference relocations and spectral scaling of a group of ~400 shallow low-frequency seismic events occurring within the Mount St. Helens edifice during its 2004-2008 dome-building eruption, as recorded by a temporary seismic array for a month within the crater in 2006. Relocation results suggest that the majority of earthquakes occurred in the center of the crater close to the vent at depths < 500 m, with some events potentially locating under the new dome but ~200-300m southwest of the vent. Low-frequency events exhibit moment-corner frequency scaling roughly consistent with a constant static stress-drop, similar to tectonic earthquakes occurring elsewhere in shallow crustal faults. The scaling suggests that the ~400 events result from stick-slip behavior, and that the low frequency character of the waveforms may result from a combination of path effects and slow rupture speeds. For relocation, we divide the 400 events into eight families based on waveform similarity, and use a subset of nearly 40 earthquakes with clear first arrivals ranging in moment magnitude from 0.4 - 1.8 to calculate hypocenters. We then relocate these events using a double-difference method with a three-dimensional velocity model of the edifice from Waite and Moran (2009). The relocated events are then used to estimate source parameters of the remaining earthquakes via a spectral ratio technique. Spectral corner frequency estimations based on this spectral ratio approach produce stress-drop values of ~1 MPa assuming a shear-wave velocity of 1500 m/s. The estimations also indicate a constant stress-drop scaling for all events, with two event families having lower estimated stress drops of ~0.1 MPa. While localized lithological

  13. Geological structure analysis in Central Java using travel time tomography technique of S waves

    NASA Astrophysics Data System (ADS)

    Palupi, I. R.; Raharjo, W.; Nurdian, S. W.; Giamboro, W. S.; Santoso, A.

    2016-11-01

    Java is one of the islands in Indonesia that is prone to the earthquakes, in south of Java, there is the Australian Plate move to the Java island and press with perpendicular direction. This plate movement formed subduction zone and cause earthquakes. The earthquake is the release of energy due to the sudden movement of the plates. When an earthquake occurs, the energy is released and record by seismometers in the waveform. The first wave recorded is called the P waves (primary) and the next wave is called S waves (secondary). Both of these waves have different characteristics in terms of propagation and direction of movement. S wave is composed of waves of Rayleigh and Love waves, with each direction of movement of the vertical and horizontal, subsurface imaging by using S wave tomography technique can describe the type of the S wave through the medium. The variation of wave velocity under Central Java (esearch area) is ranging from -10% to 10% at the depth of 20, 30 and 40 km, the velocity decrease with the depth increase. Moho discontinuity is lies in the depth of 32 km under the crust, it is indicates there is strong heterogenity in Moho.

  14. P and S-wave tomographic images for the PASSCAL experiments

    NASA Astrophysics Data System (ADS)

    Yuan, H.; Dueker, K.

    2001-12-01

    We present teleseismic P and S-wave tomographic images down to 400 Km for the PASSCAL CD-ROM teleseismic experiment. Our aim is to investigate the structural variations across the Archean-Proterozoic Cheyenne Belt (the North line) and across the Proterozoic-Proterozoic Jemez volcanic lineament (the South line). A full year of teleseismic P and S-wave data was collected from 48 PASSCAL broadband 3-component instruments. S phases were rotated to the direction of maximum linear polarization. A multi-channel cross correlation technique was used to measure the arrival times. We picked 1400 travel-time residuals for the teleseismic S, ScS and SKS phases and 2000 for P. An iterative LSQR matrix solver with Laplacian regulation was applied to invert the data for P and S wave images. Our preliminary results show large peak-to-peak teleseismic residuals, i.e., 2 sec P-time variations and 5 sec S-wave variations. The peak-to-peak S velocity difference reaches 12%. In the CD-ROM North line a fast anomaly appears north of CB, which is consistent with the cold, stable Archean craton. To the south this feature vanishes across the Cheyenne Belt (N 41.25 deg). The south line shows a large low velocity zone extending to 200 km beneath the Jemez volcanic lineament. The P-wave and S-wave images are highly correlated with a dnVp/dlnVs ratio of about 2. Images from two different PASSCAL experiments, the Lodore and Laramie array, share the complexities of the seismic velocity variation beneath the CD-ROM transects. A joint inversion of the P and S and a delta t-star data are proposed to further constrain the thermal state and composition state of the active upper mantle beneath the Wyoming, Colorado and New Mexico regions.

  15. 3D Spectroscopy in Astronomy

    NASA Astrophysics Data System (ADS)

    Mediavilla, Evencio; Arribas, Santiago; Roth, Martin; Cepa-Nogué, Jordi; Sánchez, Francisco

    2011-09-01

    Preface; Acknowledgements; 1. Introductory review and technical approaches Martin M. Roth; 2. Observational procedures and data reduction James E. H. Turner; 3. 3D Spectroscopy instrumentation M. A. Bershady; 4. Analysis of 3D data Pierre Ferruit; 5. Science motivation for IFS and galactic studies F. Eisenhauer; 6. Extragalactic studies and future IFS science Luis Colina; 7. Tutorials: how to handle 3D spectroscopy data Sebastian F. Sánchez, Begona García-Lorenzo and Arlette Pécontal-Rousset.

  16. Spherical 3D isotropic wavelets

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Rassat, A.; Starck, J.-L.

    2012-04-01

    Context. Future cosmological surveys will provide 3D large scale structure maps with large sky coverage, for which a 3D spherical Fourier-Bessel (SFB) analysis in spherical coordinates is natural. Wavelets are particularly well-suited to the analysis and denoising of cosmological data, but a spherical 3D isotropic wavelet transform does not currently exist to analyse spherical 3D data. Aims: The aim of this paper is to present a new formalism for a spherical 3D isotropic wavelet, i.e. one based on the SFB decomposition of a 3D field and accompany the formalism with a public code to perform wavelet transforms. Methods: We describe a new 3D isotropic spherical wavelet decomposition based on the undecimated wavelet transform (UWT) described in Starck et al. (2006). We also present a new fast discrete spherical Fourier-Bessel transform (DSFBT) based on both a discrete Bessel transform and the HEALPIX angular pixelisation scheme. We test the 3D wavelet transform and as a toy-application, apply a denoising algorithm in wavelet space to the Virgo large box cosmological simulations and find we can successfully remove noise without much loss to the large scale structure. Results: We have described a new spherical 3D isotropic wavelet transform, ideally suited to analyse and denoise future 3D spherical cosmological surveys, which uses a novel DSFBT. We illustrate its potential use for denoising using a toy model. All the algorithms presented in this paper are available for download as a public code called MRS3D at http://jstarck.free.fr/mrs3d.html

  17. 3D Elevation Program—Virtual USA in 3D

    USGS Publications Warehouse

    Lukas, Vicki; Stoker, J.M.

    2016-04-14

    The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.  

  18. Ambient noise tomography of the Pyrenees and the surrounding regions: inversion for a 3-D Vs model in the presence of a very heterogeneous crust

    NASA Astrophysics Data System (ADS)

    Macquet, Marie; Paul, Anne; Pedersen, Helle A.; Villaseñor, Antonio; Chevrot, Sébastien; Sylvander, Matthieu; Wolyniec, David; Pyrope Working Group

    2014-10-01

    The lithospheric architecture of the Pyrenees is still uncertain and highly debated. Here, we provide new constraints from a high-resolution 3-D S-wave velocity model of the Pyrenees and the adjacent foreland basins. This model is obtained from ambient noise tomography on records of temporary and permanent seismic arrays installed in southwestern France and northern Spain. We first computed group velocity maps for Rayleigh waves in the 5 to 55 s period range using noise correlation stacks at 1500-8500 station pairs. As the crust is very heterogeneous, poor results were obtained using a single starting model in a linearized inversion of group velocity dispersion curves for the shear wave structure. We therefore built a starting model for each grid node by full exploration of the model space. The resulting 3-D shear wave velocity model is compared to data from previous geophysical studies as a validation test. Despite the poor sensitivity of surface waves to seismic discontinuities, the geometry of the top of the basement and the Moho depth are retrieved well, except along the Cantabrian coast. Major reflectors of the ECORS deep seismic sounding profiles in the central and western Pyrenees coincide with sharp velocity gradients in our velocity model. We retrieve the difference between the thicker Iberian crust and the thinner European crust, the presence of low-velocity material of the Iberian crust underthrust beneath the European crust in the central Pyrenees, and the structural dissymmetry between the South Pyrenean Zone and the North Pyrenean Zone at the shallow crustal level. In the Labourd-Mauléon-Arzacq region (western Pyrenees), there is a high S-wave velocity anomaly at 20-30 km in depth, which might explain the positive Bouguer anomaly of the Labourd Massif. This high-velocity lower crust, which is also detected beneath the Parentis area, might be an imprint of the Albian-Aptian rifting phase. The southeastern part of the Massif Central has an unusual

  19. PLOT3D/AMES, DEC VAX VMS VERSION USING DISSPLA (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  20. PLOT3D/AMES, DEC VAX VMS VERSION USING DISSPLA (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P. G.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  1. How 3-D, 3-C seismic characterized a carbonate reservoir

    SciTech Connect

    Arestad, J.F.; Mattocks, B.W.; Davis, T.L.; Benson, R.D.

    1995-04-01

    The Reservoir Characterization Project (RCP) at the Colorado School of Mines has pioneered research into 3-D, 3-C (multicomponent) reflection seismology for nearly a decade utilizing both P-wave and S-wave sources. Multicomponent-seismic surveys provide significantly more information about petroleum reservoirs than compressional-wave surveys. Initial 3-D, 3-C surveys acquired by RCP were targeted at characterizing naturally fractured reservoirs. The current phase of the project is oriented towards utilizing shear waves to discriminate lithologic and diagenetic changes within stratigraphic reservoirs where compressional-seismic data has not be effective. The Joffre field, Nisku reservoir, is the site of RCP`s ongoing multidisciplinary research effort in Western Canada. The research team is directed by Colorado School of Mines faculty with graduate team members from geology, geophysics and petroleum engineering departments. While this study is still in progress, some key findings and directions of this research are reported here. The following topics will be discussed: Joffre field 3-D, 3-C survey; compressional wave 3-D technique; shear-wave 3-D technique; converted-wave 3-D technique; reservoir characterization, and future directions.

  2. 3D World Building System

    ScienceCinema

    None

    2016-07-12

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  3. 3D Buckligami: Digital Matter

    NASA Astrophysics Data System (ADS)

    van Hecke, Martin; de Reus, Koen; Florijn, Bastiaan; Coulais, Corentin

    2014-03-01

    We present a class of elastic structures which exhibit collective buckling in 3D, and create these by a 3D printing/moulding technique. Our structures consist of cubic lattice of anisotropic unit cells, and we show that their mechanical properties are programmable via the orientation of these unit cells.

  4. 3D World Building System

    SciTech Connect

    2013-10-30

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  5. LLNL-Earth3D

    SciTech Connect

    2013-10-01

    Earth3D is a computer code designed to allow fast calculation of seismic rays and travel times through a 3D model of the Earth. LLNL is using this for earthquake location and global tomography efforts and such codes are of great interest to the Earth Science community.

  6. Market study: 3-D eyetracker

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A market study of a proposed version of a 3-D eyetracker for initial use at NASA's Ames Research Center was made. The commercialization potential of a simplified, less expensive 3-D eyetracker was ascertained. Primary focus on present and potential users of eyetrackers, as well as present and potential manufacturers has provided an effective means of analyzing the prospects for commercialization.

  7. Euro3D Science Conference

    NASA Astrophysics Data System (ADS)

    Walsh, J. R.

    2004-02-01

    The Euro3D RTN is an EU funded Research Training Network to foster the exploitation of 3D spectroscopy in Europe. 3D spectroscopy is a general term for spectroscopy of an area of the sky and derives its name from its two spatial + one spectral dimensions. There are an increasing number of instruments which use integral field devices to achieve spectroscopy of an area of the sky, either using lens arrays, optical fibres or image slicers, to pack spectra of multiple pixels on the sky (``spaxels'') onto a 2D detector. On account of the large volume of data and the special methods required to reduce and analyse 3D data, there are only a few centres of expertise and these are mostly involved with instrument developments. There is a perceived lack of expertise in 3D spectroscopy spread though the astronomical community and its use in the armoury of the observational astronomer is viewed as being highly specialised. For precisely this reason the Euro3D RTN was proposed to train young researchers in this area and develop user tools to widen the experience with this particular type of data in Europe. The Euro3D RTN is coordinated by Martin M. Roth (Astrophysikalisches Institut Potsdam) and has been running since July 2002. The first Euro3D science conference was held in Cambridge, UK from 22 to 23 May 2003. The main emphasis of the conference was, in keeping with the RTN, to expose the work of the young post-docs who are funded by the RTN. In addition the team members from the eleven European institutes involved in Euro3D also presented instrumental and observational developments. The conference was organized by Andy Bunker and held at the Institute of Astronomy. There were over thirty participants and 26 talks covered the whole range of application of 3D techniques. The science ranged from Galactic planetary nebulae and globular clusters to kinematics of nearby galaxies out to objects at high redshift. Several talks were devoted to reporting recent observations with newly

  8. PLOT3D/AMES, GENERIC UNIX VERSION USING DISSPLA (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  9. PLOT3D/AMES, GENERIC UNIX VERSION USING DISSPLA (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  10. 3D vision system assessment

    NASA Astrophysics Data System (ADS)

    Pezzaniti, J. Larry; Edmondson, Richard; Vaden, Justin; Hyatt, Bryan; Chenault, David B.; Kingston, David; Geulen, Vanilynmae; Newell, Scott; Pettijohn, Brad

    2009-02-01

    In this paper, we report on the development of a 3D vision system consisting of a flat panel stereoscopic display and auto-converging stereo camera and an assessment of the system's use for robotic driving, manipulation, and surveillance operations. The 3D vision system was integrated onto a Talon Robot and Operator Control Unit (OCU) such that direct comparisons of the performance of a number of test subjects using 2D and 3D vision systems were possible. A number of representative scenarios were developed to determine which tasks benefited most from the added depth perception and to understand when the 3D vision system hindered understanding of the scene. Two tests were conducted at Fort Leonard Wood, MO with noncommissioned officers ranked Staff Sergeant and Sergeant First Class. The scenarios; the test planning, approach and protocols; the data analysis; and the resulting performance assessment of the 3D vision system are reported.

  11. 3D printing in dentistry.

    PubMed

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery.

  12. PLOT3D user's manual

    NASA Technical Reports Server (NTRS)

    Walatka, Pamela P.; Buning, Pieter G.; Pierce, Larry; Elson, Patricia A.

    1990-01-01

    PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files.

  13. P and S wave responses of bacterial biopolymer formation in unconsolidated porous media

    NASA Astrophysics Data System (ADS)

    Noh, Dong-Hwa; Ajo-Franklin, Jonathan B.; Kwon, Tae-Hyuk; Muhunthan, Balasingam

    2016-04-01

    This study investigated the P and S wave responses and permeability reduction during bacterial biopolymer formation in unconsolidated porous media. Column experiments with fine sands, where the model bacteria Leuconostoc mesenteroides were stimulated to produce insoluble biopolymer, were conducted while monitoring changes in permeability and P and S wave responses. The bacterial biopolymer reduced the permeability by more than 1 order of magnitude, occupying ~10% pore volume after 38 days of growth. This substantial reduction was attributed to the bacterial biopolymer with complex internal structures accumulated at pore throats. S wave velocity (VS) increased by more than ~50% during biopolymer accumulation; this indicated that the bacterial biopolymer caused a certain level of stiffening effect on shear modulus of the unconsolidated sediment matrix at low confining stress conditions. Whereas replacing pore water by insoluble biopolymer was observed to cause minimal changes in P wave velocity (VP) due to the low elastic moduli of insoluble biopolymer. The spectral ratio analyses revealed that the biopolymer formation caused a ~50-80% increase in P wave attenuation (1/QP) at the both ultrasonic and subultrasonic frequency ranges, at hundreds of kHz and tens of kHz, respectively, and a ~50-60% increase in S wave attenuation (1/QS) in the frequency band of several kHz. Our results reveal that in situ biopolymer formation and the resulting permeability reduction can be effectively monitored by using P and S wave attenuation in the ultrasonic and subultrasonic frequency ranges. This suggests that field monitoring using seismic logging techniques, including time-lapse dipole sonic logging, may be possible.

  14. PLOT3D/AMES, UNIX SUPERCOMPUTER AND SGI IRIS VERSION (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  15. PLOT3D/AMES, UNIX SUPERCOMPUTER AND SGI IRIS VERSION (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  16. Unassisted 3D camera calibration

    NASA Astrophysics Data System (ADS)

    Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.

    2012-03-01

    With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.

  17. Estimation of gas-hydrate distribution from 3-D seismic data in a small area of the Ulleung Basin, East Sea

    NASA Astrophysics Data System (ADS)

    Yi, Bo-Yeon; Kang, Nyeon-Keon; Yoo, Dong-Geun; Lee, Gwang-Hoon

    2014-05-01

    We estimated the gas-hydrate resource in a small (5 km x 5 km) area of the Ulleung Basin, East Sea from 3-D seismic and well-log data together with core measurement data, using seismic inversion and multi-attribute transform techniques. Multi-attribute transform technique finds the relationship between measured logs and the combination of the seismic attributes and various post-stack and pre-stack attributes computed from inversion. First, the gas-hydrate saturation and S-wave velocity at the wells were estimated from the simplified three-phase Biot-type equation (STPBE). The core X-ray diffraction data were used to compute the elastic properties of solid components of sediment, which are the key input parameters to the STPBE. Next, simultaneous pre-stack inversion was carried out to obtain P-wave impedance, S-wave impedance, density and lambda-mu-rho attributes. Then, the porosity and gas-hydrate saturation of 3-D seismic volume were predicted from multi-attribute transform. Finally, the gas-hydrate resource was computed by the multiplication of the porosity and gas-hydrate saturation volumes.

  18. 3D Scan Systems Integration

    DTIC Science & Technology

    2007-11-02

    AGENCY USE ONLY (Leave Blank) 2. REPORT DATE 5 Feb 98 4. TITLE AND SUBTITLE 3D Scan Systems Integration REPORT TYPE AND DATES COVERED...2-89) Prescribed by ANSI Std. Z39-1 298-102 [ EDO QUALITY W3PECTEDI DLA-ARN Final Report for US Defense Logistics Agency on DDFG-T2/P3: 3D...SCAN SYSTEMS INTEGRATION Contract Number SPO100-95-D-1014 Contractor Ohio University Delivery Order # 0001 Delivery Order Title 3D Scan Systems

  19. PLOT3D/AMES, SGI IRIS VERSION (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  20. PLOT3D/AMES, SGI IRIS VERSION (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  1. 3D polymer scaffold arrays.

