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Sample records for time-lapse seismic velocity

  1. Full waveform inversion of repeating seismic events to estimate time-lapse velocity changes

    Science.gov (United States)

    Kamei, R.; Lumley, D.

    2017-05-01

    Seismic monitoring provides valuable information regarding the time-varying changes in subsurface physical properties caused by natural or man-made processes. However, the resulting changes in the earth's subsurface properties are often small both in terms of magnitude and spatial extent, leading to minimal time-lapse differences in seismic amplitude or traveltime. In order to better extract information from the time-lapse data, we show that exploiting the full seismic waveform information can be critical. In this study, we develop and test methods of full waveform inversion that estimate an optimal subsurface model of time-varying elastic properties in order to fit the observed time-lapse seismic data with predicted waveforms based on numerical solutions of the wave equation. Time-lapse full waveform inversion is nonlinear and non-unique, and depends on the knowledge of the baseline velocity model before a change, and (non-)repeatability of earthquake source and sensor parameters, and of ambient and cultural noise. We propose to use repeating earthquake data sets acquired with permanent arrays of seismic sensors to enhance the repeatability of source and sensor parameters. We further develop and test time-lapse parallel, double-difference and bootstrapping inversion strategies to mitigate the dependence on the baseline velocity model. The parallel approach uses a time-invariant full waveform inversion method to estimate velocity models independently of the different source event times. The double-difference approach directly estimates velocity changes from time-lapse waveform differences, requiring excellent repeatability. The bootstrapping approach inverts for velocity models sequentially in time, implicitly constraining the time-lapse inversions, while relaxing an explicit requirement for high data repeatability. We assume that prior to the time-lapse inversion, we can estimate the true source locations and the origin time of the events, and also we can also

  2. Time-lapse seismic within reservoir engineering

    NARCIS (Netherlands)

    Oldenziel, T.

    2003-01-01

    Time-lapse 3D seismic is a fairly new technology allowing dynamic reservoir characterisation in a true volumetric sense. By investigating the differences between multiple seismic surveys, valuable information about changes in the oil/gas reservoir state can be captured. Its interpretation involves

  3. The state of the art in time-lapse seismic monitoring of heavy oil fields

    Energy Technology Data Exchange (ETDEWEB)

    Lines, Larry; Embleton, Joan [Chorus (Canada)

    2011-07-01

    Reservoir characterization is an essential tool for the maximization of heavy oil production. Characterization allows the changes occurring in the reservoir during production to be monitored. The current study demonstrates that time-lapse 3D seismology may be used to monitor these changes over time. When a reservoir change influences seismic velocity, changes in the subsurface may be assessed by time-lapse 3D seismology. Multiple factors (such as seismic noise, near-surface seasonal variations, or consistent acquisition and processing) affect the data acquired when using time-lapse 3D seismology to monitor heavy oil fields. The study shows how to circumvent these factors to obtain consistent and usable data. Using information such as well logs, Vp/Vs ratios from core samples and seismic data, it was demonstrated that time-lapse 3D seismology is a suitable characterization method for reservoir changes in heavy oil production.

  4. Super-resolution Time-Lapse Seismic Waveform Inversion

    Science.gov (United States)

    Ovcharenko, O.; Kazei, V.; Peter, D. B.; Alkhalifah, T.

    2017-12-01

    Time-lapse seismic waveform inversion is a technique, which allows tracking changes in the reservoirs over time. Such monitoring is relatively computationally extensive and therefore it is barely feasible to perform it on-the-fly. Most of the expenses are related to numerous FWI iterations at high temporal frequencies, which is inevitable since the low-frequency components can not resolve fine scale features of a velocity model. Inverted velocity changes are also blurred when there is noise in the data, so the problem of low-resolution images is widely known. One of the problems intensively tackled by computer vision research community is the recovering of high-resolution images having their low-resolution versions. Usage of artificial neural networks to reach super-resolution from a single downsampled image is one of the leading solutions for this problem. Each pixel of the upscaled image is affected by all the pixels of its low-resolution version, which enables the workflow to recover features that are likely to occur in the corresponding environment. In the present work, we adopt machine learning image enhancement technique to improve the resolution of time-lapse full-waveform inversion. We first invert the baseline model with conventional FWI. Then we run a few iterations of FWI on a set of the monitoring data to find desired model changes. These changes are blurred and we enhance their resolution by using a deep neural network. The network is trained to map low-resolution model updates predicted by FWI into the real perturbations of the baseline model. For supervised training of the network we generate a set of random perturbations in the baseline model and perform FWI on the noisy data from the perturbed models. We test the approach on a realistic perturbation of Marmousi II model and demonstrate that it outperforms conventional convolution-based deblurring techniques.

  5. 2D Time-lapse Seismic Tomography Using An Active Time Constraint (ATC) Approach

    Science.gov (United States)

    We propose a 2D seismic time-lapse inversion approach to image the evolution of seismic velocities over time and space. The forward modeling is based on solving the eikonal equation using a second-order fast marching method. The wave-paths are represented by Fresnel volumes rathe...

  6. Time-lapse seismic waveform modelling and attribute analysis using hydromechanical models for a deep reservoir undergoing depletion

    Science.gov (United States)

    He, Y.-X.; Angus, D. A.; Blanchard, T. D.; Wang, G.-L.; Yuan, S.-Y.; Garcia, A.

    2016-04-01

    Extraction of fluids from subsurface reservoirs induces changes in pore pressure, leading not only to geomechanical changes, but also perturbations in seismic velocities and hence observable seismic attributes. Time-lapse seismic analysis can be used to estimate changes in subsurface hydromechanical properties and thus act as a monitoring tool for geological reservoirs. The ability to observe and quantify changes in fluid, stress and strain using seismic techniques has important implications for monitoring risk not only for petroleum applications but also for geological storage of CO2 and nuclear waste scenarios. In this paper, we integrate hydromechanical simulation results with rock physics models and full-waveform seismic modelling to assess time-lapse seismic attribute resolution for dynamic reservoir characterization and hydromechanical model calibration. The time-lapse seismic simulations use a dynamic elastic reservoir model based on a North Sea deep reservoir undergoing large pressure changes. The time-lapse seismic traveltime shifts and time strains calculated from the modelled and processed synthetic data sets (i.e. pre-stack and post-stack data) are in a reasonable agreement with the true earth models, indicating the feasibility of using 1-D strain rock physics transform and time-lapse seismic processing methodology. Estimated vertical traveltime shifts for the overburden and the majority of the reservoir are within ±1 ms of the true earth model values, indicating that the time-lapse technique is sufficiently accurate for predicting overburden velocity changes and hence geomechanical effects. Characterization of deeper structure below the overburden becomes less accurate, where more advanced time-lapse seismic processing and migration is needed to handle the complex geometry and strong lateral induced velocity changes. Nevertheless, both migrated full-offset pre-stack and near-offset post-stack data image the general features of both the overburden and

  7. Seismic imaging of reservoir flow properties: Time-lapse amplitude changes

    Energy Technology Data Exchange (ETDEWEB)

    Vasco, D.W.; Datta-Gupta, Akhil; Behrens, Ron; Condon, Pat; Rickett, Jame s

    2003-03-13

    Asymptotic methods provide an efficient means by which to infer reservoir flow properties, such as permeability, from time-lapse seismic data. A trajectory-based methodology, much like ray-based methods for medical and seismic imaging, is the basis for an iterative inversion of time-lapse amplitude changes. In this approach a single reservoir simulation is required for each iteration of the algorithm. A comparison between purely numerical and the trajectory-based sensitivities demonstrates their accuracy. An application to a set of synthetic amplitude changes indicates that they can recover large-scale reservoir permeability variations from time-lapse data. In an application of actual time-lapse amplitude changes from the Bay Marchand field in the Gulf of Mexico we are able to reduce the misfit by 81% in twelve iterations. The time-lapse observations indicate lower permeabilities are required in the central portion of the reservoir.

  8. Discrimination between phase and amplitude attributes in time-lapse seismic streamer data

    NARCIS (Netherlands)

    Spetzler, J.; Kvam, O.

    2006-01-01

    Time-lapse seismic experiments aim to obtain information about production-related effects in hydrocarbon reservoirs to increase the recovery percentage. However, nonrepeatability problems such as acquisition differences, overburden effects, and noise are often significantly stronger than the imprint

  9. Seismic imaging of reservoir flow properties: Time-lapse pressurechanges

    Energy Technology Data Exchange (ETDEWEB)

    Vasco, Don W.

    2003-04-08

    Time-lapse fluid pressure and saturation estimates are sensitive to reservoir flow properties such as permeability. In fact, given time-lapse estimates of pressure and saturation changes, one may define a linear partial differential equation for permeability variations within the reservoir. The resulting linear inverse problem can be solved quite efficiently using sparse matrix techniques. An application to a set of crosswell saturation and pressure estimates from a CO{sub 2} flood at the Lost Hills field in California demonstrates the utility of this approach. From the crosswell estimates detailed estimates of reservoir permeability are produced. The resulting permeability estimates agree with a permeability log in an adjacent well and are in accordance with water and CO{sub 2} saturation changes in the interwell region.

  10. Time-lapse seismic attribute analysis for a water-flooded reservoir

    International Nuclear Information System (INIS)

    Jin, Long; Sen, M K; Stoffa, P L; Seif, R K

    2008-01-01

    One of the goals of time-lapse seismic monitoring is the direct detection of the fluid front and two-phase contact area. However, several factors affect the quality of time-lapse seismic difference data and decrease detectability. One of these factors is random noise. In this paper, we propose five different methods aimed at improving the quality and detectability of noisy time-lapse seismic difference data. Common to these methods is the transform of the differences to a domain where the time-lapse signal and random noise are well separated. Our proposed methods include direct Fourier transform based spectral decomposition, bispectra, wavelet transform, singular value decomposition and hybrid methods. We also propose a method that combines multiple time-lapse difference data and gives a final difference which enhances the common part and attenuates the differences of the multiple difference images resulting in a better detectability than the original images. A synthetic time-lapse model is used to demonstrate the feasibility of our proposed methods

  11. Time-lapse high-resolution seismic surveys in the Mississippi Delta mudflow area, offshore Louisiana

    Energy Technology Data Exchange (ETDEWEB)

    Son-Hindmarsh, R.; Hughson, R.A.; Ploessel, M.R.

    1984-05-01

    Time-lapse high-resolution surveys are useful for studying rapidly changing geologic features such as the mudflows of the Mississippi Delta, and for assessing how these potentially hazardous features might affect offshore structures. For time-lapse surveys, an initial high-resolution seismic survey is repeated at specified time intervals, following the same grid of tracklines, using the same seismic systems and a precise navigation system. Time-lapse surveys have been used successfully to monitor the active mudflow about 6 miles upslope from Shell Offshore Inc.'s Cognac Platform. The surveys show that mudflow activity has had no effect on the Platform. Time-lapse surveys obtain the most accurate determination of seafloor changes available at the present time. If one compares two or more random surveys in an area, instead of carefully performed time-lapse surveys, the accuracy of the results may be less than the actural amount of change; so results may be meaningless or misleading. Time-lapse surveys can produce results with vertical accuracy of about + or 5 feet along survey tracklines.

  12. Time-lapse seismic imaging of the Reykjanes geothermal reservoir

    NARCIS (Netherlands)

    Weemstra, C.; Obermann, Anne; Blanck, Hanna; Verdel, Arie; Paap, B; Guðnason, Egill Árni; Hersir, Gylfi Páll; Jousset, Philippe; Sigurðsson, Ömar

    2016-01-01

    We report on the results obtained from a dense seismic deployment over a geothermal reservoir. The reservoir has been producing continuously for almost a decade and is located on the tip of the Reykjanes peninsula, SW Iceland. The seismic stations on top of the reservoir have continuously recorded

  13. Time-lapse seismic - repeatability versus usefulness and 2D versus 3D

    Science.gov (United States)

    Landro, M.

    2017-12-01

    Time-lapse seismic has developed rapidly over the past decades, especially for monitoring of oil and gas reservoirs and subsurface storage of CO2. I will review and discuss some of the critical enabling factors for the commercial success of this technology. It was early realized that how well we are able to repeat our seismic experiment is crucial. However, it is always a question of detectability versus repeatability. For marine seismic, there are several factors limiting the repeatability: Weather conditions, positioning of sources and receivers and so on. I will discuss recent improvements in both acquisition and processing methods over the last decade. It is well known that repeated 3D seismic data is the most accurate tool for reservoir monitoring purposes. However, several examples show that 2D seismic data may be used for monitoring purposes despite lower repeatability. I will use examples from an underground blow out in the North Sea, and repeated 2D seismic lines acquired before and after the Tohoku earthquake in 2011 to illustrate this. A major challenge when using repeated 2D seismic for subsurface monitoring purposes is the lack of 3D calibration points and significantly less amount of data. For marine seismic acquisition, feathering issues and crossline dip effects become more critical compared to 3D seismic acquisition. Furthermore, the uncertainties arising from a non-ideal 2D seismic acquisition are hard to assess, since the 3D subsurface geometry has not been mapped. One way to shed more light on this challenge is to use 3D time lapse seismic modeling testing various crossline dips or geometries. Other ways are to use alternative data sources, such as bathymetry, time lapse gravity or electromagnetic data. The end result for all time-lapse monitoring projects is an interpretation associated with uncertainties, and for the 2D case these uncertainties are often large. The purpose of this talk is to discuss how to reduces and control these

  14. Oil Sands Characteristics and Time-Lapse and P-SV Seismic Steam Monitoring, Athabasca, Canada

    Science.gov (United States)

    Takahashi, A.; Nakayama, T.; Kashihara, K.; Skinner, L.; Kato, A.

    2008-12-01

    -injection. The differences of the seismic responses between the time-lapse seismic volumes can be quantitatively explained by P-wave velocity decrease of the oil sands layers due to steam-injection. In addition, the data suggests that a larger area would be influenced by pressure than temperature. We calculate several seismic attributes such as RMS values of amplitude difference, maximum cross correlations, and interval velocity differences. These attributes are integrated by using self-organization maps (SOM) and K-means methods. By this analysis, we are able to distinguish areas of steam chamber growth from transitional and non-affected areas. In addition, 3D P-SV converted-wave processing and analysis are applied on the second 3D data set (recorded with three-component digital sensor). Low Vp/Vs values in the P-SV volume show areas of steam chamber development, and high Vp/Vs values indicate transitional zones. Our analysis of both time-lapse 3D seismic and 3D P-SV data along with the rock physics model can be used to monitor qualitatively and quantitatively the rock property changes of the inter-well reservoir sands in the field.

  15. Latest time-lapse seismic data from Sleipner yield new insights into CO2 plume development

    NARCIS (Netherlands)

    Chadwick, R.A.; Noy, D.; Arts, R.; Eiken, O.

    2009-01-01

    Since its inception in 1996, the CO2 injection operation at Sleipner has been monitored by 3D time-lapse seismic surveys. Striking images of the CO2 plume have been obtained, showing a multi-tier feature of high reflectivity, interpreted as arising from a number of thin layers of CO2 trapped beneath

  16. Marine time-Lapse (4D) Seismic Operations and Improved Imaging

    International Nuclear Information System (INIS)

    Taylor, N.

    2002-01-01

    Time-lapse (4D) seismic monitoring of producing reservoirs presents strong potential for improving reservoir management. Case studies show the capacity of 4D seismic to monitor injected fluid fronts, locate bypassed oil, map pressure compartmentalization, and delineate the sealing or leaking flow properties of faults. The advent of 4D seismic is expected to have as significant effect on increased recovery as the earlier introduction of 3D seismic in the late 80's 4D seismic has now become an established part of operators long-term plans for subsurface assets and in recent years much of the seismic activity in the North Sea has been the acquisition of 4D seismic surveys.The producing reservoir will usually feature a floating or fixed surface installation. As these installations obstruct towed streamer operations a second vessel is often required to undershoot the obstruction, Fugro-Geoteam's fleet of 2D and 3D seismic vessels is ideally suited to this type of operation and the company has gained valuable operational experience in the North Sea, Mediterranean and the Middle East.Errors in the positioning of in-sea equipment impact seismic imaging. These errors are compounded with each successive time-lapse survey. Fugro continually strives for ways to meet customers' expectations for improved performance. Therefore, in 2001 Fugro introduced a new high accuracy positioning service. This paper focuses on Fugro-Geoteam's 4D/undershoot operational experience and the new positioning 'High Performance' service

  17. Time-Lapse Monitoring of Subsurface Fluid Flow using Parsimonious Seismic Interferometry

    KAUST Repository

    Hanafy, Sherif

    2017-04-21

    A typical small-scale seismic survey (such as 240 shot gathers) takes at least 16 working hours to be completed, which is a major obstacle in case of time-lapse monitoring experiments. This is especially true if the subject that needs to be monitored is rapidly changing. In this work, we will discuss how to decrease the recording time from 16 working hours to less than one hour of recording. Here, the virtual data has the same accuracy as the conventional data. We validate the efficacy of parsimonious seismic interferometry with the time-lapse mentoring idea with field examples, where we were able to record 30 different data sets within a 2-hour period. The recorded data are then processed to generate 30 snapshots that shows the spread of water from the ground surface down to a few meters.

  18. Time-lapse seismic analysis of the North Sea Fulmar Field

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, David H.; McKenny, Robert S.; Burkhart, Tucker D.

    1998-12-31

    Time-lapse seismic analysis has been applied to two 3-D seismic surveys acquired over the central North Sea Fulmar field in a pre-production survey shot in 1977, reprocessed in 1987, and a survey in 1992. The Upper Jurassic reservoirs in the field have been under production since 1982. Differences in averaged impedance between the 1977 and 1992 surveys clearly show the effects of water influx and pressure decline. The changes observed in the seismic data are overall consistent with predictions obtained from a full-field, history-matched simulation. Differences in details may suggest areas of bypassed oil. Dta quality is not sufficient to serve as the sole basis for drilling decisions. 1 ref., 6 figs.

  19. Active and passive electrical and seismic time-lapse monitoring of earthen embankments

    Science.gov (United States)

    Rittgers, Justin Bradley

    In this dissertation, I present research involving the application of active and passive geophysical data collection, data assimilation, and inverse modeling for the purpose of earthen embankment infrastructure assessment. Throughout the dissertation, I identify several data characteristics, and several challenges intrinsic to characterization and imaging of earthen embankments and anomalous seepage phenomena, from both a static and time-lapse geophysical monitoring perspective. I begin with the presentation of a field study conducted on a seeping earthen dam, involving static and independent inversions of active tomography data sets, and self-potential modeling of fluid flow within a confined aquifer. Additionally, I present results of active and passive time-lapse geophysical monitoring conducted during two meso-scale laboratory experiments involving the failure and self-healing of embankment filter materials via induced vertical cracking. Identified data signatures and trends, as well as 4D inversion results, are discussed as an underlying motivation for conducting subsequent research. Next, I present a new 4D acoustic emissions source localization algorithm that is applied to passive seismic monitoring data collected during a full-scale embankment failure test. Acoustic emissions localization results are then used to help spatially constrain 4D inversion of collocated self-potential monitoring data. I then turn to time-lapse joint inversion of active tomographic data sets applied to the characterization and monitoring of earthen embankments. Here, I develop a new technique for applying spatiotemporally varying structural joint inversion constraints. The new technique, referred to as Automatic Joint Constraints (AJC), is first demonstrated on a synthetic 2D joint model space, and is then applied to real geophysical monitoring data sets collected during a full-scale earthen embankment piping-failure test. Finally, I discuss some non-technical issues related to

  20. Carbon Dioxide Sequestration Site Characterization and Time-lapse Monitoring Using Reflection Seismic Methods

    Science.gov (United States)

    Alshuhail, Abdullah A.

    2011-12-01

    Of the various disciplines involved in carbon capture and storage, seismic methods are critically important. In this dissertation, two case studies in west-central Alberta were investigated by employing reflection seismic methods, rock physics and numerical modelling. In the first case study, regional and local seismic site characterization was undertaken as part of the Wabamun Area CO2 Sequestration Project. The results show that P-wave reflection seismology can be an effective tool in regional and local mapping of the continuity of the carbonate Nisku aquifer as well as in delineating geologic discontinuities, such as karsting, that may compromise storage integrity. Furthermore, the information provided by the seismic data was valuable when integrated with petrophysical data in order to reduce the ambiguity in identifying CO 2 injection "sweet spots". Results from the fluid substitution and numerical forward seismic modelling suggest that CO2 anomalies in stiff carbonate aquifers like the Nisku Formation are small and so is the change in seismic response. For instance, the maximum change in reflection time and NRMS amplitude in time-lapse P-wave reflection surface seismic data was found to be ˜ 1.5 ms and ˜ 24%, respectively. Detection of these small changes depends on a number of factors, including data repeatability, frequency bandwidth and CO2 saturation scheme. The change in the S-wave properties is much smaller than in the acoustic properties suggesting that it is unlikely that PS-wave would be successful in identifying CO 2 anomaly. The second case study pertains to 4-D seismic monitoring at the Pembina-Cardium CO2 Pilot Project site where multi-component surface seismic and walk-away vertical seismic profile methods were implemented as part of the monitoring program. The quality of these data, in particular, was compromised by interference caused by infrastructure development which resulted in the loss of ˜ 20% of the seismic shot locations. The 4-D

  1. A multimethod Global Sensitivity Analysis to aid the calibration of geomechanical models via time-lapse seismic data

    Science.gov (United States)

    Price, D. C.; Angus, D. A.; Garcia, A.; Fisher, Q. J.; Parsons, S.; Kato, J.

    2018-03-01

    Time-lapse seismic attributes are used extensively in the history matching of production simulator models. However, although proven to contain information regarding production induced stress change, it is typically only loosely (i.e. qualitatively) used to calibrate geomechanical models. In this study we conduct a multimethod Global Sensitivity Analysis (GSA) to assess the feasibility and aid the quantitative calibration of geomechanical models via near-offset time-lapse seismic data. Specifically, the calibration of mechanical properties of the overburden. Via the GSA, we analyse the near-offset overburden seismic traveltimes from over 4000 perturbations of a Finite Element (FE) geomechanical model of a typical High Pressure High Temperature (HPHT) reservoir in the North Sea. We find that, out of an initially large set of material properties, the near-offset overburden traveltimes are primarily affected by Young's modulus and the effective stress (i.e. Biot) coefficient. The unexpected significance of the Biot coefficient highlights the importance of modelling fluid flow and pore pressure outside of the reservoir. The FE model is complex and highly nonlinear. Multiple combinations of model parameters can yield equally possible model realizations. Consequently, numerical calibration via a large number of random model perturbations is unfeasible. However, the significant differences in traveltime results suggest that more sophisticated calibration methods could potentially be feasible for finding numerous suitable solutions. The results of the time-varying GSA demonstrate how acquiring multiple vintages of time-lapse seismic data can be advantageous. However, they also suggest that significant overburden near-offset seismic time-shifts, useful for model calibration, may take up to 3 yrs after the start of production to manifest. Due to the nonlinearity of the model behaviour, similar uncertainty in the reservoir mechanical properties appears to influence overburden

  2. Time-Lapse Monitoring with 4D Seismic Coda Waves in Active, Passive and Ambient Noise Data

    Science.gov (United States)

    Lumley, D. E.; Kamei, R.; Saygin, E.; Shragge, J. C.

    2017-12-01

    The Earth's subsurface is continuously changing, due to temporal variations in fluid flow, stress, temperature, geomechanics and geochemistry, for example. These physical changes occur at broad tectonic and earthquake scales, and also at very detailed near-surface and reservoir scales. Changes in the physical states of the earth cause time-varying changes in the physical properties of rocks and fluids, which can be monitored with natural or manmade seismic waves. Time-lapse (4D) seismic monitoring is important for applications related to natural and induced seismicity, hydrocarbon and groundwater reservoir depletion, CO2 sequestration etc. An exciting new research area involves moving beyond traditional methods in order to use the full complex time-lapse scattered wavefield (4D coda waves) for both manmade active-source 3D/4D seismic data, and also to use continuous recordings of natural-source passive seismic data, especially (micro) earthquakes and ocean ambient noise. This research involves full wave-equation approaches including waveform inversion (FWI), interferometry, Large N sensor arrays, "big data" information theory, and high performance supercomputing (HPC). I will present high-level concepts and recent data results that are quite spectacular and highly encouraging.

  3. Seismic time-lapse imaging using Interferometric least-squares migration

    KAUST Repository

    Sinha, Mrinal

    2016-09-06

    One of the problems with 4D surveys is that the environmental conditions change over time so that the experiment is insufficiently repeatable. To mitigate this problem, we propose the use of interferometric least-squares migration (ILSM) to estimate the migration image for the baseline and monitor surveys. Here, a known reflector is used as the reference reflector for ILSM. Results with synthetic and field data show that ILSM can eliminate artifacts caused by non-repeatability in time-lapse surveys.

  4. A Dynamic Programming Model for Optimizing Frequency of Time-Lapse Seismic Monitoring in Geological CO2 Storage

    Science.gov (United States)

    Bhattacharjya, D.; Mukerji, T.; Mascarenhas, O.; Weyant, J.

    2005-12-01

    Designing a cost-effective and reliable monitoring program is crucial to the success of any geological CO2 storage project. Effective design entails determining both, the optimal measurement modality, as well as the frequency of monitoring the site. Time-lapse seismic provides the best spatial coverage and resolution for reservoir monitoring. Initial results from Sleipner (Norway) have demonstrated effective monitoring of CO2 plume movement. However, time-lapse seismic is an expensive monitoring technique especially over the long term life of a storage project and should be used judiciously. We present a mathematical model based on dynamic programming that can be used to estimate site-specific optimal frequency of time-lapse surveys. The dynamics of the CO2 sequestration process are simplified and modeled as a four state Markov process with transition probabilities. The states are M: injected CO2 safely migrating within the target zone; L: leakage from the target zone to the adjacent geosphere; R: safe migration after recovery from leakage state; and S: seepage from geosphere to the biosphere. The states are observed only when a monitoring survey is performed. We assume that the system may go to state S only from state L. We also assume that once observed to be in state L, remedial measures are always taken to bring it back to state R. Remediation benefits are captured by calculating the expected penalty if CO2 seeped into the biosphere. There is a trade-off between the conflicting objectives of minimum discounted costs of performing the next time-lapse survey and minimum risk of seepage and its associated costly consequences. A survey performed earlier would spot the leakage earlier. Remediation methods would have been utilized earlier, resulting in savings in costs attributed to excessive seepage. On the other hand, there are also costs for the survey and remedial measures. The problem is solved numerically using Bellman's optimality principal of dynamic

  5. Interpretaion of synthetic seismic time-lapse monitoring data for Korea CCS project based on the acoustic-elastic coupled inversion

    Science.gov (United States)

    Oh, J.; Min, D.; Kim, W.; Huh, C.; Kang, S.

    2012-12-01

    Recently, the CCS (Carbon Capture and Storage) is one of the promising methods to reduce the CO2 emission. To evaluate the success of the CCS project, various geophysical monitoring techniques have been applied. Among them, the time-lapse seismic monitoring is one of the effective methods to investigate the migration of CO2 plume. To monitor the injected CO2 plume accurately, it is needed to interpret seismic monitoring data using not only the imaging technique but also the full waveform inversion, because subsurface material properties can be estimated through the inversion. However, previous works for interpreting seismic monitoring data are mainly based on the imaging technique. In this study, we perform the frequency-domain full waveform inversion for synthetic data obtained by the acoustic-elastic coupled modeling for the geological model made after Ulleung Basin, which is one of the CO2 storage prospects in Korea. We suppose the injection layer is located in fault-related anticlines in the Dolgorae Deformed Belt and, for more realistic situation, we contaminate the synthetic monitoring data with random noise and outliers. We perform the time-lapse full waveform inversion in two scenarios. One scenario is that the injected CO2 plume migrates within the injection layer and is stably captured. The other scenario is that the injected CO2 plume leaks through the weak part of the cap rock. Using the inverted P- and S-wave velocities and Poisson's ratio, we were able to detect the migration of the injected CO2 plume. Acknowledgment This work was financially supported by the Brain Korea 21 project of Energy Systems Engineering, the "Development of Technology for CO2 Marine Geological Storage" program funded by the Ministry of Land, Transport and Maritime Affairs (MLTM) of Korea and the Korea CCS R&D Center (KCRC) grant funded by the Korea government (Ministry of Education, Science and Technology) (No. 2012-0008926).

  6. A Sparse Bayesian Imaging Technique for Efficient Recovery of Reservoir Channels With Time-Lapse Seismic Measurements

    KAUST Repository

    Sana, Furrukh

    2016-06-01

    Subsurface reservoir flow channels are characterized by high-permeability values and serve as preferred pathways for fluid propagation. Accurate estimation of their geophysical structures is thus of great importance for the oil industry. The ensemble Kalman filter (EnKF) is a widely used statistical technique for estimating subsurface reservoir model parameters. However, accurate reconstruction of the subsurface geological features with the EnKF is challenging because of the limited measurements available from the wells and the smoothing effects imposed by the \\\\ell _{2} -norm nature of its update step. A new EnKF scheme based on sparse domain representation was introduced by Sana et al. (2015) to incorporate useful prior structural information in the estimation process for efficient recovery of subsurface channels. In this paper, we extend this work in two ways: 1) investigate the effects of incorporating time-lapse seismic data on the channel reconstruction; and 2) explore a Bayesian sparse reconstruction algorithm with the potential ability to reduce the computational requirements. Numerical results suggest that the performance of the new sparse Bayesian based EnKF scheme is enhanced with the availability of seismic measurements, leading to further improvement in the recovery of flow channels structures. The sparse Bayesian approach further provides a computationally efficient framework for enforcing a sparse solution, especially with the possibility of using high sparsity rates through the inclusion of seismic data.

  7. Ensemble-based reservoir characterization using time-lapse seismic waveform data

    NARCIS (Netherlands)

    Leeuwenburgh, O.; Brouwer, J.; Trani, M.

    2010-01-01

    Assisted history matching methods are beginning to offer the possibility to use 4D seismic data in quantitative ways for reservoir characterization. We use the waveform data without any explicit inversion or interpretation step directly in an ensemble-based assisted history matching scheme with a 3D

  8. Synthetic versus real time-lapse seismic data at the Sleipner CO2 injection site

    NARCIS (Netherlands)

    Arts, R.J.; Chadwick, R.A.; Eiken, O.; Trani, M.; Dortland, S.

    2007-01-01

    CO2 has been injected into the Utsira Sand at Sleipner since 1996, with more than 9 million tonnes currently in the reservoir. Seismic monitoring surveys to follow the migration of the CO2 in the reservoir have been carried out in 1999, 2001, 2002, 2004 and 2006. The CO2 plume is imaged on the

  9. Application of Time-Lapse Seismic Monitoring for the Control and Optimization of CO2 Enhanced Oil Recovery Operations

    Energy Technology Data Exchange (ETDEWEB)

    Brian Toelle

    2008-11-30

    This project, 'Application of Time-Lapse Seismic Monitoring for the Control and Optimization of CO{sub 2} Enhanced Oil Recovery Operations', investigated the potential for monitoring CO{sub 2} floods in carbonate reservoirs through the use of standard p-wave seismic data. This primarily involved the use of 4D seismic (time lapse seismic) in an attempt to observe and map the movement of the injected CO{sub 2} through a carbonate reservoir. The differences between certain seismic attributes, such as amplitude, were used for this purpose. This technique has recently been shown to be effective in CO{sub 2} monitoring in Enhanced Oil Recovery (EOR) projects, such as Weyborne. This study was conducted in the Charlton 30/31 field in the northern Michigan Basin, which is a Silurian pinnacle reef that completed its primary production in 1997 and was scheduled for enhanced oil recovery using injected CO{sub 2}. Prior to injection an initial 'Base' 3D survey was obtained over the field and was then processed and interpreted. CO{sub 2} injection within the main portion of the reef was conducted intermittently during 13 months starting in August 2005. During this time, 29,000 tons of CO{sub 2} was injected into the Guelph formation, historically known as the Niagaran Brown formation. By September 2006, the reservoir pressure within the reef had risen to approximately 2000 lbs and oil and water production from the one producing well within the field had increased significantly. The determination of the reservoir's porosity distribution, a critical aspect of reservoir characterization and simulation, proved to be a significant portion of this project. In order to relate the differences observed between the seismic attributes seen on the multiple 3D seismic surveys and the actual location of the CO{sub 2}, a predictive reservoir simulation model was developed based on seismic attributes obtained from the base 3D seismic survey and available well data. This

  10. Quantitative monitoring of CO2 injection at Sleipner using seismic full waveform inversion in the time lapse mode and rock physics modeling

    International Nuclear Information System (INIS)

    Queisser, M.P.

    2012-01-01

    Carbon capture and sequestration is a technology to achieve a considerable deceleration of CO 2 emission promptly. Since 1996 one of the largest CO 2 storage projects is taking place at Sleipner in the Norwegian North Sea. In order to monitor injected CO 2 , time lapse seismic monitoring surveys have been carried out. Estimating subsurface parameters from the Sleipner seismic data is a challenging problem due to the specific geology of the storage reservoir, which is further complicated by injected CO 2 . Most seismic imaging methods enable only qualitative insights into the subsurface. Motivated by the need for a quantitative seismic monitoring of the injected CO 2 , I have applied 2D seismic full waveform inversion to seismic data sets from Sleipner from 1994 (baseline), 1999 and 2006 along three seismic lines to infer subsurface parameters and parameter changes in the storage reservoir. The P-wave velocity is the major parameter, as it is the most sensitive to CO 2 injection. An energy preconditioning of the gradient has been implemented. The usual source wavelet calibration did not prove to be reliable. An alternative source calibration has been successfully applied. By comparing seismic images with inversion results, I found that using seismic images to locate CO 2 accumulations in the subsurface may be misleading. The quantitative imaging approach using full waveform inversion resulted in a consistent evolution of the model parameter with time. Major reductions in P-wave velocity and hence the CO 2 accumulations could be quantitatively imaged down to a resolution of 10 m. Observed travel time shifts due to CO 2 injection are comparable to those derived from the inversion result. In order to estimate CO 2 saturations, rock physical concepts have been combined and extended to arrive at a rock physical formulation of the subsurface at Sleipner. I used pseudo Monte Carlo rock physics modeling to assess the influence of lithologic heterogeneity on the CO 2

  11. Time-lapse imaging of fault properties at seismogenic depth using repeating earthquakes, active sources and seismic ambient noise

    Science.gov (United States)

    Cheng, Xin

    2009-12-01

    The time-varying stress field of fault systems at seismogenic depths plays the mort important role in controlling the sequencing and nucleation of seismic events. Using seismic observations from repeating earthquakes, controlled active sources and seismic ambient noise, five studies at four different fault systems across North America, Central Japan, North and mid-West China are presented to describe our efforts to measure such time dependent structural properties. Repeating and similar earthquakes are hunted and analyzed to study the post-seismic fault relaxation at the aftershock zone of the 1984 M 6.8 western Nagano and the 1976 M 7.8 Tangshan earthquakes. The lack of observed repeating earthquakes at western Nagano is attributed to the absence of a well developed weak fault zone, suggesting that the fault damage zone has been almost completely healed. In contrast, the high percentage of similar and repeating events found at Tangshan suggest the existence of mature fault zones characterized by stable creep under steady tectonic loading. At the Parkfield region of the San Andreas Fault, repeating earthquake clusters and chemical explosions are used to construct a scatterer migration image based on the observation of systematic temporal variations in the seismic waveforms across the occurrence time of the 2004 M 6 Parkfield earthquake. Coseismic fluid charge or discharge in fractures caused by the Parkfield earthquake is used to explain the observed seismic scattering properties change at depth. In the same region, a controlled source cross-well experiment conducted at SAFOD pilot and main holes documents two large excursions in the travel time required for a shear wave to travel through the rock along a fixed pathway shortly before two rupture events, suggesting that they may be related to pre-rupture stress induced changes in crack properties. At central China, a tomographic inversion based on the theory of seismic ambient noise and coda wave interferometry

  12. Modeling of time-lapse multi-scale seismic monitoring of CO2 injected into a fault zone to enhance the characterization of permeability in enhanced geothermal systems

    Science.gov (United States)

    Zhang, R.; Borgia, A.; Daley, T. M.; Oldenburg, C. M.; Jung, Y.; Lee, K. J.; Doughty, C.; Altundas, B.; Chugunov, N.; Ramakrishnan, T. S.

    2017-12-01

    Subsurface permeable faults and fracture networks play a critical role for enhanced geothermal systems (EGS) by providing conduits for fluid flow. Characterization of the permeable flow paths before and after stimulation is necessary to evaluate and optimize energy extraction. To provide insight into the feasibility of using CO2 as a contrast agent to enhance fault characterization by seismic methods, we model seismic monitoring of supercritical CO2 (scCO2) injected into a fault. During the CO2 injection, the original brine is replaced by scCO2, which leads to variations in geophysical properties of the formation. To explore the technical feasibility of the approach, we present modeling results for different time-lapse seismic methods including surface seismic, vertical seismic profiling (VSP), and a cross-well survey. We simulate the injection and production of CO2 into a normal fault in a system based on the Brady's geothermal field and model pressure and saturation variations in the fault zone using TOUGH2-ECO2N. The simulation results provide changing fluid properties during the injection, such as saturation and salinity changes, which allow us to estimate corresponding changes in seismic properties of the fault and the formation. We model the response of the system to active seismic monitoring in time-lapse mode using an anisotropic finite difference method with modifications for fracture compliance. Results to date show that even narrow fault and fracture zones filled with CO2 can be better detected using the VSP and cross-well survey geometry, while it would be difficult to image the CO2 plume by using surface seismic methods.

  13. Mobility Effect on Poroelastic Seismic Signatures in Partially Saturated Rocks With Applications in Time-Lapse Monitoring of a Heavy Oil Reservoir

    Science.gov (United States)

    Zhao, Luanxiao; Yuan, Hemin; Yang, Jingkang; Han, De-hua; Geng, Jianhua; Zhou, Rui; Li, Hui; Yao, Qiuliang

    2017-11-01

    Conventional seismic analysis in partially saturated rocks normally lays emphasis on estimating pore fluid content and saturation, typically ignoring the effect of mobility, which decides the ability of fluids moving in the porous rocks. Deformation resulting from a seismic wave in heterogeneous partially saturated media can cause pore fluid pressure relaxation at mesoscopic scale, thereby making the fluid mobility inherently associated with poroelastic reflectivity. For two typical gas-brine reservoir models, with the given rock and fluid properties, the numerical analysis suggests that variations of patchy fluid saturation, fluid compressibility contrast, and acoustic stiffness of rock frame collectively affect the seismic reflection dependence on mobility. In particular, the realistic compressibility contrast of fluid patches in shallow and deep reservoir environments plays an important role in determining the reflection sensitivity to mobility. We also use a time-lapse seismic data set from a Steam-Assisted Gravity Drainage producing heavy oil reservoir to demonstrate that mobility change coupled with patchy saturation possibly leads to seismic spectral energy shifting from the baseline to monitor line. Our workflow starts from performing seismic spectral analysis on the targeted reflectivity interface. Then, on the basis of mesoscopic fluid pressure diffusion between patches of steam and heavy oil, poroelastic reflectivity modeling is conducted to understand the shift of the central frequency toward low frequencies after the steam injection. The presented results open the possibility of monitoring mobility change of a partially saturated geological formation from dissipation-related seismic attributes.

  14. Time-lapse Seismic Refraction Monitoring of an Active Landslide in Lias Group Mudrocks, North Yorkshire, UK

    Science.gov (United States)

    Uhlemann, S.; Whiteley, J.; Chambers, J. E.; Inauen, C.; Swift, R. T.

    2017-12-01

    Geophysical monitoring of the internal moisture content and processes of landslides is an increasingly common approach to the characterisation and assessment of the hydrogeological condition of rainfall-triggered landslides. Geoelectrical monitoring methods are sensitive to changes in the subsurface moisture conditions that cause the failure of unstable slopes, typically through the increase of pore water pressures and softening of materials within the landslide system. The application of seismic methods to the monitoring of landslides has not been as extensively applied as geoelectrical approaches, but the seismic method can determine elastic properties of landslide materials that can characterise and identify changes in the geomechanical condition of landslide systems that also lead to slope failure. We present the results of a seismic refraction monitoring campaign undertaken at the Hollin Hill Landslide Observatory in North Yorkshire, UK. This campaign has involved the repeat acquisition of surface acquired high resolution P- and S-wave seismic refraction data. The monitoring profile traverses a 142m long section from the crest to the toe of an active landslide comprising of mudstone and sandstone. Data were acquired at six to nine week intervals between October 2016 and October 2017. This repeat acquisition approach allowed for the imaging of seismically determined property changes of the landslide throughout the annual climatic cycle. Initial results showed that changes in the moisture dynamics of the landslide are reflected by changes in the seismic character of the inverted tomograms. Changes in the seismic properties are linked to the changes in the annual climatic cycle, particularly in relation to effective rainfall. The results indicate that the incorporation of seismic monitoring data into ongoing geoelectrical monitoring programmes can provide complementary geomechanical data to enhance our understanding of the internal condition of landslide systems

  15. A-3 Construction Time Lapse

    Science.gov (United States)

    2009-01-01

    A time lapse from start to finish of steel erection for the 235-foot tall A-3 Test Stand. Ground work for the stand was broken in August 2008 and the final structural steel beam was placed April 9, 2009.

  16. Seismic texture and amplitude analysis of large scale fluid escape pipes using time lapses seismic surveys: examples from the Loyal Field (Scotland, UK)

    Science.gov (United States)

    Maestrelli, Daniele; Jihad, Ali; Iacopini, David; Bond, Clare

    2016-04-01

    Fluid escape pipes are key features of primary interest for the analysis of vertical fluid flow and secondary hydrocarbon migration in sedimentary basin. Identified worldwide (Løset et al., 2009), they acquired more and more importance as they represent critical pathways for supply of methane and potential structure for leakage into the storage reservoir (Cartwright & Santamarina, 2015). Therefore, understanding their genesis, internal characteristics and seismic expression, is of great significance for the exploration industry. Here we propose a detailed characterization of the internal seismic texture of some seal bypass system (e.g fluid escape pipes) from a 4D seismic survey (released by the BP) recently acquired in the Loyal Field. The seal by pass structure are characterized by big-scale fluid escape pipes affecting the Upper Paleogene/Neogene stratigraphic succession in the Loyal Field, Scotland (UK). The Loyal field, is located on the edge of the Faroe-Shetland Channel slope, about 130 km west of Shetland (Quadrants 204/205 of the UKCS) and has been recently re-appraised and re developed by a consortium led by BP. The 3D detailed mapping analysis of the full and partial stack survey (processed using amplitude preservation workflows) shows a complex system of fluid pipe structure rooted in the pre Lista formation and developed across the paleogene and Neogene Units. Geometrical analysis show that pipes got diameter varying between 100-300 m and a length of 500 m to 2 km. Most pipes seem to terminate abruptly at discrete subsurface horizons or in diffuse termination suggesting multiple overpressured events and lateral fluid migration (through Darcy flows) across the overburden units. The internal texture analysis of the large pipes, (across both the root and main conduit zones), using near, medium and far offset stack dataset (processed through an amplitude preserved PSTM workflow) shows a tendency of up-bending of reflection (rather than pulls up artefacts

  17. Time-lapse joint AVO inversion using generalized linear method based on exact Zoeppritz equations

    Science.gov (United States)

    Zhi, Longxiao; Gu, Hanming

    2018-03-01

    The conventional method of time-lapse AVO (Amplitude Versus Offset) inversion is mainly based on the approximate expression of Zoeppritz equations. Though the approximate expression is concise and convenient to use, it has certain limitations. For example, its application condition is that the difference of elastic parameters between the upper medium and lower medium is little and the incident angle is small. In addition, the inversion of density is not stable. Therefore, we develop the method of time-lapse joint AVO inversion based on exact Zoeppritz equations. In this method, we apply exact Zoeppritz equations to calculate the reflection coefficient of PP wave. And in the construction of objective function for inversion, we use Taylor series expansion to linearize the inversion problem. Through the joint AVO inversion of seismic data in baseline survey and monitor survey, we can obtain the P-wave velocity, S-wave velocity, density in baseline survey and their time-lapse changes simultaneously. We can also estimate the oil saturation change according to inversion results. Compared with the time-lapse difference inversion, the joint inversion doesn't need certain assumptions and can estimate more parameters simultaneously. It has a better applicability. Meanwhile, by using the generalized linear method, the inversion is easily implemented and its calculation cost is small. We use the theoretical model to generate synthetic seismic records to test and analyze the influence of random noise. The results can prove the availability and anti-noise-interference ability of our method. We also apply the inversion to actual field data and prove the feasibility of our method in actual situation.

  18. History matching of time-lapse crosswell data using ensemble kalman filtering

    KAUST Repository

    de Matos Ravanelli, Fabio Miguel

    2015-09-03

    Data from crosswell seismic surveys is processed to provide crosswell time-lapse data to map fluid changes in a reservoir where time-lapse or 4D seismic data is unavailable or unreliable, such as in onshore reservoirs. The resultant processing results provide quantitative information for history matching purposes using a probabilistic approach to take in account uncertainties in the geological model and reduce uncertainties in reservoir production forecasts.

  19. Extraction of layer-specific seismic velocity in a porous medium through seismic interferometry applied to ultrasonic measurements of CO2 sequestration

    NARCIS (Netherlands)

    Draganov, D.S.; Ghose, R.; Heller, H.K.J.

    2016-01-01

    Purpose: Time-lapse seismic monitoring constitutes the foundation for most monitoring programmes involving CO2 storage. When using time-lapse seismics, two major sources of uncertainty in the estimation of changes in the reservoir properties, like saturation and pressure, are the non-repeatability

  20. Application of a linear finite-frequency theory to time-lapse crosswell tomography in ultrasonic and numerical experiments

    NARCIS (Netherlands)

    Spetzler, J.; Sijacic, D.; Wolf, K.H.A.A.

    2007-01-01

    Time-lapse seismic monitoring is the geophysical discipline whereby multiple data sets recorded at the same location but at different times are used to locate and quantify temporal changes in the elastic parameters of the subsurface. We validate a time-lapse monitoring method by crosswell tomography

  1. Project Sedan: Seismic Velocity Study

    National Research Council Canada - National Science Library

    Warner, S. E

    1962-01-01

    .... detonations by measuring seismic wave travel times. Because of the superiority of the system time resolution as compared with conventional geophysical exploration equipment, improved accuracy was anticipated as well as an opportunity to dry-run...

  2. Interferometric full-waveform inversion of time-lapse data

    KAUST Repository

    Sinha, Mrinal

    2017-08-17

    One of the key challenges associated with time-lapse surveys is ensuring the repeatability between the baseline and monitor surveys. Non-repeatability between the surveys is caused by varying environmental conditions over the course of different surveys. To overcome this challenge, we propose the use of interferometric full waveform inversion (IFWI) for inverting the velocity model from data recorded by baseline and monitor surveys. A known reflector is used as the reference reflector for IFWI, and the data are naturally redatumed to this reference reflector using natural reflections as the redatuming operator. This natural redatuming mitigates the artifacts introduced by the repeatability errors that originate above the reference reflector.

  3. Time-Lapse Measurement of Wellbore Integrity

    Science.gov (United States)

    Duguid, A.

    2017-12-01

    Well integrity is becoming more important as wells are used longer or repurposed. For CO2, shale gas, and other projects it has become apparent that wells represent the most likely unintended migration pathway for fluids out of the reservoir. Comprehensive logging programs have been employed to determine the condition of legacy wells in North America. These studies provide examples of assessment technologies. Logging programs have included pulsed neutron logging, ultrasonic well mapping, and cement bond logging. While these studies provide examples of what can be measured, they have only conducted a single round of logging and cannot show if the well has changed over time. Recent experience with time-lapse logging of three monitoring wells at a US Department of Energy sponsored CO2 project has shown the full value of similar tools. Time-lapse logging has shown that well integrity changes over time can be identified. It has also shown that the inclusion of and location of monitoring technologies in the well and the choice of construction materials must be carefully considered. Two of the wells were approximately eight years old at the time of study; they were constructed with steel and fiberglass casing sections and had lines on the outside of the casing running to the surface. The third well was 68 years old when it was studied and was originally constructed as a production well. Repeat logs were collected six or eight years after initial logging. Time-lapse logging showed the evolution of the wells. The results identified locations where cement degraded over time and locations that showed little change. The ultrasonic well maps show clearly that the lines used to connect the monitoring technology to the surface are visible and have a local effect on cement isolation. Testing and sampling was conducted along with logging. It provided insight into changes identified in the time-lapse log results. Point permeability testing was used to provide an in-situ point

  4. Time-lapse photogrammetry in geomorphic studies

    Science.gov (United States)

    Eltner, Anette; Kaiser, Andreas

    2017-04-01

    Image based approaches to reconstruct the earth surface (Structure from Motion - SfM) are establishing as a standard technology for high resolution topographic data. This is amongst other advantages due to the comparatively ease of use and flexibility of data generation. Furthermore, the increased spatial resolution led to its implementation at a vast range of applications from sub-mm to tens-of-km scale. Almost fully automatic calculation of referenced digital elevation models allows for a significant increase of temporal resolution, as well, potentially up to sub-second scales. Thereby, the setup of a time-lapse multi-camera system is necessary and different aspects need to be considered: The camera array has to be temporary stable or potential movements need to be compensated by temporary stable reference targets/areas. The stability of the internal camera geometry has to be considered due to a usually significantly lower amount of images of the scene, and thus redundancy for parameter estimation, compared to more common SfM applications. Depending on the speed of surface change, synchronisation has to be very accurate. Due to the usual application in the field, changing environmental conditions important for lighting and visual range are also crucial factors to keep in mind. Besides these important considerations much potential is comprised by time-lapse photogrammetry. The integration of multi-sensor systems, e.g. using thermal cameras, enables the potential detection of other processes not visible with RGB-images solely. Furthermore, the implementation of low-cost sensors allows for a significant increase of areal coverage and their setup at locations, where a loss of the system cannot be ruled out. The usage of micro-computers offers smart camera triggering, e.g. acquiring images with increased frequency controlled by a rainfall-triggered sensor. In addition these micro-computers can enable on-site data processing, e.g. recognition of increased surface

  5. Estimation of pore pressure from seismic velocities

    International Nuclear Information System (INIS)

    Perez, Zayra; Ojeda, German Y; Mateus, Darwin

    2009-01-01

    On pore pressure calculations it is common to obtain a profile in a well bore, which is then extrapolated toward offset wells. This practice might generate mistakes on pore pressure measurements, since geological conditions may change from a well bore to another, even into the same basin. Therefore, it is important to use other tools which allow engineers not only to detect and estimate in an indirect way overpressure zones, but also to keep a lateral tracking of possible changes that may affect those values in the different formations. Taking into account this situation, we applied a methodology that estimates formation pressure from 3D seismic velocities by using the Eaton method. First, we estimated formation pore pressure; then, we identified possible overpressure zones. Finally, those results obtained from seismic information were analyzed involving well logs and pore pressure tests, in order to compare real data with prediction based on seismic information from the Colombian foothill.

  6. Effect of Phase Transformations on Seismic Velocities

    Science.gov (United States)

    Weidner, D. J.; Li, L.; Whitaker, M.; Triplett, R.

    2017-12-01

    The radial velocity structure of the Earth consists of smooth variations of velocities with depth punctuated by abrupt changes of velocity, which are typically due to multivariant phase transformations, where high - low pressure phases can coexist. In this mixed phase region, both the effective shear and bulk moduli will be significantly reduced by the dynamic interaction of the propagating wave and the phase transition if the period of the wave is long enough relative to the kinetic time so that some of the transition can take place. In this presentation, we will give examples from both laboratory studies of phases transitions of Earth minerals and the calculated velocity profile based on our models. We focus on understanding the time limiting factor of the phase transformation in order to extrapolate laboratory results to Earth observations. Both the olivine to ringwoodite transition and KLB-1 partial melting are explored. We find that when the transformation requires diffusion, the kinetics are often slowed down considerably and as a result the diffusivity of atoms become the limiting factor of characteristic time. Specifically Fe-Mg exchange rate in the olivine-ringwoodite phase transition becomes the limiting factor that seismic waves are likely to sample. On the other hand, partial melting is an extremely fast phase transformation at seismic wave periods. We present evidence that ultrasonic waves, with a period of a few tens of nanoseconds, are slowed by the reduction of the effective elastic moduli in this case.

  7. Seismic Wave Velocity in Earth's Shallow Core

    Science.gov (United States)

    Alexandrakis, C.; Eaton, D. W.

    2008-12-01

    Studies of the outer core indicate that it is composed of liquid Fe and Ni alloyed with a ~10% fraction of light elements such as O, S or Si. Recently, unusual features, such as sediment accumulation, immiscible fluid layers or stagnant convection, have been predicted in the shallow core region. Secular cooling and compositional buoyancy drive vigorous convection that sustains the geodynamo, although critical details of light-element composition and thermal regime remain uncertain. Seismic velocity models can provide important constraints on the light element composition, however global reference models, such as Preliminary Reference Earth Model (PREM), IASP91 and AK135 vary significantly in the 200 km below the core-mantle boundary. Past studies of the outermost core velocity structure have been hampered by traveltime uncertainties due to lowermost mantle heterogeneities. The recently published Empirical Transfer Function (ETF) method has been shown to reduce the uncertainty using a waveform stacking approach to improve global observations of SmKS teleseismic waves. Here, we apply the ETF method to achieve a precise top-of-core velocity measurement of 8.05 ± 0.03 km/s. This new model accords well with PREM. Since PREM is based on the adiabatic form of the Adams-Williamson equation, it assumes a well mixed (i.e. homogeneous) composition. This result suggests a lack of heterogeneity in the outermost core due to layering or stagnant convection.

  8. Assessing ground compaction via time lapse surface wave analysis

    Czech Academy of Sciences Publication Activity Database

    Dal Moro, Giancarlo; Al-Arifi, N.; Moustafa, S.S.R.

    2016-01-01

    Roč. 13, č. 3 (2016), s. 249-256 ISSN 1214-9705 Institutional support: RVO:67985891 Keywords : Full velocity spectrum (FVS) analysis * ground compaction * ground compaction * phase velocities * Rayleigh waves * seismic data inversion * surface wave dispersion * surface waves Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.699, year: 2016

  9. Improving Seismic Velocity Models with Constraints from Autocorrelation of Ambient Seismic Noise and Signal

    Science.gov (United States)

    2016-03-24

    AFRL-RV-PS- AFRL-RV-PS- TR-2016-0098 TR-2016-0098 IMPROVING SEISMIC VELOCITY MODELS WITH CONSTRAINTS FROM AUTOCORRELATION OF AMBIENT SEISMIC ...TYPE Final Report 3. DATES COVERED (From - To) 24 Apr 2014 – 24 Mar 2016 4. TITLE AND SUBTITLE Improving Seismic Velocity Models with Constraints from...Autocorrelation of Ambient Seismic Noise and Signal 5a. CONTRACT NUMBER FA9453-14-C-0214 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62601F 6

  10. Time-lapse videos for physics education: specific examples

    Science.gov (United States)

    Vollmer, Michael; Möllmann, Klaus-Peter

    2018-05-01

    There are many physics experiments with long time scales such that they are usually neither shown in the physics class room nor in student labs. However, they can be easily recorded with time-lapse cameras and the respective time-lapse videos allow qualitative and/or quantitative analysis of the underlying physics. Here, we present some examples from thermal physics (melting, evaporation, cooling) as well as diffusion processes

  11. Seismic Tomography and the Development of a State Velocity Profile

    Science.gov (United States)

    Marsh, S. J.; Nakata, N.

    2017-12-01

    Earthquakes have been a growing concern in the State of Oklahoma in the last few years and as a result, accurate earthquake location is of utmost importance. This means using a high resolution velocity model with both lateral and vertical variations. Velocity data is determined using ambient noise seismic interferometry and tomography. Passive seismic data was acquired from multiple IRIS networks over the span of eight years (2009-2016) and filtered for earthquake removal to obtain the background ambient noise profile for the state. Seismic Interferometry is applied to simulate ray paths between stations, this is done with each possible station pair for highest resolution. Finally the method of seismic tomography is used to extract the velocity data and develop the state velocity map. The final velocity profile will be a compilation of different network analyses due to changing station availability from year to year. North-Central Oklahoma has a dense seismic network and has been operating for the past few years. The seismic stations are located here because this is the most seismically active region. Other parts of the state have not had consistent coverage from year to year, and as such a reliable and high resolution velocity profile cannot be determined from this network. However, the Transportable Array (TA) passed through Oklahoma in 2014 and provided a much wider and evenly spaced coverage. The goal of this study is to ultimately combine these two arrays over time, and provide a high quality velocity profile for the State of Oklahoma.

  12. Land time-lapse CSEM : Collecting, modeling and inversion of CSEM data for a steam-injected oil field

    NARCIS (Netherlands)

    Schaller, A.M.

    2018-01-01

    Geophysical methods are widely used for hydrocarbon exploration and time-lapse measurements. One method that can be applied in place of or in addition to the routinely used seismic method, is the Controlled-Source ElectroMagnetic (CSEM) method. The work described in this thesis explores various

  13. The structural significance of seismic velocity reversals - an overview

    African Journals Online (AJOL)

    The basic property under investigation is the change of seismic velocity from one layer to the other. This paper looks into problems of velocity reversal, locations of low velocity zones, delineation methods, and presents case studies in the Niger Delta. This study therefore aims at delineating from the surface the subsurface ...

  14. Calibrating vadose zone models with time-lapse gravity data

    DEFF Research Database (Denmark)

    Christiansen, Lars; Binning, Philip John; Rosbjerg, Dan

    2011-01-01

    The vadose zone plays an important role in the hydrologic cycle. Various geophysical methods can determine soil water content variations in time and space in volumes ranging from a few cubic centimeters to several cubic meters. In contrast to the established methods, time-lapse gravity measurements...... hydrologic information. In this study, changes in the soil water content gave rise to a measurable signal in a forced infiltration experiment on a 107-m2 grassland area. Time-lapse gravity data were able to constrain the van Genuchten soil hydraulic parameters in both a synthetic example and a field...

  15. The SCEC Unified Community Velocity Model (UCVM) Software Framework for Distributing and Querying Seismic Velocity Models

    Science.gov (United States)

    Maechling, P. J.; Taborda, R.; Callaghan, S.; Shaw, J. H.; Plesch, A.; Olsen, K. B.; Jordan, T. H.; Goulet, C. A.

    2017-12-01

    Crustal seismic velocity models and datasets play a key role in regional three-dimensional numerical earthquake ground-motion simulation, full waveform tomography, modern physics-based probabilistic earthquake hazard analysis, as well as in other related fields including geophysics, seismology, and earthquake engineering. The standard material properties provided by a seismic velocity model are P- and S-wave velocities and density for any arbitrary point within the geographic volume for which the model is defined. Many seismic velocity models and datasets are constructed by synthesizing information from multiple sources and the resulting models are delivered to users in multiple file formats, such as text files, binary files, HDF-5 files, structured and unstructured grids, and through computer applications that allow for interactive querying of material properties. The Southern California Earthquake Center (SCEC) has developed the Unified Community Velocity Model (UCVM) software framework to facilitate the registration and distribution of existing and future seismic velocity models to the SCEC community. The UCVM software framework is designed to provide a standard query interface to multiple, alternative velocity models, even if the underlying velocity models are defined in different formats or use different geographic projections. The UCVM framework provides a comprehensive set of open-source tools for querying seismic velocity model properties, combining regional 3D models and 1D background models, visualizing 3D models, and generating computational models in the form of regular grids or unstructured meshes that can be used as inputs for ground-motion simulations. The UCVM framework helps researchers compare seismic velocity models and build equivalent simulation meshes from alternative velocity models. These capabilities enable researchers to evaluate the impact of alternative velocity models in ground-motion simulations and seismic hazard analysis applications

  16. Time-lapse controlled-source electromagnetics using interferometry

    NARCIS (Netherlands)

    Hunziker, J.W.; Slob, E.C.; Wapenaar, C.P.A.

    In time-lapse controlled-source electromagnetics, it is crucial that the source and the receivers are positioned at exactly the same location at all times of measurement. We use interferometry by multidimensional deconvolution (MDD) to overcome problems in repeatability of the source location.

  17. TimeLapseAnalyzer: Multi-target analysis for live-cell imaging and time-lapse microscopy

    DEFF Research Database (Denmark)

    Huth, Johannes; Buchholz, Malte; Kraus, Johann M.

    2011-01-01

    The direct observation of cells over time using time-lapse microscopy can provide deep insights into many important biological processes. Reliable analyses of motility, proliferation, invasive potential or mortality of cells are essential to many studies involving live cell imaging and can aid...

  18. Definition of "banner clouds" based on time lapse movies

    Directory of Open Access Journals (Sweden)

    J. H. Schween

    2007-01-01

    Full Text Available Banner clouds appear on the leeward side of a mountain and resemble a banner or a flag. This article provides a comprehensive definition of "banner clouds". It is based primarily on an extensive collection of time lapse movies, but previous attempts at an explanation of this phenomenon are also taken into account. The following ingredients are considered essential: the cloud must be attached to the mountain but not appear on the windward side; the cloud must originate from condensation of water vapour contained in the air (rather than consist of blowing snow; the cloud must be persistent; and the cloud must not be of convective nature. The definition is illustrated and discussed with the help of still images and time lapse movies taken at Mount Zugspitze in the Bavarian Alps.

  19. Definition of "banner clouds" based on time lapse movies

    OpenAIRE

    Schween , J. H.; Kuettner , J.; Reinert , D.; Reuder , J.; Wirth , V.

    2007-01-01

    International audience; Banner clouds appear on the leeward side of a mountain and resemble a banner or a flag. This article provides a comprehensive definition of "banner clouds". It is based primarily on an extensive collection of time lapse movies, but previous attempts at an explanation of this phenomenon are also taken into account. The following ingredients are considered essential: the cloud must be attached to the mountain but not appear on the windward side; the cloud must originate ...

  20. The Use Of Seismic Velocities For The Prediction Of Abnormal ...

    African Journals Online (AJOL)

    Ninety (90) velocity control points derived from seismic data processing were examined and analyzed to evaluate abnormal pressure zones in parts of onshore western Niger - Delta. Compaction trend graphs and a map showing the distribution of top of overpressure were produced. The graphs show that compaction ...

  1. Iterative reflectivity-constrained velocity estimation for seismic imaging

    Science.gov (United States)

    Masaya, Shogo; Verschuur, D. J. Eric

    2018-03-01

    This paper proposes a reflectivity constraint for velocity estimation to optimally solve the inverse problem for active seismic imaging. This constraint is based on the velocity model derived from the definition of reflectivity and acoustic impedance. The constraint does not require any prior information of the subsurface and large extra computational costs, like the calculation of so-called Hessian matrices. We incorporate this constraint into the Joint Migration Inversion algorithm, which simultaneously estimates both the reflectivity and velocity model of the subsurface in an iterative process. Using so-called full wavefield modeling, the misfit between forward modeled and measured data is minimized. Numerical and field data examples are given to demonstrate the validity of our proposed algorithm in case accurate initial models and the low frequency components of observed seismic data are absent.

  2. MSNoise: a Python Package for Monitoring Seismic Velocity Changes using Ambient Seismic Noise

    Science.gov (United States)

    Lecocq, Thomas; Caudron, Corentin; Brenguier, Florent

    2014-05-01

    We present MSNoise, a complete software suite to compute relative seismic velocity changes under a seismic network, using ambient seismic noise. The whole is written in Python, from the monitoring of data archives, to the production of high quality figures. All steps have been optimized to only compute the necessary steps and to use 'job'-based processing. All steps can be changed by matching the in/outs. MSNoise exposes an API for communication with the data archive and the database. We present a validation of the software on a dataset acquired during the UnderVolc project on the Piton de la Fournaise Volcano, La Réunion Island, France, for which precursory relative changes of seismic velocity are visible for three eruptions betwee 2009 and 2011. MSNoise is available on http://www.msnoise.org

  3. Seismic velocity models for an internally asymmetric Mars

    Science.gov (United States)

    Franck, S.; Kowalle, G.

    1994-01-01

    The well-known dichotomy in topography, surface age, and crustal structure between the northern lowlands and the southern uplands of Mars has been explained by both endogenic and exogenic processes. According to the used model this asymmetry might be a result of a certain mechanism of core formation influencing the following planetary evolution. Therefore it has been assumed that the present internal structure of Mars is characterized by different velocity-depth distributions of the mantle for the northern and southern hemisphere, respectively. For both regions significant differences in travel times of seismic waves were calculated. These results may be important for the future seismic exploration of Mars.

  4. Mycoplasma infection followed by time-lapse microscopy.

    Science.gov (United States)

    Talas, Laszlo; Banfalvi, Gaspar; Fidrus, Eszter; Szigeti, Zsuzsa M; Nagy, Gabor

    2017-10-01

    Early detection of mycoplasma infection is crucial for saving precious often irreplaceable data from the tissues of patients. Mycoplasma infections cause diseases in the upper and lower respiratory tracts, urethritis in men resulting in painful dysuria, urgency and urethral discharge. Cough, fever, headache, urethritis may persist for several weeks and convalescence is slow. The symptoms of these diseases are aggravated by the detection of mycoplasma infections, that takes either a long time, besides being expensive or is specific and restricted to only a limited number of contaminant strains. Mycoplasmas are hard to detect visually but could be seen and followed by time-lapse microscopy. Our hypothesis is that one can detect mycoplasma infection irrespective of its origin and type of mycoplasma. Main lines of supporting evidence are provided by the time-lapse microscopy showing dynamic morphological alterations caused by mycoplasmas before changes in human cell cultures become visible. Morphometric measurements of mycoplasma infections revealed four subphases: i) detachment of infected cells, ii) aggregation, iii) biofilm formation and iv) shrinkage of infected cells. The applicability of time-lapse microscopy for the detection of mycoplasma infection was validated by a mycoplasma test Kit. Most important implications related to morphometric parameters include the observation of mycoplasma infected cultures for an extended period of time instead of applying static snap-shot microscopy. A reliable method is offered to estimate the time of mycoplasma exposure that elapsed during the cell growth. This microphotometric approach served a more economical detection of mycoplasma contamination at its early stage of cell growth and spread, irrespective of the origin of contaminated serum, without defining the type of mycoplasma. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Time-lapse microscopy of lung endothelial cells under hypoxia

    Science.gov (United States)

    Mehrvar, Shima; Ghanian, Zahra; Kondouri, Ganesh; Camara, Amadou S.; Ranji, Mahsa

    2017-02-01

    Objective: This study utilizes fluorescence microscopy to assess the effect of the oxygen tension on the production of reactive oxygen species (ROS) in mitochondria of fetal pulmonary artery endothelial cells (FPAECs). Introduction: Hypoxia is a severe oxygen stress, which mostly causes irreversible injury in lung cells. However, in some studies, it is reported that hypoxia decreases the severity of injuries. In this study, ROS production level was examined in hypoxic FPAECs treated with pentachlorophenol (PCP, uncoupler). This work was accomplished by monitoring and quantifying the changes in the level of the produced ROS in hypoxic cells before and after PCP treatment. Materials and methods: The dynamic of the mitochondrial ROS production in two groups of FPAECs was measured over time using time-lapse microscopy. For the first group, cells were incubated in 3% hypoxic condition for 2 hours and then continuously were exposed to hypoxic condition for imaging as well. For the second group, cells were incubated in normal oxygen condition. Time lapse images of the cells loaded with Mito-SOX (ROS indicator) were acquired, and the red fluorescence intensity profile of the cells was calculated. Changes in the level of the fluorescence intensity profile while they are treated with PCP indicates the dynamics of the ROS level. Results: The intensity profiles of the PCP-treated cells in the first group showed 47% lower ROS production rate than the PCP-treated cells in the second group. Conclusion: Time lapse microscopy revealed that hypoxic cells have lower ROS generation while treated with PCP. Therefore, this result suggests that hypoxia decreased electron transport chain activity in uncoupled chain.

  6. Velocity Structure in the West Bohemia Seismic Zone: Velocity Models Retrieved from different Earthquake Swarms

    Science.gov (United States)

    Alexandrakis, C.; Löberich, E.; Kieslich, A.; Calo, M.; Vavrycuk, V.; Buske, S.

    2015-12-01

    Earthquake swarms, fluid migration and gas springs are indications of the ongoing geodynamic processes within the West Bohemia seismic zone located at the Czech-German border. The possible relationship between the fluids, gas and seismicity is of particular interest and has motivated numerous past, ongoing and future studies, including a multidisciplinary monitoring proposal through the International Continental Scientific Drilling Program (ICDP). The most seismically active area within the West Bohemia seismic zone is located at the Czech town Nový Kostel. The Nový Kostel zone experiences frequent swarms of several hundreds to thousands of earthquakes over a period of weeks to several months. The seismicity is always located in the same area and depth range (~5-15 km), however the activated fault segments and planes differ. For example, the 2008 swarm activated faults along the southern end of the seismic zone, the 2011 swarm activated the northern segment, and the recent 2014 swarm activated the middle of the seismic zone. This indicates changes to the local stress field, and may relate to fluid migration and/or the complicated tectonic situation. The West Bohemia Seismic Network (WEBNET) is ideally located for studying the Nový Kostel swarm area and provides good azimuthal coverage. Here, we use the high quality P- and S-wave arrival picks recorded by WEBNET to calculate swarm-dependent velocity models for the 2008 and 2011 swarms, and an averaged (swarm independent) model using earthquakes recorded between 1991 and 2011. To this end, we use double-difference tomography to calculate P- and S-wave velocity models. The models are compared and examined in terms of swarm-dependent velocities and structures. Since the P-to-S velocity ratio is particularly sensitive to the presence of pore fluids, we derive ratio models directly from the inverted P- and S-wave models in order to investigate the potential influence of fluids on the seismicity. Finally, clustering

  7. A software solution for recording circadian oscillator features in time-lapse live cell microscopy

    Directory of Open Access Journals (Sweden)

    Salmon Patrick

    2010-07-01

    Full Text Available Abstract Background Fluorescent and bioluminescent time-lapse microscopy approaches have been successfully used to investigate molecular mechanisms underlying the mammalian circadian oscillator at the single cell level. However, most of the available software and common methods based on intensity-threshold segmentation and frame-to-frame tracking are not applicable in these experiments. This is due to cell movement and dramatic changes in the fluorescent/bioluminescent reporter protein during the circadian cycle, with the lowest expression level very close to the background intensity. At present, the standard approach to analyze data sets obtained from time lapse microscopy is either manual tracking or application of generic image-processing software/dedicated tracking software. To our knowledge, these existing software solutions for manual and automatic tracking have strong limitations in tracking individual cells if their plane shifts. Results In an attempt to improve existing methodology of time-lapse tracking of a large number of moving cells, we have developed a semi-automatic software package. It extracts the trajectory of the cells by tracking theirs displacements, makes the delineation of cell nucleus or whole cell, and finally yields measurements of various features, like reporter protein expression level or cell displacement. As an example, we present here single cell circadian pattern and motility analysis of NIH3T3 mouse fibroblasts expressing a fluorescent circadian reporter protein. Using Circadian Gene Express plugin, we performed fast and nonbiased analysis of large fluorescent time lapse microscopy datasets. Conclusions Our software solution, Circadian Gene Express (CGE, is easy to use and allows precise and semi-automatic tracking of moving cells over longer period of time. In spite of significant circadian variations in protein expression with extremely low expression levels at the valley phase, CGE allows accurate and

  8. Spatial and temporal variation of seismic velocity during earthquakes and volcanic eruptions in western Japan: Insight into mechanism for seismic velocity variation

    Science.gov (United States)

    Tsuji, T.; Ikeda, T.; Nimiya, H.

    2017-12-01

    We report spatio-temporal variations of seismic velocity around the seismogenic faults in western Japan. We mainly focus on the seismic velocity variation during (1) the 2016 Off-Mie earthquake in the Nankai subduction zone (Mw5.8) and (2) the 2016 Kumamoto earthquake in Kyushu Island (Mw7.0). We applied seismic interferometry and surface wave analysis to the ambient noise data recorded by Hi-net and DONET seismometers of National Research Institute for Earth Science and Disaster Resilience (NIED). Seismic velocity near the rupture faults and volcano decreased during the earthquake. For example, we observed velocity reduction around the seismogenic Futagawa-Hinagu fault system and Mt Aso in the 2016 Kumamoto earthquake. We also identified velocity increase after the eruptions of Mt Aso. During the 2016 Off-Mie earthquake, we observed seismic velocity variation in the Nankai accretionary prism. After the earthquakes, the seismic velocity gradually returned to the pre-earthquake value. The velocity recovering process (healing process) is caused by several mechanisms, such as pore pressure reduction, strain change, and crack sealing. By showing the velocity variations obtained at different geologic settings (volcano, seismogenic fault, unconsolidated sediment), we discuss the mechanism of seismic velocity variation as well as the post-seismic fault healing process.