    PubMed

    Simon, Carl G; Yang, Yanyin; Dorsey, Shauna M; Ramalingam, Murugan; Chatterjee, Kaushik

    2011-01-01

    We have developed a combinatorial platform for fabricating tissue scaffold arrays that can be used for screening cell-material interactions. Traditional research involves preparing samples one at a time for characterization and testing. Combinatorial and high-throughput (CHT) methods lower the cost of research by reducing the amount of time and material required for experiments by combining many samples into miniaturized specimens. In order to help accelerate biomaterials research, many new CHT methods have been developed for screening cell-material interactions where materials are presented to cells as a 2D film or surface. However, biomaterials are frequently used to fabricate 3D scaffolds, cells exist in vivo in a 3D environment and cells cultured in a 3D environment in vitro typically behave more physiologically than those cultured on a 2D surface. Thus, we have developed a platform for fabricating tissue scaffold libraries where biomaterials can be presented to cells in a 3D format.

  2. Autofocus for 3D imaging

    NASA Astrophysics Data System (ADS)

    Lee-Elkin, Forest

    2008-04-01

    Three dimensional (3D) autofocus remains a significant challenge for the development of practical 3D multipass radar imaging. The current 2D radar autofocus methods are not readily extendable across sensor passes. We propose a general framework that allows a class of data adaptive solutions for 3D auto-focus across passes with minimal constraints on the scene contents. The key enabling assumption is that portions of the scene are sparse in elevation which reduces the number of free variables and results in a system that is simultaneously solved for scatterer heights and autofocus parameters. The proposed method extends 2-pass interferometric synthetic aperture radar (IFSAR) methods to an arbitrary number of passes allowing the consideration of scattering from multiple height locations. A specific case from the proposed autofocus framework is solved and demonstrates autofocus and coherent multipass 3D estimation across the 8 passes of the "Gotcha Volumetric SAR Data Set" X-Band radar data.

  3. Combinatorial 3D Mechanical Metamaterials

    NASA Astrophysics Data System (ADS)

    Coulais, Corentin; Teomy, Eial; de Reus, Koen; Shokef, Yair; van Hecke, Martin

    2015-03-01

    We present a class of elastic structures which exhibit 3D-folding motion. Our structures consist of cubic lattices of anisotropic unit cells that can be tiled in a complex combinatorial fashion. We design and 3d-print this complex ordered mechanism, in which we combine elastic hinges and defects to tailor the mechanics of the material. Finally, we use this large design space to encode smart functionalities such as surface patterning and multistability.

  4. 3D-Printing for Analytical Ultracentrifugation

    PubMed Central

    Desai, Abhiksha; Krynitsky, Jonathan; Pohida, Thomas J.; Zhao, Huaying

    2016-01-01

    Analytical ultracentrifugation (AUC) is a classical technique of physical biochemistry providing information on size, shape, and interactions of macromolecules from the analysis of their migration in centrifugal fields while free in solution. A key mechanical element in AUC is the centerpiece, a component of the sample cell assembly that is mounted between the optical windows to allow imaging and to seal the sample solution column against high vacuum while exposed to gravitational forces in excess of 300,000 g. For sedimentation velocity it needs to be precisely sector-shaped to allow unimpeded radial macromolecular migration. During the history of AUC a great variety of centerpiece designs have been developed for different types of experiments. Here, we report that centerpieces can now be readily fabricated by 3D printing at low cost, from a variety of materials, and with customized designs. The new centerpieces can exhibit sufficient mechanical stability to withstand the gravitational forces at the highest rotor speeds and be sufficiently precise for sedimentation equilibrium and sedimentation velocity experiments. Sedimentation velocity experiments with bovine serum albumin as a reference molecule in 3D printed centerpieces with standard double-sector design result in sedimentation boundaries virtually indistinguishable from those in commercial double-sector epoxy centerpieces, with sedimentation coefficients well within the range of published values. The statistical error of the measurement is slightly above that obtained with commercial epoxy, but still below 1%. Facilitated by modern open-source design and fabrication paradigms, we believe 3D printed centerpieces and AUC accessories can spawn a variety of improvements in AUC experimental design, efficiency and resource allocation. PMID:27525659

  5. 3D-Printing for Analytical Ultracentrifugation.

    PubMed

    Desai, Abhiksha; Krynitsky, Jonathan; Pohida, Thomas J; Zhao, Huaying; Schuck, Peter

    2016-01-01

    Analytical ultracentrifugation (AUC) is a classical technique of physical biochemistry providing information on size, shape, and interactions of macromolecules from the analysis of their migration in centrifugal fields while free in solution. A key mechanical element in AUC is the centerpiece, a component of the sample cell assembly that is mounted between the optical windows to allow imaging and to seal the sample solution column against high vacuum while exposed to gravitational forces in excess of 300,000 g. For sedimentation velocity it needs to be precisely sector-shaped to allow unimpeded radial macromolecular migration. During the history of AUC a great variety of centerpiece designs have been developed for different types of experiments. Here, we report that centerpieces can now be readily fabricated by 3D printing at low cost, from a variety of materials, and with customized designs. The new centerpieces can exhibit sufficient mechanical stability to withstand the gravitational forces at the highest rotor speeds and be sufficiently precise for sedimentation equilibrium and sedimentation velocity experiments. Sedimentation velocity experiments with bovine serum albumin as a reference molecule in 3D printed centerpieces with standard double-sector design result in sedimentation boundaries virtually indistinguishable from those in commercial double-sector epoxy centerpieces, with sedimentation coefficients well within the range of published values. The statistical error of the measurement is slightly above that obtained with commercial epoxy, but still below 1%. Facilitated by modern open-source design and fabrication paradigms, we believe 3D printed centerpieces and AUC accessories can spawn a variety of improvements in AUC experimental design, efficiency and resource allocation.

  6. The 3D rocket combustor acoustics model

    NASA Technical Reports Server (NTRS)

    Priem, Richard J.; Breisacher, Kevin J.

    1992-01-01

    The theory and procedures for determining the characteristics of pressure oscillations in rocket engines with prescribed burning rate oscillations are presented. Analyses including radial and hub baffles and absorbers can be performed in one, two, and three dimensions. Pressure and velocity oscillations calculated using this procedure are presented for the SSME to show the influence of baffles and absorbers on the burning rate oscillations required to achieve neutral stability. Comparisons are made between the results obtained utilizing 1-D, 2-D, and 3-D assumptions with regards to capturing the physical phenomena of interest and computational requirements.

  7. Three-dimensional seismic velocity model of the West Bohemia/Vogtland seismoactive region

    NASA Astrophysics Data System (ADS)

    Růžek, Bohuslav; Horálek, Josef

    2013-11-01

    In this paper, we present a smooth 3-D seismic model WB2012 for the West Bohemia/Vogtland earthquake swarm region derived by means of seismic tomography. Inverted data were represented by a set of 2920 P-wave traveltimes from controlled shots fired in a framework of different experiments and a set of 11339 P- and S-wave arrival times from 661 local earthquakes between 1991 December and 2010 March. We used a standard tomographic approach for independent calculation of P- and S-wave velocity fields in a rectangular grid whose size was 1 km in all coordinates. The traveltimes and rays were calculated by a numerical solution of the eiconal equation. While locating seismic events, our new WB2012 model yielded arrival time residuals on average by 13 per cent lower and hypocentre depths by 0.95 km shallower compared to the locations of the foci in the standard 1-D vertically inhomogeneous isotropic velocity model of the West Bohemia swarm region WB2005. Further, we converted the P- and S-wave velocities to the bulk modulus K and Poisson's ratio ν. The bulk modulus (˜40-70 GPa) correlates acceptably with the tectonic and geological structure of the area. The anomalously low values of the Poisson's ratio (˜0.15) are typical for the most active focal zones of Nový Kostel and Lazy in West Bohemia.

  8. Modeling of local 3D effects of the April 6th 2009 l’Aquila (Italy) event in the City of Rome

    NASA Astrophysics Data System (ADS)

    Caserta, A.; Oprsal, I.; Rovelli, A.; Marra, F.; Govoni, A.; Vinci, S.

    2009-12-01

    Several events of the seismic sequence started on 6th of April 2009, that struck the town of l'Aquila, Italy, have been recorded by an array of seismic stations, located approximately 90 km south-west of the epicenters. One of the stations is in a 80-m-deep borehole, installed since the early 2008 in the middle of the main sedimentary body of the city: the Tiber valley. This represents a unique opportunity to tune seismic simulations of the soil shaking due to a seismic sequence located in Central Apennines region. This latter is considered, with the Albani Hills one, the main seismogenic area responsible of the seismic hazard in the city. We have generated a 3D velocity model for a portion of the city (5 EW x 3 NS km2 wide, and 200 m deep, including topography) where the array is located. A viscoelastic wave propagation due to S-wave pulse of general polarization and given incidence is obtained by the 3D FD hybrid numerical modeling. The 3D pulse response and the borehole recording are then used to generate the complete 3D synthetics covering the area. The results are verified by comparing to the surface recordings and large ground motion amplifications data.

  9. From 3D view to 3D print

    NASA Astrophysics Data System (ADS)

    Dima, M.; Farisato, G.; Bergomi, M.; Viotto, V.; Magrin, D.; Greggio, D.; Farinato, J.; Marafatto, L.; Ragazzoni, R.; Piazza, D.

    2014-08-01

    In the last few years 3D printing is getting more and more popular and used in many fields going from manufacturing to industrial design, architecture, medical support and aerospace. 3D printing is an evolution of bi-dimensional printing, which allows to obtain a solid object from a 3D model, realized with a 3D modelling software. The final product is obtained using an additive process, in which successive layers of material are laid down one over the other. A 3D printer allows to realize, in a simple way, very complex shapes, which would be quite difficult to be produced with dedicated conventional facilities. Thanks to the fact that the 3D printing is obtained superposing one layer to the others, it doesn't need any particular work flow and it is sufficient to simply draw the model and send it to print. Many different kinds of 3D printers exist based on the technology and material used for layer deposition. A common material used by the toner is ABS plastics, which is a light and rigid thermoplastic polymer, whose peculiar mechanical properties make it diffusely used in several fields, like pipes production and cars interiors manufacturing. I used this technology to create a 1:1 scale model of the telescope which is the hardware core of the space small mission CHEOPS (CHaracterising ExOPlanets Satellite) by ESA, which aims to characterize EXOplanets via transits observations. The telescope has a Ritchey-Chrétien configuration with a 30cm aperture and the launch is foreseen in 2017. In this paper, I present the different phases for the realization of such a model, focusing onto pros and cons of this kind of technology. For example, because of the finite printable volume (10×10×12 inches in the x, y and z directions respectively), it has been necessary to split the largest parts of the instrument in smaller components to be then reassembled and post-processed. A further issue is the resolution of the printed material, which is expressed in terms of layers

  10. YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters

    NASA Astrophysics Data System (ADS)

    Schild, Jonas; Seele, Sven; Masuch, Maic

    2012-03-01

    Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.

  11. Speaking Volumes About 3-D

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In 1999, Genex submitted a proposal to Stennis Space Center for a volumetric 3-D display technique that would provide multiple users with a 360-degree perspective to simultaneously view and analyze 3-D data. The futuristic capabilities of the VolumeViewer(R) have offered tremendous benefits to commercial users in the fields of medicine and surgery, air traffic control, pilot training and education, computer-aided design/computer-aided manufacturing, and military/battlefield management. The technology has also helped NASA to better analyze and assess the various data collected by its satellite and spacecraft sensors. Genex capitalized on its success with Stennis by introducing two separate products to the commercial market that incorporate key elements of the 3-D display technology designed under an SBIR contract. The company Rainbow 3D(R) imaging camera is a novel, three-dimensional surface profile measurement system that can obtain a full-frame 3-D image in less than 1 second. The third product is the 360-degree OmniEye(R) video system. Ideal for intrusion detection, surveillance, and situation management, this unique camera system offers a continuous, panoramic view of a scene in real time.

  12. High-resolution imaging of crustal melts using 3D full-waveform seismic inversion

    NASA Astrophysics Data System (ADS)

    Warner, M.; Morgan, J. V.

    2013-12-01

    A newly practical seismic imaging technique, 3D full-waveform inversion (FWI), now has the ability to image zones of melt and melt pathways throughout the crust with a better resolution than any other geophysical method. 3D FWI has recently changed practice within the petroleum industry where it is used to obtain high-resolution high-fidelity models of physical properties in the sub-surface that are both interpreted directly and used to improve the migration of deeper reflections. This technology has been spectacularly successful in improving the imaging of reservoirs beneath shallow heterogeneities produced by, for example, gas clouds, buried fluvial channels, carbonate reefs and salt bodies. During FWI, the sub-surface model is recovered principally by using the low-frequency transmitted, refracted portion of the wavefield which is most sensitive to the macro-velocity structure. In the petroleum industry, these inversions are now routinely performed using long-offset surface-streamer and ocean-bottom data to maximum source-receiver offsets of about 15 km, leading to a maximum penetration depth of around 5 km. Using longer offsets, it is possible to extend this technology to image deeper crustal targets. Localised zones of partial melt produce large changes in p-wave and s-wave properties that are restricted in their spatial extent, and that therefore form ideal targets for 3D FWI. We have performed a suite of tests to explore the use of 3D FWI in imaging melt distribution beneath the active volcano of Montserrat. We built a model of the subsurface using a 3D travel-time tomographic model obtained from the SEA CALIPSO experiment. We added two magma chambers in accordance with a model obtained using surface-elevation changes and geochemical data. We used a wide-angle, wide-azimuth acquisition geometry to generate a fully-elastic synthetic seismic dataset, added noise, and inverted the windowed transmitted arrivals only. We used an elastic code for the forward

  13. Distinct S wave reflector in the midcrust beneath Nikko-Shirane volcano in the northeastern Japan arc

    NASA Astrophysics Data System (ADS)

    Matsumoto, Satoshi; Hasegawa, Akira

    1996-02-01

    Distinct S waves reflected from a midcrustal seismic velocity discontinuity are detected beneath Nikko-Shirane volcano in the southernmost part of the northeastern Japan arc. A detailed travel time analysis of the reflected S waves by using data acquired through a dense seismic network temporarily set up in this region shows that this unusual S wave reflector is distributed over an area of 15 × 15 km2 at depths ranging from 8 to 15 km. The reflector has a conical shape becoming shallow toward the summit of Nikko-Shirane volcano. Observed amplitude spectral ratios of reflected S waves to direct S waves show that the reflector body has a strong velocity contrast to the surrounding medium and its thickness is of the order of 100 m at most. The reflector body is approximated by two thin layers probably filled with partially molten materials. Cutoff depth for shallow seismicity in this area is 3-5 km above the reflector and becomes shallow toward Nikko-Shirane volcano, nearly parallel to the reflector. The depth to brittle-ductile transition zone seems to be prescribed by the existence of the reflector body, which is perhaps a thin magma body.

  14. Macrophage podosomes go 3D.

    PubMed

    Van Goethem, Emeline; Guiet, Romain; Balor, Stéphanie; Charrière, Guillaume M; Poincloux, Renaud; Labrousse, Arnaud; Maridonneau-Parini, Isabelle; Le Cabec, Véronique

    2011-01-01

    Macrophage tissue infiltration is a critical step in the immune response against microorganisms and is also associated with disease progression in chronic inflammation and cancer. Macrophages are constitutively equipped with specialized structures called podosomes dedicated to extracellular matrix (ECM) degradation. We recently reported that these structures play a critical role in trans-matrix mesenchymal migration mode, a protease-dependent mechanism. Podosome molecular components and their ECM-degrading activity have been extensively studied in two dimensions (2D), but yet very little is known about their fate in three-dimensional (3D) environments. Therefore, localization of podosome markers and proteolytic activity were carefully examined in human macrophages performing mesenchymal migration. Using our gelled collagen I 3D matrix model to obligate human macrophages to perform mesenchymal migration, classical podosome markers including talin, paxillin, vinculin, gelsolin, cortactin were found to accumulate at the tip of F-actin-rich cell protrusions together with β1 integrin and CD44 but not β2 integrin. Macrophage proteolytic activity was observed at podosome-like protrusion sites using confocal fluorescence microscopy and electron microscopy. The formation of migration tunnels by macrophages inside the matrix was accomplished by degradation, engulfment and mechanic compaction of the matrix. In addition, videomicroscopy revealed that 3D F-actin-rich protrusions of migrating macrophages were as dynamic as their 2D counterparts. Overall, the specifications of 3D podosomes resembled those of 2D podosome rosettes rather than those of individual podosomes. This observation was further supported by the aspect of 3D podosomes in fibroblasts expressing Hck, a master regulator of podosome rosettes in macrophages. In conclusion, human macrophage podosomes go 3D and take the shape of spherical podosome rosettes when the cells perform mesenchymal migration. This work

  15. 3D Printed Bionic Nanodevices.

    PubMed

    Kong, Yong Lin; Gupta, Maneesh K; Johnson, Blake N; McAlpine, Michael C

    2016-06-01

    The ability to three-dimensionally interweave biological and functional materials could enable the creation of bionic devices possessing unique and compelling geometries, properties, and functionalities. Indeed, interfacing high performance active devices with biology could impact a variety of fields, including regenerative bioelectronic medicines, smart prosthetics, medical robotics, and human-machine interfaces. Biology, from the molecular scale of DNA and proteins, to the macroscopic scale of tissues and organs, is three-dimensional, often soft and stretchable, and temperature sensitive. This renders most biological platforms incompatible with the fabrication and materials processing methods that have been developed and optimized for functional electronics, which are typically planar, rigid and brittle. A number of strategies have been developed to overcome these dichotomies. One particularly novel approach is the use of extrusion-based multi-material 3D printing, which is an additive manufacturing technology that offers a freeform fabrication strategy. This approach addresses the dichotomies presented above by (1) using 3D printing and imaging for customized, hierarchical, and interwoven device architectures; (2) employing nanotechnology as an enabling route for introducing high performance materials, with the potential for exhibiting properties not found in the bulk; and (3) 3D printing a range of soft and nanoscale materials to enable the integration of a diverse palette of high quality functional nanomaterials with biology. Further, 3D printing is a multi-scale platform, allowing for the incorporation of functional nanoscale inks, the printing of microscale features, and ultimately the creation of macroscale devices. This blending of 3D printing, novel nanomaterial properties, and 'living' platforms may enable next-generation bionic systems. In this review, we highlight this synergistic integration of the unique properties of nanomaterials with the

  16. Petal, terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at the lower area of this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. The metallic object at lower right is part of the lander's low-gain antenna. This image is part of a 3D 'monster

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  17. 3D Computations and Experiments

    SciTech Connect

    Couch, R; Faux, D; Goto, D; Nikkel, D

    2004-04-05

    This project consists of two activities. Task A, Simulations and Measurements, combines all the material model development and associated numerical work with the materials-oriented experimental activities. The goal of this effort is to provide an improved understanding of dynamic material properties and to provide accurate numerical representations of those properties for use in analysis codes. Task B, ALE3D Development, involves general development activities in the ALE3D code with the focus of improving simulation capabilities for problems of mutual interest to DoD and DOE. Emphasis is on problems involving multi-phase flow, blast loading of structures and system safety/vulnerability studies.

  18. 3D Finite-Difference Modeling of Scattered Teleseismic Wavefields in a Subduction Zone

    NASA Astrophysics Data System (ADS)

    Morozov, I. B.; Zheng, H.

    2005-12-01

    For a teleseismic array targeting subducting crust in a zone of active subduction, scattering from the zone underlying the trench result in subhorizontally-propagating waves that could be difficult to distinguish from converted P- and S- wave backscattered from the surface. Because back-scattered modes often provide the most spectacular images of subducting slabs, it is important to understand their differences from the arrivals scattered from the trench zone. To investigate the detailed teleseismic wavefield in a subduction zone environment, we performed a full-waveform, 3-D visco-elastic finite-difference modeling of teleseismic wave propagation using a Beowulf cluster. The synthetics show strong scattering from the trench zone, dominated by the mantle and crustal P-waves propagating at 6.2-8.1.km/s and slower. These scattered waves occupy the same time and moveout intervals as the backscattered modes, and also have similar amplitudes. Although their amplitude decay characters are different, with the uncertainties in the velocity and density structure of the subduction zone, unambiguous distinguishing of these modes appears difficult. However, under minimal assumptions (in particular, without invoking slab dehydration), recent observations of receiver function amplitudes decreasing away from the trench favor the interpretation of trench-zone scattering.

  19. The World of 3-D.

    ERIC Educational Resources Information Center

    Mayshark, Robin K.

    1991-01-01

    Students explore three-dimensional properties by creating red and green wall decorations related to Christmas. Students examine why images seem to vibrate when red and green pieces are small and close together. Instructions to conduct the activity and construct 3-D glasses are given. (MDH)

  20. 3D Printing: Exploring Capabilities

    ERIC Educational Resources Information Center

    Samuels, Kyle; Flowers, Jim

    2015-01-01

    As 3D printers become more affordable, schools are using them in increasing numbers. They fit well with the emphasis on product design in technology and engineering education, allowing students to create high-fidelity physical models to see and test different iterations in their product designs. They may also help students to "think in three…

  1. SNL3dFace

    SciTech Connect

    Russ, Trina; Koch, Mark; Koudelka, Melissa; Peters, Ralph; Little, Charles; Boehnen, Chris; Peters, Tanya

    2007-07-20

    This software distribution contains MATLAB and C++ code to enable identity verification using 3D images that may or may not contain a texture component. The code is organized to support system performance testing and system capability demonstration through the proper configuration of the available user interface. Using specific algorithm parameters the face recognition system has been demonstrated to achieve a 96.6% verification rate (Pd) at 0.001 false alarm rate. The system computes robust facial features of a 3D normalized face using Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (FLDA). A 3D normalized face is obtained by alighning each face, represented by a set of XYZ coordinated, to a scaled reference face using the Iterative Closest Point (ICP) algorithm. The scaled reference face is then deformed to the input face using an iterative framework with parameters that control the deformed surface regulation an rate of deformation. A variety of options are available to control the information that is encoded by the PCA. Such options include the XYZ coordinates, the difference of each XYZ coordinates from the reference, the Z coordinate, the intensity/texture values, etc. In addition to PCA/FLDA feature projection this software supports feature matching to obtain similarity matrices for performance analysis. In addition, this software supports visualization of the STL, MRD, 2D normalized, and PCA synthetic representations in a 3D environment.

  2. Making Inexpensive 3-D Models

    ERIC Educational Resources Information Center

    Manos, Harry

    2016-01-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…

  3. TACO3D. 3-D Finite Element Heat Transfer Code

    SciTech Connect

    Mason, W.E.

    1992-03-04

    TACO3D is a three-dimensional, finite-element program for heat transfer analysis. An extension of the two-dimensional TACO program, it can perform linear and nonlinear analyses and can be used to solve either transient or steady-state problems. The program accepts time-dependent or temperature-dependent material properties, and materials may be isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions and loadings are available including temperature, flux, convection, and radiation boundary conditions and internal heat generation. Additional specialized features treat enclosure radiation, bulk nodes, and master/slave internal surface conditions (e.g., contact resistance). Data input via a free-field format is provided. A user subprogram feature allows for any type of functional representation of any independent variable. A profile (bandwidth) minimization option is available. The code is limited to implicit time integration for transient solutions. TACO3D has no general mesh generation capability. Rows of evenly-spaced nodes and rows of sequential elements may be generated, but the program relies on separate mesh generators for complex zoning. TACO3D does not have the ability to calculate view factors internally. Graphical representation of data in the form of time history and spatial plots is provided through links to the POSTACO and GRAPE postprocessor codes.

  4. Forensic 3D scene reconstruction

    NASA Astrophysics Data System (ADS)

    Little, Charles Q.; Small, Daniel E.; Peters, Ralph R.; Rigdon, J. B.

    2000-05-01

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a fieldable prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  5. 3D Printed Robotic Hand

    NASA Technical Reports Server (NTRS)

    Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.

    2013-01-01

    Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was $167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.

  6. Comparing swimsuits in 3D.

    PubMed

    van Geer, Erik; Molenbroek, Johan; Schreven, Sander; deVoogd-Claessen, Lenneke; Toussaint, Huib

    2012-01-01

    In competitive swimming, suits have become more important. These suits influence friction, pressure and wave drag. Friction drag is related to the surface properties whereas both pressure and wave drag are greatly influenced by body shape. To find a relationship between the body shape and the drag, the anthropometry of several world class female swimmers wearing different suits was accurately defined using a 3D scanner and traditional measuring methods. The 3D scans delivered more detailed information about the body shape. On the same day the swimmers did performance tests in the water with the tested suits. Afterwards the result of the performance tests and the differences found in body shape was analyzed to determine the deformation caused by a swimsuit and its effect on the swimming performance. Although the amount of data is limited because of the few test subjects, there is an indication that the deformation of the body influences the swimming performance.

  7. Forensic 3D Scene Reconstruction

    SciTech Connect

    LITTLE,CHARLES Q.; PETERS,RALPH R.; RIGDON,J. BRIAN; SMALL,DANIEL E.

    1999-10-12

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  8. 3D-graphite structure

    SciTech Connect

    Belenkov, E. A. Ali-Pasha, V. A.

    2011-01-15

    The structure of clusters of some new carbon 3D-graphite phases have been calculated using the molecular-mechanics methods. It is established that 3D-graphite polytypes {alpha}{sub 1,1}, {alpha}{sub 1,3}, {alpha}{sub 1,5}, {alpha}{sub 2,1}, {alpha}{sub 2,3}, {alpha}{sub 3,1}, {beta}{sub 1,2}, {beta}{sub 1,4}, {beta}{sub 1,6}, {beta}{sub 2,1}, and {beta}{sub 3,2} consist of sp{sup 2}-hybridized atoms, have hexagonal unit cells, and differ in regards to the structure of layers and order of their alternation. A possible way to experimentally synthesize new carbon phases is proposed: the polymerization and carbonization of hydrocarbon molecules.

  9. [Real time 3D echocardiography

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  10. Lattice Boltzmann Method for 3-D Flows with Curved Boundary

    NASA Technical Reports Server (NTRS)

    Mei, Renwei; Shyy, Wei; Yu, Dazhi; Luo, Li-Shi

    2002-01-01

    In this work, we investigate two issues that are important to computational efficiency and reliability in fluid dynamics applications of the lattice, Boltzmann equation (LBE): (1) Computational stability and accuracy of different lattice Boltzmann models and (2) the treatment of the boundary conditions on curved solid boundaries and their 3-D implementations. Three athermal 3-D LBE models (D3QI5, D3Ql9, and D3Q27) are studied and compared in terms of efficiency, accuracy, and robustness. The boundary treatment recently developed by Filippova and Hanel and Met et al. in 2-D is extended to and implemented for 3-D. The convergence, stability, and computational efficiency of the 3-D LBE models with the boundary treatment for curved boundaries were tested in simulations of four 3-D flows: (1) Fully developed flows in a square duct, (2) flow in a 3-D lid-driven cavity, (3) fully developed flows in a circular pipe, and (4) a uniform flow over a sphere. We found that while the fifteen-velocity 3-D (D3Ql5) model is more prone to numerical instability and the D3Q27 is more computationally intensive, the 63Q19 model provides a balance between computational reliability and efficiency. Through numerical simulations, we demonstrated that the boundary treatment for 3-D arbitrary curved geometry has second-order accuracy and possesses satisfactory stability characteristics.

  11. GPU-Accelerated Denoising in 3D (GD3D)

    SciTech Connect

    2013-10-01

    The raw computational power GPU Accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. This software addresses two facets of this promising application: what tuning is necessary to achieve optimal performance on a modern GPU? And what parameters yield the best denoising results in practice? To answer the first question, the software performs an autotuning step to empirically determine optimal memory blocking on the GPU. To answer the second, it performs a sweep of algorithm parameters to determine the combination that best reduces the mean squared error relative to a noiseless reference image.

  12. Fault zone characterization using P- and S-waves

    NASA Astrophysics Data System (ADS)

    Wawerzinek, Britta; Buness, Hermann; Polom, Ulrich; Tanner, David C.; Thomas, Rüdiger

    2014-05-01

    Although deep fault zones have high potential for geothermal energy extraction, their real usability depends on complex lithological and tectonic factors. Therefore a detailed fault zone exploration using P- and S-wave reflection seismic data is required. P- and S-wave reflection seismic surveys were carried out along and across the eastern border of the Leinetal Graben in Lower Saxony, Germany, to analyse the structural setting, different reflection characteristics and possible anisotropic effects. In both directions the P-wave reflection seismic measurements show a detailed and complex structure. This structure was developed during several tectonic phases and comprises both steeply- and shallowly-dipping faults. In a profile perpendicular to the graben, a strong P-wave reflector is interpreted as shallowly west-dipping fault that is traceable from the surface down to 500 m depth. It is also detectable along the graben. In contrast, the S-waves show different reflection characteristics: There is no indication of the strong P-wave reflector in the S-wave reflection seismic measurements - neither across nor along the graben. Only diffuse S-wave reflections are observable in this region. Due to the higher resolution of S-waves in the near-surface area it is possible to map structures which cannot be detected in P-wave reflection seismic, e.g the thinning of the uppermost Jurassic layer towards the south. In the next step a petrophysical analysis will be conducted by using seismic FD modelling to a) determine the cause (lithological, structural, or a combination of both) of the different reflection characteristics of P- and S-waves, b) characterize the fault zone, as well as c) analyse the influence of different fault zone properties on the seismic wave field. This work is part of the gebo collaborative research programme which is funded by the 'Niedersächsisches Ministerium für Wissenschaft und Kultur' and Baker Hughes.

  13. Applications of Doppler Tomography in 2D and 3D

    NASA Astrophysics Data System (ADS)

    Richards, M.; Budaj, J.; Agafonov, M.; Sharova, O.

    2010-12-01

    Over the past few years, the applications of Doppler tomography have been extended beyond the usual calculation of 2D velocity images of circumstellar gas flows. This technique has now been used with the new Shellspec spectrum synthesis code to demonstrate the effective modeling of the accretion disk and gas stream in the TT Hya Algol binary. The 2D tomography procedure projects all sources of emission onto a single central (Vx, Vy) velocity plane even though the gas is expected to flow beyond that plane. So, new 3D velocity images were derived with the Radioastronomical Approach method by assuming a grid of Vz values transverse to the central 2D plane. The 3D approach has been applied to the U CrB and RS Vul Algol-type binaries to reveal substantial flow structures beyond the central velocity plane.

  14. Magmatic Systems in 3-D

    NASA Astrophysics Data System (ADS)

    Kent, G. M.; Harding, A. J.; Babcock, J. M.; Orcutt, J. A.; Bazin, S.; Singh, S.; Detrick, R. S.; Canales, J. P.; Carbotte, S. M.; Diebold, J.

    2002-12-01

    Multichannel seismic (MCS) images of crustal magma chambers are ideal targets for advanced visualization techniques. In the mid-ocean ridge environment, reflections originating at the melt-lens are well separated from other reflection boundaries, such as the seafloor, layer 2A and Moho, which enables the effective use of transparency filters. 3-D visualization of seismic reflectivity falls into two broad categories: volume and surface rendering. Volumetric-based visualization is an extremely powerful approach for the rapid exploration of very dense 3-D datasets. These 3-D datasets are divided into volume elements or voxels, which are individually color coded depending on the assigned datum value; the user can define an opacity filter to reject plotting certain voxels. This transparency allows the user to peer into the data volume, enabling an easy identification of patterns or relationships that might have geologic merit. Multiple image volumes can be co-registered to look at correlations between two different data types (e.g., amplitude variation with offsets studies), in a manner analogous to draping attributes onto a surface. In contrast, surface visualization of seismic reflectivity usually involves producing "fence" diagrams of 2-D seismic profiles that are complemented with seafloor topography, along with point class data, draped lines and vectors (e.g. fault scarps, earthquake locations and plate-motions). The overlying seafloor can be made partially transparent or see-through, enabling 3-D correlations between seafloor structure and seismic reflectivity. Exploration of 3-D datasets requires additional thought when constructing and manipulating these complex objects. As numbers of visual objects grow in a particular scene, there is a tendency to mask overlapping objects; this clutter can be managed through the effective use of total or partial transparency (i.e., alpha-channel). In this way, the co-variation between different datasets can be investigated

  15. Dynamics of 3D isolated thermal filaments

    NASA Astrophysics Data System (ADS)

    Walkden, N. R.; Easy, L.; Militello, F.; Omotani, J. T.

    2016-11-01

    Simulations have been carried out to establish how electron thermal physics, introduced in the form of a dynamic electron temperature, affects isolated filament motion and dynamics in 3D. It is found that thermal effects impact filament motion in two major ways when the pressure perturbation within the filament is supported primarily through a temperature increase as opposed to density: they lead to a strong increase in filament propagation in the bi-normal direction and a significant decrease in net radial propagation. Both effects arise from the temperature dependence of the sheath current which leads to a non-uniform floating potential, with the latter effect supplemented by faster pressure loss. The reduction in radial velocity can only occur when the filament cross-section loses angular symmetry. The behaviour is observed across different filament sizes and suggests that filaments with much larger temperature perturbations than density perturbations are more strongly confined to the near SOL region.

  16. Ensemble 3D PTV for high resolution turbulent statistics

    NASA Astrophysics Data System (ADS)

    Agüera, Nereida; Cafiero, Gioacchino; Astarita, Tommaso; Discetti, Stefano

    2016-12-01

    A method to extract turbulent statistics from three-dimensional (3D) PIV measurements via ensemble averaging is presented. The proposed technique is a 3D extension of the ensemble particle tracking velocimetry methods, which consist in summing distributions of velocity vectors calculated on low image density samples and then extract the statistical moments from the velocity vectors within sub-volumes, with the size of the sub-volume depending on the desired number of particles and on the available number of snapshots. The extension to 3D measurements poses the additional difficulty of sparse velocity vectors distributions, thus requiring a large number of snapshots to achieve high resolution measurements with a sufficient degree of accuracy. At the current state, this hinders the achievement of single-voxel measurements, unless millions of samples are available. Consequently, one has to give up spatial resolution and live with still relatively large (if compared to the voxel) sub-volumes. This leads to the further problem of the possible occurrence of a residual mean velocity gradient within the sub-volumes, which significantly contaminates the computation of second order moments. In this work, we propose a method to reduce the residual gradient effect, allowing to reach high resolution even with relatively large interrogation spots, therefore still retrieving a large number of particles on which it is possible to calculate turbulent statistics. The method consists in applying a polynomial fit to the velocity distributions within each sub-volume trying to mimic the residual mean velocity gradient.

  17. Interactive 3D Mars Visualization

    NASA Technical Reports Server (NTRS)

    Powell, Mark W.

    2012-01-01

    The Interactive 3D Mars Visualization system provides high-performance, immersive visualization of satellite and surface vehicle imagery of Mars. The software can be used in mission operations to provide the most accurate position information for the Mars rovers to date. When integrated into the mission data pipeline, this system allows mission planners to view the location of the rover on Mars to 0.01-meter accuracy with respect to satellite imagery, with dynamic updates to incorporate the latest position information. Given this information so early in the planning process, rover drivers are able to plan more accurate drive activities for the rover than ever before, increasing the execution of science activities significantly. Scientifically, this 3D mapping information puts all of the science analyses to date into geologic context on a daily basis instead of weeks or months, as was the norm prior to this contribution. This allows the science planners to judge the efficacy of their previously executed science observations much more efficiently, and achieve greater science return as a result. The Interactive 3D Mars surface view is a Mars terrain browsing software interface that encompasses the entire region of exploration for a Mars surface exploration mission. The view is interactive, allowing the user to pan in any direction by clicking and dragging, or to zoom in or out by scrolling the mouse or touchpad. This set currently includes tools for selecting a point of interest, and a ruler tool for displaying the distance between and positions of two points of interest. The mapping information can be harvested and shared through ubiquitous online mapping tools like Google Mars, NASA WorldWind, and Worldwide Telescope.

  18. Characteristic wavefield in an experimental rock sample inferred from a 3D FDM simulation

    NASA Astrophysics Data System (ADS)

    Yoshimitsu, N.; Furumura, T.; Maeda, T.

    2014-12-01

    We investigate the origin of wave packets in elastic waves propagate through a rock sample based on a 3D finite difference method (FDM) simulation. Though direct waves of the transmitted waves have been applied to estimate the internal structure of a rock sample, later part of the waveforms did not utilized because their origin were unclear. Understanding the reflection and conversion effect in a rock sample would help to retrieve more information from whole waveform as with the analysis in natural fields. We numerically simulated the elastic wave propagation in a medium model which covers a cylindrical shape of a rock sample. The model was discretized into 1024 x 1024 x 2048 grid points with an interval of 54 micrometer in horizontal direction and 60 micrometer in vertical direction. The density, P wave velocity, and S wave velocity of the each grid point are assumed to be proportional to the X-ray absorption coefficient derived from the micro focus X-ray CT images of a Westery granite sample. We applied a single point force on the boundary of the model sample which mimics realistic transducer movement. The wave propagation movie obtained from the numerical simulation shows very complicated wavefield in a rock sample. Because a rock sample is small and closed, once waves are radiated, they were trapped in the sample by repeating reflection and conversion. Many reflected waves which followed by the converted waves were generated at the sample side surface as well as the upper and lower end. The phase with the largest amplitude propagate along the curved boundary was detected as Rayleigh wave from the particle motions on the sample side surface. Additionally, the surface waves were observed not only in the horizontal section but also in the vertical section. Our simulation indicated that the later phases of the transmitted waves are highly affected by the sample boundary. In order to extract accurate interior information from the transmitted waves, elimination

  19. 3D Nanostructuring of Semiconductors

    NASA Astrophysics Data System (ADS)

    Blick, Robert

    2000-03-01

    Modern semiconductor technology allows to machine devices on the nanometer scale. I will discuss the current limits of the fabrication processes, which enable the definition of single electron transistors with dimensions down to 8 nm. In addition to the conventional 2D patterning and structuring of semiconductors, I will demonstrate how to apply 3D nanostructuring techniques to build freely suspended single-crystal beams with lateral dimension down to 20 nm. In transport measurements in the temperature range from 30 mK up to 100 K these nano-crystals are characterized regarding their electronic as well as their mechanical properties. Moreover, I will present possible applications of these devices.