  9. Peak Ground Velocities for Seismic Events at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    K. Coppersmith; R. Quittmeyer

    2005-02-16

    This report describes a scientific analysis to bound credible horizontal peak ground velocities (PGV) for the repository waste emplacement level at Yucca Mountain. Results are presented as a probability distribution for horizontal PGV to represent uncertainties in the analysis. The analysis also combines the bound to horizontal PGV with results of ground motion site-response modeling (BSC 2004 [DIRS 170027]) to develop a composite hazard curve for horizontal PGV at the waste emplacement level. This result provides input to an abstraction of seismic consequences (BSC 2004 [DIRS 169183]). The seismic consequence abstraction, in turn, defines the input data and computational algorithms for the seismic scenario class of the total system performance assessment (TSPA). Planning for the analysis is documented in Technical Work Plan TWP-MGR-GS-000001 (BSC 2004 [DIRS 171850]). The bound on horizontal PGV at the repository waste emplacement level developed in this analysis complements ground motions developed on the basis of PSHA results. In the PSHA, ground motion experts characterized the epistemic uncertainty and aleatory variability in their ground motion interpretations. To characterize the aleatory variability they used unbounded lognormal distributions. As a consequence of these characterizations, as seismic hazard calculations are extended to lower and lower annual frequencies of being exceeded, the ground motion level increases without bound, eventually reaching levels that are not credible (Corradini 2003 [DIRS 171191]). To provide credible seismic inputs for TSPA, in accordance with 10 Code of Federal Regulations (CFR) 63.102(j) [DIRS 156605], this complementary analysis is carried out to determine reasonable bounding values of horizontal PGV at the waste emplacement level for annual frequencies of exceedance as low as 10{sup -8}. For each realization of the TSPA seismic scenario, the results of this analysis provide a constraint on the values sampled from the

  10. Seismic Velocity Anomalies beneath Tatun Volcano Group, Northern Taiwan

    Science.gov (United States)

    Lin, Tzu-yu; Lin, Cheng-Horng; Yang, Tsanyao Frank; Chang, Li-Chin

    2015-04-01

    Volcanic eruption has been a natural disaster for human society. Taiwan is located in the Pacific Ring of Fire. Although there is no obvious phenomenon of volcanic activity in Taiwan, some volcanoes need to be monitored, especially the Tatun Volcano Group (TVG), which exhibits very active hydrothermal activity, is located on the tip of southwestern Ryukyu arc. TVG is about 15 km north to Taipei, capital of Taiwan, and is nearby two nuclear power plants along the northern coast of Taiwan. If TVG erupts, there must be a serious impact and damage to Taiwan. Since TVG is located within the Yangmingshan National Park, any artificial seismic source is not allowed to estimate possible eruption site and the degree of volcanic disaster. Instead, we use natural seismic waves generated by earthquakes to image the possible velocity anomaly of magma chamber and/or hydrothermal system beneath TVG. We systematically compare the differences of arrival times generated by some local earthquakes and recorded at 42 seismic stations in 2014 for finding any low-velocity zone within the crust. The results show that the arrival times always appeared significant delay at some particular seismic stations, such as Chi-Hsin-Shan (CHS), Siao-You-Keng (SYK) and some other stations at TVG, no matter where the earthquakes occurred. It implies that possible low-velocity zones, which could be the location of magma chamber and/or active hydrothermal system, exist beneath the CHS and SYK areas. This feature is generally consistent with the clustered micro-earthquakes in the shallow crust beneath the CHS area in the last decade.

  11. Improved detection of preeruptive seismic velocity drops at the Piton de La Fournaise volcano

    Science.gov (United States)

    Rivet, Diane; Brenguier, Florent; Cappa, Frédéric

    2015-08-01

    The unexpected 2014 and 2015 Ontake (Japan) and Calbuco (Chile) eruptions proved that improving volcanic eruption prediction is still a great challenge. Decreases of seismic velocities of the Piton de la Fournaise volcano inferred from seismic noise correlations have been shown to precede eruptions. However, seismic velocities are strongly influenced by rainfall and subsequent pore pressure perturbations. Here we increase the detection of precursory seismic velocity changes to an eruption by removing the effects of pore pressure changes. During 2011-2013, the volcano exhibits a low eruptive activity during which we observe seismic velocity variations well correlated with rainfall episodes. We estimated the transfer function between fluid pressure and seismic velocity changes. We use these results to correct seismic velocity change time series for pore pressure changes, due to rainfall and found a preeruptive velocity drop (0.15%) associated with the 21 June 2014 eruption that was undetected before correction.

  12. Combined time-lapse cinematography and immuno-electron microscopy.

    Science.gov (United States)

    Balfour, B M; Goscicka, T; MacKenzie, J L; Gautam, A; Tate, M; Clark, J

    1990-04-01

    A method was developed to record interactions between mobile non-adherent immunocytes by time-lapse cinematography and then to study the same cells by immuno-electron microscopy, using monoclonal antibodies against surface components. For this purpose a modified stage was designed to fit an inverted microscope. The attachment included a device to cool the culture chamber with N2 gas, a micro-injector for monoclonal antibody and immuno-gold treatment, and two pairs of washing needles to change the medium without disturbance. The technique was first employed to study the formation of aggregates around the antigen-presenting cells in cultures containing cells from hyper-immunized animals. Recently peripheral blood cells from normal subjects and patients with immune deficiency syndromes were stimulated with pokeweed mitogen, cluster formation was recorded, and the cells were processed for immuno-electron microscopy.

  13. Seismic Velocity and Elastic Properties of Plate Boundary Faults

    Science.gov (United States)

    Jeppson, Tamara N.

    The elastic properties of fault zone rock at depth play a key role in rupture nucleation, propagation, and the magnitude of fault slip. Materials that lie within major plate boundary fault zones often have very different material properties than standard crustal rock values. In order to understand the mechanics of faulting at plate boundaries, we need to both measure these properties and understand how they govern the behavior of different types of faults. Mature fault zones tend to be identified in large-scale geophysical field studies as zones with low seismic velocity and/or electrical resistivity. These anomalous properties are related to two important mechanisms: (1) mechanical or diagenetic alteration of the rock materials and/or (2) pore fluid pressure and stress effects. However, in remotely-sensed and large-length-scale data it is difficult to determine which of these mechanisms are affecting the measured properties. The objective of this dissertation research is to characterize the seismic velocity and elastic properties of fault zone rocks at a range of scales, with a focus on understanding why the fault zone properties are different from those of the surrounding rock and the potential effects on earthquake rupture and fault slip. To do this I performed ultrasonic velocity experiments under elevated pressure conditions on drill core and outcrops samples from three plate boundary fault zones: the San Andreas Fault, California, USA; the Alpine Fault, South Island, New Zealand; and the Japan Trench megathrust, Japan. Additionally, I compared laboratory measurements to sonic log and large-scale seismic data to examine the scale-dependence of the measured properties. The results of this study provide the most comprehensive characterization of the seismic velocities and elastic properties of fault zone rocks currently available. My work shows that fault zone rocks at mature plate boundary faults tend to be significantly more compliant than surrounding crustal

  14. Dust Storm Time Lapse Shows Opportunity's Skies Darken

    Science.gov (United States)

    2007-01-01

    [figure removed for brevity, see original site] Dust Storm Time Lapse Shows Opportunity's Skies Darken NASA's Opportunity rover is literally seeing some of its darkest days. Both Mars Exploration Rovers have been riding out a regional dust storm for several weeks. Conditions became particularly dreary in the Meridiani Planum region where Opportunity sits, perched on the edge of 'Victoria Crater.' This image is a time-lapse composite where each horizon-survey image has been compressed horizontally (but not vertically) to emphasize the sky. The relative brightness and darkness of the sky from sol to sol (over a 30-sol period beginning June 14, 2007) is depicted accurately in these images, which view roughly the same part of the plains southwest of the rover. The images are approximately true color composites, generated from calibrated radiance data files using the panoramic camera's 601-nanometer, 535-nanometer and 482-nanometer filters. The rovers' atmospheric science team is concerned that smaller, regional dust storms could expand into a larger, globe-encircling storm. That could extend the time the sun stays obscured, challenging the capability of Opportunity's solar panels to produce enough electricity for the rover to function. Fortunately, as of July 19, 2007, the Opportunity site is clearing slightly. When the storm ends, atmospheric scientists hope to review data from the rovers that will help them determine what sort of dust was being lifted and distributed. The numbers across the top of the image report a measurement of atmospheric opacity, called by the Greek letter tau. The lower the number, the clearer the sky. Both Opportunity and Spirit have been recording higher tau measurements in July 2007 than they had seen any time previously in their three and a half years on Mars. The five sol numbers across the bottom correspond (left to right) to June 14, June 30, July 5, July 13 and July 15, 2007.

  15. Wave-equation migration velocity inversion using passive seismic sources

    Science.gov (United States)

    Witten, B.; Shragge, J. C.

    2015-12-01

    Seismic monitoring at injection sites (e.g., CO2 sequestration, waste water disposal, hydraulic fracturing) has become an increasingly important tool for hazard identification and avoidance. The information obtained from this data is often limited to seismic event properties (e.g., location, approximate time, moment tensor), the accuracy of which greatly depends on the estimated elastic velocity models. However, creating accurate velocity models from passive array data remains a challenging problem. Common techniques rely on picking arrivals or matching waveforms requiring high signal-to-noise data that is often not available for the magnitude earthquakes observed over injection sites. We present a new method for obtaining elastic velocity information from earthquakes though full-wavefield wave-equation imaging and adjoint-state tomography. The technique exploits the fact that the P- and S-wave arrivals originate at the same time and location in the subsurface. We generate image volumes by back-propagating P- and S-wave data through initial Earth models and then applying a correlation-based extended-imaging condition. Energy focusing away from zero lag in the extended image volume is used as a (penalized) residual in an adjoint-state tomography scheme to update the P- and S-wave velocity models. We use an acousto-elastic approximation to greatly reduce the computational cost. Because the method requires neither an initial source location or origin time estimate nor picking of arrivals, it is suitable for low signal-to-noise datasets, such as microseismic data. Synthetic results show that with a realistic distribution of microseismic sources, P- and S-velocity perturbations can be recovered. Although demonstrated at an oil and gas reservoir scale, the technique can be applied to problems of all scales from geologic core samples to global seismology.

  16. Seismic velocity and crustal thickness inversions: Moon and Mars

    Science.gov (United States)

    Drilleau, Melanie; Blanchette-Guertin, Jean-François; Kawamura, Taichi; Lognonné, Philippe; Wieczorek, Mark

    2017-04-01

    We present results from new inversions of seismic data arrival times acquired by the Apollo active and passive experiments. Markov chain Monte Carlo inversions are used to constrain (i) 1-D lunar crustal and upper mantle velocity models and (ii) 3-D lateral crustal thickness models under the Apollo stations and the artificial and natural impact sites. A full 3-D model of the lunar crustal thickness is then obtained using the GRAIL gravimetric data, anchored by the crustal thicknesses under each Apollo station and impact site. To avoid the use of any seismic reference model, a Bayesian inversion technique is implemented. The advantage of such an approach is to obtain robust probability density functions of interior structure parameters governed by uncertainties on the seismic data arrival times. 1-D seismic velocities are parameterized using C1-Bézier curves, which allow the exploration of both smoothly varying models and first-order discontinuities. The parameters of the inversion include the seismic velocities of P and S waves as a function of depth, the thickness of the crust under each Apollo station and impact epicentre. The forward problem consists in a ray tracing method enabling both the relocation of the natural impact epicenters, and the computation of time corrections associated to the surface topography and the crustal thickness variations under the stations and impact sites. The results show geology-related differences between the different sites, which are due to contrasts in megaregolith thickness and to shallow subsurface composition and structure. Some of the finer structural elements might be difficult to constrain and might fall within the uncertainties of the dataset. However, we use the more precise LROC-located epicentral locations for the lunar modules and Saturn-IV upper stage artificial impacts, reducing some of the uncertainties observed in past studies. In the framework of the NASA InSight/SEIS mission to Mars, the method developed in

  17. On the Resolvability of Steam Assisted Gravity Drainage Reservoirs Using Time-Lapse Gravity Gradiometry

    Science.gov (United States)

    Elliott, E. Judith; Braun, Alexander

    2017-11-01

    Unconventional heavy oil resource plays are important contributors to oil and gas production, as well as controversial for posing environmental hazards. Monitoring those reservoirs before, during, and after operations would assist both the optimization of economic benefits and the mitigation of potential environmental hazards. This study investigates how gravity gradiometry using superconducting gravimeters could resolve depletion areas in steam assisted gravity drainage (SAGD) reservoirs. This is achieved through modelling of a SAGD reservoir at 1.25 and 5 years of operation. Specifically, the density change structure identified from geological, petrological, and seismic observations is forward modelled for gravity and gradients. Three main parameters have an impact on the resolvability of bitumen depletion volumes and are varied through a suitable parameter space: well pair separation, depth to the well pairs, and survey grid sampling. The results include a resolvability matrix, which identifies reservoirs that could benefit from time-lapse gravity gradiometry monitoring. After 1.25 years of operation, during the rising phase, the resolvable maximum reservoir depth ranges between the surface and 230 m, considering a well pair separation between 80 and 200 m. After 5 years of production, during the spreading phase, the resolvability of depletion volumes around single well pairs is greatly compromised as the depletion volume is closer to the surface, which translates to a larger portion of the gravity signal. The modelled resolvability matrices were derived from visual inspection and spectral analysis of the gravity gradient signatures and can be used to assess the applicability of time-lapse gradiometry to monitor reservoir density changes.

  18. Time lapse gravity monitoring at Coso geothermal field

    Science.gov (United States)

    Woolf, Rachel Vest

    An extensive time lapse gravity data set was acquired over the Coso geothermal field near Ridgecrest, California starting in 1987, with the latest data set acquired in 2013. In this thesis I use these gravity data to obtain a better understanding of mass changes occurring within the geothermal field. Geothermal energy is produced by flashing naturally heated ground water into steam which is used to turn turbines. Brine and re-condensed steam are then re-injected into the reservoir. A percentage of the water removed from the system is lost to the process. The time lapse gravity method consists of gravity measurements taken at the same locations over time, capturing snap shots of the changing field. After careful processing, the final data are differenced to extract the change in gravity over time. This change in gravity can then be inverted to recover the change in density and therefore mass over time. The inversion process also produces information on the three dimensional locations of these mass changes. Thirty five gravity data sets were processed and a subsection were inverted with two different starting times, a sixteen point data set collected continuously between 1991 and 2005, and a thirty-eight point data set collected between 1996 and 2005. The maximum change in gravity in the 1991 data group was -350 microGal observed near station CSE2. For the 1996 data group the maximum gravity change observed over the nine year period was -248 microGal. The gravity data were then inverted using the surface inversion method. Three values of density contrast were used, -0.05 g/cm3, -0.10 g/cm3, and -0.20 g/cm3. The starting surface in 1991 was set to 2,500 ft above sea level. The changes in surfaces were then converted to mass changes. The largest total mass change recovered was -1.39x1011 kg. This mass value is of the same order of magnitude as published well production data for the field. Additionally, the gravity data produces a better understanding of the spatial

  19. Network Analysis of Time-Lapse Microscopy Recordings

    Directory of Open Access Journals (Sweden)

    Erik eSmedler

    2014-09-01

    Full Text Available Multicellular organisms rely on intercellular communication to regulate important cellular processes critical to life. To further our understanding of those processes there is a need to scrutinize dynamical signaling events and their functions in both cells and organisms. Here, we report a method and provide MATLAB code that analyzes time-lapse microscopy recordings to identify and characterize network structures within large cell populations, such as interconnected neurons. The approach is demonstrated using intracellular calcium (Ca2+ recordings in neural progenitors and cardiac myocytes, but could be applied to a wide variety of biosensors employed in diverse cell types and organisms. In this method, network structures are analyzed by applying cross-correlation signal processing and graph theory to single-cell recordings. The goal of the analysis is to determine if the single cell activity constitutes a network of interconnected cells and to decipher the properties of this network. The method can be applied in many fields of biology in which biosensors are used to monitor signaling events in living cells. Analyzing intercellular communication in cell ensembles can reveal essential network structures that provide important biological insights.

  20. Low-cost motility tracking system (LOCOMOTIS) for time-lapse microscopy applications and cell visualisation.

    Science.gov (United States)

    Lynch, Adam E; Triajianto, Junian; Routledge, Edwin

    2014-01-01

    Direct visualisation of cells for the purpose of studying their motility has typically required expensive microscopy equipment. However, recent advances in digital sensors mean that it is now possible to image cells for a fraction of the price of a standard microscope. Along with low-cost imaging there has also been a large increase in the availability of high quality, open-source analysis programs. In this study we describe the development and performance of an expandable cell motility system employing inexpensive, commercially available digital USB microscopes to image various cell types using time-lapse and perform tracking assays in proof-of-concept experiments. With this system we were able to measure and record three separate assays simultaneously on one personal computer using identical microscopes, and obtained tracking results comparable in quality to those from other studies that used standard, more expensive, equipment. The microscopes used in our system were capable of a maximum magnification of 413.6×. Although resolution was lower than that of a standard inverted microscope we found this difference to be indistinguishable at the magnification chosen for cell tracking experiments (206.8×). In preliminary cell culture experiments using our system, velocities (mean µm/min ± SE) of 0.81 ± 0.01 (Biomphalaria glabrata hemocytes on uncoated plates), 1.17 ± 0.004 (MDA-MB-231 breast cancer cells), 1.24 ± 0.006 (SC5 mouse Sertoli cells) and 2.21 ± 0.01 (B. glabrata hemocytes on Poly-L-Lysine coated plates), were measured and are consistent with previous reports. We believe that this system, coupled with open-source analysis software, demonstrates that higher throughput time-lapse imaging of cells for the purpose of studying motility can be an affordable option for all researchers.

  1. Low-cost motility tracking system (LOCOMOTIS for time-lapse microscopy applications and cell visualisation.

    Directory of Open Access Journals (Sweden)

    Adam E Lynch

    Full Text Available Direct visualisation of cells for the purpose of studying their motility has typically required expensive microscopy equipment. However, recent advances in digital sensors mean that it is now possible to image cells for a fraction of the price of a standard microscope. Along with low-cost imaging there has also been a large increase in the availability of high quality, open-source analysis programs. In this study we describe the development and performance of an expandable cell motility system employing inexpensive, commercially available digital USB microscopes to image various cell types using time-lapse and perform tracking assays in proof-of-concept experiments. With this system we were able to measure and record three separate assays simultaneously on one personal computer using identical microscopes, and obtained tracking results comparable in quality to those from other studies that used standard, more expensive, equipment. The microscopes used in our system were capable of a maximum magnification of 413.6×. Although resolution was lower than that of a standard inverted microscope we found this difference to be indistinguishable at the magnification chosen for cell tracking experiments (206.8×. In preliminary cell culture experiments using our system, velocities (mean µm/min ± SE of 0.81 ± 0.01 (Biomphalaria glabrata hemocytes on uncoated plates, 1.17 ± 0.004 (MDA-MB-231 breast cancer cells, 1.24 ± 0.006 (SC5 mouse Sertoli cells and 2.21 ± 0.01 (B. glabrata hemocytes on Poly-L-Lysine coated plates, were measured and are consistent with previous reports. We believe that this system, coupled with open-source analysis software, demonstrates that higher throughput time-lapse imaging of cells for the purpose of studying motility can be an affordable option for all researchers.

  2. Quantifying Effusion Rates at Active Volcanoes through Integrated Time-Lapse Laser Scanning and Photography

    Directory of Open Access Journals (Sweden)

    Neil Slatcher

    2015-11-01

    Full Text Available During volcanic eruptions, measurements of the rate at which magma is erupted underpin hazard assessments. For eruptions dominated by the effusion of lava, estimates are often made using satellite data; here, in a case study at Mount Etna (Sicily, we make the first measurements based on terrestrial laser scanning (TLS, and we also include explosive products. During the study period (17–21 July 2012, regular Strombolian explosions were occurring within the Bocca Nuova crater, producing a ~50 m-high scoria cone and a small lava flow field. TLS surveys over multi-day intervals determined a mean cone growth rate (effusive and explosive products of ~0.24 m3·s−1. Differences between 0.3-m resolution DEMs acquired at 10-minute intervals captured the evolution of a breakout lava flow lobe advancing at 0.01–0.03 m3·s−1. Partial occlusion within the crater prevented similar measurement of the main flow, but integrating TLS data with time-lapse imagery enabled lava viscosity (7.4 × 105 Pa·s to be derived from surface velocities and, hence, a flux of 0.11 m3·s−1 to be calculated. Total dense rock equivalent magma discharge estimates are ~0.1–0.2 m3·s−1 over the measurement period and suggest that simultaneous estimates from satellite data are somewhat overestimated. Our results support the use of integrated TLS and time-lapse photography for ground-truthing space-based measurements and highlight the value of interactive image analysis when automated approaches, such as particle image velocimetry (PIV, fail.

  3. Assessing Uncertainty and Repeatability in Time-Lapse VSP Monitoring of CO2 Injection in a Brine Aquifer, Frio Formation, Texas (A Case Study)

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, Siamak [Univ. of California, Berkeley, CA (United States). Dept. of Civil and Environmental Engineering; Daley, Thomas M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division

    2013-02-07

    This study was done to assess the repeatability and uncertainty of time-lapse VSP response to CO2 injection in the Frio formation near Houston Texas. A work flow was built to assess the effect of time-lapse injected CO2 into two Frio brine reservoir intervals, the ‘C’ sand (Frio1) and the ‘Blue sand’ (Frio2). The time-lapse seismic amplitude variations with sensor depth for both reservoirs Frio1 and Frio2 were computed by subtracting the seismic response of the base survey from each of the two monitor seismic surveys. Source site 1 has been considered as one of the best sites for evaluating the time-lapse response after injection. For site 1, the computed timelapse NRMS levels after processing had been compared to the estimated time-lapse NRMS level before processing for different control reflectors, and for brine aquifers Frio1, and Frio2 to quantify detectability of amplitude difference. As the main interest is to analyze the time-lapse amplitude variations, different scenarios have been considered. Three different survey scenarios were considered: the base survey which was performed before injection, monitor1 performed after the first injection operation, and monitor2 which was after the second injection. The first scenario was base-monitor1, the second was basemonitor2, and the third was monitor1-monitor2. We considered three ‘control’ reflections above the Frio to assist removal of overburden changes, and concluded that third control reflector (CR3) is the most favorable for the first scenario in terms of NRMS response, and first control reflector (CR1) is the most favorable for the second and third scenarios in terms of NRMS response. The NRMS parameter is shown to be a useful measure to assess the effect of processing on time-lapse data. The overall NRMS for the Frio VSP data set was found to be in the range of 30% to 80% following basic processing. This could be considered as an estimated baseline in assessing the utility

  4. Exploring Time-Lapse Photography as a Means for Qualitative Data Collection

    Science.gov (United States)

    Persohn, Lindsay

    2015-01-01

    Collecting information via time-lapse photography is nothing new. Scientists and artists have been using this kind of data since the late 1800s. However, my research and experiments with time-lapse have shown that great potential may lie in its application to educational and social scientific research methods. This article is part history, part…

  5. Capturing change: the duality of time-lapse imagery to acquire data and depict ecological dynamics

    Science.gov (United States)

    Brinley Buckley, Emma M.; Allen, Craig R.; Forsberg, Michael; Farrell, Michael; Caven, Andrew J.

    2017-01-01

    We investigate the scientific and communicative value of time-lapse imagery by exploring applications for data collection and visualization. Time-lapse imagery has a myriad of possible applications to study and depict ecosystems and can operate at unique temporal and spatial scales to bridge the gap between large-scale satellite imagery projects and observational field research. Time-lapse data sequences, linking time-lapse imagery with data visualization, have the ability to make data come alive for a wider audience by connecting abstract numbers to images that root data in time and place. Utilizing imagery from the Platte Basin Timelapse Project, water inundation and vegetation phenology metrics are quantified via image analysis and then paired with passive monitoring data, including streamflow and water chemistry. Dynamic and interactive time-lapse data sequences elucidate the visible and invisible ecological dynamics of a significantly altered yet internationally important river system in central Nebraska.

  6. Capturing change: the duality of time-lapse imagery to acquire data and depict ecological dynamics

    Directory of Open Access Journals (Sweden)

    Emma M. Brinley Buckley

    2017-09-01

    Full Text Available We investigate the scientific and communicative value of time-lapse imagery by exploring applications for data collection and visualization. Time-lapse imagery has a myriad of possible applications to study and depict ecosystems and can operate at unique temporal and spatial scales to bridge the gap between large-scale satellite imagery projects and observational field research. Time-lapse data sequences, linking time-lapse imagery with data visualization, have the ability to make data come alive for a wider audience by connecting abstract numbers to images that root data in time and place. Utilizing imagery from the Platte Basin Timelapse Project, water inundation and vegetation phenology metrics are quantified via image analysis and then paired with passive monitoring data, including streamflow and water chemistry. Dynamic and interactive time-lapse data sequences elucidate the visible and invisible ecological dynamics of a significantly altered yet internationally important river system in central Nebraska.

  7. Monitoring Seismic Velocity Change to Explore the Earthquake Seismogenic Structures

    Science.gov (United States)

    Liao, C. F.; Wen, S.; Chen, C.

    2017-12-01

    Studying spatial-temporal variations of subsurface velocity structures is still a challenge work, but it can provide important information not only on geometry of a fault, but also the rheology change induced from the strong earthquake. In 1999, a disastrous Chi-Chi earthquake (Mw7.6; Chi-Chi EQ) occurred in central Taiwan and caused great impacts on Taiwan's society. Therefore, the major objective of this research is to investigate whether the rheology change of fault can be associated with seismogenic process before strong earthquake. In addition, after the strike of the Chi-Chi EQ, whether the subsurface velocity structure resumes to its steady state is another issue in this study. Therefore, for the above purpose, we have applied a 3D tomographic technique to obtain P- and S-wave velocity structures in central Taiwan using travel time data provided by the Central Weather Bureau (CWB). One major advantage of this method is that we can include out-of-network data to improve the resolution of velocity structures at deeper depths in our study area. The results show that the temporal variations of Vp are less significant than Vs (or Vp/Vs ratio), and Vp is not prominent perturbed before and after the occurrence of the Chi-Chi EQ. However, the Vs (or Vp/Vs ratio) structure in the source area demonstrates significant spatial-temporal difference before and after the mainshock. From the results, before the mainshock, Vs began to decrease (Vp/Vs ratio was increased as well) at the hanging wall of Chelungpu fault, which may be induced by the increasing density of microcracks and fluid. But in the vicinities of Chi-Chi Earthquake's source area, Vs was increasing (Vp/Vs ratio was also decreased). This phenomenon may be owing to the closing of cracks or migration of fluid. Due to the different physical characteristics around the source area, strong earthquake may be easily nucleated at the junctional zone. Our findings suggest that continuously monitoring the Vp and Vs (or

  8. Measuring the seismic velocity in the top 15 km of Earth's inner core

    NARCIS (Netherlands)

    Godwin, Harriet; Waszek, Lauren; Deuss, Arwen

    We present seismic observations of the uppermost layer of the inner core. This was formed most recently, thus its seismic features are related to current solidification processes. Previous studies have only constrained the east-west hemispherical seismic velocity structure in the Earth's inner core

  9. Measuring the seismic velocity in the top 15 km of Earth's inner core

    OpenAIRE

    Godwin, Harriet; Waszek, Lauren; Deuss, Arwen

    2018-01-01

    We present seismic observations of the uppermost layer of the inner core. This was formed most recently, thus its seismic features are related to current solidification processes. Previous studies have only constrained the east-west hemispherical seismic velocity structure in the Earth's inner core at depths greater than 15 km below the inner core boundary. The properties of shallower structure have not yet been determined, because the seismic waves PKIKP and PKiKP used for differential trave...

  10. Excavatability Assessment of Weathered Sedimentary Rock Mass Using Seismic Velocity Method

    International Nuclear Information System (INIS)

    Bin Mohamad, Edy Tonnizam; Noor, Muhazian Md; Isa, Mohamed Fauzi Bin Md.; Mazlan, Ain Naadia; Saad, Rosli

    2010-01-01

    Seismic refraction method is one of the most popular methods in assessing surface excavation. The main objective of the seismic data acquisition is to delineate the subsurface into velocity profiles as different velocity can be correlated to identify different materials. The physical principal used for the determination of excavatability is that seismic waves travel faster through denser material as compared to less consolidated material. In general, a lower velocity indicates material that is soft and a higher velocity indicates more difficult to be excavated. However, a few researchers have noted that seismic velocity method alone does not correlate well with the excavatability of the material. In this study, a seismic velocity method was used in Nusajaya, Johor to assess the accuracy of this seismic velocity method with excavatability of the weathered sedimentary rock mass. A direct ripping run by monitoring the actual production of ripping has been employed at later stage and compared to the ripper manufacturer's recommendation. This paper presents the findings of the seismic velocity tests in weathered sedimentary area. The reliability of using this method with the actual rippability trials is also presented.

  11. Earthquake dynamics. Mapping pressurized volcanic fluids from induced crustal seismic velocity drops.

    Science.gov (United States)

    Brenguier, F; Campillo, M; Takeda, T; Aoki, Y; Shapiro, N M; Briand, X; Emoto, K; Miyake, H

    2014-07-04

    Volcanic eruptions are caused by the release of pressure that has accumulated due to hot volcanic fluids at depth. Here, we show that the extent of the regions affected by pressurized fluids can be imaged through the measurement of their response to transient stress perturbations. We used records of seismic noise from the Japanese Hi-net seismic network to measure the crustal seismic velocity changes below volcanic regions caused by the 2011 moment magnitude (M(w)) 9.0 Tohoku-Oki earthquake. We interpret coseismic crustal seismic velocity reductions as related to the mechanical weakening of the pressurized crust by the dynamic stress associated with the seismic waves. We suggest, therefore, that mapping seismic velocity susceptibility to dynamic stress perturbations can be used for the imaging and characterization of volcanic systems. Copyright © 2014, American Association for the Advancement of Science.

  12. Velocity profiles from borehole seismic in a methane hydrate bearing interval in the eastern Nankai Trough

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K.; Katayama, A.; Yamamoto, H.; Armstrong, P. [Schlumberger, Sagamihara (Japan); Murray, D. [Schlumberger Oilfield Services, Beijing (China); Fukuhara, M. [Schlumberger Moscow Research, Moscow (Russian Federation); Inamori, T.; Saeki, T. [Japan Oil, Gas and Metals National Corp., Chiba (Japan)

    2008-07-01

    In this study, offset vertical seismic profile (OVSP) surveys were conducted to determine seismic velocity profiles for a gas hydrate-bearing interval in the eastern Nankai trough. The survey was used to acquire converted shear waves as well as a 0 offset (ZVSP) survey. The velocity profiles were used to identify and characterize the hydrate deposits in the interval. The study also evaluated the performance of a borehole seismic and sonic measuring tool. An analysis of the OVSP data demonstrated the presence of mode conversion points at the top of the interval as well as at the top and the bottom of a hydrate-concentrated zone. A travel time inversion and parametric inversion process was then used to estimate compressional and shear wave velocities from the shear and direct waves obtained from the ZVSP. Interval velocities from the VSP were then compared with velocities obtained from a sonic log. Results of the comparison indicated that interval velocity profiles increased in the hydrate-bearing zone and decreased at the base of the zone. Seismic and sonic velocities obtained using the tools showed good agreement with each other. However, significant differences were observed in compressional velocities. Velocity discrepancies in the seismic and sonic surveys were attributed to sensitivities related to existing free gas in the area. The borehole seismic tool also acquired additional information in the presence of low saturation gases. It was concluded that a combination of compressional and shear wave data can be used to characterize formation properties. 8 refs., 14 figs.

  13. A randomized clinical trial comparing embryo culture in a conventional incubator with a time-lapse incubator

    DEFF Research Database (Denmark)

    Kirkegaard, Kirstine; Hindkjaer, Johnny Juhl; Grøndahl, Marie Louise

    2012-01-01

    Time-lapse monitoring allows for a flexible embryo evaluation and potentially provides new dynamic markers of embryo competence. Before introducing time-lapse monitoring in a clinical setting, the safety of the instrument must be properly documented. Accordingly, the aim of this study...... was to evaluate the safety of a commercially available time-lapse incubator....

  14. Using micro-seismicity and seismic velocities to map subsurface geologic and hydrologic structure within the Coso geothermal field, California

    Science.gov (United States)

    Kaven, Joern Ole; Hickman, Stephen H.; Davatzes, Nicholas C.

    2012-01-01

    Geothermal reservoirs derive their capacity for fluid and heat transport in large part from faults and fractures. Micro-seismicity generated on such faults and fractures can be used to map larger fault structures as well as secondary fractures that add access to hot rock, fluid storage and recharge capacity necessary to have a sustainable geothermal resource. Additionally, inversion of seismic velocities from micro-seismicity permits imaging of regions subject to the combined effects of fracture density, fluid pressure and steam content, among other factors. We relocate 14 years of seismicity (1996-2009) in the Coso geothermal field using differential travel times and simultaneously invert for seismic velocities to improve our knowledge of the subsurface geologic and hydrologic structure. We utilize over 60,000 micro-seismic events using waveform cross-correlation to augment to expansive catalog of P- and S-wave differential travel times recorded at Coso. We further carry out rigorous uncertainty estimation and find that our results are precise to within 10s of meters of relative location error. We find that relocated micro-seismicity outlines prominent, through-going faults in the reservoir in some cases. We also find that a significant portion of seismicity remains diffuse and does not cluster into more sharply defined major structures. The seismic velocity structure reveals heterogeneous distributions of compressional (Vp) and shear (Vs) wave speed, with Vp generally lower in the main field when compared to the east flank and Vs varying more significantly in the shallow portions of the reservoir. The Vp/Vs ratio appears to outline the two main compartments of the reservoir at depths of -0.5 to 1.5 km (relative to sea-level), with a ridge of relatively high Vp/Vs separating the main field from the east flank. In the deeper portion of the reservoir this ridge is less prominent. Our results indicate that high-precision relocations of micro-seismicity can provide

  15. In-situ measurements of seismic velocities in the San Francisco Bay region...part II

    Science.gov (United States)

    Gibbs, James F.; Fumal, Thomas E.; Borcherdt, Roger D.

    1976-01-01

    Seismic wave velocities (compressional and shear) are important parameters for determining the seismic response characteristics of various geologic units when subjected to strong earthquake ground shaking. Seismic velocities of various units often show a strong correlation with the amounts of damage following large earthquakes and have been used as a basis for certain types of seismic zonation studies. Currently a program is in progress to measure seismic velocities in the San Francisco Bay region at an estimated 150 sites. At each site seismic travel times are measured in drill holes, normally at 2.5-m intervals to a depth of 30 m. Geologic logs are determined from drill hole cuttings, undisturbed samples, and penetrometer samples. The data provide a detailed comparison of geologic and seismic characteristics and provide parameters for estimating strong earthquake ground motions quantitatively at each of the site. A major emphasis of this program is to obtain a detailed comparison of geologic and seismic data on a regional scale for use in seismic zonation. The broad data base available in the San Francisco Bay region suggests using the area as a pilot area for the development of general techniques applicable to other areas.

  16. The relationship of seismic velocity structure and surface fracture characteristics of basalt outcrops to rippability estimates

    International Nuclear Information System (INIS)

    Kay, S.E.; Dougherty, M.E.; Pelton, J.R.

    1994-01-01

    Seismic velocity has been shown in previous engineering studies to be related to the fracture characteristics and rippability of rock outcrops. However, common methods of measuring seismic velocity in outcrops do not take into account the many possible travel paths for wave propagation and the fact that velocity zones may exist within an outcrop. Presented here are the results of using raytracing inversion of first-arrival travel-time data to map P-velocity structure in basalt outcrops, and also the investigation of the relationship of the mapped velocities to observed surface fractures and hand-sample P-velocities. It is shown that basalt outcrops commonly consist of an irregular near-surface low-velocity zone underlain by higher velocity material; that velocity gradients can exist in outcrops; that hand-sample velocity measurements are typically higher than outcrop-scale measurements; and that the characteristics of surface fractures are empirically related to near-surface P-velocity. All of these findings are relevant to the estimated rippability of rock in geotechnical engineering. The data for this study are derived from eleven sites on basalt outcrops of the Troodos Ophiolite in Cyprus. The basalt types include pillow basalts, massive flows, and a pillow breccia. A commonly available raytracing inversion program (RAYINVR) was used to produce a velocity profile of each outcrop. Different velocity zones were detailed by inverting observed travel times to produce a model of outcrop velocity structure which produces rippability profiles for each outcrop. 16 refs., 9 figs

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

    Energy Technology Data Exchange (ETDEWEB)

    Lestari, Titik, E-mail: t2klestari@gmail.com [Meteorological Climatological and Geophysical Agency (MCGA), Jalan Angkasa I No.2 Kemayoran, Jakarta Pusat, 10720 (Indonesia); Faculty of Earth Science and Technology, Bandung Institute of Technology, Jalan Ganesa No.10, Bandung 40132 (Indonesia); Nugraha, Andri Dian, E-mail: nugraha@gf.itb.ac.id [Global Geophysical Research Group, Faculty of Mining and Petroleum Engineering, Bandung Institute of Technology, Jalan Ganesa 10 Bandung 40132 (Indonesia)

    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.

  18. Advances in interpretation of subsurface processes with time-lapse electrical imaging

    Science.gov (United States)

    Singha, Kaminit; Day-Lewis, Frederick D.; Johnson, Tim B.; Slater, Lee D.

    2015-01-01

    Electrical geophysical methods, including electrical resistivity, time-domain induced polarization, and complex resistivity, have become commonly used to image the near subsurface. Here, we outline their utility for time-lapse imaging of hydrological, geochemical, and biogeochemical processes, focusing on new instrumentation, processing, and analysis techniques specific to monitoring. We review data collection procedures, parameters measured, and petrophysical relationships and then outline the state of the science with respect to inversion methodologies, including coupled inversion. We conclude by highlighting recent research focused on innovative applications of time-lapse imaging in hydrology, biology, ecology, and geochemistry, among other areas of interest.

  19. Relative seismic velocity variations correlate with deformation at Kīlauea volcano.

    Science.gov (United States)

    Donaldson, Clare; Caudron, Corentin; Green, Robert G; Thelen, Weston A; White, Robert S

    2017-06-01

    Seismic noise interferometry allows the continuous and real-time measurement of relative seismic velocity through a volcanic edifice. Because seismic velocity is sensitive to the pressurization state of the system, this method is an exciting new monitoring tool at active volcanoes. Despite the potential of this tool, no studies have yet comprehensively compared velocity to other geophysical observables on a short-term time scale at a volcano over a significant length of time. We use volcanic tremor (~0.3 to 1.0 Hz) at Kīlauea as a passive source for interferometry to measure relative velocity changes with time. By cross-correlating the vertical component of day-long seismic records between ~230 station pairs, we extract coherent and temporally consistent coda wave signals with time lags of up to 120 s. Our resulting time series of relative velocity shows a remarkable correlation between relative velocity and the radial tilt record measured at Kīlauea summit, consistently correlating on a time scale of days to weeks for almost the entire study period (June 2011 to November 2015). As the summit continually deforms in deflation-inflation events, the velocity decreases and increases, respectively. Modeling of strain at Kīlauea suggests that, during inflation of the shallow magma reservoir (1 to 2 km below the surface), most of the edifice is dominated by compression-hence closing cracks and producing faster velocities-and vice versa. The excellent correlation between relative velocity and deformation in this study provides an opportunity to understand better the mechanisms causing seismic velocity changes at volcanoes, and therefore realize the potential of passive interferometry as a monitoring tool.

  20. In-situ measurements of seismic velocities in the San Francisco Bay Region; part III

    Science.gov (United States)

    Gibbs, James F.; Fumal, Thomas E.; Borcherdt, Roger D.; Roth, Edward F.

    1977-01-01

    Seismic wave velocities (compressional and shear) are important parameters for estimating the seismic response characteristics of various geologic units when subjected to strong earthquake ground shaking. Seismic velocities of various units often show a strong correlation with the amounts of damage following large earthquakes and have been used as a basis for certain types of seismic zonation studies. In the current program seismic velocities have been measured at 59 locations 1n the San Francisco Bay Region. This report is the third in a series of Open-File Reports and describes the in-situ velocity measurements at locations 35-59. At each location seismic travel times are measured in drill holes, normally at 2.5-m intervals to a depth of 30 m. Geologic logs are determined from drill cuttings, undisturbed (cored) samples, and penetrometer samples. The data provide a detailed comparison of geologic and seismic characteristics and provide parameters for estimating strong earthquake ground motions quantitatively at each of the sites. A major emphasis of this program is to obtain a detailed comparison of geologic and seismic data on a regional scale for use in seismic zonation. There is a variety of geologic and seismic data available in the San Francisco Bay Region for use 1n developing the general zoning techniques which can then be applied to other areas. Shear wave velocities 1n near-surface geologic materials are of especial interest for engineering seismology and seismic zonation studies, yet in general, they are difficult to measure because of contamination by compressional waves. A comparison of various in-situ techniques by Warrick (1974) establishes the reliability of the method utilizing a "horizontal traction" source for sites underlain by bay mud and alluvium. Gibbs, and others (1975a) present data from 12 holes and establishes the reliability of the method for sites underlain by a variety of different rock units and suggest extending the measurements to

  1. Extremal inversion of lunar travel time data. [seismic velocity structure

    Science.gov (United States)

    Burkhard, N.; Jackson, D. D.

    1975-01-01

    The tau method, developed by Bessonova et al. (1974), of inversion of travel times is applied to lunar P-wave travel time data to find limits on the velocity structure of the moon. Tau is the singular solution to the Clairaut equation. Models with low-velocity zones, with low-velocity zones at differing depths, and without low-velocity zones, were found to be consistent with data and within the determined limits. Models with and without a discontinuity at about 25-km depth have been found which agree with all travel time data to within two standard deviations. In other words, the existence of the discontinuity and its size and location have not been uniquely resolved. Models with low-velocity channels are also possible.

  2. Spatial and temporal seismic velocity changes on Kyushu Island during the 2016 Kumamoto earthquake.

    Science.gov (United States)

    Nimiya, Hiro; Ikeda, Tatsunori; Tsuji, Takeshi

    2017-11-01

    Monitoring of earthquake faults and volcanoes contributes to our understanding of their dynamic mechanisms and to our ability to predict future earthquakes and volcanic activity. We report here on spatial and temporal variations of seismic velocity around the seismogenic fault of the 2016 Kumamoto earthquake [moment magnitude ( M w ) 7.0] based on ambient seismic noise. Seismic velocity near the rupture faults and Aso volcano decreased during the earthquake. The velocity reduction near the faults may have been due to formation damage, a change in stress state, and an increase in pore pressure. Further, we mapped the post-earthquake fault-healing process. The largest seismic velocity reduction observed at Aso volcano during the earthquake was likely caused by pressurized volcanic fluids, and the large increase in seismic velocity at the volcano's magma body observed ~3 months after the earthquake may have been a response to depressurization caused by the eruption. This study demonstrates the usefulness of continuous monitoring of faults and volcanoes.

  3. A Low Velocity Zone along the Chaochou Fault in Southern Taiwan: Seismic Image Revealed by a Linear Seismic Array

    Directory of Open Access Journals (Sweden)

    Hsin-Chieh Pu

    2010-01-01

    Full Text Available The Chaochou fault is one of the major boundary faults in southern Taiwan where strong convergence has taken place between the Eurasian and Philippine Sea plates. The surface fault trace between the Pingtung plain and the Central Range follows a nearly N-S direction and stretches to 80 km in length. In order to examine the subsurface structures along the Chaochou fault, a linear seismic array with 14 short-period stations was deployed across the fault to record seismic data between August and December 2001. Detailed examination of seismic data generated by 10 local earthquakes and recorded by the linear array has shown that the incidence angles of the first P-waves recorded by several seismic stations at the fault zone were significantly larger than those located farther away from the fault zone. This difference might reflect the lateral variation of velocity structures across the Chaochou fault. Further examination of ray-paths of seismic wave propagation indicates that a low-velocity zone along the Chaochou fault is needed to explain the significant change in incidence angles across the fault zone. Although we do not have adequate information to calculate the exact geometry of the fault zone well, the variation in incidence angles across the fault can be explained by the existence of a low-velocity zone that is about 3 km in width on the surface and extends downward to a depth of 5 km. The low-velocity zone along the Chaochou fault might imply that the fault system consists of several splay faults on the hanging wall in the Central Range.

  4. A seismic reflection velocity study of a Mississippian mud-mound in the Illinois basin

    Science.gov (United States)

    Ranaweera, Chamila Kumari

    Two mud-mounds have been reported in the Ullin limestone near, but not in, the Aden oil field in Hamilton County, Illinois. One mud-mound is in the Broughton oil field of Hamilton County 25 miles to the south of Aden. The second mud-mound is in the Johnsonville oil field in Wayne County 20 miles to the north of Aden. Seismic reflection profiles were shot in 2012 adjacent to the Aden oil field to evaluate the oil prospects and to investigate the possibility of detecting Mississippian mud-mounds near the Aden field. A feature on one of the seismic profiles was interpreted to be a mud-mound or carbonate buildup. A well drilled at the location of this interpreted structure provided digital geophysical logs and geological logs used to refine the interpretation of the seismic profiles. Geological data from the new well at Aden, in the form of drill cuttings, have been used to essentially confirm the existence of a mud-mound in the Ullin limestone at a depth of 4300 feet. Geophysical well logs from the new well near Aden were used to create 1-D computer models and synthetic seismograms for comparison to the seismic data. The reflection seismic method is widely used to aid interpreting subsurface geology. Processing seismic data is an important step in the method as a properly processed seismic section can give a better image of the subsurface geology whereas a poorly processed section could mislead the interpretation. Seismic reflections will be more accurately depicted with careful determination of seismic velocities and by carefully choosing the processing steps and parameters. Various data processing steps have been applied and parameters refined to produce improved stacked seismic records. The resulting seismic records from the Aden field area indicate a seismic response similar to what is expected from a carbonate mud-mound. One-dimensional synthetic seismograms were created using the available sonic and density logs from the well drilled near the Aden seismic lines

  5. Exploiting the airwave for time-lapse reservoir monitoring with CSEM on land

    NARCIS (Netherlands)

    Wirianto, M.; Mulder, W.A.; Slob, E.C.

    2011-01-01

    In the application of controlled source electromagnetics for reservoir monitoring on land, repeatability errors in the source will mask the time-lapse signal due to hydrocarbon production when recording surface data close to the source. We demonstrate that at larger distances, the airwave will still

  6. Calibrating vadose zone models with time-lapse gravity data: a forced infiltration experiment

    DEFF Research Database (Denmark)

    Christiansen, Lars; Hansen, Allan Bo; Zibar, Majken Caroline Looms

    A change in soil water content is a change in mass stored in the subsurface, and when large enough, can be measured with a gravity meter. Over the last few decades there has been increased use of ground-based time-lapse gravity measurements to infer hydrogeological parameters. These studies have...

  7. Inter and intra-observer variability of time-lapse annotations

    DEFF Research Database (Denmark)

    Sundvall Germeys, Linda Karin M; Ingerslev, Hans Jakob; Knudsen, Ulla Breth

    . This provides the basis for further investigation of embryo assessment and selection by time-lapse imaging in prospective trials. Study funding/competing interest(s): Research at the Fertility Clinic was funded by an unrestricted grant from Ferring and MSD. The authors have no competing interests to declare....

  8. Entropy-Bayesian Inversion of Time-Lapse Tomographic GPR data for Monitoring Dielectric Permittivity and Soil Moisture Variations

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Z; Terry, N; Hubbard, S S; Csatho, B

    2013-02-12

    In this study, we evaluate the possibility of monitoring soil moisture variation using tomographic ground penetrating radar travel time data through Bayesian inversion, which is integrated with entropy memory function and pilot point concepts, as well as efficient sampling approaches. It is critical to accurately estimate soil moisture content and variations in vadose zone studies. Many studies have illustrated the promise and value of GPR tomographic data for estimating soil moisture and associated changes, however, challenges still exist in the inversion of GPR tomographic data in a manner that quantifies input and predictive uncertainty, incorporates multiple data types, handles non-uniqueness and nonlinearity, and honors time-lapse tomograms collected in a series. To address these challenges, we develop a minimum relative entropy (MRE)-Bayesian based inverse modeling framework that non-subjectively defines prior probabilities, incorporates information from multiple sources, and quantifies uncertainty. The framework enables us to estimate dielectric permittivity at pilot point locations distributed within the tomogram, as well as the spatial correlation range. In the inversion framework, MRE is first used to derive prior probability distribution functions (pdfs) of dielectric permittivity based on prior information obtained from a straight-ray GPR inversion. The probability distributions are then sampled using a Quasi-Monte Carlo (QMC) approach, and the sample sets provide inputs to a sequential Gaussian simulation (SGSim) algorithm that constructs a highly resolved permittivity/velocity field for evaluation with a curved-ray GPR forward model. The likelihood functions are computed as a function of misfits, and posterior pdfs are constructed using a Gaussian kernel. Inversion of subsequent time-lapse datasets combines the Bayesian estimates from the previous inversion (as a memory function) with new data. The memory function and pilot point design takes

  9. Entropy-Bayesian Inversion of Time-Lapse Tomographic GPR data for Monitoring Dielectric Permittivity and Soil Moisture Variations

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Zhangshuan; Terry, Neil C.; Hubbard, Susan S.

    2013-02-22

    In this study, we evaluate the possibility of monitoring soil moisture variation using tomographic ground penetrating radar travel time data through Bayesian inversion, which is integrated with entropy memory function and pilot point concepts, as well as efficient sampling approaches. It is critical to accurately estimate soil moisture content and variations in vadose zone studies. Many studies have illustrated the promise and value of GPR tomographic data for estimating soil moisture and associated changes, however, challenges still exist in the inversion of GPR tomographic data in a manner that quantifies input and predictive uncertainty, incorporates multiple data types, handles non-uniqueness and nonlinearity, and honors time-lapse tomograms collected in a series. To address these challenges, we develop a minimum relative entropy (MRE)-Bayesian based inverse modeling framework that non-subjectively defines prior probabilities, incorporates information from multiple sources, and quantifies uncertainty. The framework enables us to estimate dielectric permittivity at pilot point locations distributed within the tomogram, as well as the spatial correlation range. In the inversion framework, MRE is first used to derive prior probability density functions (pdfs) of dielectric permittivity based on prior information obtained from a straight-ray GPR inversion. The probability distributions are then sampled using a Quasi-Monte Carlo (QMC) approach, and the sample sets provide inputs to a sequential Gaussian simulation (SGSIM) algorithm that constructs a highly resolved permittivity/velocity field for evaluation with a curved-ray GPR forward model. The likelihood functions are computed as a function of misfits, and posterior pdfs are constructed using a Gaussian kernel. Inversion of subsequent time-lapse datasets combines the Bayesian estimates from the previous inversion (as a memory function) with new data. The memory function and pilot point design takes advantage of

  10. Relating seismicity to the velocity structure of the San Andreas Fault near Parkfield, CA

    Science.gov (United States)

    Lippoldt, Rachel; Porritt, Robert W.; Sammis, Charles G.

    2017-06-01

    The central section of the San Andreas Fault (SAF) displays a range of seismic phenomena including normal earthquakes, low-frequency earthquakes (LFE), repeating microearthquakes (REQ) and aseismic creep. Although many lines of evidence suggest that LFEs are tied to the presence of fluids, their geological setting is still poorly understood. Here, we map the seismic velocity structures associated with LFEs beneath the central SAF using surface wave tomography from ambient seismic noise to provide constraints on the physical conditions that control LFE occurrence. Fault perpendicular sections show that the SAF, as revealed by lateral contrasts in relative velocities, is contiguous to depths of 50 km and appears to be relatively localized at depths between about 15 and 30 km. This is consistent with the hypothesis that LFEs are shear-slip events on a deep extension of the SAF. We find that along strike variations in seismic behaviour correspond to changes in the seismic structure, which support proposed connections between fluids and seismicity. LFEs and REQs occur within low-velocity structures, suggesting that the presence of fluids, weaker minerals, or hydrous phase minerals may play an important role in the generation of slow-slip phenomena.

  11. Seismic velocity structure in the lower crust beneath the seismic belt in the San-in district, Southwest Japan

    Science.gov (United States)

    Tsuda, H.; Iio, Y.; Shibutani, T.

    2017-12-01

    In the San-in district in Southwest Japan, a linear distribution of the epicenters of microearthquakes is seen along the coast of the Japan Sea (Fig. 1). The linear distribution is known as the seismic belt in the San-in district. Large earthquakes also occurred in the seismic belt. What localizes the earthquake distribution in the San-in district which is located far from the plate boundary? We thought that the model proposed by Iio et al. (2002, 2004) could answer this question. The model is as follows. Viscosity is low in a part of the lower crust, which is called `weak zone'. Stress and strain are concentrated in the upper crust right above the weak zone, due to concentrated deformation in the weak zone, and thus earthquakes occur there. To verify whether the weak zone exists in the lower crust beneath the seismic belt, we estimated the seismic velocity structure there by travel-time tomography. We used the tomography program, FMTOMO (Rawlinson et al., 2006). For the model space, we set the latitude range of 33°-36°N, the longitude range of 131°-136°E (Fig. 1), and the depth range of 0-81 km. The grid intervals are 0.1°×0.1°×7 km. We used arrival times picked by Japan Meteorological Agency (JMA) for earthquakes that occurred in the study area. In addition, we used arrival times manually picked at stations in and around the San-in district for earthquakes that occurred within the Philippine Sea Slab, because they are not included in the JMA data. Since the seismic waves from those earthquakes to the stations in the San-in district pass through the lower crust beneath the San-in district, we expect that these data can improve the resolution there. We revealed that low velocity anomalies exist in the lower crust beneath the seismic belt (Fig. 1). It is inferred that the region of low velocity anomalies is characterized by low viscosity, since velocities of rocks decrease with temperature and/or water content. Therefore, the results of this study support

  12. Variations and healing of the seismic velocity (Beno Gutenberg Medal Lecture)

    Science.gov (United States)

    Snieder, Roel

    2016-04-01

    Scattering of waves leads to a complexity of waveforms that is often seen by seismologists as a nuisance. And indeed, the complicated wave paths of multiple scattered waves makes it difficult to use these waves for imaging. Yet, the long wave paths of multiple scattered waves makes these waves an ideal tool for measuring minute velocity changes. This has led to the development of coda wave interferometry as a tool for measuring small velocity changes in the laboratory and with field data. Combined with the use of noise cross correlations - seismic interferometry - this method is even more useful because it follows for a quasi-continuous measurement of velocity changes. I will show examples of detecting velocity changes in the laboratory, the earth's near surface, and in engineered structures. Perhaps surprisingly, the seismic velocity is not constant at all, and varies with the seasons, temperature, precipitation, as the weather does. In addition, the seismic velocity usually drops as a result of deformation. Most of these changes likely occur in the near surface or the region of deformation, and a drawback of using strongly scattered waves is that it is difficult to localize the spatial area of the velocity change. I will present laboratory measurements that show that a certain spatial localization of the velocity change can be achieved. One of the intriguing observations is that after deformation the seismic velocity recovers logarithmically with time. The reason for this particular time-dependence is the presence of healing mechanisms that operate at different time scales. Since this is feature of many physical systems, the logarithmic healing is a widespread behavior and is akin in its generality to the Gutenberg-Richter law.

  13. Coupled hydrogeophysical inversion using time-lapse magnetic resonance sounding and time-lapse gravity data for hydraulic aquifer testing: Will it work in practice?

    DEFF Research Database (Denmark)

    Herckenrath, Daan; Auken, Esben; Christiansen, Lars

    2012-01-01

    Temporal changes in water content can be directly related to the time-lapse signals retrieved using magnetic resonance sounding (TL-MRS) and relative gravimetry (TL-RG). Previous studies suggest that TL-RG measurements can potentially provide accurate estimates of aquifer characteristics in an aq......Temporal changes in water content can be directly related to the time-lapse signals retrieved using magnetic resonance sounding (TL-MRS) and relative gravimetry (TL-RG). Previous studies suggest that TL-RG measurements can potentially provide accurate estimates of aquifer characteristics...... in an aquifer pumping test experiment when used in a coupled hydrogeophysical inversion approach. However, these studies considered highly idealized conditions. The aim of this paper is twofold: first, we investigate three major issues which likely limit the practical utility of TL-RG for pumping test...... monitoring: partially penetrating pumping wells in anisotropic aquifers, delayed drainage effects, and typical data errors for TL-RG. Second, we introduce TL-MRS in a similar coupled hydrogeophysical inversion framework and compare the performance of TL-MRS and TL-RG for pumping test monitoring...

  14. Near-Surface Seismic Velocity Data: A Computer Program For ...

    African Journals Online (AJOL)

    A computer program (NESURVELANA) has been developed in Visual Basic Computer programming language to carry out a near surface velocity analysis. The method of analysis used includes: Algorithms design and Visual Basic codes generation for plotting arrival time (ms) against geophone depth (m) employing the ...

  15. A bayesian approach for determining velocity and uncertainty estimates from seismic cone penetrometer testing or vertical seismic profiling data

    Science.gov (United States)

    Pidlisecky, Adam; Haines, S.S.

    2011-01-01

    Conventional processing methods for seismic cone penetrometer data present several shortcomings, most notably the absence of a robust velocity model uncertainty estimate. We propose a new seismic cone penetrometer testing (SCPT) data-processing approach that employs Bayesian methods to map measured data errors into quantitative estimates of model uncertainty. We first calculate travel-time differences for all permutations of seismic trace pairs. That is, we cross-correlate each trace at each measurement location with every trace at every other measurement location to determine travel-time differences that are not biased by the choice of any particular reference trace and to thoroughly characterize data error. We calculate a forward operator that accounts for the different ray paths for each measurement location, including refraction at layer boundaries. We then use a Bayesian inversion scheme to obtain the most likely slowness (the reciprocal of velocity) and a distribution of probable slowness values for each model layer. The result is a velocity model that is based on correct ray paths, with uncertainty bounds that are based on the data error. ?? NRC Research Press 2011.

  16. Measuring the seismic velocity in the top 15 km of Earth's inner core

    Science.gov (United States)

    Godwin, Harriet; Waszek, Lauren; Deuss, Arwen

    2018-01-01

    We present seismic observations of the uppermost layer of the inner core. This was formed most recently, thus its seismic features are related to current solidification processes. Previous studies have only constrained the east-west hemispherical seismic velocity structure in the Earth's inner core at depths greater than 15 km below the inner core boundary. The properties of shallower structure have not yet been determined, because the seismic waves PKIKP and PKiKP used for differential travel time analysis arrive close together and start to interfere. Here, we present a method to make differential travel time measurements for waves that turn in the top 15 km of the inner core, and measure the corresponding seismic velocity anomalies. We achieve this by generating synthetic seismograms to model the overlapping signals of the inner core phase PKIKP and the inner core boundary phase PKiKP. We then use a waveform comparison to attribute different parts of the signal to each phase. By measuring the same parts of the signal in both observed and synthetic data, we are able to calculate differential travel time residuals. We apply our method to data with ray paths which traverse the Pacific hemisphere boundary. We generate a velocity model for this region, finding lower velocity for deeper, more easterly ray paths. Forward modelling suggests that this region contains either a high velocity upper layer, or variation in the location of the hemisphere boundary with depth and/or latitude. Our study presents the first direct seismic observation of the uppermost 15 km of the inner core, opening new possibilities for further investigating the inner core boundary region.

  17. A randomized clinical trial comparing embryo culture in a conventional incubator with a time-lapse incubator

    DEFF Research Database (Denmark)

    Kirkegaard, Kirstine; Hindkjaer, Johnny Juhl; Grøndahl, Marie Louise

    2012-01-01

    Time-lapse monitoring allows for a flexible embryo evaluation and potentially provides new dynamic markers of embryo competence. Before introducing time-lapse monitoring in a clinical setting, the safety of the instrument must be properly documented. Accordingly, the aim of this study was to eval...

  18. A generalized formulation for noise-based seismic velocity change measurements

    Science.gov (United States)

    Gómez-García, C.; Brenguier, F.; Boué, P.; Shapiro, N.; Droznin, D.; Droznina, S.; Senyukov, S.; Gordeev, E.

    2017-12-01

    The observation of continuous seismic velocity changes is a powerful tool for detecting seasonal variations in crustal structure, volcanic unrest, co- and post-seismic evolution of stress in fault areas or the effects of fluid injection. The standard approach for measuring such velocity changes relies on comparison of travel times in the coda of a set of seismic signals, usually noise-based cross-correlations retrieved at different dates, and a reference trace, usually a averaged function over dates. A good stability in both space and time of the noise sources is then the main assumption for reliable measurements. Unfortunately, these conditions are often not fulfilled, as it happens when ambient-noise sources are non-stationary, such as the emissions of low-frequency volcanic tremors.We propose a generalized formulation for retrieving continuous time series of noise-based seismic velocity changes without any arbitrary reference cross-correlation function. We set up a general framework for future applications of this technique performing synthetic tests. In particular, we study the reliability of the retrieved velocity changes in case of seasonal-type trends, transient effects (similar to those produced as a result of an earthquake or a volcanic eruption) and sudden velocity drops and recoveries as the effects of transient local source emissions. Finally, we apply this approach to a real dataset of noise cross-correlations. We choose the Klyuchevskoy volcanic group (Kamchatka) as a case study where the recorded wavefield is hampered by loss of data and dominated by strongly localized volcanic tremor sources. Despite the mentioned wavefield contaminations, we retrieve clear seismic velocity drops associated with the eruptions of the Klyuchevskoy an the Tolbachik volcanoes in 2010 and 2012, respectively.

  19. Constraining seismic velocity features combining short and long period signals: Test ground is Turkey

    Science.gov (United States)

    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. Allowable Pressure In Soils and Rocks by Seismic Wave Velocities

    International Nuclear Information System (INIS)

    Tezcan, S.; Keceli, A.; Oezdemir, Z.

    2007-01-01

    Firstly, the historical background is presented for the determination of ultimate bearing capacity of shallow foundations. The principles of plastic equilibrium used in the classical formulation of the ultimate bearing capacity are reviewed, followed by a discussion about the sources of approximations inherent in the classical theory. Secondly, based on a variety of case histories of site investigations, including extensive bore hole data, laboratory testing and geophysical prospecting, an empirical formulation is proposed for the determination of allowable bearing capacity of shallow foundations. The proposed expression corroborates consistently with the results of the classical theory and is proven to be reliable and safe, also from the view point of maximum allowable settlements. It consists of only two soil parameters, namely, the Institut measured shear wave velocity, and the unit weight. The unit weight may be also determined with sufficient accuracy, by means of another empirical expression, using the P-wave velocity. It is indicated that once the shear and P-wave velocities are measured Institut by an appropriate geophysical survey, the allowable bearing capacity is determined reliably through a single step operation. Such an approach, is considerably cost and time-saving, in practice

  1. 1-D seismic velocity model and hypocenter relocation using double difference method around West Papua region

    Science.gov (United States)

    Sabtaji, Agung; Nugraha, Andri Dian

    2015-04-01

    West Papua region has fairly high of seismicity activities due to tectonic setting and many inland faults. In addition, the region has a unique and complex tectonic conditions and this situation lead to high potency of seismic hazard in the region. The precise earthquake hypocenter location is very important, which could provide high quality of earthquake parameter information and the subsurface structure in this region to the society. We conducted 1-D P-wave velocity using earthquake data catalog from BMKG for April, 2009 up to March, 2014 around West Papua region. The obtained 1-D seismic velocity then was used as input for improving hypocenter location using double-difference method. The relocated hypocenter location shows fairly clearly the pattern of intraslab earthquake beneath New Guinea Trench (NGT). The relocated hypocenters related to the inland fault are also observed more focus in location around the fault.

  2. 1-D seismic velocity model and hypocenter relocation using double difference method around West Papua region

    Energy Technology Data Exchange (ETDEWEB)

    Sabtaji, Agung, E-mail: sabtaji.agung@gmail.com, E-mail: agung.sabtaji@bmkg.go.id [Study Program of Earth Sciences, Faculty of Earth Sciencies and Technology, Institute of Technology Bandung, Bandung 40132 (Indonesia); Indonesia’s Agency for Meteorological, Climatological and Geophysics Region V, Jayapura 1572 (Indonesia); Nugraha, Andri Dian, E-mail: nugraha@gf.itb.ac.id [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Bandung 40132 (Indonesia)

    2015-04-24

    West Papua region has fairly high of seismicity activities due to tectonic setting and many inland faults. In addition, the region has a unique and complex tectonic conditions and this situation lead to high potency of seismic hazard in the region. The precise earthquake hypocenter location is very important, which could provide high quality of earthquake parameter information and the subsurface structure in this region to the society. We conducted 1-D P-wave velocity using earthquake data catalog from BMKG for April, 2009 up to March, 2014 around West Papua region. The obtained 1-D seismic velocity then was used as input for improving hypocenter location using double-difference method. The relocated hypocenter location shows fairly clearly the pattern of intraslab earthquake beneath New Guinea Trench (NGT). The relocated hypocenters related to the inland fault are also observed more focus in location around the fault.

  3. Hydrocarbon Reservoir Parameter Estimation Using Production Data and Time-Lapse Seismic

    NARCIS (Netherlands)

    Przybysz-Jarnut, J.K.

    2010-01-01

    The numerical simulation of hydrocarbon reservoir flow is necessarily an approximation of the flow in the real reservoir. The knowledge about the reservoir is limited and some of the processes occurring are either not taken into account or not described in an adequate way. The parameters influencing

  4. Effect of oxygen concentration on human embryo development evaluated by time-lapse monitoring

    DEFF Research Database (Denmark)

    Ingerslev, Hans Jakob; Hindkjær, Johnny Juhl; Kirkegaard, Kirstine

    2012-01-01

    -points for each cell division and blastocyst stages were registered until 120 hours after oocyte retrieval. Only 2PN embryos completing the first cleavage were evaluated. The groups were compared using one-way ANOVA or Kruskall-Wallis test. Estimates are reported as medians with 95% confidence intervals. Time......Introduction: Data from a number of studies indicate -but not unequivocally- that culture of embryos in 5% O2 compared to 20% O2 improves blastocyst formation in humans and various animal species and may yield better pregnancy rates in IVF. The detrimental effects of atmospheric oxygen were...... was to evaluate the influence of oxygen tension on human pre-implantation development using time-lapse monitoring. Materials and methods: Human embryos were cultured to the blastocyst stage in a time-lapse incubator (EmbryoScope™) in 20% O2 (group 1), 20% O2 for 24 hours followed by culture in 5% O2 (group 2...

  5. Freeze core sampling to validate time-lapse resistivity monitoring of the hyporheic zone.

    Science.gov (United States)

    Toran, Laura; Hughes, Brian; Nyquist, Jonathan; Ryan, Robert

    2013-01-01

    A freeze core sampler was used to characterize hyporheic zone storage during a stream tracer test. The pore water from the frozen core showed tracer lingered in the hyporheic zone after the tracer had returned to background concentration in collocated well samples. These results confirmed evidence of lingering subsurface tracer seen in time-lapse electrical resistivity tomographs. The pore water exhibited brine exclusion (ion concentrations in ice lower than source water) in a sediment matrix, despite the fast freezing time. Although freeze core sampling provided qualitative evidence of lingering tracer, it proved difficult to quantify tracer concentration because the amount of brine exclusion during freezing could not be accurately determined. Nonetheless, the additional evidence for lingering tracer supports using time-lapse resistivity to detect regions of low fluid mobility within the hyporheic zone that can act as chemically reactive zones of importance in stream health. © 2012, The Author(s). GroundWater © 2012, National Ground Water Association.

  6. Capturing tissue repair in zebrafish larvae with time-lapse brightfield stereomicroscopy.

    Science.gov (United States)

    Lisse, Thomas S; Brochu, Elizabeth A; Rieger, Sandra

    2015-01-31

    The zebrafish larval tail fin is ideal for studying tissue regeneration due to the simple architecture of the larval fin-fold, which comprises of two layers of skin that enclose undifferentiated mesenchyme, and because the larval tail fin regenerates rapidly within 2-3 days. Using this system, we demonstrate a method for capturing the repair dynamics of the amputated tail fin with time-lapse video brightfield stereomicroscopy. We demonstrate that fin amputation triggers a contraction of the amputation wound and extrusion of cells around the wound margin, leading to their subsequent clearance. Fin regeneration proceeds from proximal to distal direction after a short delay. In addition, developmental growth of the larva can be observed during all stages. The presented method provides an opportunity for observing and analyzing whole tissue-scale behaviors such as fin development and growth in a simple microscope setting, which is easily adaptable to any stereomicroscope with time-lapse capabilities.

  7. Time-lapse electrical surveys to locate infiltration zones in weathered hard rock tropical areas

    Science.gov (United States)

    Wubda, M.; Descloitres, M.; Yalo, N.; Ribolzi, O.; Vouillamoz, J. M.; Boukari, M.; Hector, B.; Séguis, L.

    2017-07-01

    In West Africa, infiltration and groundwater recharge processes in hard rock areas are depending on climatic, surface and subsurface conditions, and are poorly documented. Part of the reason is that identification, location and monitoring of these processes is still a challenge. Here, we explore the potential for time-lapse electrical surveys to bring additional information on these processes for two different climate situations: a semi-arid Sahelian site (north of Burkina and a humid Sudanian site (north of Benin), respectively focusing on indirect (localized) and direct (diffuse) recharge processes. The methodology is based on surveys in dry season and rainy season on typical pond or gully using Electrical Resistivity Tomography (ERT) and frequency electromagnetic (FEM) apparent conductivity mapping. The results show that in the Sahelian zone an indirect recharge occurs as expected, but infiltration doesn't takes place at the center of the pond to the aquifer, but occurs laterally in the banks. In Sudanian zone, the ERT survey shows a direct recharge process as expected, but also a complicated behavior of groundwater dilution, as well as the role of hardpans for fast infiltration. These processes are ascertained by groundwater monitoring in adjacent observing wells. At last, FEM time lapse mapping is found to be difficult to quantitatively interpreted due to the non-uniqueness of the model, clearly evidenced comparing FEM result to auger holes monitoring. Finally, we found that time-lapse ERT can be an efficient way to track infiltration processes across ponds and gullies in both climatic conditions, the Sahelian setting providing results easier to interpret, due to significant resistivity contrasts between dry and rain seasons. Both methods can be used for efficient implementation of punctual sensors for complementary studies. However, FEM time-lapse mapping remains difficult to practice without external information that renders this method less attractive for

  8. Calixarenes and cations: a time-lapse photography of the big-bang.

    Science.gov (United States)

    Casnati, Alessandro

    2013-08-07

    The outstanding cation complexation properties emerging from the pioneering studies on calixarene ligands during a five-year period in the early 1980s triggered a big-bang burst of publications on such macrocycles that is still lasting at a distance of more than 30 years. A time-lapse photography of this timeframe is proposed which allows the readers to pinpoint the contributions of the different research groups.

  9. 3D Time-lapse Imaging and Quantification of Mitochondrial Dynamics

    OpenAIRE

    Sison, Miguel; Chakrabortty, Sabyasachi; Extermann, J?r?me; Nahas, Amir; James Marchand, Paul; Lopez, Antonio; Weil, Tanja; Lasser, Theo

    2017-01-01

    We present a 3D time-lapse imaging method for monitoring mitochondrial dynamics in living HeLa cells based on photothermal optical coherence microscopy and using novel surface functionalization of gold nanoparticles. The biocompatible protein-based biopolymer coating contains multiple functional groups which impart better cellular uptake and mitochondria targeting efficiency. The high stability of the gold nanoparticles allows continuous imaging over an extended time up to 3000 seconds withou...