  20. What Lies Ahead (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D cylindrical-perspective mosaic taken by the navigation camera on the Mars Exploration Rover Spirit on sol 82 shows the view south of the large crater dubbed 'Bonneville.' The rover will travel toward the Columbia Hills, seen here at the upper left. The rock dubbed 'Mazatzal' and the hole the rover drilled in to it can be seen at the lower left. The rover's position is referred to as 'Site 22, Position 32.' This image was geometrically corrected to make the horizon appear flat.

  1. Making Inexpensive 3-D Models

    NASA Astrophysics Data System (ADS)

    Manos, Harry

    2016-03-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the TPT theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity well tailored to specific class lessons. Most of the supplies are readily available in the home or at school: rubbing alcohol, a rag, two colors of spray paint, art brushes, and masking tape. The cost of these supplies, if you don't have them, is less than 20.

  2. A Clean Adirondack (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This is a 3-D anaglyph showing a microscopic image taken of an area measuring 3 centimeters (1.2 inches) across on the rock called Adirondack. The image was taken at Gusev Crater on the 33rd day of the Mars Exploration Rover Spirit's journey (Feb. 5, 2004), after the rover used its rock abrasion tool brush to clean the surface of the rock. Dust, which was pushed off to the side during cleaning, can still be seen to the left and in low areas of the rock.

  3. 3D Printed Shelby Cobra

    SciTech Connect

    Love, Lonnie

    2015-01-09

    ORNL's newly printed 3D Shelby Cobra was showcased at the 2015 NAIAS in Detroit. This "laboratory on wheels" uses the Shelby Cobra design, celebrating the 50th anniversary of this model and honoring the first vehicle to be voted a national monument. The Shelby was printed at the Department of Energy’s Manufacturing Demonstration Facility at ORNL using the BAAM (Big Area Additive Manufacturing) machine and is intended as a “plug-n-play” laboratory on wheels. The Shelby will allow research and development of integrated components to be tested and enhanced in real time, improving the use of sustainable, digital manufacturing solutions in the automotive industry.

  4. Positional Awareness Map 3D (PAM3D)

    NASA Technical Reports Server (NTRS)

    Hoffman, Monica; Allen, Earl L.; Yount, John W.; Norcross, April Louise

    2012-01-01

    The Western Aeronautical Test Range of the National Aeronautics and Space Administration s Dryden Flight Research Center needed to address the aging software and hardware of its current situational awareness display application, the Global Real-Time Interactive Map (GRIM). GRIM was initially developed in the late 1980s and executes on older PC architectures using a Linux operating system that is no longer supported. Additionally, the software is difficult to maintain due to its complexity and loss of developer knowledge. It was decided that a replacement application must be developed or acquired in the near future. The replacement must provide the functionality of the original system, the ability to monitor test flight vehicles in real-time, and add improvements such as high resolution imagery and true 3-dimensional capability. This paper will discuss the process of determining the best approach to replace GRIM, and the functionality and capabilities of the first release of the Positional Awareness Map 3D.

  5. The 3D crustal structure of Northeastern Tibetan area from seismic tomography

    NASA Astrophysics Data System (ADS)

    Sun, Anhui

    2015-04-01

    The Northeastern Tibetan region is located in the border area of three sub-plates in China, i.e. the Tibetan plateau, North China block and Xinjiang block. Effected simultaneously by the extrusion driven by the India-Eurasia plat collision and the blockage of the Ordos basin, this area has complex geology, strong tectonics activities and suffered from several large historic earthquakes, such as the Haiyuan earthquake (M8.6) in 1920, the Gulang earthquake (M8.0) in 1927. To enhance our understanding of the crustal structure and the interaction between different tectonic blocks of this region, we conduct a three-dimensional (3D) tomographic study by using the arrival time date recorded by regional seismic network. We used 101101 P and 103313 S wave arrival times from 11650 local earthquakes during 1970 to 2013 recorded by 154 permanent seismic stations of the local Seismic Network, installed over five provinces in China, i.e. Gansu, Ningxia, Qinghai, Shanxi, Neimenggu. We first established a 1D primary crustal model from LITHO1.0, an updated crust and lithospheric model of the Earth by weighted averaging. To better performer ray tracing, our inversion involved three discontinuities (including the Moho) with depth variation over the mantle derived from LITHO1.0. Detailed three-dimensional seismic velocity (Vp and Vs) structures of the crust of the Northeastern Tibetan are determined with a horizontal resolution of about 35 km and a depth resolution of 6-20 km. The Poisson's ratio (σ) structure was also estimated after obtained Vp and Vs structures. We detected low-velocity anomalies in the lower crust and relative high-velocity anomalies in the upper crust beneath the Longmenshan faults zone, which are in good agreement with the results of most previous geophysical studies. Our results revealed clear different velocity variation beneath both sides of different tectonic blocks. In addition, we found the correlation between our tomographic result and previous

  6. 3D printed bionic ears.

    PubMed

    Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

    2013-06-12

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.

  7. 3D Printable Graphene Composite

    PubMed Central

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-01-01

    In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C−1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process. PMID:26153673

  8. 3D Printed Bionic Ears

    PubMed Central

    Mannoor, Manu S.; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A.; Soboyejo, Winston O.; Verma, Naveen; Gracias, David H.; McAlpine, Michael C.

    2013-01-01

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the precise anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

  9. Martian terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at lower left in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  10. Martian terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at the lower area of this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  11. 3D structured illumination microscopy

    NASA Astrophysics Data System (ADS)

    Dougherty, William M.; Goodwin, Paul C.

    2011-03-01

    Three-dimensional structured illumination microscopy achieves double the lateral and axial resolution of wide-field microscopy, using conventional fluorescent dyes, proteins and sample preparation techniques. A three-dimensional interference-fringe pattern excites the fluorescence, filling in the "missing cone" of the wide field optical transfer function, thereby enabling axial (z) discrimination. The pattern acts as a spatial carrier frequency that mixes with the higher spatial frequency components of the image, which usually succumb to the diffraction limit. The fluorescence image encodes the high frequency content as a down-mixed, moiré-like pattern. A series of images is required, wherein the 3D pattern is shifted and rotated, providing down-mixed data for a system of linear equations. Super-resolution is obtained by solving these equations. The speed with which the image series can be obtained can be a problem for the microscopy of living cells. Challenges include pattern-switching speeds, optical efficiency, wavefront quality and fringe contrast, fringe pitch optimization, and polarization issues. We will review some recent developments in 3D-SIM hardware with the goal of super-resolved z-stacks of motile cells.

  12. Reduction of Thermal Conductivity by Nanoscale 3D Phononic Crystal

    PubMed Central

    Yang, Lina; Yang, Nuo; Li, Baowen

    2013-01-01

    We studied how the period length and the mass ratio affect the thermal conductivity of isotopic nanoscale three-dimensional (3D) phononic crystal of Si. Simulation results by equilibrium molecular dynamics show isotopic nanoscale 3D phononic crystals can significantly reduce the thermal conductivity of bulk Si at high temperature (1000 K), which leads to a larger ZT than unity. The thermal conductivity decreases as the period length and mass ratio increases. The phonon dispersion curves show an obvious decrease of group velocities in 3D phononic crystals. The phonon's localization and band gap is also clearly observed in spectra of normalized inverse participation ratio in nanoscale 3D phononic crystal. PMID:23378898

  13. Reduction of thermal conductivity by nanoscale 3D phononic crystal.

    PubMed

    Yang, Lina; Yang, Nuo; Li, Baowen

    2013-01-01

    We studied how the period length and the mass ratio affect the thermal conductivity of isotopic nanoscale three-dimensional (3D) phononic crystal of Si. Simulation results by equilibrium molecular dynamics show isotopic nanoscale 3D phononic crystals can significantly reduce the thermal conductivity of bulk Si at high temperature (1000 K), which leads to a larger ZT than unity. The thermal conductivity decreases as the period length and mass ratio increases. The phonon dispersion curves show an obvious decrease of group velocities in 3D phononic crystals. The phonon's localization and band gap is also clearly observed in spectra of normalized inverse participation ratio in nanoscale 3D phononic crystal.

  14. Tomographic 3D-PIV and Applications

    NASA Astrophysics Data System (ADS)

    Elsinga, Gerrit E.; Wieneke, Bernhard; Scarano, Fulvio; Schröder, Andreas

    Tomographic particle image velocimetry is a 3D PIV technique based on the illumination, recording, reconstruction and analysis of tracer-particle motion within a three-dimensional measurement volume. The recently developed technique makes use of several simultaneous views of the illuminated particles, typically 4, and their three-dimensional reconstruction as a light-intensity distribution by means of optical tomography. The reconstruction is performed with the MART algorithm (multiplicative algebraic reconstruction technique), yielding a 3D distribution of light intensity discretized over an array of voxels. The reconstructed tomogram pair is then analyzed by means of 3D crosscorrelation with an iterative multigrid volume-deformation technique, returning the three-component velocity vector distribution over the measurement volume. The implementation of the tomographic technique in time-resolved mode by means of high repetition rate PIV hardware has the capability to yield 4D velocity information. The first part of the chapter describes the operation principles and gives a detailed assessment of the tomographic reconstruction algorithm performance based upon a computer-simulated experiment. The second part of the chapter proposes four applications on two flow cases: 1. the transitional wake behind a circular cylinder; 2. the turbulent boundary layer developing over a flat plate. For the first case, experiments in air at ReD = 2700 are described together with the experimental assessment of the tomographic reconstruction accuracy. In this experiment a direct comparison is made between the results obtained by tomographic PIV and stereo-PIV. Experiments conducted in a water facility on the cylinder wake shows the extension of the technique to time-resolved measurements in water at ReD = 540 by means of a low repetition rate PIV system. A high data yield is obtained using high-resolution cameras (2k × 2k pixels) returning 650k vectors per volume. Measurements of the

  15. Development and Calibration of New 3-D Vector VSP Imaging Technology: Vinton Salt Dome, LA

    SciTech Connect

    Kurt J. Marfurt; Hua-Wei Zhou; E. Charlotte Sullivan

    2004-09-01

    Vinton salt dome is located in Southwestern Louisiana, in Calcasieu Parish. Tectonically, the piercement dome is within the salt dome minibasin province. The field has been in production since 1901, with most of the production coming from Miocene and Oligocene sands. The goal of our project was to develop and calibrate new processing and interpretation technology to fully exploit the information available from a simultaneous 3-D surface seismic survey and 3-C, 3-D vertical seismic profile (VSP) survey over the dome. More specifically the goal was to better image salt dome flanks and small, reservoir-compartmentalizing faults. This new technology has application to mature salt-related fields across the Gulf Coast. The primary focus of our effort was to develop, apply, and assess the limitations of new 3-C, 3-D wavefield separation and imaging technology that could be used to image aliased, limited-aperture, vector VSP data. Through 2-D and 3-D full elastic modeling, we verified that salt flank reflections exist in the horizontally-traveling portion of the wavefield rather than up- and down-going portions of the wavefield, thereby explaining why many commercial VSP processing flow failed. Since the P-wave reflections from the salt flank are measured primarily on the horizontal components while P-wave reflections from deeper sedimentary horizons are measured primarily on the vertical component, a true vector VSP analysis was needed. We developed an antialiased discrete Radon transform filter to accurately model P- and S-wave data components measured by the vector VSP. On-the-fly polarization filtering embedded in our Kirchhoff imaging algorithm was effective in separating PP from PS wave images. By the novel application of semblance-weighted filters, we were able to suppress many of the migration artifacts associated with low fold, sparse VSP acquisition geometries. To provide a better velocity/depth model, we applied 3-D prestack depth migration to the surface data

  16. 3D Printing of Graphene Aerogels.

    PubMed

    Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong

    2016-04-06

    3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (<10 mg cm(-3) ) 3D printed graphene aerogel presents superelastic and high electrical conduction.

  17. Quasi 3D dispersion experiment

    NASA Astrophysics Data System (ADS)

    Bakucz, P.

    2003-04-01

    This paper studies the problem of tracer dispersion in a coloured fluid flowing through a two-phase 3D rough channel-system in a 40 cm*40 cm plexi-container filled by homogen glass fractions and colourless fluid. The unstable interface between the driving coloured fluid and the colourless fluid develops viscous fingers with a fractal structure at high capillary number. Five two-dimensional fractal fronts have been observed at the same time using four cameras along the vertical side-walls and using one camera located above the plexi-container. In possession of five fronts the spatial concentration contours are determined using statistical models. The concentration contours are self-affine fractal curves with a fractal dimension D=2.19. This result is valid for disperison at high Péclet numbers.

  18. ShowMe3D

    SciTech Connect

    Sinclair, Michael B

    2012-01-05

    ShowMe3D is a data visualization graphical user interface specifically designed for use with hyperspectral image obtained from the Hyperspectral Confocal Microscope. The program allows the user to select and display any single image from a three dimensional hyperspectral image stack. By moving a slider control, the user can easily move between images of the stack. The user can zoom into any region of the image. The user can select any pixel or region from the displayed image and display the fluorescence spectrum associated with that pixel or region. The user can define up to 3 spectral filters to apply to the hyperspectral image and view the image as it would appear from a filter-based confocal microscope. The user can also obtain statistics such as intensity average and variance from selected regions.

  19. 3D Printed Shelby Cobra

    ScienceCinema

    Love, Lonnie

    2016-11-02

    ORNL's newly printed 3D Shelby Cobra was showcased at the 2015 NAIAS in Detroit. This "laboratory on wheels" uses the Shelby Cobra design, celebrating the 50th anniversary of this model and honoring the first vehicle to be voted a national monument. The Shelby was printed at the Department of Energy’s Manufacturing Demonstration Facility at ORNL using the BAAM (Big Area Additive Manufacturing) machine and is intended as a “plug-n-play” laboratory on wheels. The Shelby will allow research and development of integrated components to be tested and enhanced in real time, improving the use of sustainable, digital manufacturing solutions in the automotive industry.

  20. Tangential Velocity Measurement Using Interferometric MTI Radar

    SciTech Connect

    DOERRY, ARMIN W.; MILESHOSKY, BRIAN P.; BICKEL, DOUGLAS L.

    2002-11-01

    An Interferometric Moving Target Indicator radar can be used to measure the tangential velocity component of a moving target. Multiple baselines, along with the conventional radial velocity measurement, allow estimating the true 3-D velocity vector of a target.

  1. 3-D object-oriented image analysis of geophysical data

    NASA Astrophysics Data System (ADS)

    Fadel, I.; Kerle, N.; van der Meijde, M.

    2014-07-01

    Geophysical data are the main source of information about the subsurface. Geophysical techniques are, however, highly non-unique in determining specific physical parameters and boundaries of subsurface objects. To obtain actual physical information, an inversion process is often applied, in which measurements at or above the Earth surface are inverted into a 2- or 3-D subsurface spatial distribution of the physical property. Interpreting these models into structural objects, related to physical processes, requires a priori knowledge and expert analysis which is susceptible to subjective choices and is therefore often non-repeatable. In this research, we implemented a recently introduced object-based approach to interpret the 3-D inversion results of a single geophysical technique using the available a priori information and the physical and geometrical characteristics of the interpreted objects. The introduced methodology is semi-automatic and repeatable, and allows the extraction of subsurface structures using 3-D object-oriented image analysis (3-D OOA) in an objective knowledge-based classification scheme. The approach allows for a semi-objective setting of thresholds that can be tested and, if necessary, changed in a very fast and efficient way. These changes require only changing the thresholds used in a so-called ruleset, which is composed of algorithms that extract objects from a 3-D data cube. The approach is tested on a synthetic model, which is based on a priori knowledge on objects present in the study area (Tanzania). Object characteristics and thresholds were well defined in a 3-D histogram of velocity versus depth, and objects were fully retrieved. The real model results showed how 3-D OOA can deal with realistic 3-D subsurface conditions in which the boundaries become fuzzy, the object extensions become unclear and the model characteristics vary with depth due to the different physical conditions. As expected, the 3-D histogram of the real data was

  2. Seismic noise frequency dependent P and S wave sources

    NASA Astrophysics Data System (ADS)

    Stutzmann, E.; Schimmel, M.; Gualtieri, L.; Farra, V.; Ardhuin, F.

    2013-12-01

    Seismic noise in the period band 3-10 sec is generated in the oceans by the interaction of ocean waves. Noise signal is dominated by Rayleigh waves but body waves can be extracted using a beamforming approach. We select the TAPAS array deployed in South Spain between June 2008 and September 2009 and we use the vertical and horizontal components to extract noise P and S waves, respectively. Data are filtered in narrow frequency bands and we select beam azimuths and slownesses that correspond to the largest continuous sources per day. Our procedure automatically discard earthquakes which are localized during short time durations. Using this approach, we detect many more noise P-waves than S-waves. Source locations are determined by back-projecting the detected slowness/azimuth. P and S waves are generated in nearby areas and both source locations are frequency dependent. Long period sources are dominantly in the South Atlantic and Indian Ocean whereas shorter period sources are rather in the North Atlantic Ocean. We further show that the detected S-waves are dominantly Sv-waves. We model the observed body waves using an ocean wave model that takes into account all possible wave interactions including coastal reflection. We use the wave model to separate direct and multiply reflected phases for P and S waves respectively. We show that in the South Atlantic the complex source pattern can be explained by the existence of both coastal and pelagic sources whereas in the North Atlantic most body wave sources are pelagic. For each detected source, we determine the equivalent source magnitude which is compared to the model.

  3. Scattering of S waves diffracted at the core-mantle boundary: forward modelling

    NASA Astrophysics Data System (ADS)

    Emery, Valérie; Maupin, Valérie; Nataf, Henri-Claude

    1999-11-01

    The lowermost 200-300 km of the Earth's mantle, known as the D'' layer, is an extremely complex and heterogeneous region where transfer processes between the core and the mantle take place. Diffracted S waves propagate over large distances and are very sensitive to the velocity structure of this region. Strong variations of ampli-tudes and waveforms are observed on recordings from networks of broad-band seismic stations. We perform forward modelling of diffracted S waves in laterally heterogeneous structures in order to analyse whether or not these observations can be related to lateral inhomogeneities in D''. We combine the diffraction due to the core and the scattering due to small-scale volumetric heterogeneities (10-100 km) by coupling single scattering (Born approximation) with the Langer approximation, which describes Sdiff wave propagation. The influence on the direct as well as on the scattered wavefields of the CMB as well as of possible tunnelling in the core or in D'' is fully accounted for. The SH and the SV components of the diffracted waves are analysed, as well as their coupling. The modelling is applied in heterogeneous models with different geometries: isolated heterogeneities, vertical cylinders, horizontal inhomogeneities and random media. Amplitudes of scattered waves are weak and only velocity perturbations of the order of 10 per cent over a volume of 240 x 240 x 300 km3 produce visible effects on seismograms. The two polarizations of Sdiff have different radial sensitivities, the SH components being more sensitive to heterogeneities closer to the CMB. However, we do not observe significant time-shifts between the two components similar to those produced by anisotropy. The long-period Sdiff have a poor lateral resolution and average the velocity perturbations in their Fresnel zone. Random small-scale heterogeneities with +/- 10 per cent velocity contrast in the layer therefore have little effect on Sdiff, in contrast to their effect on PKIKP.

  4. 3D Kitaev spin liquids

    NASA Astrophysics Data System (ADS)

    Hermanns, Maria

    The Kitaev honeycomb model has become one of the archetypal spin models exhibiting topological phases of matter, where the magnetic moments fractionalize into Majorana fermions interacting with a Z2 gauge field. In this talk, we discuss generalizations of this model to three-dimensional lattice structures. Our main focus is the metallic state that the emergent Majorana fermions form. In particular, we discuss the relation of the nature of this Majorana metal to the details of the underlying lattice structure. Besides (almost) conventional metals with a Majorana Fermi surface, one also finds various realizations of Dirac semi-metals, where the gapless modes form Fermi lines or even Weyl nodes. We introduce a general classification of these gapless quantum spin liquids using projective symmetry analysis. Furthermore, we briefly outline why these Majorana metals in 3D Kitaev systems provide an even richer variety of Dirac and Weyl phases than possible for electronic matter and comment on possible experimental signatures. Work done in collaboration with Kevin O'Brien and Simon Trebst.

  5. 3D multiplexed immunoplasmonics microscopy

    NASA Astrophysics Data System (ADS)

    Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel

    2016-07-01

    Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed

  6. Crowdsourcing Based 3d Modeling

    NASA Astrophysics Data System (ADS)

    Somogyi, A.; Barsi, A.; Molnar, B.; Lovas, T.

    2016-06-01

    Web-based photo albums that support organizing and viewing the users' images are widely used. These services provide a convenient solution for storing, editing and sharing images. In many cases, the users attach geotags to the images in order to enable using them e.g. in location based applications on social networks. Our paper discusses a procedure that collects open access images from a site frequently visited by tourists. Geotagged pictures showing the image of a sight or tourist attraction are selected and processed in photogrammetric processing software that produces the 3D model of the captured object. For the particular investigation we selected three attractions in Budapest. To assess the geometrical accuracy, we used laser scanner and DSLR as well as smart phone photography to derive reference values to enable verifying the spatial model obtained from the web-album images. The investigation shows how detailed and accurate models could be derived applying photogrammetric processing software, simply by using images of the community, without visiting the site.

  7. Evidence for serpentinization of the Ionian upper mantle from simultaneous inversion of P- and S-wave arrival times

    NASA Astrophysics Data System (ADS)

    D'Alessandro, Antonino; Mangano, Giorgio; D'Anna, Giuseppe; Scudero, Salvatore

    2016-12-01

    Simultaneous inversion of P- and S-wave arrival times, collected during a 3-years Ocean Bottom Seismometer with Hydrophone (OBS/H) monitoring campaign, yields 1D P- and S-wave velocity models for the Ionian lithosphere (Central Mediterranean). The 1D model highlights the presence, in the Ionian upper mantle, of two layers characterized by high seismic P-wave velocity (S1 and S2, 6.3-6.7 and 7.5 km/s, respectively). These two layers, with thicknesses of about 3.3 km and 5 km, respectively, and ranging from ∼8 to ∼16 km in depth, are characterized by low S-wave velocity (S1 = 3.05-3.2 km/s, S2 = 3.85 km/s) and high values of VP/VS (S1 = 2.06-2.09, S2 = 1.95). This is a characteristic feature, often encountered in passive margins and is generally interpreted as partly serpentinized peridotite. The VP, VS and VP/VS values of S1 are consistent with 55-65% of serpentinization of the upper mantle, while the S2 ones are consistent with 15-25% of serpentinization. This research provides a crucial hint about the debated nature of the Ionian crust, suggesting its oceanic structure.

  8. 3D geological to geophysical modelling and seismic wave propagation simulation: a case study from the Lalor Lake VMS (Volcanogenic Massive Sulphides) mining camp

    NASA Astrophysics Data System (ADS)

    Miah, Khalid; Bellefleur, Gilles

    2014-05-01

    The global demand for base metals, uranium and precious metals has been pushing mineral explorations at greater depth. Seismic techniques and surveys have become essential in finding and extracting mineral rich ore bodies, especially for deep VMS mining camps. Geophysical parameters collected from borehole logs and laboratory measurements of core samples provide preliminary information about the nature and type of subsurface lithologic units. Alteration halos formed during the hydrothermal alteration process contain ore bodies, which are of primary interests among geologists and mining industries. It is known that the alteration halos are easier to detect than the ore bodies itself. Many 3D geological models are merely projection of 2D surface geology based on outcrop inspections and geochemical analysis of a small number of core samples collected from the area. Since a large scale 3D multicomponent seismic survey can be prohibitively expensive, performance analysis of such geological models can be helpful in reducing exploration costs. In this abstract, we discussed challenges and constraints encountered in geophysical modelling of ore bodies and surrounding geologic structures from the available coarse 3D geological models of the Lalor Lake mining camp, located in northern Manitoba, Canada. Ore bodies in the Lalor lake VMS camp are rich in gold, zinc, lead and copper, and have an approximate weight of 27 Mt. For better understanding of physical parameters of these known ore bodies and potentially unknown ones at greater depth, we constructed a fine resolution 3D seismic model with dimensions: 2000 m (width), 2000 m (height), and 1500 m (vertical depth). Seismic properties (P-wave, S-wave velocities, and density) were assigned based on a previous rock properties study of the same mining camp. 3D finite-difference elastic wave propagation simulation was performed in the model using appropriate parameters. The generated synthetic 3D seismic data was then compared to

  9. Coherence of Teleseismic P and S waves Across the Transportable Array

    NASA Astrophysics Data System (ADS)

    Langston, C. A.

    2012-12-01

    Design of large-aperture broadband arrays and array stacking of waveforms for receiver function studies critically depend on the coherence of waveforms across an array. The coherence of teleseismic P and S waves in the frequency band of 0.05 to 1.6 Hz has been examined using high signal-to-noise teleseisms recorded by the USArray Transportable Array. Instrument-corrected, time-windowed, and rotated P and S waves were filtered in five, single-octave frequency bands and then correlated to determine coherence in each band. The normalized correlation coefficient is used as a measure of relative coherence and plotted as a function of interstation distance, which is used as a proxy for horizontal wavelength. Up to ~100,000 unique station correlation pairs can be found for vertical, radial, and transverse component P and S. Results for the M7.1 2012 March 25 Maule, Chile, earthquake show that teleseismic P waves for stations greater than 30 degrees in distance are highly correlated for interstation distances of up to 10 wavelengths and greater in the band 0.05-0.08 Hz (Correlation coefficients > 0.8). Coherence drops off sharply for the 0.8-1.6Hz band to about 2 wavelengths or less. Coherence shows greater scatter and somewhat smaller values for teleseismic radial and transverse component S-waves for the 0.05-0.2Hz frequency band, with incoherence at higher frequency. The M7.4 2012 March 20 Oaxaca, Mexico, earthquake was generally less than 30 degrees distance from the TA and showed uniformly lower coherence values for P-waves for frequencies greater than 0.2Hz. The relative incoherence between seismic stations is mostly a measure of the variability in velocity structure of the earth. These results show that teleseismic P and S waves are highly coherent over large distances for deep mantle ray turning points but, not surprisingly, wave propagation through the upper mantle shows waveform complexity and velocity heterogeneity. This characteristic of wave propagation in the

  10. New Reconstruction Accuracy Metric for 3D PIV

    NASA Astrophysics Data System (ADS)

    Bajpayee, Abhishek; Techet, Alexandra

    2015-11-01

    Reconstruction for 3D PIV typically relies on recombining images captured from different viewpoints via multiple cameras/apertures. Ideally, the quality of reconstruction dictates the accuracy of the derived velocity field. A reconstruction quality parameter Q is commonly used as a measure of the accuracy of reconstruction algorithms. By definition, a high Q value requires intensity peak levels and shapes in the reconstructed and reference volumes to be matched. We show that accurate velocity fields rely only on the peak locations in the volumes and not on intensity peak levels and shapes. In synthetic aperture (SA) PIV reconstructions, the intensity peak shapes and heights vary with the number of cameras and due to spatial/temporal particle intensity variation respectively. This lowers Q but not the accuracy of the derived velocity field. We introduce a new velocity vector correlation factor Qv as a metric to assess the accuracy of 3D PIV techniques, which provides a better indication of algorithm accuracy. For SAPIV, the number of cameras required for a high Qv are lower than that for a high Q. We discuss Qv in the context of 3D PIV and also present a preliminary comparison of the performance of TomoPIV and SAPIV based on Qv.

  11. Local Earthquake Velocity and Attenuation Tomography of the Jalisco, Mexico Region

    NASA Astrophysics Data System (ADS)

    Watkins, W. D.; Thurber, C. H.; Abbott, E. R.; Brudzinski, M.; Grand, S. P.

    2015-12-01

    The states of Jalisco, Colima, and Michoacan in western Mexico overlie the boundary of the subducting Rivera and Cocos plates, presenting an appealing target for seismological inquiry to better understand the resulting mantle flow and regional volcanism. The different dips between the subducting plates is thought to provide a mantle conduit that has contributed to the Colima Volcanic Complex, but there is considerable debate on the shallowness of the Rivera plate and width of the resulting conduit. With data from the Mapping the Rivera Subduction Zone (MARS) and Colima Deep Seismic Experiment (CODEX) networks, two temporary broadband arrays deployed in the region between 2006-2008, we invert for three-dimensional P- and S- wave velocity and later attenuation structure of the upper ~80 km of the crust and mantle in the Jalisco region. We improve upon previous tomography work by utilizing double-difference tomography, which enables the use of higher-accuracy differential times to sharpen the earthquake locations, and the inclusion of S-wave data. Current models that utilize only analyst-picked phase arrivals from 590 earthquakes yield P-wave high velocity anomalies that suggest a slab under the coastal regions at 15-25 km depth, and low velocity anomalies that may be related to Colima Volcano or other geologic features. Most of the S-wave model is poorly resolved. We will use a newly developed auto-picker to attempt to substantially increase the size of the S-wave dataset and to a lesser extent the P wave dataset, in order to densify ray coverage and improve model resolution. Additionally, we plan to employ the waveforms from this expanded dataset to compute a path attenuation operator for each arrival, which will then be used to invert for 3D P and S-wave attenuation models. The attenuation models combined with the velocity models will provide multiple constraints on physical properties of the crust in this region as well as those of specific geologic features.

  12. A comparative study between a rectilinear 3-D seismic survey and a concentric-circle 3-D seismic survey

    SciTech Connect

    Maldonado, B.; Hussein, H.S.

    1994-12-31

    Due to the rectilinear nature of the previous 3D seismic survey, the details necessary for proper interpretation were absent. Theoretically, concentric 3D seismic technology may provide an avenue for gaining more and higher quality data coverage. Problems associated with recording a rectilinear 3D seismic grid over the salt dome in this area have created the need to investigate the use of such procedures as the concentric-circle 3D seismic acquisition technique. The difficulty of imaging salt dome flanks with conventional rectilinear 3D seismic may be a result of the inability to precisely predict the lateral velocity-field variation adjacent to both salt and sediments. The dramatic difference in the interval velocities of salt and sediments causes the returning ray to severely deviate from being a hyperbolic path. This hampers the ability to predict imaging points near the salt/sediment interface. Perhaps the most difficult areas to image with rectilinear seismic surveys are underneath salt overhangs. Modeling suggests that a significant increase in the number of rays captured from beneath a salt overhang can be achieved with the concentric-circle method. This paper demonstrates the use of the ``circle shoot`` on a survey conducted over a salt dome in the Gulf of Mexico. A total of 80 concentric circles cover an area which is equivalent to 31,000 acres. The final post-stack data were sorted into bins with dimensions of 25 meters by 25 meters. A comparison of 3D rectilinear shooting vs. 3D concentric circle shooting over the same area will show an improvement in data quality and signal-to-noise characteristics.

  13. [3D emulation of epicardium dynamic mapping].

    PubMed

    Lu, Jun; Yang, Cui-Wei; Fang, Zu-Xiang

    2005-03-01

    In order to realize epicardium dynamic mapping of the whole atria, 3-D graphics are drawn with OpenGL. Some source codes are introduced in the paper to explain how to produce, read, and manipulate 3-D model data.

  14. An interactive multiview 3D display system

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaoxing; Geng, Zheng; Zhang, Mei; Dong, Hui

    2013-03-01

    The progresses in 3D display systems and user interaction technologies will help more effective 3D visualization of 3D information. They yield a realistic representation of 3D objects and simplifies our understanding to the complexity of 3D objects and spatial relationship among them. In this paper, we describe an autostereoscopic multiview 3D display system with capability of real-time user interaction. Design principle of this autostereoscopic multiview 3D display system is presented, together with the details of its hardware/software architecture. A prototype is built and tested based upon multi-projectors and horizontal optical anisotropic display structure. Experimental results illustrate the effectiveness of this novel 3D display and user interaction system.

  15. Laser Based 3D Volumetric Display System

    DTIC Science & Technology

    1993-03-01

    Literature, Costa Mesa, CA July 1983. 3. "A Real Time Autostereoscopic Multiplanar 3D Display System", Rodney Don Williams, Felix Garcia, Jr., Texas...8217 .- NUMBERS LASER BASED 3D VOLUMETRIC DISPLAY SYSTEM PR: CD13 0. AUTHOR(S) PE: N/AWIU: DN303151 P. Soltan, J. Trias, W. Robinson, W. Dahlke 7...laser generated 3D volumetric images on a rotating double helix, (where the 3D displays are computer controlled for group viewing with the naked eye

  16. True 3d Images and Their Applications

    NASA Astrophysics Data System (ADS)

    Wang, Z.; wang@hzgeospace., zheng.

    2012-07-01

    A true 3D image is a geo-referenced image. Besides having its radiometric information, it also has true 3Dground coordinates XYZ for every pixels of it. For a true 3D image, especially a true 3D oblique image, it has true 3D coordinates not only for building roofs and/or open grounds, but also for all other visible objects on the ground, such as visible building walls/windows and even trees. The true 3D image breaks the 2D barrier of the traditional orthophotos by introducing the third dimension (elevation) into the image. From a true 3D image, for example, people will not only be able to read a building's location (XY), but also its height (Z). true 3D images will fundamentally change, if not revolutionize, the way people display, look, extract, use, and represent the geospatial information from imagery. In many areas, true 3D images can make profound impacts on the ways of how geospatial information is represented, how true 3D ground modeling is performed, and how the real world scenes are presented. This paper first gives a definition and description of a true 3D image and followed by a brief review of what key advancements of geospatial technologies have made the creation of true 3D images possible. Next, the paper introduces what a true 3D image is made of. Then, the paper discusses some possible contributions and impacts the true 3D images can make to geospatial information fields. At the end, the paper presents a list of the benefits of having and using true 3D images and the applications of true 3D images in a couple of 3D city modeling projects.

  17. 3D Printing and Digital Rock Physics for Geomaterials

    NASA Astrophysics Data System (ADS)

    Martinez, M. J.; Yoon, H.; Dewers, T. A.

    2015-12-01

    Imaging techniques for the analysis of porous structures have revolutionized our ability to quantitatively characterize geomaterials. Digital representations of rock from CT images and physics modeling based on these pore structures provide the opportunity to further advance our quantitative understanding of fluid flow, geomechanics, and geochemistry, and the emergence of coupled behaviors. Additive manufacturing, commonly known as 3D printing, has revolutionized production of custom parts with complex internal geometries. For the geosciences, recent advances in 3D printing technology may be co-opted to print reproducible porous structures derived from CT-imaging of actual rocks for experimental testing. The use of 3D printed microstructure allows us to surmount typical problems associated with sample-to-sample heterogeneity that plague rock physics testing and to test material response independent from pore-structure variability. Together, imaging, digital rocks and 3D printing potentially enables a new workflow for understanding coupled geophysical processes in a real, but well-defined setting circumventing typical issues associated with reproducibility, enabling full characterization and thus connection of physical phenomena to structure. In this talk we will discuss the possibilities that these technologies can bring to geosciences and present early experiences with coupled multiscale experimental and numerical analysis using 3D printed fractured rock specimens. In particular, we discuss the processes of selection and printing of transparent fractured specimens based on 3D reconstruction of micro-fractured rock to study fluid flow characterization and manipulation. Micro-particle image velocimetry is used to directly visualize 3D single and multiphase flow velocity in 3D fracture networks. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U

  18. 3D Printing and Its Urologic Applications

    PubMed Central

    Soliman, Youssef; Feibus, Allison H; Baum, Neil

    2015-01-01

    3D printing is the development of 3D objects via an additive process in which successive layers of material are applied under computer control. This article discusses 3D printing, with an emphasis on its historical context and its potential use in the field of urology. PMID:26028997

  19. Teaching Geography with 3-D Visualization Technology

    ERIC Educational Resources Information Center

    Anthamatten, Peter; Ziegler, Susy S.

    2006-01-01

    Technology that helps students view images in three dimensions (3-D) can support a broad range of learning styles. "Geo-Wall systems" are visualization tools that allow scientists, teachers, and students to project stereographic images and view them in 3-D. We developed and presented 3-D visualization exercises in several undergraduate courses.…

  20. Expanding Geometry Understanding with 3D Printing

    ERIC Educational Resources Information Center

    Cochran, Jill A.; Cochran, Zane; Laney, Kendra; Dean, Mandi

    2016-01-01

    With the rise of personal desktop 3D printing, a wide spectrum of educational opportunities has become available for educators to leverage this technology in their classrooms. Until recently, the ability to create physical 3D models was well beyond the scope, skill, and budget of many schools. However, since desktop 3D printers have become readily…

  1. Beowulf 3D: a case study

    NASA Astrophysics Data System (ADS)

    Engle, Rob

    2008-02-01

    This paper discusses the creative and technical challenges encountered during the production of "Beowulf 3D," director Robert Zemeckis' adaptation of the Old English epic poem and the first film to be simultaneously released in IMAX 3D and digital 3D formats.

  2. 3D Flow Visualization Using Texture Advection

    NASA Technical Reports Server (NTRS)

    Kao, David; Zhang, Bing; Kim, Kwansik; Pang, Alex; Moran, Pat (Technical Monitor)

    2001-01-01

    Texture advection is an effective tool for animating and investigating 2D flows. In this paper, we discuss how this technique can be extended to 3D flows. In particular, we examine the use of 3D and 4D textures on 3D synthetic and computational fluid dynamics flow fields.

  3. Predicting Strong Ground-Motion Seismograms for Magnitude 9 Cascadia Earthquakes Using 3D Simulations with High Stress Drop Sub-Events

    NASA Astrophysics Data System (ADS)

    Frankel, A. D.; Wirth, E. A.; Stephenson, W. J.; Moschetti, M. P.; Ramirez-Guzman, L.