  10. Automated Tracking of Root for Confocal Time-lapse Imaging of Cellular Processes

    OpenAIRE

    Doumane, Mehdi; Lionnet, Claire; Bayle, Vincent; Jaillais, Yvon; Caillaud, Marie-C?cile

    2017-01-01

    Here we describe a protocol that enables to automatically perform time-lapse imaging of growing root tips for several hours. Plants roots expressing fluorescent proteins or stained with dyes are imaged while they grow using automatic movement of the microscope stage that compensates for root growth and allows to follow a given region of the root over time. The protocol makes possible the image acquisition of multiple growing root tips, therefore increasing the number of recorded mitotic event...

  11. Probabilistic 3-D time-lapse inversion of magnetotelluric data: Application to an enhanced geothermal system

    Science.gov (United States)

    Rosas-Carbajal, Marina; Linde, Nicolas; Peacock, Jared R.; Zyserman, F. I.; Kalscheuer, Thomas; Thiel, Stephan

    2015-01-01

    Surface-based monitoring of mass transfer caused by injections and extractions in deep boreholes is crucial to maximize oil, gas and geothermal production. Inductive electromagnetic methods, such as magnetotellurics, are appealing for these applications due to their large penetration depths and sensitivity to changes in fluid conductivity and fracture connectivity. In this work, we propose a 3-D Markov chain Monte Carlo inversion of time-lapse magnetotelluric data to image mass transfer following a saline fluid injection. The inversion estimates the posterior probability density function of the resulting plume, and thereby quantifies model uncertainty. To decrease computation times, we base the parametrization on a reduced Legendre moment decomposition of the plume. A synthetic test shows that our methodology is effective when the electrical resistivity structure prior to the injection is well known. The centre of mass and spread of the plume are well retrieved.We then apply our inversion strategy to an injection experiment in an enhanced geothermal system at Paralana, South Australia, and compare it to a 3-D deterministic time-lapse inversion. The latter retrieves resistivity changes that are more shallow than the actual injection interval, whereas the probabilistic inversion retrieves plumes that are located at the correct depths and oriented in a preferential north-south direction. To explain the time-lapse data, the inversion requires unrealistically large resistivity changes with respect to the base model. We suggest that this is partly explained by unaccounted subsurface heterogeneities in the base model from which time-lapse changes are inferred.

  12. Assessment of Time-Lapse in Visible and Thermal Face Recognition

    Czech Academy of Sciences Publication Activity Database

    Farokhi, Sajad; Shamsuddin, Siti Mariyam; Flusser, Jan; Sheikh, Usman Ullah

    2012-01-01

    Roč. 6, č. 1 (2012), s. 181-186 R&D Projects: GA ČR GAP103/11/1552 Institutional support: RVO:67985556 Keywords : face recognition * moment invariants * Zernike moments Subject RIV: JD - Computer Applications, Robotics http://library.utia.cas.cz/separaty/2012/ZOI/flusser-assessment of time-lapse in visible and thermal face recognition -j.pdf

  13. Heat-flow and lateral seismic-velocity heterogeneities near Deep Sea Drilling Project-Ocean Drilling Program Site 504

    Science.gov (United States)

    Lowell, Robert P.; Stephen, Ralph A.

    1991-11-01

    Both conductive heat-flow and seismic-velocity data contain information relating to the permeability of the oceanic crust. Deep Sea Drilling Project-Ocean Drilling Program Site 504 is the only place where both detailed heat-flow and seismic-velocity field studies have been conducted at the same scale. In this paper we examine the correlation between heat flow and lateral heterogeneities in seismic velocity near Site 504. Observed heterogeneities in seismic velocity, which are thought to be related to variations in crack density in the upper 500 m of the basaltic crust, show little correlation with the heat-flow pattern. This lack of correlation highlights some of the current difficulties in using seismic-velocity data to infer details of spatial variations in permeability that are significant in controlling hydrothermal circulation.

  14. InSight detection of a Lithospheric Low Seismic Velocity Zone in Mars

    Science.gov (United States)

    Zheng, Y.; Nimmo, F.; Lay, T.

    2014-12-01

    Most seismological models for the interior of Mars lack an upper mantle low velocity zone. However, there is expected to be a large thermal gradient across the stagnant conductive lid (lithosphere) of Mars. This gradient should tend to decrease elastic wave velocities with increasing depth, with this effect dominating the opposing tendency caused by increasing pressure with depth because Mars has low gravity. An upper mantle lithosphere with a low velocity zone (LVZ) beneath a thin high velocity "seismic lid" is thus predicted. The upcoming NASA InSight mission includes a three-component seismometer, which should provide the first opportunity to directly detect any lithospheric LVZ in Mars. Seismic wavefields expected for Mars mantle velocity structures with or without a strong LVZ are very distinct and may be distinguished by observing a modest number of seismic sources at different epicentral ranges. The LVZ models predict shadow zones for high-frequency seismic body wave phases such as P, S, PP and SS, etc. The most diagnostic waves that can be used to evaluate presence of a lithospheric LVZ given a single seismometer are intermediate period surface waves, which travel along the great circle from a seismic source to the seismometer along both minor- and (if the source is large enough) major-arc directions. An LVZ produces distinctive dispersion, with a Rayleigh wave Airy phase around 100 s period and very different surface wave seismograms compared to a model with no LVZ. Even a single observation of long-period surface waves from a known range can be diagnostic of the lithospheric structure. Establishing the existence of an LVZ has major implications for thermal evolution, volatile content and internal dynamics of the planet.

  15. Using time-lapse gravity for groundwater model calibration: An application to alluvial aquifer storage

    DEFF Research Database (Denmark)

    Christiansen, Lars; Binning, Philip John; Rosbjerg, Dan

    2011-01-01

    The estimation of hydrological model parameters by calibration to field data is a critical step in the modeling process. However, calibration often fails because of parameter correlation. Here it is shown that time-lapse gravity data can be combined with hydraulic head data in a coupled hydrogeop......The estimation of hydrological model parameters by calibration to field data is a critical step in the modeling process. However, calibration often fails because of parameter correlation. Here it is shown that time-lapse gravity data can be combined with hydraulic head data in a coupled...... shows that time-lapse gravity data are especially useful to constrain specific yield. Furthermore, we demonstrate that evapotranspiration, and riverbed conductance are better constrained by coupled inversion to gravity and head data than to head data alone. When estimating the four parameters...... simultaneously, the six correlation coefficients were reduced from unity when only head data were employed to significantly lower values when gravity and head data were combined. Our analysis reveals that the estimated parameter values are not very sensitive to the choice of weighting between head and gravity...

  16. Efficiency of time-lapse intervals and simple baits for camera surveys of wild pigs

    Science.gov (United States)

    Williams, B.L.; Holtfreter, R.W.; Ditchkoff, S.S.; Grand, J.B.

    2011-01-01

    Growing concerns surrounding established and expanding populations of wild pigs (Sus scrofa) have created the need for rapid and accurate surveys of these populations. We conducted surveys of a portion of the wild pig population on Fort Benning, Georgia, to determine if a longer time-lapse interval than had been previously used in surveys of wild pigs would generate similar detection results. We concurrently examined whether use of soured corn at camera sites affected the time necessary for pigs to locate a new camera site or the time pigs remained at a site. Our results suggest that a 9-min time-lapse interval generated dependable detection results for pigs and that soured corn neither attracted pigs to a site any quicker than plain, dry, whole-kernel corn, nor held them at a site longer. Maximization of time-lapse interval should decrease data and processing loads, and use of a simple, available bait should decrease cost and effort associated with more complicated baits; combination of these concepts should increase efficiency of wild pig surveys. ?? 2011 The Wildlife Society.

  17. High resolution Rayleigh wave group velocity tomography in North-China from ambient seismic noise

    International Nuclear Information System (INIS)

    Fang Lihua; Wu Jianping; Ding Zhifeng; Panza, G.F.

    2009-03-01

    This study presents the results of the Rayleigh wave group velocity tomography in North-China performed using ambient seismic noise observed at 190 broadband and 10 very broadband stations of the North-China Seismic Array. All available vertical component time-series for the 14 months span between January, 2007 and February, 2008 are cross-correlated to obtain empirical Rayleigh wave Green functions that are subsequently processed, with the multiple filter method, to isolate the group velocity dispersion curves of the fundamental mode of Rayleigh wave. Tomographic maps, with a grid spacing of 0.25 deg. x 0.25 deg., are computed at the periods of 4.5s, 12s, 20s, 28s. The maps at short periods reveal an evident lateral heterogeneity in the crust of North-China, quite well in agreement with known geological and tectonic features. The North China Basin is imaged as a broad low velocity area, while the Taihangshan and Yanshan uplifts and Ordos block are imaged as high velocity zones, and the Quaternary intermountain basins show up as small low-velocity anomalies. The group velocity contours at 4.5s, 12s and 20s are consistent with the Bouguer gravity anomalies measured in the area of the Taihangshan fault, that cuts through the lower crust at least. Most of the historical strong earthquakes (M≥6.0) are located where the tomographic maps show zones with moderate velocity gradient. (author)

  18. Building Subsurface Velocity Models with Sharp Interfaces Using Interface-Guided Seismic Full-Waveform Inversion

    Science.gov (United States)

    Lin, Youzuo; Huang, Lianjie

    2017-11-01

    Reverse-time migration has the potential to image complex subsurface structures, including steeply-dipping fault zones, but the method requires an accurate velocity model. Acoustic- and elastic-waveform inversion is a promising tool for high-resolution velocity model building. Because of the ill-posedness of acoustic- and elastic-waveform inversion, it is a great challenge to obtain accurate velocity models containing sharp interfaces. To improve velocity model building, we develop an acoustic- and elastic-waveform inversion method with an interface-guided modified total-variation regularization scheme to improve the inversion accuracy and robustness, particularly for models with sharp interfaces and steeply-dipping fault zones with widths much smaller than the seismic wavelength. The new regularization scheme incorporates interface information into seismic full-waveform inversion. The interface information of subsurface interfaces is obtained iteratively using migration imaging during waveform inversion. Seismic migration is robust for subsurface imaging. Our new acoustic- and elastic-waveform inversion takes advantage of the robustness of migration imaging to improve velocity estimation. We use synthetic seismic data for a complex model containing sharp interfaces and several steeply-dipping fault zones to validate the improved capability of our new acoustic- and elastic-waveform inversion method. Our inversion results are much better than those produced without using interface-guided regularization. Acoustic- and elastic-waveform inversion with an interface-guided modified total-variation regularization scheme has the potential to accurately build subsurface velocity models with sharp interfaces and/or steep fault zones.

  19. Shear wave velocity versus quality factor: results from seismic noise recordings

    Science.gov (United States)

    Boxberger, Tobias; Pilz, Marco; Parolai, Stefano

    2017-08-01

    The assessment of the shear wave velocity (vs) and shear wave quality factor (Qs) for the shallow structure below a site is necessary to characterize its site response. In the past, methods based on the analysis of seismic noise have been shown to be very efficient for providing a sufficiently accurate estimation of the vs versus depth at reasonable costs for engineering seismology purposes. In addition, a slight modification of the same method has proved to be able to provide realistic Qs versus depth estimates. In this study, data sets of seismic noise recorded by microarrays of seismic stations in different geological environments of Europe and Central Asia are used to calculate both vs and Qs versus depth profiles. Analogous to the generally adopted approach in seismic hazard assessment for mapping the average shear wave velocity in the uppermost 30 m (vs30) as a proxy of the site response, this approach was also applied to the quality factor within the uppermost 30 m (Qs30). A slightly inverse correlation between both parameters is found based on a methodological consistent determination for different sites. Consequently, a combined assessment of vs and Qs by seismic noise analysis has the potential to provide a more comprehensive description of the geological structure below a site.

  20. Precursory changes in seismic velocity for the spectrum of earthquake failure modes

    Science.gov (United States)

    Scuderi, M.M.; Marone, C.; Tinti, E.; Di Stefano, G.; Collettini, C.

    2016-01-01

    Temporal changes in seismic velocity during the earthquake cycle have the potential to illuminate physical processes associated with fault weakening and connections between the range of fault slip behaviors including slow earthquakes, tremor and low frequency earthquakes1. Laboratory and theoretical studies predict changes in seismic velocity prior to earthquake failure2, however tectonic faults fail in a spectrum of modes and little is known about precursors for those modes3. Here we show that precursory changes of wave speed occur in laboratory faults for the complete spectrum of failure modes observed for tectonic faults. We systematically altered the stiffness of the loading system to reproduce the transition from slow to fast stick-slip and monitored ultrasonic wave speed during frictional sliding. We find systematic variations of elastic properties during the seismic cycle for both slow and fast earthquakes indicating similar physical mechanisms during rupture nucleation. Our data show that accelerated fault creep causes reduction of seismic velocity and elastic moduli during the preparatory phase preceding failure, which suggests that real time monitoring of active faults may be a means to detect earthquake precursors. PMID:27597879

  1. Inter-laboratory agreement on embryo classification and clinical decision: Conventional morphological assessment vs. time lapse.

    Science.gov (United States)

    Martínez-Granados, Luis; Serrano, María; González-Utor, Antonio; Ortíz, Nereyda; Badajoz, Vicente; Olaya, Enrique; Prados, Nicolás; Boada, Montse; Castilla, Jose A

    2017-01-01

    The aim of this study is to determine inter-laboratory variability on embryo assessment using time-lapse platform and conventional morphological assessment. This study compares the data obtained from a pilot study of external quality control (EQC) of time lapse, performed in 2014, with the classical EQC of the Spanish Society for the Study of Reproductive Biology (ASEBIR) performed in 2013 and 2014. In total, 24 laboratories (8 using EmbryoScope™, 15 using Primo Vision™ and one with both platforms) took part in the pilot study. The clinics that used EmbryoScope™ analysed 31 embryos and those using Primo Vision™ analysed 35. The classical EQC was implemented by 39 clinics, based on an analysis of 25 embryos per year. Both groups were required to evaluate various qualitative morphological variables (cell fragmentation, the presence of vacuoles, blastomere asymmetry and multinucleation), to classify the embryos in accordance with ASEBIR criteria and to stipulate the clinical decision taken. In the EQC time-lapse pilot study, the groups were asked to determine, as well as the above characteristics, the embryo development times, the number, opposition and size of pronuclei, the direct division of 1 into 3 cells and/or of 3 into 5 cells and false divisions. The degree of agreement was determined by calculating the intra-class correlation coefficients and the coefficient of variation for the quantitative variables and the Gwet index for the qualitative variables. For both EmbryoScope™ and Primo Vision™, two periods of greater inter-laboratory variability were observed in the times of embryo development events. One peak of variability was recorded among the laboratories addressing the first embryo events (extrusion of the second polar body and the appearance of pronuclei); the second peak took place between the times corresponding to the 8-cell and morula stages. In most of the qualitative variables analysed regarding embryo development, there was almost

  2. Seismic wave velocity of rocks in the Oman ophiolite: constraints for petrological structure of oceanic crust

    Science.gov (United States)

    Saito, S.; Ishikawa, M.; Shibata, S.; Akizuki, R.; Arima, M.; Tatsumi, Y.; Arai, S.

    2010-12-01

    Evaluation of rock velocities and comparison with velocity profiles defined by seismic refraction experiments are a crucial approach for understanding the petrological structure of the crust. In this study, we calculated the seismic wave velocities of various types of rocks from the Oman ophiolite in order to constrain a petrological structure of the oceanic crust. Christensen & Smewing (1981, JGR) have reported experimental elastic velocities of rocks from the Oman ophiolite under oceanic crust-mantle conditions (6-430 MPa). However, in their relatively low-pressure experiments, internal pore-spaces might affect the velocity and resulted in lower values than the intrinsic velocity of sample. In this study we calculated the velocities of samples based on their modal proportions and chemical compositions of mineral constituents. Our calculated velocities represent the ‘pore-space-free’ intrinsic velocities of the sample. We calculated seismic velocities of rocks from the Oman ophiolite including pillow lavas, dolerites, plagiogranites, gabbros and peridotites at high-pressure-temperature conditions with an Excel macro (Hacker & Avers 2004, G-cubed). The minerals used for calculations for pillow lavas, dolerites and plagiogranites were Qtz, Pl, Prh, Pmp, Chl, Ep, Act, Hbl, Cpx and Mag. Pl, Hbl, Cpx, Opx and Ol were used for the calculations for gabbros and peridotites. Assuming thermal gradient of 20° C/km and pressure gradient of 25 MPa/km, the velocities were calculated in the ranges from the atmospheric pressure (0° C) to 200 MPa (160° C). The calculation yielded P-wave velocities (Vp) of 6.5-6.7 km/s for the pillow lavas, 6.6-6.8 km/s for the dolerites, 6.1-6.3 km/s for the plagiogranites, 6.9-7.5 km/s for the gabbros and 8.1-8.2 km/s for the peridotites. On the other hand, experimental results reported by Christensen & Smewing (1981, JGR) were 4.5-5.9 km/s for the pillow lavas, 5.5-6.3 km/s for the dolerites, 6.1-6.3 km/s for the plagiogranites, 6

  3. Estimation of strain sensitivity of seismic velocity changes using the Earth tide: Analyses of seismic small array data at Izu-Oshima volcano, Japan

    Science.gov (United States)

    Takano, T.; Nishimura, T.; Nakahara, H.; Ueda, H.; Fujita, E.

    2017-12-01

    Seismic velocity changes in the crust and/or subsurface have been often observed in association with the occurrences of earthquakes or volcanic activities. Mechanisms of the velocity changes are, for example, non-linear behavior of subsurface, strain changes, ground water level changes etc. To examine the effects of strain changes, the solid earth tide is a good input signal because the strain sensitivity of velocity changes can be measured at many places by using seismic interferometry [Takano et al., 2014; Hillers et al., 2015]. However, there are few reports which detect the velocity changes due to the Earth tide by seismic interferometry. The aim of this study is to estimate the strain sensitivity of velocity changes using the Earth tide at Izu-Oshima volcano, where the small seismic array and seismic network are deployed. We analyze the ambient noises recorded at the seismic array operated by NIED. The array consists of 7 short-period sensors with a diameter of 100 m. The continuous data from 1 Apr. 2014 to 1 Apr. 2015 is analyzed. The tidal strain is extracted from the raw data of the strain-meter deployed by JMA using Baytap-08 [Tamura et al., 1991]. We estimate the velocity changes due to the Earth tide as follows. First, we divide the observation period into five episodes: dilatational and contractional, according to volumetric strain values. CCFs of ambient noise at 2 - 4 Hz are separately stacked for each divided episode. Subsequently, we measure the velocity changes by calculating the phase delay between stacked CCFs at lapse time of less than 6 s. It is recognized that seismic velocity decreases during the dilatational episode with respect to the contractional episode. Strain sensitivity of seismic velocity changes, which is obtained by averaging for six station pairs, is estimated to be (-1.6±0.5)×104 strain-1. The strain sensitivity of the seismic velocity changes is consistent with that at the foot of Mt. Iwate [Takano et al., 2014]. We also

  4. Comparison of field and laboratory seismic velocity anisotropy measurement (scaling factor)

    Czech Academy of Sciences Publication Activity Database

    Vilhelm, J.; Rudajev, Vladimír; Živor, Roman; Lokajíček, Tomáš; Pros, Zdeněk

    2008-01-01

    Roč. 5, č. 2 (2008), s. 161-169 ISSN 1214-9705. [Czech-Polish-Slovak Symposium on Mining and Environmental Geophysics. Janov nad Nisou, 24.09.2007-27.09.2007] R&D Projects: GA ČR GA205/06/0906 Institutional research plan: CEZ:AV0Z30130516 Keywords : ultrasound sounding * seismic velocity * anisotropy * shallow seismic refraction Subject RIV: DC - Siesmology, Volcanology, Earth Structure http://www.irsm.cas.cz/?Lang=ENG&Menu=25,29,0,0;&File=Obsah/AGG/Contents/AGGC5_2(150)08.htm

  5. Seismic velocity uncertainties and their effect on geothermal predictions: A case study

    Science.gov (United States)

    Rabbel, Wolfgang; Köhn, Daniel; Bahadur Motra, Hem; Niederau, Jan; Thorwart, Martin; Wuttke, Frank; Descramble Working Group

    2017-04-01

    Geothermal exploration relies in large parts on geophysical subsurface models derived from seismic reflection profiling. These models are the framework of hydro-geothermal modeling, which further requires estimating thermal and hydraulic parameters to be attributed to the seismic strata. All petrophysical and structural properties involved in this process can be determined only with limited accuracy and thus impose uncertainties onto the resulting model predictions of temperature-depth profiles and hydraulic flow, too. In the present study we analyze sources and effects of uncertainties of the seismic velocity field, which translate directly into depth uncertainties of the hydraulically and thermally relevant horizons. Geological sources of these uncertainties are subsurface heterogeneity and seismic anisotropy, methodical sources are limitations in spread length and physical resolution. We demonstrate these effects using data of the EU-Horizon 2020 project DESCRAMBLE investigating a shallow super-critical geothermal reservoir in the Larderello area. The study is based on 2D- and 3D seismic reflection data and laboratory measurements on representative rock samples under simulated in-situ conditions. The rock samples consistently show P-wave anisotropy values of 10-20% order of magnitude. However, the uncertainty of layer depths induced by anisotropy is likely to be lower depending on the accuracy, with which the spatial orientation of bedding planes can be determined from the seismic reflection images.

  6. Seismological implications of a lithospheric low seismic velocity zone in Mars

    Science.gov (United States)

    Zheng, Yingcai; Nimmo, Francis; Lay, Thorne

    2015-03-01

    Most seismological models for the interior of Mars lack an upper mantle low velocity zone. However, there is expected to be a large thermal gradient across the stagnant conductive lid (lithosphere) of Mars. This gradient should tend to decrease elastic wave velocities with increasing depth, with this effect dominating the opposing tendency caused by increasing pressure with depth because Mars has low gravity. An upper mantle lithosphere with a low velocity zone (LVZ) beneath a thin high velocity "seismic lid" is thus predicted. The upcoming NASA InSight mission includes a three-component seismometer, which should provide the first opportunity to directly detect any lithospheric LVZ in Mars. Seismic wavefields expected for Mars mantle velocity structures with or without a strong LVZ are very distinct. The LVZ models predict shadow zones for high-frequency seismic body wave phases such as P, S, PP and SS, etc. The most diagnostic waves that can be used to evaluate presence of a lithospheric LVZ given a single seismometer are intermediate-period global surface waves, which travel along the great circle from a seismic source to the seismometer. An LVZ produces distinctive dispersion, with a Rayleigh wave Airy phase around 100 s period and very different surface wave seismograms compared to a model with no LVZ. Even a single observation of long-period surface waves from a known range can be diagnostic of the lithospheric structure. Establishing the existence of an LVZ has major implications for thermal evolution, volatile content and internal dynamics of the planet.

  7. Distributed Acoustic Sensing for Seismic Monitoring of The Near Surface: A Traffic-Noise Interferometry Case Study.

    Science.gov (United States)

    Dou, Shan; Lindsey, Nate; Wagner, Anna M; Daley, Thomas M; Freifeld, Barry; Robertson, Michelle; Peterson, John; Ulrich, Craig; Martin, Eileen R; Ajo-Franklin, Jonathan B

    2017-09-14

    Ambient-noise-based seismic monitoring of the near surface often has limited spatiotemporal resolutions because dense seismic arrays are rarely sufficiently affordable for such applications. In recent years, however, distributed acoustic sensing (DAS) techniques have emerged to transform telecommunication fiber-optic cables into dense seismic arrays that are cost effective. With DAS enabling both high sensor counts ("large N") and long-term operations ("large T"), time-lapse imaging of shear-wave velocity (V S ) structures is now possible by combining ambient noise interferometry and multichannel analysis of surface waves (MASW). Here we report the first end-to-end study of time-lapse V S imaging that uses traffic noise continuously recorded on linear DAS arrays over a three-week period. Our results illustrate that for the top 20 meters the V S models that is well constrained by the data, we obtain time-lapse repeatability of about 2% in the model domain-a threshold that is low enough for observing subtle near-surface changes such as water content variations and permafrost alteration. This study demonstrates the efficacy of near-surface seismic monitoring using DAS-recorded ambient noise.

  8. History Matching of 4D Seismic Data Attributes using the Ensemble Kalman Filter

    KAUST Repository

    Ravanelli, Fabio M.

    2013-05-01

    One of the most challenging tasks in the oil industry is the production of reliable reservoir forecast models. Because of different sources of uncertainties the numerical models employed are often only crude approximations of the reality. This problem is tackled by the conditioning of the model with production data through data assimilation. This process is known in the oil industry as history matching. Several recent advances are being used to improve history matching reliability, notably the use of time-lapse seismic data and automated history matching software tools. One of the most promising data assimilation techniques employed in the oil industry is the ensemble Kalman filter (EnKF) because its ability to deal with highly non-linear models, low computational cost and easy computational implementation when compared with other methods. A synthetic reservoir model was used in a history matching study designed to predict the peak production allowing decision makers to properly plan field development actions. If only production data is assimilated, a total of 12 years of historical data is required to properly characterize the production uncertainty and consequently the correct moment to take actions and decommission the field. However if time-lapse seismic data is available this conclusion can be reached 4 years in advance due to the additional fluid displacement information obtained with the seismic data. Production data provides geographically sparse data in contrast with seismic data which are sparse in time. Several types of seismic attributes were tested in this study. Poisson’s ratio proved to be the most sensitive attribute to fluid displacement. In practical applications, however the use of this attribute is usually avoided due to poor quality of the data. Seismic impedance tends to be more reliable. Finally, a new conceptual idea was proposed to obtain time-lapse information for a history matching study. The use of crosswell time-lapse seismic

  9. MEASUREMENT OF COMPRESSIONAL-WAVE SEISMIC VELOCITIES IN 29 WELLS AT THE HANFORD SITE

    Energy Technology Data Exchange (ETDEWEB)

    PETERSON SW

    2010-10-08

    Check shot seismic velocity surveys were collected in 100 B/C, 200 East, 200-PO-1 Operational Unit (OU), and the Gable Gap areas in order to provide time-depth correlation information to aid the interpretation of existing seismic reflection data acquired at the Hanford Site (Figure 1). This report details results from 5 wells surveyed in fiscal year (FY) 2008, 7 wells in FY 2009, and 17 wells in FY 2010 and provides summary compressional-wave seismic velocity information to help guide future seismic survey design as well as improve current interpretations of the seismic data (SSC 1979/1980; SGW-39675; SGW-43746). Augmenting the check shot database are four surveys acquired in 2007 in support of the Bechtel National, Inc. Waste Treatment Plant construction design (PNNL-16559, PNNL-16652), and check shot surveys in three wells to support seismic testing in the 200 West Area (Waddell et al., 1999). Additional sonic logging was conducted during the late 1970s and early 1980s as part of the Basalt Waste Isolation Program (BWIP) (SSC 1979/1980) and check shot/sonic surveys as part of the safety report for the Skagit/Hanford Nuclear project (RDH/10-AMCP-0164). Check shot surveys are used to obtain an in situ measure of compressional-wave seismic velocity for sediment and rock in the vicinity of the well point, and provide the seismic-wave travel time to geologic horizons of interest. The check shot method deploys a downhole seismic receiver (geophone) to record the arrival of seismic waves generated by a source at the ground surface. The travel time of the first arriving seismic-wave is determined and used to create a time-depth function to correlate encountered geologic intervals with the seismic data. This critical tie with the underlying geology improves the interpretation of seismic reflection profile information. Fieldwork for this investigation was conducted by in house staff during the weeks of September 22, 2008 for 5 wells in the 200 East Area (Figure 2); June 1

  10. A state-space Bayesian framework for estimating biogeochemical transformations using time-lapse geophysical data

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.; Hubbard, S.; Williams, K.; Pride, S.; Li, L.; Steefel, C.; Slater, L.

    2009-04-15

    We develop a state-space Bayesian framework to combine time-lapse geophysical data with other types of information for quantitative estimation of biogeochemical parameters during bioremediation. We consider characteristics of end-products of biogeochemical transformations as state vectors, which evolve under constraints of local environments through evolution equations, and consider time-lapse geophysical data as available observations, which could be linked to the state vectors through petrophysical models. We estimate the state vectors and their associated unknown parameters over time using Markov chain Monte Carlo sampling methods. To demonstrate the use of the state-space approach, we apply it to complex resistivity data collected during laboratory column biostimulation experiments that were poised to precipitate iron and zinc sulfides during sulfate reduction. We develop a petrophysical model based on sphere-shaped cells to link the sulfide precipitate properties to the time-lapse geophysical attributes and estimate volume fraction of the sulfide precipitates, fraction of the dispersed, sulfide-encrusted cells, mean radius of the aggregated clusters, and permeability over the course of the experiments. Results of the case study suggest that the developed state-space approach permits the use of geophysical datasets for providing quantitative estimates of end-product characteristics and hydrological feedbacks associated with biogeochemical transformations. Although tested here on laboratory column experiment datasets, the developed framework provides the foundation needed for quantitative field-scale estimation of biogeochemical parameters over space and time using direct, but often sparse wellbore data with indirect, but more spatially extensive geophysical datasets.

  11. Feeling the Heat: Supraglacial Lake Changes as Observed via Time-Lapse Photography, Ngozumpa Glacier, Nepal

    Science.gov (United States)

    Horodyskyj, U. N.; Breashears, D.; Bilham, R. G.

    2011-12-01

    Supraglacial lakes are suspected of playing a catalytic role in the current rapid melting rate of temperate glaciers. Our field work on the Ngozumpa glacier, in the Nepalese Himalaya, was targeted to quantify the physics of this process. A field season was conducted in June 2011 to investigate the formation and evolution of these lakes via time-lapse photography. One supraglacial lake in particular was chosen for more intensive study. A pressure transducer recorded lake level changes throughout the field season; probes measured surface water temperature, water temperature at depth, and air temperature; and solar irradiation (incoming and outgoing) was measured with a pair of silicon pyranometers. Depth surveys were conducted, water samples were collected, and melt rates on north and south facing ice walls also were measured with a laser rangefinder during hours of peak insolation. During the course of the field season, 28 cm of overall water rise was measured in the lake. Two major icefall events a week apart contributed to 8 and 6 cm, respectively, rise alone. Surface water and air temperatures increased during this time, along with the amount of solar irradiation reaching the surface of the lake. South-facing ice walls were found to melt faster, but no walls were found to be immune to melt and collapse. Hourly time-lapse photography captured a major icefall in this lake, while another camera captured a larger lake farther upglacier draining more than 3 meters overnight. A third camera, aimed near the terminus, captured a lake changing in color (from milky blue to brown) and doubling in size during the field season. These initial results show substantial change in a short amount of time. Continued time-lapse photography should provide us with an even better record of surface evolution on this climatically sensitive glacier in the Himalaya.

  12. Time-lapse electrical geophysical monitoring of amendment-based biostimulation

    Science.gov (United States)

    Johnson, Timothy C.; Versteeg, Roelof J.; Day-Lewis, Frederick D.; Major, William; Lane, John W.

    2015-01-01

    Biostimulation is increasingly used to accelerate microbial remediation of recalcitrant groundwater contaminants. Effective application of biostimulation requires successful emplacement of amendment in the contaminant target zone. Verification of remediation performance requires postemplacement assessment and contaminant monitoring. Sampling-based approaches are expensive and provide low-density spatial and temporal information. Time-lapse electrical resistivity tomography (ERT) is an effective geophysical method for determining temporal changes in subsurface electrical conductivity. Because remedial amendments and biostimulation-related biogeochemical processes often change subsurface electrical conductivity, ERT can complement and enhance sampling-based approaches for assessing emplacement and monitoring biostimulation-based remediation.Field studies demonstrating the ability of time-lapse ERT to monitor amendment emplacement and behavior were performed during a biostimulation remediation effort conducted at the Department of Defense Reutilization and Marketing Office (DRMO) Yard, in Brandywine, Maryland, United States. Geochemical fluid sampling was used to calibrate a petrophysical relation in order to predict groundwater indicators of amendment distribution. The petrophysical relations were field validated by comparing predictions to sequestered fluid sample results, thus demonstrating the potential of electrical geophysics for quantitative assessment of amendment-related geochemical properties. Crosshole radar zero-offset profile and borehole geophysical logging were also performed to augment the data set and validate interpretation.In addition to delineating amendment transport in the first 10 months after emplacement, the time-lapse ERT results show later changes in bulk electrical properties interpreted as mineral precipitation. Results support the use of more cost-effective surface-based ERT in conjunction with limited field sampling to improve spatial

  13. Time-Lapse Electrical Geophysical Monitoring of Amendment-Based Biostimulation

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Timothy C.; Versteeg, Roelof; Day-Lewis, Frederick D.; Major, William; Lane, John W.

    2015-12-02

    Biostimulation is increasingly used to accelerate microbial remediation of recalcitrant groundwater contaminants. Effective application of biostimulation requires successful emplacement of amendment in the contaminant target zone. Verification of remediation performance requires postemplacement assessment and contaminant monitoring. Sampling based approaches are expensive and provide low-density spatial and temporal information. Time-lapse electrical resistivity tomography (ERT) is an effective geophysical method for determining temporal changes in subsurface electrical conductivity. Because remedial amendments and biostimulation-related biogeochemical processes often change subsurface electrical conductivity, ERT can complement and enhance sampling-based approaches for assessing emplacement and monitoring biostimulation-based remediation. Field studies demonstrating the ability of time-lapse ERT to monitor amendment emplacement and behavior were performed during a biostimulation remediation effort conducted at the Department of Defense Reutilization and Marketing Office (DRMO) Yard, in Brandywine, Maryland, United States. Geochemical fluid sampling was used to calibrate a petrophysical relation in order to predict groundwater indicators of amendment distribution. The petrophysical relations were field validated by comparing predictions to sequestered fluid sample results, thus demonstrating the potential of electrical geophysics for quantitative assessment of amendment-related geochemical properties. Crosshole radar zero-offset profile and borehole geophysical logging were also performed to augment the data set and validate interpretation. In addition to delineating amendment transport in the first 10 months after emplacement, the time-lapse ERT results show later changes in bulk electrical properties interpreted as mineral precipitation. Results support the use of more cost-effective surfacebased ERT in conjunction with limited field sampling to improve spatial

  14. Time-lapse 3D imaging of calcite precipitation in a microporous column

    Science.gov (United States)

    Godinho, Jose R. A.; Withers, Philip J.

    2018-02-01

    Time-lapse X-ray computed tomography is used to image the evolution of calcite precipitation during flow through microporous quartz over the course of 400 h. The growth rate decreases by more than seven times, which is linked to the clogging of flow paths that restricts flow to some regions of the column. Fewer precipitates are observed as a function of column depth, which is found to be related to a differential nucleation density along the sample. A higher nucleation density closer to the inlet implies more crystal volume increase per unit of time without affecting the rate if normalized to the surface area of crystals. Our overall growth rates measured in porous media are orders of magnitude slower than growth rates derived from traditional precipitation experiments on free surfaces. Based on our time-lapse results we hypothesize a scenario where the evolving distribution of precipitates within a pore structure during precipitation progressively modifies the local transport through the pores. Within less permeable regions the saturation index may be lower than along the main flow paths. Therefore, the reactive crystal surfaces within those regions grow at a slower rate than that expected from the bulk fluid composition. Since the amount of reactive surface area within these less permeable regions increases over time, the overall growth rate decreases without a necessary significant change of the bulk fluid composition along more permeable flow paths. In conclusion, the overall growth rates in an evolving porous media expected from bulk fluid compositions alone can be overestimated due to the development of stagnant sub-regions where the reactive surface area is bath by a solution with lower saturation index. In this context we highlight the value of time-lapse 3D studies for understanding the dynamics of mineral precipitation in porous media.

  15. Influence of apparent wave velocity on seismic performance of a super-long-span triple-tower suspension bridge

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2015-06-01

    Full Text Available As one of the main characteristics of seismic waves, apparent wave velocity has great influence on seismic responses of long-span suspension bridges. Understanding these influences is important for seismic design. In this article, the critical issues concerning the traveling wave effect analysis are first reviewed. Taizhou Bridge, the longest triple-tower suspension bridge in the world, is then taken as an example for this investigation. A three-dimensional finite element model of the bridge is established in ABAQUS, and the LANCZOS eigenvalue solver is employed to calculate the structural dynamic characteristics. Traveling wave effect on seismic responses of these long-span triple-tower suspension bridges is investigated. Envelopes of seismic shear force and moment in the longitudinal direction along the three towers, relative displacements between the towers and the girder, and reaction forces at the bottoms of the three towers under different apparent wave velocities are calculated and presented in detail. The results show that the effect of apparent wave velocity on the seismic responses of triple-tower suspension bridge fluctuates when the velocity is lower than 2000 m/s, and the effects turn stable when the velocity becomes larger. In addition, the effects of traveling wave are closely related to spectral characteristics and propagation direction of the seismic wave, and seismic responses of components closer to the source are relatively larger. Therefore, reliable estimation of the seismic input and apparent wave velocity according to the characteristics of the bridge site are significant for accurate prediction of seismic responses. This study provides critical reference for seismic analysis and design of long-span triple-tower suspension bridges.

  16. Investigation of temporal and lateral variations of seismic velocities in south Iceland using ray tracing.

    Science.gov (United States)

    Kjartansson, Einar; Bjarnason, Ingi Th.

    2017-04-01

    Tools for ray-tracing through one dimensional earth models consisting of layers of constant velocity gradients, and continuous values across layers, have been developed. They are used to investigate stability and robustness of earthquake locations and velocity determinations in the South Iceland Lowlands (SIL) a transform seismic zone. These tools will also be used to invert for velocity functions for different regions and time periods, by inverting simultaneously for micro-earthquake source parameters and P and S velocities. Increase of velocity gradient with depth will cause rays with different take-off angles to cross, which can result in focusing and triplication when velocity is plotted versus time. It is therefore important to constrain the velocity solutions to avoid this. Large changes in gradient between adjacent layers causes variability of ray density and geometrical spreading, particularly for rays that turn just below the boundaries. This may create artificial clustering in the depth distribution of micro-earthquake source solutions. Resampling of the velocity functions using cubic spline interpolation can be used to reduce these effects. The software is open source and can be accessed at https://github.com/4dseismic

  17. Segmentation Method of Time-Lapse Microscopy Images with the Focus on Biocompatibility Assessment

    Czech Academy of Sciences Publication Activity Database

    Soukup, Jindřich; Císař, P.; Šroubek, Filip

    2016-01-01

    Roč. 22, č. 3 (2016), s. 497-506 ISSN 1431-9276 R&D Projects: GA ČR GA13-29225S Grant - others:GA MŠk(CZ) LO1205; GA UK(CZ) 914813/2013; GA UK(CZ) SVV-2016-260332; CENAKVA(CZ) CZ.1.05/2.1.00/01.0024 Institutional support: RVO:67985556 Keywords : phase contrast microscopy * segmentation * biocompatibility assessment * time-lapse * cytotoxicity testing Subject RIV: JD - Computer Applications, Robotics Impact factor: 1.891, year: 2016 http://library.utia.cas.cz/separaty/2016/ZOI/soukupj-0460642.pdf

  18. 4D seismic reservoir characterization, integrated with geo-mechanical modelling

    NARCIS (Netherlands)

    Angelov, P.V.

    2009-01-01

    Hydrocarbon production induces time-lapse changes in the seismic attributes (travel time and amplitude) both at the level of the producing reservoir and in the surrounding rock. The detected time-lapse changes in the seismic are induced from the changes in the petrophysical properties of the rock,

  19. 4-D seismic in a complex fluvial reservoir: the Snorre feasibility study

    NARCIS (Netherlands)

    Smith, P.; Berg, J.I.; Eidsvig, S.; Magnus, I.; Verhelst, F.J.P.C.M.G.; Helgesen, J.

    2001-01-01

    The saga petroleum, discoverer of Snorre Field, describe's how 3-D seismic surveys are used to determine the value of time-lapse seismic data for field management. Careful examination of the repeatability of the time-lapse data sets, before interpretation stark, establishes a framework defining the

  20. Shear-wave velocity of marine sediments offshore Taiwan using ambient seismic noise

    Science.gov (United States)

    Lin, Yu-Tse; Lin, Jing-Yi; Kuo-Chen, Hao; Yeh, Yi-Chin; Cheng, Win-Bin

    2017-04-01

    Seismic ambient noise technology has many advantages over the traditional two-station method. The most important one is that noise is happening all the time and it can be widely and evenly distributed. Thus, the Green's Function of any station pair can be obtained through the data cross-correlation process. Many related studies have been performed to estimate the velocity structures based on the inland area. Only a few studies were reported for the marine area due to the relatively shorter recording time of ocean bottom seismometers (OBS) deployment and the high cost of the marine experiment. However, the understanding about the shear-wave velocity (Vs) of the marine sediments is very crucial for the hazard assessment related to submarine landslides, particularly with the growing of submarine resources exploration. In this study, we applied the ambient noise technique to four OBS seismic networks located offshore Taiwan in the aim of getting more information about the noise sources and having the preliminary estimation for the Vs of the marine sediments. Two of the seismic networks were deployed in the NE part of Taiwan, near the Ryukyu subduction system, whereas the others were in the SW area, on the continental margin rich in gas hydrate. Generally, ambient seismic noise could be associated with wind, ocean waves, rock fracturing and anthropogenic activity. In the southwestern Taiwan, the cross-correlation function obtained from two seismic networks indicate similar direction, suggestion that the source from the south part of the network could be the origin of the noise. However, the two networks in the northeastern Taiwan show various source direction, which could be caused by the abrupt change of bathymetry or the volcanic degassing effect frequently observed by the marine geophysical method in the area. The Vs determined from the dispersion curve shows a relatively higher value for the networks in the Okinawa Trough (OT) off NE Taiwan than that in the

  1. A seismic waves velocity model for Gran Canaria Island from ambient noise correlations

    Science.gov (United States)

    García-Jerez, Antonio; Almendros, Javier; Martínez-Arévalo, Carmen; de Lis Mancilla, Flor; Luzón, Francisco; Carmona, Enrique; Martín, Rosa; Sánchez, Nieves

    2014-05-01

    We have analysed continuous ambient seismic noise recorded by a temporary array in Gran Canaria (Canary Islands, Spain) in order to find a velocity model for the top few kilometers. The SISTEVOTENCAN-IGN seismic array consisted of five broadband stations surrounding a sixth central one placed close to Pico de las Nieves, at the center of the island. The array had a radius of 12-14 km, with interstation distances ranging from 10 to 27 km. This network was operative from December 2009 to November 2011. The Green's functions between the 15 pairs of stations have been estimated in the time domain by stacking cross-correlations of 60-s time windows for the whole recording period (~2 years). The effects of several processing adjustments such as 1-bit normalization and spectral whitening are discussed. We observe significant differences (mainly in amplitude) between causal and acausal parts of the estimated Green's functions, which can be associated to an uneven distribution of the seismic noise sources. The application of a phase-matched filter based on an average dispersion curve allowed the effective reduction of some spurious early arrivals and the selection of fundamental-mode Rayleigh wave pulses, making possible an automatic extraction of their group velocities. Then, Rayleigh-wave dispersion curves were retrieved for the set of paths by using frequency-time analysis (FTAN) as well as by following the procedure described by Herrin and Goforth (1977, BSSA) based on the iterative fitting of a phase-matched filter which optimally undisperses the signal. Reliable curves were obtained from 1 s to 6-7 s with group velocities ranging between 1.5 and 2.2 km/s. Some lateral variations in velocity have been detected in spite of the limited spatial coverage and path density, which substantially restricted the resolution. A mean S-wave velocity model has been inverted for this area down to ~3 km.

  2. Possible mechanism of polyspermy block in human oocytes observed by time-lapse cinematography.

    Science.gov (United States)

    Mio, Yasuyuki; Iwata, Kyoko; Yumoto, Keitaro; Kai, Yoshiteru; Sargant, Haruka C; Mizoguchi, Chizuru; Ueda, Minako; Tsuchie, Yuka; Imajo, Akifumi; Iba, Yumiko; Nishikori, Kyoko

    2012-09-01

    To analyze the fertilization process related to polyspermy block in human oocytes using an in vitro culturing system for time-lapse cinematography. We had 122 oocytes donated for this study from couples that provided informed consent. We recorded human oocytes at 2,000 to 2,800 frames every 10 s during the fertilization process and thereafter every 2 min using a new in vitro culture system originally developed by the authors for time-lapse cinematography. We displayed 30 frames per second for analysis of the polyspermy block during fertilization. Three oocytes showed the leading and following sperm within the zona pellucida in the same microscopic field. The dynamic images obtained during the fertilization process using this new system revealed that once a leading sperm penetrated the zona pellucida and attached to the oocyte membrane, a following sperm was arrested from further penetration into the zona pellucida within 10 s. The present results strongly suggest the existence of a novel mechanism of polyspermy block that takes place at the zona pellucida immediately after fertilization. These findings are clearly different from previous mechanisms describing polyspermy block as the oocyte membrane block to sperm penetration and the zona reaction. The finding presented herein thus represents a novel discovery about the highly complicated polyspermy block mechanism occurring in human oocytes.

  3. Analysis of compaction initiation in human embryos by using time-lapse cinematography.

    Science.gov (United States)

    Iwata, Kyoko; Yumoto, Keitaro; Sugishima, Minako; Mizoguchi, Chizuru; Kai, Yoshiteru; Iba, Yumiko; Mio, Yasuyuki

    2014-04-01

    To analyze the initiation of compaction in human embryos in vitro by using time-lapse cinematography (TLC), with the goal of determining the precise timing of compaction and clarifying the morphological changes underlying the compaction process. One hundred and fifteen embryos donated by couples with no further need for embryo-transfer were used in this study. Donated embryos were thawed and processed, and then their morphological behavior during the initiation of compaction was dynamically observed via time-lapse cinematography (TLC) for 5 days. Although the initiation of compaction occurred throughout the period from the 4-cell to 16-cell stage, 99 (86.1 %) embryos initiated compaction at the 8-cell stage or later, with initiation at the 8-cell stage being most frequent (22.6 %). Of these 99 embryos, 49.5 % developed into good-quality blastocysts. In contrast, of the 16 (13.9 %) embryos that initiated compaction prior to the 8-cell stage, only 18.8 % developed into good-quality blastocysts. Embryos that initiated compaction before the 8-cell stage showed significantly higher numbers of multinucleated blastomeres, due to asynchronism in nuclear division at the third mitotic division resulting from cytokinetic failure. The initiation of compaction primarily occurs at the third mitotic division or later in human embryos. Embryos that initiate compaction before the 8-cell stage are usually associated with aberrant embryonic development (i.e., cytokinetic failure accompanied by karyokinesis).

  4. The Extreme Ice Survey: Capturing and Conveying Glacial Processes Through Time-Lapse Imagery and Narration

    Science.gov (United States)

    Balog, J. D.; Box, J. E.; Pfeffer, W. T.; Hood, E. W.; Fagre, D. B.; Anker, C.; O'Neel, S.

    2010-12-01

    The Extreme Ice Survey (EIS) uses time-lapse photography, conventional photography, and video to document rapid change in the Earth's glacial ice. The EIS team currently has 38 time-lapse cameras at sites in Greenland, Iceland, Alaska, the Rocky Mountains and Nepal. EIS supplements this ongoing record with annual repeat photography in British Columbia, Iceland, the Alps, and Bolivia. EIS imagery supplies basic knowledge in glacier dynamics to the science community, as well as compelling, engaging narratives to the general public about the immediacy of the Anthropocene and climate change. Visual materials from EIS have impacted more than 150 million people, ranging from White House staff, the U. S. Congress and government agency officials to globally influential corporate officers and all age strata of the general public. Media products include a National Geographic/NOVA special, two National Geographic magazine articles, a feature in Parade magazine (circulation 71 million), and numerous presentations on CNN, NBC, BBC and National Public Radio. Columbia Glacier, Alaska, June 2006, May 2007, June 2008 terminus indicated.

  5. Time-lapse crystallography snapshots of a double-strand break repair polymerase in action.

    Science.gov (United States)

    Jamsen, Joonas A; Beard, William A; Pedersen, Lars C; Shock, David D; Moon, Andrea F; Krahn, Juno M; Bebenek, Katarzyna; Kunkel, Thomas A; Wilson, Samuel H

    2017-08-15

    DNA polymerase (pol) μ is a DNA-dependent polymerase that incorporates nucleotides during gap-filling synthesis in the non-homologous end-joining pathway of double-strand break repair. Here we report time-lapse X-ray crystallography snapshots of catalytic events during gap-filling DNA synthesis by pol μ. Unique catalytic intermediates and active site conformational changes that underlie catalysis are uncovered, and a transient third (product) metal ion is observed in the product state. The product manganese coordinates phosphate oxygens of the inserted nucleotide and PP i . The product metal is not observed during DNA synthesis in the presence of magnesium. Kinetic analyses indicate that manganese increases the rate constant for deoxynucleoside 5'-triphosphate insertion compared to magnesium. The likely product stabilization role of the manganese product metal in pol μ is discussed. These observations provide insight on structural attributes of this X-family double-strand break repair polymerase that impact its biological function in genome maintenance.DNA polymerase (pol) μ functions in DNA double-strand break repair. Here the authors use time-lapse X-ray crystallography to capture the states of pol µ during the conversion from pre-catalytic to product complex and observe a third transiently bound metal ion in the product state.

  6. Time-Lapse Electrical Resistivity Investigations for Imaging the Grouting Injection in Shallow Subsurface Cavities

    Directory of Open Access Journals (Sweden)

    Muhammad Farooq

    2014-01-01

    Full Text Available The highway of Yongweol-ri, Muan-gun, south-western part of the South Korean Peninsula, is underlain by the abandoned of subsurface cavities, which were discovered in 2005. These cavities lie at shallow depths with the range of 5∼15 meters below the ground surface. Numerous subsidence events have repeatedly occurred in the past few years, damaging infrastructure and highway. As a result of continuing subsidence issues, the Korean Institute of Geosciences and Mineral Resources (KIGAM was requested by local administration to resolve the issue. The KIGAM used geophysical methods to delineate subsurface cavities and improve more refined understanding of the cavities network in the study area. Cement based grouting has been widely employed in the construction industry to reinforce subsurface ground. In this research work, time-lapse electrical resistivity surveys were accomplished to monitor the grouting injection in the subsurface cavities beneath the highway, which have provided a quasi-real-time monitoring for modifying the subsurface cavities related to ground reinforcement, which would be difficult with direct methods. The results obtained from time-lapse electrical resistivity technique have satisfactory imaged the grouting injection experiment in the subsurface cavities beneath the highway. Furthermore, the borehole camera confirmed the presence of grouting material in the subsurface cavities, and hence this procedure increases the mechanical resistance of subsurface cavities below the highway.

  7. A study on quality-adjusted impact of time lapse on iris recognition

    Science.gov (United States)

    Sazonova, Nadezhda; Hua, Fang; Liu, Xuan; Remus, Jeremiah; Ross, Arun; Hornak, Lawrence; Schuckers, Stephanie

    2012-06-01

    Although human iris pattern is widely accepted as a stable biometric feature, recent research has found some evidences on the aging effect of iris system. In order to investigate changes in iris recognition performance due to the elapsed time between probe and gallery iris images, we examine the effect of elapsed time on iris recognition utilizing 7,628 iris images from 46 subjects with an average of ten visits acquired over two years from a legacy database at Clarkson University. Taken into consideration the impact of quality factors such as local contrast, illumination, blur and noise on iris recognition performance, regression models are built with and without quality metrics to evaluate the degradation of iris recognition performance based on time lapse factors. Our experimental results demonstrate the decrease of iris recognition performance along with increased elapsed time based on two iris recognition system (the modified Masek algorithm and a commercial software VeriEye SDK). These results also reveal the significance of quality factors in iris recognition regression indicating the variability in match scores. According to the regression analysis, our study in this paper helps provide the quantified decrease on match scores with increased elapsed time, which indicates the possibility to implement the prediction scheme for iris recognition performance based on learning of impact on time lapse factors.

  8. Very-High-Resolution Time-Lapse Photography for Plant and Ecosystems Research

    Directory of Open Access Journals (Sweden)

    Mary H. Nichols

    2013-09-01

    Full Text Available Premise of the study: Traditional photography is a compromise between image detail and area covered. We report a new method for creating time-lapse sequences of very-high-resolution photographs to produce zoomable images that facilitate observation across a range of spatial and temporal scales. Methods and Results: A robotic camera mount and software were used to capture images of the growth and movement in Brassica rapa every 15 s in the laboratory. The resultant time-lapse sequence (http://timemachine.gigapan.org/wiki/Plant_Growth captures growth detail such as circumnutation. A modified, solar-powered system was deployed at a remote field site in southern Arizona. Images were collected every 2 h over a 3-mo period to capture the response of vegetation to monsoon season rainfall (http://timemachine.gigapan.org/wiki/Arizona_Grasslands. Conclusions: A technique for observing time sequences of both individual plant and ecosystem response at a range of spatial scales is available for use in the laboratory and in the field.

  9. Informing hydrological models with ground-based time-lapse relative gravimetry: potential and limitations

    DEFF Research Database (Denmark)

    Bauer-Gottwein, Peter; Christiansen, Lars; Rosbjerg, Dan

    2011-01-01

    Coupled hydrogeophysical inversion emerges as an attractive option to improve the calibration and predictive capability of hydrological models. Recently, ground-based time-lapse relative gravity (TLRG) measurements have attracted increasing interest because there is a direct relationship between ...... in gravity due to unmonitored non-hydrological effects, and the requirement of a gravitationally stable reference station. Application of TLRG in hydrology should be combined with other geophysical and/or traditional monitoring methods.......Coupled hydrogeophysical inversion emerges as an attractive option to improve the calibration and predictive capability of hydrological models. Recently, ground-based time-lapse relative gravity (TLRG) measurements have attracted increasing interest because there is a direct relationship between...... the signal and the change in water mass stored in the subsurface. Thus, no petrophysical relationship is required for coupled hydrogeophysical inversion. Two hydrological events were monitored with TLRG. One was a natural flooding event in the periphery of the Okavango Delta, Botswana, and one was a forced...

  10. Time-lapse nanoscopy of friction in the non-Amontons and non-Coulomb regime.

    Science.gov (United States)

    Ishida, Tadashi; Sato, Takaaki; Ishikawa, Takahiro; Oguma, Masatsugu; Itamura, Noriaki; Goda, Keisuke; Sasaki, Naruo; Fujita, Hiroyuki

    2015-03-11

    Originally discovered by Leonard da Vinci in the 15th century, the force of friction is directly proportional to the applied load (known as Amontons' first law of friction). Furthermore, kinetic friction is independent of the sliding speed (known as Coulomb's law of friction). These empirical laws break down at high normal pressure (due to plastic deformation) and low sliding speed (in the transition regime between static friction and kinetic friction). An important example of this phenomenon is friction between the asperities of tectonic plates on the Earth. Despite its significance, little is known about the detailed mechanism of friction in this regime due to the lack of experimental methods. Here we demonstrate in situ time-lapse nanoscopy of friction between asperities sliding at ultralow speed (∼0.01 nm/s) under high normal pressure (∼GPa). This is made possible by compressing and rubbing a pair of nanometer-scale crystalline silicon anvils with electrostatic microactuators and monitoring its dynamical evolution with a transmission electron microscope. Our analysis of the time-lapse movie indicates that superplastic behavior is induced by decrystallization, plastic deformation, and atomic diffusion at the asperity-asperity interface. The results hold great promise for a better understanding of quasi-static friction under high pressure for geoscience, materials science, and nanotechnology.

  11. Time Lapse Electrical Resistivity to Connect Evapotranspiration and Groundwater Fluxes in the Critical Zone

    Science.gov (United States)

    Jarvis, S. K.; Harmon, R. E.; Barnard, H. R.; Randall, J.; Singha, K.

    2017-12-01

    The critical zone (CZ)—an open system extending from canopy top to the base of groundwater—is a highly dynamic and heterogeneous environment. In forested terrain, trees make up a large component of the CZ. This work aims to quantify the connection between vegetation and subsurface water storage at a hillslope scale within a forested watershed in the H.J. Andrews Experimental Forest, Oregon. To identify the mechanism(s) controlling the connection at the hillslope scale, we observe patterns in electrical conductivity using 2D-time lapse-DC resistivity. To compare inversions through time a representative error model was determined using L-curve criterion. Inverted data show high spatial variability in ground electrical conductivity and variation at both diel and seasonal timescales. These changes are most pronounced in areas corresponding to dense vegetation. The diel pattern in electrical conductivity is also observed in monitored sap flow sensors, water-level gauges, tensiometers, and sediment thermal probes. To quantify the temporal connection between these data over the course of the growing season a cross correlation analysis was conducted. Preliminary data show that over the course of the growing season transpiration becomes decoupled from both groundwater and soil moisture. Further decomposition of the inverted time lapse data will highlight spatial variability in electrical conductivity providing insight into the where, when, and how(s) of tree-modified subsurface storage.

  12. Using a time lapse microgravity model for mapping seawater intrusion around Semarang

    Energy Technology Data Exchange (ETDEWEB)

    Supriyadi,, E-mail: supriyadi@mail.unnes.ac.id; Khumaedi [Physics Department, Semarang State University (UNNES), D7 Building 2nd Floor FMIPA Sekaran Gunungpati (Indonesia); Yusuf, M. [Badan Meteologi Klimatologi Goefisika (BMKG), Jl.Angkasa I No.2 Kemayoran Jakarta Pusat (Indonesia); Agung, W. [Physics Department, Diponegoro University (UNDIP), Jl. Prof. Soedharto, Tembalang, Semarang (Indonesia)

    2016-03-11

    A modeling of time-lapse microgravity anomaly due to sea water intrusion has been conducted. It used field data of aquifer cross section, aquifer thickness and lithology of research area. Those data were then processed using Grav3D and Surfer. Modeling results indicated that the intrusion of sea water resulting in a time-lapse microgravity anomalies of 0.12 to 0.18 mGal, at soil layer density of 0.15 g/cm{sup 3} to 0.3 g/cm{sup 3} and at depth of 30 to 100 m. These imply that the areas experiencing seawater intrusion were Tanjung Mas, SPBE Bandarharjo, Brass, Old Market Boom and Johar as the microgravity measured there were in the range of 0.12 to 0.18 mGal and the density contrast were at 0.15 g/cm{sup 3} to 0.28 g/cm{sup 3}. Areas that experienced fluid reduction were Puri Anjasmoro, Kenconowungu and Puspowarno with microgravity changes from -0.06 mGal to -0.18 mGal.

  13. Seismic site-response characterization of high-velocity sites using advanced geophysical techniques: application to the NAGRA-Net

    Science.gov (United States)

    Poggi, V.; Burjanek, J.; Michel, C.; Fäh, D.

    2017-08-01

    The Swiss Seismological Service (SED) has recently finalised the installation of ten new seismological broadband stations in northern Switzerland. The project was led in cooperation with the National Cooperative for the Disposal of Radioactive Waste (Nagra) and Swissnuclear to monitor micro seismicity at potential locations of nuclear-waste repositories. To further improve the quality and usability of the seismic recordings, an extensive characterization of the sites surrounding the installation area was performed following a standardised investigation protocol. State-of-the-art geophysical techniques have been used, including advanced active and passive seismic methods. The results of all analyses converged to the definition of a set of best-representative 1-D velocity profiles for each site, which are the input for the computation of engineering soil proxies (traveltime averaged velocity and quarter-wavelength parameters) and numerical amplification models. Computed site response is then validated through comparison with empirical site amplification, which is currently available for any station connected to the Swiss seismic networks. With the goal of a high-sensitivity network, most of the NAGRA stations have been installed on stiff-soil sites of rather high seismic velocity. Seismic characterization of such sites has always been considered challenging, due to lack of relevant velocity contrast and the large wavelengths required to investigate the frequency range of engineering interest. We describe how ambient vibration techniques can successfully be applied in these particular conditions, providing practical recommendations for best practice in seismic site characterization of high-velocity sites.

  14. Compositional trends among Kaapvaal Craton garnet peridotite xenoliths and their effects on seismic velocity and density

    DEFF Research Database (Denmark)

    Schutt, Derek; Lesher, Charles

    2010-01-01

    garnet and clinopyroxene enrichment. Using the parameterization of Schutt and Lesher (2006) we show that at cratonic mantle temperatures and pressures, orthopyroxene enrichment results in little change in bulk density (ρbulk) and shear-wave velocity (VS), but decreases compressional wave velocities (VP......We examine the modes and compositions of garnet-bearing peridotite xenoliths from the Kaapvaal Craton to quantify factors governing density and seismic velocity variations within metasomatically altered cratonic mantle. Three distinct compositional trends are resolved by principal component...... analysis. The first reflects differences in residue composition resulting from partial melting. The second is associated with orthopyroxene (opx) enrichment, possibly due to silica addition by subduction zone fluids in the source region of the xenoliths. The third principal component reflects garnet...

  15. Transformation of seismic velocity data to extract porosity and saturation values for rocks

    International Nuclear Information System (INIS)

    Berryman, James G.; Berge, Patricia A.; Bonner, Brian P.

    2000-01-01

    For wave propagation at low frequencies in a porous medium, the Gassmann-Domenico relations are well-established for homogeneous partial saturation by a liquid. They provide the correct relations for seismic velocities in terms of constituent bulk and shear moduli, solid and fluid densities, porosity and saturation. It has not been possible, however, to invert these relations easily to determine porosity and saturation when the seismic velocities are known. Also, the state (or distribution) of saturation, i.e., whether or not liquid and gas are homogeneously mixed in the pore space, is another important variable for reservoir evaluation. A reliable ability to determine the state of saturation from velocity data continues to be problematic. It is shown how transforming compressional and shear wave velocity data to the (ρ/λ,μ/λ)-plane (where λ and μ are the Lame parameters and ρ is the total density) results in a set of quasi-orthogonal coordinates for porosity and liquid saturation that greatly aids in the interpretation of seismic data for the physical parameters of most interest. A second transformation of the same data then permits isolation of the liquid saturation value, and also provides some direct information about the state of saturation. By thus replotting the data in the (λ/μ, ρ/μ)-plane, inferences can be made concerning the degree of patchy (inhomogeneous) versus homogeneous saturation that is present in the region of the medium sampled by the data. Our examples include igneous and sedimentary rocks, as well as man-made porous materials. These results have potential applications in various areas of interest, including petroleum exploration and reservoir characterization, geothermal resource evaluation, environmental restoration monitoring, and geotechnical site characterization. (c) 2000 Acoustical Society of America

  16. Regional velocity structure in northern California from inversion of scattered seismic surface waves

    Science.gov (United States)

    Pollitz, Fred F.

    1999-07-01

    Seismic surface waves recorded by the Berkeley Digital Seismic Network have been analyzed in order to constrain three-dimensional lateral heterogeneity of the upper mantle under northern California. A total of 2164 seismograms from 173 teleseismic events were windowed for the fundamental mode Rayleigh wave, followed by estimation of complex amplitude spectra over the period range 16 to 100 s using a multiple-taper method. Since Rayleigh waves at shorter periods, particularly below 35 s, suffer from serious multipathing or "non-plane" wave arrivals, these amplitude spectra have been interpreted as the product of wavefront distortion along the teleseismic propagation path and seismic structure beneath the network. The amplitude spectra are first modeled in terms of non-plane incoming wavefields and structural phase velocity perturbations period by period. After corrections for Moho and surface topography, the phase velocity maps are inverted for three-dimensional shear velocity perturbations δνs down to a depth of 200 km. The δνs maps are in good agreement with the results of body studies over a broad spatial scale. The dominant signals are associated with the thermal effects of the active Gorda and fossil Farallon subducted slab stretching from Mount Shasta through the western Sierran foothills to the southern Great Valley and asthenospheric upwelling beneath the northern Coast Ranges. The southern Sierra Nevada Range is characterized by fast δνs down to ˜50 km and slow velocities between ˜60 and 120 km depth, in agreement with independent inferences of a cold crust and warm upper mantle, which may provide the buoyancy forces necessary to support the elevation of the range.

  17. Seismic velocity structure at a gas hydrate reflector, offshore western Colombia, from full waveform inversion

    Science.gov (United States)

    Minshull, T. A.; Singh, S. C.; Westbrook, G. K.

    1994-03-01

    Seismic reflection profiles across many continental margins have imaged bottom simulating reflectors (BSRs), which have been interpreted as being formed at the base of a methane hydrate stability field. Such reflectors might arise either from an impedance contrast between high-velocity, partially hydrated sediments and water-saturated sediments or from a contrast with partially gas-saturated sediments. These alternatives may be hard to distinguish by conventional amplitude-versus-offset or waveform modeling approaches. Here, we investigate the origin of a high amplitude BSR in the accretionary wedge offshore of western Colombia by seismic waveform inversion. The inversion procedure consists of three steps: firstly, determination of root-mean-square velocities and hence estimates of the interval velocities between major reflectors by a global grid search for maximum normalized energy along elliptical trajectories in the intercept time-slowness domain; secondly, determination of accurate interval velocities between these reflectors by a Monte Carlo search for maximum energy; and thirdly, a waveform fit in the frequency-slowness domain, using differential reflectivity seismograms and a conjugate-gradient optimization algorithm to minimize the sample-by-sample waveform misfit between data and synthetic. At two locations, near a structural high, we find an approximately 30-m thick low-velocity zone beneath the BSR, with the properties of a partially gas-saturated zone, while at a third location, where the BSR amplitude is lower, we find no evidence for anomalously low velocities. The preferential development of the BSR in structures that would tend to intercept fluid flow or migrating gas and the presence of free gas beneath the BSR indicate a mechanism of BSR formation in which free methane gas migrates upward into the hydrate stability field or is carried there in advecting pore water.

  18. Shear-wave velocity-based probabilistic and deterministic assessment of seismic soil liquefaction potential

    Science.gov (United States)

    Kayen, R.; Moss, R.E.S.; Thompson, E.M.; Seed, R.B.; Cetin, K.O.; Der Kiureghian, A.; Tanaka, Y.; Tokimatsu, K.

    2013-01-01

    Shear-wave velocity (Vs) offers a means to determine the seismic resistance of soil to liquefaction by a fundamental soil property. This paper presents the results of an 11-year international project to gather new Vs site data and develop probabilistic correlations for seismic soil liquefaction occurrence. Toward that objective, shear-wave velocity test sites were identified, and measurements made for 301 new liquefaction field case histories in China, Japan, Taiwan, Greece, and the United States over a decade. The majority of these new case histories reoccupy those previously investigated by penetration testing. These new data are combined with previously published case histories to build a global catalog of 422 case histories of Vs liquefaction performance. Bayesian regression and structural reliability methods facilitate a probabilistic treatment of the Vs catalog for performance-based engineering applications. Where possible, uncertainties of the variables comprising both the seismic demand and the soil capacity were estimated and included in the analysis, resulting in greatly reduced overall model uncertainty relative to previous studies. The presented data set and probabilistic analysis also help resolve the ancillary issues of adjustment for soil fines content and magnitude scaling factors.

  19. Seismic velocity tomography for CO2 monitor in subsurface geological structures

    Directory of Open Access Journals (Sweden)

    Wasiu O. Raji

    2018-01-01

    Full Text Available The storage of CO2 in depleted hydrocarbon reservoirs and saline water aquifers is a leading solution to Global Warming due to CO2 emission to the atmosphere. The capture of CO2 from major CO2-emitting plants and its storage in underground geological structures has a potential to reduce Global Warming by about 60%. A procedure for monitoring safe and secure storage of CO2 in underground geological structures is demonstrated in this study using seismic velocity tomography. The tomographic method uses first arrival traveltime to estimate velocity of geological structure along the ray path. The inversion procedure utilizes optimized objective function that consists of two parts: (i a part that minimizes the misfit between the observed and inverted data, and (ii a part that enforces the true shape and structure of the real geology. First, the method is applied to invert the velocity structure of a west Texas oilfield, and later to reconstruct the velocity structure of Marmousi models before and after CO2 injection. The results of the tests confirm the appropriateness of the procedure for CO2 monitoring. The inverted velocity tomogram for the post-injection stage shows velocity perturbation due to CO2 presence and the progression in CO2 front. Technology for monitoring CO2 in geological storages as demonstrated in this study is crucial to forestall CO2 leakages and its negative consequences on the environment.

  20. Precise seismic-wave velocity atop Earth's core: No evidence for outer-core stratification

    Science.gov (United States)

    Alexandrakis, Catherine; Eaton, David W.

    2010-05-01

    Earth's outer core is composed of liquid Fe and Ni alloyed with a ˜10% fraction of light elements such as O, S, or Si. Secular cooling and compositional buoyancy drive vigorous convection that sustains the geodynamo, but critical details of light-element composition and thermal regime remain uncertain. Seismic velocities can provide important observational constraints on these parameters, but global reference models such as Preliminary Reference Earth Model ( PREM), IASP91 and AK135 exhibit significant discrepancies in the outermost ˜200 km of the core. Here, we apply an Empirical Transfer Function method to obtain precise arrival times for SmKS waves, a whispering-gallery mode that propagates near the underside of the core-mantle boundary. Models that fit our data are all characterized by seismic velocities and depth gradients in the outermost 200 km of the core that correspond best with PREM. This similarity to PREM, which has a smooth velocity profile that satisfies the adiabatic Adams and Williamson equation, argues against the presence of an anomalous layer of light material near the top of the core as suggested in some previous studies. A new model, AE09, is proposed as a slight modification to PREM for use as a reference model of the outermost core.

  1. Estimation of changes in saturation and pressure from 4D seismic AVO and time-shift analysis

    NARCIS (Netherlands)

    Trani, M.; Arts, R.; Leeuwenburgh, O.; Brouwer, J.

    2011-01-01

    A reliable estimate of reservoir pressure and fluid saturation changes from time-lapse seismic data is difficult to obtain. Existing methods generally suffer from leakage between the estimated parameters. We propose a new method using different combinations of time-lapse seismic attributes based on

  2. Elastic Velocity Updating through Image-Domain Tomographic Inversion of Passive Seismic Data

    Science.gov (United States)

    Witten, B.; Shragge, J. C.

    2014-12-01

    Seismic monitoring at injection sites (e.g., CO2sequestration, waste water disposal, hydraulic fracturing) has become an increasingly important tool for hazard identification and avoidance. The information obtained from this data is often limited to seismic event properties (e.g., location, approximate time, moment tensor), the accuracy of which greatly depends on the estimated elastic velocity models. However, creating accurate velocity models from passive array data remains a challenging problem. Common techniques rely on picking arrivals or matching waveforms requiring high signal-to-noise data that is often not available for the magnitude earthquakes observed over injection sites. We present a new method for obtaining elastic velocity information from earthquakes though full-wavefield wave-equation imaging and adjoint-state tomography. The technique exploits images of the earthquake source using various imaging conditions based upon the P- and S-wavefield data. We generate image volumes by back propagating data through initial models and then applying a correlation-based imaging condition. We use the P-wavefield autocorrelation, S-wavefield autocorrelation, and P-S wavefield cross-correlation images. Inconsistencies in the images form the residuals, which are used to update the P- and S-wave velocity models through adjoint-state tomography. Because the image volumes are constructed from all trace data, the signal-to-noise in this space is increased when compared to the individual traces. Moreover, it eliminates the need for picking and does not require any estimation of the source location and timing. Initial tests show that with reasonable source distribution and acquisition array, velocity anomalies can be recovered. Future tests will apply this methodology to other scales from laboratory to global.

  3. Near Surface Seismic Hazard Characterization in the Presence of High Velocity Contrasts

    Science.gov (United States)

    Gribler, G.; Mikesell, D.; Liberty, L. M.