    2015-12-01

    We have produced broadband (0-10 Hz) synthetic seismograms for magnitude 9.0 earthquakes on the Cascadia subduction zone by combining synthetics from simulations with a 3D velocity model at low frequencies (≤ 1 Hz) with stochastic synthetics at high frequencies (≥ 1 Hz). We use a compound rupture model consisting of a set of M8 high stress drop sub-events superimposed on a background slip distribution of up to 20m that builds relatively slowly. The 3D simulations were conducted using a finite difference program and the finite element program Hercules. The high-frequency (≥ 1 Hz) energy in this rupture model is primarily generated in the portion of the rupture with the M8 sub-events. In our initial runs, we included four M7.9-8.2 sub-events similar to those that we used to successfully model the strong ground motions recorded from the 2010 M8.8 Maule, Chile earthquake. At periods of 2-10 s, the 3D synthetics exhibit substantial amplification (about a factor of 2) for sites in the Puget Lowland and even more amplification (up to a factor of 5) for sites in the Seattle and Tacoma sedimentary basins, compared to rock sites outside of the Puget Lowland. This regional and more localized basin amplification found from the simulations is supported by observations from local earthquakes. There are substantial variations in the simulated M9 time histories and response spectra caused by differences in the hypocenter location, slip distribution, down-dip extent of rupture, coherence of the rupture front, and location of sub-events. We examined the sensitivity of the 3D synthetics to the velocity model of the Seattle basin. We found significant differences in S-wave focusing and surface wave conversions between a 3D model of the basin from a spatially-smoothed tomographic inversion of Rayleigh-wave phase velocities and a model that has an abrupt southern edge of the Seattle basin, as observed in seismic reflection profiles.

  4. 3-D Perspective Pasadena, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This perspective view shows the western part of the city of Pasadena, California, looking north towards the San Gabriel Mountains. Portions of the cities of Altadena and La Canada, Flintridge are also shown. The image was created from three datasets: the Shuttle Radar Topography Mission (SRTM) supplied the elevation data; Landsat data from November 11, 1986 provided the land surface color (not the sky) and U.S. Geological Survey digital aerial photography provides the image detail. The Rose Bowl, surrounded by a golf course, is the circular feature at the bottom center of the image. The Jet Propulsion Laboratory is the cluster of large buildings north of the Rose Bowl at the base of the mountains. A large landfill, Scholl Canyon, is the smooth area in the lower left corner of the scene. This image shows the power of combining data from different sources to create planning tools to study problems that affect large urban areas. In addition to the well-known earthquake hazards, Southern California is affected by a natural cycle of fire and mudflows. Wildfires strip the mountains of vegetation, increasing the hazards from flooding and mudflows for several years afterwards. Data such as shown on this image can be used to predict both how wildfires will spread over the terrain and also how mudflows will be channeled down the canyons. The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission was designed to collect three dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency

  5. Exotic s-wave superconductivity in alkali-doped fullerides.

    PubMed

    Nomura, Yusuke; Sakai, Shiro; Capone, Massimo; Arita, Ryotaro

    2016-04-20

    Alkali-doped fullerides (A3C60 with A = K, Rb, Cs) show a surprising phase diagram, in which a high transition-temperature (Tc) s-wave superconducting state emerges next to a Mott insulating phase as a function of the lattice spacing. This is in contrast with the common belief that Mott physics and phonon-driven s-wave superconductivity are incompatible, raising a fundamental question on the mechanism of the high-Tc superconductivity. This article reviews recent ab initio calculations, which have succeeded in reproducing comprehensively the experimental phase diagram with high accuracy and elucidated an unusual cooperation between the electron-phonon coupling and the electron-electron interactions leading to Mott localization to realize an unconventional s-wave superconductivity in the alkali-doped fullerides. A driving force behind the exotic physics is unusual intramolecular interactions, characterized by the coexistence of a strongly repulsive Coulomb interaction and a small effectively negative exchange interaction. This is realized by a subtle energy balance between the coupling with the Jahn-Teller phonons and Hund's coupling within the C60 molecule. The unusual form of the interaction leads to a formation of pairs of up- and down-spin electrons on the molecules, which enables the s-wave pairing. The emergent superconductivity crucially relies on the presence of the Jahn-Teller phonons, but surprisingly benefits from the strong correlations because the correlations suppress the kinetic energy of the electrons and help the formation of the electron pairs, in agreement with previous model calculations. This confirms that the alkali-doped fullerides are a new type of unconventional superconductors, where the unusual synergy between the phonons and Coulomb interactions drives the high-Tc superconductivity.

  6. Exotic s-wave superconductivity in alkali-doped fullerides

    NASA Astrophysics Data System (ADS)

    Nomura, Yusuke; Sakai, Shiro; Capone, Massimo; Arita, Ryotaro

    2016-04-01

    Alkali-doped fullerides ({{A}3}{{\\text{C}}60} with A  =  K, Rb, Cs) show a surprising phase diagram, in which a high transition-temperature ({{T}\\text{c}} ) s-wave superconducting state emerges next to a Mott insulating phase as a function of the lattice spacing. This is in contrast with the common belief that Mott physics and phonon-driven s-wave superconductivity are incompatible, raising a fundamental question on the mechanism of the high-{{T}\\text{c}} superconductivity. This article reviews recent ab initio calculations, which have succeeded in reproducing comprehensively the experimental phase diagram with high accuracy and elucidated an unusual cooperation between the electron-phonon coupling and the electron-electron interactions leading to Mott localization to realize an unconventional s-wave superconductivity in the alkali-doped fullerides. A driving force behind the exotic physics is unusual intramolecular interactions, characterized by the coexistence of a strongly repulsive Coulomb interaction and a small effectively negative exchange interaction. This is realized by a subtle energy balance between the coupling with the Jahn-Teller phonons and Hund’s coupling within the {{\\text{C}}60} molecule. The unusual form of the interaction leads to a formation of pairs of up- and down-spin electrons on the molecules, which enables the s-wave pairing. The emergent superconductivity crucially relies on the presence of the Jahn-Teller phonons, but surprisingly benefits from the strong correlations because the correlations suppress the kinetic energy of the electrons and help the formation of the electron pairs, in agreement with previous model calculations. This confirms that the alkali-doped fullerides are a new type of unconventional superconductors, where the unusual synergy between the phonons and Coulomb interactions drives the high-{{T}\\text{c}} superconductivity.

  7. Non-isothermal 3D SDPD Simulations

    NASA Astrophysics Data System (ADS)

    Yang, Jun; Potami, Raffaele; Gatsonis, Nikolaos

    2012-11-01

    The study of fluids at micro and nanoscale requires new modeling and computational approaches. Smooth Particle Dissipative Dynamics (SDPD) is a mesh-free method that provides a bridge between the continuum equations of hydrodynamics embedded in the Smooth Particle Hydrodynamics approach and the molecular nature embedded in the DPD approach. SDPD is thermodynamically consistent, does not rely on arbitrary coefficients for its thermostat, involves realistic transport coefficients, and includes fluctuation terms. SDPD is implemented in our work for arbitrary 3D geometries with a methodology to model solid wall boundary conditions. We present simulations for isothermal flows for verification of our approach. The entropy equation is implemented with a velocity-entropy Verlet integration algorithm Flows with heat transfer are simulated for verification of the SDPD. We present also the self-diffusion coefficient derived from SDPD simulations for gases and liquids. Results show the scale dependence of self-diffusion coefficient on SDPD particle size. Computational Mathematics Program of the Air Force Office of Scientific Research under grant/contract number FA9550-06-1-0236.

  8. Nonlinear attenuation of S-waves and Love waves within ambient rock

    NASA Astrophysics Data System (ADS)

    Sleep, Norman H.; Erickson, Brittany A.

    2014-04-01

    obtain scaling relationships for nonlinear attenuation of S-waves and Love waves within sedimentary basins to assist numerical modeling. These relationships constrain the past peak ground velocity (PGV) of strong 3-4 s Love waves from San Andreas events within Greater Los Angeles, as well as the maximum PGV of future waves that can propagate without strong nonlinear attenuation. During each event, the shaking episode cracks the stiff, shallow rock. Over multiple events, this repeated damage in the upper few hundred meters leads to self-organization of the shear modulus. Dynamic strain is PGV divided by phase velocity, and dynamic stress is strain times the shear modulus. The frictional yield stress is proportional to depth times the effective coefficient of friction. At the eventual quasi-steady self-organized state, the shear modulus increases linearly with depth allowing inference of past typical PGV where rock over the damaged depth range barely reaches frictional failure. Still greater future PGV would cause frictional failure throughout the damaged zone, nonlinearly attenuating the wave. Assuming self-organization has taken place, estimated maximum past PGV within Greater Los Angeles Basins is 0.4-2.6 m s-1. The upper part of this range includes regions of accumulating sediments with low S-wave velocity that may have not yet compacted, rather than having been damaged by strong shaking. Published numerical models indicate that strong Love waves from the San Andreas Fault pass through Whittier Narrows. Within this corridor, deep drawdown of the water table from its currently shallow and preindustrial levels would nearly double PGV of Love waves reaching Downtown Los Angeles.

  9. P- and S-wave delays caused by thermal plumes

    NASA Astrophysics Data System (ADS)

    Maguire, Ross; Ritsema, Jeroen; van Keken, Peter E.; Fichtner, Andreas; Goes, Saskia

    2016-08-01

    Many studies have sought to seismically image plumes rising from the deep mantle in order to settle the debate about their presence and role in mantle dynamics, yet the predicted seismic signature of realistic plumes remains poorly understood. By combining numerical simulations of flow, mineral-physics constraints on the relationships between thermal anomalies and wave speeds, and spectral-element method based computations of seismograms, we estimate the delay times of teleseismic S and P waves caused by thermal plumes. Wave front healing is incomplete for seismic periods ranging from 10 s (relevant in traveltime tomography) to 40 s (relevant in waveform tomography). We estimate P-wave delays to be immeasurably small (<0.3 s). S-wave delays are larger than 0.4 s even for S waves crossing the conduits of the thinnest thermal plumes in our geodynamic models. At longer periods (>20 s), measurements of instantaneous phase misfit may be more useful in resolving narrow plume conduits. To detect S-wave delays of 0.4-0.8 s and the diagnostic frequency dependence imparted by plumes, it is key to minimize the influence of the heterogeneous crust and upper mantle. We argue that seismic imaging of plumes will advance significantly if data from wide-aperture ocean-bottom networks were available since, compared to continents, the oceanic crust and upper mantle are relatively simple.

  10. Advanced global P and S wave body wave tomography for monitoring applications

    NASA Astrophysics Data System (ADS)

    Simmons, Nathan; Myers, Stephen; Johannesson, Gardar; Matzel, Eric; Grand, Stephen

    2016-04-01

    We continue to develop more advanced models of Earth's global seismic structure, specifically focused on improving predictive capabilities for future seismic events (Simmons et al. 2011, 2012, 2015). Our most recent rendition combines high-quality P and S wave body wave travel times into a joint (simultaneous) inversion process to tomographically image Earth's crust and mantle (Simmons et al. 2015). The new model (LLNL-G3D-JPS) consists of 59 surfaces and ~1.6 million model nodes from the surface to the core-mantle boundary, overlaying a 1-D outer and inner core model. The model architecture is aspherical and we directly incorporate Earth's expected hydrostatic shape (ellipticity and mantle stretching). We also explicitly honor surface undulations including the Moho, several internal crustal units, and the upper mantle transition zone undulations as predicated by previous studies. The explicit Earth model design allows for accurate travel time computation using our unique 3-D ray tracing algorithms, capable of tracing more than 20 distinct seismic phases including crustal, regional, teleseismic, and core phases. Thus, we can now incorporate certain secondary (and sometimes exotic) phases into source location determination and other analyses. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-680505.

  11. An Evolutionary S-wave Model of the Earth Upper Mantle and Transition Zone

    NASA Astrophysics Data System (ADS)

    Debayle, E.; Dubuffet, F.; Durand, S.

    2015-12-01

    We present 3D2015_03Sv, an evolutionary S-wave model of the upper mantle. At the time of submitting this abstract, the model is based on the waveform modeling of most Rayleigh waves recorded between 1976 and March 2015, and includes 1,330,210 fundamental and higher mode Rayleigh waveforms analyzed at periods between 40 and 400 s. The use of approximate forward theory and modeling allows updating the model with new data on a regular basis, a few days after the publication of the monthly centroid moment tensor (CMT) catalog issued at the Lamont-Doherty Earth Observatory of Columbia University. 3D2015_03Sv contains azimuthal anisotropy and achieves a lateral resolution of ~600 km in the upper mantle. Comparison with other seismic models shows that in the uppermost 200 km, the use of massive datasets with large redundancies allows to average errors, so that it is possible to build models that are consistent up to degree 60. In the transition zone, the number of data decreases and the effect of modeling choices is important. The most recent seismic models agree up to degree 15, which represents an improvement compared to the previous generation of models.

  12. Case study: Beauty and the Beast 3D: benefits of 3D viewing for 2D to 3D conversion

    NASA Astrophysics Data System (ADS)

    Handy Turner, Tara

    2010-02-01

    From the earliest stages of the Beauty and the Beast 3D conversion project, the advantages of accurate desk-side 3D viewing was evident. While designing and testing the 2D to 3D conversion process, the engineering team at Walt Disney Animation Studios proposed a 3D viewing configuration that not only allowed artists to "compose" stereoscopic 3D but also improved efficiency by allowing artists to instantly detect which image features were essential to the stereoscopic appeal of a shot and which features had minimal or even negative impact. At a time when few commercial 3D monitors were available and few software packages provided 3D desk-side output, the team designed their own prototype devices and collaborated with vendors to create a "3D composing" workstation. This paper outlines the display technologies explored, final choices made for Beauty and the Beast 3D, wish-lists for future development and a few rules of thumb for composing compelling 2D to 3D conversions.

  13. Mini 3D for shallow gas reconnaissance

    SciTech Connect

    Vallieres, T. des; Enns, D.; Kuehn, H.; Parron, D.; Lafet, Y.; Van Hulle, D.

    1996-12-31

    The Mini 3D project was undertaken by TOTAL and ELF with the support of CEPM (Comite d`Etudes Petrolieres et Marines) to define an economical method of obtaining 3D seismic HR data for shallow gas assessment. An experimental 3D survey was carried out with classical site survey techniques in the North Sea. From these data 19 simulations, were produced to compare different acquisition geometries ranging from dual, 600 m long cables to a single receiver. Results show that short offset, low fold and very simple streamer positioning are sufficient to give a reliable 3D image of gas charged bodies. The 3D data allow a much more accurate risk delineation than 2D HR data. Moreover on financial grounds Mini-3D is comparable in cost to a classical HR 2D survey. In view of these results, such HR 3D should now be the standard for shallow gas surveying.

  14. 3D Synthetic Aperture PIV of a Freely Swimming Fish

    NASA Astrophysics Data System (ADS)

    Mendelson, Leah; Techet, Alexandra

    2012-11-01

    Fish owe much of their locomotive success to complex body geometries and wake interactions that cannot be fully characterized by planar experimental techniques including 2D PIV. Volumetric methods are valuable to illustrate and quantify these features, thus providing new insights for bioinspired design. In particular, synthetic aperture particle image velocimetry (SAPIV) uses light field imaging algorithms to reconstruct a 3D particle field which can then be analyzed using a 3D cross-correlation. Previous studies have shown that this technique is able to resolve all three velocity components on the same order length scale and to see around partial occlusions, such as a caudal fin, through the use of multiple cameras. To harness these capabilities for biomimetic use, SAPIV is used to depict the three-dimensional velocity field and vortical structures surrounding a freely swimming Giant danio (Devario aequipinnatus) during straight swims and turning maneuvers.

  15. High Resolution 3-D Waveform Tomography of the Lithospheric Structure of the Hellenic Subduction Zone

    NASA Astrophysics Data System (ADS)

    Lamara, Samir; Friederich, Wolfgang; Schumacher, Florian; Meier, Thomas; Egelados Working Group

    2015-04-01

    We present a high-resolution lithospheric shear-wave velocity model of the Hellenic subduction zone obtained by full waveform tomography of the EGELADOS project data. This high quality data was collected with the broadband amphibian seismic network EGELADOS that was deployed all over the southern Aegean from October 2005 to April 2007 providing a sampling of the south Aegean lithosphere with a resolution never reached before. Because of the strong deformations in the Hellenic subduction zone and the linear approximation in solving the full waveform inverse problem, a special care was taken to guarantee the best possible accuracy of earthquakes parameters and initial reference models. The accurate locations of the selected earthquakes were hence re-estimated and the best moment tensors were selected by computing the misfits between the observed seismograms for one event and a set of synthetics calculated for every value of the fault angles (strike, dip and rake) and hypocenter depths. On the other hand, instead of using an average 1D reference model for the complete region, a 1D path-specific approach permitted to obtain the 1D initial model for each source-receiver pair by waveform fitting using a grid search varying the Moho depth and the average S-wave velocity in the crust. These models were then refined by a 1D inversion and used to calculate the sensitivity kernels for each source-receiver pair. For the inversion, we adopted a special formulation including a correction term which permits to use the path-specific sensitivity kernels in an inversion for 3D velocity perturbations relative to a single 1D reference model constructed from all these 1D initial models. The inversion was done in frequency domain with a frequency window ranging from 0.03 Hz to 0.1 Hz. For the selected 2695 paths the total number of data values reached 140140. The model was discretized in volume cells with a varying vertical width and a fixed lateral one of approximately 15 km, resulting

  16. P- and S-wave Slowness Anomalies in the Mantle

    NASA Astrophysics Data System (ADS)

    Yao, Y.; Thorne, M. S.