    2017-12-01

    We present new multicomponent surface wave processing techniques that provide accurate characterization of near-surface conditions in the presence of large lateral or vertical shear wave velocity boundaries. A common problem with vertical component Rayleigh wave analysis in the presence of high contrast subsurface conditions is Rayleigh wave propagation mode misidentification due to an overlap of frequency-phase velocity domain dispersion, leading to an overestimate of shear wave velocities. By using the vertical and horizontal inline component signals, we isolate retrograde and prograde particle motions to separate fundamental and higher mode signals, leading to more accurate and confident dispersion curve picks and shear wave velocity estimates. Shallow, high impedance scenarios, such as the case with shallow bedrock, are poorly constrained when using surface wave dispersion information alone. By using a joint inversion of dispersion and horizontal-to-vertical (H/V) curves within active source frequency ranges (down to 3 Hz), we can accurately estimate the depth to high impedance boundaries, a significant improvement compared to the estimates based on dispersion information alone. We compare our approach to body wave results that show comparable estimates of bedrock topography. For lateral velocity contrasts, we observe horizontal polarization of Rayleigh waves identified by an increase in amplitude and broadening of the horizontal spectra with little variation in the vertical component spectra. The horizontal spectra offer a means to identify and map near surface faults where there is no topographic or clear body wave expression. With these new multicomponent active source seismic data processing and inversion techniques, we better constrain a variety of near surface conditions critical to the estimation of local site response and seismic hazards.

  4. Time-lapse cinematography in living Drosophila tissues: preparation of material.

    Science.gov (United States)

    Davis, Ilan; Parton, Richard M

    2006-11-01

    The fruit fly, Drosophila melanogaster, has been an extraordinarily successful model organism for studying the genetic basis of development and evolution. It is arguably the best-understood complex multicellular model system, owing its success to many factors. Recent developments in imaging techniques, in particular sophisticated fluorescence microscopy methods and equipment, now allow cellular events to be studied at high resolution in living material. This ability has enabled the study of features that tend to be lost or damaged by fixation, such as transient or dynamic events. Although many of the techniques of live cell imaging in Drosophila are shared with the greater community of cell biologists working on other model systems, studying living fly tissues presents unique difficulties in keeping the cells alive, introducing fluorescent probes, and imaging through thick hazy cytoplasm. This protocol outlines the preparation of major tissue types amenable to study by time-lapse cinematography and different methods for keeping them alive.

  5. Time-lapse cinematography of dynamic changes occurring during in vitro development of human embryos.

    Science.gov (United States)

    Mio, Yasuyuki; Maeda, Kazuo

    2008-12-01

    The purpose of this study was to clarify developmental changes of early human embryos by using time-lapse cinematography (TLC). For human ova, fertilization and cleavage, development of the blastocyst, and hatching, as well as consequent changes were repeatedly photographed at intervals of 5-6 days by using an inverse microscope under stabilized temperature and pH. Photographs were taken at 30 frames per second and the movies were studied. Cinematography has increased our understanding of the morphologic mechanisms of fertilization, development, and behavior of early human embryos, and has identified the increased risk of monozygotic twin pregnancy based on prolonged incubation in vitro to the blastocyst stage. Using TLC, we observed the fertilization of an ovum by a single spermatozoon, followed by early cleavages, formation of the morula, blastocyst hatching, changes in the embryonic plates, and the development of monozygotic twins from the incubated blastocysts.

  6. Time-lapse cinematography of the capillary tube cell migration inhibition test.

    Science.gov (United States)

    Bray, M A

    1980-01-01

    The kinetics of human and guinea pig cell migration inhibition have been studied using time-lapse cinematography of cells migrating from capillary tubes. Guinea pig and human cells exhibit markedly different kinetics in the absence of inhibitors. Specific antigen causes a dose-related inhibition of migration for up to 60 h using guinea pig cells and a peak of inhibition after 18 h using the human leucocyte system. The timing of measurement of maximum activity more critical for the latter test. The kinetics of lymphokine generation have been examined and the migration inhibitory activity of the plant mitogen (PHA), a Kurloff cell product and a continuous cell line supernatant have been compared with the inhibitory profiles of lymphokine preparations and specific antigen.

  7. Slow speed—fast motion: time-lapse recordings in physics education

    Science.gov (United States)

    Vollmer, Michael; Möllmann, Klaus-Peter

    2018-05-01

    Video analysis with a 30 Hz frame rate is the standard tool in physics education. The development of affordable high-speed-cameras has extended the capabilities of the tool for much smaller time scales to the 1 ms range, using frame rates of typically up to 1000 frames s-1, allowing us to study transient physics phenomena happening too fast for the naked eye. Here we want to extend the range of phenomena which may be studied by video analysis in the opposite direction by focusing on much longer time scales ranging from minutes, hours to many days or even months. We discuss this time-lapse method, needed equipment and give a few hints of how to produce respective recordings for two specific experiments.

  8. Automated Tracking of Root for Confocal Time-lapse Imaging of Cellular Processes.

    Science.gov (United States)

    Doumane, Mehdi; Lionnet, Claire; Bayle, Vincent; Jaillais, Yvon; Caillaud, Marie-Cécile

    2017-04-20

    Here we describe a protocol that enables to automatically perform time-lapse imaging of growing root tips for several hours. Plants roots expressing fluorescent proteins or stained with dyes are imaged while they grow using automatic movement of the microscope stage that compensates for root growth and allows to follow a given region of the root over time. The protocol makes possible the image acquisition of multiple growing root tips, therefore increasing the number of recorded mitotic events in a given experiment. The protocol also allows the visualization of more than one fluorescent protein or dye simultaneously, using multiple channel acquisition. We particularly focus on imaging of cytokinesis in Arabidopsis root tip meristem, but this protocol is also suitable to follow root hair growth, pollen tube growth, and other regions of root over time, in various plant species. It may as well be amendable to automatically track non-plant structures with an apical growth.

  9. 3-D time-lapse electrical resistivity monitoring of injected CO2 in a shallow aquifer

    DEFF Research Database (Denmark)

    Doetsch, Joseph A. J.A.; Auken, Esben; Christiansen, Anders Vest C A.V.C.

    2013-01-01

    Contamination of potable groundwater by leaking CO2 is a potential risk of carbon sequestration. With the help of a field experiment, we investigate if surface electrical resistivity tomography (ERT) can detect dissolved CO2 in a shallow aquifer. For this purpose, we injected CO2 at a depth of 5...... inversion reveals the geology at the site consisting of aeolian sands near the surface and glacial sands below 5 m depth. Time-lapse inversions clearly image the dissolved CO2 plume with decreased electrical resistivity values. We can follow the CO2 plume as it spreads and moves with the groundwater...... and 10 m and monitored its migration using 320 surface electrodes on a 126 m × 20 m grid. A fully automated acquisition system continuously collected data and uploaded it into an online database. The large amount of data allows for time-series analysis for data quality and noise estimation. A baseline...

  10. How does blastomere removal affect embryonic development? : A time-lapse analysis

    DEFF Research Database (Denmark)

    Kirkegaard, Kirstine; Hindkjær, Johnny Juhl; Ingerslev, Hans Jakob

    Introduction: Preimplantation genetic diagnosis (PGD) is offered to couples whose potential offspring are at risk of an inherited single gene disease or structural chromosomal disorder. PGD requires embryonic DNA for establishing the diagnosis, which can be obtained by performing blastomere biopsy...... of the 6-10 cell embryo. It has been argued that blastomere removal does not affect embryonic development, but few studies have focussed on safety of the procedure. Recently, time-lapse studies on mice have suggested that blastomere removal affects embryonic development. The present study was conducted...... at the same time-point as the control group, but had a significantly smaller size (p=0,000) and a thicker zona pellucida (p=0,000) when hatching. In the control group expansion of the blastocyst caused continous thinning of zona pellucida until the blastocyst hatched. In the biopsed group no expansion or zona...

  11. Optimal Estimation of Diffusion Coefficients from Noisy Time-Lapse-Recorded Single-Particle Trajectories

    DEFF Research Database (Denmark)

    Vestergaard, Christian Lyngby

    2012-01-01

    Optimal Estimation of Diusion Coecients from Noisy Time-Lapse- Measurements of Single-Particle Trajectories Single-particle tracking techniques allow quantitative measurements of diusion at the single-molecule level. Recorded time-series are mostly short and contain considerable measurement noise....... The standard method for estimating diusion coecients from single-particle trajectories is based on leastsquares tting to the experimentally measured mean square displacements. This method is highly inecient, since it ignores the high correlations inherent in these. We derive the exact maximum likelihood...... parameter values. We extend the methods to particles diusing on a uctuating substrate, e.g., exible or semi exible polymers such as DNA, and show that uctuations induce an important bias in the estimates of diusion coecients if they are not accounted for. We apply the methods to obtain precise estimates...

  12. Time-lapse reveals that osteoclasts can move across the bone surface while resorbing

    DEFF Research Database (Denmark)

    Søe, Kent; Delaissé, Jean-Marie

    2017-01-01

    resulting in the formation of clusters of round pits. However, very importantly, we also demonstrate that more than half of the osteoclasts moved laterally, displacing their extracellular bone-resorbing compartment over the bone surface without disassembling and reconstructing it, thereby generating long......Bone erosion both demands that the osteoclast resorbs bone matrix and moves over the bone surface. It is widely accepted that these two activities alternate, because they are considered mutually exclusive since resorption is believed to involve an immobilizing seal to the bone surface. However......, clear real-time observations are still lacking. Herein, we used specific markers and time-lapse to monitor live the spatiotemporal generation of resorption events by osteoclasts cultured on bone slices. In accordance with the current view, we found alternating episodes of resorption and migration...

  13. A poly(dimethylsiloxane)-based device enabling time-lapse imaging with high spatial resolution

    International Nuclear Information System (INIS)

    Hirano, Masahiko; Hoshida, Tetsushi; Sakaue-Sawano, Asako; Miyawaki, Atsushi

    2010-01-01

    We have developed a regulator-free device that enables long-term incubation of mammalian cells for epi-fluorescence imaging, based on a concept that the size of sample to be gassed and heated is reduced to observation scale. A poly(dimethylsiloxane) block stamped on a coverslip works as a long-lasting supplier of CO 2 -rich gas to adjust bicarbonate-containing medium in a tiny chamber at physiological pH, and an oil-immersion objective warms cells across the coverslip. A time-lapse imaging experiment using HeLa cells stably expressing fluorescent cell-cycle indicators showed that the cells in the chamber proliferated with normal cell-cycle period over 2 days.

  14. Rapid antimicrobial susceptibility testing of clinical isolates by digital time-lapse microscopy

    DEFF Research Database (Denmark)

    Fredborg, M; Rosenvinge, F S; Spillum, E

    2015-01-01

    (168 antimicrobial agent-organism combinations) demonstrated 3.6 % minor, no major and 1.2 % very major errors of the oCelloScope system compared to conventional susceptibility testing, as well as a rapid and correct phenotypic detection of strains with methicillin-resistant Staphylococcus aureus (MRSA......Rapid antimicrobial susceptibility testing (AST) is essential for early and appropriate therapy. Methods with short detection time enabling same-day treatment optimisation are highly favourable. In this study, we evaluated the potential of a digital time-lapse microscope system, the o......CelloScope system, to perform rapid AST. The oCelloScope system demonstrated a very high accuracy (96 % overall agreement) when determining the resistance profiles of four reference strains, nine clinical isolates, including multi-drug-resistant isolates, and three positive blood cultures. AST of clinical isolates...

  15. Network Flow Integer Programming to Track Elliptical Cells in Time-Lapse Sequences.

    Science.gov (United States)

    Turetken, Engin; Wang, Xinchao; Becker, Carlos J; Haubold, Carsten; Fua, Pascal

    2017-04-01

    We propose a novel approach to automatically tracking elliptical cell populations in time-lapse image sequences. Given an initial segmentation, we account for partial occlusions and overlaps by generating an over-complete set of competing detection hypotheses. To this end, we fit ellipses to portions of the initial regions and build a hierarchy of ellipses, which are then treated as cell candidates. We then select temporally consistent ones by solving to optimality an integer program with only one type of flow variables. This eliminates the need for heuristics to handle missed detections due to partial occlusions and complex morphology. We demonstrate the effectiveness of our approach on a range of challenging sequences consisting of clumped cells and show that it outperforms state-of-the-art techniques.

  16. Development of a State-Wide 3-D Seismic Tomography Velocity Model for California

    Science.gov (United States)

    Thurber, C. H.; Lin, G.; Zhang, H.; Hauksson, E.; Shearer, P.; Waldhauser, F.; Hardebeck, J.; Brocher, T.

    2007-12-01

    We report on progress towards the development of a state-wide tomographic model of the P-wave velocity for the crust and uppermost mantle of California. The dataset combines first arrival times from earthquakes and quarry blasts recorded on regional network stations and travel times of first arrivals from explosions and airguns recorded on profile receivers and network stations. The principal active-source datasets are Geysers-San Pablo Bay, Imperial Valley, Livermore, W. Mojave, Gilroy-Coyote Lake, Shasta region, Great Valley, Morro Bay, Mono Craters-Long Valley, PACE, S. Sierras, LARSE 1 and 2, Loma Prieta, BASIX, San Francisco Peninsula and Parkfield. Our beta-version model is coarse (uniform 30 km horizontal and variable vertical gridding) but is able to image the principal features in previous separate regional models for northern and southern California, such as the high-velocity subducting Gorda Plate, upper to middle crustal velocity highs beneath the Sierra Nevada and much of the Coast Ranges, the deep low-velocity basins of the Great Valley, Ventura, and Los Angeles, and a high- velocity body in the lower crust underlying the Great Valley. The new state-wide model has improved areal coverage compared to the previous models, and extends to greater depth due to the data at large epicentral distances. We plan a series of steps to improve the model. We are enlarging and calibrating the active-source dataset as we obtain additional picks from investigators and perform quality control analyses on the existing and new picks. We will also be adding data from more quarry blasts, mainly in northern California, following an identification and calibration procedure similar to Lin et al. (2006). Composite event construction (Lin et al., in press) will be carried out for northern California for use in conventional tomography. A major contribution of the state-wide model is the identification of earthquakes yielding arrival times at both the Northern California Seismic

  17. Comparison of Effective Medium Schemes For Seismic Velocities in Cracked Anisotropic Rock

    Science.gov (United States)

    Morshed, S.; Chesnokov, E.

    2017-12-01

    Understanding of elastic properties of reservoir rock is necessary for meaningful interpretation and analysis of seismic measurements. The elastic properties of a rock are controlled by the microstructural properties such as mineralogical composition, pore and crack distribution, texture and pore connectivity. However, seismic scale is much larger than microstructure scale. Understanding of macroscopic properties at relevant seismic scale (e.g. borehole sonic data) comes from effective medium theory (EMT). However, most of the effective medium theories fail at high crack density as the interactions of strain fields of the cracks can't be ignored. We compare major EMT schemes from low to high crack density. While at low crack density all method gives similar results, at high crack density they differ significantly. Then, we focus on generalized singular approximation (GSA) and effective field (EF) method as they allow cracks beyond the limit of dilute concentrations. Additionally, we use grain contact (GC) method to examine the stiffness constants of the rock matrix. We prepare simple models of a multiphase media containing low to high concentrations of isolated pores. Randomly oriented spherical pores and horizontally oriented ellipsoidal (aspect ratio =0.1) pores have been considered. For isolated spherical pores, all the three methods show exactly same or similar results. However, inclusion interactions are different in different directions in case of horizontal ellipsoidal pores and individual stiffness constants differ greatly from one method to another at different crack density. Stiffness constants remain consistent in GSA method whereas some components become unusual in EF method at a higher crack density (>0.15). Finally, we applied GSA method to interpret ultrasonic velocities of core samples. Mineralogical composition from X-ray diffraction (XRD) data and lab measured porosity data have been utilized. Both compressional and shear wave velocities from GSA

  18. Observing and Modeling Temporal Variations of Seismic Velocities at the Geysers Geothermal Field, California

    Science.gov (United States)

    Lai, V. H.; Tsai, V. C.; Taira, T.

    2016-12-01

    Perturbations in subsurface elastic parameters induce changes in seismic velocity. To understand the stress perturbations due to geothermal operation, we apply seismic noise interferometry to examine the temporal variations of seismic velocity (dv/v) at the Geysers Geothermal Field, California. Our observations show a strong positive correlation between dv/v and net production (steam production minus fluid injection), and a strong negative correlation between dv/v and fluid injection. Notably, there is little time lag (less than a month) between dv/v and fluid injection in the SE region of the field, suggesting a rapid response in elastic properties in this highly saturated region. The influx of fluid decreases the effective shear modulus, which in turn decreases the velocities. A number of hypotheses have been suggested to cause stress perturbations in the field, including poroelastic-induced stresses, direct elastic loading and thermoelastic-induced stresses. We perform a 1-D hydrological simulation to calculate the expected variations in dv/v due to different stresses by considering Murnaghan's theory of finite deformations and the third-order terms in the strain energy function. The synthetic dv/v measurements are spatially averaged based on computed sensitivity kernels, allowing for direct comparison with both the amplitude and phase of dv/v observations. We show the order-of-magnitude effect that each of the stresses have on the dv/v measurement, and explore the possibility of using dv/v to constrain important hydrological and elastic properties such as hydraulic conductivity in the field.

  19. Time-lapse Ground-Penetrating Radar for Deriving Soil Hydraulic Properties

    Science.gov (United States)

    Klenk, Patrick; Jaumann, Stefan; Roth, Kurt

    2014-05-01

    A profound understanding of subsurface hydrological processes demands a detailed description of hydraulic parameter distributions at the pertinent scale of interest. However, characterizing soil hydraulic properties remains a challenge, especially for field scale studies. Accurate high-resolution GPR measurements of soil water dynamics have shown promise to alleviate this challenge. In recent years, ASSESS-GPR, a field scale test site for advancing Ground-Penetrating Radar methods has been successfully established in Heidelberg (e.g., Buchner et al, 2012 or Klenk, 2012). Permanently installed TDR sensor profiles allow for an independent, corroborating dataset which can serve as basis for hydrologic modeling. In such a well-controlled experimental setup, we can achieve a very high relative precision for non-invasively monitoring soil water dynamics with GPR (Klenk, 2012). We can furthermore study the dynamics of the capillary fringe in different materials through time-lapse GPR measurements during pumping experiments. For example, as Dagenbach et al (2013) have shown, information can be gained about the appropriate form of a hydraulic parameterization. We here expand on these previous works by presenting a set of experiments, where the water table has been raised and subsequently lowered in a multi-step fashion over the course of several days. We discuss the non-invasive, high-resolution monitoring of the corresponding subsurface water dynamics by time-lapse GPR and thoroughly assess potentials for deriving hydraulic parameters for the different materials through electromagnetic modeling of the GPR response for said materials under the measured forcing.

  20. Relative Morphokinetics Assessed by Time-Lapse Imaging Are Altered in Embryos From Patients With Endometriosis.

    Science.gov (United States)

    Freis, Alexander; Dietrich, Jens Erik; Binder, Moritz; Holschbach, Verena; Strowitzki, Thomas; Germeyer, Ariane

    2017-01-01

    Time-lapse technology allows almost continuous noninvasive assessment of embryonic development. It was shown previously that relative kinetics defining cleavage synchronicity are better predictors of blastocyst quality than absolute time points. This study aims to compare relative kinetics in embryos from patients with and without endometriosis. Time-lapse data were collected retrospectively from 596 patients undergoing infertility treatment for in vitro fertilization from January 2011 to July 2016. Four hundred twenty-eight patients with confounding comorbidities (ie, polycystic ovary syndrome, pathological spermiogram in the included cycle, numerical/structural genetic abnormalities, preimplantation genetic screening performed) or incomplete data sets were excluded. Of the 168 included patients, 72 (42.9%) had endometriosis. Indications for in vitro fertilization of controls were tubal factor, unexplained infertility, or prolonged infertility. Relative kinetics were calculated as defined previously: cleavage synchronicity (CS)2-8=((t3-t2) + (t5-t4))/(t8-t2), CS4-8=(t8-t5)/(t8-t4), CS2-4=(t4-t3)/(t4-t2), DNA replication time ratio (DR)=(t3-t2)/(t5-t3). In women with more than one embryo, the median time was analyzed. Median age, body mass index, smoking status, and AMH levels were similar in both groups. Embryos from patients with endometriosis showed poorer relative kinetics. The relative time CS2-8 was decreased in embryos from patients with endometriosis (0.7 [0.0-0.93] vs 0.8 [0.0-0.94], P relative kinetic parameters (CS2-4 and DR) were not significantly different. Embryos from patients with endometriosis presented with altered relative kinetics suggesting poorer embryo quality. These findings support recently published data demonstrating reduced oocyte quality in patients with endometriosis which is one possible explanation for their poor response to fertility treatment.

  1. Gliding motility of Babesia bovis merozoites visualized by time-lapse video microscopy.

    Directory of Open Access Journals (Sweden)

    Masahito Asada

    Full Text Available BACKGROUND: Babesia bovis is an apicomplexan intraerythrocytic protozoan parasite that induces babesiosis in cattle after transmission by ticks. During specific stages of the apicomplexan parasite lifecycle, such as the sporozoites of Plasmodium falciparum and tachyzoites of Toxoplasma gondii, host cells are targeted for invasion using a unique, active process termed "gliding motility". However, it is not thoroughly understood how the merozoites of B. bovis target and invade host red blood cells (RBCs, and gliding motility has so far not been observed in the parasite. METHODOLOGY/PRINCIPAL FINDINGS: Gliding motility of B. bovis merozoites was revealed by time-lapse video microscopy. The recorded images revealed that the process included egress of the merozoites from the infected RBC, gliding motility, and subsequent invasion into new RBCs. The gliding motility of B. bovis merozoites was similar to the helical gliding of Toxoplasma tachyzoites. The trails left by the merozoites were detected by indirect immunofluorescence assay using antiserum against B. bovis merozoite surface antigen 1. Inhibition of gliding motility by actin filament polymerization or depolymerization indicated that the gliding motility was driven by actomyosin dependent process. In addition, we revealed the timing of breakdown of the parasitophorous vacuole. Time-lapse image analysis of membrane-stained bovine RBCs showed formation and breakdown of the parasitophorous vacuole within ten minutes of invasion. CONCLUSIONS/SIGNIFICANCE: This is the first report of the gliding motility of B. bovis. Since merozoites of Plasmodium parasites do not glide on a substrate, the gliding motility of B. bovis merozoites is a notable finding.

  2. Evidence of depth dependence of the seismic velocity temporal change associated with the Wenchuan earthquake

    Science.gov (United States)

    Campillo, M.; Chen, J.; Froment, B.; Liu, Q.

    2009-12-01

    We used the vertical motions recorded during two years by a 159 broad band sensor network run by the Institute of Geology of the China Earthquake Administration to monitor the velocity changes associated with the M7.9 Wenchuan earthquake. We measured the velocity changes from ambient noise in different period bands. We cross-correlate 30-day moving windows of noise records for all the possible stations pairs and compare the correlations function using the doublet method. The relative velocity variation is deduced from the accurately measured delays for the different station pairs. We found a clear co-seismic change when considering the 1-3s and 3-8 sec. The spatial distribution of velocity change is discussed in a companion paper (Chen et al.). The amplitude of the relative change of velocity measured for a group of 22 stations in a range of 100 km around the fault is of the order of 6 10-4 for both period bands. Within the temporal resolution of our measurements, the change appears to coincide with the earthquake. If we assume that the wavefield consists mostly of Rayleigh waves, we expect our measurements to be characteristic of changes occurring in the upper crust. To investigate deeper process, we filtered the original data in the band 2-40s and increased the length of the moving window to 100 days. We found that the apparent velocity variation is of the same order as for the short period cases. The main difference with the short period result is that the peak of velocity decrease is not coincident with the earthquake but actually reaches its maximum about 100 days after the earthquake. We also filtered the original data in the band 8-30s and found that the apparent velocity variation is of the same order as for the short period cases but begins to be measurable only 100 days after the earthquake. This observation suggests a very different behavior for the ‘elastic’ upper crust and a lower crust subject to a more complex rheology as it was suggested from

  3. The thin section rock physics: Modeling and measurement of seismic wave velocity on the slice of carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Wardaya, P. D., E-mail: pongga.wardaya@utp.edu.my; Noh, K. A. B. M., E-mail: pongga.wardaya@utp.edu.my; Yusoff, W. I. B. W., E-mail: pongga.wardaya@utp.edu.my [Petroleum Geosciences Department, Universiti Teknologi PETRONAS, Tronoh, Perak, 31750 (Malaysia); Ridha, S. [Petroleum Engineering Department, Universiti Teknologi PETRONAS, Tronoh, Perak, 31750 (Malaysia); Nurhandoko, B. E. B. [Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Dept. of Physics, Institute of Technology Bandung, Bandung, Indonesia and Rock Fluid Imaging Lab, Bandung (Indonesia)

    2014-09-25

    This paper discusses a new approach for investigating the seismic wave velocity of rock, specifically carbonates, as affected by their pore structures. While the conventional routine of seismic velocity measurement highly depends on the extensive laboratory experiment, the proposed approach utilizes the digital rock physics view which lies on the numerical experiment. Thus, instead of using core sample, we use the thin section image of carbonate rock to measure the effective seismic wave velocity when travelling on it. In the numerical experiment, thin section images act as the medium on which wave propagation will be simulated. For the modeling, an advanced technique based on artificial neural network was employed for building the velocity and density profile, replacing image's RGB pixel value with the seismic velocity and density of each rock constituent. Then, ultrasonic wave was simulated to propagate in the thin section image by using finite difference time domain method, based on assumption of an acoustic-isotropic medium. Effective velocities were drawn from the recorded signal and being compared to the velocity modeling from Wyllie time average model and Kuster-Toksoz rock physics model. To perform the modeling, image analysis routines were undertaken for quantifying the pore aspect ratio that is assumed to represent the rocks pore structure. In addition, porosity and mineral fraction required for velocity modeling were also quantified by using integrated neural network and image analysis technique. It was found that the Kuster-Toksoz gives the closer prediction to the measured velocity as compared to the Wyllie time average model. We also conclude that Wyllie time average that does not incorporate the pore structure parameter deviates significantly for samples having more than 40% porosity. Utilizing this approach we found a good agreement between numerical experiment and theoretically derived rock physics model for estimating the effective seismic

  4. The thin section rock physics: Modeling and measurement of seismic wave velocity on the slice of carbonates

    International Nuclear Information System (INIS)

    Wardaya, P. D.; Noh, K. A. B. M.; Yusoff, W. I. B. W.; Ridha, S.; Nurhandoko, B. E. B.

    2014-01-01

    This paper discusses a new approach for investigating the seismic wave velocity of rock, specifically carbonates, as affected by their pore structures. While the conventional routine of seismic velocity measurement highly depends on the extensive laboratory experiment, the proposed approach utilizes the digital rock physics view which lies on the numerical experiment. Thus, instead of using core sample, we use the thin section image of carbonate rock to measure the effective seismic wave velocity when travelling on it. In the numerical experiment, thin section images act as the medium on which wave propagation will be simulated. For the modeling, an advanced technique based on artificial neural network was employed for building the velocity and density profile, replacing image's RGB pixel value with the seismic velocity and density of each rock constituent. Then, ultrasonic wave was simulated to propagate in the thin section image by using finite difference time domain method, based on assumption of an acoustic-isotropic medium. Effective velocities were drawn from the recorded signal and being compared to the velocity modeling from Wyllie time average model and Kuster-Toksoz rock physics model. To perform the modeling, image analysis routines were undertaken for quantifying the pore aspect ratio that is assumed to represent the rocks pore structure. In addition, porosity and mineral fraction required for velocity modeling were also quantified by using integrated neural network and image analysis technique. It was found that the Kuster-Toksoz gives the closer prediction to the measured velocity as compared to the Wyllie time average model. We also conclude that Wyllie time average that does not incorporate the pore structure parameter deviates significantly for samples having more than 40% porosity. Utilizing this approach we found a good agreement between numerical experiment and theoretically derived rock physics model for estimating the effective seismic wave

  5. 3D full-waveform inversion of time-lapse horizontal borehole GPR data to map soil water content variability

    Science.gov (United States)

    Klotzsche, A.; Van Der Kruk, J.; Oberroehrmann, M.; Vanderborght, J.; Vereecken, H.

    2015-12-01

    Soil moisture is a key state variable that controls water and mass fluxes in soil-plant systems and is variable in space and time. Over the last year's, hydrogeophysical methods such as ground penetrating radar (GPR) have been used to determine electromagnetic properties as proxies for soil water content (SWC). Here, we combined zero-offset-profiles (ZOP) GPR measurements within multiple horizontal minirhizotubes at different depths to determine the spatial and temporal variability of SWC under a winter wheat stand at the Selhausen test site (Germany). We studied spatio-temporal variations of SWC under three different treatments: rainfed, irrigated and sheltered. We acquired 15 time-lapse ZOP GPR dataset during the growing season of the wheat in the rhizotron facility using horizontal boreholes with a separation of 0.75m and a length of 6m at six depths between 0.1-1.2m. The obtained radar velocities were converted to SWC using the 4-phase volumetric complex refractive index model. SWC values obtained using standard ray-based processing methods were not reliable close to the surface (0.1-0.2m depth) because of the inference of the critically refracted air wave and the direct wave through the subsurface. Therefore, we implemented a full-waveform inversion that uses accurate 3D forward modeling of GPRMax that incorporates the air and soil interactions. The shuffled complex evolution (SCE) method allowed us to retrieve quantitative medium properties that explained the measured data with a R² of at least 0.95, and improved SWC estimates at all depths. The final SWC distributions for wet and dry conditions showed that the vertical variability is significantly larger than the lateral variability caused by strong influence of precipitation and irrigation events.

  6. Postseismic velocity changes following the 2010 Mw 7.1 Darfield earthquake, New Zealand, revealed by ambient seismic field analysis

    Science.gov (United States)

    Heckels, R. E. G.; Savage, M. K.; Townend, J.

    2018-01-01

    Quantifying seismic velocity changes following large earthquakes can provide insights into fault healing and reloading processes. This study presents temporal velocity changes detected following the September 2010 Mw 7.1 Darfield event in Canterbury, New Zealand. We use continuous waveform data from several temporary seismic networks lying on and surrounding the Greendale Fault, with a maximum inter-station distance of 156 km. Nine-component, day-long Green's functions were computed for frequencies between 0.1 and 1.0 Hz for continuous seismic records from immediately after the 4 September 2010 earthquake until 10 January 2011. Using the moving-window cross-spectral method seismic velocity changes were calculated. Over the study period, an increase in seismic velocity of 0.14 % ± 0.04 % was determined near the Greendale Fault, providing a new constraint on postseismic relaxation rates in the region. A depth analysis further showed that velocity changes were confined to the uppermost 5 km of the subsurface. We attribute the observed changes to postseismic relaxation via crack-healing of the Greendale Fault and throughout the surrounding region.

  7. Velocity Model Analysis Based on Integrated Well and Seismic Data of East Java Basin

    Science.gov (United States)

    Mubin, Fathul; Widya, Aviandy; Eka Nurcahya, Budi; Nurul Mahmudah, Erma; Purwaman, Indro; Radityo, Aryo; Shirly, Agung; Nurwani, Citra

    2018-03-01

    Time to depth conversion is an important processof seismic interpretationtoidentify hydrocarbonprospectivity. Main objectives of this research are to minimize the risk of error in geometry and time to depth conversion. Since it’s using a large amount of data and had been doing in the large scale of research areas, this research can be classified as a regional scale research. The research was focused on three horizons time interpretation: Top Kujung I, Top Ngimbang and Basement which located in the offshore and onshore areas of east Java basin. These three horizons was selected because they were assumed to be equivalent to the rock formation, which is it has always been the main objective of oil and gas exploration in the East Java Basin. As additional value, there was no previous works on velocity modeling for regional scale using geological parameters in East Java basin. Lithology and interval thickness were identified as geological factors that effected the velocity distribution in East Java Basin. Therefore, a three layer geological model was generated, which was defined by the type of lithology; carbonate (layer 1: Top Kujung I), shale (layer 2: Top Ngimbang) and Basement. A statistical method using three horizons is able to predict the velocity distribution on sparse well data in a regional scale. The average velocity range for Top Kujung I is 400 m/s - 6000 m/s, Top Ngimbang is 500 m/s - 8200 m/s and Basement is 600 m/s - 8000 m/s. Some velocity anomalies found in Madura sub-basin area, caused by geological factor which identified as thick shale deposit and high density values on shale. Result of velocity and depth modeling analysis can be used to define the volume range deterministically and to make geological models to prospect generation in details by geological concept.

  8. Finite-Frequency Seismic Imaging of Upper-Mantle Velocity Structures Beneath the South China Continent

    Science.gov (United States)

    Qu, P.; Chen, Y. J.; Yu, Y.

    2017-12-01

    South China Continent is major formed from the Paleo-South China plate. The continent has experienced complicated tectonic history after Neoproterozoic. Previous studies suggested some possible model for the collision between South China Continent and North China Continent. Body wave tomography and surface wave tomography are widely used to inverse upper mantle velocity structure. In our study, finite frequency tomography were carried on to get explanation more correctly. We gathered nearly 60000 pieces of teleseismic event records by 166 broad band seismic stations with Mw > 5.5. Here sensitive kernel of ak135 velocity structure was calculated, which is based on Born approximation, and then we applied multi-channel cross-correlation to pick arrival time difference under 3 frequency band. Combining with crust thickness correct from receiver function, we solve the inversion matrix by LSQR method, and get accurate upper mantle structure of P, S velocity. For more accurate results, we apply a method to calculate Vp/Vs ratio, to help to verify the velocity anomaly. The result in this research shows: 1. A strong velocity anomaly exists in the northern of South China Continent, in an area 31°N between 112°-118°E. The anomaly is about . We suggest that, this anomaly is related to the collision from North China Continent. It implies the collision underthrusted to southward. 2. A clearly slow velocity anomaly exists in the northern of Cathaysia block. This low velocity anomaly exist on the boundary of Yangtz block and Cathysian block, it is related to the left over of block collision in early phanerozoic. 3. We recognized some little velocity anomaly exit in the research area. Comparing these velocity anomaly with U-Pb zircon ages, we suggest complicated orogenesis in Phanerozoic is the cause of the formation of these little anomaly. The result in our study support the collision model, which shows the underthrust direction is southward, on the south of Qinling

  9. In-situ, time-lapse study of extracellular polymeric substance discharge in Streptococcus mutans biofilm.

    Science.gov (United States)

    Liu, Bernard Haochih; Yu, Li-Chieh

    2017-02-01

    Streptococcus mutans is one of the main pathogens that cause tooth decay. By metabolizing carbohydrates, S. mutans emits extracellular polymeric substance (EPS) that adheres to the tooth surface and forms layers of biofilm. Periodontal disease occurs due to the low pH environment created by S. mutans biofilm, and such an acidic environment gradually erodes tooth enamel. Since the existence of EPS is essential in the formation of biofilm, the in-situ investigation of its generation and distribution in real time is the key to the control and suppression of S. mutans biofilm. Prior studies of the biofilm formation process by fluorescence microscope, scanning electron microscope, or spectroscope have roughly divided the mechanism into three stages: (1) initial attachment; (2) microcolonies; and (3) maturation. However, these analytical methods are incapable to observe real-time changes in different locations of the extracellular matrix, and to analyze mechanical properties for single bacteria in micro and nanoscale. Since atomic force microscopy (AFM) operates by precise control of tip-sample interaction forces in liquid and in air, living microorganisms can be analyzed under near-physiological conditions. Thus, analytical techniques based on AFM constitute powerful tools for the study of biological samples, both qualitatively and quantitatively. In this study, we used AFM to quantitatively track the changes of multiple nanomechanical properties of S. mutans, including dissipation energy, adhesion force, deformation, and elastic modulus at different metabolic stages. The data revealed that the bacterial extracellular matrix has a gradient distribution in stickiness, in which different stickiness indicates the variation of EPS compositions, freshness, and metabolic stages. In-situ, time-lapse AFM images showed the local generation and distribution of EPS at different times, in which the highest adhesion distributed along sides of the S. mutans cells. Through time-lapse

  10. Integration of SH seismic reflection and Love-wave dispersion data for shear wave velocity determination over quick clays

    Science.gov (United States)

    Comina, Cesare; Krawczyk, Charlotte M.; Polom, Ulrich; Socco, Laura Valentina

    2017-09-01

    Quick clay is a water-saturated formation originally formed through flocculation and deposition in a marine to brackish environment. It is subsequently leached to low salinity by freshwater flow. If its strength decreases, then the flocculated structure collapses leading to landslides of varying destructiveness. Leaching can result in a reduction of the undisturbed shear strength of these clays and suggestions exist that a reduction in shear wave velocities is also possible. Integration of SH seismic reflection and Love-wave dispersion data was undertaken, in an area near the Göta River in southwest Sweden, to evaluate the potential of shear wave velocity imaging for detecting quick clays. Seismic reflection processing evidenced several geologically interesting interfaces related to the probable presence of quick clays (locally confirmed by boreholes) and sand-gravelly layers strongly contributing to water circulation within them. Dispersion data were extracted with a Gaussian windowing approach and inverted with a laterally constrained inversion using a priori information from the seismic reflection imaging. The inversion of dispersion curves has evidenced the presence of a low velocity layer (lvl, with a velocity reduction of ca. 30 per cent) probably associable to quick clays. This velocity reduction is enough to produce detectable phase-velocity differences in the field data and to achieve a better velocity resolution if compared to reflection seismic velocity analyses. The proposed approach has the potential of a comprehensive determination of the shear wave velocity distribution in the shallow subsurface. A sensitivity analysis of Love-wave dispersion data is also presented underlining that, despite limited dispersion of the data set and the velocity-reducing effect of quick-clay leaching, the proposed interpretation procedure arises as a valuable approach in quick clay and other lvl identification.

  11. Growth Rate and Morphology of a Single Calcium Carbonate Crystal on Polysulfone Film Measured with Time Lapse Raman Micro Spectroscopy

    NARCIS (Netherlands)

    Liszka, B.; Lenferink, Aufrid T.M.; Otto, Cornelis

    2016-01-01

    The growth of single, self- nucleated calcium carbonate crystals on a polysulfone (PSU) film was investigated with high resolution, time lapse Raman imaging. The Raman images were acquired on the interface of the polymer with the crystal. The growth of crystals could thus be followed in time. PSU is

  12. Mass conservative three-dimensional water tracer distribution from MCMC inversion of time-lapse GPR data

    NARCIS (Netherlands)

    Lalov, E.; Linde, N.; Vrugt, J.A.

    2012-01-01

    Time-lapse geophysical measurements are widely used to monitor the movement of water and solutes through the subsurface. Yet commonly used deterministic least squares inversions typically suffer from relatively poor mass recovery, spread overestimation, and limited ability to appropriately estimate

  13. Time-lapse micro-tomography analysis of the deformation response of a gellan-gum-based scaffold

    Czech Academy of Sciences Publication Activity Database

    Kytýř, Daniel; Fenclová, Nela; Zlámal, Petr; Kumpová, Ivana; Fíla, Tomáš; Koudelka_ml., Petr; Gantar, A.; Novak, S.

    2017-01-01

    Roč. 51, č. 3 (2017), s. 397-402 ISSN 1580-2949 Institutional support: RVO:68378297 Keywords : bone scaffold * gellan gum * time-lapse micro CT * digital volume correlation Subject RIV: JJ - Other Materials OBOR OECD: Materials engineering Impact factor: 0.436, year: 2016 http://mit.imt.si/Revija/izvodi/mit173/kytyr.pdf

  14. Seismic Wave Propagation from Underground Chemical Explosions: Sensitivity to Velocity and Thickness of a Weathered Layer

    Science.gov (United States)

    Hirakawa, E. T.; Ezzedine, S. M.

    2017-12-01

    Recorded motions from underground chemical explosions are complicated by long duration seismic coda as well as motion in the tangential direction. The inability to distinguish the origins of these complexities as either source or path effects comprises a limitation to effective monitoring of underground chemical explosions. With numerical models, it is possible to conduct rigorous sensitivity analyses for chemical explosive sources and their resulting ground motions under the influence of many attributes, including but not limited to complex velocity structure, topography, and non-linear source characteristics. Previously we found that topography can cause significant scattering in the direct wave but leads to relatively little motion in the coda. Here, we aim to investigate the contribution from the low-velocity weathered layer that exists in the shallow subsurface apart from and in combination with surface topography. We use SW4, an anelastic anisotropic fourth order finite difference code to simulate chemical explosive source in a 1D velocity structure consisting of a single weathered layer over a half space. A range of velocity magnitudes are used for the upper weathered layer with the velocities always being lower than that of the granitic underlaying layer. We find that for lower weathered layer velocities, the wave train is highly dispersed and causes a large percentage of energy to be contained in the coda in relation to the entire time series. The percentage of energy contained in the coda grows with distance from the source but saturates at a certain distance that depends on weathered layer velocity and thickness. The saturation onset distance increases with decreasing layer thickness and increasing velocity of the upper layer. Measurements of relative coda energy and coda saturation onset distance from real recordings can provide an additional constraint on the properties of the weathered layer in remote sites as well as test sites like the Nevada

  15. Distribution Of Seismic Velocity Change Associated With The May 12, 2008 M7.9 Wenchuan Earthquake

    Science.gov (United States)

    Chen, J.; Froment, B.; Liu, Q.; Campillo, M.

    2009-12-01

    We used continuous recordings in Sichuan, China to track the temporal evolution of the seismic velocity in a 2 year period which includes the great Wenchuan earthquake. The data are recorded by a temporary network of 84 out of 297 broad-band seismometers run by the Institute of Geology of the China Earthquake Administration. We analyzed the data from the stations in a 400*300km2 region that includes the southern 2/3 of the fault system activated during the Wenchuan event. We computed the cross correlation functions of seismic noise in a 30-day moving window for period between 1 and 3 seconds. We interpret them as an approximation of the actual Green function between the recorders. We then performed a doublet analysis to detect temporal changes of velocity with respect to a reference correlation. We deduce a relative average velocity change from the high quality delay measurements obtained for the ensemble of stations pairs. We found clear evidences that the seismic velocity drops after the earthquake by an average amount of about 0.1% in the fault region when measured with waves in the period range 1-3 seconds. We found that, according to our measurements, the velocity fluctuates within 0.02% in the months before the earthquake. The co-seismic variation is therefore well above the resolution of the measurements. We found that the co-seismic variation has similar amplitude for station groups in the Sichuan basin or in the Longmen Shan range, indicating that the co-seismic change is not fully controlled by the non-linear response of the shallow sediments. To investigate the velocity variations for different part in the region, we used a 0.5-degree station searching radius on 0.5°×0.5° grids to define sub-arrays, and measured the velocity variation for station pairs in the sub-arrays. We compared the measurements of velocity changes in different sub-arrays with a map of stress change deduced from a kinematic rupture model (Ji and Shao, personal communication) and

  16. Time-Lapse Monitoring of an Engineering Scaled Excavation at Federal District, Brazil by Passive Ambient NoiseInterferometry

    Science.gov (United States)

    Cárdenas-Soto, M., Sr.; Hussain, Y.; Martinez-Carvajal, H., Sr.; Martino, S., Sr.; Rocha, M., Sr.

    2016-12-01

    gave Rayleigh wave velocity changes (dv/v=-dt/t). These changes correlated well with initiation and propagation of fracture at the face of this normal slope. It is concluded that cost effective technique, PANI has a good potential for the monitoring of time lapse changes of evolving fractures.

  17. Could monopronucleated ICSI zygotes be considered for transfer? Analysis through time-lapse monitoring and PGS.

    Science.gov (United States)

    Mateo, S; Vidal, F; Parriego, M; Rodríguez, I; Montalvo, V; Veiga, A; Boada, M

    2017-07-01

    The purpose of this study was to investigate the chromosomal constitution and the developmental potential of intracytoplasmic sperm injection (ICSI) deriving embryos displaying a single pronucleus at the zygote stage. Eighty-eight embryos from single pronucleus (1PN) two polar bodies (2PB) ICSI zygotes from 64 preimplantational genetic screening (PGS) cycles (October 2012-December 2014), were retrospectively analyzed. Zygotes were cultured in a time-lapse incubator. Embryo biopsy was performed on day 3 and genetic analysis approached by array comparative genomic hybridization. Chromosomal analysis revealed that 17% (15/88) of embryos derived from 1PN 2PB zygotes were diagnosed as euploid. After blastomere biopsy at day 3, the blastocyst rate at day 5 was 3.4% (3/88). Only 2.3% (2/88) euploid blastocysts were obtained. In two couples and after counseling and patient agreement, the transfer of a euploid blastocyst from a 1PN 2PB ICSI zygote was performed resulting in the birth of a healthy child. These results open the possibility to consider embryos coming from 1PN 2PB ICSI zygotes for transfer when no other embryos from 2PN 2PB ICSI zygotes are available and if a PGS diagnosis of euploidy is obtained. Confirmation of biparental inheritance is strongly recommended.

  18. Time-lapse imaging of neuroblastoma cells to determine cell fate upon gene knockdown.

    Directory of Open Access Journals (Sweden)

    Richa Batra

    Full Text Available Neuroblastoma is the most common extra-cranial solid tumor of early childhood. Standard therapies are not effective in case of poor prognosis and chemotherapy resistance. To improve drug therapy, it is imperative to discover new targets that play a substantial role in tumorigenesis of neuroblastoma. The mitotic machinery is an attractive target for therapeutic interventions and inhibitors can be developed to target mitotic entry, spindle apparatus, spindle activation checkpoint, and mitotic exit. We present an elaborate analysis pipeline to determine cancer specific therapeutic targets by first performing a focused gene expression analysis to select genes followed by a gene knockdown screening assay of live cells. We interrogated gene expression studies of neuroblastoma tumors and selected 240 genes relevant for tumorigenesis and cell cycle. With these genes we performed time-lapse screening of gene knockdowns in neuroblastoma cells. We classified cellular phenotypes and used the temporal context of the perturbation effect to determine the sequence of events, particularly the mitotic entry preceding cell death. Based upon this phenotype kinetics from the gene knockdown screening, we inferred dynamic gene functions in mitosis and cell proliferation. We identified six genes (DLGAP5, DSCC1, SMO, SNRPD1, SSBP1, and UBE2C with a vital role in mitosis and these are promising therapeutic targets for neuroblastoma. Images and movies of every time point of all screened genes are available at https://ichip.bioquant.uni-heidelberg.de.

  19. Monitoring of In-Situ Remediation By Time Lapse 3D Geo-Electric Measurements

    Science.gov (United States)

    Kanli, A. I.; Tildy, P.; Neducza, B.; Nagy, P.; Hegymegi, C.

    2017-12-01

    Injection of chemical oxidant solution to degrade the subsurface contaminants can be used for hydrocarbon contamination remediation. In this study, we developed a non-destructive measurement strategy to monitor oxidative in-situ remediation processes. The difficulties of the presented study originate from the small volume of conductive solution that can be used due to environmental considerations. Due to the effect of conductive groundwater and the high clay content of the targeted layer and the small volume of conductive solution that can be used due to environmental considerations, a site specific synthetic modelling is necessary for measurement design involving the results of preliminary 2D ERT measurements, electrical conductivity measurements of different active agents and expected resistivity changes calculated by soil resistivity modelling. Because of chemical biodegradation, the results of soil resistivity modelling have suggested that the reagent have complex effects on contaminated soils. As a result the plume of resistivity changes caused by the injected agent was determined showing strong fracturing effect because of the high pressure of injection. 3D time-lapse geo-electric measurements were proven to provide a usable monitoring tool for in-situ remediation as a result of our sophisticated tests and synthetic modelling.

  20. Estimation of soil hydraulic properties based on time-lapse Ground-Penetrating Radar (GPR) measurements

    Science.gov (United States)

    Jaumann, Stefan; Klenk, Patrick; Roth, Kurt

    2015-04-01

    Recent developments brought surface-based GPR measurements to a precision that make them useful for estimating soil hydraulic properties. For this study, we estimate Mualem-Brooks-Corey parameters for a layered subsurface material distribution employing the Levenberg-Marquardt inversion algorithm. The required measurement data were recorded at our artificial test site ASSESS, where we forced the hydraulic system with a fluctuating water table and observed the dynamic deformation of the capillary fringe with time-lapse GPR. Subsequently, these measurements were simulated based on a model comprising (i) the Richards equation describing the temporal evolution of the soil hydraulic system which was solved with MUPHI, (ii) the Complex Refractive Index Model (CRIM) serving as petrophysical relationship which links the soil hydraulic model to (iii) the electrodynamic model consisting of Maxwell's equations which are solved with MEEP. For the objective function of the optimization algorithm, both measured and simulated GPR data were evaluated with a semi-automated wavelet feature detection algorithm allowing to directly compare the travel time and amplitude of the GPR signal. In this presentation, we discuss the results of the inversion based on the inversion of GPR data and we also discuss how including Time Domain Reflectometry (TDR) measurement data influences the estimated parameters.

  1. Direct prediction of spatially and temporally varying physical properties from time-lapse electrical resistance data

    Science.gov (United States)

    Hermans, Thomas; Oware, Erasmus; Caers, Jef

    2016-09-01

    Time-lapse applications of electrical methods have grown significantly over the last decade. However, the quantitative interpretation of tomograms in terms of physical properties, such as salinity, temperature or saturation, remains difficult. In many applications, geophysical models are transformed into hydrological models, but this transformation suffers from spatially and temporally varying resolution resulting from the regularization used by the deterministic inversion. In this study, we investigate a prediction-focused approach (PFA) to directly estimate subsurface physical properties with electrical resistance data, circumventing the need for classic tomographic inversions. First, we generate a prior set of resistance data and physical property forecast through hydrogeological and geophysical simulations mimicking the field experiment. We reduce the dimension of both the data and the forecast through principal component analysis in order to keep the most informative part of both sets in a reduced dimension space. Then, we apply canonical correlation analysis to explore the relationship between the data and the forecast in their reduced dimension space. If a linear relationship can be established, the posterior distribution of the forecast can be directly sampled using a Gaussian process regression where the field data scores are the conditioning data. In this paper, we demonstrate PFA for various physical property distributions. We also develop a framework to propagate the estimated noise level in the reduced dimension space. We validate the results by a Monte Carlo study on the posterior distribution and demonstrate that PFA yields accurate uncertainty for the cases studied.

  2. Observation of human embryonic behavior in vitro by high-resolution time-lapse cinematography.

    Science.gov (United States)

    Iwata, Kyoko; Mio, Yasuyuki

    2016-07-01

    Assisted reproductive technology (ART) has yielded vast amounts of information and knowledge on human embryonic development in vitro; however, still images provide limited data on dynamic changes in the developing embryos. Using our high-resolution time-lapse cinematography (hR-TLC) system, we were able to describe normal human embryonic development continuously from the fertilization process to the hatched blastocyst stage in detail. Our hR-TLC observation also showed the embryonic abnormality of a third polar body (PB)-like substance likely containing a small pronucleus being extruded and resulting in single-pronucleus (1PN) formation, while our molecular biological investigations suggested the possibility that some 1PN embryos could be diploid, carrying both maternal and paternal genomes. Furthermore, in some embryos the extruded third PB-like substance was eventually re-absorbed into the ooplasm resulting in the formation of an uneven-sized, two-PN zygote. In addition, other hR-TLC observations showed that cytokinetic failure was correlated with equal-sized, multi-nucleated blastomeres that were also observed in the embryo showing early initiation of compaction. Assessment combining our hR-TLC with molecular biological techniques enables a better understanding of embryonic development and potential improvements in ART outcomes.

  3. Aberrant behavior of mouse embryo development after blastomere biopsy as observed through time-lapse cinematography.

    Science.gov (United States)

    Ugajin, Tomohisa; Terada, Yukihiro; Hasegawa, Hisataka; Velayo, Clarissa L; Nabeshima, Hiroshi; Yaegashi, Nobuo

    2010-05-15

    To analyze whether blastomere biopsy affects early embryonal growth as observed through time-lapse cinematography. Comparative prospective study between embryos in which a blastomere was removed and embryos in which a blastomere was not removed. An experimental laboratory of the university. We calculated the time between blastocele formation and the end of hatching, the time between the start and end of hatching, the number of contractions and expansions between blastocyst formation and the end of hatching, and the maximum diameter of the expanded blastocyst. In blastomere removal embryos, compaction began at the six-cell stage instead of at the eight-cell stage. We also found that hatching was delayed in these embryos as compared with matched controls. Moreover, the frequency of contraction and expansion movements after blastocyst formation was significantly higher in the blastomere removal group as compared with the control group. Finally, the maximum diameter of the expanded blastocyst just before hatching was not significantly different between both groups. These findings suggested that blastomere removal has an adverse effect on embryonic development around the time of hatching. Thus, future developments in preimplantation genetic diagnosis and screening should involve further consideration and caution in light of the influence of blastomere biopsy on embryonal growth. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  4. Mathematical analysis of endothelial sibling pair cell-cell interactions using time-lapse cinematography data.

    Science.gov (United States)

    Brown, L M; Ryan, U S; Absher, M; Olazabal, B M

    1982-01-01

    The sibling pairs from two different endothelial cell cultures were analysed by time-lapse cinematography. It was shown that wounded and regular (low density seeded) cultures differed in the behaviour patterns of their siblings. The cultures differed most significantly in the minimum interdivision time (IDT) which was 27% lower for the wounded culture. In the wounded culture there was a greater correlation of IDT values between sibling pairs. IDT values recorded both for paired and for unpaired cells were shorter for the wounded than for the regular culture. The mean IDT for unpaired cells was longer than the mean IDT for paired cells in the regular culture. Thus paired cells in the regular culture, had shorter IDTs, but not as short as in the wounded culture. It was significant that in the wounded culture the first generation of siblings were very close (less than 150 microns apart) at division. Overall the behaviour differences between the two cultures resulted in a higher rate of increase in cell numbers, and thus faster repair, of the wounded monolayer.

  5. Time-lapse analysis of potential cellular responsiveness to Johrei, a Japanese healing technique.

    Science.gov (United States)

    Taft, Ryan; Moore, Dan; Yount, Garret

    2005-01-24

    Johrei is an alternative healing practice which involves the channeling of a purported universal healing energy to influence the health of another person. Despite little evidence to support the efficacy of such practices the use of such treatments is on the rise. We assessed cultured human cancer cells for potential responsiveness to Johrei treatment from a short distance. Johrei treatment was delivered by practitioners who participated in teams of two, alternating every half hour for a total of four hours of treatment. The practitioners followed a defined set of mental procedures to minimize variability in mental states between experiments. An environmental chamber maintained optimal growth conditions for cells throughout the experiments. Computerized time-lapse microscopy allowed documentation of cancer cell proliferation and cell death before, during and after Johrei treatments. Comparing eight control experiments with eight Johrei intervention experiments, we found no evidence of a reproducible cellular response to Johrei treatment. Cell death and proliferation rates of cultured human cancer cells do not appear responsive to Johrei treatment from a short distance.

  6. Time-lapse imaging of human heart motion with switched array UWB radar.

    Science.gov (United States)

    Brovoll, Sverre; Berger, Tor; Paichard, Yoann; Aardal, Øyvind; Lande, Tor Sverre; Hamran, Svein-Erik

    2014-10-01

    Radar systems for detection of human heartbeats have mostly been single-channel systems with limited spatial resolution. In this paper, a radar system for ultra-wideband (UWB) imaging of the human heart is presented. To make the radar waves penetrate the human tissue the antenna is placed very close to the body. The antenna is an array with eight elements, and an antenna switch system connects the radar to the individual elements in sequence to form an image. Successive images are used to build up time-lapse movies of the beating heart. Measurements on a human test subject are presented and the heart motion is estimated at different locations inside the body. The movies show rhythmic motion consistent with the beating heart, and the location and shape of the reflections correspond well with the expected response form the heart wall. The spatial dependent heart motion is compared to ECG recordings, and it is confirmed that heartbeat modulations are seen in the radar data. This work shows that radar imaging of the human heart may provide valuable information on the mechanical movement of the heart.

  7. Segmentation Method of Time-Lapse Microscopy Images with the Focus on Biocompatibility Assessment.

    Science.gov (United States)

    Soukup, Jindřich; Císař, Petr; Šroubek, Filip

    2016-06-01

    Biocompatibility testing of new materials is often performed in vitro by measuring the growth rate of mammalian cancer cells in time-lapse images acquired by phase contrast microscopes. The growth rate is measured by tracking cell coverage, which requires an accurate automatic segmentation method. However, cancer cells have irregular shapes that change over time, the mottled background pattern is partially visible through the cells and the images contain artifacts such as halos. We developed a novel algorithm for cell segmentation that copes with the mentioned challenges. It is based on temporal differences of consecutive images and a combination of thresholding, blurring, and morphological operations. We tested the algorithm on images of four cell types acquired by two different microscopes, evaluated the precision of segmentation against manual segmentation performed by a human operator, and finally provided comparison with other freely available methods. We propose a new, fully automated method for measuring the cell growth rate based on fitting a coverage curve with the Verhulst population model. The algorithm is fast and shows accuracy comparable with manual segmentation. Most notably it can correctly separate live from dead cells.

  8. Environmental Monitoring Of Leaks Using Time Lapsed Long Electrode Electrical Resistivity

    International Nuclear Information System (INIS)

    Rucker, D.F.; Fink, J.B.; Loke, M.H.; Myers, D.A.

    2009-01-01

    Highly industrialized areas pose significant challenges for surface based electrical resistivity characterization and monitoring due to the high degree of metallic infrastructure. The infrastructure is typically several orders of magnitude more conductive than the desired targets, preventing the geophysicist from obtaining a clear picture of the subsurface. These challenges may be minimized if steel-cased wells are used as long electrodes. We demonstrate a method of using long electrodes in a complex nuclear waste facility to monitor a simulated leak from an underground storage tank. The leak was simulated by injecting high conductivity fluid in a perforated well and the resistivity measurements were made before and after the leak test. The data were processed in four dimensions, where a regularization procedure was applied in both the time and space domains. The results showed a lowered resistivity feature develop south of the injection site. The time lapsed regularization parameter had a strong influence on the differences in inverted resistivity between the pre and post datasets, potentially making calibration of the results to specific hydrogeologic parameters difficult.

  9. Time-lapse analysis of potential cellular responsiveness to Johrei, a Japanese healing technique

    Directory of Open Access Journals (Sweden)

    Moore Dan

    2005-01-01

    Full Text Available Abstract Background Johrei is an alternative healing practice which involves the channeling of a purported universal healing energy to influence the health of another person. Despite little evidence to support the efficacy of such practices the use of such treatments is on the rise. Methods We assessed cultured human cancer cells for potential responsiveness to Johrei treatment from a short distance. Johrei treatment was delivered by practitioners who participated in teams of two, alternating every half hour for a total of four hours of treatment. The practitioners followed a defined set of mental procedures to minimize variability in mental states between experiments. An environmental chamber maintained optimal growth conditions for cells throughout the experiments. Computerized time-lapse microscopy allowed documentation of cancer cell proliferation and cell death before, during and after Johrei treatments. Results Comparing eight control experiments with eight Johrei intervention experiments, we found no evidence of a reproducible cellular response to Johrei treatment. Conclusion Cell death and proliferation rates of cultured human cancer cells do not appear responsive to Johrei treatment from a short distance.

  10. Monitoring water flows with time-lapse Electrical Resistivity Tomography on the Super-Sauze landslide

    Science.gov (United States)

    Gance, J.; Sailhac, P.; Malet, J.-P.; Grandjean, G.; Supper, R.; Jochum, B.; Ottowitz, D.

    2012-04-01

    This work presents results of a permanent hydro-geophysical monitoring of an active landslide developed in clay-shales. Hydrology has been proved to be a major factor controlling the Super-Sauze earthflow behavior, but it knowledge still limited mainly because of the importance of spatial heterogeneities. The geometry of the bedrock creates internal crests and gullies that can guide waterflows or create a lock and engender an excess of pore water pressure; the soil surface characteristics plays also a large role in the surface hydraulic conductivity, and therefore, on the infiltration pattern. To understand in detail these processes, it is therefore important to monitor spatially at large scale (with high resolution) those phenomena and to overcome the monitoring difficulties inherent to a fast-moving clayey earthflow. The objectives of the survey are to identify and characterize spatially and temporarily the water flow circulation within the landslide body over a period of one year. The studied profile measures 114 m long and is surveyed with 93 electrodes spaced from 0.5, 1 or 2 meter according the soil surface cracking. Four resistivity datasets of 4300 measurements are acquired each day using a gradient array since May 2011. The monitoring is performed with the GEOMON4D system, developed by the Geological Survey of Austria. To facilitate the interpretation, humidity, conductivity, temperature, and piezometer sensors are placed along the profile. Two dGPS antenna placed upstream and downstream the profile allow to correlate the results with soil displacement. Lefranc tests and granulometry results realized on several samples have shown the important heterogeneities of the near surface. The objective of this work is to present the data processing strategy for the analysis of long periods time-lapse ERT survey of natural rain events taking into account changes through time of the position of the electrodes, changes in the soil surface state and important changes

  11. Time-Lapse Dynamics of the Mouse Oocyte Chromatin Organisation during Meiotic Resumption

    Directory of Open Access Journals (Sweden)

    Martina Belli

    2014-01-01

    Full Text Available In the mammalian oocyte, distinct patterns of centromeres and pericentromeric heterochromatin localisation correlate with the gamete’s developmental competence. Mouse antral oocytes display two main types of chromatin organisation: SN oocytes, with a ring of Hoechst-positive chromatin surrounding the nucleolus, and NSN oocytes lacking this ring. When matured to MII and fertilised, only SN oocytes develop beyond the 2-cell, and reach full term. To give detailed information on the dynamics of the SN or NSN chromatin during meiosis resumption, we performed a 9 hr time-lapse observation. The main significant differences recorded are: (1 reduction of the nuclear area only in SN oocytes; (2 ~17 min delay of GVBD in NSN oocytes; (3 chromatin condensation, after GVBD, in SN oocytes; (4 formation of 4-5 CHCs in SN oocytes; (5 increase of the perivitelline space, ~57 min later in NSN oocytes; (6 formation of a rosette-like disposition of CHCs, ~84 min later in SN oocytes; (7 appearance of the MI plate ~40 min later in NSN oocytes. Overall, we described a pathway of transition from the GV to the MII stage that is punctuated of discrete recordable events showing their specificity and occurring with different time kinetics in the two types of oocytes.

  12. Untangling cell tracks: Quantifying cell migration by time lapse image data analysis.

    Science.gov (United States)

    Svensson, Carl-Magnus; Medyukhina, Anna; Belyaev, Ivan; Al-Zaben, Naim; Figge, Marc Thilo

    2018-03-01

    Automated microscopy has given researchers access to great amounts of live cell imaging data from in vitro and in vivo experiments. Much focus has been put on extracting cell tracks from such data using a plethora of segmentation and tracking algorithms, but further analysis is normally required to draw biologically relevant conclusions. Such relevant conclusions may be whether the migration is directed or not, whether the population has homogeneous or heterogeneous migration patterns. This review focuses on the analysis of cell migration data that are extracted from time lapse images. We discuss a range of measures and models used to analyze cell tracks independent of the biological system or the way the tracks were obtained. For single-cell migration, we focus on measures and models giving examples of biological systems where they have been applied, for example, migration of bacteria, fibroblasts, and immune cells. For collective migration, we describe the model systems wound healing, neural crest migration, and Drosophila gastrulation and discuss methods for cell migration within these systems. We also discuss the role of the extracellular matrix and subsequent differences between track analysis in vitro and in vivo. Besides methods and measures, we are putting special focus on the need for openly available data and code, as well as a lack of common vocabulary in cell track analysis. © 2017 International Society for Advancement of Cytometry. © 2017 International Society for Advancement of Cytometry.

  13. Time-Lapse Video Microscopy for Assessment of EYFP-Parkin Aggregation as a Marker for Cellular Mitophagy.

    Science.gov (United States)

    Di Sante, Gabriele; Casimiro, Mathew C; Pestell, Timothy G; Pestell, Richard G

    2016-05-04

    Time-lapse video microscopy can be defined as the real time imaging of living cells. This technique relies on the collection of images at different time points. Time intervals can be set through a computer interface that controls the microscope-integrated camera. This kind of microscopy requires both the ability to acquire very rapid events and the signal generated by the observed cellular structure during these events. After the images have been collected, a movie of the entire experiment is assembled to show the dynamic of the molecular events of interest. Time-lapse video microscopy has a broad range of applications in the biomedical research field and is a powerful and unique tool for following the dynamics of the cellular events in real time. Through this technique, we can assess cellular events such as migration, division, signal transduction, growth, and death. Moreover, using fluorescent molecular probes we are able to mark specific molecules, such as DNA, RNA or proteins and follow them through their molecular pathways and functions. Time-lapse video microscopy has multiple advantages, the major one being the ability to collect data at the single-cell level, that make it a unique technology for investigation in the field of cell biology. However, time-lapse video microscopy has limitations that can interfere with the acquisition of high quality images. Images can be compromised by both external factors; temperature fluctuations, vibrations, humidity and internal factors; pH, cell motility. Herein, we describe a protocol for the dynamic acquisition of a specific protein, Parkin, fused with the enhanced yellow fluorescent protein (EYFP) in order to track the selective removal of damaged mitochondria, using a time-lapse video microscopy approach.

  14. BactImAS: a platform for processing and analysis of bacterial time-lapse microscopy movies.

    Science.gov (United States)

    Mekterović, Igor; Mekterović, Darko; Maglica, Zeljka

    2014-07-25

    The software available to date for analyzing image sequences from time-lapse microscopy works only for certain bacteria and under limited conditions. These programs, mostly MATLAB-based, fail for microbes with irregular shape, indistinct cell division sites, or that grow in closely packed microcolonies. Unfortunately, many organisms of interest have these characteristics, and analyzing their image sequences has been limited to time consuming manual processing. Here we describe BactImAS - a modular, multi-platform, open-source, Java-based software delivered both as a standalone program and as a plugin for Icy. The software is designed for extracting and visualizing quantitative data from bacterial time-lapse movies. BactImAS uses a semi-automated approach where the user defines initial cells, identifies cell division events, and, if necessary, manually corrects cell segmentation with the help of user-friendly GUI and incorporated ImageJ application. The program segments and tracks cells using a newly-developed algorithm designed for movies with difficult-to-segment cells that exhibit small frame-to-frame differences. Measurements are extracted from images in a configurable, automated fashion and an SQLite database is used to store, retrieve, and exchange all acquired data. Finally, the BactImAS can generate configurable lineage tree visualizations and export data as CSV files. We tested BactImAS on time-lapse movies of Mycobacterium smegmatis and achieved at least 10-fold reduction of processing time compared to manual analysis. We illustrate the power of the visualization tool by showing heterogeneity of both icl expression and cell growth atop of a lineage tree. The presented software simplifies quantitative analysis of time-lapse movies overall and is currently the only available software for the analysis of mycobacteria-like cells. It will be of interest to the community of both end-users and developers of time-lapse microscopy software.

  15. Using stochastic borehole seismic velocity tomography and Bayesian simulation to estimate Ni, Cu and Co grades.

    Science.gov (United States)

    Perozzi, Lorenzo; Gloaguen, Erwan; Rondenay, Stephane; Leite, André; McDowell, Glenn; Wheeler, Robert

    2010-05-01

    In the mining industry, classic methods to build a grade model for ore deposits are based on kriging or cokriging of grades for targeted minerals measured in drill core in fertile geological units. As the complexity of the geological geometry increases, so does the complexity of grade estimations. For example, in layered mafic or ultramafic intrusions, it is necessary to know the layering geometry in order to perform kriging of grades in the most fertile zones. Without additional information on geological framwork, the definition of fertile zones is a low-precision exercise that requires extensive experience and good ability from the geologist. Recently, thanks to computer and geophysical tool improvements, seismic tomography became very attractive for many application fields. Indeed, this non-intrusive technique allows inferring the mechanical properties of the ground using travel times and amplitude analysis of the transmitted wavelet between two boreholes, hence provide additional information on the nature of the deposit. Commonly used crosshole seismic velocity tomography algorithms estimate 2D slowness models (inverse of velocity) in the plane between the boreholes using the measured direct wave travel times from the transmitter (located in one of the hole) to the receivers (located in the other hole). Furthermore, geophysical borehole logging can be used to constrain seismic tomography between drill holes. Finally, this project aims to estimate grade of economically worth mineral by integrating seismic tomography data with respectively drill core measured grades acquired by Vale Inco for one of their mine sites in operation. In this study, a new type algorithm that combines geostatistical simulation and tomography in the same process (namely stochastic tomography) has been used. The principle of the stochastic tomography is based on the straight ray approximation and use the linear relationship between travel time and slowness to estimate the slowness

  16. Can a grain size-dependent viscosity help yielding realistic seismic velocities of LLSVPs?

    Science.gov (United States)

    Schierjott, J.; Cheng, K. W.; Rozel, A.; Tackley, P. J.

    2017-12-01

    Seismic studies show two antipodal regions of low shear velocity at the core-mantle boundary (CMB), one beneath the Pacific and one beneath Africa. These regions, called Large Low Shear Velocity Provinces (LLSVPs), are thought to be thermally and chemically distinct and thus have a different density and viscosity. Whereas there is some general consensus about the density of the LLSVPs the viscosity is still a very debated topic. So far, in numerical studies the viscosity is treated as either depth- and/or temperature- dependent but the potential grain size- dependence of the viscosity is neglected most of the time. In this study we use a self-consistent convection model which includes a grain size- dependent rheology based on the approach by Rozel et al. (2011) and Rozel (2012). Further, we consider a primordial layer and a time-dependent basalt production at the surface to dynamically form the present-day chemical heterogeneities, similar to earlier studies, e.g by Nakagawa & Tackley (2014). With this model we perform a parameter study which includes different densities and viscosities of the imposed primordial layer. We detect possible thermochemical piles based on different criterions, compute their average effective viscosity, density, rheology and grain size and investigate which detecting criterion yields the most realistic results. Our preliminary results show that a higher density and/or viscosity of the piles is needed to keep them at the core-mantle boundary (CMB). Relatively to the ambient mantle grain size is high in the piles but due to the temperature at the CMB the viscosity is not remarkably different than the one of ordinary plumes. We observe that grain size is lower if the density of the LLSVP is lower than the one of our MORB material. In that case the average temperature of the LLSVP is also reduced. Interestingly, changing the reference viscosity is responsible for a change in the average viscosity of the LLSVP but not for a different average

  17. A method for quantifying cloud immersion in a tropical mountain forest using time-lapse photography

    Science.gov (United States)

    Bassiouni, Maoya; Scholl, Martha A.; Torres-Sanchez, Angel J.; Murphy, Sheila F.

    2017-01-01

    Quantifying the frequency, duration, and elevation range of fog or cloud immersion is essential to estimate cloud water deposition in water budgets and to understand the ecohydrology of cloud forests. The goal of this study was to develop a low-cost and high spatial-coverage method to detect occurrence of cloud immersion within a mountain cloud forest by using time-lapse photography. Trail cameras and temperature/relative humidity sensors were deployed at five sites covering the elevation range from the assumed lifting condensation level to the mountain peaks in the Luquillo Mountains of Puerto Rico. Cloud-sensitive image characteristics (contrast, the coefficient of variation and the entropy of pixel luminance, and image colorfulness) were used with a k-means clustering approach to accurately detect cloud-immersed conditions in a time series of images from March 2014 to May 2016. Images provided hydrologically meaningful cloud-immersion information while temperature-relative humidity data were used to refine the image analysis using dew point information and provided temperature gradients along the elevation transect. Validation of the image processing method with human-judgment based classification generally indicated greater than 90% accuracy. Cloud-immersion frequency averaged 80% at sites above 900 m during nighttime hours and 49% during daytime hours, and was consistent with diurnal patterns of cloud immersion measured in a previous study. Results for the 617 m site demonstrated that cloud immersion in the Luquillo Mountains rarely occurs at the previously-reported cloud base elevation of about 600 m (11% during nighttime hours and 5% during daytime hours). The framework presented in this paper will be used to monitor at a low cost and high spatial resolution the long-term variability of cloud-immersion patterns in the Luquillo Mountains, and can be applied to ecohydrology research at other cloud-forest sites or in coastal ecosystems with advective sea

  18. Using electromagnetic conductivity imaging to generate time-lapse soil moisture estimates.

    Science.gov (United States)

    Huang, Jingyi; Scuderio, Elia; Corwin, Dennis; Triantafilis, John

    2015-04-01

    Irrigated agriculture is crucial to the agricultural productivity of the Moreno valley. To maintain profitability, more will need to be done by irrigators with less water, owing to competing demands from rapidly expanding urbanisation in southern California. In this regard, irrigators need to understand the spatial and temporal variation of soil moisture to discern inefficiencies. However, soil moisture is difficult to measure and monitor, unless a large bank of soil sensors are installed and at various depths in the profile. In order to value add to the limited amount of information, geophysical techniques, such as direct current resisivity (DCR) arrays are used to develop electrical resistivity images (ERI). Whilst successful the approach is time consuming and labour intensive. In this research we describe how equivalent data can be collected using a proximal sensing electromagnetic (EM) induction instrument (i.e. DUALEM-421) and inversion software (EM4Soil) to generate EM conductivity images (EMCI). Figure 1 shows the EMCI generated from DUALEM-421 data acquired at various days of a time-lapse experiment and including; day a) 0, b) 1, c) 2, d) 3, e) 5, f) 7 and g) 11. We calibrate the estimates of true electrical conductivity (sigma - mS/m) with volumetric moisture content and show with good accuracy the spatial and temporal variation of soil moisture status and over 12 day period. The results show clearly that the pivot sprinkler irrigation system is effective at providing sufficient amounts of water to the top 0.5 m of a Lucerne crop (i.e. red shaded areas of high sigma). However, in some places faulty sprinklers are evident owing to the lack of wetting (i.e. blue shaded areas of low sigma). In addition, and over time, our approach shows clearly the effect the Lucerne crop has in drying the soil profile and using the soil moisture.

  19. Tracking snowmelt in the subsurface: time-lapse electrical resistivity imaging on an alpine hill slope.

    Science.gov (United States)

    Thayer, D.; Parsekian, A.; Hyde, K.; Beverly, D.; Speckman, H. N.; Ewers, B. E.

    2015-12-01

    In the mountain West region the winter snowpack provides more than 70% of our annual water supply. Modeling and predicting the timing and magnitude of snowmelt-driven water yield is difficult due to the complexities of hydrologic systems that move meltwater from snow to rivers. Particular challenges are understanding the temporal and spatial domain of subsurface hydraulic processes at relevant scales, which range from points to catchments. Subsurface characterization often requires borehole instrumentation, which is expensive and extremely difficult to install in remote, rugged terrain. Advancements in non-invasive geophysical methods allow us to monitor changes in geophysical parameters over time and infer changes in hydraulic processes. In the No-Name experimental catchment in the Medicine Bow National Forest in Wyoming, we are conducting a multi-season, time-lapse electrical resistivity imaging survey on a sub-alpine hill slope. This south-facing, partially forested slope ranges from 5 degrees to 35 degrees in steepness and consists of a soil mantle covering buried glacial talus deposits of unknown depth. A permanent grid of down-slope and cross-slope electrode arrays is monitored up to four times a day. The arrays span the entire vertical distance of the slope, from an exposed bedrock ridge to a seasonal drainage below, and cover treed and non-treed areas. Geophysical measurements are augmented by temperature and moisture time-series instrumented below the surface in a contiguous 3 meter borehole. A time-series of multiple resistivity models each day from May to July shows the changing distribution of subsurface moisture during a seasonal drying sequence punctuated by isolated rain events. Spatial patterns of changing moisture indicate that soil and gravel in the top two meters drain into a saturated layer parallel to the slope which overlies less saturated material. These results suggest that water from snowmelt and rain events tends to move down-slope beneath

  20. ENVIRONMENTAL MONITORING OF LEAKS USING TIME LAPSED LONG ELECTRODE ELECTRICAL RESISTIVITY

    International Nuclear Information System (INIS)

    Myers, D.A.; Rucker, D.F.; Fink, J.B.; Loke, M.H.

    2009-01-01

    Highly industrialized areas pose challenges for surface electrical resistivity characterization due to metallic infrastructure. The infrastructure is typically more conductive than the desired targets and will mask the deeper subsurface information. These challenges may be minimized if steel-cased wells are used as long electrodes in the area near the target. We demonstrate a method of using long electrodes to electrically monitor a simulated leak from an underground storage tank with both synthetic examples and a field demonstration. The synthetic examples place a simple target of varying electrical properties beneath a very low resistivity layer. The layer is meant to replicate the effects of infrastructure. Both surface and long electrodes are tested on the synthetic domain. The leak demonstration for the field experiment is simulated by injecting a high conductivity fluid in a perforated well within the S tank farm at Hanford, and the resistivity measurements are made before and after the leak test. All data are processed in four dimensions, where a regularization procedure is applied in both the time and space domains. The synthetic test case shows that the long electrode ERM could detect relative changes in resistivity that are commensurate with the differing target properties. The surface electrodes, on the other hand, had a more difficult time matching the original target's footprint. The field results shows a lowered resistivity feature develop south of the injection site after cessation of the injections. The time lapsed regularization parameter has a strong influence on the differences in inverted resistivity between the pre and post injection datasets, but the interpretation of the target is consistent across all values of the parameter. The long electrode ERM method may provide a tool for near real-time monitoring of leaking underground storage tanks.

  1. ENVIRONMENTAL MONITORING OF LEAKS USING TIME LAPSED LONG ELECTRODE ELECTRICAL RESISTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    MYERS DA; RUCKER DF; FINK JB; LOKE MH

    2009-12-16

    Highly industrialized areas pose challenges for surface electrical resistivity characterization due to metallic infrastructure. The infrastructure is typically more conductive than the desired targets and will mask the deeper subsurface information. These challenges may be minimized if steel-cased wells are used as long electrodes in the area near the target. We demonstrate a method of using long electrodes to electrically monitor a simulated leak from an underground storage tank with both synthetic examples and a field demonstration. The synthetic examples place a simple target of varying electrical properties beneath a very low resistivity layer. The layer is meant to replicate the effects of infrastructure. Both surface and long electrodes are tested on the synthetic domain. The leak demonstration for the field experiment is simulated by injecting a high conductivity fluid in a perforated well within the S tank farm at Hanford, and the resistivity measurements are made before and after the leak test. All data are processed in four dimensions, where a regularization procedure is applied in both the time and space domains. The synthetic test case shows that the long electrode ERM could detect relative changes in resistivity that are commensurate with the differing target properties. The surface electrodes, on the other hand, had a more difficult time matching the original target's footprint. The field results shows a lowered resistivity feature develop south of the injection site after cessation of the injections. The time lapsed regularization parameter has a strong influence on the differences in inverted resistivity between the pre and post injection datasets, but the interpretation of the target is consistent across all values of the parameter. The long electrode ERM method may provide a tool for near real-time monitoring of leaking underground storage tanks.

  2. Absolute earthquake locations using 3-D versus 1-D velocity models below a local seismic network: example from the Pyrenees

    Science.gov (United States)

    Theunissen, T.; Chevrot, S.; Sylvander, M.; Monteiller, V.; Calvet, M.; Villaseñor, A.; Benahmed, S.; Pauchet, H.; Grimaud, F.

    2018-03-01

    Local seismic networks are usually designed so that earthquakes are located inside them (primary azimuthal gap 180° and distance to the first station higher than 15 km). Errors on velocity models and accuracy of absolute earthquake locations are assessed based on a reference data set made of active seismic, quarry blasts and passive temporary experiments. Solutions and uncertainties are estimated using the probabilistic approach of the NonLinLoc (NLLoc) software based on Equal Differential Time. Some updates have been added to NLLoc to better focus on the final solution (outlier exclusion, multiscale grid search, S-phases weighting). Errors in the probabilistic approach are defined to take into account errors on velocity models and on arrival times. The seismicity in the final 3-D catalogue is located with a horizontal uncertainty of about 2.0 ± 1.9 km and a vertical uncertainty of about 3.0 ± 2.0 km.

  3. Upper mantle seismic velocity anomaly beneath southern Taiwan as revealed by teleseismic relative arrival times

    Science.gov (United States)

    Chen, Po-Fei; Huang, Bor-Shouh; Chiao, Ling-Yun

    2011-01-01

    Probing the lateral heterogeneity of the upper mantle seismic velocity structure beneath southern and central Taiwan is critical to understanding the local tectonics and orogeny. A linear broadband array that transects southern Taiwan, together with carefully selected teleseismic sources with the right azimuth provides useful constraints. They are capable of differentiating the lateral heterogeneity along the profile with systematic coverage of ray paths. We implement a scheme based on the genetic algorithm to simultaneously determine the relative delayed times of the teleseismic first arrivals of array data. The resulting patterns of the delayed times systematically vary as a function of the incident angle. Ray tracing attributes the observed variations to a high velocity anomaly dipping east in the mantle beneath the southeast of Taiwan. Combining the ray tracing analysis and a pseudo-spectral method to solve the 2-D wave propagations, we determine the extent of the anomaly that best fits the observations via the forward grid search. The east-dipping fast anomaly in the upper mantle beneath the southeast of Taiwan agrees with the results from several previous studies and indicates that the nature of the local ongoing arc-continent collision is likely characterized by the thin-skinned style.

  4. Estimating regional pore pressure distribution using 3D seismic velocities in the Dutch Central North Sea Graben

    NARCIS (Netherlands)

    Winthaegen, P.L.A.; Verweij, J.M.

    2003-01-01

    The application of the empirical Eaton method to calibrated sonic well information and 3D seismic interval velocity data in the southeastern part of the Central North Sea Graben, using the Japsen (Glob. Planet. Change 24 (2000) 189) normal velocitydepth trend, resulted in the identification of an

  5. On the possibility of time-lapse ultrahigh-resolution optical coherence tomography for bladder cancer grading

    Science.gov (United States)

    Yuan, Zhijia; Chen, Bai; Ren, Hugang; Pan, Yingtian

    2009-09-01

    It has been recently demonstrated that the cellular details of bladder epithelium embedded in speckle noise can be uncovered with time-lapse ultrahigh-resolution optical coherence tomography (TL-uOCT) by proper time-lapse frame averaging that takes advantage of cellular micromotion in fresh biological tissue ex vivo. Here, spectral-domain 3-D TL-uOCT is reported to further improve the image fidelity, and new experimental evidence is presented to differentiate normal and cancerous nuclei of rodent bladder epithelia. Results of animal cancer study reveal that despite a slight overestimation (e.g., cancerous (e.g., high-grade DN''~13 μm) urothelia, which may potentially be very useful for enhancing the diagnosis of nonpapillary bladder cancer. More animal study is being conducted to examine the utility to differentiate hyperplasia, dysplasia, and carcinoma in situ.

  6. Hypocenter relocation along the Sunda arc in Indonesia, using a 3D seismic velocity model

    Science.gov (United States)

    Nugraha, Andri Dian; Shiddiqi, Hasbi A.; Widiyantoro, Sri; Thurber, Clifford H.; Pesicek, Jeremy D.; Zhang, Haijiang; Wiyono, Samsul H.; Ramadhan, Mohamad; Wandano,; Irsyam, Mahsyur

    2018-01-01

    The tectonics of the Sunda arc region is characterized by the junction of the Eurasian and Indo‐Australian tectonic plates, causing complex dynamics to take place. High‐seismicity rates in the Indonesian region occur due to the interaction between these tectonic plates. The availability of a denser network of seismometers after the earthquakes of Mw">Mw 9.1 in 2004 and  Mw">Mw 8.6 in 2005 supports various seismic studies, one of which regards the precise relocation of the hypocenters. In this study, hypocenter relocation was performed using a teleseismic double‐difference (DD) relocation method (teletomoDD) combining arrival times of P and S waves from stations at local, regional, and teleseismic distances. The catalog data were taken from the Agency of Meteorology, Climatology, and Geophysics (BMKG) of Indonesia, and the International Seismological Centre (ISC) for the time period of April 2009 to May 2015. The 3D seismic‐wave velocity model with a grid size 1°×1°">1°×1° was used in the travel‐time calculations. Relocation results show a reduction in travel‐time residuals compared with the initial locations. The relocation results better illuminate subducted slabs and active faults in the region such as the Mentawai back thrust and the outer rise in the subduction zone south of Java. Focal mechanisms from the Global Centroid Moment Tensor catalog are analyzed in conjunction with the relocation results, and our synthesis of the results provides further insight into seismogenesis in the region.

  7. The preliminary results: Internal seismic velocity structure imaging beneath Mount Lokon

    Energy Technology Data Exchange (ETDEWEB)

    Firmansyah, Rizky, E-mail: rizkyfirmansyah@hotmail.com [Geophysical Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung, 40132 (Indonesia); Nugraha, Andri Dian, E-mail: nugraha@gf.itb.ac.id [Global Geophysical Group, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung, 40132 (Indonesia); Kristianto, E-mail: kris@vsi.esdm.go.id [Center for Volcanology and Geological Hazard Mitigation (CVGHM), Geological Agency, Bandung, 40122 (Indonesia)

    2015-04-24

    Historical records that before the 17{sup th} century, Mount Lokon had been dormant for approximately 400 years. In the years between 1350 and 1400, eruption ever recorded in Empung, came from Mount Lokon’s central crater. Subsequently, in 1750 to 1800, Mount Lokon continued to erupt again and caused soil damage and fall victim. After 1949, Mount Lokon dramatically increased in its frequency: the eruption interval varies between 1 – 5 years, with an average interval of 3 years and a rest interval ranged from 8 – 64 years. Then, on June 26{sup th}, 2011, standby alert set by the Center for Volcanology and Geological Hazard Mitigation. Peak activity happened on July 4{sup th}, 2011 that Mount Lokon erupted continuously until August 28{sup th}, 2011. In this study, we carefully analyzed micro-earthquakes waveform and determined hypocenter location of those events. We then conducted travel time seismic tomographic inversion using SIMULPS12 method to detemine Vp, Vs and Vp/Vs ratio structures beneath Lokon volcano in order to enhance our subsurface geological structure. During the tomographic inversion, we started from 1-D seismic velocities model obtained from VELEST33 method. Our preliminary results show low Vp, low Vs, and high Vp/Vs are observed beneath Mount Lokon-Empung which are may be associated with weak zone or hot material zones. However, in this study we used few station for recording of micro-earthquake events. So, we suggest in the future tomography study, the adding of some seismometers in order to improve ray coverage in the region is profoundly justified.

  8. How to connect time-lapse recorded trajectories of motile microorganisms with dynamical models in continuous time

    DEFF Research Database (Denmark)

    Pedersen, Jonas Nyvold; Li, Liang; Gradinaru, Cristian

    2016-01-01

    We provide a tool for data-driven modeling of motility, data being time-lapse recorded trajectories. Several mathematical properties of a model to be found can be gleaned from appropriate model-independent experimental statistics, if one understands how such statistics are distorted by the finite...... of these effects that are valid for any reasonable model for persistent random motion. Our findings are illustrated with experimental data and Monte Carlo simulations....

  9. Time-lapse three-dimensional inversion of complex conductivity data using an active time constrained (ATC) approach

    Science.gov (United States)

    Karaoulis, M.; Revil, A.; Werkema, D.D.; Minsley, B.J.; Woodruff, W.F.; Kemna, A.

    2011-01-01

    Induced polarization (more precisely the magnitude and phase of impedance of the subsurface) is measured using a network of electrodes located at the ground surface or in boreholes. This method yields important information related to the distribution of permeability and contaminants in the shallow subsurface. We propose a new time-lapse 3-D modelling and inversion algorithm to image the evolution of complex conductivity over time. We discretize the subsurface using hexahedron cells. Each cell is assigned a complex resistivity or conductivity value. Using the finite-element approach, we model the in-phase and out-of-phase (quadrature) electrical potentials on the 3-D grid, which are then transformed into apparent complex resistivity. Inhomogeneous Dirichlet boundary conditions are used at the boundary of the domain. The calculation of the Jacobian matrix is based on the principles of reciprocity. The goal of time-lapse inversion is to determine the change in the complex resistivity of each cell of the spatial grid as a function of time. Each model along the time axis is called a 'reference space model'. This approach can be simplified into an inverse problem looking for the optimum of several reference space models using the approximation that the material properties vary linearly in time between two subsequent reference models. Regularizations in both space domain and time domain reduce inversion artefacts and improve the stability of the inversion problem. In addition, the use of the time-lapse equations allows the simultaneous inversion of data obtained at different times in just one inversion step (4-D inversion). The advantages of this new inversion algorithm are demonstrated on synthetic time-lapse data resulting from the simulation of a salt tracer test in a heterogeneous random material described by an anisotropic semi-variogram. ?? 2011 The Authors Geophysical Journal International ?? 2011 RAS.

  10. Combined time-lapse magnetic resonance imaging and modeling to investigate colloid deposition and transport in porous media

    OpenAIRE

    LEHOUX, Alizée; FAURE, Paméla; LAFOLIE, Francois; RODTS, Stéphane; COURTIER-MURIAS, Denis; COUSSOT, Philippe; MICHEL, Eric

    2017-01-01

    Colloidal particles can act as vectors of adsorbed pollutants in the subsurface, or be themselves pollutants. They can reach the aquifer and impair groundwater quality. The mechanisms of colloid transport and deposition are often studied in columns filled with saturated porous media. Time-lapse profiles of colloid concentration inside the columns have occasionally been derived from magnetic resonance imaging (MRI) data recorded in transport experiments. These profiles are valuable, in additio...

  11. Time-lapse Imaging of Primary Preneoplastic Mammary Epithelial Cells Derived from Genetically Engineered Mouse Models of Breast Cancer

    OpenAIRE

    Nakles, Rebecca E.; Millman, Sarah L.; Cabrera, M. Carla; Johnson, Peter; Mueller, Susette; Hoppe, Philipp S.; Schroeder, Timm; Furth, Priscilla A.

    2013-01-01

    Time-lapse imaging can be used to compare behavior of cultured primary preneoplastic mammary epithelial cells derived from different genetically engineered mouse models of breast cancer. For example, time between cell divisions (cell lifetimes), apoptotic cell numbers, evolution of morphological changes, and mechanism of colony formation can be quantified and compared in cells carrying specific genetic lesions. Primary mammary epithelial cell cultures are generated from mammary glands without...

  12. Prediction of in-vitro developmental competence of early cleavage-stage mouse embryos with compact time-lapse equipment.

    Science.gov (United States)

    Pribenszky, Csaba; Losonczi, Eszter; Molnár, Miklós; Lang, Zsolt; Mátyás, Szabolcs; Rajczy, Klára; Molnár, Katalin; Kovács, Péter; Nagy, Péter; Conceicao, Jason; Vajta, Gábor

    2010-03-01

    Single blastocyst transfer is regarded as an efficient way to achieve high pregnancy rates and to avoid multiple pregnancies. Risk of cancellation of transfer due to a lack of available embryos may be reduced by early prediction of blastocyst development. Time-lapse investigation of mouse embryos shows that the time of the first and second cleavage (to the 2- and 3-cell stages, respectively) has a strong predictive value for further development in vitro, while cleavage from the 3-cell to the 4-cell stage has no predictive value. In humans, embryo fragmentation during preimplantation development has been associated with lower pregnancy rates and a higher incidence of developmental abnormalities. Analysis of time-lapse records shows that most fragmentation is reversible in the mouse and is resorbed in an average of 9 h. Daily or bi-daily microscopic checks of embryo development, applied routinely in human IVF laboratories, would fail to detect 36 or 72% of these fragmentations, respectively. Fragmentation occurring in a defined time frame has a strong predictive value for in-vitro embryo development. The practical compact system used in the present trial, based on the 'one camera per patient' principle, has eliminated the usual disadvantages of time-lapse investigations and is applicable for the routine follow-up of in-vitro embryo development. Copyright 2009 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  13. Time-lapse camera trapping as an alternative to pitfall trapping for estimating activity of leaf litter arthropods.

    Science.gov (United States)

    Collett, Rachael A; Fisher, Diana O

    2017-09-01

    Pitfall trapping is the standard technique to estimate activity and relative abundance of leaf litter arthropods. Pitfall trapping is not ideal for long-term sampling because it is lethal, labor-intensive, and may have taxonomic sampling biases. We test an alternative sampling method that can be left in place for several months at a time: verticallyplaced time-lapse camera traps that have a short focal distance, enabling identification of small arthropods. We tested the effectiveness of these time-lapse cameras, and quantified escape and avoidance behavior of arthropod orders encountering pitfall traps by placing cameras programed with a range of sampling intervals above pitfalls, to assess numerical, taxonomic, and body size differences in samples collected by the two methods. Cameras programed with 1- or 15-min intervals recorded around twice as many arthropod taxa per day and a third more individuals per day than pitfall traps. Hymenoptera (ants), Embioptera (webspinners), and Blattodea (cockroaches) frequently escaped from pitfalls so were particularly under-sampled by them. The time-lapse camera method effectively samples litter arthropods to collect long-term data. It is standardized, non-lethal, and does not alter the substrate or require frequent visits.

  14. Time-lapse electromagnetic induction surveys under olive tree canopies reveal soil moisture dynamics and controls

    Science.gov (United States)

    Martínez, Gonzalo; Giraldez Cervera, Juan Vicente; Vanderlinden, Karl

    2015-04-01

    Soil moisture (θ) is a critical variable that exerts an important control on plant status and development. Soil sampling, neutron attenuation and electromagnetic methods such as TDR or FDR have been used widely to measure θ and provide point data at a possible range of temporal resolutions. However, these methods require either destructive sampling or permanently installed devices with often limiting measurement depths, or are extremely time-consuming. Moreover, the small support of such measurements compromises its value in heterogeneous soils. To overcome such limitations electromagnetic induction (EMI) can be tested to monitor θ at different spatial and temporal scales. This work investigates the potential of EMI to characterize the spatio-temporal variability of soil moisture from apparent electrical conductivity (ECa) under the canopy of individual olive trees. During one year we measured θ with a frequency of 5 min and ECa on an approximately weekly basis along transects from the tree trunk towards the inter-row area. CS-616 soil moisture sensors where horizontally installed in the walls of a trench at depths of 0.1, 0.2, 0.4, 0.6 and 0.8 m at five locations along the transect, with a separation of 0.8 m. The Dualem-21S sensor was used to measure weekly the ECa at 0.2 m increments, from the tree trunk to a distance of 4.4 m. The results showed similar drying and wetting patterns for θ and ECa. Both variables showed a decreasing pattern from the tree trunk towards the drip line, followed by a sharp increment and constant values towards the center of the inter-row space. This pattern reflects clearly the influence of root-zone water uptake under the tree canopy and higher θ values in the inter-row area where root-water uptake is smaller. Time-lapse ECa data responded to evaporation and infiltration fluxes with the highest sensitivity for the 1 and 1.5 m ECa signals, as compared to the 0.5 and 3.0 m signals. Overall these preliminary results revealed the

  15. Penicillin induced persistence in Chlamydia trachomatis: high quality time lapse video analysis of the developmental cycle.

    Directory of Open Access Journals (Sweden)

    Rachel J Skilton

    2009-11-01

    Full Text Available Chlamydia trachomatis is a major human pathogen with a unique obligate intracellular developmental cycle that takes place inside a modified cytoplasmic structure known as an inclusion. Following entry into a cell, the infectious elementary body (EB differentiates into a non-infectious replicative form known as a reticulate body (RB. RBs divide by binary fission and at the end of the cycle they redifferentiate into EBs. Treatment of C.trachomatis with penicillin prevents maturation of RBs which survive and enlarge to become aberrant RBs within the inclusion in a non-infective persistent state. Persistently infected individuals may be a reservoir for chlamydial infection. The C.trachomatis genome encodes the enzymes for peptidoglycan (PG biosynthesis but a PG sacculus has never been detected. This coupled to the action of penicillin is known as the chlamydial anomaly. We have applied video microscopy and quantitative DNA assays to the chlamydial developmental cycle to assess the effects of penicillin treatment and establish a framework for investigating penicillin induced chlamydial persistence.Addition of penicillin at the time of cell infection does not prevent uptake and the establishment of an inclusion. EB to RB transition occurs but bacterial cytokinesis is arrested by the second binary fission. RBs continue to enlarge but not divide in the presence of penicillin. The normal developmental cycle can be recovered by the removal of penicillin although the large, aberrant RBs do not revert to the normal smaller size but remain present to the completion of the developmental cycle. Chromosomal and plasmid DNA replication is unaffected by the addition of penicillin but the arrest of bacterial cytokinesis under these conditions results in RBs accumulating multiple copies of the genome.We have applied video time lapse microscopy to the study of the chlamydial developmental cycle. Linked with accurate measures of genome replication this provides a

  16. A Novel Methodology for Characterizing Cell Subpopulations in Automated Time-lapse Microscopy

    Directory of Open Access Journals (Sweden)

    Georges Hattab

    2018-02-01

    Full Text Available Time-lapse imaging of cell colonies in microfluidic chambers provides time series of bioimages, i.e., biomovies. They show the behavior of cells over time under controlled conditions. One of the main remaining bottlenecks in this area of research is the analysis of experimental data and the extraction of cell growth characteristics, such as lineage information. The extraction of the cell line by human observers is time-consuming and error-prone. Previously proposed methods often fail because of their reliance on the accurate detection of a single cell, which is not possible for high density, high diversity of cell shapes and numbers, and high-resolution images with high noise. Our task is to characterize subpopulations in biomovies. In order to shift the analysis of the data from individual cell level to cellular groups with similar fluorescence or even subpopulations, we propose to represent the cells by two new abstractions: the particle and the patch. We use a three-step framework: preprocessing, particle tracking, and construction of the patch lineage. First, preprocessing improves the signal-to-noise ratio and spatially aligns the biomovie frames. Second, cell sampling is performed by assuming particles, which represent a part of a cell, cell or group of contiguous cells in space. Particle analysis includes the following: particle tracking, trajectory linking, filtering, and color information, respectively. Particle tracking consists of following the spatiotemporal position of a particle and gives rise to coherent particle trajectories over time. Typical tracking problems may occur (e.g., appearance or disappearance of cells, spurious artifacts. They are effectively processed using trajectory linking and filtering. Third, the construction of the patch lineage consists in joining particle trajectories that share common attributes (i.e., proximity and fluorescence intensity and feature common ancestry. This step is based on patch finding

  17. Spatio-temporal changes in seismic velocity associated with the 2000 activity of Miyakejima volcano as inferred from cross-correlation analyses of ambient noise

    Science.gov (United States)

    Anggono, Titi; Nishimura, Takeshi; Sato, Haruo; Ueda, Hideki; Ukawa, Motoo

    2012-12-01

    Miyakejima volcano, Japan, showed strong and interesting volcanic activities in 2000 with the occurrence of dike intrusions, caldera formation and a large amount of gas emission. To understand temporal changes of the volcanic structure associated with this activity, we apply ambient noise correlation analyses to the seismic records of five seismic stations at Miyakejima volcano from July 1999 to December 2002. We calculate cross-correlation functions (CCFs) for eight available station pairs at frequency bands of 0.4-0.8 Hz and 0.8-1.6 Hz, and retrieve the Rayleigh waves propagating with a group velocity of about 1.0 km/s. Comparing CCFs obtained for each day with the reference CCFs that are calculated from a few months of data, we estimate seismic velocity changes before and after the 2000 activity. Results at the two frequency bands show seismic velocity increase and decrease. Shallow structure at the volcanic edifice on the flanks experienced a seismic velocity increase up to 3.3%. On the other hand, the regions located close to the collapsed caldera show a seismic velocity decrease down to 2.3%. To understand the mechanisms that may introduce these seismic velocity increase and decrease, we examine several possible mechanisms of the velocity changes: stress changes due to volcanic pressure sources and caldera formation, and topographic changes. By using the deflation sources previously determined from GPS data, we calculate the stresses at depths of 0 km and 1 km at the volcano. The results suggest that the seismic velocity increases observed at seismic paths on the volcanic flank are explained by the compression caused by the deflation sources associated with magma activity in 2000. Stress sensitivities of the seismic velocity changes are estimated to be 1.5 × 10- 2 to 2.2 × 10- 2 MPa- 1 and 4.6 × 10- 3 to 2.4 × 10- 2 MPa- 1 at frequency bands of 0.4-0.8 Hz and 0.8-1.6 Hz, respectively, which are in the range of the previously reported results. Our three

  18. Derivation of site-specific relationships between hydraulic parameters and p-wave velocities based on hydraulic and seismic tomography

    Energy Technology Data Exchange (ETDEWEB)

    Brauchler, R.; Doetsch, J.; Dietrich, P.; Sauter, M.

    2012-01-10

    In this study, hydraulic and seismic tomographic measurements were used to derive a site-specific relationship between the geophysical parameter p-wave velocity and the hydraulic parameters, diffusivity and specific storage. Our field study includes diffusivity tomograms derived from hydraulic travel time tomography, specific storage tomograms, derived from hydraulic attenuation tomography, and p-wave velocity tomograms, derived from seismic tomography. The tomographic inversion was performed in all three cases with the SIRT (Simultaneous Iterative Reconstruction Technique) algorithm, using a ray tracing technique with curved trajectories. The experimental set-up was designed such that the p-wave velocity tomogram overlaps the hydraulic tomograms by half. The experiments were performed at a wellcharacterized sand and gravel aquifer, located in the Leine River valley near Göttingen, Germany. Access to the shallow subsurface was provided by direct-push technology. The high spatial resolution of hydraulic and seismic tomography was exploited to derive representative site-specific relationships between the hydraulic and geophysical parameters, based on the area where geophysical and hydraulic tests were performed. The transformation of the p-wave velocities into hydraulic properties was undertaken using a k-means cluster analysis. Results demonstrate that the combination of hydraulic and geophysical tomographic data is a promising approach to improve hydrogeophysical site characterization.

  19. Joint inversion of seismic and gravity data for imaging seismic velocity structure of the crust and upper mantle beneath Utah, United States

    Science.gov (United States)

    Syracuse, E. M.; Zhang, H.; Maceira, M.

    2017-10-01

    We present a method for using any combination of body wave arrival time measurements, surface wave dispersion observations, and gravity data to simultaneously invert for three-dimensional P- and S-wave velocity models. The simultaneous use of disparate data types takes advantage of the differing sensitivities of each data type, resulting in a comprehensive and higher resolution three-dimensional geophysical model. In a case study for Utah, we combine body wave first arrivals mainly from the USArray Transportable Array, Rayleigh wave group and phase velocity dispersion data, and Bouguer gravity anomalies to invert for crustal and upper mantle structure of the region. Results show clear delineations, visible in both P- and S-wave velocities, between the three main tectonic provinces in the region. Without the inclusion of the surface wave and gravity constraints, these delineations are less clear, particularly for S-wave velocities. Indeed, checkerboard tests confirm that the inclusion of the additional datasets dramatically improves S-wave velocity recovery, with more subtle improvements to P-wave velocity recovery, demonstrating the strength of the method in successfully recovering seismic velocity structure from multiple types of constraints.

  20. STUDY OF TIME LAPSE IN FOREIGN BODY ASPIRATION IN RELATION TO CHEST X - RAY AND TYPE OF FOREIGN BODY

    Directory of Open Access Journals (Sweden)

    Salma

    2015-10-01

    Full Text Available INTRODUCTI ON: Foreign body aspiration in pediatrics is a potentially fatal accident which will continue until children explore their surroundings with their hand and mouth. Pediatric aspirations will persist until mankind exists. Not all foreign body aspirations are witnessed hence chances of delay in diagnosing an aspiration are high. Delay in diagnosis depends on site and character of foreign body aspirated. The chest x - ray findings and type of foreign body extracted vary depending on the duration the foreign body remains in airway . OBJECTIVE: To study the X - ray finding in pediatric airway aspiration and its relation to time lapse, the type and site of lodgment of foreign body extracted via bronchoscopy. The type of foreign body in relation to time lapse in aspiration. MATERIAL AND METHODS: This was a prospective study done in Bapuji child health institute and research center, JJM Medical College, Davangere . History and pre bronchoscopy x - Ray finding were noted for 65 children who were posted for suspicious bronchoscopy from August 2011 to September 2013. 11 children were excluded from study as they showed no foreign body on bronchoscopy. Time lapse in aspir ation and seeking medical care was noted. The bronchoscopic findings regarding site of foreign body lodgment and type of foreign body were recorded. The type of foreign body and variation of x - ray picture in relation to time lapse in aspiration were noted. Data collected was analyzed using descriptive statistics. RESULT: It was observed that mean age was 28 months. About 80% of the cases were between 1 to 3 years age. 82% (n=53/54 were radio lucent foreign body, only 1.5% (n=1/54 were radio o paque. Site of lodgment of foreign body was right main bronchus in 48% (n=26/54, left main bronchus 46% (n=25/54 , tracheal 1.85% (n=1/54, subglottic 1.85% (n=1/54, carinal 1.85% (n=1/54, multiple site i.e. left bronchus +right bronchus+ carinal 1.85% (n=1/54. Groundnut was most common

  1. Anatomy of a caldera: seismic velocity and attenuation models of the Campi Flegrei (Italy).

    Science.gov (United States)

    Calò, Marco; Tramelli, Anna

    2017-04-01

    Campi Flegrei is an active Caldera marked by strong vertical deformations of the soil called bradyseisms. The mechanisms proposed to explain this phenomenon are essentially three i) the presence of a shallow magmatic chamber that pushes the lid and consequently producing periodic variation of the soil level, ii) a thermic expansion of the geothermal aquifer due to the periodic increase of heat flux coming from a near magmatic chamber or deep fluids or iii) a combination of both phenomena. To solve the paradox, several models have been proposed to describe the nature and the geometry of the bodies responsible of the bradyseisms. Seismological tools allowed a rough description of the main features in terms of seismic velocities and attenuation parameters and till now were not able to resolve the smallest structures (water saturated reservoir from regions with low Vp, low Vp/Vs and low Qp possibly related to the gas saturated part of the reservoir. At deeper depth (2-3.5 km) bodies with high Vp and Vp/Vs and low Qp can be associated with magmatic intrusions. The results of this project have been obtained in the framework of the PIPIIT program (IA100416).

  2. Crustal seismicity and the earthquake catalog maximum moment magnitudes (Mcmax) in stable continental regions (SCRs): correlation with the seismic velocity of the lithosphere

    Science.gov (United States)

    Mooney, Walter D.; Ritsema, Jeroen; Hwang, Yong Keun

    2012-01-01

    A joint analysis of global seismicity and seismic tomography indicates that the seismic potential of continental intraplate regions is correlated with the seismic properties of the lithosphere. Archean and Early Proterozoic cratons with cold, stable continental lithospheric roots have fewer crustal earthquakes and a lower maximum earthquake catalog moment magnitude (Mcmax). The geographic distribution of thick lithospheric roots is inferred from the global seismic model S40RTS that displays shear-velocity perturbations (δVS) relative to the Preliminary Reference Earth Model (PREM). We compare δVS at a depth of 175 km with the locations and moment magnitudes (Mw) of intraplate earthquakes in the crust (Schulte and Mooney, 2005). Many intraplate earthquakes concentrate around the pronounced lateral gradients in lithospheric thickness that surround the cratons and few earthquakes occur within cratonic interiors. Globally, 27% of stable continental lithosphere is underlain by δVS≥3.0%, yet only 6.5% of crustal earthquakes with Mw>4.5 occur above these regions with thick lithosphere. No earthquakes in our catalog with Mw>6 have occurred above mantle lithosphere with δVS>3.5%, although such lithosphere comprises 19% of stable continental regions. Thus, for cratonic interiors with seismically determined thick lithosphere (1) there is a significant decrease in the number of crustal earthquakes, and (2) the maximum moment magnitude found in the earthquake catalog is Mcmax=6.0. We attribute these observations to higher lithospheric strength beneath cratonic interiors due to lower temperatures and dehydration in both the lower crust and the highly depleted lithospheric root.

  3. Crustal seismicity and the earthquake catalog maximum moment magnitude (Mcmax) in stable continental regions (SCRs): Correlation with the seismic velocity of the lithosphere

    Science.gov (United States)

    Mooney, Walter D.; Ritsema, Jeroen; Hwang, Yong Keun

    2012-12-01

    A joint analysis of global seismicity and seismic tomography indicates that the seismic potential of continental intraplate regions is correlated with the seismic properties of the lithosphere. Archean and Early Proterozoic cratons with cold, stable continental lithospheric roots have fewer crustal earthquakes and a lower maximum earthquake catalog moment magnitude (Mcmax). The geographic distribution of thick lithospheric roots is inferred from the global seismic model S40RTS that displays shear-velocity perturbations (δVS) relative to the Preliminary Reference Earth Model (PREM). We compare δVS at a depth of 175 km with the locations and moment magnitudes (Mw) of intraplate earthquakes in the crust (Schulte and Mooney, 2005). Many intraplate earthquakes concentrate around the pronounced lateral gradients in lithospheric thickness that surround the cratons and few earthquakes occur within cratonic interiors. Globally, 27% of stable continental lithosphere is underlain by δVS≥3.0%, yet only 6.5% of crustal earthquakes with Mw>4.5 occur above these regions with thick lithosphere. No earthquakes in our catalog with Mw>6 have occurred above mantle lithosphere with δVS>3.5%, although such lithosphere comprises 19% of stable continental regions. Thus, for cratonic interiors with seismically determined thick lithosphere (1) there is a significant decrease in the number of crustal earthquakes, and (2) the maximum moment magnitude found in the earthquake catalog is Mcmax=6.0. We attribute these observations to higher lithospheric strength beneath cratonic interiors due to lower temperatures and dehydration in both the lower crust and the highly depleted lithospheric root.

  4. Understanding infiltration and groundwater flow at an artificial recharge facility using time-lapse gravity data

    Science.gov (United States)

    Kennedy, Jeffrey

    Groundwater provides a fundamental resource for modern life. Throughout the world, groundwater is managed by storing (recharging) it underground in natural aquifers for future withdrawal and consumptive use. In Arizona, over 4 million people benefit from managed aquifer storage, but little effort is made to track the movement of recharged water through the subsurface. Motivated by current limitations in our ability to monitor percolation and groundwater movement at the scale of a recharge facility, an effort to collect time-lapse gravity data was carried out at the Southern Avra Valley Storage and Recovery Project (SAVSARP) operated by the City of Tucson, Arizona. In addition to collecting water-level data 12 wells, there were three primary gravity experiments: (1) five continuously-recording gravity meters (2 iGrav superconducting gravity meters and 3 gPhone gravity meters) were installed semi-permanently in control buildings adjacent to the recharge basins, (2) absolute gravity measurements were made at nine locations over a 17 month period, and (3) three relative-gravity campaigns were carried out on a network of 70 stations. This large-scale controlled experiment, with known infiltration and pumping rates, resulted in one of the most comprehensive datasets of its kind. Gravity data led to several hydrologic insights, both through direct measurement and modeling. First, the infiltration rate could be estimated accurately based on the initial rate of gravity change during infiltration, regardless of the specific yield. Using two gravity meters, the depth, and therefore speed, of the wetting front beneath a recharge basin was observed, including the time at which the water table was reached. Spatial maps of gravity change from relative gravity surveys show areas where infiltration efficiency is highest, and where groundwater accumulates; storage accumulated preferentially to the west of the recharge basins, away from pumping wells. Such information would be

  5. Seismic Velocity Changes in the Backarc Continental Crust After the 2011 Mw 9.0 Tohoku-Oki Megathrust Earthquake

    Science.gov (United States)

    Hong, Tae-Kyung; Lee, Junhyung; Chi, Donggeun; Park, Seongjun

    2017-11-01

    The 2011 Mw 9.0 Tohoku-Oki megathrust earthquake accompanied coseismic and postseismic displacements around the eastern Eurasian continental plate. Noise cross correlations produced transient seismic waveforms along interstation paths in the Korean Peninsula. We measured the traveltime changes of the fundamental mode Rayleigh waves over the range of 0.03-0.08 Hz after the megathrust earthquake. The temporal seismic velocity changes in the lower crust were assessed from the traveltime changes. The traveltimes increased instantly after the megathrust earthquake and were gradually recovered over several hundreds to thousands of days. The instant shear wave velocity decreases ranged between 0.731 (±0.057)% and 4.068 (±0.173)%. The temporal medium perturbation might be caused by the transient uniaxial tensional stress due to the coseismic and postseismic displacements. The medium properties may be recovered by progressive stress field reconstruction.

  6. Time-Lapse Seismic Monitoring and Performance Assessment of CO2 Sequestration in Hydrocarbon Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Datta-Gupta, Akhil [Texas Engineering Experiment Station, College Station, TX (United States)

    2017-06-15

    Carbon dioxide sequestration remains an important and challenging research topic as a potentially viable approach for mitigating the effects of greenhouse gases on global warming (e.g., Chu and Majumdar, 2012; Bryant, 2007; Orr, 2004; Hepple and Benson, 2005; Bachu, 2003; Grimston et al., 2001). While CO2 can be sequestered in oceanic or terrestrial biomass, the most mature and effective technology currently available is sequestration in geologic formations, especially in known hydrocarbon reservoirs (Barrufet et al., 2010; Hepple and Benson, 2005). However, challenges in the design and implementation of sequestration projects remain, especially over long time scales. One problem is that the tendency for gravity override caused by the low density and viscosity of CO2. In the presence of subsurface heterogeneity, fractures and faults, there is a significant risk of CO2 leakage from the sequestration site into overlying rock compared to other liquid wastes (Hesse and Woods, 2010; Ennis-King and Patterson, 2002; Tsang et al., 2002). Furthermore, the CO2 will likely interact chemically with the rock in which it is stored, so that understanding and predicting its transport behavior during sequestration can be complex and difficult (Mandalaparty et al., 2011; Pruess et al., 2003). Leakage of CO2 can lead to such problems as acidification of ground water and killing of plant life, in addition to contamination of the atmosphere (Ha-Duong, 2003; Gasda et al., 2004). The development of adequate policies and regulatory systems to govern sequestration therefore requires improved characterization of the media in which CO2 is stored and the development of advanced methods for detecting and monitoring its flow and transport in the subsurface (Bachu, 2003).

  7. Joint inversion of teleseismic P waveforms and surface-wave group velocities from ambient seismic noise in the Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Růžek, Bohuslav; Plomerová, Jaroslava; Babuška, Vladislav

    2012-01-01

    Roč. 56, č. 1 (2012), s. 107-140 ISSN 0039-3169 R&D Projects: GA ČR GA205/07/1088; GA AV ČR IAA300120709; GA MŠk LM2010008 Institutional research plan: CEZ:AV0Z30120515 Keywords : receiver function * seismic noise * joint inversion * Bohemian Massif * velocity structure Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.975, year: 2012

  8. 2.5D seismic velocity modelling in the south-eastern Romanian Carpathians Orogen and its foreland

    Science.gov (United States)

    Bocin, Andrei; Stephenson, Randell; Tryggvason, Ari; Panea, Ionelia; Mocanu, Victor; Hauser, Franz; Matenco, Liviu

    2005-12-01

    The DACIA-PLAN (Danube and Carpathian Integrated Action on Processes in the Lithosphere and Neotectonics) deep seismic reflection survey was performed in August-September 2001, with the objective of obtaining new information on the deep structure of the external Carpathians nappe system and the architecture of the Tertiary/Quaternary basins developed within and adjacent to the Vrancea zone, including the rapidly subsiding Focsani Basin. The DACIA-PLAN profile is about 140 km long, having a roughly WNW-ESE direction, from near the southeast Transylvanian Basin, across the mountainous south-eastern Carpathians and their foreland to near the Danube River. A high resolution 2.5D velocity model of the upper crust along the seismic profile has been determined from a tomographic inversion of the DACIA-PLAN first arrival data. The results show that the data fairly accurately resolve the transition from sediment to crystalline basement beneath the Focsani Basin, where industry seismic data are available for correlation, at depths up to about 10 km. Beneath the external Carpathians nappes, apparent basement (material with velocities above 5.8 km/s) lies at depths as shallow as 3-4 km, which is less than previously surmised on the basis of geological observations. The first arrival travel-time data suggest that there is significant lateral structural heterogeneity on the apparent basement surface in this area, suggesting that the high velocity material may be involved in Carpathian thrusting.

  9. Evaluation of the rockburst potential in longwall coal mining using passive seismic velocity tomography and image subtraction technique

    Science.gov (United States)

    Hosseini, Navid

    2017-09-01

    Rockburst is a typical dynamic disaster in underground coal mines which its occurrences relate to the mechanical quality of coal seam and surrounding rock mass and also the condition of stress distribution. The main aim of this paper is to study the potential of rockburst in a longwall coal mine by using of passive seismic velocity tomography and image subtraction technique. For this purpose, first by mounting an array of receivers on the surface above the active panel, the mining-induced seismic data as a passive source for several continuous days were recorded. Then, the three-dimensional tomograms using simultaneous iteration reconstruction technique (SIRT) for each day are created and by employing the velocity filtering, the overstressed zones are detected. In addition, the two-dimensional seismic velocity tomograms in coal seam level by slicing the three-dimensional tomograms are obtained. Then the state of stress changes in successive days by applying the image subtraction technique on these two-dimensional tomograms is considered. The results show that the compilation of filtered three-dimensional tomograms and subtracted images is an appropriate approach for detecting the overstressed zones around the panel and subsequent evaluation of rockburst potential. The research conclusion proves that the applied approach in this study in combination with field observations of rock mass status can effectively identify the rockburst-prone areas during the mining operation and help to improve the safety condition.

  10. Spatiotemporal monitoring of soil water content profiles in an irrigated field using probabilistic inversion of time-lapse EMI data

    KAUST Repository

    Moghadas, Davood

    2017-10-17

    Monitoring spatiotemporal variations of soil water content (θ) is important across a range of research fields, including agricultural engineering, hydrology, meteorology and climatology. Low frequency electromagnetic induction (EMI) systems have proven to be useful tools in mapping soil apparent electrical conductivity (σa) and soil moisture. However, obtaining depth profile water content is an area that has not been fully explored using EMI. To examine this, we performed time-lapse EMI measurements using a CMD mini-Explorer sensor along a 10 m transect of a maize field over a 6 day period. Reference data were measured at the end of the profile via an excavated pit using 5TE capacitance sensors. In order to derive a time-lapse, depth-specific subsurface image of electrical conductivity (σ), we applied a probabilistic sampling approach, DREAM(ZS), on the measured EMI data. The inversely estimated σ values were subsequently converted to θ using the Rhoades et al. (1976) petrophysical relationship. The uncertainties in measured σa, as well as inaccuracies in the inverted data, introduced some discrepancies between estimated σ and reference values in time and space. Moreover, the disparity between the measurement footprints of the 5TE and CMD Mini-Explorer sensors also led to differences. The obtained θ permitted an accurate monitoring of the spatiotemporal distribution and variation of soil water content due to root water uptake and evaporation. The proposed EMI measurement and modeling technique also allowed for detecting temporal root zone soil moisture variations. The time-lapse θ monitoring approach developed using DREAM(ZS) thus appears to be a useful technique to understand spatiotemporal patterns of soil water content and provide insights into linked soil moisture vegetation processes and the dynamics of soil moisture/infiltration processes.

  11. Effect of time lapse on the diagnostic accuracy of cone beam computed tomography for detection of vertical root fractures

    Energy Technology Data Exchange (ETDEWEB)

    Eskandarloo, Amir; Shokri, Abbas, E-mail: Dr.a.shokri@gmail.com [Dental Research Center, Department of Oral and Maxillofacial Radiology, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Asl, Amin Mahdavi [Department of Oral and Maxillofacial Radiology, Golestan University of Medical Sciences, Gorgan (Iran, Islamic Republic of); Jalalzadeh, Mohsen [Department of Endodontics, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Tayari, Maryam [Department of Pedodontics, Golestan University of Medical Sciences, Gorgan (Iran, Islamic Republic of); Hosseinipanah, Mohammad [Department of Anatomy, School of Medicine, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Fardmal, Javad [Research Center for Health Sciences and Department of Epidemiology and Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of)

    2016-01-15

    Accurate and early diagnosis of vertical root fractures (VRFs) is imperative to prevent extensive bone loss and unnecessary endodontic and prosthodontic treatments. The aim of this study was to assess the effect of time lapse on the diagnostic accuracy of cone beam computed tomography (CBCT) for VRFs in endodontically treated dog’s teeth. Forty eight incisors and premolars of three adult male dogs underwent root canal therapy. The teeth were assigned to two groups: VRFs were artificially induced in the first group (n=24) while the teeth in the second group remained intact (n=24). The CBCT scans were obtained by NewTom 3G unit immediately after inducing VRFs and after one, two, three, four, eight, 12 and 16 weeks. Three oral and maxillofacial radiologists blinded to the date of radiographs assessed the presence/absence of VRFs on CBCT scans. The sensitivity, specificity and accuracy values were calculated and data were analyzed using SPSS v.16 software and ANOVA. The total accuracy of detection of VRFs immediately after surgery, one, two, three, four, eight, 12 and 16 weeks was 67.3%, 68.7%, 66.6%, 64.6%, 64.5%, 69.4%, 68.7%, 68% respectively. The effect of time lapse on detection of VRFs was not significant (p>0.05). Overall sensitivity, specificity and accuracy of CBCT for detection of VRFs were 74.3%, 62.2%, 67.2% respectively. Cone beam computed tomography is a valuable tool for detection of VRFs. Time lapse (four months) had no effect on detection of VRFs on CBCT scans. (author)

  12. Analysis of Zebrafish Kidney Development with Time-lapse Imaging Using a Dissecting Microscope Equipped for Optical Sectioning.

    Science.gov (United States)

    Perner, Birgit; Schnerwitzki, Danny; Graf, Michael; Englert, Christoph

    2016-04-07

    In order to understand organogenesis, the spatial and temporal alterations that occur during development of tissues need to be recorded. The method described here allows time-lapse analysis of normal and impaired kidney development in zebrafish embryos by using a fluorescence dissecting microscope equipped for structured illumination and z-stack acquisition. To visualize nephrogenesis, transgenic zebrafish (Tg(wt1b:GFP)) with fluorescently labeled kidney structures were used. Renal defects were triggered by injection of an antisense morpholino oligonucleotide against the Wilms tumor gene wt1a, a factor known to be crucial for kidney development. The advantage of the experimental setup is the combination of a zoom microscope with simple strategies for re-adjusting movements in x, y or z direction without additional equipment. To circumvent focal drift that is induced by temperature variations and mechanical vibrations, an autofocus strategy was applied instead of utilizing a usually required environmental chamber. In order to re-adjust the positional changes due to a xy-drift, imaging chambers with imprinted relocation grids were employed. In comparison to more complex setups for time-lapse recording with optical sectioning such as confocal laser scanning or light sheet microscopes, a zoom microscope is easy to handle. Besides, it offers dissecting microscope-specific benefits such as high depth of field and an extended working distance. The method to study organogenesis presented here can also be used with fluorescence stereo microscopes not capable of optical sectioning. Although limited for high-throughput, this technique offers an alternative to more complex equipment that is normally used for time-lapse recording of developing tissues and organ dynamics.

  13. Spatiotemporal monitoring of soil water content profiles in an irrigated field using probabilistic inversion of time-lapse EMI data

    Science.gov (United States)

    Moghadas, Davood; Jadoon, Khan Zaib; McCabe, Matthew F.

    2017-12-01

    Monitoring spatiotemporal variations of soil water content (θ) is important across a range of research fields, including agricultural engineering, hydrology, meteorology and climatology. Low frequency electromagnetic induction (EMI) systems have proven to be useful tools in mapping soil apparent electrical conductivity (σa) and soil moisture. However, obtaining depth profile water content is an area that has not been fully explored using EMI. To examine this, we performed time-lapse EMI measurements using a CMD mini-Explorer sensor along a 10 m transect of a maize field over a 6 day period. Reference data were measured at the end of the profile via an excavated pit using 5TE capacitance sensors. In order to derive a time-lapse, depth-specific subsurface image of electrical conductivity (σ), we applied a probabilistic sampling approach, DREAM(ZS) , on the measured EMI data. The inversely estimated σ values were subsequently converted to θ using the Rhoades et al. (1976) petrophysical relationship. The uncertainties in measured σa, as well as inaccuracies in the inverted data, introduced some discrepancies between estimated σ and reference values in time and space. Moreover, the disparity between the measurement footprints of the 5TE and CMD Mini-Explorer sensors also led to differences. The obtained θ permitted an accurate monitoring of the spatiotemporal distribution and variation of soil water content due to root water uptake and evaporation. The proposed EMI measurement and modeling technique also allowed for detecting temporal root zone soil moisture variations. The time-lapse θ monitoring approach developed using DREAM(ZS) thus appears to be a useful technique to understand spatiotemporal patterns of soil water content and provide insights into linked soil moisture vegetation processes and the dynamics of soil moisture/infiltration processes.

  14. Obstetric and perinatal outcomes of pregnancies conceived with embryos cultured in a time-lapse monitoring system.

    Science.gov (United States)

    Insua, Maria Fernanda; Cobo, Ana Cristina; Larreategui, Zaloa; Ferrando, Marcos; Serra, Vicente; Meseguer, Marcos

    2017-09-01

    To compare obstetric and perinatal outcomes of singleton pregnancies resulting from embryos incubated in a time-lapse system (TLS) with those of embryos grown in standard IVF incubators (SI). Retrospective description of a cohort of patients who conceived during a randomized, controlled trial. Private university-affiliated IVF center. Of 856 randomized patients, 378 gave birth to a live-born infant: 216 of the deliveries originated from embryos incubated in TLS, and 162 deliveries were from embryos cultured in SI. Embryo incubation and selection in TLS. Delivery and neonatal outcomes. No significant differences were observed in the baseline characteristics of the study population. The delivery rate was 49.3% (TLS) vs. 40.0% (SI), and multiple deliveries were higher in the TLS group: 31.0% (67 of 216) vs. 24.7% (40 of 162) in the SI group. When singleton pregnancies were analyzed no differences were found between the two groups in the rate of obstetric problems with respect to weeks at delivery: 38.8 (95% confidence interval [CI] 38.4-39.1) (TLS) vs. 39.5 (95% CI 38.0-39.9) (SI); preterm births (outcomes such as birth weight: 3,163 g (95% CI 3,035-3,292 g) (TLS) vs. 3,074 (95% CI 2,913-3,236) (SI); low birth weight (obstetric and perinatal outcomes when a time-lapse incubator was used rather than a more widely used conventional incubator. As far as we know this is the first report from a randomized study of the neonatal outcomes of time-lapse monitoring. Our results suggest that this technology is an effective and safe alternative for embryo incubation, though trials of larger numbers of patients are required to further confirm our conclusions. NCT01549262. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  15. Near real-time imaging of molasses injections using time-lapse electrical geophysics at the Brandywine DRMO, Brandywine, Maryland

    Science.gov (United States)

    Versteeg, R. J.; Johnson, T.; Major, B.; Day-Lewis, F. D.; Lane, J. W.

    2010-12-01

    Enhanced bioremediation, which involves introduction of amendments to promote biodegradation, increasingly is used to accelerate cleanup of recalcitrant compounds and has been identified as the preferred remedial treatment at many contaminated sites. Although blind introduction of amendments can lead to sub-optimal or ineffective remediation, the distribution of amendment throughout the treatment zone is difficult to measure using conventional sampling. Because amendments and their degradation products commonly have electrical properties that differ from those of ambient soil, time-lapse electrical geophysical monitoring has the potential to verify amendment emplacement and distribution. In order for geophysical monitoring to be useful, however, results of the injection ideally should be accessible in near real time. In August 2010, we demonstrated the feasibility of near real-time, autonomous electrical geophysical monitoring of amendment injections at the former Defense Reutilization and Marketing Office (DRMO) in Brandywine, Maryland. Two injections of about 1000 gallons each of molasses, a widely used amendment for enhanced bioremediation, were monitored using measurements taken with borehole and surface electrodes. During the injections, multi-channel resistance data were recorded; data were transmitted to a server and processed using a parallel resistivity inversion code; and results in the form of time-lapse imagery subsequently were posted to a website. This process occurred automatically without human intervention. The resulting time-lapse imagery clearly showed the evolution of the molasses plume. The delay between measurements and online delivery of images was between 45 and 60 minutes, thus providing actionable information that could support decisions about field procedures and a check on whether amendment reached target zones. This experiment demonstrates the feasibility of using electrical imaging as a monitoring tool both during amendment emplacement

  16. Laboratory Permeability and Seismic velocity anisotropy measurements across the Alpine Fault, New Zealand

    Science.gov (United States)

    Faulkner, D.; Allen, M. J.; Tatham, D.; Mariani, E.; Boulton, C. J.

    2015-12-01

    The Alpine Fault, a transpressional plate boundary between the Australia-Pacific plates, is known to rupture periodically (200-400yr) with large magnitude earthquakes (Mw~8) and is currently nearing the end of its latest interseismic period. The hydraulic and elastic properties of fault zones influence the nature and style of earthquake rupture and associated processes; investigating these properties in Alpine Fault rocks yields insights into conditions late in the seismic cycle. We present a suite of laboratory permeability and P (Vp) and S (Vs) wave velocity measurements preformed on diverse fault rock lithologies recovered during the first phase of the Deep Fault Drilling Project (DFDP-1). DFDP-1 drilled two boreholes reaching depths of 100.6m and 151.4m and retrieved fault rocks from both the hanging wall and footwall, including ultramylonites, ultracomminuted gouges and variably foliated and unfoliated cataclasites. Drilling revealed a typical shallow fault structure: localised principal slip zones (PSZ) of gouge nested within a damage zone overprinted by a zone of alteration, a record of enhanced fluid-rock interaction. Core material was tested in three orthogonal directions, orientated relative to the down core axis and, when present, foliation. Measurements were conducted with pore pressure held at 5MPa over an effective pressure (Peff) range of 5-105MPa, equivalent to pressure conditions down to ~7km depth. Using the Pulse Transient technique permeabilities at Peff=5MPa range from 10-17 to 10-20m2, decreasing to 10-18 to 10-21m2 at Peff=105MPa. Vp and Vs decrease with increased proximity to the PSZ with Vp in the hanging wall spanning 4500-5900m/s, dropping to 3900-4200m/s at the PSZ and then increasing to 4400-5600m/s in the foot wall. Wave velocities and permeability are enhanced parallel to tectonic fabrics e.g. foliation defined by aligned phyllosillicates and quartz- feldspar clasts. These measurements constrain interseismic conditions within the

  17. Crustal structure beneath discovery bank in the South Scotia Sea from group velocity tomography and seismic reflection data

    International Nuclear Information System (INIS)

    Vuan, A.; Lodolo, E.; Panza, G.F.

    2003-09-01

    Bruce, Discovery, Herdman and Jane Banks, all located along the central-eastern part of the South Scotia Ridge (i.e., the Antarctica-Scotia plate boundary), represent isolated topographic reliefs surrounded by relatively young oceanic crust, whose petrological and structural nature is still the subject of speculations due to the lack of resolving data. In the Scotia Sea and surrounding regions negative anomalies of about 34% are reported in large-scale group velocity tomography maps. The spatial resolution (∼500 km) of these maps does not warrant any reliable interpretation of such anomalies. A recent surface wave tomography in the same area, performed using broad band seismic stations and 300 regional events, shows that in the period range from 15 s to 50 s the central-eastern part of the South Scotia Ridge is characterized by negative anomalies of the group velocities as large as 6. The resolution of our data set (∼300 km) makes it possible to distinguish an area (centered at 61 deg S and 36 deg W) with a crust thicker than 25 km, and a shear wave velocity vs. depth profile similar to that found beneath the northern tip of the Antarctic Peninsula and southern South America. Rayleigh and Love wave dispersion curves are inverted in the period range from 15 s to 80 s to obtain shear wave velocity profiles that suggest a continental nature of Discovery Bank. The continental-type crust of this topographic relief is in agreement with the interpretation of a multi-channel seismic reflection profile acquired across this rise. Peculiar acoustic facies are observed in this profile and are interpreted as thinned and faulted continental plateau. The boundaries of the negative group velocity anomalies are marked by a high seismicity rate. Historical normal faulting earthquakes with magnitude around 7 are localised between the low velocity anomaly region in the eastern South Scotia Ridge and the high velocity anomaly region associated with the surrounding oceanic crust

  18. Soundscape and Noise Exposure Monitoring in a Marine Protected Area Using Shipping Data and Time-Lapse Footage.

    Science.gov (United States)

    Merchant, Nathan D; Pirotta, Enrico; Barton, Tim R; Thompson, Paul M

    2016-01-01

    We review recent work that developed new techniques for underwater noise assessment that integrate acoustic monitoring with automatic identification system (AIS) shipping data and time-lapse video, meteorological, and tidal data. Two sites were studied within the Moray Firth Special Area of Conservation (SAC) for bottlenose dolphins, where increased shipping traffic is expected from construction of offshore wind farms outside the SAC. Noise exposure varied markedly between the sites, and natural and anthropogenic contributions were characterized using multiple data sources. At one site, AIS-operating vessels accounted for total cumulative sound exposure (0.1-10 kHz), suggesting that noise modeling using the AIS would be feasible.

  19. Effects of seismic anisotropy on P-velocity tomography of the Baltic Shield

    Czech Academy of Sciences Publication Activity Database

    Eken, T.; Plomerová, Jaroslava; Vecsey, Luděk; Babuška, Vladislav; Roberts, R.; Shomali, H.; Bodvarsson, R.

    2012-01-01

    Roč. 188, č. 2 (2012), s. 600-612 ISSN 0956-540X R&D Projects: GA AV ČR IAA300120709 Institutional research plan: CEZ:AV0Z30120515 Keywords : body waves * seismic anisotropy * seismic tomography * cratons Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.853, year: 2012

  20. Evaluation of stress and saturation effects on seismic velocity and electrical resistivity - laboratory testing of rock samples

    Science.gov (United States)

    Vilhelm, Jan; Jirků, Jaroslav; Slavík, Lubomír; Bárta, Jaroslav

    2016-04-01

    Repository, located in a deep geological formation, is today considered the most suitable solution for disposal of spent nuclear fuel and high-level waste. The geological formations, in combination with an engineered barrier system, should ensure isolation of the waste from the environment for thousands of years. For long-term monitoring of such underground excavations special monitoring systems are developed. In our research we developed and tested monitoring system based on repeated ultrasonic time of flight measurement and electrical resistivity tomography (ERT). As a test site Bedřichov gallery in the northern Bohemia was selected. This underground gallery in granitic rock was excavated using Tunnel Boring Machine (TBM). The seismic high-frequency measurements are performed by pulse-transmission technique directly on the rock wall using one seismic source and three receivers in the distances of 1, 2 and 3 m. The ERT measurement is performed also on the rock wall using 48 electrodes. The spacing between electrodes is 20 centimeters. An analysis of relation of seismic velocity and electrical resistivity on water saturation and stress state of the granitic rock is necessary for the interpretation of both seismic monitoring and ERT. Laboratory seismic and resistivity measurements were performed. One series of experiments was based on uniaxial loading of dry and saturated granitic samples. The relation between stress state and ultrasonic wave velocities was tested separately for dry and saturated rock samples. Other experiments were focused on the relation between electrical resistivity of the rock sample and its saturation level. Rock samples with different porosities were tested. Acknowledgments: This work was partially supported by the Technology Agency of the Czech Republic, project No. TA 0302408

  1. A Trial for Detecting the Temporal Variation in Seismic Velocity Accompanied by a Slow Slip Event using Seismic Interferometry of Ambient Noise

    Science.gov (United States)

    Uemura, Miyuu; Ito, Yoshihiro; Ohta, Kazuaki; Hino, Ryota; Shinohara, Masanao

    2017-04-01

    Seismic interferometry is one of the most effective techniques to detect temporal variations in seismic velocity before or after a large earthquake. Some previous studies have been reported on seismic velocity reduction due to the occurrence of large earthquakes (e.g., Wegler et al., 2009; Yamada et al., 2010) as well as preceding them (e.g., Lockner et al., 1977; Yoshimitsu et al., 2009). However, there have only been a few studies thus far which attempt to detect seismic velocity changes associated with slow slip events (SSEs). In this study, we focus on applying seismic interferometry to ambient noise data from ocean bottom seismometers (OBSs) deployed near a subduction zone. Between the end of January 2011 and the largest foreshock occurring on March 9th that precedes the March 11, 2011 Tohoku-Oki earthquake, SSEs and low-frequency tremors were detected offshore Miyagi Prefecture (Ito et al., 2013, 2015; Katakami et al., 2016). We applied our seismic interferometry analysis using ambient noise to recordings from 17 OBS stations that were installed in the vicinity of the 2011 Tohoku-Oki earthquake source region, and only considered the recordings from before that major earthquake. All the OBSs are short-period seismometers with three components which have an eigenfrequency of 4.5 Hz. These OBSs were deployed offshore Miyagi Prefecture between November 2010 and April 2011. Before proceeding with the seismic interferometry analysis, we needed to estimate the two horizontal components of the original deployment orientation for 13 OBSs in (we could not estimate them for 4 OBSs). To obtain the OBS orientation, we used particle orbits of some direct P waves from selected tectonic earthquakes, in order to extract one vertical and two horizontal components. Then, the seismic interferometry analysis consisted of the following steps. First, we applied a band-pass filter of 0.25-2.0 Hz and one-bit technique to the ambient noise signal. Second, we calculated auto

  2. Relationship between the focal mechanism of magnitude ML 3.3 seismic event induced by mining and distribution of peak ground velocity

    Directory of Open Access Journals (Sweden)

    Dubiński Józef

    2017-01-01

    Full Text Available The relationship between seismic radiation pattern generated by a strong mining induced seismic event and the distribution of peak ground velocity in the epicenter area has been presented. It was a seismic event with the local magnitude ML = 3.3 occurred on June 21, 2016 in the Upper Silesian Coal Basin (USCB in Marcel Mine. Calculated values of the peak ground velocity, taking into account the amplification coefficient, were the basis for the development of the PGVHamp map. The resulting distribution of PGVHamp isolines and the measured velocity amplitudes point to significant differences. That fact indicates that some additional factors can impact on the seismic effect observed on the surface. One of them could be a focal mechanism of seismic event. Focal mechanism of the M=3.3 induced seismic tremor, were calculated by the moment tensor inversion method. The tremor was characterized by a normal slip mechanism with 87% shear component. Comparison of seismic pattern for S-wave at individual stations allowed confirms a relation between directionality of the seismic radiation pattern for S-wave and the recorded peak ground velocities and explain the observed anomaly.

  3. Seismic Technology Adapted to Analyzing and Developing Geothermal Systems Below Surface-Exposed High-Velocity Rocks Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Hardage, Bob A. [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; DeAngelo, Michael V. [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Ermolaeva, Elena [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Hardage, Bob A. [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Remington, Randy [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Sava, Diana [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Wagner, Donald [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Wei, Shuijion [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology

    2013-02-01

    The objective of our research was to develop and demonstrate seismic data-acquisition and data-processing technologies that allow geothermal prospects below high-velocity rock outcrops to be evaluated. To do this, we acquired a 3-component seismic test line across an area of exposed high-velocity rocks in Brewster County, Texas, where there is high heat flow and surface conditions mimic those found at numerous geothermal prospects. Seismic contractors have not succeeded in creating good-quality seismic data in this area for companies who have acquired data for oil and gas exploitation purposes. Our test profile traversed an area where high-velocity rocks and low-velocity sediment were exposed on the surface in alternating patterns that repeated along the test line. We verified that these surface conditions cause non-ending reverberations of Love waves, Rayleigh waves, and shallow critical refractions to travel across the earth surface between the boundaries of the fast-velocity and slow-velocity material exposed on the surface. These reverberating surface waves form the high level of noise in this area that does not allow reflections from deep interfaces to be seen and utilized. Our data-acquisition method of deploying a box array of closely spaced geophones allowed us to recognize and evaluate these surface-wave noise modes regardless of the azimuth direction to the surface anomaly that backscattered the waves and caused them to return to the test-line profile. With this knowledge of the surface-wave noise, we were able to process these test-line data to create P-P and SH-SH images that were superior to those produced by a skilled seismic data-processing contractor. Compared to the P-P data acquired along the test line, the SH-SH data provided a better detection of faults and could be used to trace these faults upward to the boundaries of exposed surface rocks. We expanded our comparison of the relative value of S-wave and P-wave seismic data for geothermal

  4. Love wave phase velocity models of the southeastern margin of Tibetan Plateau from a dense seismic array

    Science.gov (United States)

    Han, Fengqin; Jia, Ruizhi; Fu, Yuanyuan V.

    2017-08-01

    Love wave dispersion maps across the southeastern margin of the Tibetan Plateau are obtained using earthquake data recorded by the temporary ChinArray and permanent China Digital Seismic Array. Fundamental mode Love wave phase velocity curves are measured by inverting Love wave amplitude and phase with the two-plane-wave method. The phase velocity maps with resolution better than 150 km are presented at periods of 20-100 s, which is unprecedented in the study area. The maps agree well with each other and show clear correlations with major tectonic structures. The Love wave phase velocity could provide new information about structures in the crust and upper mantle beneath the southeast margin of Tibetan Plateau, like the radial anisotropy.

  5. Estimation of soil hydraulic parameters by integrated hydrogeophysical inversion of time-lapse GPR data measured at Selhausen, Germany

    KAUST Repository

    Jadoon, Khan

    2012-06-01

    We present an integrated hydrogeophysical inversion approach that uses time-lapse off-ground ground-penetrating radar (GPR) data to estimate soil hydraulic parameters, and apply it to a dataset collected in the field. Off-ground GPR data are mainly sensitive to the near-surface water content profile and dynamics, and are thus related to soil hydraulic parameters, such as the parameters of the hydraulic conductivity and water retention functions. The hydrological simulator HYDRUS 1-D was used with a two-layer single- and dual-porosity model. To monitor the soil water content dynamics, time-lapse GPR and time domain reflectometry (TDR) measurements were performed, whereby only GPR data was used in the inversion. The dual porosity model provided better results compared to the single porosity model for describing the soil water dynamics, which is supported by field observations of macropores. Furthermore, the GPR-derived water content profiles reconstructed from the integrated hydrogeophysical inversion were in good agreement with TDR observations. These results suggest that the proposed method is promising for non-invasive characterization of the shallow subsurface hydraulic properties and monitoring water dynamics at the field scale.

  6. Time-lapse imaging of primary preneoplastic mammary epithelial cells derived from genetically engineered mouse models of breast cancer.

    Science.gov (United States)

    Nakles, Rebecca E; Millman, Sarah L; Cabrera, M Carla; Johnson, Peter; Mueller, Susette; Hoppe, Philipp S; Schroeder, Timm; Furth, Priscilla A

    2013-02-08

    Time-lapse imaging can be used to compare behavior of cultured primary preneoplastic mammary epithelial cells derived from different genetically engineered mouse models of breast cancer. For example, time between cell divisions (cell lifetimes), apoptotic cell numbers, evolution of morphological changes, and mechanism of colony formation can be quantified and compared in cells carrying specific genetic lesions. Primary mammary epithelial cell cultures are generated from mammary glands without palpable tumor. Glands are carefully resected with clear separation from adjacent muscle, lymph nodes are removed, and single-cell suspensions of enriched mammary epithelial cells are generated by mincing mammary tissue followed by enzymatic dissociation and filtration. Single-cell suspensions are plated and placed directly under a microscope within an incubator chamber for live-cell imaging. Sixteen 650 μm x 700 μm fields in a 4x4 configuration from each well of a 6-well plate are imaged every 15 min for 5 days. Time-lapse images are examined directly to measure cellular behaviors that can include mechanism and frequency of cell colony formation within the first 24 hr of plating the cells (aggregation versus cell proliferation), incidence of apoptosis, and phasing of morphological changes. Single-cell tracking is used to generate cell fate maps for measurement of individual cell lifetimes and investigation of cell division patterns. Quantitative data are statistically analyzed to assess for significant differences in behavior correlated with specific genetic lesions.

  7. Accessing the uncertainties of seismic velocity and anisotropy structure of Northern Great Plains using a transdimensional Bayesian approach

    Science.gov (United States)

    Gao, C.; Lekic, V.

    2017-12-01

    Seismic imaging utilizing complementary seismic data provides unique insight on the formation, evolution and current structure of continental lithosphere. While numerous efforts have improved the resolution of seismic structure, the quantification of uncertainties remains challenging due to the non-linearity and the non-uniqueness of geophysical inverse problem. In this project, we use a reverse jump Markov chain Monte Carlo (rjMcMC) algorithm to incorporate seismic observables including Rayleigh and Love wave dispersion, Ps and Sp receiver function to invert for shear velocity (Vs), compressional velocity (Vp), density, and radial anisotropy of the lithospheric structure. The Bayesian nature and the transdimensionality of this approach allow the quantification of the model parameter uncertainties while keeping the models parsimonious. Both synthetic test and inversion of actual data for Ps and Sp receiver functions are performed. We quantify the information gained in different inversions by calculating the Kullback-Leibler divergence. Furthermore, we explore the ability of Rayleigh and Love wave dispersion data to constrain radial anisotropy. We show that when multiple types of model parameters (Vsv, Vsh, and Vp) are inverted simultaneously, the constraints on radial anisotropy are limited by relatively large data uncertainties and trade-off strongly with Vp. We then perform joint inversion of the surface wave dispersion (SWD) and Ps, Sp receiver functions, and show that the constraints on both isotropic Vs and radial anisotropy are significantly improved. To achieve faster convergence of the rjMcMC, we propose a progressive inclusion scheme, and invert SWD measurements and receiver functions from about 400 USArray stations in the Northern Great Plains. We start by only using SWD data due to its fast convergence rate. We then use the average of the ensemble as a starting model for the joint inversion, which is able to resolve distinct seismic signatures of

  8. 2D Seismic Velocity Modelling in the Southeastern Romanian Carpathians and its Foreland (Vrancea Zone and Focsani Basin)

    Science.gov (United States)

    Stephenson, R.; Bocin, A.; Tryggvason, A.