    2015-12-01

    Anomalies in the slowness of teleseisms have been observed in numerous studies, with previous efforts focusing on crust and upper mantle sources for their origin. Little attention has been devoted to the global distribution of P- and S-wave slowness anomalies in the deep Earth. In this study, we use large aperture seismic array data to examine slowness anomalies as a function of depth in the lower mantle. We collected seismic recordings from all broadband seismic stations in North America for earthquakes between January 2004 and June 2015 with moment magnitudes between 5.8 and 7.5, event depths greater than 100 km, and epicentral distances from 40° to 90°. We chose the time range to coincide with the Earthscope seismic experiment. The epicentral distance range used in this study ensured the target phases, direct P and S wave arrivals, turned in the mantle at depths ranging from 1000 to 2800 km. The original data set contained 420 events with 171,696 seismograms. We inspected each seismogram manually and discarded traces without clear P or S arrivals. Our final data set consists of 278 events with 129,748 seismograms. For each event, we grouped the data into 3° radius geographic bins and calculated relative time shifts for each bin using the Automated and Interactive Measurement of Body-wave Arrival Times (AIMBAT) technique. AIMBAT is a python tool for measuring teleseismic arrival times based on the multi-channel cross-correlation (MCCC) method. For each bin, we plotted the relative time shifts as a function of epicentral distances and calculated the corresponding least-square regression line. The slowness (dT/dΔ) can be obtained as the slope of the regression line. The slowness values of all geographic bins were collected to build a slowness profile for each event. In order to identify slowness anomalies, these slowness profiles were compared with synthetic slowness profiles calculated using the 2.5-D axi-symmetric finite-difference methods PSVaxi for P waves

  17. Seismic characterization of fracture compliance in the field using P- and S-wave sources

    NASA Astrophysics Data System (ADS)

    Foord, Greg; Verdon, James P.; Kendall, J.-Michael

    2015-12-01

    Near-surface seismic field experiments using both P- and S-wave sources were carried out to image fractured limestones at two sites in southwest England. We measured P- and S-wave seismic velocities at multiple azimuths to aligned fracture sets, allowing us to determine the seismic anisotropy generated by these fractures. The effect of aligned fractures on seismic anisotropy is commonly modelled in terms of the additional compliance introduced by the fractures. Therefore, an understanding of fracture compliance is crucial both in terms of interpreting observations of anisotropy in the field and in forward modelling the effects of fractures on seismic wave propagation. Of particular concern is (1) the scaling of fracture compliance with fracture length scale, and (2) the controls on the ratio of normal to tangential compliance of the fractures (Ω = ZN/ZT). Our experimental design allows us to image both, and we find that Ω = 0.37 ± 0.06 and Ω = 0.75 ± 0.10 for our two study sites, while the absolute values of the tangential compliance range from 0.66 × 10-11 to 5.0 × 10-11 Pa-1 m.

  18. 3D MHD Models of Active Region Loops

    NASA Technical Reports Server (NTRS)

    Ofman, Leon

    2004-01-01

    Present imaging and spectroscopic observations of active region loops allow to determine many physical parameters of the coronal loops, such as the density, temperature, velocity of flows in loops, and the magnetic field. However, due to projection effects many of these parameters remain ambiguous. Three dimensional imaging in EUV by the STEREO spacecraft will help to resolve the projection ambiguities, and the observations could be used to setup 3D MHD models of active region loops to study the dynamics and stability of active regions. Here the results of 3D MHD models of active region loops are presented, and the progress towards more realistic 3D MHD models of active regions. In particular the effects of impulsive events on the excitation of active region loop oscillations, and the generation, propagations and reflection of EIT waves are shown. It is shown how 3D MHD models together with 3D EUV observations can be used as a diagnostic tool for active region loop physical parameters, and to advance the science of the sources of solar coronal activity.

  19. 3-D Technology Approaches for Biological Ecologies

    NASA Astrophysics Data System (ADS)

    Liu, Liyu; Austin, Robert; U. S-China Physical-Oncology Sciences Alliance (PS-OA) Team

    Constructing three dimensional (3-D) landscapes is an inevitable issue in deep study of biological ecologies, because in whatever scales in nature, all of the ecosystems are composed by complex 3-D environments and biological behaviors. Just imagine if a 3-D technology could help complex ecosystems be built easily and mimic in vivo microenvironment realistically with flexible environmental controls, it will be a fantastic and powerful thrust to assist researchers for explorations. For years, we have been utilizing and developing different technologies for constructing 3-D micro landscapes for biophysics studies in in vitro. Here, I will review our past efforts, including probing cancer cell invasiveness with 3-D silicon based Tepuis, constructing 3-D microenvironment for cell invasion and metastasis through polydimethylsiloxane (PDMS) soft lithography, as well as explorations of optimized stenting positions for coronary bifurcation disease with 3-D wax printing and the latest home designed 3-D bio-printer. Although 3-D technologies is currently considered not mature enough for arbitrary 3-D micro-ecological models with easy design and fabrication, I hope through my talk, the audiences will be able to sense its significance and predictable breakthroughs in the near future. This work was supported by the State Key Development Program for Basic Research of China (Grant No. 2013CB837200), the National Natural Science Foundation of China (Grant No. 11474345) and the Beijing Natural Science Foundation (Grant No. 7154221).

  20. 3D change detection - Approaches and applications

    NASA Astrophysics Data System (ADS)

    Qin, Rongjun; Tian, Jiaojiao; Reinartz, Peter

    2016-12-01

    Due to the unprecedented technology development of sensors, platforms and algorithms for 3D data acquisition and generation, 3D spaceborne, airborne and close-range data, in the form of image based, Light Detection and Ranging (LiDAR) based point clouds, Digital Elevation Models (DEM) and 3D city models, become more accessible than ever before. Change detection (CD) or time-series data analysis in 3D has gained great attention due to its capability of providing volumetric dynamics to facilitate more applications and provide more accurate results. The state-of-the-art CD reviews aim to provide a comprehensive synthesis and to simplify the taxonomy of the traditional remote sensing CD techniques, which mainly sit within the boundary of 2D image/spectrum analysis, largely ignoring the particularities of 3D aspects of the data. The inclusion of 3D data for change detection (termed 3D CD), not only provides a source with different modality for analysis, but also transcends the border of traditional top-view 2D pixel/object-based analysis to highly detailed, oblique view or voxel-based geometric analysis. This paper reviews the recent developments and applications of 3D CD using remote sensing and close-range data, in support of both academia and industry researchers who seek for solutions in detecting and analyzing 3D dynamics of various objects of interest. We first describe the general considerations of 3D CD problems in different processing stages and identify CD types based on the information used, being the geometric comparison and geometric-spectral analysis. We then summarize relevant works and practices in urban, environment, ecology and civil applications, etc. Given the broad spectrum of applications and different types of 3D data, we discuss important issues in 3D CD methods. Finally, we present concluding remarks in algorithmic aspects of 3D CD.

  1. RT3D tutorials for GMS users

    SciTech Connect

    Clement, T.P.; Jones, N.L.

    1998-02-01

    RT3D (Reactive Transport in 3-Dimensions) is a computer code that solves coupled partial differential equations that describe reactive-flow and transport of multiple mobile and/or immobile species in a three dimensional saturated porous media. RT3D was developed from the single-species transport code, MT3D (DoD-1.5, 1997 version). As with MT3D, RT3D also uses the USGS groundwater flow model MODFLOW for computing spatial and temporal variations in groundwater head distribution. This report presents a set of tutorial problems that are designed to illustrate how RT3D simulations can be performed within the Department of Defense Groundwater Modeling System (GMS). GMS serves as a pre- and post-processing interface for RT3D. GMS can be used to define all the input files needed by RT3D code, and later the code can be launched from within GMS and run as a separate application. Once the RT3D simulation is completed, the solution can be imported to GMS for graphical post-processing. RT3D v1.0 supports several reaction packages that can be used for simulating different types of reactive contaminants. Each of the tutorials, described below, provides training on a different RT3D reaction package. Each reaction package has different input requirements, and the tutorials are designed to describe these differences. Furthermore, the tutorials illustrate the various options available in GMS for graphical post-processing of RT3D results. Users are strongly encouraged to complete the tutorials before attempting to use RT3D and GMS on a routine basis.

  2. Transition zone S velocity structure beneath the East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Grand, S. P.; Brandt, M. B.

    2009-12-01

    Models of seismic velocity as a function of depth through the upper mantle provide some of the strongest constraints on the mineralogy and composition of the mantle. Although receiver function studies have provided new information on the depths of upper mantle discontinuities they do not provide as much information on seismic gradients and velocities in the upper mantle. The waveforms and travel times of upper mantle turning waves provide the strongest constraints on vertical variations in upper mantle velocity although in the past they suffered from the lack of dense profiles of data sampling a single part of the upper mantle that would minimize effects of 3D variations in velocity. Here we model a dense profile of triplicated upper mantle broadband S waves recorded by USArray and NARS-Baja stations in the western United States and Mexico. Earthquakes along the East Pacific Rise were recorded along profiles within 5 degree backazimuth windows with stations at a maximum of .5 degree separation. The distance range covered is from 30 to 60 degrees and thus the waves sample the mantle from the lithosphere to depths near 1000 km. The data were inverted using a conjugate gradient algorithm that utilizes the reflectivity synthetic technique. The results show a much smaller gradient within the transition zone than PREM with larger jumps in velocity at the 410 and 660 km depth discontinuities. These results are more consistent with velocities predicted for a pyrolite composition than the PREM model. Between pyrolite and piclogite, our results are far more consistent with velocities predicted for a pyrolite composition.

  3. The 2D and 3D hypersonic flows with unstructured meshes

    NASA Technical Reports Server (NTRS)

    Thareja, Rajiv

    1993-01-01

    Viewgraphs on 2D and 3D hypersonic flows with unstructured meshes are presented. Topics covered include: mesh generation, mesh refinement, shock-shock interaction, velocity contours, mesh movement, vehicle bottom surface, and adapted meshes.

  4. Feasibility of using P- and S-wave Attenuation for Monitoring of Bacterial Clogging in Unconsolidated Sediments

    NASA Astrophysics Data System (ADS)

    Noh, D. H.

    2015-12-01

    Accumulation of bacterial biopolymers in porous media is known to decrease permeability by several orders of magnitude, referred to as bioclogging, thereby altering the hydraulic flow systems of porous media. Successful microbial bioclogging treatments require geophysical monitoring techniques to provide appropriate spatial and temporal information on bacterial growth and activities in the subsurface; such monitoring datasets can be used to evaluate the status of plugged reservoir sections and optimize re-treatment if the plug degrades. This study investigated the variations of P- and S-wave attenuation of porous media for monitoring in-situ accumulation of bacterial biopolymers in sediments. Column experiments, where Leuconostoc mesenterorides were stimulated to produce the insoluble polysaccharide biopolymer (referred to as dextran) in a sand pack, were performed while monitoring changes in permeability as well as P- and S-wave responses. P-wave responses at ultrasonic and sub-ultrasonic frequency ranges (i.e., hundreds of kHz and tens of kHz) and S-wave responses at several kHz were acquired using ultrasonic transducers and bender elements during accumulation of the biopolymer. The permeability of the sand pack was reduced by more than one order of magnitude while the insoluble biopolymer, dextran, produced by Leuconostoc mesenteroides occupied ~10% pore volume. The amplitude of the P-wave signals decreased at the both ultrasonic (hundreds of kHz) and sub-ultrasonic (tens of kHz) frequency ranges; and the spectral ratio calculations confirmed an increase in P-wave attenuation (1/QP) in the both frequency ranges. The amplitude of the S-wave signals significantly increased during the increase in S-wave velocity, possibly due to the increased shear stiffness of the medium. However, the spectral ratio calculation suggested an increase in S-wave attenuation (1/QS) in the several kHz band. The observed changes in permeability and P- and S-wave attenuation were

  5. Seeing a Stellar Explosion in 3D

    NASA Astrophysics Data System (ADS)

    2010-08-01

    faster in some directions than others, leading to an irregular shape with some parts stretching out further into space. The first material to be ejected from the explosion travelled at an incredible 100 million km per hour, which is about a tenth of the speed of light or around 100 000 times faster than a passenger jet. Even at this breakneck speed it has taken 10 years to reach a previously existing ring of gas and dust puffed out from the dying star. The images also demonstrate that another wave of material is travelling ten times more slowly and is being heated by radioactive elements created in the explosion. "We have established the velocity distribution of the inner ejecta of Supernova 1987A," says lead author Karina Kjær. "Just how a supernova explodes is not very well understood, but the way the star exploded is imprinted on this inner material. We can see that this material was not ejected symmetrically in all directions, but rather seems to have had a preferred direction. Besides, this direction is different to what was expected from the position of the ring." Such asymmetric behaviour was predicted by some of the most recent computer models of supernovae, which found that large-scale instabilities take place during the explosion. The new observations are thus the first direct confirmation of such models. SINFONI is the leading instrument of its kind, and only the level of detail it affords allowed the team to draw their conclusions. Advanced adaptive optics systems counteracted the blurring effects of the Earth's atmosphere while a technique called integral field spectroscopy allowed the astronomers to study several parts of the supernova's chaotic core simultaneously, leading to the build-up of the 3D image. "Integral field spectroscopy is a special technique where for each pixel we get information about the nature and velocity of the gas," says Kjær. "This means that besides the normal picture we also have the velocity along the line of sight. Because we

  6. Mantle seismic structure beneath the MELT region of the east pacific rise from P and S wave tomography

    PubMed

    Toomey; Wilcock; Solomon; Hammond; Orcutt

    1998-05-22

    Relative travel time delays of teleseismic P and S waves, recorded during the Mantle Electromagnetic and Tomography (MELT) Experiment, have been inverted tomographically for upper-mantle structure beneath the southern East Pacific Rise. A broad zone of low seismic velocities extends beneath the rise to depths of about 200 kilometers and is centered to the west of the spreading center. The magnitudes of the P and S wave anomalies require the presence of retained mantle melt; the melt fraction near the rise exceeds the fraction 300 kilometers off axis by as little as 1%. Seismic anisotropy, induced by mantle flow, is evident in the P wave delays at near-vertical incidence and is consistent with a half-width of mantle upwelling of about 100 km.

  7. 3D measurement for rapid prototyping

    NASA Astrophysics Data System (ADS)

    Albrecht, Peter; Lilienblum, Tilo; Sommerkorn, Gerd; Michaelis, Bernd

    1996-08-01

    Optical 3-D measurement is an interesting approach for rapid prototyping. On one hand it's necessary to get the 3-D data of an object and on the other hand it's necessary to check the manufactured object (quality checking). Optical 3-D measurement can realize both. Classical 3-D measurement procedures based on photogrammetry cause systematic errors at strongly curved surfaces or steps in surfaces. One possibility to reduce these errors is to calculate the 3-D coordinates from several successively taken images. Thus it's possible to get higher spatial resolution and to reduce the systematic errors at 'problem surfaces.' Another possibility is to process the measurement values by neural networks. A modified associative memory smoothes and corrects the calculated 3-D coordinates using a-priori knowledge about the measurement object.

  8. Photorefractive Polymers for Updateable 3D Displays

    DTIC Science & Technology

    2010-02-24

    Final Performance Report 3. DATES COVERED (From - To) 01-01-2007 to 11-30-2009 4. TITLE AND SUBTITLE Photorefractive Polymers for Updateable 3D ...ABSTRACT During the tenure of this project a large area updateable 3D color display has been developed for the first time using a new co-polymer...photorefractive polymers have been demonstrated. Moreover, a 6 inch × 6 inch sample was fabricated demonstrating the feasibility of making large area 3D

  9. 3D Microperfusion Model of ADPKD

    DTIC Science & Technology

    2015-10-01

    Stratasys 3D printer . PDMS was cast in the negative molds in order to create permanent biocompatible plastic masters (SmoothCast 310). All goals of task...1 AWARD NUMBER: W81XWH-14-1-0304 TITLE: 3D Microperfusion Model of ADPKD PRINCIPAL INVESTIGATOR: David L. Kaplan CONTRACTING ORGANIZATION...ADDRESS. 1. REPORT DATE October 2015 2. REPORT TYPE Annual Report 3. DATES COVERED 15 Sep 2014 - 14 Sep 2015 4. TITLE AND SUBTITLE 3D

  10. 3D carotid plaque MR Imaging

    PubMed Central

    Parker, Dennis L.

    2015-01-01

    SYNOPSIS There has been significant progress made in 3D carotid plaque magnetic resonance imaging techniques in recent years. 3D plaque imaging clearly represents the future in clinical use. With effective flow suppression techniques, choices of different contrast weighting acquisitions, and time-efficient imaging approaches, 3D plaque imaging offers flexible imaging plane and view angle analysis, large coverage, multi-vascular beds capability, and even can be used in fast screening. PMID:26610656

  11. 3-D Extensions for Trustworthy Systems

    DTIC Science & Technology

    2011-01-01

    3- D Extensions for Trustworthy Systems (Invited Paper) Ted Huffmire∗, Timothy Levin∗, Cynthia Irvine∗, Ryan Kastner† and Timothy Sherwood...address these problems, we propose an approach to trustworthy system development based on 3- D integration, an emerging chip fabrication technique in...which two or more integrated circuit dies are fabricated individually and then combined into a single stack using vertical conductive posts. With 3- D

  12. Hardware Trust Implications of 3-D Integration

    DTIC Science & Technology

    2010-12-01

    enhancing a commod- ity processor with a variety of security functions. This paper examines the 3-D design approach and provides an analysis concluding...of key components. The question addressed by this paper is, “Can a 3-D control plane provide useful secure services when it is conjoined with an...untrust- worthy computation plane?” Design-level investigation of this question yields a definite yes. This paper explores 3- D applications and their

  13. Digital holography and 3-D imaging.

    PubMed

    Banerjee, Partha; Barbastathis, George; Kim, Myung; Kukhtarev, Nickolai

    2011-03-01

    This feature issue on Digital Holography and 3-D Imaging comprises 15 papers on digital holographic techniques and applications, computer-generated holography and encryption techniques, and 3-D display. It is hoped that future work in the area leads to innovative applications of digital holography and 3-D imaging to biology and sensing, and to the development of novel nonlinear dynamic digital holographic techniques.

  14. Dimensional accuracy of 3D printed vertebra

    NASA Astrophysics Data System (ADS)

    Ogden, Kent; Ordway, Nathaniel; Diallo, Dalanda; Tillapaugh-Fay, Gwen; Aslan, Can

    2014-03-01

    3D printer applications in the biomedical sciences and medical imaging are expanding and will have an increasing impact on the practice of medicine. Orthopedic and reconstructive surgery has been an obvious area for development of 3D printer applications as the segmentation of bony anatomy to generate printable models is relatively straightforward. There are important issues that should be addressed when using 3D printed models for applications that may affect patient care; in particular the dimensional accuracy of the printed parts needs to be high to avoid poor decisions being made prior to surgery or therapeutic procedures. In this work, the dimensional accuracy of 3D printed vertebral bodies derived from CT data for a cadaver spine is compared with direct measurements on the ex-vivo vertebra and with measurements made on the 3D rendered vertebra using commercial 3D image processing software. The vertebra was printed on a consumer grade 3D printer using an additive print process using PLA (polylactic acid) filament. Measurements were made for 15 different anatomic features of the vertebral body, including vertebral body height, endplate width and depth, pedicle height and width, and spinal canal width and depth, among others. It is shown that for the segmentation and printing process used, the results of measurements made on the 3D printed vertebral body are substantially the same as those produced by direct measurement on the vertebra and measurements made on the 3D rendered vertebra.

  15. s-Wave collisional frequency shift of a fermion clock.

    PubMed

    Hazlett, Eric L; Zhang, Yi; Stites, Ronald W; Gibble, Kurt; O'Hara, Kenneth M

    2013-04-19

    We report an s-wave collisional frequency shift of an atomic clock based on fermions. In contrast to bosons, the fermion clock shift is insensitive to the population difference of the clock states, set by the first pulse area in Ramsey spectroscopy, θ(1). The fermion shift instead depends strongly on the second pulse area θ(2). It allows the shift to be canceled, nominally at θ(2)=π/2, but correlations perturb the null to slightly larger θ(2). The frequency shift is relevant for optical lattice clocks and increases with the spatial inhomogeneity of the clock excitation field, naturally larger at optical frequencies.