    2003-12-01

    The DACIA-PLAN (Danube and Carpathian Integrated Action on Processes in the Lithosphere and Neotectonics) deep seismic reflection survey was performed in August-September 2001, with the objective of obtaining of new information on the deep structure of the external Carpathians nappes and the architecture of Tertiary/Quaternary basins developed within and adjacent to the seismically-active Vrancea Zone, including the rapidly subsiding Focsani Basin. The DACIA-PLAN profile is about 140 km long, having a roughly NW-SE direction, from near the southeast Transylvanian Basin, across the mountainous southeastern Carpathians and their foreland to near the Danube Dalta. A high resolution 2D velocity model of the upper crust along the seismic profile has been determined from a first-arrival tomographic inversion of the DACIA-PLAN data. The shallowing of Palaeozoic-Mesozoic basement, and related structural heterogeneity within it, beneath the eastern flank of the Focsani Basin is clearly seen. Velocity heterogeneity within the Carpathian nappe belt is also evident and is indicative of internal structural complexity, including the presence of salt bodies and basement involvement in thrusting, thus favouring some current geological models over others. The presence of basement involvement implies the compressional reactivation of pre-existing basement normal faults. Members of the DACIA-PLAN/TomoSeis Working Group (see poster) should be considered as co-authors of this presentation.

  9. Spatio-temporal changes of seismic velocity at Miyakejima volcano associated with the 2000 eruption based on the cross-correlation analyses of ambient seismic noise records

    Science.gov (United States)

    Anggono, T.; Nishimura, T.; Sato, H.; Ueda, H.; Ukawa, M.

    2009-12-01

    and March - December 2002. At frequency band 0.4 - 0.8 Hz, we observe that station pairs surrounding the caldera show travel time difference decrease, which corresponds to seismic velocity increase, by -0.55 ± 2.45 % to -2.34 ± 2.06 %. Station pairs crossing or close to the caldera show travel time difference increase by 1.92 ± 1.37 % to 2.55 ± 1.36 %. At frequency band 0.8 - 1.6 Hz, we observe similar results except that the CCFs are not constructed well at station pairs crossing or close to the caldera. Spherical deflation sources determined by GPS data (Nishimura et al., 2002) can explain the seismic velocity increase observed at the volcano flank. By assuming a bulk modulus of 5 x 1010 Pa, we estimate that the stress sensitivities of velocity changes are ranging from 3.0 x 10-4 to 1.3 x 10-2 / MPa. However, the mechanism of seismic velocity decrease at station pairs crossing or close to the caldera cannot be explained by the deflation sources. The inconsistency may be explained by considering unknown pressure sources, seismic wave propagation across the formed caldera, or volcanic gas permeation into volcanic rocks.

  10. Noninvasive quantitative measurement of colloid transport in mesoscale porous media using time lapse fluorescence imaging.

    Science.gov (United States)

    Bridge, Jonathan W; Banwart, Steven A; Heathwaite, A Louise

    2006-10-01

    We demonstrate noninvasive quantitative imaging of colloid and solute transport at millimeter to decimeter (meso-) scale. Ultraviolet (UV) excited fluorescent solute and colloid tracers were independently measured simultaneously during co-advection through saturated quartz sand. Pulse-input experiments were conducted at constant flow rates and ionic strengths 10(-3), 10(-2) and 10(-1) M NaCl. Tracers were 1.9 microm carboxylate latex microspheres and disodium fluorescein. Spatial moments analysis was used to quantify relative changes in mass distribution of the colloid and solute tracers over time. The solute advected through the sand at a constant velocity proportional to flow rate and was described well by a conservative transport model (CXTFIT). In unfavorable deposition conditions increasing ionic strength produced significant reduction in colloid center of mass transport velocity over time. Velocity trends correlated with the increasing fraction of colloid mass retained along the flowpath. Attachment efficiencies (defined by colloid filtration theory) calculated from nondestructive retained mass data were 0.013 +/- 0.03, 0.09 +/- 0.02, and 0.22 +/- 0.05 at 10(-3), 10(-2), and 10(-1) M ionic strength, respectively, which compared well with previously published data from breakthrough curves and destructive sampling. Mesoscale imaging of colloid mass dynamics can quantify key deposition and transport parameters based on noninvasive, nondestructive, spatially high-resolution data.

  11. Construction method and application of 3D velocity model for evaluation of strong seismic motion and its cost performance

    International Nuclear Information System (INIS)

    Matsuyama, Hisanori; Fujiwara, Hiroyuki

    2014-01-01

    Based on experiences of making subsurface structure models for seismic strong motion evaluation, the advantages and disadvantages in terms of convenience and cost for several methods used to make such models were reported. As for the details, gravity and micro-tremor surveys were considered to be highly valid in terms of convenience and cost. However, stratigraphy and seismic velocity structure are required to make accurate 3-D subsurface structures. To realize these, methods for directly examining subsurface ground or using controlled tremor sources (at high cost) are needed. As a result, it was summarized that in modeling subsurface structures, some sort of plan including both types of methods is desirable and that several methods must be combined to match one's intended purposes and budget. (authors)

  12. Estimation of seismic velocity in the subducting crust of the Pacific slab beneath Hokkaido, northern Japan by using guided waves

    Science.gov (United States)

    Shiina, T.; Nakajima, J.; Toyokuni, G.; Kita, S.; Matsuzawa, T.

    2014-12-01

    A subducting crust contains a large amount of water as a form of hydrous minerals (e.g., Hacker et al., 2003), and the crust plays important roles for water transportation and seismogenesis in subduction zones at intermediate depths (e.g., Kirby et al., 1996; Iwamori, 2007). Therefore, the investigation of seismic structure in the crust is important to understand ongoing physical processes with subduction of oceanic lithosphere. A guided wave which propagates in the subducting crust is recorded in seismograms at Hokkaido, northern Japan (Shiina et al., 2014). Here, we estimated P- and S-wave velocity in the crust with guided waves, and obtained P-wave velocity of 6.6-7.3 km/s and S-wave velocity of 3.6-4.2 km/s at depths of 50-90 km. Moreover, Vp/Vs ratio in the crust is calculated to be 1.80-1.85 in that depth range. The obtained P-wave velocity about 6.6km/s at depths of 50-70 km is consistent with those estimated in Tohoku, northeast Japan (Shiina et al., 2013), and this the P-wave velocity is lower than those expected from models of subducting crustal compositions, such as metamorphosed MORB model (Hacker et al., 2003). In contrast, at greater depths (>80 km), the P-wave velocity marks higher velocity than the case of NE Japan and the velocity is roughly comparable to those of the MORB model. The obtained S-wave velocity distribution also shows characteristics similar to P waves. This regional variation may be caused by a small variation in thermal regime of the Pacific slab beneath the two regions as a result of the normal subduction in Tohoku and oblique subduction in Hokkaido. In addition, the effect of seismic anisotropy in the subducting crust would not be ruled out because rays used in the analysis in Hokkaido propagate mostly in the trench-parallel direction, while those in Tohoku are sufficiently criss-crossed.

  13. Low Velocity Seismic Waves Produced by Stick-Slip Processes During the Drainage of Two Supraglacial Lakes in Greenland

    Science.gov (United States)

    Kenyon, P. M.; Orantes, E. J.; Grynewize, S.; Tedesco, M.

    2016-12-01

    The drainage of supraglacial lakes over the Greenland ice sheet has been shown to have a significant impact on ice dynamics and subglacial hydrology. As supraglacial lakes drain, they produce seismic waves that can be detected on both local and regional scales. Studying such waves and the originating phenomena has the potential to advance our understanding of the subglacial processes involved. Here we present the results of an analysis of high frequency seismic waves generated during the drainage of two supraglacial lakes in southwestern Greenland. The two lakes drained by contrasting mechanisms. One (Lake Half Moon) drained slowly by overflow into an existing moulin. Here GPS data, recorded during the drainage, show an increase in ice sheet velocity that begins well before the time of maximum lake depth. The other lake (Lake Ponting) drained suddenly by hydrofracture through the lake bed. In this case, the GPS data show an increase in velocity that is essentially simultaneous with the maximum lake depth. In both cases, vertical component seismograms were obtained from the Greenland Ice Sheet Monitoring Network (GLISN) for several hours before and after the lake drainage. Arrival times were picked manually, using the criterion that an arrival must have a minimum amplitude of twice the noise level. The arrivals were then plotted on graphs of time versus distance from the lake in question. Several linear trends are visible on each graph. The velocities calculated from the slopes of these trends are unexpectedly low. We suggest that one explanation for this might be that the waves are traveling in a layer of till at the base of the ice sheet, that forms a low velocity channel. When compared with GPS and lake depth data, the origin times of the waves coincide with the velocity increase in both cases. Therefore, we conclude that the waves are being generated by stick-slip processes involving the slippage of the ice sheet on an underlying layer of till.

  14. Seismic Velocity Structure and Depth-Dependence of Anisotropy in the Red Sea and Arabian Shield from Surface Wave Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, S; Gaherty, J; Schwartz, S; Rodgers, A; Al-Amri, A

    2007-07-25

    We investigate the lithospheric and upper mantle structure as well as the depth-dependence of anisotropy along the Red Sea and beneath the Arabian Peninsula using receiver function constraints and phase velocities of surface waves traversing two transects of stations from the Saudi Arabian National Digital Seismic Network. Frequency-dependent phase delays of fundamental-mode Love and Rayleigh waves, measured using a cross-correlation procedure, require very slow shear velocities and the presence of anisotropy throughout the upper mantle. Linearized inversion of these data produce path-averaged 1D radially anisotropic models with about 4% anisotropy in the lithosphere, increasing to about 4.8% anisotropy across the lithosphere-asthenosphere boundary (LAB). Models with reasonable crustal velocities in which the mantle lithosphere is isotropic cannot satisfy the data. The lithospheric lid, which ranges in thickness from about 70 km near the Red Sea coast to about 90 km beneath the Arabian Shield, is underlain by a pronounced low-velocity zone with shear velocities as low as 4.1 km/s. Forward models, which are constructed from previously determined shear-wave splitting estimates, can reconcile surface and body wave observations of anisotropy. The low shear velocity values are similar to many other continental rift and oceanic ridge environments. These low velocities combined with the sharp velocity contrast across the LAB may indicate the presence of partial melt beneath Arabia. The anisotropic signature primarily reflects a combination of plate- and density-driven flow associated with active rifting processes in the Red Sea.

  15. Subsurface Hydrologic Processes Revealed by Time-lapse GPR in Two Contrasting Soils in the Shale Hills CZO

    Science.gov (United States)

    Guo, L.; Lin, H.; Nyquist, J.; Toran, L.; Mount, G.

    2017-12-01

    Linking subsurface structures to their functions in determining hydrologic processes, such as soil moisture dynamics, subsurface flow patterns, and discharge behaviours, is a key to understanding and modelling hydrological systems. Geophysical techniques provide a non-invasive approach to investigate this form-function dualism of subsurface hydrology at the field scale, because they are effective in visualizing subsurface structure and monitoring the distribution of water. In this study, we used time-lapse ground-penetrating radar (GPR) to compare the hydrologic responses of two contrasting soils in the Shale Hills Critical Zone Observatory. By integrating time-lapse GPR with artificial water injection, we observed distinct flow patterns in the two soils: 1) in the deep Rushtown soil (over 1.5 m depth to bedrock) located in a concave hillslope, a lateral preferential flow network extending as far as 2 m downslope was identified above a less permeable layer and via a series of connected macropores; whereas 2) in the shallow Weikert soil ( 0.3 m depth to saprock) located in a planar hillslope, vertical infiltration into the permeable fractured shale dominated the flow field, while the development of lateral preferential flow along the hillslope was restrained. At the Weikert soil site, the addition of brilliant blue dye to the water injection followed by in situ excavation supported GPR interpretation that only limited lateral preferential flow formed along the soil-saprock interface. Moreover, seasonally repeated GPR surveys indicated different patterns of profile moisture distribution in the two soils that in comparison with the dry season, a dense layer within the BC horizon in the deep Rushtown soil prevented vertical infiltration in the wet season, leading to the accumulation of soil moisture above this layer; whereas, in the shallow Weikert soil, water infiltrated into saprock in wet seasons, building up water storage within the fractured bedrock (i.e., the

  16. Variation of Seismic Velocity Structure around the Mantle Transition Zone and Conjecture of Deep Water Transport by Subducted Slabs

    Science.gov (United States)

    Tajima, F. C.; Stahler, S. C.; Ohtani, E.; Yoshida, M.; Sigloch, K.

    2011-12-01

    Seismic tomography models published in the past two decades determined common long-wavelength features of subducting plates as high velocity anomalies and upwelling plumes as low velocity anomalies, and have led to a new class of high-resolution three-dimensional (3D) modeling of global mantle convection with a link to tomography models [e.g., Becker and Boschi, 2002; Ritsema et al., 2007; Schuberth et al., 2009a,b]. However, even such high resolution numerical models do not account for the variation associated with different behaviors of subducting plates as they enter the mantle transition zone (MTZ), i.e., some flatten to form stagnant slabs with a large lateral extent and others descend further into the lower mantle. There are conventional interpretations applied for the cause of variation of the subducted slab behaviors, i.e., temperature difference due to different plate age, different geochemical compositions, different water content and subsequent possible reduction of viscosity etc., which could be taken as non-unique and somewhat equivocal. These parameters and conditions have been tested in two-dimensional numerical simulations, while the water content in the MTZ or the mechanisms of hydration and dehydration through subduction process are still in the realm of conjecture. Recent models of seismic P- and SH-wave velocities derived for the mantle structure beneath northeast China [Wang and Niu, 2010; Ye et al., 2011] using reflectivity synthetics with data from the dense Chinese networks of broadband seismic instruments, show a broader 660 km discontinuity (by about 30 to 70 km) and slower shear velocities above the MTZ than a global standard model iasp91 (Kennett and Engdahl, 1991). These features were interpreted with a mixture of different chemical properties which show delayed phase transformation, and effects of water above the flattened slab. Nonetheless, the SH-wave model has a structure similar to model TNA above the MTZ, which was derived for the

  17. A Modular and Affordable Time-Lapse Imaging and Incubation System Based on 3D-Printed Parts, a Smartphone, and Off-The-Shelf Electronics.

    Science.gov (United States)

    Hernández Vera, Rodrigo; Schwan, Emil; Fatsis-Kavalopoulos, Nikos; Kreuger, Johan

    2016-01-01

    Time-lapse imaging is a powerful tool for studying cellular dynamics and cell behavior over long periods of time to acquire detailed functional information. However, commercially available time-lapse imaging systems are expensive and this has limited a broader implementation of this technique in low-resource environments. Further, the availability of time-lapse imaging systems often present workflow bottlenecks in well-funded institutions. To address these limitations we have designed a modular and affordable time-lapse imaging and incubation system (ATLIS). The ATLIS enables the transformation of simple inverted microscopes into live cell imaging systems using custom-designed 3D-printed parts, a smartphone, and off-the-shelf electronic components. We demonstrate that the ATLIS provides stable environmental conditions to support normal cell behavior during live imaging experiments in both traditional and evaporation-sensitive microfluidic cell culture systems. Thus, the system presented here has the potential to increase the accessibility of time-lapse microscopy of living cells for the wider research community.

  18. Monitoring CO2 storage using seismic-interferometry ghost reflections

    NARCIS (Netherlands)

    Draganov, D.S.; Heller, H.K.J.; Ghose, R.

    2013-01-01

    Time-lapse seismic monitoring is a fundamental part in most monitoring programmes involving CO2 storage. Even though the seismic method has proven its applicability for monitoring, there are two major causes of uncertainty in the estimation of changes in the reservoir properties: non-repeatability

  19. Imaging subsurface migration of dissolved CO2 in a shallow aquifer using 3-D time-lapse electrical resistivity tomography

    DEFF Research Database (Denmark)

    Auken, Esben; Doetsch, Joseph; Fiandaca, Gianluca

    2014-01-01

    Contamination of groundwater by leaking CO2 is a potential risk of carbon sequestration. With the help of a field experiment in western Denmark, we investigate to what extent surface electrical resistivity tomography (ERT) can detect and image dissolved CO2 in a shallow aquifer. For this purpose...... of aeolian and glacial sands near the surface and marine sands below 10m depth. 3-D time-lapse ERT inversions clearly image the dissolved CO2 plume with decreased electrical resistivity values. We can image the geochemical changes induced by the dissolved CO2 until the end of the acquisition, 120days after......-intrusive surface electrical resistivity tomography. © 2013 Elsevier B.V....

  20. A time-lapse gravity survey of the Coso geothermal field, China Lake Naval Air Weapons Station, California

    Science.gov (United States)

    Phelps, Geoffrey; Cronkite-Ratcliff, Collin; Blake, Kelly

    2018-04-19

    We have conducted a gravity survey of the Coso geothermal field to continue the time-lapse gravity study of the area initiated in 1991. In this report, we outline a method of processing the gravity data that minimizes the random errors and instrument bias introduced into the data by the Scintrex CG-5 relative gravimeters that were used. After processing, the standard deviation of the data was estimated to be ±13 microGals. These data reveal that the negative gravity anomaly over the Coso geothermal field, centered on gravity station CER1, is continuing to increase in magnitude over time. Preliminary modeling indicates that water-table drawdown at the location of CER1 is between 65 and 326 meters over the last two decades. We note, however, that several assumptions on which the model results depend, such as constant elevation and free-water level over the study period, still require verification.

  1. Acquiring fluorescence time-lapse movies of budding yeast and analyzing single-cell dynamics using GRAFTS.

    Science.gov (United States)

    Zopf, Christopher J; Maheshri, Narendra

    2013-07-18

    Fluorescence time-lapse microscopy has become a powerful tool in the study of many biological processes at the single-cell level. In particular, movies depicting the temporal dependence of gene expression provide insight into the dynamics of its regulation; however, there are many technical challenges to obtaining and analyzing fluorescence movies of single cells. We describe here a simple protocol using a commercially available microfluidic culture device to generate such data, and a MATLAB-based, graphical user interface (GUI) -based software package to quantify the fluorescence images. The software segments and tracks cells, enables the user to visually curate errors in the data, and automatically assigns lineage and division times. The GUI further analyzes the time series to produce whole cell traces as well as their first and second time derivatives. While the software was designed for S. cerevisiae, its modularity and versatility should allow it to serve as a platform for studying other cell types with few modifications.

  2. Technical Note: Semi-automated effective width extraction from time-lapse RGB imagery of a remote, braided Greenlandic river

    Science.gov (United States)

    Gleason, C. J.; Smith, L. C.; Finnegan, D. C.; LeWinter, A. L.; Pitcher, L. H.; Chu, V. W.

    2015-06-01

    River systems in remote environments are often challenging to monitor and understand where traditional gauging apparatus are difficult to install or where safety concerns prohibit field measurements. In such cases, remote sensing, especially terrestrial time-lapse imaging platforms, offer a means to better understand these fluvial systems. One such environment is found at the proglacial Isortoq River in southwestern Greenland, a river with a constantly shifting floodplain and remote Arctic location that make gauging and in situ measurements all but impossible. In order to derive relevant hydraulic parameters for this river, two true color (RGB) cameras were installed in July 2011, and these cameras collected over 10 000 half hourly time-lapse images of the river by September of 2012. Existing approaches for extracting hydraulic parameters from RGB imagery require manual or supervised classification of images into water and non-water areas, a task that was impractical for the volume of data in this study. As such, automated image filters were developed that removed images with environmental obstacles (e.g., shadows, sun glint, snow) from the processing stream. Further image filtering was accomplished via a novel automated histogram similarity filtering process. This similarity filtering allowed successful (mean accuracy 79.6 %) supervised classification of filtered images from training data collected from just 10 % of those images. Effective width, a hydraulic parameter highly correlated with discharge in braided rivers, was extracted from these classified images, producing a hydrograph proxy for the Isortoq River between 2011 and 2012. This hydrograph proxy shows agreement with historic flooding observed in other parts of Greenland in July 2012 and offers promise that the imaging platform and processing methodology presented here will be useful for future monitoring studies of remote rivers.

  3. Technical Note: Semi-automated classification of time-lapse RGB imagery for a remote Greenlandic river

    Science.gov (United States)

    Gleason, C. J.; Smith, L. C.; Finnegan, D. C.; LeWinter, A. L.; Pitcher, L. H.; Chu, V. W.

    2015-01-01

    River systems in remote environments are often challenging to monitor and understand where traditional gauging apparatus are difficult to install or where safety concerns prohibit field measurements. In such cases, remote sensing, especially terrestrial time lapse imaging platforms, offer a means to better understand these fluvial systems. One such environment is found at the proglacial Isortoq River in southwest Greenland, a river with a constantly shifting floodplain and remote Arctic location that make gauging and in situ measurements all but impossible. In order to derive relevant hydraulic parameters for this river, two RGB cameras were installed in July of 2011, and these cameras collected over 10 000 half hourly time-lapse images of the river by September of 2012. Existing approaches for extracting hydraulic parameters from RGB imagery require manual or supervised classification of images into water and non-water areas, a task that was impractical for the volume of data in this study. As such, automated image filters were developed that removed images with environmental obstacles (e.g. shadows, sun glint, snow) from the processing stream. Further image filtering was accomplished via a novel automated histogram similarity filtering process. This similarity filtering allowed successful (mean accuracy 79.6%) supervised classification of filtered images from training data collected from just 10% of those images. Effective width, a hydraulic parameter highly correlated with discharge in braided rivers, was extracted from these classified images, producing a hydrograph proxy for the Isortoq River between 2011 and 2012. This hydrograph proxy shows agreement with historic flooding observed in other parts of Greenland in July 2012 and offers promise that the imaging platform and processing methodology presented here will be useful for future monitoring studies of remote rivers.

  4. Preliminary observations on polar body extrusion and pronuclear formation in human oocytes using time-lapse video cinematography.

    Science.gov (United States)

    Payne, D; Flaherty, S P; Barry, M F; Matthews, C D

    1997-03-01

    In this study, we have used time-lapse video cinematography to study fertilization in 50 human oocytes that had undergone intracytoplasmic sperm injection (ICSI). Time-lapse recording commenced shortly after ICSI and proceeded for 17-20 h. Oocytes were cultured in an environmental chamber which was maintained under standard culture conditions. Overall, 38 oocytes (76%) were fertilized normally, and the fertilization rate and embryo quality were not significantly different from 487 sibling oocytes cultured in a conventional incubator. Normal fertilization followed a defined course of events, although the timing of these events varied markedly between oocytes. In 35 of the 38 fertilized oocytes (92%), there were circular waves of granulation within the ooplasm which had a periodicity of 20-53 min. The sperm head decondensed during this granulation phase. The second polar body was then extruded, and this was followed by the central formation of the male pronucleus. The female pronucleus formed in the cytoplasm adjacent to the second polar body at the same time as, or slightly after, the male pronucleus, and was subsequently drawn towards the male pronucleus until the two abutted. Both pronuclei then increased in size, the nucleoli moved around within the pronuclei and some nucleoli coalesced. During pronuclear growth, the organelles contracted from the cortex towards the centre of the oocyte, leaving a clear cortical zone. The oocyte decreased in diameter from 112 to 106 microm (P cinematography is an excellent tool for studying fertilization and early embryo development, and have demonstrated that human fertilization comprises numerous complex dynamic events.

  5. In vivo time-lapse imaging of cell proliferation and differentiation in the optic tectum of Xenopus laevis tadpoles

    Science.gov (United States)

    Bestman, Jennifer E.; Lee-Osbourne, Jane; Cline, Hollis T.

    2012-01-01

    We analyzed the function of neural progenitors in the developing CNS of Xenopus laevis tadpoles using in vivo time-lapse confocal microscopy to collect images through the tectum at intervals of 2 to 24 hours over 3 days. Neural progenitor cells were labeled with fluorescent protein reporters based on expression of endogenous Sox2 transcription factor. With this construct, we identified Sox2-expressing cells as radial glia and as a component of the progenitor pool of cells in the developing tectum that gives rise to neurons and other radial glia. Lineage analysis of individual radial glia and their progeny demonstrated that less than 10% of radial glia undergo symmetric divisions resulting in two radial glia, while the majority of radial glia divide asymmetrically to generate neurons and radial glia. Time-lapse imaging revealed the direct differentiation of radial glia into neurons. Although radial glia may guide axons as they navigate to superficial tectum, we find no evidence that radial glia function as a scaffold for neuronal migration at early stages of tectal development. Over three days, the number of labeled cells increased 20%, as the fraction of radial glia dropped and the proportion of neuronal progeny increased to approximately 60% of the labeled cells. Tadpoles provided with short-term visual enhancement generated significantly more neurons, with a corresponding decrease in cell proliferation. Together these results demonstrate that radial glial cells are neural progenitors in the developing optic tectum and reveal that visual experience increases the proportion of neurons generated in an intact animal. PMID:22113462

  6. Time-lapse ERT and DTS for seasonal and short-term monitoring of an alpine river hyporheic zone

    Science.gov (United States)

    Boaga, Jacopo; Laura, Busato; Mariateresa, Perri; Giorgio, Cassiani

    2016-04-01

    The hyporheic zone (HZ) is the area located beneath and adjacent to rivers and streams, where the interactions between surface water and groundwater take place. This complex physical domain allows the transport of several substances from a stream to the unconfined aquifer below, and vice versa, thus playing a fundamental role in the river ecosystem. The importance of the hyporheic zone makes its characterization a goal shared by several disciplines, which range from applied geophysics to biogeochemistry, from hydraulics to ecology. The frontier field of HZ characterization stays in applied non-invasive methodologies as Electrical Resistivity Tomography - ERT - and Distributed Temperature Sensing - DTS. ERT is commonly applied in cross-well configuration or with a superficial electrodes deployment while DTS is used in hydro-geophysics in the last decade, revealing a wide applicability to the typical issues of this field of study. DTS for hydro-geophysics studies is based on Raman scattering and employs heat as tracer and uses a fiber-optic cable to acquire temperature values. We applied both techniques for an alpine river case studies located in Val di Sole, TN, Italy. The collected measurements allow high-resolution characterization of the hyporheic zone, overcoming the critical problem of invasive measurements under riverbeds. In this work, we present the preliminary results regarding the characterization of the hyporheic zone of the alpine river obtained combining ERT and DTS time-lapse measurements. The data collection benefits from an innovative instrumentation deployment, which consists of both an ERT multicore cable and a DTS fiber-optic located in two separated boreholes drilled 5m under the watercourse and perpendicular to it. In particular we present the first year monitoring results and a short time-lapse monitoring experiment conducted during summer 2015. The site and the results here described are part of the EU FP7 CLIMB (Climate Induced Changes on the

  7. OPTICAL FLOW APPLIED TO TIME-LAPSE IMAGE SERIES TO ESTIMATE GLACIER MOTION IN THE SOUTHERN PATAGONIA ICE FIELD

    Directory of Open Access Journals (Sweden)

    E. Lannutti

    2016-06-01

    Full Text Available In this work, we assessed the feasibility of using optical flow to obtain the motion estimation of a glacier. In general, former investigations used to detect glacier changes involve solutions that require repeated observations which are many times based on extensive field work. Taking into account glaciers are usually located in geographically complex and hard to access areas, deploying time-lapse imaging sensors, optical flow may provide an efficient solution at good spatial and temporal resolution to describe mass motion. Several studies in computer vision and image processing community have used this method to detect large displacements. Therefore, we carried out a test of the proposed Large Displacement Optical Flow method at the Viedma Glacier, located at South Patagonia Icefield, Argentina. We collected monoscopic terrestrial time-lapse imagery, acquired by a calibrated camera at every 24 hour from April 2014 until April 2015. A filter based on temporal correlation and RGB color discretization between the images was applied to minimize errors related to changes in lighting, shadows, clouds and snow. This selection allowed discarding images that do not follow a sequence of similarity. Our results show a flow field in the direction of the glacier movement with acceleration in the terminus. We analyzed the errors between image pairs, and the matching generally appears to be adequate, although some areas show random gross errors related to the presence of changes in lighting. The proposed technique allowed the determination of glacier motion during one year, providing accurate and reliable motion data for subsequent analysis.

  8. Site response, shallow shear-wave velocity, and wave propagation at the San Jose, California, dense seismic array

    Science.gov (United States)

    Hartzell, S.; Carver, D.; Williams, R.A.; Harmsen, S.; Zerva, A.

    2003-01-01

    Ground-motion records from a 52-element dense seismic array near San Jose, California, are analyzed to obtain site response, shallow shear-wave velocity, and plane-wave propagation characteristics. The array, located on the eastern side of the Santa Clara Valley south of the San Francisco Bay, is sited over the Evergreen basin, a 7-km-deep depression with Miocene and younger deposits. Site response values below 4 Hz are up to a factor of 2 greater when larger, regional records are included in the analysis, due to strong surface-wave development within the Santa Clara Valley. The pattern of site amplification is the same, however, with local or regional events. Site amplification increases away from the eastern edge of the Santa Clara Valley, reaching a maximum over the western edge of the Evergreen basin, where the pre-Cenozoic basement shallows rapidly. Amplification then decreases further to the west. This pattern may be caused by lower shallow shear-wave velocities and thicker Quaternary deposits further from the edge of the Santa Clara Valley and generation/trapping of surface waves above the shallowing basement of the western Evergreen basin. Shear-wave velocities from the inversion of site response spectra based on smaller, local earthquakes compare well with those obtained independently from our seismic reflection/refraction measurements. Velocities from the inversion of site spectra that include larger, regional records do not compare well with these measurements. A mix of local and regional events, however, is appropriate for determination of site response to be used in seismic hazard evaluation, since large damaging events would excite both body and surface waves with a wide range in ray parameters. Frequency-wavenumber, plane-wave analysis is used to determine the backazimuth and apparent velocity of coherent phases at the array. Conventional, high-resolution, and multiple signal characterization f-k power spectra and stacked slowness power spectra are

  9. Three-dimensional seismic velocity model of theWest Bohemia/Vogtland seismoactive region

    Czech Academy of Sciences Publication Activity Database

    Růžek, Bohuslav; Horálek, Josef

    2013-01-01

    Roč. 195, č. 2 (2013), s. 1251-1266 ISSN 0956-540X R&D Projects: GA ČR GAP210/12/2336; GA MŠk LM2010008 Institutional support: RVO:67985530 Keywords : controlled source seismology * body waves * seismic tomography * crustal structure Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.724, year: 2013

  10. Velocity structure and the role of fluids in the West Bohemia Seismic Zone

    Czech Academy of Sciences Publication Activity Database

    Alexandrakis, C.; Calò, M.; Bouchaala, F.; Vavryčuk, Václav

    2014-01-01

    Roč. 5, č. 2 (2014), s. 863-872 ISSN 1869-9510 R&D Projects: GA ČR(CZ) GAP210/12/1491 EU Projects: European Commission(XE) 230669 - AIM Institutional support: RVO:67985530 Keywords : seismic tomography * Bohemia/Vogtland seismoactive region * WEBNET Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.270, year: 2014

  11. Fighting for territories: time-lapse analysis of dental pulp and dental follicle stem cells in co-culture reveals specific migratory capabilities

    Directory of Open Access Journals (Sweden)

    C Schiraldi

    2012-11-01

    Full Text Available Stem cell migration is a critical step during the repair of damaged tissues. In order to achieve appropriate cell-based therapies for tooth and periodontal ligament repair it is necessary first to understand the dynamics of tissue-specific stem cell populations such as dental pulp stem cells (DPSC and dental follicle stem cells (DFSC. Using time-lapse imaging, we analysed migratory and proliferative capabilities of these two human stem cell lines in vitro. When cultured alone, both DPSC and DFSC exhibited low and irregular migration profiles. In co-cultures, DFSC, but not DPSC, spectacularly increased their migration activity and velocity. DFSC rapidly surrounded the DPSC, thus resembling the in vivo developmental process, where follicle cells encircle both dental epithelium and pulp. Cell morphology was dependent on the culture conditions (mono-culture or co-culture and changed over time. Regulatory genes involved in dental cell migration and differentiation such as TWIST1, MSX1, RUNX2, SFRP1 and ADAM28, were also evaluated in co-cultures. MSX1 up-regulation indicates that DPSC and DFSC retain their odontogenic potential. However, DPSC lose their capacity to differentiate into odontoblasts in the presence of DFSC, as suggested by RUNX2 up-regulation and TWIST1 down-regulation. In contrast, the unchanged levels of SFRP1 expression suggest that DFSC retain their potential to form periodontal tissues even in the presence of DPSC. These findings demonstrate that stem cells behave differently according to their environment, retain their genetic memory, and compete with each other to acquire the appropriate territory. Understanding the mechanisms involved in stem cell migration may lead to new therapeutic approaches for tooth repair.

  12. Seismicity and velocity structure of the Southern Chilean subduction zone (between 37° and 39°S) revealed by the TIPTEQ local seismic network

    Science.gov (United States)

    Haberland, C.; Rietbrock, A.; Lange, D.; Bataille, K.; Dahm, T.

    2006-12-01

    The largest earthquakes are being generated at convergent plate boundaries, where oceanic plates subduct beneath other tectonic plates. Understanding the factors leading to these earthquakes in the coupling zone of convergent margins and their interrelation with surface deformation are the main aims of the international and interdisciplinary research initiative TIPTEQ (From The Incoming Plate To megaThrust EarthQuake Processes). High resolution images of the seismogenic zone and the forearc structure form the base for identifying the processes involved. Within this project a large temporary seismological network was installed in southern Chile between November 2004 and October 2005, covering the forearc between 37° and 39°~S. In this region the Mw=9.5 1960 Chile earthquake, the worldwide largest instrumentally ever recorded earthquake, nucleated. The network consisted of up to 120 digitally recording and continuously running seismic stations equipped with short period sensors. The onshore network was complemented by 10 ocean bottom seismometers/hydrophones. In total we observed 544 local earthquakes (with local magnitudes between 1 and 5.2) and numerous regional and teleseismic events. A high-quality subset of 213 local earthquakes with 14.754 P and S onset times (occurring in the interseismic cycle) was used for a simultaneous inversion for the 1-D velocity model and precise earthquake locations. By relocating artificial shots we estimated the accuracy of the earthquake hypocenter to about 1~km horizontally and 500~m vertically. In a second step, locations and 1-D model were used for the simultaneous inversion for the 3-D velocity structure and hypocenters (tomography). The events are found in the crustal forearc, the downgoing plate, and at the interface between both plates. Crustal events along NW and NNW striking, deep-reaching faults reflect the interseismic transpressional deformation of the forearc crust due to the subduction of the Nazca plate. The

  13. Three-dimensional seismic velocity models, high-precision earthquake locations and their implications for seismic, tectonic and magmatic settings in the Coso Geothermal Field, California

    Science.gov (United States)

    Zhang, Q.; Lin, G.

    2012-12-01

    The Coso Geothermal Field (CGF) lies at the east of Sierra Nevada and is situated in tectonically active area with the presence of hot spring, rhyolite domes at the surface, strike-slip and normal faulting and frequent seismic activity. In this study, we present our comprehensive analysis of three-dimensional velocity structure, high-precision earthquake relocation and in situ Vp/Vs estimates. We select 1,893 master events among 177,000 events between 1981 and 2011 recorded by the Southern California Seismic Network stations. High-resolution three-dimensional (3-D) Vp and Vp/Vs models in Coso are inverted from the master events with 52,160 P- and 23,688 S-wave first arrivals by using the SIMUL2000 algorithm. The tomographic model reveals slightly high Vp and Vp/Vs in most regions of Coso near the surface compared to the layers at depth of 6 and 12 km, which is consistent with the fact that the Coso area is filled with diorite and minor basalt. The feature of low Vp, low Vs and low Vp/Vs between 6 and 12 km depths underneath the CGF can be related to the porous, gas-filled rock or volatile-rich magma. The low Vp, low Vs and low Vp/Vs structure from the surface to 3 km depth beneath the Indian Wells Valley is consistent with the existence of the 2 km deep sediment strata revealed by the borehole data. The resulting new 3-D velocity model is used to improve the absolute event location accuracy. We then apply waveform cross-correlation, similar event cluster analysis and differential time relocation methods to improve relative event location accuracy with the horizontal and vertical location uncertainties in tens of meters. The relocated seismicity indicates that the brittle-ductile transition depth is as shallow as 5 km underneath the CGF. We also estimate in situ near-source Vp/Vs ratio within each event cluster using differential times from cross-correlation to complement the Vp/Vs model from tomographic inversions, which will help to estimate the volume fraction of

  14. 3-D velocity structures, seismicity patterns, and their tectonic implications across the Andean Foreland of San Juan Argentina

    Science.gov (United States)

    Asmerom, Biniam Beyene

    Three-dimensional velocity structures and seismicity patterns have been studied across the Andean Foreland of San Juan Argentina using data acquired by PANDA deployment. Distinct velocity variations are revealed between Precordillera in the west and Pie de Palo in the east. The low velocity anomaly beneath Precordillera is associated with the presence of thick sedimentary rocks and thick sediment cover of Matagusanos valley. Similarly, the high velocity anomaly east of Eastern Precordillera is correlated with the presence of basement rocks. These anomalies are observed from the station corrections of Joint Hypocentral Determination (JHD) analysis. A northeast trending west dipping high velocity anomaly is imaged beneath the southern half of Pie de Palo. This anomaly represents a Grenvillian suture zone formed when Pie de Palo collided with the Precordillera. Relocated seismicity using 3-D Vp and Vs models obtained in this study revealed crustal scale buried faults beneath the Eastern Precordillera and Sierra Pie de Palo. The fault defined by the seismicity extend down to a depth of ˜ 40 km and ~35 km beneath Precordillera and Pie de Palo, respectively, defining the lower bound of the brittle to ductile transition of the crust. These results confirm that present day active crustal thickening involves the entire crust in the tectonic process and results in thick-skinned deformation beneath both the Eastern Precordillera and Pie de Palo. Based on the seismicity pattern, geomorphology, and velocity structures, Sierra Pie de Palo, a basement uplift block, can be divided into two separate semi-blocks separated by a northeast trending fracture zone. The northern block is characterized by a well-defined west dipping fault and low Vp/Vs ratio particularly at a depth of 12 to 16 km, while the southern block shows a poorly-defined east dipping fault with high Vp/Vs ratio at a depth of 20 to 26 km. Spatial distribution of the well-relocated crustal earthquakes along these

  15. Seismic Travel Time Tomography in Modeling Low Velocity Anomalies between the Boreholes

    Science.gov (United States)

    Octova, A.; Sule, R.

    2018-04-01

    Travel time cross-hole seismic tomography is applied to describing the structure of the subsurface. The sources are placed at one borehole and some receivers are placed in the others. First arrival travel time data that received by each receiver is used as the input data in seismic tomography method. This research is devided into three steps. The first step is reconstructing the synthetic model based on field parameters. Field parameters are divided into 24 receivers and 45 receivers. The second step is applying inversion process for the field data that consists of five pairs bore holes. The last step is testing quality of tomogram with resolution test. Data processing using FAST software produces an explicit shape and resemble the initial model reconstruction of synthetic model with 45 receivers. The tomography processing in field data indicates cavities in several place between the bore holes. Cavities are identified on BH2A-BH1, BH4A-BH2A and BH4A-BH5 with elongated and rounded structure. In resolution tests using a checker-board, anomalies still can be identified up to 2 meter x 2 meter size. Travel time cross-hole seismic tomography analysis proves this mothod is very good to describing subsurface structure and boundary layer. Size and anomalies position can be recognized and interpreted easily.

  16. Seismic microzonation and velocity models of El Ejido area (SE Spain) from the diffuse-field H/V method

    Science.gov (United States)

    García-Jerez, Antonio; Seivane, Helena; Navarro, Manuel; Piña-Flores, José; Luzón, Francisco; Vidal, Francisco; Posadas, Antonio M.; Aranda, Carolina

    2016-04-01

    El Ejido town is located in the Campo de Dalías coastal plain (Almería province, SE Spain), emplaced in one of the most seismically active regions of Spain. The municipality has 84000 inhabitants and presented a high growth rate during the last twenty years. The most recent intense seismic activity occurred close to this town was in 1993 and 1994, with events of Mb = 4.9 and Mb = 5.0, respectively. To provide a basis for site-specific hazard analysis, we first carried out a seismic microzonation of this town in terms of predominant periods and geotechnical properties. The predominant periods map was obtained from ambient noise observations on a grid of 250 x 250 m in the main urban area, and sparser measurements on the outskirts. These broad-band records, of about 20 minutes long each, were analyzed by using the horizontal-to-vertical spectral ratio technique (H/V). Dispersion curves obtained from two array measurements of ambient noise and borehole data provided additional geophysical information. All the surveyed points in the town were found to have relatively long predominant periods ranging from 0.8 to 2.3 s and growing towards the SE. Secondary high-frequency (> 2Hz) peaks were found at about the 10% of the points only. On the other hand, Vs30 values of 550 - 650 m/s were estimated from the array records, corresponding to cemented sediments and medium-hard rocks. The local S-wave velocity structure has been inverted from the H/V curves for a subset of the measurement sites. We used an innovative full-wavefield method based on the diffuse-wavefield approximation (Sánchez-Sesma et al., 2011) combined with the simulated annealing algorithm. Shallow seismic velocities and deep boreholes data were used as constraints. The results show that the low-frequency resonances are related with the impedance contrast between several hundred meters of medium-hard sedimentary rocks (marls and calcarenites) with the stiffer basement of the basin, which dips to the SE. These

  17. Time-lapse gravity and levelling in the sinkhole-endangered urban area of Bad Frankenhausen, Germany

    Science.gov (United States)

    Kobe, Martin; Gabriel, Gerald; Weise, Adelheid; Krawczyk, Charlotte; Vogel, Detlef

    2017-04-01

    Sinkholes, resulting from subrosion in the subsurface, can reach diameters of several hundred meters and thus pose a severe hazard for infrastructure and inhabitants in urban areas. Subrosion is the leaching of readily-soluble rocks, such as rock salt, gypsum, anhydrite and limestone by ground or meteoric water and leads to mass transport and relocation. Two scenarios of sinkhole evolution are conceivable: First, the surface subsides continuously in order to compensate for the mass loss. Second, the mass relocation leads to development of subsurface cavities. If they reach a critical size and the cover layers are not supported anymore, the surface collapses abruptly. To improve the understanding of subrosion processes and the related surface deformation a case study is conducted in Bad Frankenhausen, Germany, where subrosion leaches the Zechstein evaporates of the Permian. One part of the study is to analyse the spatiotemporal development of sinkholes by applying time-lapse observations. Therefore, we established a monitoring network consisting of 15 gravity and additional levelling points covering the main sinkhole areas in the city centre. In March 2014, the baseline survey was carried out. Since then, quarterly measurement campaigns are performed. In each campaign four different gravity meters are used to collect a statistical significant amount of data and to control the plausibility of our data. The gravity measurements are complemented by levelling surveys. The rectification of the time-lapse gravity data comprises the correction for jumps and systematic errors, as well as for well calculable influences, such as earth tides and air pressure changes. Furthermore, special interest was applied to seasonal changes of hydrological parameters such as soil moisture or groundwater level. We found the hydrological influence to be in the single digit up to the lower two-digit µGal range, depending on the season and the station. The standard deviations of the adjusted

  18. Seismic structure beneath the Gulf of California: a contribution from group velocity measurements

    Science.gov (United States)

    Di Luccio, F.; Persaud, P.; Clayton, R. W.

    2014-12-01

    Rayleigh wave group velocity dispersion measurements from local and regional earthquakes are used to interpret the lithospheric structure in the Gulf of California region. We compute group velocity maps for Rayleigh waves from 10 to 150 s using earthquakes recorded by broad-band stations of the Network of Autonomously Recording Seismographs in Baja California and Mexico mainland, UNM in Mexico, BOR, DPP and GOR in southern California and TUC in Arizona. The study area is gridded in 120 longitude cells by 180 latitude cells, with an equal spacing of 10 × 10 km. Assuming that each gridpoint is laterally homogeneous, for each period the tomographic maps are inverted to produce a 3-D lithospheric shear wave velocity model for the region. Near the Gulf of California rift axis, we found three prominent low shear wave velocity regions, which are associated with mantle upwelling near the Cerro Prieto volcanic field, the Ballenas Transform Fault and the East Pacific Rise. Upwelling of the mantle at lithospheric and asthenospheric depths characterizes most of the Gulf. This more detailed finding is new when compared to previous surface wave studies in the region. A low-velocity zone in northcentral Baja at ˜28ºN which extends east-south-eastwards is interpreted as an asthenospheric window. In addition, we also identify a well-defined high-velocity zone in the upper mantle beneath central-western Baja California, which correlates with the previously interpreted location of the stalled Guadalupe and Magdalena microplates. We interpret locations of the fossil slab and slab window in light of the distribution of unique post-subduction volcanic rocks in the Gulf of California and Baja California. We also observe a high-velocity anomaly at 50-km depth extending down to ˜130 km near the southwestern Baja coastline and beneath Baja, which may represent another remnant of the Farallon slab.

  19. An effective assay for high cellular resolution time-lapse imaging of sensory placode formation and morphogenesis

    Directory of Open Access Journals (Sweden)

    Das Raman M

    2011-05-01

    Full Text Available Abstract Background The vertebrate peripheral nervous system contains sensory neurons that arise from ectodermal placodes. Placodal cells ingress to move inside the head to form sensory neurons of the cranial ganglia. To date, however, the process of placodal cell ingression and underlying cellular behavior are poorly understood as studies have relied upon static analyses on fixed tissues. Visualizing placodal cell behavior requires an ability to distinguish the surface ectoderm from the underlying mesenchyme. This necessitates high resolution imaging along the z-plane which is difficult to accomplish in whole embryos. To address this issue, we have developed an imaging system using cranial slices that allows direct visualization of placode formation. Results We demonstrate an effective imaging assay for capturing placode development at single cell resolution using chick embryonic tissue ex vivo. This provides the first time-lapse imaging of mitoses in the trigeminal placodal ectoderm, ingression, and intercellular contacts of placodal cells. Cell divisions with varied orientations were found in the placodal ectoderm all along the apical-basal axis. Placodal cells initially have short cytoplasmic processes during ingression as young neurons and mature over time to elaborate long axonal processes in the mesenchyme. Interestingly, the time-lapse imaging data reveal that these delaminating placodal neurons begin ingression early on from within the ectoderm, where they start to move and continue on to exit as individual or strings of neurons through common openings on the basal side of the epithelium. Furthermore, dynamic intercellular contacts are abundant among the delaminating placodal neurons, between these and the already delaminated cells, as well as among cells in the forming ganglion. Conclusions This new imaging assay provides a powerful method to analyze directly development of placode-derived sensory neurons and subsequent ganglia

  20. Field measurement of erosion rates: time-lapse monitoring of rapid stone flaking at Howden Minster, UK

    Science.gov (United States)

    Doehne, E.; Pinchin, S.

    2012-04-01

    The use of a solar-powered, field time-lapse camera and environmental monitoring system enabled measurements of the pattern and rate of loss of stone from the surface of Howden Minster, an abandoned monastery in Yorkshire dating to 1380 AD. Acquiring a photograph every 1-3 hours allowed the stone damage to be correlated with local environmental conditions. Image comparison techniques borrowed from observational astronomy, such as blink comparison, were used to determine what elements had changed from image to image. Results indicate that loss is episodic rather than continuous and in several cases is related to specific environmental conditions, such as condensation/dew formation or high winds. Damage was found also to be synchronous, with surface change (flaking, granular disintegration, and loss of flakes) occurring at the same time on different stone blocks. Crystallization pressure from magnesium sulfate phase transitions appear to be the main cause of the loss of stone surfaces. Significant variation in surface loss rates was observed and appears to be related to variations in salt concentration. An examination of stone texture by ESEM/EDS revealed signification variations and suggests that salt concentrations are controlled in part by stone micromorphology. Quantitative data on rates of surface loss are not available from most monuments. Time-lapse methods permit the relatively inexpensive acquisition of this type of data, which is needed to aid conservation decision-making and the evaluation of interventions. Such tools should also prove useful to geomorphologists studying honeycomb weathering, the moving rocks on Death Valley's Racetrack Playa, and other phenomena that are otherwise difficult to study. Context: The rapid deterioration of magnesian limestone structures in the north of England has been a serious problem for more than one hundred years. While air quality in England has improved during this period, the rate of stone loss in these carved stone

  1. Blind test of methods for obtaining 2-D near-surface seismic velocity models from first-arrival traveltimes

    Science.gov (United States)

    Zelt, Colin A.; Haines, Seth; Powers, Michael H.; Sheehan, Jacob; Rohdewald, Siegfried; Link, Curtis; Hayashi, Koichi; Zhao, Don; Zhou, Hua-wei; Burton, Bethany L.; Petersen, Uni K.; Bonal, Nedra D.; Doll, William E.

    2013-01-01

    Seismic refraction methods are used in environmental and engineering studies to image the shallow subsurface. We present a blind test of inversion and tomographic refraction analysis methods using a synthetic first-arrival-time dataset that was made available to the community in 2010. The data are realistic in terms of the near-surface velocity model, shot-receiver geometry and the data's frequency and added noise. Fourteen estimated models were determined by ten participants using eight different inversion algorithms, with the true model unknown to the participants until it was revealed at a session at the 2011 SAGEEP meeting. The estimated models are generally consistent in terms of their large-scale features, demonstrating the robustness of refraction data inversion in general, and the eight inversion algorithms in particular. When compared to the true model, all of the estimated models contain a smooth expression of its two main features: a large offset in the bedrock and the top of a steeply dipping low-velocity fault zone. The estimated models do not contain a subtle low-velocity zone and other fine-scale features, in accord with conventional wisdom. Together, the results support confidence in the reliability and robustness of modern refraction inversion and tomographic methods.

  2. Stress-dependent elastic properties of shales—laboratory experiments at seismic and ultrasonic frequencies

    Science.gov (United States)

    Szewczyk, Dawid; Bauer, Andreas; Holt, Rune M.

    2018-01-01

    Knowledge about the stress sensitivity of elastic properties and velocities of shales is important for the interpretation of seismic time-lapse data taken as part of reservoir and caprock surveillance of both unconventional and conventional oil and gas fields (e.g. during 4-D monitoring of CO2 storage). Rock physics models are often developed based on laboratory measurements at ultrasonic frequencies. However, as shown previously, shales exhibit large seismic dispersion, and it is possible that stress sensitivities of velocities are also frequency dependent. In this work, we report on a series of seismic and ultrasonic laboratory tests in which the stress sensitivity of elastic properties of Mancos shale and Pierre shale I were investigated. The shales were tested at different water saturations. Dynamic rock engineering parameters and elastic wave velocities were examined on core plugs exposed to isotropic loading. Experiments were carried out in an apparatus allowing for static-compaction and dynamic measurements at seismic and ultrasonic frequencies within single test. For both shale types, we present and discuss experimental results that demonstrate dispersion and stress sensitivity of the rock stiffness, as well as P- and S-wave velocities, and stiffness anisotropy. Our experimental results show that the stress-sensitivity of shales is different at seismic and ultrasonic frequencies, which can be linked with simultaneously occurring changes in the dispersion with applied stress. Measured stress sensitivity of elastic properties for relatively dry samples was higher at seismic frequencies however, the increasing saturation of shales decreases the difference between seismic and ultrasonic stress-sensitivities, and for moist samples stress-sensitivity is higher at ultrasonic frequencies. Simultaneously, the increased saturation highly increases the dispersion in shales. We have also found that the stress-sensitivity is highly anisotropic in both shales and that in

  3. Seismic velocity structure and microearthquake source properties at The Geysers, California, geothermal area

    Energy Technology Data Exchange (ETDEWEB)

    O' Connell, D.R.

    1986-12-01

    The method of progressive hypocenter-velocity inversion has been extended to incorporate S-wave arrival time data and to estimate S-wave velocities in addition to P-wave velocities. S-wave data to progressive inversion does not completely eliminate hypocenter-velocity tradeoffs, but they are substantially reduced. Results of a P and S-wave progressive hypocenter-velocity inversion at The Geysers show that the top of the steam reservoir is clearly defined by a large decrease of V/sub p//V/sub s/ at the condensation zone-production zone contact. The depth interval of maximum steam production coincides with minimum observed V/sub p//V/sub s/, and V/sub p//V/sub s/ increses below the shallow primary production zone suggesting that reservoir rock becomes more fluid saturated. The moment tensor inversion method was applied to three microearthquakes at The Geysers. Estimated principal stress orientations were comparable to those estimated using P-wave firstmotions as constraints. Well constrained principal stress orientations were obtained for one event for which the 17 P-first motions could not distinguish between normal-slip and strike-slip mechanisms. The moment tensor estimates of principal stress orientations were obtained using far fewer stations than required for first-motion focal mechanism solutions. The three focal mechanisms obtained here support the hypothesis that focal mechanisms are a function of depth at The Geysers. Progressive inversion as developed here and the moment tensor inversion method provide a complete approach for determining earthquake locations, P and S-wave velocity structure, and earthquake source mechanisms.

  4. Remote estimation of the hydraulic properties of a sand using full-waveform integrated hydrogeophysical inversion of time-lapse, off-ground GPR data

    NARCIS (Netherlands)

    Lambot, S.; Slob, E.; Rhebergen, J.B.; Lopera, O.; Jadoon, K.Z.; Vereecken, H.

    2009-01-01

    We used integrated hydrogeophysical inversion of time-lapse, proximal ground penetrating radar (GPR) data to remotely infer the unsaturated soil hydraulic properties of a laboratory sand during an infiltration event. The inversion procedure involved full-waveform modeling of the radar signal and

  5. Monitoring channel head erosion processes in response to an artificially induced abrupt base level change using time-lapse photography 2301

    Science.gov (United States)

    Headcut and channel extension in response to an abrupt base level change in 2004 of approximately 1m was studied in a 1.29 ha semiarid headwater drainage on the Walnut Gulch Experimental Watershed (WGEW) in southeastern Arizona, USA. Field observations and time-lapse photography were coupled with hy...

  6. Diferentes modelos de video Time-Lapse y su aplicación en las clínicas de reproducción asistida

    OpenAIRE

    Fanjul González, Paula

    2013-01-01

    TFM del Máster de Biología y Tecnología de la Reproducción sobre los distintos modelos de video Time-Lapse que se pueden utilizar para la valoración embrionaria en una clínica de reproducción asistida

  7. Time-lapse analysis of methane quantity in Mary Lee group of coal seams using filter-based multiple-point geostatistical simulation

    Science.gov (United States)

    Karacan, C. Özgen; Olea, Ricardo A.

    2013-01-01

    Coal seam degasification and its success are important for controlling methane, and thus for the health and safety of coal miners. During the course of degasification, properties of coal seams change. Thus, the changes in coal reservoir conditions and in-place gas content as well as methane emission potential into mines should be evaluated by examining time-dependent changes and the presence of major heterogeneities and geological discontinuities in the field. In this work, time-lapsed reservoir and fluid storage properties of the New Castle coal seam, Mary Lee/Blue Creek seam, and Jagger seam of Black Warrior Basin, Alabama, were determined from gas and water production history matching and production forecasting of vertical degasification wellbores. These properties were combined with isotherm and other important data to compute gas-in-place (GIP) and its change with time at borehole locations. Time-lapsed training images (TIs) of GIP and GIP difference corresponding to each coal and date were generated by using these point-wise data and Voronoi decomposition on the TI grid, which included faults as discontinuities for expansion of Voronoi regions. Filter-based multiple-point geostatistical simulations, which were preferred in this study due to anisotropies and discontinuities in the area, were used to predict time-lapsed GIP distributions within the study area. Performed simulations were used for mapping spatial time-lapsed methane quantities as well as their uncertainties within the study area.

  8. Hillslope characterization in terms of geophysical units based on the joint interpretation of electrical resistivity and seismic velocity data

    Science.gov (United States)

    Feskova, Tatiana; Dietrich, Peter

    2015-04-01

    Hydrological conditions in a catchment depend on many factors such as climatic, geological, geomorphological, biological and human, which interact with each other and influence water balance in a catchment. This interaction leads to the subordination in the landscape structure, namely the weak elements subordinate to the powerful elements. Thereby, geological and geomorphological factors play an essential role in catchment development and organization. A hillslope consequently can be allocated to one class of the representative units because the important flow processes run at the hillslope. Moreover, a hillslope can be subdivided into stratigraphic subsurface units and significant hillslope areas based on the lithological change of contrasting interfaces. The knowledge of subsurface structures is necessary to understand and predicate complex hydrological processes in a catchment. Geophysical techniques provide a good opportunity to explore the subsurface. A complete geophysical investigation of subsurface in a catchment with difficult environmental conditions never will be achieved because of large time effort in the field, equipment logistic, and ambiguity in the data interpretation. The case study demonstrates how a catchment can be investigated using geophysical methods in an effective manner in terms of characterization of representative units with respect to a functional role in the catchment. This case study aims to develop combined resistivity and seismic velocity hillslope subsurface models for the distinction of representative functional units. In order to identify the contrasting interfaces of the hillslope, to localize significant hillslope areas, and to address the ambiguity in the geophysical data interpretation, the case study combined resistivity surveys (vertical electrical soundings and electrical resistivity tomography) with refraction seismic method, and conducted these measurements at one single profile along the hillslope transect and

  9. Scattering images from autocorrelation functions of P-wave seismic velocity images: the case of Tenerife Island (Canary Islands, Spain)

    Science.gov (United States)

    García-Yeguas, A.; Sánchez-Alzola, A.; De Siena, L.; Prudencio, J.; Díaz-Moreno, A.; Ibáñez, J. M.

    2018-03-01

    We present a P-wave scattering image of the volcanic structures under Tenerife Island using the autocorrelation functions of P-wave vertical velocity fluctuations. We have applied a cluster analysis to total quality factor attenuation ( {Q}_t^{-1} ) and scattering quality factor attenuation ( {Q}_{PSc}^{-1} ) images to interpret the structures in terms of intrinsic and scattering attenuation variations on a 2D plane, corresponding to a depth of 2000 m, and check the robustness of the scattering imaging. The results show that scattering patterns are similar to total attenuation patterns in the south of the island. There are two main areas where patterns differ: at Cañadas-Teide-Pico Viejo Complex, high total attenuation and average-to-low scattering values are observed. We interpret the difference as induced by intrinsic attenuation. In the Santiago Ridge Zone (SRZ) region, high scattering values correspond to average total attenuation. In our interpretation, the anomaly is induced by an extended scatterer, geometrically related to the surficial traces of Garachico and El Chinyero historical eruptions and the area of highest seismic activity during the 2004-2008 seismic crises.

  10. The Relationship between Cell Number, Division Behavior and Developmental Potential of Cleavage Stage Human Embryos: A Time-Lapse Study.

    Directory of Open Access Journals (Sweden)

    Xiangyi Kong

    Full Text Available Day 3 cleavage embryo transfer is routine in many assisted reproductive technology centers today. Embryos are usually selected according to cell number, cell symmetry and fragmentation for transfer. Many studies have showed the relationship between cell number and embryo developmental potential. However, there is limited understanding of embryo division behavior and their association with embryo cell number and developmental potential. A retrospective and observational study was conducted to investigate how different division behaviors affect cell number and developmental potential of day 3 embryos by time-lapse imaging. Based on cell number at day 3, the embryos (from 104 IVF/intracytoplasmic sperm injection (ICSI treatment cycles, n = 799 were classified as follows: less than 5 cells (10C; n = 42. Division behavior, morphokinetic parameters and blastocyst formation rate were analyzed in 5 groups of day 3 embryos with different cell numbers. In 10C embryos increased compared to 7-8C embryos (45.8%, 33.3% vs. 11.1%, respectively. In ≥5C embryos, FR and DC significantly reduced developmental potential, whereas 10C. In NB embryos, the cell cycle elongation or shortening was the main cause for abnormally low or high cell number, respectively. After excluding embryos with abnormal division behaviors, the developmental potential, implantation rate and live birth rate of day 3 embryos increased with cell number.

  11. The sexual phase of the diatom Pseudo-nitzschia multistriata: cytological and time-lapse cinematography characterization.

    Science.gov (United States)

    Scalco, Eleonora; Amato, Alberto; Ferrante, Maria Immacolata; Montresor, Marina

    2016-11-01

    Pseudo-nitzschia is a thoroughly studied pennate diatom genus for ecological and biological reasons. Many species in this genus, including Pseudo-nitzschia multistriata, can produce domoic acid, a toxin responsible for amnesic shellfish poisoning. Physiological, phylogenetic and biological features of P. multistriata were studied extensively in the past. Life cycle stages, including the sexual phase, fundamental in diatoms to restore the maximum cell size and avoid miniaturization to death, have been well described for this species. P. multistriata is heterothallic; sexual reproduction is induced when strains of opposite mating type are mixed, and proceeds with cells producing two functionally anisogamous gametes each; however, detailed cytological information for this process is missing. By means of confocal laser scanning microscopy and nuclear staining, we followed the nuclear fate during meiosis, and using time-lapse cinematography, we timed every step of the sexual reproduction process from mate pairing to initial cell hatching. The present paper depicts cytological aspects during gametogenesis in P. multistriata, shedding light on the chloroplast behaviour during sexual reproduction, finely describing the timing of the sexual phases and providing reference data for further studies on the molecular control of this fundamental process.

  12. Comparative effects of ionizing radiation on cycle time and mitotic duration. A time-lapse cinematography study

    International Nuclear Information System (INIS)

    D'Hooghe, M.C.; Hemon, D.; Valleron, A.J.; Malaise, E.P.

    1980-01-01

    The effects of 60 Co γ rays on the length of the intermitotic period, the duration of mitosis, and the division probability of EMT6 cells have been studied in vitro using time-lapse cinematography. Irradiation increases the duration of the mitosis and of the cycle in comparable proportions: both parameters are practically doubled by a dose of 10 Gy. When daughters of irradiated cells die, the mitotic delay and lengthening of mitosis of their mother cells are longer than average. Mitotic delay and lengthening of mitosis depend on the age of cells at the moment of irradiation. The mitotic delay increases progressively when cells are irradiated during the first 8 h of their cycle (i.e., before the transition point), whereas mitosis is slightly prolonged. On the other hand, when the cells are irradiated after this transition point the mitotic delay decreases markedly, whereas the lengthening of mitosis increases sharply. These results tend to indicate that two different mechanisms are responsible for mitotic delay and prolongation of mitosis observed after irradiation

  13. Random walk behavior of migrating cortical interneurons in the marginal zone: time-lapse analysis in flat-mount cortex.

    Science.gov (United States)

    Tanaka, Daisuke H; Yanagida, Mitsutoshi; Zhu, Yan; Mikami, Sakae; Nagasawa, Takashi; Miyazaki, Jun-ichi; Yanagawa, Yuchio; Obata, Kunihiko; Murakami, Fujio

    2009-02-04

    Migrating neurons are thought to travel from their origin near the ventricle to distant territories along stereotypical pathways by detecting environmental cues in the extracellular milieu. Here, we report a novel mode of neuronal migration that challenges this view. We performed long-term, time-lapse imaging of medial ganglionic eminence (MGE)-derived cortical interneurons tangentially migrating in the marginal zone (MZ) in flat-mount cortices. We find that they exhibit a diverse range of behaviors in terms of the rate and direction of migration. Curiously, a predominant population of these neurons repeatedly changes its direction of migration in an unpredictable manner. Trajectories of migration vary from one neuron to another. The migration of individual cells lasts for long periods, sometimes up to 2 d. Theoretical analyses reveal that these behaviors can be modeled by a random walk. Furthermore, MZ cells migrate from the cortical subventricular zone to the cortical plate, transiently accumulating in the MZ. These results suggest that MGE-derived cortical interneurons, once arriving at the MZ, are released from regulation by guidance cues and initiate random walk movement, which potentially contributes to their dispersion throughout the cortex.

  14. Fusion of Time-Lapse Gravity Survey and Hydraulic Tomography for Estimating Spatially Varying Hydraulic Conductivity and Specific Yield Fields

    Science.gov (United States)

    Tsai, Jui-Pin; Yeh, Tian-Chyi Jim; Cheng, Ching-Chung; Zha, Yuanyuan; Chang, Liang-Cheng; Hwang, Cheinway; Wang, Yu-Li; Hao, Yonghong

    2017-10-01

    Hydraulic conductivity >(K>) and specific yield (Sy) are important aquifer parameters, pertinent to groundwater resources management and protection. These parameters are commonly estimated through a traditional cross-well pumping test. Employing the traditional approach to obtain detailed spatial distributions of the parameters over a large area is generally formidable. For this reason, this study proposes a stochastic method that integrates hydraulic head and time-lapse gravity based on hydraulic tomography (HT) to efficiently derive the spatial distribution of K and Sy over a large area. This method is demonstrated using several synthetic experiments. Results of these experiments show that the K and Sy fields estimated by joint inversion of the gravity and head data set from sequential injection tests in unconfined aquifers are superior to those from the HT based on head data alone. We attribute this advantage to the mass constraint imposed on HT by gravity measurements. Besides, we find that gravity measurement can detect the change of aquifer's groundwater storage at kilometer scale, as such they can extend HT's effectiveness over greater volumes of the aquifer. Furthermore, we find that the accuracy of the estimated fields is improved as the number of the gravity stations is increased. The gravity station's location, however, has minor effects on the estimates if its effective gravity integration radius covers the well field.

  15. Cinemechanometry (CMM): A method to determine the forces that drive morphogenetic movements from time-lapse images.

    Science.gov (United States)

    Cranston, P Graham; Veldhuis, Jim H; Narasimhan, Sriram; Brodland, G Wayne

    2010-09-01

    Although cell-level mechanical forces are crucial to tissue self-organization in contexts ranging from embryo development to cancer metastases to regenerative engineering, the absence of methods to map them over time has been a major obstacle to new understanding. Here, we present a technique for constructing detailed, dynamic maps of the forces driving morphogenetic events from time-lapse images. Forces in the cell are considered to be separable into unknown active driving forces and known passive forces, where actomyosin systems and microtubules contribute primarily to the first group and intermediate filaments and cytoplasm to the latter. A finite-element procedure is used to estimate the field of forces that must be applied to the passive components to produce their observed incremental deformations. This field is assumed to be generated by active forces resolved along user-defined line segments whose location, often along cell edges, is informed by the underlying biology. The magnitudes and signs of these forces are determined by a mathematical inverse method. The efficacy of the approach is demonstrated using noisy synthetic data from a cross section of a generic invagination and from a planar aggregate that involves two cell types, edge forces that vary with time and a neighbor change.

  16. Formation and spreading of TDP-43 aggregates in cultured neuronal and glial cells demonstrated by time-lapse imaging.

    Directory of Open Access Journals (Sweden)

    Tomohiro Ishii

    Full Text Available TAR DNA-binding protein 43 (TDP-43 is a main constituent of cytoplasmic aggregates in neuronal and glial cells in cases of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. We have previously demonstrated that adenovirus-transduced artificial TDP-43 cytoplasmic aggregates formation is enhanced by proteasome inhibition in vitro and in vivo. However, the relationship between cytoplasmic aggregate formation and cell death remains unclear. In the present study, rat neural stem cell lines stably transfected with EGFP- or Sirius-expression vectors under the control of tubulin beta III, glial fibrillary acidic protein, or 2',3'-cyclic nucleotide 3'-phosphodiesterase promoter were differentiated into neurons, astrocytes, and oligodendrocytes, respectively, in the presence of retinoic acid. The differentiated cells were then transduced with adenoviruses expressing DsRed-tagged human wild type and C-terminal fragment TDP-43 under the condition of proteasome inhibition. Time-lapse imaging analyses revealed growing cytoplasmic aggregates in the transduced neuronal and glial cells, followed by collapse of the cell. The aggregates remained insoluble in culture media, consisted of sarkosyl-insoluble granular materials, and contained phosphorylated TDP-43. Moreover, the released aggregates were incorporated into neighboring neuronal cells, suggesting cell-to-cell spreading. The present study provides a novel tool for analyzing the detailed molecular mechanisms of TDP-43 proteinopathy in vitro.

  17. Formation and spreading of TDP-43 aggregates in cultured neuronal and glial cells demonstrated by time-lapse imaging.

    Science.gov (United States)

    Ishii, Tomohiro; Kawakami, Emiko; Endo, Kentaro; Misawa, Hidemi; Watabe, Kazuhiko

    2017-01-01

    TAR DNA-binding protein 43 (TDP-43) is a main constituent of cytoplasmic aggregates in neuronal and glial cells in cases of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. We have previously demonstrated that adenovirus-transduced artificial TDP-43 cytoplasmic aggregates formation is enhanced by proteasome inhibition in vitro and in vivo. However, the relationship between cytoplasmic aggregate formation and cell death remains unclear. In the present study, rat neural stem cell lines stably transfected with EGFP- or Sirius-expression vectors under the control of tubulin beta III, glial fibrillary acidic protein, or 2',3'-cyclic nucleotide 3'-phosphodiesterase promoter were differentiated into neurons, astrocytes, and oligodendrocytes, respectively, in the presence of retinoic acid. The differentiated cells were then transduced with adenoviruses expressing DsRed-tagged human wild type and C-terminal fragment TDP-43 under the condition of proteasome inhibition. Time-lapse imaging analyses revealed growing cytoplasmic aggregates in the transduced neuronal and glial cells, followed by collapse of the cell. The aggregates remained insoluble in culture media, consisted of sarkosyl-insoluble granular materials, and contained phosphorylated TDP-43. Moreover, the released aggregates were incorporated into neighboring neuronal cells, suggesting cell-to-cell spreading. The present study provides a novel tool for analyzing the detailed molecular mechanisms of TDP-43 proteinopathy in vitro.

  18. Through the Looking Glass: Time-lapse Microscopy and Longitudinal Tracking of Single Cells to Study Anti-cancer Therapeutics.

    Science.gov (United States)

    Burke, Russell T; Orth, James D

    2016-05-14

    The response of single cells to anti-cancer drugs contributes significantly in determining the population response, and therefore is a major contributing factor in the overall outcome. Immunoblotting, flow cytometry and fixed cell experiments are often used to study how cells respond to anti-cancer drugs. These methods are important, but they have several shortcomings. Variability in drug responses between cancer and normal cells, and between cells of different cancer origin, and transient and rare responses are difficult to understand using population averaging assays and without being able to directly track and analyze them longitudinally. The microscope is particularly well suited to image live cells. Advancements in technology enable us to routinely image cells at a resolution that enables not only cell tracking, but also the observation of a variety of cellular responses. We describe an approach in detail that allows for the continuous time-lapse imaging of cells during the drug response for essentially as long as desired, typically up to 96 hr. Using variations of the approach, cells can be monitored for weeks. With the employment of genetically encoded fluorescent biosensors numerous processes, pathways and responses can be followed. We show examples that include tracking and quantification of cell growth and cell cycle progression, chromosome dynamics, DNA damage, and cell death. We also discuss variations of the technique and its flexibility, and highlight some common pitfalls.

  19. Technical note: Stage and water width measurement of a mountain stream using a simple time-lapse camera

    Directory of Open Access Journals (Sweden)

    P. Leduc

    2018-01-01

    Full Text Available Remote sensing applied to river monitoring adds complementary information useful for understanding the system behaviour. In this paper, we present a method for visual stage gauging and water surface width measurement using a ground-based time-lapse camera and a fully automatic image analysis algorithm for flow monitoring at a river cross section of a steep, bouldery channel. The remote stage measurement was coupled with a water level logger (pressure transducer on site and shows that the image-based method gives a reliable estimate of the water height variation and daily flow record when validated against the pressure transducer (R = 0.91. From the remotely sensed pictures, we also extracted the water width and show that it is possible to correlate water surface width and stage. The images also provide valuable ancillary information for interpreting and understanding flow hydraulics and site weather conditions. This image-based gauging method is a reliable, informative and inexpensive alternative or adjunct to conventional stage measurement especially for remote sites.

  20. Technical note: Stage and water width measurement of a mountain stream using a simple time-lapse camera

    Science.gov (United States)

    Leduc, Pauline; Ashmore, Peter; Sjogren, Darren

    2018-01-01

    Remote sensing applied to river monitoring adds complementary information useful for understanding the system behaviour. In this paper, we present a method for visual stage gauging and water surface width measurement using a ground-based time-lapse camera and a fully automatic image analysis algorithm for flow monitoring at a river cross section of a steep, bouldery channel. The remote stage measurement was coupled with a water level logger (pressure transducer) on site and shows that the image-based method gives a reliable estimate of the water height variation and daily flow record when validated against the pressure transducer (R = 0.91). From the remotely sensed pictures, we also extracted the water width and show that it is possible to correlate water surface width and stage. The images also provide valuable ancillary information for interpreting and understanding flow hydraulics and site weather conditions. This image-based gauging method is a reliable, informative and inexpensive alternative or adjunct to conventional stage measurement especially for remote sites.

  1. Inversion of high resolution 3-D shallow velocity structures in Ilan plain using local dense seismic network

    Science.gov (United States)

    Su, P.; Chen, P.; Chang, C.

    2013-12-01

    The Ilan Plain (IP) in NE Taiwan locates at the south termination of the Okinawa Trough featuring with intense seismic activity and potential geothermal resources. In this study, we aim at inverting high resolution 3-D shallow velocity structures to better understanding the temperature and/or fluid distributions beneath IP for geothermal explorations. We apply FMTOMO (Rawlinson et al., 2006) to conduct the inversion in two phases based on data availability. In phase one, we use P and S arrival times of local earthquakes in the past (2001~2012) as mainly recorded by Taiwan Strong Motion Instrument Program (TSMIP) network run by Central Weather Bureau (CWB). The average station interval of TSMIP in IP is ~4 km and, together with high seismic activity herein, checkerboard tests indicate that anomalies of 4 cubic km can be resolved at the depth of 6 km where the resolution is optimal. Results of inversion show that while low velocity anomalies and high Vp/Vs ratio mainly distribute over the shallow depth (0~5 km) of N IP, they also correspond well to known geothermal areas in S IP, e.g., the Chingshui Geothermal Field. The main tasks of phase two are to improve the resolution of inversion for S IP to better constrain the underground areas of known geothermal sites. To this end, a temporary network of 43 Texans instruments (REFTEK 125A) was evenly deployed across S IP in Jun. 2013 and assuming the same event distributions as past, the resolution can be improved to be 2~3 cubic km for target depths in S IP. We expect that future phase-two results can provide reliable indications for geothermal explorations.

  2. Velocity and structural model of the Lower Tagus Basin according to the study of environmental seismic noise

    Science.gov (United States)

    Gomes Torres, Ricardo Jorge; Furtado, José Augusto; Gonçalves Silva, Hugo; Borges, José Fernando; Caldeira, Bento; Bezzeghoud, Mourad; Carvalho, João

    2013-04-01

    Along his history the Lower Tagus Valley (LTV) region was shaken by several earthquakes, some of them produced in large ruptures of offshore structures located southwest of the Portuguese coastline. Among these is the Lisbon earthquake of 1 November 1755 (M~8.5-8.7), and other moderates earthquakes that were produced by local sources such as the 1344 (M6.0), 1531 (M7.1) and 1909 (M6.0) earthquakes. Previous simulations [1] have shown high velocity amplification in the region. The model used in the simulations was updated from low to high resolution using all the new available geophysical and geotechnical data on the area (seismic reflection, aeromagnetic, gravimetric, deep wells and geological outcrops) [2]. To confirm this model in the areas where it was derived by potential field methods we use broadband ambient noise measurements collected in about 200 points along seven profiles on the LTV basin, six perpendicular and one parallel to the basin axis. We applied the horizontal to vertical (H/V) spectral ratio method [3] to the seismic noise profiles in order to estimate the distribution of amplification in the basin. The H/V curves obtained reveals the existence of two low frequency peaks centered on 0.2 and 1 Hz [4]. These peaks are strongly related with the thickness of Cenozoic and alluvial sediments. The velocity model obtained by inversion of the H/V curves is in good agreement with borehole data, and results obtained using seismic reflection and gravimetric methods. However, aeromagnetic data overestimates the depth of the base of Cenozoic in the areas where it overlies directly the paleozoic basement, which we attribute either to the existence of Mesozoic units or higher magnetic susceptibilities than expected for the Paleozoic. References: [1] Bezzeghoud, M., Borges, J.F., M., Caldeira (2011). Ground motion simulations of the SW Iberia margin: rupture directivity and earth structure effects. Natural Hazards, pages 1-17. doi:10.1007/s11069-011-9925-2 [2

  3. Long and Short Term GPS Velocity Change in South Peru and North Chile Seismic Gap: towards the Small SSE Detection.

    Science.gov (United States)

    Jara, J.; Socquet, A.; Walpersdorf, A.; Rousset, B.; Marsan, D.

    2016-12-01

    For more than 20 years, the GPS data have been used to try to understand the different phases of the seismic cycle. Coseismic and postseismic displacements were modeled, and SSEs were discovered in the early 2000'. Those events have shed light of the subduction mechanical properties in long/short term (e.g. coupling factor, dip/strike segmentation, asperity location ). From GPS residual time series is possible see that the GPS signal can not be fully explained by these relatively simple phases of the seismic cycle. Instead, we observe that a residual signal can be evidenced and seems to be related with unmodeled transient deformation, likely small slow slip events. The aim of this work is to understand and characterize the masked transient events in the GPS time series. The database used in this study is made of 66 continuous GPS stations over 15 years in the South Peru - North Chile Seismic Gap. Those data were processed with GAMIT software, and the first order interseismic, coseismic and postseismic signal have been removed to obtain the residual time series. Velocity changes were calculated using a mean sliding window over 1 year, 6 and 3 months. This has allowed detecting clear velocity anomalies. Such is the case of Pisagua Earthquake (Mw 8.2, Chile, 2014) where the data seems to reveal a long precursory phase of around 8 months. In order to complement these findings, and understand whether these transients occur on a steady state manner or as a series of creep bursts, we analyze the time series using a cross correlation technique to detect small transient events. Several positive correlations were detected on shorter-term windows (15,30 and 60 days). This might mean that small SSEs occur in the area. In order to distinguish real events from artifacts produced by the model, several synthetics time series were calculated to see what is the minimum correlation value capable to make real SSE detection. From those results, the magnitude and possible location have

  4. Seismic velocities and geologic logs from boreholes at three downhole arrays in San Francisco, California

    Science.gov (United States)

    Gibbs, James F.; Fumal, Thomas E.; Borcherdt, Roger D.; Warrick, Richard E.; Liu, Hsi-Ping; Westerlund, Robert E.

    1994-01-01

    The Loma Prieta earthquake of October 17, 1989 (1704 PST), has reinforced observations made by Wood and others (1908) after the 1906 San Francisco earthquake, that poor ground conditions (soft soil) increase the likelihood of shaking damage to structures. Since 1908 many studies (for example Borcherdt, 1970, Borcherdt and Gibbs, 1976, Borcherdt and Glassmoyer, 1992) have shown that soft soils amplify seismic waves at frequencies that can be damaging to structures. Damage in the City of San Francisco from the Loma Prieta earthquake was concentrated in the Marina District, the Embarcadero, and the China Basin areas. Each of these areas, to some degree, is underlain by soft soil deposits. These concentrations of damage raise important questions regarding the amplification effects of such deposits at damaging levels of motion. Unfortunately, no strong-motion recordings were obtained in these areas during the Loma Prieta earthquake and only a limited number (< 10) have been obtained on other soft soil sites in the United States. Consequently, important questions exist regarding the response of such deposits during damaging earthquakes, especially questions regarding the nonlinear soil response. Towards developing a data set to address these important questions, borehole strong-motion arrays have been installed at three locations. These arrays consist of groups of wide-dynamic-range pore-pressure transducers and three-component accelerometers, the outputs of which are recorded digitally. The arrays are designed to provide an integrated set of data on ground shaking, liquifaction-induced ground failure, and structural response. This report describes the detailed geologic, seismic, and material-property determinations derived at each of these sites.

  5. Continental lithospheric subduction and intermediate-depth seismicity: Constraints from S-wave velocity structures in the Pamir and Hindu Kush

    Science.gov (United States)

    Li, Wei; Chen, Yun; Yuan, Xiaohui; Schurr, Bernd; Mechie, James; Oimahmadov, Ilhomjon; Fu, Bihong

    2018-01-01

    The Pamir has experienced more intense deformation and shortening than Tibet, although it has a similar history of terrane accretion. Subduction as a primary way to accommodate lithospheric shortening beneath the Pamir has induced the intermediate-depth seismicity, which is rare in Tibet. Here we construct a 3D S-wave velocity model of the lithosphere beneath the Pamir by surface wave tomography using data of the TIPAGE (Tien Shan-Pamir Geodynamic program) and other seismic networks in the area. We imaged a large-scale low velocity anomaly in the crust at 20-50 km depth in the Pamir overlain by a high velocity anomaly at a depth shallower than 15 km. The high velocity anomalies colocate with exposed gneiss domes, which may imply a similar history of crustal deformation, partial melting and exhumation in the hinterland, as has occurred in the Himalaya/Tibet system. At mantle depths, where the intermediate-depth earthquakes are located, a low velocity zone is clearly observed extending to about 180 km and 150 km depth in the Hindu Kush and eastern Pamir, respectively. Moreover, the geometry of the low-velocity anomaly suggests that lower crustal material has been pulled down into the mantle by the subducting Asian and Indian lithospheric mantle beneath the Pamir and Hindu Kush, respectively. Metamorphic processes in the subducting lower crust may cause the intermediate-depth seismicity down to 150-180 km depth beneath the Pamir and Hindu Kush. We inverted focal mechanisms in the seismic zone for the stress field. Differences in the stress field between the upper and lower parts of the Indian slab imply that subduction and detachment of the Indian lithosphere might cause intense seismicity associated with the thermal shear instability in the deep Hindu Kush.

  6. How a joint interpretation of seismic scattering, velocity, and attenuation models explains the nature of the Campi Flegrei (Italy).

    Science.gov (United States)

    Calo, M.; Tramelli, A.

    2017-12-01

    Seismic P and S velocity models (and their ratio Vp/Vs) help illuminating the geometrical structure of the bodies and give insight on the presence of water, molten or gas saturated regions. Seismic attenuation represents the anelastic behavior of the medium. Due to its dependence on temperature, fluid contents and cracks presence, this parameter is also largely used to characterize the structures of volcanoes and geothermal areas. Scattering attenuation is related, in the upper crust, to the amount, size and organization of the fractures giving complementary information on the state of the medium.Therefore a joint interpretation of these models provides an exhaustive view of the elastic parameters in volcanic regions. Campi Flegrei is an active Caldera marked by strong vertical deformations of the ground called bradyseisms and several models have been proposed to describe the nature and the geometry of the bodies responsible of the bradyseisms. Here we show Vp, Vp/Vs, Qp and scattering models carried out by applying an enhanced seismic tomography method that combines de double difference approach (Zhang and Thurber, 2003) and the Weigthed Average Method (Calò et al., 2009, Calò et al., 2011, 2013). The data used are the earthquakes recorded during the largest bradyseism crisis of the 80's. Our method allowed to image structures with linear dimension of 0.5-1.2km, resulting in an improvement of the resolving power at least two times of the other published models (e.g. Priolo et al., 2012). The joint interpretation of seismic models allowed to discern small anomalous bodies at shallow depth (0.5-2.0 km) marked by relatively low Vp, high Vp/Vs ratio and low Qp values associated with the presence of shallow geothermal water saturated reservoir from regions with low Vp, low Vp/Vs and low Qp related to the gas saturated part of the reservoir. At deeper depth (2-3.5 km) bodies with high Vp and Vp/Vs and low Qp are associated with magmatic intrusions. The Scattering

  7. Pervasive seismic low-velocity zones within stagnant plates in the mantle transition zone: Thermal or compositional origin?

    Science.gov (United States)

    Tauzin, B.; Kim, S.; Kennett, B. L. N.

    2017-11-01

    We exploit conversions between P and S waves for large-scale, high-resolution imaging of the mantle transition zone beneath Northwest Pacific and the margin of Eastern Asia. We find pervasive reflectivity concentrated in two bands with apparent wave-speed reduction of -2% to -4% about 50 km thick at the top of the transition zone and 100 km thick at the bottom. This negative reflectivity associated with the scattered-waves at depth is interpreted jointly with larger-scale mantle tomographic images, and is shown to delineate the stagnant portions of the subducted Pacific plate in the transition zone, with largely positive shear-wave velocity contrasts. The upper reflectivity zone connects to broad low-velocity regions below major intra-plate volcanoes, whereas the lower zone coincides locally with the occurrence of deep-focus earthquakes along the East Asia margin. Similar reflectivity is found in Pacific Northwest of the USA. We demonstrate that the thermal signature of plates alone is not sufficient to explain such features. Alternative explanations for these reflective zones include kinetic effects on olivine phase transitions (meta-stability), compositional heterogeneities within and above stagnant plates, complex wave-propagation effects in the heterogeneous slab structure, or a combination of such factors. We speculate that part of the negative reflectivity is the signature of compositional heterogeneities, as revealed by numerous other studies of seismic scattering throughout the mantle, and that such features could be widespread across the globe.

  8. A new method for identification of protocatagenesis, mesocatagenesis, and apocatagenesis zones in a terrigenous sedimentary cover by applying layer seismic velocities

    Science.gov (United States)

    Lazurkin, D. V.

    2011-03-01

    This method pertains to oil and gas geology and to geology of sedimentary basins prospective for oil and gas. It includes identifying catagenesis zones in drilled areas within the sedimentary cover of the basin based on assay results for drill cores and cuttings using the standard methods. Analysis is primarily made in order to determine rock catagenesis based on the optical characteristics of vitrinite. A correlation between catagenesis zones and layer seismic velocities obtained from regional and exploration seismic data is made for a drilled area. Both the layer seismic velocities and the degree of rock catagenesis increase with depth under the influence of increasing rock density. Correlations between layer velocities and the degree of rock catagenesis have been established. The following ratios have been determined for the Scotian shelf, Canada, and the Barents shelf, Russia: a protocatagenesis zone (the cap) corresponds to layer seismic velocities ( V lay) of 1.5-3.3 km/s, a mesocatagenesis zone (the principal hydrocarbon generation area) corresponds to V lay of 3.3-5.0 km/s, and an apocatagenesis zone (an area with a very low hydrocarbon potential) corresponds to V lay of over 5.0 km/s. An advantage of the new method of identification of catagenesis zones is that it can be used prior to drilling. Its conceptual originality and cost efficiency lie precisely in this.

  9. Seismic detection of fault zone hydrocarbon conduit-seal potential using velocity, frequency, and Q analysis: La Concepcion Field, Lake Maracaibo Venezuela example

    Science.gov (United States)

    Alahdal, Ahmed Omar

    The 3-D Post-Stack Time Migrated Seismic Data of La Concepcion Field, Maracaibo Basin, Venezuela cover an existing field with known oil and gas pay zones. The thesis problem is how to use this seismic data in an interpretation of leaky faults that occur in the exploration area of interest. A solution to the problem was obtained using an integrated geophysical approach that included published seismic attribute methods (Variance Cube, Geoframe IESX). Specific developments in this thesis to solve the interpretation problem of leaky faults in the region include (1) an image ray perturbation approach for updating the interval velocity in a faulted domain (2) a peak frequency approach to attenuation estimation within intervals and (3) a scaled interpretation of the velocity measurements at sonic, checkshot and surface seismic reflection data. The first development refines the interval velocities within fracture zones. The second development identifies anomalous attenuation most likely due to the presence of gas. The combined effects of low interval velocity and high attenuation are interpreted to be signs of leaking faults.

  10. Joint inversion of seismic velocities and source location without rays using the truncated Newton and the adjoint-state method

    Science.gov (United States)

    Virieux, J.; Bretaudeau, F.; Metivier, L.; Brossier, R.

    2013-12-01

    Simultaneous inversion of seismic velocities and source parameters have been a long standing challenge in seismology since the first attempts to mitigate trade-off between very different parameters influencing travel-times (Spencer and Gubbins 1980, Pavlis and Booker 1980) since the early development in the 1970s (Aki et al 1976, Aki and Lee 1976, Crosson 1976). There is a strong trade-off between earthquake source positions, initial times and velocities during the tomographic inversion: mitigating these trade-offs is usually carried empirically (Lemeur et al 1997). This procedure is not optimal and may lead to errors in the velocity reconstruction as well as in the source localization. For a better simultaneous estimation of such multi-parametric reconstruction problem, one may take benefit of improved local optimization such as full Newton method where the Hessian influence helps balancing between different physical parameter quantities and improving the coverage at the point of reconstruction. Unfortunately, the computation of the full Hessian operator is not easily computed in large models and with large datasets. Truncated Newton (TCN) is an alternative optimization approach (Métivier et al. 2012) that allows resolution of the normal equation H Δm = - g using a matrix-free conjugate gradient algorithm. It only requires to be able to compute the gradient of the misfit function and Hessian-vector products. Traveltime maps can be computed in the whole domain by numerical modeling (Vidale 1998, Zhao 2004). The gradient and the Hessian-vector products for velocities can be computed without ray-tracing using 1st and 2nd order adjoint-state methods for the cost of 1 and 2 additional modeling step (Plessix 2006, Métivier et al. 2012). Reciprocity allows to compute accurately the gradient and the full Hessian for each coordinates of the sources and for their initial times. Then the resolution of the problem is done through two nested loops. The model update Δm is

  11. Monitoring infiltration with time-lapse relative gravity: An option for non-invasive determination of soil hydraulic parameters?

    Science.gov (United States)

    Bauer-Gottwein, P.

    2012-04-01

    Various hydrogeophysical methods have been proposed to monitor infiltration and determine soil hydraulic parameters using coupled hydrogeophysical inversion. Methods include electrical resistivity tomography (ERT), ground penetrating radar (GPR, both surface and cross-hole) as well as passive microwave radiometry. Depending on the measurement set-up, both ERT and GPR can provide high-resolution images of soil water content. However, soil water content monitoring with both ERT and GPR depends on the validity and accuracy of empirical relationships linking soil water content to electrical resistivity (ERT) and dielectric permittivity (GPR). This has emerged as one of the main limitations for the performance of soil water monitoring with both GPR and ERT. As an alternative, ground-based time-lapse relative gravity (TLRG) is proposed for infiltration monitoring. The method is based on the fact that water content changes in the subsurface constitute changes in subsurface density and can be monitored as changes in the gravitational field. The advantage of TLRG over GPR and ERT is that TLRG directly senses mass changes. Thus, no empirical relationship is required to link water content changes to changes in a geophysical property. This study evaluates the performance of TLRG for infiltration monitoring and hydrogeophysical inversion of soil hydraulic parameters. Results include both synthetic infiltration experiments and a real-world infiltration experiment monitored with TLRG. In the synthetic experiments, soil water content profiles are generated using analytical infiltration solutions. Soil water content profiles are translated into gravity signals and are corrupted with random noise to produce synthetic data. The synthetic data is subsequently used in a hydrogeophysical inversion of soil hydraulic parameters. Fitted parameter confidence intervals and covariances are evaluated. The same inversion procedure is used on the real-world data. The results show that TLRG data

  12. Segmentation of Environmental Time Lapse Image Sequences for the Determination of Shore Lines Captured by Hand-Held Smartphone Cameras

    Science.gov (United States)

    Kröhnert, M.; Meichsner, R.

    2017-09-01

    The relevance of globally environmental issues gains importance since the last years with still rising trends. Especially disastrous floods may cause in serious damage within very short times. Although conventional gauging stations provide reliable information about prevailing water levels, they are highly cost-intensive and thus just sparsely installed. Smartphones with inbuilt cameras, powerful processing units and low-cost positioning systems seem to be very suitable wide-spread measurement devices that could be used for geo-crowdsourcing purposes. Thus, we aim for the development of a versatile mobile water level measurement system to establish a densified hydrological network of water levels with high spatial and temporal resolution. This paper addresses a key issue of the entire system: the detection of running water shore lines in smartphone images. Flowing water never appears equally in close-range images even if the extrinsics remain unchanged. Its non-rigid behavior impedes the use of good practices for image segmentation as a prerequisite for water line detection. Consequently, we use a hand-held time lapse image sequence instead of a single image that provides the time component to determine a spatio-temporal texture image. Using a region growing concept, the texture is analyzed for immutable shore and dynamic water areas. Finally, the prevalent shore line is examined by the resultant shapes. For method validation, various study areas are observed from several distances covering urban and rural flowing waters with different characteristics. Future work provides a transformation of the water line into object space by image-to-geometry intersection.

  13. Proliferation of pulmonary endothelial cells: time-lapse cinematography of growth to confluence and restitution of monolayer after wounding.

    Science.gov (United States)

    Ryan, U S; Absher, M; Olazabal, B M; Brown, L M; Ryan, J W

    1982-01-01

    A fundamental characteristic of vascular endothelium is that it exists as a monolayer, a condition that must be met in both vascular growth and repair. Maintenance of the monolayer is important both for the exchange of nutrients and for interactions between blood solutes and endothelial enzymes and transport systems. We have used time-lapse cinematography to compare proliferative behavior of bovine pulmonary endothelial cells in (1) establishment of a monolayer from a low-density seed (7.5 X 10(4) cells in a 60 mm dish) and (2) restitution of a confluent monolayer (approx. 2.9 x 10(6) cells in a 60 mm dish) following a mechanical wound (removal of cells from an area 5 x 15 mm by scraping). Culture 2 was not refed after wounding. In culture 2, approx. 30% of the cells accounted for repopulation (confluence in 40 hr). In culture 1, all cells entered into division. Participating cells of culture 2 began division immediately (69 divisions/filmed area in 10 hr, vs. four divisions in culture 1). Interdivision times (IDT) were longer and relatively constant in culture 1 until near confluence; none were less than 10 h, whereas in 2, 24% of the IDT's were less than or equal to 10 hr. Remarkably, IDTs of culture 2 decreased steadily until confluence was re-established. Cell migration in culture 1 was multidirectional while direction of migration in culture 2 was always into the wound area. Mean migration rate (MIG) in culture 2 was related to the site of origin of the cells, those dividing farthest from the unwounded area had fastest MIGs. Neither culture formed more than a single layer of cells. Although the cell kinetics of cultures 1 and 2 differed, the same goal, confluence, was achieved in either case.

  14. Documentation of normal and leukemic myelopoietic progenitor cells with high-resolution phase-contrast time-lapse cinematography.

    Science.gov (United States)

    Boll, I T

    2001-08-01

    The high-resolution phase-contrast, time-lapse cinematography using oil immersion lenses and 16-mm film demonstrates the kinetic cell events as maturation, locomotion, mitosis, and apoptosis of cells cultivated at 37 degrees C for up to 10 days. 0.5 v/v frozen-thawed sera with presumably high cytokine concentrations were added to the plasma or agar clot. Vital progenitor cells from human bone marrow and blood have a large, bright, unstructured nucleus with a large nucleolus and a narrow rim of cytoplasm (nuclear/cytoplasmic volume ratio = 0.7). Their nuclei are 6-14 micrometer in diameter and double their volume within 8 h. Many (70%) move at a mean speed of 2 micrometer/min, and many (30%) multiply with alpha-2alpha mitoses, generating progenitor cell families. Various disturbances during the course of mitosis lead to the formation of polyploid cells, thereby yielding the megakaryocytic cell line. Some of the progenitor cells undergo asymmetric alpha-alphan mitoses: One of the two initially identical daughter cells remains a progenitor cell in the morphological sense, whereas the other daughter cell - depending on the size of its mother cell - matures in the same culture medium to form a granulocytopoietic, monocytopoietic or erythrocytopoietic cell line. - In acute myeloid leukemias (AML), the blasts and their nuclei are slightly larger than the corresponding progenitor cells and move faster (5 micrometer/min). Symmetric alpha-2alpha mitoses permit unlimited multiplication of the leukemic blasts if contact with cytotoxic lymphocytes does not render them apoptotic. This results in more stromal cells than normal. Granulocytopenia, monocytopenia, and anemia occur due to the genetic impairment of signaling control for asymmetric alpha-alphan mitoses, and thrombocytopenia occurs due to the reduction in polyploidization. Copyright 2001 S. Karger GmbH, Freiburg

  15. 2D Time-lapse Resistivity Monitoring of an Organic Produced Gas Plume in a Landfill using ERT.

    Science.gov (United States)

    Amaral, N. D.; Mendonça, C. A.; Doherty, R.

    2014-12-01

    This project has the objective to study a landfill located on the margins of Tietê River, in São Paulo, Brazil, using the electroresistivity tomography method (ERT). Due to huge organic matter concentrations in the São Paulo Basin quaternary sediments, there is subsurface depth related biogas accumulation (CH4 and CO2), induced by anaerobic degradation of the organic matter. 2D resistivity sections were obtained from a test area since March 2012, a total of 7 databases, being the last one dated from October 2013. The studied line has the length of 56m, the electrode interval is of 2m. In addition, there are two boreholes along the line (one with 3 electrodes and the other one with 2) in order to improve data quality and precision. The boreholes also have a multi-level sampling system that indicates the fluid (gas or water) presence in relation to depth. With our results it was possible to map the gas plume position and its area of extension in the sections as it is a positive resistivity anomaly, with the gas level having approximately 5m depth. With the time-lapse analysis (Matlab script) between the obtained 2D resistivity sections from the site, it was possible to map how the biogas volume and position change in the landfill in relation to time. Our preliminary results show a preferential gas pathway through the subsurface studied area. A consistent relation between the gas depth and obtained microbiological data from archea and bacteria population was also observed.

  16. Gas piston activity of the Nyiragongo lava lake: First insights from a Stereographic Time-Lapse Camera system

    Science.gov (United States)

    Smets, Benoît; d'Oreye, Nicolas; Kervyn, Matthieu; Kervyn, François

    2017-10-01

    Nyiragongo volcano (D.R. Congo), in the western branch of the East African Rift System, is one of the most active volcanoes on Earth. Its eruptive activity is mainly characterized by the presence of a persistent lava lake in its main crater. As observed at other persistent lava lakes, the Nyiragongo lava lake level exhibits metric vertical variations in the form of minutes-to hour-long cycles, which we infer to be gas piston activity. To study this activity, we developed and tested a Stereographic Time-Lapse Camera (STLC) system, which takes stereo-pairs of photographs of the Nyiragongo crater at regular intervals. Each pair of gas- and steam-free images during daytime allows the production of a 3D point cloud. The comparison of the point clouds provides a measurement of topographic changes related to variations in lava lake level. The processing of a first dataset acquired between 18 and 20 September 2011, at an acquisition rate of 1 pair of images every 2 min, revealed cycles of vertical lava lake level variations reaching up to 3.8 m. Lava lake level variations >0.5 m are detected significantly. They are interpreted to result from gas accumulation and release in the lava lake itself. The limitations of the STLC approach are related to the number of cameras used and the atmospheric masking by steam and volcanic gas in the Nyiragongo crater. The proposed photogrammetric approach could be applied elsewhere or in other disciplines, where frequent topographic changes occur.

  17. Time-lapse downhole electrical resistivity monitoring of subsurface CO2 storage at the Maguelone shallow experimental site (Languedoc, France)

    Science.gov (United States)

    Denchik, Nataliya; Pezard, Philippe; Lofi, Johanna; Perroud, Hervé; Neyens, Denis; Luquot, Linda

    2015-04-01

    A shallow field experimental site for CO2 injection was established at Maguelone (Languedoc,France), in order to test in an integrated manner a suite of surface and downhole hydrogeophysical monitoring methods. The objective is to improve our understanding of gas transport in the shallow subsurface and to determine the sensitivity of CO2 monitoring systems for leakage detection. The site offers a natural laboratory to study the processes associated with CO2 injection in a clastic and clay-rich context saturated with saline fluids. Prior to CO2injection, three nitrogen (N2) injections were undertaken in 2012 to measure the site response to neutral gas injection. In 2013, a volume of 111 m3 of CO2 was injected during 3.5 hours at 15 meter depth. During each experiment, the gas plumes were successfully detected from pressure monitoring, time-lapse induction logging and downhole resistivity monitoring with downhole dipole-dipole arrays. Increases in resistivity are attributed to free gas propagation (either N2 or CO2) whereas decreases in resistivity correlate with CO2 dissolution in the pore fluid. Chemical analyses confirm this hypothesis with a decrease in pH and an increase in the concentration of dissolved species in the later case. The next stage of the project will be performing the CO2 injection experiments with improved monitoring schema using results of the present study. In perspective, besides of improving our understanding of gas transport in the shallow subsurface, the additional issues could not just show a capability of used geophysical and geochemical techniques to monitor the CO2 plume and to detect near-surface CO2 migration pathways, but to help quantifying potential CO2 migration.

  18. AnimalFinder: A semi-automated system for animal detection in time-lapse camera trap images

    Science.gov (United States)

    Price Tack, Jennifer L.; West, Brian S.; McGowan, Conor P.; Ditchkoff, Stephen S.; Reeves, Stanley J.; Keever, Allison; Grand, James B.

    2017-01-01

    Although the use of camera traps in wildlife management is well established, technologies to automate image processing have been much slower in development, despite their potential to drastically reduce personnel time and cost required to review photos. We developed AnimalFinder in MATLAB® to identify animal presence in time-lapse camera trap images by comparing individual photos to all images contained within the subset of images (i.e. photos from the same survey and site), with some manual processing required to remove false positives and collect other relevant data (species, sex, etc.). We tested AnimalFinder on a set of camera trap images and compared the presence/absence results with manual-only review with white-tailed deer (Odocoileus virginianus), wild pigs (Sus scrofa), and raccoons (Procyon lotor). We compared abundance estimates, model rankings, and coefficient estimates of detection and abundance for white-tailed deer using N-mixture models. AnimalFinder performance varied depending on a threshold value that affects program sensitivity to frequently occurring pixels in a series of images. Higher threshold values led to fewer false negatives (missed deer images) but increased manual processing time, but even at the highest threshold value, the program reduced the images requiring manual review by ~40% and correctly identified >90% of deer, raccoon, and wild pig images. Estimates of white-tailed deer were similar between AnimalFinder and the manual-only method (~1–2 deer difference, depending on the model), as were model rankings and coefficient estimates. Our results show that the program significantly reduced data processing time and may increase efficiency of camera trapping surveys.

  19. PFLOTRAN-E4D: A parallel open source PFLOTRAN module for simulating time-lapse electrical resistivity data

    Science.gov (United States)

    Johnson, Timothy C.; Hammond, Glenn E.; Chen, Xingyuan

    2017-02-01

    Time-lapse electrical resistivity tomography (ERT) is finding increased application for remotely monitoring processes occurring in the near subsurface in three-dimensions (i.e. 4D monitoring). However, there are few codes capable of simulating the evolution of subsurface resistivity and corresponding tomographic measurements arising from a particular process, particularly in parallel and with an open source license. Herein we describe and demonstrate an electrical resistivity tomography module for the PFLOTRAN subsurface flow and reactive transport simulation code, named PFLOTRAN-E4D. The PFLOTRAN-E4D module operates in parallel using a dedicated set of compute cores in a master-slave configuration. At each time step, the master processes receives subsurface states from PFLOTRAN, converts those states to bulk electrical conductivity, and instructs the slave processes to simulate a tomographic data set. The resulting multi-physics simulation capability enables accurate feasibility studies for ERT imaging, the identification of the ERT signatures that are unique to a given process, and facilitates the joint inversion of ERT data with hydrogeological data for subsurface characterization. PFLOTRAN-E4D is demonstrated herein using a field study of stage-driven groundwater/river water interaction ERT monitoring along the Columbia River, Washington, USA. Results demonstrate the complex nature of subsurface electrical conductivity changes, in both the saturated and unsaturated zones, arising from river stage fluctuations and associated river water intrusion into the aquifer. The results also demonstrate the sensitivity of surface based ERT measurements to those changes over time. PFLOTRAN-E4D is available with the PFLOTRAN development version with an open-source license at https://bitbucket.org/pflotran/pflotran-dev.

  20. PFLOTRAN-E4D: A parallel open source PFLOTRAN module for simulating time-lapse electrical resistivity data

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Timothy C.; Hammond, Glenn E.; Chen, Xingyuan

    2017-02-01

    Time-lapse electrical resistivity tomography (ERT) is finding increased application for remotely monitoring processes occurring in the near subsurface in three-dimensions (i.e. 4D monitoring). However, there are few codes capable of simulating the evolution of subsurface resistivity and corresponding tomographic measurements arising from a particular process, particularly in parallel and with an open source license. Herein we describe and demonstrate an electrical resistivity tomography module for the PFLOTRAN subsurface simulation code, named PFLOTRAN-E4D. The PFLOTRAN-E4D module operates in parallel using a dedicated set of compute cores in a master-slave configuration. At each time step, the master processes receives subsurface states from PFLOTRAN, converts those states to bulk electrical conductivity, and instructs the slave processes to simulate a tomographic data set. The resulting multi-physics simulation capability enables accurate feasibility studies for ERT imaging, the identification of the ERT signatures that are unique to a given process, and facilitates the joint inversion of ERT data with hydrogeological data for subsurface characterization. PFLOTRAN-E4D is demonstrated herein using a field study of stage-driven groundwater/river water interaction ERT monitoring along the Columbia River, Washington, USA. Results demonstrate the complex nature of changes subsurface electrical conductivity, in both the saturated and unsaturated zones, arising from water table changes and from river water intrusion into the aquifer. The results also demonstrate the sensitivity of surface based ERT measurements to those changes over time. PFLOTRAN-E4D is available with the PFLOTRAN development version with an open-source license at https://bitbucket.org/pflotran/pflotran-dev .

  1. Combined time-lapse magnetic resonance imaging and modeling to investigate colloid deposition and transport in porous media.

    Science.gov (United States)

    Lehoux, Alizée P; Faure, Pamela; Lafolie, François; Rodts, Stéphane; Courtier-Murias, Denis; Coussot, Philippe; Michel, Eric

    2017-10-15

    Colloidal particles can act as vectors of adsorbed pollutants in the subsurface, or be themselves pollutants. They can reach the aquifer and impair groundwater quality. The mechanisms of colloid transport and deposition are often studied in columns filled with saturated porous media. Time-lapse profiles of colloid concentration inside the columns have occasionally been derived from magnetic resonance imaging (MRI) data recorded in transport experiments. These profiles are valuable, in addition to particle breakthrough curves (BTCs), for testing and improving colloid transport models. We show that concentrations could not be simply computed from MRI data when both deposited and suspended colloids contributed to the signal. We propose a generic method whereby these data can still be used to quantitatively appraise colloid transport models. It uses the modeled suspended and deposited particle concentrations to compute modeled MRI data that are compared to the experimental data. We tested this method by performing transport experiments with sorbing colloids in sand, and assessed for the first time the capacity of the model calibrated from BTCs to reproduce the MRI data. Interestingly, the dispersion coefficient and deposition rate calibrated from the BTC were respectively overestimated and underestimated compared with those calibrated from the MRI data, suggesting that these quantities, when determined from BTCs, need to be interpreted with care. In a broader perspective, we consider that combining MRI and modeling offers great potential for the quantitative analysis of complex MRI data recorded during transport experiments in complex environmentally relevant porous media, and can help improve our understanding of the fate of colloids and solutes, first in these media, and later in soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. In vivo time-lapse imaging of skin burn wound healing using second-harmonic generation microscopy

    Science.gov (United States)

    Yasui, Takeshi; Tanaka, Ryosuke; Hase, Eiji; Fukushima, Shu-ichiro; Araki, Tsutomu

    2014-02-01

    Wound healing is a process to repair the damaged tissue caused by thermal burn, incised wound, or stab wound. Although the wound healing has many aspects, it is common for dynamics of collagen fiber, such as decomposition, production, or growth, to be closely related with wound healing. If such the healing process can be visualized as a timelapse image of the collagen fiber in the same subject, one may obtain new findings regarding biological repairing mechanisms in the healing process. In this article, to investigate the temporal modoification of dermal collagen fiber in the burn wound healing, we used second-harmonic-generation (SHG) microscopy, showing high selectivity and good image contrast to collagen molecules as well as high spatial resolution, optical three-dimensional sectioning, minimal invasiveness, deep penetration, the absence of interference from background light, and in vivo measurement without additional staining. Since SHG light arises from a non-centrosymmetric triple helix of three polypeptide chains in the collagen molecule, SHG intensity sensitively reflects the structure maturity of collagen molecule and its aggregates. A series of time-lapse SHG images during the wound healing process of 2 weeks clearly indicated that condensation and melting of dermal collagen fibers by the deep dermal burn, decomposition of the damaged collagen fibers in the inflammation phase, production of new collagen fibers in the proliferation phase, and the growth of the new collagen fibers in the remodeling phase. These results show a high potential of SHG microscopy for optical assessment of the wound healing process in vivo.

  3. SEGMENTATION OF ENVIRONMENTAL TIME LAPSE IMAGE SEQUENCES FOR THE DETERMINATION OF SHORE LINES CAPTURED BY HAND-HELD SMARTPHONE CAMERAS

    Directory of Open Access Journals (Sweden)

    M. Kröhnert

    2017-09-01

    Full Text Available The relevance of globally environmental issues gains importance since the last years with still rising trends. Especially disastrous floods may cause in serious damage within very short times. Although conventional gauging stations provide reliable information about prevailing water levels, they are highly cost-intensive and thus just sparsely installed. Smartphones with inbuilt cameras, powerful processing units and low-cost positioning systems seem to be very suitable wide-spread measurement devices that could be used for geo-crowdsourcing purposes. Thus, we aim for the development of a versatile mobile water level measurement system to establish a densified hydrological network of water levels with high spatial and temporal resolution. This paper addresses a key issue of the entire system: the detection of running water shore lines in smartphone images. Flowing water never appears equally in close-range images even if the extrinsics remain unchanged. Its non-rigid behavior impedes the use of good practices for image segmentation as a prerequisite for water line detection. Consequently, we use a hand-held time lapse image sequence instead of a single image that provides the time component to determine a spatio-temporal texture image. Using a region growing concept, the texture is analyzed for immutable shore and dynamic water areas. Finally, the prevalent shore line is examined by the resultant shapes. For method validation, various study areas are observed from several distances covering urban and rural flowing waters with different characteristics. Future work provides a transformation of the water line into object space by image-to-geometry intersection.

  4. Time-lapse video microscopy and image analysis of adherence and growth patterns of Candida albicans strains.

    Science.gov (United States)

    Nagy, Gabor; Hennig, Grant W; Petrenyi, Katalin; Kovacs, Laszlo; Pocsi, Istvan; Dombradi, Viktor; Banfalvi, Gaspar

    2014-06-01

    Digital image analysis of high time resolution video microscopy was used to investigate hyphal growth dynamics in different Candida albicans strains. The effects of the quorum sensing molecules tyrosol and farnesol, the deletion of the fungus specific protein phosphatase Z1 CaPPZ1), and the hypha-specific cyclin (HGC1) genes were analyzed by this method. Our system monitored cell growth in a CO2 incubator under near-physiological conditions and measured three major parameters under the following stringent conditions: (a) the time of yeast cell adherence, (b) the time of hyphal outgrowth, and (c) the rate of hyphal growth. This method showed that hyphal extension of wild-type SC5314 cells was accelerated by tyrosol and inhibited by farnesol. Hyphal growth rate was moderately lower in cappz1 and strongly reduced in hgc1 mutants. In addition, tyrosol treatment caused a firm adherence, while farnesol treatment and hgc1 mutation prevented the adherence of yeast cells to the surface of the culture flask. Transition from yeast-to-hyphal state was faster after tyrosol treatment, while it was reduced in farnesol-treated cells as well as in the cappz1 and hgc1 mutants. Our data confirm the notion that the attachment of yeast cells, the yeast-to-hyphal transition, and hyphal growth rate are closely related processes. Time-lapse video microscopy combined with image analysis offers a convenient and reliable method of testing chemicals, including potential drug candidates, and genetic manipulations on the dynamic morphological changes in C. albicans strains.

  5. Single-cell time-lapse analysis of depletion of the universally conserved essential protein YgjD

    Directory of Open Access Journals (Sweden)

    Ackermann Martin

    2011-05-01

    Full Text Available Abstract Background The essential Escherichia coli gene ygjD belongs to a universally conserved group of genes whose function has been the focus of a number of recent studies. Here, we put ygjD under control of an inducible promoter, and used time-lapse microscopy and single cell analysis to investigate the phenotypic consequences of the depletion of YgjD protein from growing cells. Results We show that loss of YgjD leads to a marked decrease in cell size and termination of cell division. The transition towards smaller size occurs in a controlled manner: cell elongation and cell division remain coupled, but cell size at division decreases. We also find evidence that depletion of YgjD leads to the synthesis of the intracellular signaling molecule (pppGpp, inducing a cellular reaction resembling the stringent response. Concomitant deletion of the relA and spoT genes - leading to a strain that is uncapable of synthesizing (pppGpp - abrogates the decrease in cell size, but does not prevent termination of cell division upon YgjD depletion. Conclusions Depletion of YgjD protein from growing cells leads to a decrease in cell size that is contingent on (pppGpp, and to a termination of cell division. The combination of single-cell timelapse microscopy and statistical analysis can give detailed insights into the phenotypic consequences of the loss of essential genes, and can thus serve as a new tool to study the function of essential genes.

  6. Application of time-lapse ERT to Characterize Soil-Water-Disease Interactions of Citrus Orchard - Case Study

    Science.gov (United States)

    Peddinti, S. R.; Kbvn, D. P.; Ranjan, S.; Suradhaniwar, S.; J, P. A.; R M, G.

    2015-12-01

    Vidarbha region in Maharashtra, India (home for mandarin Orange) experience severe climatic uncertainties resulting in crop failure. Phytopthora are the soil-borne fungal species that accumulate in the presence of moisture, and attack the root / trunk system of Orange trees at any stage. A scientific understanding of soil-moisture-disease relations within the active root zone under different climatic, irrigation, and crop cycle conditions can help in practicing management activities for improved crop yield. In this study, we developed a protocol for performing 3-D time-lapse electrical resistivity tomography (ERT) at micro scale resolution to monitor the changes in resistivity distribution within the root zone of Orange trees. A total of 40 electrodes, forming a grid of 3.5 m x 2 m around each Orange tree were used in ERT survey with gradient and Wenner configurations. A laboratory test on un-disturbed soil samples of the region was performed to plot the variation of electrical conductivity with saturation. Curve fitting techniques were applied to get the modified Archie's model parameters. The calibrated model was further applied to generate the 3-D soil moisture profiles of the study area. The point estimates of soil moisture were validated using TDR probe measurements at 3 different depths (10, 20, and 40 cm) near to the root zone. In order to understand the effect of soil-water relations on plant-disease relations, we performed ERT analysis at two locations, one at healthy and other at Phytopthora affected Orange tree during the crop cycle, under dry and irrigated conditions. The degree to which an Orange tree is affected by Phytopthora under each condition is evaluated using 'grading scale' approach following visual inspection of the canopy features. Spatial-temporal distribution of moisture profiles is co-related with grading scales to comment on the effect of climatic and irrigation scenarios on the degree and intensity of crop disease caused by Phytopthora.

  7. Calibration of Seismic Attributes for Reservoir Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Wayne D. Pennington

    2002-09-29

    The project, "Calibration of Seismic Attributes for Reservoir Characterization," is now complete. Our original proposed scope of work included detailed analysis of seismic and other data from two to three hydrocarbon fields; we have analyzed data from four fields at this level of detail, two additional fields with less detail, and one other 2D seismic line used for experimentation. We also included time-lapse seismic data with ocean-bottom cable recordings in addition to the originally proposed static field data. A large number of publications and presentations have resulted from this work, inlcuding several that are in final stages of preparation or printing; one of these is a chapter on "Reservoir Geophysics" for the new Petroleum Engineering Handbook from the Society of Petroleum Engineers. Major results from this project include a new approach to evaluating seismic attributes in time-lapse monitoring studies, evaluation of pitfalls in the use of point-based measurements and facies classifications, novel applications of inversion results, improved methods of tying seismic data to the wellbore, and a comparison of methods used to detect pressure compartments. Some of the data sets used are in the public domain, allowing other investigators to test our techniques or to improve upon them using the same data. From the public-domain Stratton data set we have demonstrated that an apparent correlation between attributes derived along 'phantom' horizons are artifacts of isopach changes; only if the interpreter understands that the interpretation is based on this correlation with bed thickening or thinning, can reliable interpretations of channel horizons and facies be made. From the public-domain Boonsville data set we developed techniques to use conventional seismic attributes, including seismic facies generated under various neural network procedures, to subdivide regional facies determined from logs into productive and non-productive subfacies, and we

  8. CALIBRATION OF SEISMIC ATTRIBUTES FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Wayne D. Pennington; Horacio Acevedo; Aaron Green; Joshua Haataja; Shawn Len; Anastasia Minaeva; Deyi Xie

    2002-10-01

    The project, ''Calibration of Seismic Attributes for Reservoir Calibration,'' is now complete. Our original proposed scope of work included detailed analysis of seismic and other data from two to three hydrocarbon fields; we have analyzed data from four fields at this level of detail, two additional fields with less detail, and one other 2D seismic line used for experimentation. We also included time-lapse seismic data with ocean-bottom cable recordings in addition to the originally proposed static field data. A large number of publications and presentations have resulted from this work, including several that are in final stages of preparation or printing; one of these is a chapter on ''Reservoir Geophysics'' for the new Petroleum Engineering Handbook from the Society of Petroleum Engineers. Major results from this project include a new approach to evaluating seismic attributes in time-lapse monitoring studies, evaluation of pitfalls in the use of point-based measurements and facies classifications, novel applications of inversion results, improved methods of tying seismic data to the wellbore, and a comparison of methods used to detect pressure compartments. Some of the data sets used are in the public domain, allowing other investigators to test our techniques or to improve upon them using the same data. From the public-domain Stratton data set we have demonstrated that an apparent correlation between attributes derived along ''phantom'' horizons are artifacts of isopach changes; only if the interpreter understands that the interpretation is based on this correlation with bed thickening or thinning, can reliable interpretations of channel horizons and facies be made. From the public-domain Boonsville data set we developed techniques to use conventional seismic attributes, including seismic facies generated under various neural network procedures, to subdivide regional facies determined from logs into

  9. Seismic velocity model of the crust and upper mantle along profile PANCAKE across the Carpathians between the Pannonian Basin and the East European Craton

    DEFF Research Database (Denmark)

    Starostenko, V.; Janik, T.; Kolomiyets, K.

    2013-01-01

    Results are presented of a seismic wide-angle reflection/refraction survey along a profile between the Pannonian Basin (PB) and the East European Craton (EEC) called PANCAKE. The P- and S-wave velocity model derived can be divided into three sectors: the PB; the Carpathians, including the Transca......Results are presented of a seismic wide-angle reflection/refraction survey along a profile between the Pannonian Basin (PB) and the East European Craton (EEC) called PANCAKE. The P- and S-wave velocity model derived can be divided into three sectors: the PB; the Carpathians, including...... the Transcarpathian Depression and the Carpathian Foredeep; and the south-western part of the EEC, including the Trans European Suture Zone (TESZ). Seismic data support a robust model of the Vp velocity structure of the crust. In the PB, the 22-23km thick crust consists of a 2-5km thick sedimentary layer (Vp=2...... of the lower crust towards the Ukrainian Shield, where a high velocity lower crust (Vp>7.2km/s) is observed. Two low-velocity lenses in the upper crust of the EEC are interpreted beneath major sedimentary troughs (Lviv and Volyn-Podolsk). Mantle reflectors are observed at depths of ~45km and ~75km below the PB...

  10. Monitoring temporal variations of seismic properties of the crust induced by the 2013 Ruisui earthquake in eastern Taiwan from coda wave interferometry with ambient seismic and strain fields

    Science.gov (United States)

    Dai, W. P.; Hung, S. H.; Wu, S. M.; Hsu, Y. J.

    2017-12-01

    Owing to the rapid development in ambient noise seismology, time-lapse variations in delay time and waveform decorrelation of coda derived from noise cross correlation (NCF) have been proved very effective to monitor slight changes in seismic velocity and scattering properties of the crust induced by various loadings such as the earthquake and healing process. In this study, we employ coda wave interferometry to detect the crustal perturbations immediately preceding and following the 2013 Mw 6.2 Ruisui Earthquake which struck the northern segment of the Longitudinal Valley Fault in eastern Taiwan, a seismically very active thrust suture zone separating the Eurasian and Philippine Sea Plate. By comparing the pre- and post-event coda waves extracted from the auto- and cross-correlation functions (ACFs and CCFs) of ambient seismic and strain fields recorded by the seismometers and borehole strainmeters, respectively, in the vicinity of the source region, we present a strong case that not only coseismic velocity reduction but also preceding decorrelation of waveforms are explicitly revealed in both the seismic and strain CCFs filtered in the secondary microseism frequency band of 0.1-0.9 Hz. Such precursory signals susceptible to the scattering properties of the crust are more unequivocally identified in the coda retrieved from the strainmeter data, suggesting that the ambient strain field can act as a more sensible probe to detect tiny structural perturbations in the critically stressed fault zone at the verge of failure. In addition to coseismic velocity changes detected in both the seismic and strain NCFs, we find quasi-periodic velocity variations that only appear in the strain retrieved coda signals, with a predominant cycle of 3-4 months correlating with the groundwater fluctuations observed at Ruisui.

  11. Modeling and inversion Matlab algorithms for resistivity, induced polarization and seismic data

    Science.gov (United States)

    Karaoulis, M.; Revil, A.; Minsley, B. J.; Werkema, D. D.

    2011-12-01

    M. Karaoulis (1), D.D. Werkema (3), A. Revil (1,2), A., B. Minsley (4), (1) Colorado School of Mines, Dept. of Geophysics, Golden, CO, USA. (2) ISTerre, CNRS, UMR 5559, Université de Savoie, Equipe Volcan, Le Bourget du Lac, France. (3) U.S. EPA, ORD, NERL, ESD, CMB, Las Vegas, Nevada, USA . (4) USGS, Federal Center, Lakewood, 10, 80225-0046, CO. Abstract We propose 2D and 3D forward modeling and inversion package for DC resistivity, time domain induced polarization (IP), frequency-domain IP, and seismic refraction data. For the resistivity and IP case, discretization is based on rectangular cells, where each cell has as unknown resistivity in the case of DC modelling, resistivity and chargeability in the time domain IP modelling, and complex resistivity in the spectral IP modelling. The governing partial-differential equations are solved with the finite element method, which can be applied to both real and complex variables that are solved for. For the seismic case, forward modeling is based on solving the eikonal equation using a second-order fast marching method. The wavepaths are materialized by Fresnel volumes rather than by conventional rays. This approach accounts for complicated velocity models and is advantageous because it considers frequency effects on the velocity resolution. The inversion can accommodate data at a single time step, or as a time-lapse dataset if the geophysical data are gathered for monitoring purposes. The aim of time-lapse inversion is to find the change in the velocities or resistivities of each model cell as a function of time. Different time-lapse algorithms can be applied such as independent inversion, difference inversion, 4D inversion, and 4D active time constraint inversion. The forward algorithms are benchmarked against analytical solutions and inversion results are compared with existing ones. The algorithms are packaged as Matlab codes with a simple Graphical User Interface. Although the code is parallelized for multi

  12. Quantitative high-resolution observations of soil water dynamics in a complicated architecture with time-lapse Ground-Penetrating Radar

    OpenAIRE

    P. Klenk; S. Jaumann; K. Roth

    2014-01-01

    High-resolution time-lapse Ground-Penetrating Radar (GPR) observations of advancing and retreating water tables can yield a wealth of information about near-surface water content dynamics. In this study, we present and analyze a series of imbibition, drainage and infiltration experiments which have been carried out at our artificial ASSESS test site and observed with surface based GPR. The test site features a complicated but known subsurface architecture co...

  13. In situ monitoring of corrosion mechanisms and phosphate inhibitor surface deposition during corrosion of zinc-magnesium-aluminium (ZMA) alloys using novel time-lapse microscopy.

    Science.gov (United States)

    Sullivan, James; Cooze, Nathan; Gallagher, Callum; Lewis, Tom; Prosek, Tomas; Thierry, Dominique

    2015-01-01

    In situ time-lapse optical microscopy was used to examine the microstructural corrosion mechanisms in three zinc-magnesium-aluminium (ZMA) alloy coated steels immersed in 1% NaCl pH 7. Preferential corrosion of MgZn(2) lamellae within the eutectic phases was observed in all the ZMA alloys followed by subsequent dissolution of Zn rich phases. The total extent and rate of corrosion, measured using time-lapse image analysis and scanning vibrating electrode technique (SVET) estimated mass loss, decreased as Mg and Al alloying additions were increased up to a level of 3 wt% Mg and 3.7 wt% Al. This was probably due to the increased presence of MgO and Al(2)O(3) at the alloy surface retarding the kinetics of cathodic oxygen reduction. The addition of 1 × 10(-2) mol dm(-3) Na(3)PO(4) to 1% NaCl pH 7 had a dramatic influence on the corrosion mechanism for a ZMA with passivation of anodic sites through phosphate precipitation observed using time-lapse image analysis. Intriguing rapid precipitation of filamentous phosphate was also observed and it is postulated that these filaments nucleate and grow due to super saturation effects. Polarisation experiments showed that the addition of 1 × 10(-2) mol dm(-3) Na(3)PO(4) to the 1% NaCl electrolyte promoted an anodic shift of 50 mV in open circuit potential for the ZMA alloy with a reduction in anodic current of 2.5 orders of magnitude suggesting that it was acting primarily as an anodic inhibitor supporting the inferences from the time-lapse investigations. These phosphate additions resulted in a 98% reduction in estimated mass loss as measured by SVET demonstrating the effectiveness of phosphate inhibitors for this alloy system.

  14. Degree of serpentinization in the forearc mantle wedge of Kyushu subduction zone: quantitative evaluations from seismic velocity

    Science.gov (United States)

    Xia, Shaohong; Sun, Jinlong; Huang, Haibo

    2015-09-01

    Serpentinization is an important phenomenon for understanding the water cycle and geodynamics of subduction zones in the upper mantle. In this study, we evaluate quantitatively the degree of serpentinization using the seismic velocity. The results show that serpentinization mainly occurs in the forearc mantle wedge along the subducted oceanic crust, and the degree of serpentinization in the forearc mantle wedge of Kyushu is strongly heterogeneous and varies from 0 to 12 %, containing about 0-1.8 % water contents. In general, the degree of serpentinization gradually decreases with depth from 40 to 80 km and the largest degree usually occur in about 40-50 km depth. Localized high anomalies of serpentinization are revealed in the northern and southern portions of Kyushu, respectively. We suggest that in the northern portion of the forearc mantle wedge, the water contents are relatively large, which might result from the abundant fractures and cracks with more fluids in the subducting slab because of the subduction of Kyushu-Palau ridge and the sudden change in its subduction angle of Philippine Sea lithosphere. But the high degree of serpentinization in the southern portion is closely associated with the active left-lateral shear zone revealed by global positioning system site velocities and earthquake focal mechanisms. In addition, the present results also display that the low degree of serpentinization in the central domain of the forearc mantle wedge is consistent with the location of anomalous arc volcano. The distribution of water contents is closely associated with the degree of serpentinization in the forearc mantle wedge.

  15. Mantle viscosity structure constrained by joint inversions of seismic velocities and density

    Science.gov (United States)

    Rudolph, M. L.; Moulik, P.; Lekic, V.

    2017-12-01

    The viscosity structure of Earth's deep mantle affects the thermal evolution of Earth, the ascent of mantle upwellings, sinking of subducted oceanic lithosphere, and the mixing of compositional heterogeneities in the mantle. Modeling the long-wavelength dynamic geoid allows us to constrain the radial viscosity profile of the mantle. Typically, in inversions for the mantle viscosity structure, wavespeed variations are mapped into density variations using a constant- or depth-dependent scaling factor. Here, we use a newly developed joint model of anisotropic Vs, Vp, density and transition zone topographies to generate a suite of solutions for the mantle viscosity structure directly from the seismologically constrained density structure. The density structure used to drive our forward models includes contributions from both thermal and compositional variations, including important contributions from compositionally dense material in the Large Low Velocity Provinces at the base of the mantle. These compositional variations have been neglected in the forward models used in most previous inversions and have the potential to significantly affect large-scale flow and thus the inferred viscosity structure. We use a transdimensional, hierarchical, Bayesian approach to solve the inverse problem, and our solutions for viscosity structure include an increase in viscosity below the base of the transition zone, in the shallow lower mantle. Using geoid dynamic response functions and an analysis of the correlation between the observed geoid and mantle structure, we demonstrate the underlying reason for this inference. Finally, we present a new family of solutions in which the data uncertainty is accounted for using covariance matrices associated with the mantle structure models.

  16. Temporal velocity variations beneath the Coso geothermal field observed using seismic double difference tomography of compressional and shear wave arrival times

    Science.gov (United States)

    Seher, T.; Zhang, H.; Fehler, M. C.; Newman, G. A.

    2011-12-01

    Microseismic imaging can be an important tool for characterizing geothermal reservoirs. Since microseismic sources occur more or less continuously due to the operations of a geothermal plant and the naturally occurring background seismicity, passive seismic monitoring is well suited for quantifying the temporal variations in reservoir properties that occur within the geothermal reservoir during production. In this study we will use microseismic data recorded between 1996 and 2008 to investigate the temporal variations in seismic velocity below the Coso geothermal field in California. In this study we will apply the double difference tomography method to simultaneously locate a suite of microseismic events and determine the compressional and shear wave velocity as well as their ratio. The double-difference method uses both absolute and relative arrival times of earthquakes measured at the same station, which allows a more precise determination of the relative locations of earthquakes. In particular, we apply a cross-correlation technique to improve the measurement of relative traveltimes. The large number of microearthquakes observed between 1996 and 2008 allows us to characterize subsurface velocity and to investigate changes in velocity that accompany production from the geothermal reservoir.

  17. Traveltime and waveform tomography analysis of synthetic borehole seismic data based on the CO2SINK project site, Germany

    Science.gov (United States)

    Yang, Can; Fan, Wenfang; Juhlin, Christopher

    2010-05-01

    Time lapse analysis of seismic data is very important for CO2 storage projects. Therefore, we have tested traveltime and waveform tomography methods to detect velocity changes in a CO2 injection reservoir using synthetic time lapse data. The structural model tested is based on the CO2SINK injection site at Ketzin, Germany where CO2 is being injected at about 630-650 m into a saline aquifer. First, we created synthetic time lapse moving source profiling (MSP) data, also known as walkaway profiling. The velocity model used for modeling was based on well logging and lithological information in the injection borehole. Gassmann fluid substitution was used to calculate the reservoir velocity after injection. In this substitution, we assumed a saturation of CO2 of 30%. The model velocity of the reservoir changed from 2750 m/s (before injection) to 2150 m/s (after injection). A 2D finite difference code available in Seismic Unix (www.cwp.mines.edu) was used. 60 source points were distributed along a surface line. The distance from the injection well was between 150m and 858m, with an interval of 12m. We recorded 21 channels at receiver depths from 470m to 670m, with an interval of 10m. The injection layer was assumed to be between 629m and 650m depth. The wavelet used for the synthetic data was a Gaussian derivative with an average frequency of 60Hz. Then first arrivals were picked on both data sets and used as input data for traveltime tomography. For traveltime tomography, the PS_tomo program was used. Since no data were recorded above 470m, the initial velocity model used above this depth was the true velocity model. Below 470m, the initial velocity model increases linearly from 3000m/s to 3250m/s. After inversion, the reservoir velocity and an anhydrite layer (high velocity layer) can be seen clearly in the final inverted velocity models. Using these velocity models as starting models, we performed waveform tomography in the frequency domain using a program supplied by

  18. Probing dynamic hydrologic system of slowly-creeping landslides with passive seismic imaging: A comprehensive landslide monitoring site at Lantai, Ilan area in Taiwan

    Science.gov (United States)

    Huang, H. H.; Hsu, Y. J.; Kuo, C. Y.; Chen, C. C.; Kuo, L. W.; Chen, R. F.; Lin, C. R.; Lin, P. P.; Lin, C. W.; Lin, M. L.; Wang, K. L.

    2017-12-01

    A unique landslide monitoring project integrating multidisciplinary geophysics experiments such as GPS, inclinometer, piezometer, and spontaneous potential log has been established at Lantai, Ilan area to investigating the possible detachment depth range and the physical mechanism of a slowly creeping landslide. In parallel with this, a lately deployed local seismic network also lends an opportunity to employ the passive seismic imaging technique to detect the time-lapse changes of seismic velocity in and around the landslide area. Such technique that retrieves Green's functions by cross-correlation of continuous ambient noise has opened new opportunities to seismologically monitoring the environmental and tectonic events such as ground water variation, magma intrusion under volcanos, and co-seismic medium damage in recent years. Integrating these geophysical observations, we explore the primary controls of derived seismic velocity changes and especially the hydrological response of the landslide to the passage of Megi typhoon in the last September 2016, which could potentially further our understanding of the dynamic system of landslides and in turn help the hazard mitigation.

  19. New tomographic images of P- , S- wave velocity and Q on the Philippine Sea Slab beneath Tokyo: Implication to seismotectonics and seismic hazard in the Tokyo metropolitan region

    Science.gov (United States)

    Hirata, Naoshi; Sakai, Shin'ichi; Nakagawa, Shigeki; Panayotopoulos, Yannis; Ishikawa, Masahiro; Sato, Hiroshi; Kasahara, Keiji; Kimura, Hisanor; Honda, Ryou

    2013-04-01

    The Central Disaster Management Council of Japan estimates the next great M7+ earthquake in the Tokyo metropolitan region will cause 11,000 fatalities and 112 trillion yen (1 trillion US) economic loss at worst case if it occur beneath northern Tokyo bay with M7.3. However, the estimate is based on a source fault model by conventional studies about the PSP geometry. To evaluate seismic hazard due to the great quake we need to clarify the geometry of PSP and also the Pacific palate (PAP) that subducs beneath PSP. We identify those plates with use of seismic tomography and available deep seismic reflection profiling and borehole data in southern Kanto area. We deployed about 300 seismic stations in the greater Tokyo urban region under the Special Project for Earthquake Disaster Mitigation in Tokyo Metropolitan Area. We obtain clear P- and S- wave velocity (Vp and Vs) and Q tomograms which show a clear image of PSP and PAP. A depth to the top of PSP, 20 to 30 kilometer beneath northern part of Tokyo bay, is about 10 km shallower than previous estimates based on the distribution of seismicity (Ishida, 1992). This shallower plate geometry changes estimations of strong ground motion for seismic hazards analysis within the Tokyo region. Based on elastic wave velocities of rocks and minerals, we interpreted the tomographic images as petrologic images. Tomographic images revealed the presence of two stepwise velocity increase of the top layer of the subducting PSP slab. Rock velocity data reveals that subducting PSP crust transforms from blueschists to amphibolites at depth of 30km and amphibolites to eclogites at depth of 50km, which suggest that dehydration reactions occurs in subducting crust of basaltic compositions during prograde metamorphism and water is released from the subducting PSP crust. Tomograms show evidence for a low-velocity zone (LVZ) beneath the area just north of Tokyo bay. A Q tomogram show a low Q zone in PSP slab. We interpret the LVZ as a

  20. Seismic Velocity/Temperature Correlations and a Possible New Geothermometer: Insights from Exploration of a High-Temperature Geothermal System on Montserrat, West Indies

    Directory of Open Access Journals (Sweden)

    Graham Alexander Ryan

    2014-10-01

    Full Text Available In 2013, two production wells were drilled into a geothermal reservoir on Montserrat, W.I. (West Indies Drilling results confirmed the main features of a previously developed conceptual model. The results confirm that below ~220 °C there is a negative correlation between reservoir temperature and seismic velocity anomaly. However, above ~220 °C there is a positive correlation. We hypothesise that anomalous variations in seismic velocity within the reservoir are controlled to first order by the hydrothermal mineral assemblage. This study suggests a new geophysical thermometer which can be used to estimate temperatures in three dimensions with unprecedented resolution and to indicate the subsurface fluid pathways which are the target of geothermal exploitation.

  1. Seismic velocity model of the central United States (Version 1): Description and simulation of the 18 April 2008 Mt. Carmel, Illinois, Earthquake

    Science.gov (United States)

    Ramírez‐Guzmán, Leonardo; Boyd, Oliver S.; Hartzell, Stephen; Williams, Robert A.

    2012-01-01

    We have developed a new three‐dimensional seismic velocity model of the central United States (CUSVM) that includes the New Madrid Seismic Zone (NMSZ) and covers parts of Arkansas, Mississippi, Alabama, Illinois, Missouri, Kentucky, and Tennessee. The model represents a compilation of decades of crustal research consisting of seismic, aeromagnetic, and gravity profiles; geologic mapping; geophysical and geological borehole logs; and inversions of the regional seismic properties. The density, P‐ and S‐wave velocities are synthesized in a stand‐alone spatial database that can be queried to generate the required input for numerical seismic‐wave propagation simulations. We test and calibrate the CUSVM by simulating ground motions of the 18 April 2008 Mw 5.4 Mt. Carmel, Illinois, earthquake and comparing the results with observed records within the model area. The selected stations in the comparisons reflect different geological site conditions and cover distances ranging from 10 to 430 km from the epicenter. The results, based on a qualitative and quantitative goodness‐of‐fit (GOF) characterization, indicate that both within and outside the Mississippi Embayment the CUSVM reasonably reproduces: (1) the body and surface‐wave arrival times and (2) the observed regional variations in ground‐motion amplitude, cumulative energy, duration, and frequency content up to a frequency of 1.0 Hz. In addition, we discuss the probable structural causes for the ground‐motion patterns in the central United States that we observed in the recorded motions of the 18 April Mt. Carmel earthquake.

  2. Two types of SDR recognised in pre-stack velocity analysis of ultra-long-offset seismic reflection data in the South Atlantic

    Science.gov (United States)

    Collier, J.; McDermott, C.; Lonergan, L.; McDermott, K.; Bellingham, P.

    2017-12-01

    Our understanding of continental breakup at volcanic margins has lagged behind that of non-volcanic margins in recent years. This is largely due to seismic imaging problems caused by the presence of thick packages of Seaward-Dipping Reflectors (SDRs) in the continent-ocean transition zone. These packages consist of interbedded tholeiitic lava flows, volcanic tuffs and terrestrial sediment that results in scattering, peg-leg multiples and defocusing of seismic energy. Here we analyse three ultra-long-offset (10.2 km), wide-bandwidth (5-100 Hz) seismic reflection profiles acquired by ION-GXT offshore South America during 2009-12 to gain new insights into the velocity structure of the SDRs and hence pattern of magmatism during continental breakup. We observe two seismic velocity patterns within the SDRs. The most landward packages show high velocity anomaly "bulls-eyes" of up to 1 km s-1. These highs occur where the stacked section shows them to thicken at the down-dip end of individual packages that are bounded by faults. All lines show 5-6 velocity highs spaced approximately 10 km apart. We interpret the velocity bulls-eyes as depleted mafic or ultramafic bodies that fed the sub-aerial tholeiitic lava flows during continental stretching. Similar relationships have been observed in outcrop onshore but have not been previously demonstrated in seismic data. The bulls-eye packages pass laterally into SDR packages that show no velocity highs. These packages are not associated with faulting and become more extensive going north towards the impact point of the Tristan da Cunha hotspot. This second type of SDR coincides with linear magnetic anomalies. We interpret these SDRs as the products of sub-aerial oceanic spreading similar to those seen on Iceland and described in the classic "Hinz model" and marine geophysical literature. Our work demonstrates that these SDRs are preceded by ones generated during an earlier phase of mechanical thinning of the continental crust. The

  3. Preliminary 3D P-wave Seismic Velocity Structure in the Rupture Zone of the April 1, 2014 Pisagua, Chile Earthquake from Controlled Source Data

    Science.gov (United States)

    Davenport, K. K.; Trehu, A. M.

    2017-12-01

    Variations in down-going slab morphology and geologic characteristics of the upper plate impact the evolution and seismic behavior of subduction zones during plate convergence. Disparities in strain accumulation, aseismic creep, earthquake slip rates, and segmentation of slip have all been connected to features such as subducting ridges and seamounts, large sedimentary basins on the forearc, and sediment thickness in the trench. Geologic features like these are associated with the rupture pattern of the Mw 8.2 April 1, 2014 Pisagua, Chile earthquake and its associated foreshocks and aftershocks. The 2014 events ruptured 200 km of a 500 km section where no significant seismicity had occurred since two M9 events in 1868 and 1877. The remaining un-ruptured region correlates with a high gravity anomaly in the forearc, suggesting that rupture propagation was controlled by geologic structure. To investigate these correlations, and provide insight into the relationship between geologic characteristics of the upper and lower plates and observed seismic behavior, the PICTURES (Pisagua/Iquique Crustal Tomography to Understand the Region of the Earthquake Source) project used the R/V Marcus Langseth to acquire a 3D controlled-source seismic experiment off the northern coast of Chile in 2016. The project included 45000 airgun shots recorded on short-period ocean bottom seismometers (OBS), an 8-12.5-km long streamer, and land-based stations. A 3D grid over the forearc allows high-resolution seismic imaging of the velocity and reflectivity structure in the region that ruptured during the 2014 Pisagua earthquake sequence. Here we present preliminary results from 3D tomography of travel times recorded at 70 OBS sites within the 3D grid. In-depth data analysis is ongoing to evaluate data quality and produce preliminary 2D velocity profiles in preparation for a full 3D inversion of primary and secondary arrivals. Ultimately the 3D velocity model will be integrated with multi

  4. Seismic velocity structure and spatial distribution of reflection intensity off the Boso Peninsula, Central Japan, revealed by an ocean bottom seismographic experiment

    Science.gov (United States)

    Kono, Akihiro; Sato, Toshinori; Shinohara, Masanao; Mochizuki, Kimihiro; Yamada, Tomoaki; Uehira, Kenji; Shinbo, Takashi; Machida, Yuuya; Hino, Ryota; Azuma, Ryosuke

    2016-04-01

    Off the Boso Peninsula, central Japan, where the Sagami Trough is in the south and the Japan Trench is in the east, there is a triple junction where the Pacific plate (PAC), the Philippine Sea plate (PHS) and the Honshu island arc (HIA) meet each other. In this region, the PAC subducts beneath the PHS and the HIA, and the PHS subducts beneath the HIA. Due to the subduction of 2 oceanic plates, numerous seismic events took place in the past. In order to understand these events, it is important to image structure of these plates. Hence, many researchers attempted to reveal the substructure from natural earthquakes and seismic experiments. Because most of the seismometers are placed inland area and the regular seismicity off Boso is inactive, it is difficult to reveal the precise substructure off Boso area using only natural earthquakes. Although several marine seismic experiments using active sources were conducted, vast area remains unclear off Boso Peninsula. In order to improve the situation, a marine seismic experiment, using airgun as an active source, was conducted from 30th July to 4th of August, 2009. The survey line has 216 km length and 20 Ocean Bottom Seismometers (OBSs) were placed on it. We estimated 2-D P-wave velocity structure from the airgun data using the PMDM (Progressive Model Development Method; Sato and Kenett, 2000) and the FAST (First Arrival Seismic Tomography ; Zelt and Barton, 1998). Furthermore, we identified the probable reflection phases from the data and estimated the location of reflectors using Travel time mapping method (Fujie et al. 2006). We found some reflection phases from the data, and the reflectors are located near the region where P-wave velocity is 5.0 km/s. We interpret that the reflectors indicate the plate boundary between the PHS and the HIA. The variation of the intensity of reflection along the upper surface of PHS seems to be consistent with the result from previous reflection seismic experiment conducted by Kimura et

  5. Estimation of soil hydraulic parameters in the field by integrated hydrogeophysical inversion of time-lapse ground-penetrating radar data

    KAUST Repository

    Jadoon, Khan

    2012-01-01

    An integrated hydrogeophysical inversion approach was used to remotely infer the unsaturated soil hydraulic parameters from time-lapse ground-penetrating radar (GPR) data collected at a fixed location over a bare agricultural field. The GPR model combines a full-waveform solution of Maxwell\\'s equations for three-dimensional wave propaga- tion in planar layered media together with global reflection and transmission functions to account for the antenna and its interactions with the medium. The hydrological simu- lator HYDRUS-1D was used with a two layer single- and dual-porosity model. The radar model was coupled to the hydrodynamic model, such that the soil electrical properties (permitivity and conductivity) that serve as input to the GPR model become a function of the hydrodynamic model output (water content), thereby permiting estimation of the soil hydraulic parameters from the GPR data in an inversion loop. To monitor the soil water con- tent dynamics, time-lapse GPR and time domain reflectometry (TDR) measurements were performed, whereby only GPR data was used in the inversion. Significant effects of water dynamics were observed in the time-lapse GPR data and in particular precipitation and evaporation events were clearly visible. The dual porosity model provided betier results compared to the single porosity model for describing the soil water dynamics, which is sup- ported by field observations of macropores. Furthermore, the GPR-derived water content profiles reconstructed from the integrated hydrogeophysical inversion were in good agree- ment with TDR observations. These results suggest that the proposed method is promising for non-invasive characterization of the shallow subsurface hydraulic properties and moni- toring water dynamics at the field scale. © Soil Science Society of America.