  16. Electric-dipole allowed and intercombination transitions among the 3d 5, 3d 44s and 3d 44p levels of Fe IV

    NASA Astrophysics Data System (ADS)

    Deb, Narayan C.; Hibbert, Alan

    2010-07-01

    Oscillator strengths and transition rates for the electric-dipole (E1) allowed and intercombination transitions among 3d 5, 3d 44s and 3d 44p levels of Fe IV are calculated using the CIV3 code of Hibbert and coworkers. Using the Hartree-Fock functions up to 3d orbitals we have also optimized 4s, 4p, 4d, 4f, 5s, 5p and 5d orbitals of which 4s and 4p are taken to be spectroscopic and the remaining orbitals represent corrections to the spectroscopic orbitals or the correlation effects. The J-dependent levels of 108 LS states are included in the calculation and the relativistic effects are accounted for via the Breit-Pauli operator. Configurations are chosen in two steps: (a) two promotions were allowed from the 3p, 3d, 4s and 4p subshells, using all the orbitals; and (b) selective promotions from the 3s subshell are included, but only to the 3s and 4s orbitals. The ab initio fine-structure levels are then fine tuned to reproduce observed energy levels as closely as possible, and the resulting wavefunctions are used to calculate oscillator strengths and transition rates for all possible E1 transitions. For many of these transitions, the present results show good agreement between the length and velocity forms while for some transitions, some large disagreements are found with other available results. The complete list of weighted oscillator strengths, transition rates, and line strengths for transitions among the fine structure levels of the three lowest configurations are presented in ascending order of wavelength.

  17. FastScript3D - A Companion to Java 3D

    NASA Technical Reports Server (NTRS)

    Koenig, Patti

    2005-01-01

    FastScript3D is a computer program, written in the Java 3D(TM) programming language, that establishes an alternative language that helps users who lack expertise in Java 3D to use Java 3D for constructing three-dimensional (3D)-appearing graphics. The FastScript3D language provides a set of simple, intuitive, one-line text-string commands for creating, controlling, and animating 3D models. The first word in a string is the name of a command; the rest of the string contains the data arguments for the command. The commands can also be used as an aid to learning Java 3D. Developers can extend the language by adding custom text-string commands. The commands can define new 3D objects or load representations of 3D objects from files in formats compatible with such other software systems as X3D. The text strings can be easily integrated into other languages. FastScript3D facilitates communication between scripting languages [which enable programming of hyper-text markup language (HTML) documents to interact with users] and Java 3D. The FastScript3D language can be extended and customized on both the scripting side and the Java 3D side.

  18. 3D Simulations of the Beehive Proplyd

    NASA Astrophysics Data System (ADS)

    Feitosa, J. A.; Vasconcelos, M. J.; Cerqueira, A. H.

    2014-10-01

    Some star formation regions, like the Orion nebula, have stars of different masses, from massive stars, responsible for strong ionizing winds and HII regions, to low-mass stars, which spend a long time in the protostellar phase, and are frequently associated with protostellar disks and jets. Massive O or B stars emit a great deal of UV radiation, able to dissociate the hydrogen molecule (FUV radiation, energies between 6-13 eV), to ionize the atomic hydrogen (EUV radiation, energies greater than 13.6 eV) and heat the gas. Around these stars, a large and hot (10^{4}K) region is formed, known as HII region. T-Tauri stars inside HII regions produce a type of young stellar object, a proplyd, described with accuracy in O'Dell et al. (1993). Proplyds exhibit a cometary shape from which we can distinguish a central low-mass star with an accretion disk, an ionization front, a photodissociation region and, sometimes, an external bow shock and a protostellar jet. Its morphological characteristics depends on the distance between the low-mass star and the source of the ionizing radiation. The Beehive, a giant proplyd in Orion Nebula, has attracted attention due to its exotic system of rings coaxial to the HH540 jet's axis. Bally et al. (2005) suggested that the rings are perturbations due to the crossing of the ionization front by the jet. In this work, we test this hypothesis making 3D hydrodynamic numerical simulations over an adaptive grid, using the Yguazú-A code (Raga et al., 2000), properly adapted for the Beehive conditions. Our results show that the jet causes a perturbation in the ionization front of the proplyd, but is necessary to adjust carefully some parameters of the jet like its velocity and ejection frequency in order to have the results matching the observations.

  19. Constraining seismic velocity features combining short and long period signals: Test ground is Turkey

    NASA Astrophysics Data System (ADS)

    Bulut, Fatih; Eken, Tuna; Yolsal-Çevikbilen, Seda; Taymaz, Tuncay

    2015-04-01

    Verifying the seismic velocity models requires combining different techniques to obtain more reliable basement for further steps, e.g., earthquake location, moment tensor analysis etc. Especially, 2D/3D heterogeneities and velocity contrasts are the key unknowns to be addressed in order to achieve the best-possible setup for further analysis. In that frame, short and long period signals are combined to better constrain the unusual velocity features. Our approach employs P-wave particle motions and receiver functions to discriminate the velocity structure of different crustal blocks. P-wave particle motions are basically used to differentiate direction of incoming waves, which is an indirect measure of potential velocity contrast/heterogeneity in horizontal axis. In the meanwhile, P-wave receiver functions are used to estimate frequency dependent S-wave velocities at different crustal spots. Turkey, seismically the most active region in Europe, is selected to be the test ground for joint analysis scheme. The region has been continuously monitored by AFAD (Prime Ministry, Ankara) and Kandilli Observatory (Boğaziçi Üniversity, Istanbul). Furthermore, some particular regions have been densely monitored for a couple of years by temporary seismic networks, e.g., the IRIS network deployed in the frame of the North Anatolian Fault experiment. We integrated all available data to reach to the highest possible coverage for selected test sites. The results are jointly interpreted to refine existing crustal models in Turkey.

  20. 3D ultrafast ultrasound imaging in vivo.

    PubMed

    Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-10-07

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra--and inter-observer variability.

  1. 3D ultrafast ultrasound imaging in vivo

    NASA Astrophysics Data System (ADS)

    Provost, Jean; Papadacci, Clement; Esteban Arango, Juan; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-10-01

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra—and inter-observer variability.

  2. An aerial 3D printing test mission

    NASA Astrophysics Data System (ADS)

    Hirsch, Michael; McGuire, Thomas; Parsons, Michael; Leake, Skye; Straub, Jeremy

    2016-05-01

    This paper provides an overview of an aerial 3D printing technology, its development and its testing. This technology is potentially useful in its own right. In addition, this work advances the development of a related in-space 3D printing technology. A series of aerial 3D printing test missions, used to test the aerial printing technology, are discussed. Through completing these test missions, the design for an in-space 3D printer may be advanced. The current design for the in-space 3D printer involves focusing thermal energy to heat an extrusion head and allow for the extrusion of molten print material. Plastics can be used as well as composites including metal, allowing for the extrusion of conductive material. A variety of experiments will be used to test this initial 3D printer design. High altitude balloons will be used to test the effects of microgravity on 3D printing, as well as parabolic flight tests. Zero pressure balloons can be used to test the effect of long 3D printing missions subjected to low temperatures. Vacuum chambers will be used to test 3D printing in a vacuum environment. The results will be used to adapt a current prototype of an in-space 3D printer. Then, a small scale prototype can be sent into low-Earth orbit as a 3-U cube satellite. With the ability to 3D print in space demonstrated, future missions can launch production hardware through which the sustainability and durability of structures in space will be greatly improved.

  3. Prestack depth migration for 3D offshore methane hydrates data

    NASA Astrophysics Data System (ADS)

    Jang, Seonghyung; Kim, Tae-yeon

    2015-04-01

    One of the indicators for the existence of methane hydrates on seismic data is BSR (bottom simulated reflector), which shows the base of the gas hydrate stability zone. It shows a reversed phase polarity compared to that of the water bottom reflections and high amplitude reflections. It is well known acoustic velocity decrease at the contact between gas hydrates and free-gas-bearing sediments. Prestack reverse time migration (RTM) is a method for imaging the subsurface in depth domain using inner product of source wavefield extrapolation in forward and receiver wavefield extrapolation in backward. It is widely used for imaging the complex subsurface structures with keeping amplitude. We applied RTM to 3D offshore seismic data for methane hydrates exploration. The study area is 12 x 25 km with 120 survey lines offshore. The shot gathers were acquired with 2 streamers and each one has 240 channels. Shot and receiver spacing is 25 m and 12.5 m. The line spacing is 100 m. Near offset is 150 m and maximum far offset is 3137.5 m. The record length is 7 second with a sampling rate of 1 ms. Shot gathers after resampled with 4 ms were processed to enhance signal to noise ratio using conventional basic processing such as amplitude recovery, deconvolution, and band-pass filtering. Interval velocities which were calculated from conventional stack velocities were used for velocity model for RTM. The basic-processed shot gathers and a velocity model were used for input data to obtain 3D image using RTM. For RTM, 20 Hz Ricker wavelet were used and grid size of x, y and z direction is 20x20x20 m. The total number of shot gathers is 176,387 and every 10th shot gather was chosen for reducing computer times and storage. The result is 3D image with inline, cross-line and depth slice image. High amplitude events are shown around (6 km, 4 km, 2.3 km) of in-line image. Each depth slice shows amplitude variation according to different depth steps. Especially channel structure variation

  4. On the relative scattering of P- and S-waves

    NASA Technical Reports Server (NTRS)

    Malin, P. E.; Phinney, R. A.

    1985-01-01

    Using a single-scattering approximation, equations for the scattering attenuation coefficients of P-body and S-body waves are derived. The results are discussed in the light of the energy-renormalization approaches of Wu (1980, 1982) and Sato (1982) to seismic wave scattering. Practical methods for calculating the scattering attenuation coefficients for various earth models are emphasized. The conversions of P-waves to S-waves and S-waves to P-waves are included in the theory. The earth models are assumed to be randomly inhomogeneous, with their properties known only through their average-wavenumber power spectra. The power spectra are approximated with piecewise constant functions, each segment of which contributes to the net frequency-dependent scattering attenuation coefficient. The smallest and largest wavenumbers of a segment can be plotted along with the wavevectors of the incident and scattered waves on a wavenumber diagram. This diagram gives a geometric interpretation for the frequency behavior associated with each spectral segment, including a transition peak that is due entirely to the wavenumber limits of the segment. For regions of the earth where the inhomogeneity spectra are concentrated in a band of wavenumbers, it should be possible to observe such a peak in the apparent attenuation of seismic waves. Both the frequency and distance limits on the accuracy of the theoretical results are given.

  5. Fluctuations electrical conductivity in a granular s-wave superconductor

    NASA Astrophysics Data System (ADS)

    Salehi, H.; Yousefvand, A.; Zargar Shoushtari, M.

    2017-01-01

    The present study tries to evaluate the fluctuation electrical conductivity in a granular s-wave superconductor at the temperature near to the critical temperature. The evaluation is conducted under the condition of limited tunneling conductance between the grains and small impurity concentration. All the first order fluctuation corrections, involving the nonlocal scattered electron in a granular s-wave superconductor, are calculated in three dimensions and in the limit of clean. Using Green's function theory initially, the Cooperon (impurity vertex), λ (q , ε1 , ε2) , and the fluctuation propagator, Lk (q , Ωk) , are calculated in the presence of impurities. Then, the three distinct contributions of Aslamazov-Larkin, Maki-Thompson, and Density of states are calculated by means of the Kubo formula. Analysis shows that the terms of Aslamazov-Larkin and anomalous Maki-Thompson have positive contributions to the conductivity in the clean limit, whereas the terms of Density of state and the regular Maki-Thompson have negative signs, leading to the reduction of total fluctuation conductivity.

  6. Integration of real-time 3D image acquisition and multiview 3D display

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaoxing; Geng, Zheng; Li, Tuotuo; Li, Wei; Wang, Jingyi; Liu, Yongchun

    2014-03-01

    Seamless integration of 3D acquisition and 3D display systems offers enhanced experience in 3D visualization of the real world objects or scenes. The vivid representation of captured 3D objects displayed on a glasses-free 3D display screen could bring the realistic viewing experience to viewers as if they are viewing real-world scene. Although the technologies in 3D acquisition and 3D display have advanced rapidly in recent years, effort is lacking in studying the seamless integration of these two different aspects of 3D technologies. In this paper, we describe our recent progress on integrating a light-field 3D acquisition system and an autostereoscopic multiview 3D display for real-time light field capture and display. This paper focuses on both the architecture design and the implementation of the hardware and the software of this integrated 3D system. A prototype of the integrated 3D system is built to demonstrate the real-time 3D acquisition and 3D display capability of our proposed system.

  7. Immersive 3D Geovisualization in Higher Education

    ERIC Educational Resources Information Center

    Philips, Andrea; Walz, Ariane; Bergner, Andreas; Graeff, Thomas; Heistermann, Maik; Kienzler, Sarah; Korup, Oliver; Lipp, Torsten; Schwanghart, Wolfgang; Zeilinger, Gerold

    2015-01-01

    In this study, we investigate how immersive 3D geovisualization can be used in higher education. Based on MacEachren and Kraak's geovisualization cube, we examine the usage of immersive 3D geovisualization and its usefulness in a research-based learning module on flood risk, called GEOSimulator. Results of a survey among participating students…

  8. A 3D Geostatistical Mapping Tool

    SciTech Connect

    Weiss, W. W.; Stevenson, Graig; Patel, Ketan; Wang, Jun

    1999-02-09

    This software provides accurate 3D reservoir modeling tools and high quality 3D graphics for PC platforms enabling engineers and geologists to better comprehend reservoirs and consequently improve their decisions. The mapping algorithms are fractals, kriging, sequential guassian simulation, and three nearest neighbor methods.

  9. 3D Printing. What's the Harm?

    ERIC Educational Resources Information Center

    Love, Tyler S.; Roy, Ken

    2016-01-01

    Health concerns from 3D printing were first documented by Stephens, Azimi, Orch, and Ramos (2013), who found that commercially available 3D printers were producing hazardous levels of ultrafine particles (UFPs) and volatile organic compounds (VOCs) when plastic materials were melted through the extruder. UFPs are particles less than 100 nanometers…

  10. Topology dictionary for 3D video understanding.

    PubMed

    Tung, Tony; Matsuyama, Takashi

    2012-08-01

    This paper presents a novel approach that achieves 3D video understanding. 3D video consists of a stream of 3D models of subjects in motion. The acquisition of long sequences requires large storage space (2 GB for 1 min). Moreover, it is tedious to browse data sets and extract meaningful information. We propose the topology dictionary to encode and describe 3D video content. The model consists of a topology-based shape descriptor dictionary which can be generated from either extracted patterns or training sequences. The model relies on 1) topology description and classification using Reeb graphs, and 2) a Markov motion graph to represent topology change states. We show that the use of Reeb graphs as the high-level topology descriptor is relevant. It allows the dictionary to automatically model complex sequences, whereas other strategies would require prior knowledge on the shape and topology of the captured subjects. Our approach serves to encode 3D video sequences, and can be applied for content-based description and summarization of 3D video sequences. Furthermore, topology class labeling during a learning process enables the system to perform content-based event recognition. Experiments were carried out on various 3D videos. We showcase an application for 3D video progressive summarization using the topology dictionary.

  11. 3D elastic control for mobile devices.

    PubMed

    Hachet, Martin; Pouderoux, Joachim; Guitton, Pascal

    2008-01-01

    To increase the input space of mobile devices, the authors developed a proof-of-concept 3D elastic controller that easily adapts to mobile devices. This embedded device improves the completion of high-level interaction tasks such as visualization of large documents and navigation in 3D environments. It also opens new directions for tomorrow's mobile applications.

  12. 3D Printing of Molecular Models

    ERIC Educational Resources Information Center

    Gardner, Adam; Olson, Arthur

    2016-01-01

    Physical molecular models have played a valuable role in our understanding of the invisible nano-scale world. We discuss 3D printing and its use in producing models of the molecules of life. Complex biomolecular models, produced from 3D printed parts, can demonstrate characteristics of molecular structure and function, such as viral self-assembly,…

  13. 3D Printed Block Copolymer Nanostructures

    ERIC Educational Resources Information Center

    Scalfani, Vincent F.; Turner, C. Heath; Rupar, Paul A.; Jenkins, Alexander H.; Bara, Jason E.

    2015-01-01

    The emergence of 3D printing has dramatically advanced the availability of tangible molecular and extended solid models. Interestingly, there are few nanostructure models available both commercially and through other do-it-yourself approaches such as 3D printing. This is unfortunate given the importance of nanotechnology in science today. In this…

  14. Infrastructure for 3D Imaging Test Bed

    DTIC Science & Technology

    2007-05-11

    analysis. (c.) Real time detection & analysis of human gait: using a video camera we capture walking human silhouette for pattern modeling and gait ... analysis . Fig. 5 shows the scanning result result that is fed into a Geo-magic software tool for 3D meshing. Fig. 5: 3D scanning result In

  15. Wow! 3D Content Awakens the Classroom

    ERIC Educational Resources Information Center

    Gordon, Dan

    2010-01-01

    From her first encounter with stereoscopic 3D technology designed for classroom instruction, Megan Timme, principal at Hamilton Park Pacesetter Magnet School in Dallas, sensed it could be transformative. Last spring, when she began pilot-testing 3D content in her third-, fourth- and fifth-grade classrooms, Timme wasn't disappointed. Students…

  16. Stereo 3-D Vision in Teaching Physics

    ERIC Educational Resources Information Center

    Zabunov, Svetoslav

    2012-01-01

    Stereo 3-D vision is a technology used to present images on a flat surface (screen, paper, etc.) and at the same time to create the notion of three-dimensional spatial perception of the viewed scene. A great number of physical processes are much better understood when viewed in stereo 3-D vision compared to standard flat 2-D presentation. The…

  17. Pathways for Learning from 3D Technology

    ERIC Educational Resources Information Center

    Carrier, L. Mark; Rab, Saira S.; Rosen, Larry D.; Vasquez, Ludivina; Cheever, Nancy A.

    2012-01-01

    The purpose of this study was to find out if 3D stereoscopic presentation of information in a movie format changes a viewer's experience of the movie content. Four possible pathways from 3D presentation to memory and learning were considered: a direct connection based on cognitive neuroscience research; a connection through "immersion"…

  18. 3D, or Not to Be?

    ERIC Educational Resources Information Center

    Norbury, Keith

    2012-01-01

    It may be too soon for students to be showing up for class with popcorn and gummy bears, but technology similar to that behind the 3D blockbuster movie "Avatar" is slowly finding its way into college classrooms. 3D classroom projectors are taking students on fantastic voyages inside the human body, to the ruins of ancient Greece--even to faraway…

  19. Static & Dynamic Response of 3D Solids

    SciTech Connect

    Lin, Jerry

    1996-07-15

    NIKE3D is a large deformations 3D finite element code used to obtain the resulting displacements and stresses from multi-body static and dynamic structural thermo-mechanics problems with sliding interfaces. Many nonlinear and temperature dependent constitutive models are available.

  20. The applicability of 3D Doppler tomography to studies of polars