  6. Seismic Velocity Variation and Evolution of the Upper Oceanic Crust across the Mid-Atlantic Ridge at 1.3°S

    Science.gov (United States)

    Jian, H.; Singh, S. C.

    2017-12-01

    The oceanic crust that covers >70% of the solid earth is formed at mid-ocean ridges, but get modified as it ages. Understanding the evolution of oceanic crust requires investigations of crustal structures that extend from zero-age on the ridge axis to old crust. In this study, we analyze a part of a 2000-km-long seismic transect that crosses the Mid-Atlantic Ridge segment at 1.3°S, south of the Chain transform fault. The seismic data were acquired using a 12-km-long multi-sensor streamer and dense air-gun shots. Using a combination of downward continuation and seismic tomography methods, we have derived a high-resolution upper crustal velocity structure down to 2-2.5 km depth below the seafloor, from the ridge axis to 3.5 Ma on both sides of the ridge axis. The results demonstrate that velocities increase at all depths in the upper crust as the crust ages, suggesting that hydrothermal precipitations seal the upper crustal pore spaces. This effect is most significant in layer 2A, causing a velocity increase of 0.5-1 km/s after 1-1.5 Ma, beyond which the velocity increase is very small. Furthermore, the results exhibit a significant decrease in both the frequency and amplitude of the low-velocity anomalies associated with faults beyond 1-1.5 Ma, when faults become inactive, suggesting a linkage between the sealing of fault space and the extinction of hydrothermal activity. Besides, the off-axis velocities are systematically higher on the eastern side of the ridge axis compared to on the western side, suggesting that a higher hydrothermal activity should exist on the outside-corner ridge flank than on the inside-corner flank. While the tomography results shown here cover 0-3.5 Ma crust, the ongoing research will further extend the study area to older crust and also incorporating pre-stack migration and full waveform inversion methods to improve the seismic structure.

  7. Visualizing and quantifying movement from pre-recorded videos: The spectral time-lapse (STL algorithm [v1; ref status: indexed, http://f1000r.es/2qo

    Directory of Open Access Journals (Sweden)

    Christopher R Madan

    2014-01-01

    Full Text Available When studying animal behaviour within an open environment, movement-related data are often important for behavioural analyses. Therefore, simple and efficient techniques are needed to present and analyze the data of such movements. However, it is challenging to present both spatial and temporal information of movements within a two-dimensional image representation. To address this challenge, we developed the spectral time-lapse (STL algorithm that re-codes an animal’s position at every time point with a time-specific color, and overlays it with a reference frame of the video, to produce a summary image. We additionally incorporated automated motion tracking, such that the animal’s position can be extracted and summary statistics such as path length and duration can be calculated, as well as instantaneous velocity and acceleration. Here we describe the STL algorithm and offer a freely available MATLAB toolbox that implements the algorithm and allows for a large degree of end-user control and flexibility.

  8. Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment

    Science.gov (United States)

    Ayarza, P.; Carbonell, R.; Teixell, A.; Palomeras, I.; Martí, D.; Kchikach, A.; Harnafi, M.; Levander, A.; Gallart, J.; Arboleya, M. L.; Alcalde, J.; Fernández, M.; Charroud, M.; Amrhar, M.

    2014-05-01

    The crustal structure and topography of the Moho boundary beneath the Atlas Mountains of Morocco has been constrained by a controlled source, wide-angle seismic reflection transect: the SIMA experiment. This paper presents the first results of this project, consisting of an almost 700 km long, high-resolution seismic profile acquired from the Sahara craton across the High and the Middle Atlas and the Rif Mountains. The interpretation of this seismic data set is based on forward modeling by raytracing, and has resulted in a detailed crustal structure and velocity model for the Atlas Mountains. Results indicate that the High Atlas features a moderate crustal thickness, with the Moho located at a minimum depth of 35 km to the S and at around 31 km to the N, in the Middle Atlas. Upper crustal shortening is resolved at depth through a crustal root where the Saharan crust underthrusts the northern Moroccan crust. This feature defines a lower crust imbrication that, locally, places the Moho boundary at ˜40-41 km depth in the northern part of the High Atlas. The P-wave velocity model is characterized by relatively low velocities, mostly in the lower crust and upper mantle, when compared to other active orogens and continental regions. These low deep crustal velocities together with other geophysical observables such as conductivity estimates derived from MT measurements, moderate Bouguer gravity anomaly, high heat flow, and surface exposures of recent alkaline volcanism lead to a model where partial melts are currently emplaced at deep crustal levels and in the upper mantle. The resulting model supports the existence of a mantle upwelling as mechanism that would contribute significantly to sustain the High Atlas topography. However, the detailed Moho geometry deduced in this work should lead to a revision of the exact geometry and position of this mantle feature and will require new modeling efforts.

  9. Final Report: Improved Site Characterization And Storage Prediction Through Stochastic Inversion Of Time-Lapse Geophysical And Geochemical Data

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, A; Mcnab, W; Hao, Y; White, D; Johnson, J

    2011-04-14

    During the last months of this project, our project activities have concentrated on four areas: (1) performing a stochastic inversion of pattern 16 seismic data to deduce reservoir bulk/shear moduli and density; the need for this inversion was not anticipated in the original scope of work, (2) performing a stochastic inversion of pattern 16 seismic data to deduce reservoir porosity and permeability, (3) complete the software needed to perform geochemical inversions and (4) use the software to perform stochastic inversion of aqueous chemistry data to deduce mineral volume fractions. This report builds on work described in progress reports previously submitted (Ramirez et al., 2009, 2010, 2011 - reports fulfilled the requirements of deliverables D1-D4) and fulfills deliverable D5: Field-based single-pattern simulations work product. The main challenge with our stochastic inversion approach is its large computational expense, even for single reservoir patterns. We dedicated a significant level of effort to improve computational efficiency but inversions involving multiple patterns were still intractable by project's end. As a result, we were unable to fulfill Deliverable D6: Field-based multi-pattern simulations work product.

  10. Multi-scale mantle structure underneath the Americas from a new tomographic model of seismic shear velocity

    Science.gov (United States)

    Porritt, R. W.; Becker, T. W.; Auer, L.; Boschi, L.

    2017-12-01

    We present a whole-mantle, variable resolution, shear-wave tomography model based on newly available and existing seismological datasets including regional body-wave delay times and multi-mode Rayleigh and Love wave phase delays. Our body wave dataset includes 160,000 S wave delays used in the DNA13 regional tomographic model focused on the western and central US, 86,000 S and SKS delays measured on stations in western South America (Porritt et al., in prep), and 3,900,000 S+ phases measured by correlation between data observed at stations in the IRIS global networks (IU, II) and stations in the continuous US, against synthetic data generated with IRIS Syngine. The surface wave dataset includes fundamental mode and overtone Rayleigh wave data from Schaeffer and Levedev (2014), ambient noise derived Rayleigh wave and Love wave measurements from Ekstrom (2013), newly computed fundamental mode ambient noise Rayleigh wave phase delays for the continuous US up to July 2017, and other, previously published, measurements. These datasets, along with a data-adaptive parameterization utilized for the SAVANI model (Auer et al., 2014), should allow significantly finer-scale imaging than previous global models, rivaling that of regional-scale approaches, under the USArray footprint in the continuous US, while seamlessly integrating into a global model. We parameterize the model for both vertically (vSV) and horizontally (vSH) polarized shear velocities by accounting for the different sensitivities of the various phases and wave types. The resulting, radially anisotropic model should allow for a range of new geodynamic analysis, including estimates of mantle flow induced topography or seismic anisotropy, without generating artifacts due to edge effects, or requiring assumptions about the structure of the region outside the well resolved model space. Our model shows a number of features, including indications of the effects of edge-driven convection in the Cordillera and along

  11. Along-Strike Differences of the Main Himalayan Thrust and Deformation within the Indian Crust: Insights from Seismicity and Seismic Velocities in Bhutan and its Foreland

    Science.gov (United States)

    Diehl, T.; Singer, J.; Hetényi, G.; Kissling, E. H.; Clinton, J. F.

    2015-12-01

    The seismicity of Bhutan is characterized by the apparent lack of great earthquakes and a significantly lower activity compared to most other parts of the Himalayan arc. To better understand the underlying mechanisms of this anomalously low activity and to relate it with possible along-strike differences in the structure of the orogenic belt, a temporary network with up to 38 broadband seismometers was installed in Bhutan between January 2013 and November 2014. In this work we present a catalog of local and regional earthquakes detected and located with the GANSSER network complemented by regional stations in India, Bangladesh, and China. State-of-the-art data analysis and earthquake location procedures were applied to derive a high-precision earthquake catalog of Bhutan and surrounding regions. Focal mechanisms from regional moment tensor inversions and first-motion polarities complement the earthquake catalog. In the vicinity of the Shumar-Kuru Chu Spur in East Bhutan, seismicity forms a moderately dipping structure at about 12 km depth, which we associate with the Main Himalayan Thrust (MHT). North of 27.6°N the dip of the structure steepens, which can be interpreted as a ramp along the MHT. In West Bhutan seismicity occurs at depths of 20 to 40 km and receiver function images indicate that seismicity occurs in the underthrusting Indian crust rather than on the MHT. The highest seismic activity is clustered along the Goalpara Lineament, a dextral NE-SW striking shear zone in southwest Bhutan, which appears to connect to the western edge of the Shillong Plateau in the foreland. Focal depths indicate that this shear zone is located at depths of 20-30 km and therefore in the underthrusting Indian crust. Preliminary results of a 3D local earthquake tomography show substantial differences in the uppermost crust between east and west Bhutan. Consistent with our receiver function images, the results also indicate a thinning of the crustal root towards eastern Bhutan.

  12. Combination of metabolism measurement and a time-lapse system provides an embryo selection method based on oxygen uptake and chronology of cytokinesis timing.

    Science.gov (United States)

    Tejera, Alberto; Castelló, Damia; de Los Santos, Jose Maria; Pellicer, Antonio; Remohí, Jose; Meseguer, Marcos

    2016-07-01

    To evaluate correlations between oxygen consumption (OC) measurements before and after embryo cytokinesis, observing OC during embryo cleavages and combining that information with morphokinetics to relate to implantation potential. Prospective cohort study. University-affiliated private IVF unit. A total of 1,150 injected oocytes in 86 first oocyte donation cycles with embryo transfer on day 3. None. We analyzed the embryo OC and combined this data with the cytokinesis event, exact timing (in hours) of blastomeric cleavages, with the use of an incubator equipped with time-lapse videography, gathering a total of 7,630 measurements during the cytokinesis (active phase) and consecutive measurements after this division (passive phase), correlating this data with embryo outcome. OC was found to increase during embryo cleavage, showing high levels during first division with a strong correlation with implantation success. Moreover, those embryos with slow or fast development gave rise to lower OC levels, whereas higher levels were associated with optimal embryo division ranges linked to higher implantation potential. A detailed analysis of OC by time-lapse observations enhances the value that these measurements represented as markers of embryo quality, especially during the cytokinesis events produced during preimplantation development. Copyright © 2016. Published by Elsevier Inc.

  13. Simultaneous Gram and viability staining on activated sludge exposed to erythromycin: 3D CLSM time-lapse imaging of bacterial disintegration.

    Science.gov (United States)

    Louvet, Jean-Noël; Attik, Ghania; Dumas, Dominique; Potier, Olivier; Pons, Marie-Noëlle

    2011-11-01

    The effect of erythromycin on activated sludge bacteria according to their Gram type was investigated with 3-dimensional Confocal Laser Scanning Microscopy (CLSM) time-lapse imaging. The fluorescent stains SYTOX Green and Texas Red-X conjugate of wheat germ agglutinin stained dying bacteria and Gram(+) bacteria respectively. Time-lapse imaging allowed an understanding of the staining mechanism and the measurement of the death rate. In presence of erythromycin (10mg/L), Gram(+) bacteria had a higher mortality rate than the Gram(-) bacteria. This result suggests that antibiotic in wastewater could change the activated sludge bacteria composition, according to their Gram type by selecting the bacteria which are the least sensitive to the antibiotics. However bacterial death was followed by bacterial disintegration leading to a decrease in the fluorescence. Results suggested that the viability indicators based on membrane integrity should be used with a correct sampling method, which can give the initial quantity of living bacteria. Copyright © 2011 Elsevier GmbH. All rights reserved.

  14. Assessment of human embryo development using morphological criteria in an era of time-lapse, algorithms and 'OMICS': is looking good still important?

    Science.gov (United States)

    Gardner, David K; Balaban, Basak

    2016-10-01

    With the worldwide move towards single embryo transfer there has been a renewed focus on the requirement for reliable means of assessing embryo viability. In an era of 'OMICS' technologies, and algorithms created through the use of time-lapse microscopy, the actual appearance of the human embryo as it progresses through each successive developmental stage to the blastocyst appears to have been somewhat neglected in recent years. Here we review the key features of the human preimplantation embryo and consider the relationship between morphological characteristics and developmental potential. Further, the impact of the culture environment on morphological traits, how key morphological qualities reflect aspects of embryo physiology, and how computer-assisted analysis of embryo morphology may facilitate a more quantitative approach to selection are discussed. The clinical introduction of time-lapse systems has reopened our eyes and given us a new vantage point from which to view the beauty of the initial stages of human life. Rather than a future in which the morphology of the embryo is deemed irrelevant, we propose that key features, such as multinucleation, cell size and blastocyst differentiation should be included in future iterations of selection/deselection algorithms. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved.For Permissions, please email: journals.permissions@oup.com.

  15. Time-lapse deselection model for human day 3 in vitro fertilization embryos: the combination of qualitative and quantitative measures of embryo growth.

    Science.gov (United States)

    Liu, Yanhe; Chapple, Vincent; Feenan, Katie; Roberts, Peter; Matson, Phillip

    2016-03-01

    To present a time-lapse deselection model involving both qualitative and quantitative parameters for assessing embryos on day 3. Retrospective cohort study and prospective validation. Private IVF center. A total of 270 embryos with known implantation data (KID) after day 3 transfer from 212 IVF/intracytoplasmic sperm injection (ICSI) cycles were retrospectively analyzed for building the proposed deselection model, followed by prospective validation using an additional 66 KID embryos. None. Morphological score on day 3, embryo morphokinetic parameters, abnormal cleavage patterns, and known implantation results. All included embryos were categorized either retrospectively or prospectively into 7 grades (A+, A, B, C, D, E, F). Qualitative deselection parameters included poor conventional day 3 morphology, abnormal cleavage patterns identified via time-lapse monitoring, and deselection effectively predicts day 3 embryo implantation potential and is applicable to all IVF embryos regardless of insemination method by using PNF as the reference starting time point. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  16. Time-Lapse Analysis of Methane Quantity in the Mary Lee Group of Coal Seams Using Filter-Based Multiple-Point Geostatistical Simulation.

    Science.gov (United States)

    Karacan, C Özgen; Olea, Ricardo A

    2013-08-01

    Coal seam degasification and its success are important for controlling methane, and thus for the health and safety of coal miners. During the course of degasification, properties of coal seams change. Thus, the changes in coal reservoir conditions and in-place gas content as well as methane emission potential into mines should be evaluated by examining time-dependent changes and the presence of major heterogeneities and geological discontinuities in the field. In this work, time-lapsed reservoir and fluid storage properties of the New Castle coal seam, Mary Lee/Blue Creek seam, and Jagger seam of Black Warrior Basin, Alabama, were determined from gas and water production history matching and production forecasting of vertical degasification wellbores. These properties were combined with isotherm and other important data to compute gas-in-place (GIP) and its change with time at borehole locations. Time-lapsed training images (TIs) of GIP and GIP difference corresponding to each coal and date were generated by using these point-wise data and Voronoi decomposition on the TI grid, which included faults as discontinuities for expansion of Voronoi regions. Filter-based multiple-point geostatistical simulations, which were preferred in this study due to anisotropies and discontinuities in the area, were used to predict time-lapsed GIP distributions within the study area. Performed simulations were used for mapping spatial time-lapsed methane quantities as well as their uncertainties within the study area. The systematic approach presented in this paper is the first time in literature that history matching, TIs of GIPs and filter simulations are used for degasification performance evaluation and for assessing GIP for mining safety. Results from this study showed that using production history matching of coalbed methane wells to determine time-lapsed reservoir data could be used to compute spatial GIP and representative GIP TIs generated through Voronoi decomposition

  17. Seismic velocities - density relationship for the Earth's crust: effects of chemical compositions, amount of water, and implications on gravity and topography

    Science.gov (United States)

    Guerri, Mattia; Cammarano, Fabio

    2014-05-01

    Seismic velocities - density relationship for the Earth's crust: effects of chemical compositions, amount of water, and implications on gravity and topography Mattia Guerri and Fabio Cammarano Department of Geosciences and Natural Resource Management, Section of Geology, University of Copenhagen, Denmark. A good knowledge of the Earth's crust is not only important to understand its formation and dynamics, but also essential to infer mantle seismic structure, dynamic topography and location of seismic events. Global and local crustal models available (Bassin et al., 2000; Nataf & Ricard, 1996; Molinari & Morelli, 2011) are based on VP-density empirical relationships that do not fully exploit our knowledge on mineral phases forming crustal rocks and their compositions. We assess the effects of various average crustal chemical compositions on the conversion from seismic velocities to density, also testing the influence of water. We consider mineralogies at thermodynamic equilibrium and reference mineral assemblages at given P-T conditions to account for metastability. Stable mineral phases at equilibrium have been computed with the revised Holland and Powell (2002) EOS and thermodynamic database implemented in PerpleX (Connolly 2005). We have computed models of physical properties for the crust following two approaches, i) calculation of seismic velocities and density by assuming the same layers structure of the model CRUST 2.0 (Bassin et al., 2000) and a 3-D thermal structure based on heat-flow measurements; ii) interpretation of the Vp model reported in CRUST 2.0 to obtain density and shear wave velocity for the crustal layers, using the Vp-density relations obtained with the thermodynamic modeling. The obtained density models and CRUST 2.0 one have been used to calculate isostatic topography and gravity field. Our main results consist in, i) phase transitions have a strong effect on the physical properties of crustal rocks, in particular on seismic velocities; ii

  18. Seismic velocities within the sedimentary succession of the Canada Basin and southern Alpha-Mendeleev Ridge, Arctic Ocean: evidence for accelerated porosity reduction?

    Science.gov (United States)

    Shimeld, John; Li, Qingmou; Chian, Deping; Lebedeva-Ivanova, Nina; Jackson, Ruth; Mosher, David; Hutchinson, Deborah

    2016-01-01

    The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity-depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity-depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity-depth profiles for each seismic trace. A thickness of 12-13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity-depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares favourably with

  19. Seismic velocity anisotropy of phyllosilicate-rich rocks: characteristics inferred from experimental and crack-model studies of biotite-rich schist

    Science.gov (United States)

    Nishizawa, O.; Kanagawa, K.

    2010-07-01

    Seismic velocity anisotropy of biotite schist (30 per cent-mode biotite) was measured under confining pressures up to 150 MPa. The rock shows weak orthotropy which was altered from transverse isotropy (TI) generated by biotite-preferred orientation. The orthotropy was caused by microfolding in the rock. The velocity increase under confining pressure indicates that most crack planes are aligned parallel to the cleavage planes (silicate sheet) of the oriented biotite minerals. The anisotropy of the rock is basically TI due to both the aligned biotite minerals and cracks, which have a common symmetry axis. We found that other sheet silicate-rich rocks have a similar anisotropy with the biotite schist, in which the TI-type anisotropy is characterized by the slow P- and S-wave velocities along the symmetry axis. This is caused by the preferred orientation of sheet silicate minerals and the extremely slow P- and S-wave velocities along the axis perpendicular to the silicate sheet compared to the directions along the silicate sheet. When rock contains a large percentage of highly oriented sheet silicates, the fast and slow shear waves exchange their polarities at some off-symmetry axis directions, indicating that the qS-wave (quasi-S wave) velocity exceeds the SH-wave velocity. The phase velocity distribution of qS wave shows an asymmetry with respect to the angle from the symmetry axis, which is characterized by a bulge in this distribution located near the symmetric axis. This is inherent to most sheet silicate minerals. When crack density of aligned cracks increases, the P-wave velocity along the symmetry axis decreases considerably. The qS-wave phase velocity in the off-axis directions also decreases, in accordance with the decrease of the P velocity along the symmetry axis. The asymmetry of the qS-wave phase velocity distribution increases as the P-wave velocity decreases along the symmetry axis. This relationship can be well understood by means of Berryman

  20. Geophysical imaging of near-surface structure using electromagnetic and seismic waves

    Science.gov (United States)

    Chen, Yongping

    of tomograms to interpret plume morphology. In my second study I developed a passive-seismic method to image shear-wave velocity, which is an important geotechnical property commonly correlated with soil type or lithology. I inverted shear-wave velocity profiles from the phase velocity dispersion of Rayleigh waves based on passive seismic observations (microtremors). I used several sets of microtremor data which were collected at different sites. I obtained the phase velocity dispersion curve by the Extended Spatial Autocorrelation (ESPAC) method. I used simulated annealing method is used to invert the subsurface shear-wave velocity profile from the fundamental phase velocity dispersion curve. The field-experimental and synthetic results indicated that the microtremor approach can provide valuable information for quantitative geotechnical and hydrologic characterization. In my third study I developed a method to image vadose-zone dynamics using GPR. Flow in the unsaturated zone is important for predicting groundwater recharge, contaminant migration, and chemical/microbiological processes. However, it is difficult to characterize or monitor with conventional hydrologic measurements, which provide information at sparse locations. The purpose of this study was to image changes in moisture content, as well as aquifer structure based on the relation between dielectric constant and water content. The objective was to calibrate a flow model to field-experimental, time-lapse GPR data collected during an infiltration experiment. To this end, (1) I constructed a VS2DT model based on aquifer structure interpreted from static GPR reflection profiles; (2) I manually calibrated the model to reproduce observed changes in GPR data during infiltration; and (3) I used a time-domain electromagnetic finite-difference model to simulate experimental observations for comparison. The results of this work indicate that time-lapse GPR can monitor changes in water content on the order of a few

  1. Seismic site-response characterization of high-velocity sites using advanced geophysical techniques: application to the NAGRA-Net

    Czech Academy of Sciences Publication Activity Database

    Poggi, V.; Burjánek, Jan; Michel, C.; Fäh, D.

    2017-01-01

    Roč. 210, č. 2 (2017), s. 645-659 ISSN 0956-540X Institutional support: RVO:67985530 Keywords : joint inversion * earthquake ground motions * seismic noise * site effects Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Volcanology Impact factor: 2.414, year: 2016

  2. 2.5D seismic velocity modelling in the south-eastern Romanian Carpathians Orogen and its foreland.

    NARCIS (Netherlands)

    Bocin, A.; Stephenson, R.A.; Tryggvason, A.; Panea, I; Mocanu, V.I.; Hauser, F

    2005-01-01

    The DACIA-PLAN (Danube and Carpathian Integrated Action on Processes in the Lithosphere and Neotectonics) deep seismic reflection survey was performed in August-September 2001, with the objective of obtaining new information on the deep structure of the external Carpathians nappe system and the

  3. Time-lapse cinematography study of the germinal vesicle behaviour in mouse primary oocytes treated with activators of protein kinases A and C.

    Science.gov (United States)

    Alexandre, H; Mulnard, J

    1988-12-01

    A passive erratic movement of the germinal vesicle (GV), already visible in small incompetent oocytes, is followed by an active scalloping of the nuclear membrane soon before GV breakdown (GVBD) in cultured competent oocytes. Maturation can be inhibited by activators of protein kinase A (PK-A) and protein kinase C (PK-C). Our time-lapse cinematography analysis allowed us to describe an unexpected behaviour of the GV when PK-C, but not PK-A, is activated: GV undergoes a displacement toward the cortex according to the same biological clock which triggers the programmed translocation of the spindle in control oocytes. It is concluded that, when oocytes become committed to undergo maturation, the cytoplasm acquires a PK-A-controlled "centrifugal displacement property" which is not restricted to the spindle.

  4. Time lapse imaging analysis of the effect of ER stress modulators on apoptotic cell assessed by caspase3/7 activation in NG108-15 cells

    Directory of Open Access Journals (Sweden)

    Ayako Saito

    2016-03-01

    Full Text Available This paper reports the data from the long term time lapse imaging of neuronal cell line NG108-15 that were treated with apoptosis inducer or various ER stress inducers. Use of the fluorescent reporter for activated caspase3/7 in combination with the conventional light microscope allowed us to investigate the time course of apoptosis induction at the single cell level. Quantitative as well as qualitative data are presented here to show the effect of two different ER stress modulating chemical compounds on caspase3/7-dependent apoptosis in neuronal cell line NG108-15 cells. Additional results and interpretation of our data concerning ER stress and apoptosis in NG108-15 cells can be found in Suga et al. (2015 [1] and in Suga et al. (2015 [2].

  5. The type of GnRH analogue used during controlled ovarian stimulation influences early embryo developmental kinetics: a time-lapse study.

    Science.gov (United States)

    Muñoz, Manuel; Cruz, María; Humaidan, Peter; Garrido, Nicolás; Pérez-Cano, Inmaculada; Meseguer, Marcos

    2013-06-01

    To explore if the GnRH analogue used for controlled ovarian stimulation (COS) and the ovulation triggering factor (GnRH agonist + hCG triggering versus GnRH antagonist + GnRH agonist triggering) affect embryo development and kinetics. In a retrospective cohort study in the Instituto Valenciano de Infertilidad (IVI) Alicante and the Instituto Universitario-IVI Valencia, Spain, 2817 embryos deriving from 400 couples undergoing oocyte donation were analysed. After controlled ovarian stimulation and IVF/intracytoplamic sperm injection, the timing of embryonic cleavages was assessed by a video time-lapse system. The results were analysed using Student's t test for comparison of timings (hours) and Chi-squared test for comparison of proportions. A p-value we can suggest that the type of protocol used for controlled ovarian stimulation influences embryo kinetics of development but these variations are not reflected in embryo quality. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  6. Bayesian Markov-Chain-Monte-Carlo inversion of time-lapse crosshole GPR data to characterize the vadose zone at the Arrenaes Site, Denmark

    DEFF Research Database (Denmark)

    Scholer, Marie; Irving, James; Zibar, Majken Caroline Looms

    2012-01-01

    We examined to what extent time-lapse crosshole ground-penetrating radar traveltimes, measured during a forced infiltration experiment at the Arreneas field site in Denmark, could help to quantify vadose zone hydraulic properties and their corresponding uncertainties using a Bayesian Markov......-chain-Monte-Carlo inversion approach with different priors. The ground-penetrating radar (GPR) geophysical method has the potential to provide valuable information on the hydraulic properties of the vadose zone because of its strong sensitivity to soil water content. In particular, recent evidence has suggested...... in Denmark, could help to quantify VGM parameters and their uncertainties in a layered medium, as well as the corresponding soil hydraulic properties. We used a Bayesian Markov-chain-Monte-Carlo inversion approach. We first explored the advantages and limitations of this approach with regard to a realistic...

  7. Seismic history matching of fluid fronts using the ensemble kalman filter

    NARCIS (Netherlands)

    Trani, M.; Arts, R.; Leeuwenburgh, O.

    2013-01-01

    Time-lapse seismic data provide information on the dynamics of multiphase reservoir fluid flow in places where no production data from wells are available. This information, in principle, could be used to estimate unknown reservoir properties. However, the amount, resolution, and character of the

  8. Distance parameterization for efficient seismic history matching with the ensemble Kalman Filter

    NARCIS (Netherlands)

    Leeuwenburgh, O.; Arts, R.

    2012-01-01

    The Ensemble Kalman Filter (EnKF), in combination with travel-time parameterization, provides a robust and flexible method for quantitative multi-model history matching to time-lapse seismic data. A disadvantage of the parameterization in terms of travel-times is that it requires simulation of

  9. Noninferiority, randomized, controlled trial comparing embryo development using media developed for sequential or undisturbed culture in a time-lapse setup.

    Science.gov (United States)

    Hardarson, Thorir; Bungum, Mona; Conaghan, Joe; Meintjes, Marius; Chantilis, Samuel J; Molnar, Laszlo; Gunnarsson, Kristina; Wikland, Matts

    2015-12-01

    To study whether a culture medium that allows undisturbed culture supports human embryo development to the blastocyst stage equivalently to a well-established sequential media. Randomized, double-blinded sibling trial. Independent in vitro fertilization (IVF) clinics. One hundred twenty-eight patients, with 1,356 zygotes randomized into two study arms. Embryos randomly allocated into two study arms to compare embryo development on a time-lapse system using a single-step medium or sequential media. Percentage of good-quality blastocysts on day 5. Percentage of day 5 good-quality blastocysts was 21.1% (standard deviation [SD] ± 21.6%) and 22.2% (SD ± 22.1%) in the single-step time-lapse medium (G-TL) and the sequential media (G-1/G-2) groups, respectively. The mean difference (-1.2; 95% CI, -6.0; 3.6) between the two media systems for the primary end point was less than the noninferiority margin of -8%. There was a statistically significantly lower number of good-quality embryos on day 3 in the G-TL group [50.7% (SD ± 30.6%) vs. 60.8% (SD ± 30.7%)]. Four out of the 11 measured morphokinetic parameters were statistically significantly different for the two media used. The mean levels of ammonium concentration in the media at the end of the culture period was statistically significantly lower in the G-TL group as compared with the G-2 group. We have shown that a single-step culture medium supports blastocyst development equivalently to established sequential media. The ammonium concentrations were lower in the single-step media, and the measured morphokinetic parameters were modified somewhat. NCT01939626. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Seismic velocity site characterization of 10 Arizona strong-motion recording stations by spectral analysis of surface wave dispersion

    Science.gov (United States)

    Kayen, Robert E.; Carkin, Brad A.; Corbett, Skye C.

    2017-10-19

    Vertical one-dimensional shear wave velocity (VS) profiles are presented for strong-motion sites in Arizona for a suite of stations surrounding the Palo Verde Nuclear Generating Station. The purpose of the study is to determine the detailed site velocity profile, the average velocity in the upper 30 meters of the profile (VS30), the average velocity for the entire profile (VSZ), and the National Earthquake Hazards Reduction Program (NEHRP) site classification. The VS profiles are estimated using a non-invasive continuous-sine-wave method for gathering the dispersion characteristics of surface waves. Shear wave velocity profiles were inverted from the averaged dispersion curves using three independent methods for comparison, and the root-mean-square combined coefficient of variation (COV) of the dispersion and inversion calculations are estimated for each site.

  11. The determination of high-resolution spatio-temporal glacier motion fields from time-lapse sequences

    Science.gov (United States)

    Schwalbe, Ellen; Maas, Hans-Gerd

    2017-12-01

    This paper presents a comprehensive method for the determination of glacier surface motion vector fields at high spatial and temporal resolution. These vector fields can be derived from monocular terrestrial camera image sequences and are a valuable data source for glaciological analysis of the motion behaviour of glaciers. The measurement concepts for the acquisition of image sequences are presented, and an automated monoscopic image sequence processing chain is developed. Motion vector fields can be derived with high precision by applying automatic subpixel-accuracy image matching techniques on grey value patterns in the image sequences. Well-established matching techniques have been adapted to the special characteristics of the glacier data in order to achieve high reliability in automatic image sequence processing, including the handling of moving shadows as well as motion effects induced by small instabilities in the camera set-up. Suitable geo-referencing techniques were developed to transform image measurements into a reference coordinate system.The result of monoscopic image sequence analysis is a dense raster of glacier surface point trajectories for each image sequence. Each translation vector component in these trajectories can be determined with an accuracy of a few centimetres for points at a distance of several kilometres from the camera. Extensive practical validation experiments have shown that motion vector and trajectory fields derived from monocular image sequences can be used for the determination of high-resolution velocity fields of glaciers, including the analysis of tidal effects on glacier movement, the investigation of a glacier's motion behaviour during calving events, the determination of the position and migration of the grounding line and the detection of subglacial channels during glacier lake outburst floods.

  12. Novel migrating mouse neural crest cell assay system utilizing P0-Cre/EGFP fluorescent time-lapse imaging

    Directory of Open Access Journals (Sweden)

    Kawakami Minoru

    2011-11-01

    Full Text Available Abstract Background Neural crest cells (NCCs are embryonic, multipotent stem cells. Their long-range and precision-guided migration is one of their most striking characteristics. We previously reported that P0-Cre/CAG-CAT-lacZ double-transgenic mice showed significant lacZ expression in tissues derived from NCCs. Results In this study, by embedding a P0-Cre/CAG-CAT-EGFP embryo at E9.5 in collagen gel inside a culture glass slide, we were able to keep the embryo developing ex vivo for more than 24 hours; this development was with enough NCC fluorescent signal intensity to enable single-cell resolution analysis, with the accompanying NCC migration potential intact and with the appropriate NCC response to the extracellular signal maintained. By implantation of beads with absorbed platelet-derived growth factor-AA (PDGF-AA, we demonstrated that PDGF-AA acts as an NCC-attractant in embryos. We also performed assays with NCCs isolated from P0-Cre/CAG-CAT-EGFP embryos on culture plates. The neuromediator 5-hydroxytryptamine (5-HT has been known to regulate NCC migration. We newly demonstrated that dopamine, in addition to 5-HT, stimulated NCC migration in vitro. Two NCC populations, with different axial levels of origins, showed unique distribution patterns regarding migration velocity and different dose-response patterns to both 5-HT and dopamine. Conclusions Although avian species predominated over the other species in the NCC study, our novel system should enable us to use mice to assay many different aspects of NCCs in embryos or on culture plates, such as migration, division, differentiation, and apoptosis.

  13. Crustal structure beneath seismic stations deployed on rock in West Antarctica: New constrains on crustal shear wave velocities, Poisson's ratios and Moho depths

    Science.gov (United States)

    Ramirez, C.; Nyblade, A.; Wiens, D.; Aster, R. C.; Anandakrishnan, S.; Huerta, A. D.; Winberry, J. P.; Wilson, T. J.

    2016-12-01

    Over the past two decades there have been a number of broadband seismic networks deployed in Antarctica for investigating the deep earth structure and elucidating the nature of the crust and upper mantle beneath major tectonic features such as the Transantarctic Mountains, the Gamburtsev Subglacial Mountains, the West Antarctic Rift System, and the Marie Byrd Land Dome. Seismic data recorded by these networks have been analyzed to obtain estimates of crustal structure, such as Moho depth and Possion's ratio, leading to an improved understanding of Antarctic crustal structure. However, data from the different networks have been analyzed separately with a variety of modeling methods, resulting in non-uniform information on crustal properties. In this paper, we address the non-uniformity of available crustal parameters by modeling P wave receiver functions and Rayleigh wave velocities for all broadband stations in West Antarctica and the Transantarctic Mountains deployed on rock. Using the H-k stacking and a joint inversion methods and applying them to data from the 2000-2003 TAMSEIS and 2009-2015 POLENET networks, in addition to three permanent stations, we have obtained new estimates of Moho depth, crustal shear wave velocities and crustal Poisson's ratio. In addition, we report results for two new stations in West Antarctica. The ensemble of information on crustal thickness, crustal Poisson's ratio, and crustal shear wave velocity enables us to examine more comprehensively than previous studies the composition and structure of the crust beneath several tectonic blocks within the West Antarctica and the Transantarctic Mountains, and to comment further on their origin.

  14. Predicting injection related changes in seismic properties at Kevin Dome, north central Montana, using well logs and laboratory measurements

    Science.gov (United States)

    Saltiel, S.; Bonner, B. P.; Ajo Franklin, J. B.

    2014-12-01

    Time-lapse seismic monitoring (4D) is currently the primary technique available for tracking sequestered CO2 in a geologic storage reservoir away from monitoring wells. The main seismic responses to injection are those due to direct fluid substitution, changes in differential pressure, and chemical interactions with reservoir rocks; the importance of each depends on reservoir/injection properties and temporal/spatial scales of interest. As part of the Big Sky Carbon Sequestration Partnership, we are monitoring the upcoming large scale (1 million ton+) CO2 injection in Kevin Dome, north central Montana. As part of this research, we predict the relative significance of these three effects, as an aid in design of field surveys. Analysis is undertaken using existing open-hole well log data and cores from wells drilled at producer and injector pads as well as core experiments. For this demonstration site, CO2 will be produced from a natural reservoir and re-injected down dip, where the formation is saturated with brine. Effective medium models based on borehole seismic velocity measurements predict relatively small effects (less than 40 m/s change in V¬p) due to the injection of more compressible supercritical CO2. This is due to the stiff dolomite reservoir rock, with high seismic velocities (Vp~6000 m/s, Vs~3000 m/s) and fairly low porosity (<10%). Assuming pure dolomite mineralogy, these models predict a slight increase in Vp during CO2 injection. This velocity increase is due to the lower density of CO2 relative to brine; which outweighs the small change in modulus compared to the stiff reservoir rock. We present both room pressure and in-situ P/T ultrasonic experiments using core samples obtained from the reservoir; such measurements are undertaken to access the expected seismic velocities under pressurized injection. The reservoir appears to have fairly low permeability. Large-volume injection is expected to produce large local pore pressure increases, which may

  15. Crustal and upper mantle S-wave velocity structures across the Taiwan Strait from ambient seismic noise and teleseismic Rayleigh wave analyses

    Science.gov (United States)

    Huang, Y.; Yao, H.; Wu, F. T.; Liang, W.; Huang, B.; Lin, C.; Wen, K.

    2013-12-01

    Although orogeny seems to have stopped in western Taiwan large and small earthquakes do occur in the Taiwan Strait. Limited studies have focused on this region before and were barely within reach for comprehensive projects like TAICRUST and TAIGER for logistical reasons; thus, the overall crustal structures of the Taiwan Strait remain unknown. Time domain empirical Green's function (TDEGF) from ambient seismic noise to determine crustal velocity structure allows us to study an area using station pairs on its periphery. This research aims to resolve 1-D average crustal and upper mantle S-wave velocity (Vs) structures alone paths of several broadband station-pairs across the Taiwan Strait; 5-120 s Rayleigh wave phase velocity dispersion data derived by combining TDEGF and traditional surface wave two-station method (TS). The average Vs structures show significant differences in the upper 15 km as expected. In general, the highest Vs are observed in the coastal area of Mainland China and the lowest Vs appear along the southwest offshore of the Taiwan Island; they differ by about 0.6-1.1 km/s. For different parts of the Strait, the Vs are lower in the middle by about 0.1-0.2 km/s relative to those in the northern and southern parts. The overall crustal thickness is approximately 30 km, much thinner and less variable than under the Taiwan Island.

  16. Seismic velocities within the sedimentary succession of the Canada Basin and southern Alpha-Mendeleev Ridge, Arctic Ocean: evidence for accelerated porosity reduction?

    Science.gov (United States)

    Shimeld, John; Li, Qingmou; Chian, Deping; Lebedeva-Ivanova, Nina; Jackson, Ruth; Mosher, David; Hutchinson, Deborah R.

    2016-01-01

    The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity–depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity–depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity–depth profiles for each seismic trace. A thickness of 12–13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity–depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares

  17. The effects of pressure, temperature, and pore water on velocities in Westerly granite. [for seismic wave propagation

    Science.gov (United States)

    Spencer, J. W., Jr.; Nur, A. M.

    1976-01-01

    A description is presented of an experimental assembly which has been developed to conduct concurrent measurements of compressional and shear wave velocities in rocks at high temperatures and confining pressures and with independent control of the pore pressure. The apparatus was used in studies of the joint effects of temperature, external confining pressure, and internal pore water on sonic velocities in Westerly granite. It was found that at a given temperature, confining pressure has a larger accelerating effect on compressional waves in dry rock, whereas at a given confining pressure, temperature has a larger retarding effect on shear waves.

  18. BayesMT: Bayesian inference for the seismic moment tensor using regional and teleseismic-P waveforms with first-motion data and a calibrated prior distribution of velocity models

    Science.gov (United States)

    Ford, S. R.; Chiang, A.; Kim, S.; Letort, J.; Tkalcic, H.; Walter, W. R.

    2016-12-01

    The largest source of uncertainty in any source inversion is the velocity model used to construct the transfer function employed in the forward model that relates observed ground motion to the seismic moment tensor. We attempt to incorporate this uncertainty into an estimation of the seismic moment tensor using a posterior distribution of velocity models based on different and complementary data sets, including thickness constraints, velocity profiles, gravity data, surface wave group velocities, and regional body wave traveltimes. The posterior distribution of velocity models is then used to construct a prior distribution of Green's functions for use in Bayesian inference of an unknown seismic moment tensor using regional and teleseismic-P waveforms with first-motion data. The use of multiple data sets is important for gaining resolution to different components of the moment tensor. The combined likelihood is estimated using data-specific error models and the posterior of the seismic moment tensor is estimated and interpreted in terms of most-probable source-type. Prepared by LLNL under Contract DE-AC52-07NA27344. LLNL-ABS-676976.

  19. Comparative in situ X-ray Diffraction Study of San Carlos Olivine: Influence of Water on the 410 km Seismic Velocity Jump in Earth’s Mantle

    Energy Technology Data Exchange (ETDEWEB)

    J Chen; H Liu; J Girard

    2011-12-31

    A comparative study of the equation of states of hydrous (0.4 wt% H{sub 2}O) and anhydrous San Carlos olivine (<30 ppm H2O) was conducted using synchrotron X-rays up to 11 GPa in a diamond anvil cell (DAC) at ambient temperature. Both samples were loaded in the same high-pressure chamber of the DAC to eliminate the possible pressure difference in different experiments. The obtained compression data were fitted to the third-order Birch-Murnaghan equation of state, yielding a bulk modulus K{sub 0} = 123(3) GPa for hydrous olivine and K{sub 0} = 130(4) GPa for anhydrous olivine as K{sub 0}' is fixed at 4.6. Therefore, 0.4 wt% H{sub 2}2O in olivine results in a 5% reduction in bulk modulus. Previous studies reported bulk modulus reduction by water in olivine's high-pressure polymorph (wadsleyite), to which the transformation from olivine gives rise to the seismic discontinuity at 410 km depth. The new data results in a reduction in the magnitude of the discontinuity by 50% in v{sub P} and 30% in v{sub S} (for 1:5 water partitioning between olivine and wadsleyite) with respect to anhydrous mantle. Previous knowledge of the influence of water on this phase transition has been in opposition to a large amount of water [e.g., 200 ppm by Wood (1995)] existing at 410 km depth. Calculation of the seismic velocities based on newly available elasticity data of the hydrous phases indicates that the presence of water is favorable for the mineral composition model (pyrolite) and seismic observations in terms of the magnitude of the 410 km discontinuity.

  20. Combining time-lapse electrical resistivity, suction cup and tensiometer measurements to monitor snowmelt and solute transport at Oslo airport, Gardermoen

    Science.gov (United States)

    Bloem, Esther; French, Helen K.

    2013-04-01

    Geophysical methods provide indirect measurements of subsurface properties over larger volumes than traditional techniques, and are potentially cost-efficient. However, the usefulness of any individual set of geophysical measurements (akin to a snapshot at one point in time) is severely limited by the problem of non-uniqueness or ambiguity when used to study contaminated sites, where the attendant processes vary in space and time. To make progress on soil contamination assessment and site characterization there is a strong need to integrate quasi field-scale, extensively instrumented tools, with non-invasive (geophysical) methods. The impact of annual infiltration of large quantities of de-icing chemicals at Oslo airport, Gardermoen, represents common challenge for all airports with winter frost. It is also similar to the challenge posed by de-icing salt application along roads. To improve risk assessment, monitoring, and treatment strategies for natural attenuation, we require a better understanding on the resistivity effects from infiltrating snowmelt and contaminant movement to the methods suitable for monitoring resistivity changes over time at contaminated sites. Electrical and electromagnetic methods are widely applied for soil mapping and detecting of contaminated plumes. Time-lapse measurements have become a common method to characterize changes in water saturation and solute transport in the unsaturated zone (French and Binley, 2004; French et al. 2002). The non-uniqueness of the interpretation techniques can be reduced by constraining the inversion through the addition of independent measurements along the same profile. Such measurements include soil physical properties, soil suction, contaminant concentration and temperatures. At the research field station at Gardermoen, a degradable de-icing chemical and an inactive tracer were added to the snow cover prior to snowmelt. In order to link geophysical measurements to solute transport processes in the

  1. Seismic imaging of deep low-velocity zone beneath the Dead Sea basin and transform fault: Implications for strain localization and crustal rigidity

    Science.gov (United States)

    ten Brink, Uri S.; Al-Zoubi, A. S.; Flores, C.H.; Rotstein, Y.; Qabbani, I.; Harder, S.H.; Keller, Gordon R.

    2006-01-01

    New seismic observations from the Dead Sea basin (DSB), a large pull-apart basin along the Dead Sea transform (DST) plate boundary, show a low velocity zone extending to a depth of 18 km under the basin. The lower crust and Moho are not perturbed. These observations are incompatible with the current view of mid-crustal strength at low temperatures and with support of the basin's negative load by a rigid elastic plate. Strain softening in the middle crust is invoked to explain the isostatic compensation and the rapid subsidence of the basin during the Pleistocene. Whether the deformation is influenced by the presence of fluids and by a long history of seismic activity on the DST, and what the exact softening mechanism is, remain open questions. The uplift surrounding the DST also appears to be an upper crustal phenomenon but its relationship to a mid-crustal strength minimum is less clear. The shear deformation associated with the transform plate boundary motion appears, on the other hand, to cut throughout the entire crust. Copyright 2006 by the American Geophysical Union.

  2. Application of RVA and Time-Lapse Photography to Explore Effects of Extent of Chlorination, Milling Extraction Rate, and Particle-Size Reduction of Flour on Cake-Baking Functionality

    Science.gov (United States)

    Three factors (extent of chlorination, milling extraction rate and particle-size reduction) in the cake-bakeing functionality of Croplan 594W flour were explored by Rapid Visco-Analyzer (RVA) and time-lapse photography. The extent of chlorination and milling extraction rate showed dramatic effects,...

  3. Quantitative high-resolution observations of soil water dynamics in a complicated architecture using time-lapse ground-penetrating radar

    Science.gov (United States)

    Klenk, P.; Jaumann, S.; Roth, K.

    2015-03-01

    High-resolution time-lapse ground-penetrating radar (GPR) observations of advancing and retreating water tables can yield a wealth of information about near-surface water content dynamics. In this study, we present and analyze a series of imbibition, drainage and infiltration experiments that have been carried out at our artificial ASSESS test site and observed with surface-based GPR. The test site features a complicated but known subsurface architecture constructed with three different kinds of sand. It allows the study of soil water dynamics with GPR under a wide range of different conditions. Here, we assess in particular (i) the feasibility of monitoring the dynamic shape of the capillary fringe reflection and (ii) the relative precision of monitoring soil water dynamics averaged over the whole vertical extent by evaluating the bottom reflection. The phenomenology of the GPR response of a dynamically changing capillary fringe is developed from a soil physical point of view. We then explain experimentally observed phenomena based on numerical simulations of both the water content dynamics and the expected GPR response.

  4. Quantitative high-resolution observations of soil water dynamics in a complicated architecture with time-lapse Ground-Penetrating Radar

    Science.gov (United States)

    Klenk, P.; Jaumann, S.; Roth, K.

    2014-11-01

    High-resolution time-lapse Ground-Penetrating Radar (GPR) observations of advancing and retreating water tables can yield a wealth of information about near-surface water content dynamics. In this study, we present and analyze a series of imbibition, drainage and infiltration experiments which have been carried out at our artificial ASSESS test site and observed with surface based GPR. The test site features a complicated but known subsurface architecture constructed with three different kinds of sand. It allows studying soil water dynamics with GPR under a wide range of different conditions. Here, we assess in particular (i) the accurate determination of soil water dynamics averaged over the whole vertical extent by evaluating the bottom reflection and (ii) the feasibility of monitoring the dynamic shape of the capillary fringe reflection. The phenomenology of the GPR response of a dynamically changing capillary fringe is developed from a soil physical point of view. We then explain experimentally observed phenomena based on numerical simulations of both the water content dynamics and the expected GPR response.

  5. New algorithm to determine true colocalization in combination with image restoration and time-lapse confocal microscopy to MAP kinases in mitochondria.

    Directory of Open Access Journals (Sweden)

    Jorge Ignacio Villalta

    Full Text Available The subcellular localization and physiological functions of biomolecules are closely related and thus it is crucial to precisely determine the distribution of different molecules inside the intracellular structures. This is frequently accomplished by fluorescence microscopy with well-characterized markers and posterior evaluation of the signal colocalization. Rigorous study of colocalization requires statistical analysis of the data, albeit yet no single technique has been established as a standard method. Indeed, the few methods currently available are only accurate in images with particular characteristics. Here, we introduce a new algorithm to automatically obtain the true colocalization between images that is suitable for a wide variety of biological situations. To proceed, the algorithm contemplates the individual contribution of each pixel's fluorescence intensity in a pair of images to the overall Pearsońs correlation and Manders' overlap coefficients. The accuracy and reliability of the algorithm was validated on both simulated and real images that reflected the characteristics of a range of biological samples. We used this algorithm in combination with image restoration by deconvolution and time-lapse confocal microscopy to address the localization of MEK1 in the mitochondria of different cell lines. Appraising the previously described behavior of Akt1 corroborated the reliability of the combined use of these techniques. Together, the present work provides a novel statistical approach to accurately and reliably determine the colocalization in a variety of biological images.

  6. Proliferation kinetics of cultured cells after irradiation with X-rays and 14 MeV neutrons studied by time-lapse cinematography.

    Science.gov (United States)

    Kooi, M W; Stap, J; Barendsen, G W

    1984-06-01

    Exponentially growing cells of an established line derived from a mouse osteosarcoma (MOS) have been studied by time-lapse cinematography after irradiation with 3 Gy of 200 kV X-rays or 1.5 Gy of 14 MeV neutrons. Cell cycle times (Tc) of individual cells and their progeny in three subsequent generations as well as the occurrence of aberrant mitosis have been determined to evaluate the variation in expression of damage in relation to the stage in the intermitotic cycle and the radiation quality. The results show that the radiation doses applied cause an equal elongation of the mean Tc, which is largest in the irradiated cells but persists in the three subsequent generations. After 3 Gy of X-rays, mitotic delay is largest in cells irradiated in later stages of the cycle, but this difference is not observed after 1.5 Gy of 14 MeV neutrons. In subsequent generations the Tc values show larger variations among descendents of cells treated in the same stage of the cycle as compared to controls but this variation is equal for the doses of X-rays and neutrons applied. Division probability was significantly reduced in irradiated cells as well as in subsequent generations, whereby with neutrons as compared to X-rays the damage is expressed in earlier generations, with less variation as a function of the cell cycle.

  7. Visualization of living terminal hypertrophic chondrocytes of growth plate cartilage in situ by differential interference contrast microscopy and time-lapse cinematography.

    Science.gov (United States)

    Farnum, C E; Turgai, J; Wilsman, N J

    1990-09-01

    The functional unit within the growth plate consists of a column of chondrocytes that passes through a sequence of phases including proliferation, hypertrophy, and death. It is important to our understanding of the biology of the growth plate to determine if distal hypertrophic cells are viable, highly differentiated cells with the potential of actively controlling terminal events of endochondral ossification prior to their death at the chondro-osseous junction. This study for the first time reports on the visualization of living hypertrophic chondrocytes in situ, including the terminal hypertrophic chondrocyte. Chondrocytes in growth plate explants are visualized using rectified differential interference contrast microscopy. We record and measure, using time-lapse cinematography, the rate of movement of subcellular organelles at the limit of resolution of this light microscopy system. Control experiments to assess viability of hypertrophic chondrocytes include coincubating organ cultures with the intravital dye fluorescein diacetate to assess the integrity of the plasma membrane and cytoplasmic esterases. In this system, all hypertrophic chondrocytes, including the very terminal chondrocyte, exist as rounded, fully hydrated cells. By the criteria of intravital dye staining and organelle movement, distal hypertrophic chondrocytes are identical to chondrocytes in the proliferative and early hypertrophic cell zones.

  8. Proliferation kinetics of cultured cells after irradiation with X-rays and 14 MeV neutrons studied by time-lapse cinematography

    International Nuclear Information System (INIS)

    Kooi, M.W.; Stap, J.; Barendsen, G.W.

    1984-01-01

    Exponentially growing cells of an established line derived from a mouse osteosarcoma (MOS) have been studied by time-lapse cinematography after irradiation with 3 Gy of 200 kV X- rays or 1.5 Gy of 14 MeV neutrons. The results show that the radiation doses applied cause an equal elongation of the mean cell cycle time Tsub(c), which is largest in the irradiated cells but persists in the three subsequent generations. After 3 Gy of X-rays, mitotic delay is largest in cells irradiated in later stages of the cycle, but this difference is not observed after 1.5 Gy of 14 MeV neutrons. In subsequent generations the Tsub(c) values show larger variations among descendents of cells treated in the same stage of the cycle as compared to controls but this variation is equal for the doses of X-rays and neutrons applied. Division probability was significantly reduced in irradiated cells as well as in subsequent generations, whereas with neutrons as compared to X-rays the damage is expressed in earlier generations, with less variation as a function of the cell cycle. (author)

  9. CellDyM: A room temperature operating cryogenic cell for the dynamic monitoring of snow metamorphism by time-lapse X-ray microtomography

    Science.gov (United States)

    Calonne, N.; Flin, F.; Lesaffre, B.; Dufour, A.; Roulle, J.; Puglièse, P.; Philip, A.; Lahoucine, F.; Geindreau, C.; Panel, J.-M.; Roscoat, S. Rolland; Charrier, P.

    2015-05-01

    Monitoring the time evolution of snow microstructure in 3-D is crucial for a better understanding of snow metamorphism. We, therefore, designed a cryogenic cell that precisely controls the experimental conditions of a sample while it is scanned by X-ray tomography. Based on a thermoelectrical regulation and a vacuum insulation, the cell operates at room temperature. It is, thus, adaptable to diverse scanners, offering advantages in terms of imaging techniques, resolution, and speed. Three-dimensional time-lapse series were obtained under equitemperature and temperature gradient conditions at a 7.8 μm precision. The typical features of each metamorphism and the anisotropic faceting behavior between the basal and prismatic planes, known to occur close to -2°C, were observed in less than 30 h. These results are consistent with the temperature fields expected from heat conduction simulations through the cell. They confirm the cell's accuracy and the interest of relatively short periods to study snow metamorphism.

  10. Significantly improved precision of cell migration analysis in time-lapse video microscopy through use of a fully automated tracking system

    Directory of Open Access Journals (Sweden)

    Seufferlein Thomas

    2010-04-01

    Full Text Available Abstract Background Cell motility is a critical parameter in many physiological as well as pathophysiological processes. In time-lapse video microscopy, manual cell tracking remains the most common method of analyzing migratory behavior of cell populations. In addition to being labor-intensive, this method is susceptible to user-dependent errors regarding the selection of "representative" subsets of cells and manual determination of precise cell positions. Results We have quantitatively analyzed these error sources, demonstrating that manual cell tracking of pancreatic cancer cells lead to mis-calculation of migration rates of up to 410%. In order to provide for objective measurements of cell migration rates, we have employed multi-target tracking technologies commonly used in radar applications to develop fully automated cell identification and tracking system suitable for high throughput screening of video sequences of unstained living cells. Conclusion We demonstrate that our automatic multi target tracking system identifies cell objects, follows individual cells and computes migration rates with high precision, clearly outperforming manual procedures.

  11. Revelation of Different Nanoparticle-Uptake Behavior in Two Standard Cell Lines NIH/3T3 and A549 by Flow Cytometry and Time-Lapse Imaging

    Directory of Open Access Journals (Sweden)

    André Jochums

    2017-07-01

    Full Text Available The uptake of nanomaterials into different cell types is a central pharmacological issue for the determination of nanotoxicity as well as for the development of drug delivery strategies. Most responses of the cells depend on their intracellular interactions with nanoparticles (NPs. Uptake behavior can be precisely investigated in vitro, with sensitive high throughput methods such as flow cytometry. In this study, we investigated two different standard cell lines, human lung carcinoma (A549 and mouse fibroblast (NIH/3T3 cells, regarding their uptake behavior of titanium dioxide NPs. Cells were incubated with different concentrations of TiO2 NPs and samples were taken at certain time points to compare the uptake kinetics of both cell lines. Samples were analyzed with the help of flow cytometry by studying changes in the side and forward scattering signal. To additionally enable a detection via fluorescence, NPs were labeled with the fluorescent dye fluorescein isothiocyanate (FITC and propidium iodide (PI. We found that NIH/3T3 cells take up the studied NPs more efficiently than A549 cells. These findings were supported by time-lapse microscopic imaging of the cells incubated with TiO2 NPs. Our results confirm that the uptake behavior of individual cell types has to be considered before interpreting any results of nanomaterial studies.

  12. Monitoring a temporal change of seismic velocity in a geothermal reservoir; Chinetsu choryuso hendo ni tomonau jishinha sokudo henka kenshutsu no kokoromi

    Energy Technology Data Exchange (ETDEWEB)

    Sugihara, M.; Nishi, Y.; Tosha, T. [Geological Survey of Japan, Tsukuba (Japan)

    1997-10-22

    Data derived at the Kakkonda geothermal area were used to discuss functions of monitoring a temporal change of seismic velocity in geothermal reservoir. The data were selected from about 50 microtremors generated in the vicinity of the area during one year in 1986. Two out of the selected microtremors were earthquakes with a magnitude of 2.7 both accompanying small precursor events. The magnitude of 2.7 may be small under normal definition, but the earthquakes are thought relatively strong because the degree of fracture adjacent to the reservoir is concentrated in a small space. This condition could be a cause of expansion of the fracture zone. The analysis was carried out according what is described by Ratdomopurbo and Poupinet. More specifically, certain time sections were taken on each certain time to fit it with the initial movement time of P-waves on two similar earthquakes, cross spectra were calculated, and phase difference in the two earthquakes was evaluated from the phase spectra. As a result, no distinct change was detected in the velocity. 5 figs.

  13. Stochastic velocity inversion of seismic reflection/refraction traveltime data for rift structure of the southwest Barents Sea

    DEFF Research Database (Denmark)

    Clark, Stephen A.; Faleide, Jan Inge; Hauser, Juerg

    2013-01-01

    reflection profiles. We utilize layer-based raytracing in a Markov Chain Monte Carlo (MCMC) inversion to determine a probabilistic velocity model constraining the sedimentary rocks, crystalline crust, and uppermost mantle in a complex tectonic regime. The profile images a wide range of crustal types and ages...... with the amount of overlap derived from published plate reconstructions. Local β factors approach 3, where Bjørnøya Basin reaches a depth of more than 13 km. Volcanics, carbonates, salt, diagenesis and metamorphism make deep sedimentary basin fill difficult to distinguish from original, pre-rift crystalline crust...

  14. The use of computerized video time lapse to study cell death in rat embryo cells transfected with c-ha-ras or c-myc

    International Nuclear Information System (INIS)

    Forrester, H.B.; Vidair, C.A.; Dewey, W.C.; Ling, C.C.

    1998-01-01

    Full text: Individual rat embryo fibroblasts that had been transfected with the c-myc (REC:myc) or c-Ha ras (REC:ras) oncogene were followed after irradiation using a computer video time lapse (CVTL) system in order to quantify the lethal events that resulted in loss of clonogenic survival after irradiation. By followed the cells for 2 to 3 generations before irradiation we were able to determine where they were in the cell cycle at the time of irradiation for cell cycle analysis. After irradiation, the individual cells and their progeny were followed in multiple fields for 5-6 days Then, pedigrees for individual irradiated cells were determined by noting the times of divisions fusions, and cell death. After X-irradiation, the clonogenic survival values for these two cell lines are similar. However, by using computerized video time lapse (CVTL) to follow individual cells we found that the loss of clonogenic survival was due to two different processes, cell death and a senescent-like process. The loss of clonogenic survival of x-irradiated (9.5 and 4 Gy) REC:myc cells was attributed almost entirely to the cells dying by apoptosis (∼99 and 90%). In contrast, approximately 60% of the x-irradiated (9.5 Gy) non-clonogenic REC:ras cells died by apoptosis (with a very small amount of necrosis), and the other 40% underwent a senescent-type process in which some of the cells and their progeny stopped dividing but remained as viable cells throughout 140 hours of observation. Both processes usually occurred after the cells had divided and continued to occur in the cells' progeny for up to five divisions after irradiation. The mode of cell death in the progeny of a non-clonogenic cell can be determined only by using CVTL and can not be determined by conventional clonogenic survival experiments. Also, only by following the individual cells and their progeny can the true amount of apoptosis be determined. The cumulative percentage of apoptosis scored in whole populations

  15. Understanding leachate flow in municipal solid waste landfills by combining time-lapse ERT and subsurface flow modelling - Part II: Constraint methodology of hydrodynamic models.

    Science.gov (United States)

    Audebert, M; Oxarango, L; Duquennoi, C; Touze-Foltz, N; Forquet, N; Clément, R

    2016-09-01

    Leachate recirculation is a key process in the operation of municipal solid waste landfills as bioreactors. To ensure optimal water content distribution, bioreactor operators need tools to design leachate injection systems. Prediction of leachate flow by subsurface flow modelling could provide useful information for the design of such systems. However, hydrodynamic models require additional data to constrain them and to assess hydrodynamic parameters. Electrical resistivity tomography (ERT) is a suitable method to study leachate infiltration at the landfill scale. It can provide spatially distributed information which is useful for constraining hydrodynamic models. However, this geophysical method does not allow ERT users to directly measure water content in waste. The MICS (multiple inversions and clustering strategy) methodology was proposed to delineate the infiltration area precisely during time-lapse ERT survey in order to avoid the use of empirical petrophysical relationships, which are not adapted to a heterogeneous medium such as waste. The infiltration shapes and hydrodynamic information extracted with MICS were used to constrain hydrodynamic models in assessing parameters. The constraint methodology developed in this paper was tested on two hydrodynamic models: an equilibrium model where, flow within the waste medium is estimated using a single continuum approach and a non-equilibrium model where flow is estimated using a dual continuum approach. The latter represents leachate flows into fractures. Finally, this methodology provides insight to identify the advantages and limitations of hydrodynamic models. Furthermore, we suggest an explanation for the large volume detected by MICS when a small volume of leachate is injected. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Monitoring the evolution and migration of a methane gas plume in an unconfined sandy aquifer using time-lapse GPR and ERT

    Science.gov (United States)

    Steelman, Colby M.; Klazinga, Dylan R.; Cahill, Aaron G.; Endres, Anthony L.; Parker, Beth L.

    2017-10-01

    Fugitive methane (CH4) leakage associated with conventional and unconventional petroleum development (e.g., shale gas) may pose significant risks to shallow groundwater. While the potential threat of stray (CH4) gas in aquifers has been acknowledged, few studies have examined the nature of its migration and fate in a shallow groundwater flow system. This study examines the geophysical responses observed from surface during a 72 day field-scale simulated CH4 leak in an unconfined sandy aquifer at Canadian Forces Base Borden, Canada, to better understand the transient behaviour of fugitive CH4 gas in the subsurface. Time-lapse ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) were used to monitor the distribution and migration of the gas-phase and assess any impacts to groundwater hydrochemistry. Geophysical measurements captured the transient formation of a CH4 gas plume emanating from the injector, which was accompanied by an increase in total dissolved gas pressure (PTDG). Subsequent reductions in PTDG were accompanied by reduced bulk resistivity around the injector along with an increase in the GPR reflectivity along horizontal bedding reflectors farther downgradient. Repeat temporal GPR reflection profiling identified three events with major peaks in reflectivity, interpreted to represent episodic lateral CH4 gas release events into the aquifer. Here, a gradual increase in PTDG near the injector caused a sudden lateral breakthrough of gas in the direction of groundwater flow, causing free-phase CH4 to migrate much farther than anticipated based on groundwater advection. CH4 accumulated along subtle permeability boundaries demarcated by grain-scale bedding within the aquifer characteristic of numerous Borden-aquifer multi-phase flow experiments. Diminishing reflectivity over a period of days to weeks suggests buoyancy-driven migration to the vadose zone and/or CH4 dissolution into groundwater. Lateral and vertical CH4 migration was

  17. Time-lapse cinematography-compatible polystyrene-based microwell culture system: a novel tool for tracking the development of individual bovine embryos.

    Science.gov (United States)

    Sugimura, Satoshi; Akai, Tomonori; Somfai, Tamás; Hirayama, Muneyuki; Aikawa, Yoshio; Ohtake, Masaki; Hattori, Hideshi; Kobayashi, Shuji; Hashiyada, Yutaka; Konishi, Kazuyuki; Imai, Kei

    2010-12-01

    We have developed a polystyrene-based well-of-the-well (WOW) system using injection molding to track individual embryos throughout culture using time-lapse cinematography (TLC). WOW culture of bovine embryos following in vitro fertilization was compared with conventional droplet culture (control). No differences between control- and WOW-cultured embryos were observed during development to the blastocyst stage. Morphological quality and inner cell mass (ICM) and trophectoderm (TE) cell numbers were not different between control- and WOW-derived blastocysts; however, apoptosis in both the ICM and TE cells was reduced in WOW culture (P < 0.01). Oxygen consumption in WOW-derived blastocysts was closer to physiological level than that of control-derived blastocysts. Moreover, WOW culture improved embryo viability, as indicated by increased pregnancy rates at Days 30 and 60 after embryo transfer (P < 0.05). TLC monitoring was performed to evaluate the cleavage pattern and the duration of the first cell cycle of embryos from oocytes collected by ovum pickup; correlations with success of pregnancy were determined. Logistic regression analysis indicated that the cleavage pattern correlated with success of pregnancy (P < 0.05), but cell cycle length did not. Higher pregnancy rates (66.7%) were observed for animals in which transferred blastocysts had undergone normal cleavage, identified by the presence of two blastomeres of the same size without fragmentation, than among those with abnormal cleavage (33.3%). These results suggest that our microwell culture system is a powerful tool for producing and selecting healthy embryos and for identifying viability biomarkers.

  18. Remotely Measuring Trash Fluxes in the Flood Canals of Megacities with Time Lapse Cameras and Computer Vision Algorithms - a Case Study from Jakarta, Indonesia.

    Science.gov (United States)

    Sedlar, F.; Turpin, E.; Kerkez, B.

    2014-12-01

    As megacities around the world continue to develop at breakneck speeds, future development, investment, and social wellbeing are threatened by a number of environmental and social factors. Chief among these is frequent, persistent, and unpredictable urban flooding. Jakarta, Indonesia with a population of 28 million, is a prime example of a city plagued by such flooding. Yet although Jakarta has ample hydraulic infrastructure already in place with more being constructed, the increasingly severity of the flooding it experiences is not from a lack of hydraulic infrastructure but rather a failure of existing infrastructure. As was demonstrated during the most recent floods in Jakarta, the infrastructure failure is often the result of excessive amounts of trash in the flood canals. This trash clogs pumps and reduces the overall system capacity. Despite this critical weakness of flood control in Jakarta, no data exists on the overall amount of trash in the flood canals, much less on how it varies temporally and spatially. The recent availability of low cost photography provides a means to obtain such data. Time lapse photography postprocessed with computer vision algorithms yields a low cost, remote, and automatic solution to measuring the trash fluxes. When combined with the measurement of key hydrological parameters, a thorough understanding of the relationship between trash fluxes and the hydrology of massive urban areas becomes possible. This work examines algorithm development, quantifying trash parameters, and hydrological measurements followed by data assimilation into existing hydraulic and hydrological models of Jakarta. The insights afforded from such an approach allows for more efficient operating of hydraulic infrastructure, knowledge of when and where critical levels of trash originate from, and the opportunity for community outreach - which is ultimately needed to reduce the trash in the flood canals of Jakarta and megacities around the world.

  19. Ionomycin-induced calcium influx induces neurite degeneration in mouse neuroblastoma cells: analysis of a time-lapse live cell imaging system.

    Science.gov (United States)

    Nakamura, Saki; Nakanishi, Ayumi; Takazawa, Minami; Okihiro, Shunsuke; Urano, Shiro; Fukui, Koji

    2016-01-01

    Reactive oxygen species induce neuronal cell death. However, the detailed mechanisms of cell death have not yet been elucidated. Previously, we reported neurite degeneration before the induction of cell death. Here, we attempted to elucidate the mechanisms of neurite degeneration before the induction of cell death using the neuroblastoma N1E-115 cell line and a time-lapse live cell imaging system. Treatment with the calcium ionophore ionomycin induced cell death and neurite degeneration in a concentration- and time-dependent manner. Treatment with a low concentration of ionomycin immediately produced a significant calcium influx into the intracellular region in N1E-115 cells. After 1-h incubation with ionomycin, the fluorescence emission of MitoSOX TM increased significantly compared to the control. Finally, analysis using a new mitochondrial specific fluorescence dye, MitoPeDPP, indicated that treatment with ionomycin significantly increased the mitochondrial lipid hydroperoxide production in N1E-115 cells. The fluorescence emissions of Fluo-4 AM and MitoPeDPP were detected in the cell soma and neurite regions in ionomycin-treated N1E-115 cells. However, the emissions of neurites were much lower than those of the cell soma. TBARS values of ionomycin-treated cells significantly increased compared to the control. These results indicate that ionomycin induces calcium influx into the intracellular region and reactive oxygen species production in N1E-115 cells. Lipid hydroperoxide production was induced in ionomycin-treated N1E-115 cells. Calcium influx into the intracellular region is a possible activator of neurite degeneration.

  20. The turbulent life of juvenile icebergs: Observations from an array of high-rate time-lapse cameras in LeConte Bay, Alaska

    Science.gov (United States)

    Kienholz, C.; Amundson, J. M.; Jackson, R. H.; Motyka, R. J.; Nash, J. D.; Sutherland, D.

    2017-12-01

    Tidewater glacier behavior is driven by poorly understood processes occurring at the ice-ocean interface, including sedimentation and erosion, iceberg calving, and submarine melting. These processes are inherently difficult to observe, calling for innovative field techniques and numerical models. As part of a multi-year field effort to constrain ocean-glacier heat and mass exchange, we deployed an array of high-rate time-lapse cameras (sampling intervals between 15 seconds and 2 minutes) to monitor the terminus of LeConte Glacier and its proglacial fjord. The camera array has operated continuously for more than a year. Our high sampling rates enable tracking of iceberg motion with optical flow algorithms, which have been used widely in computer vision but less so in glaciology and oceanography. Such algorithms track individual features (e.g., corners of icebergs), which is ideal for iceberg-rich fjords, where motion can vary substantially over short temporal and spatial scales (e.g., due to complex surface currents or different iceberg sizes). We process our data to quantify subdaily to seasonal patterns in surface currents and relate them to forcing from tides, wind, and glacier runoff. Flow is most variable close to the glacier terminus due to frequent calving events and turbulent plume dynamics. Farther down fjord, more consistent patterns emerge, driven by tides, wind, and runoff and altered by fjord geometry. Our tracking results compare favorably to and complement our Acoustic Doppler Current Profiler measurements from boats and moorings. Given their high spatial and temporal resolution, our observations will place important surface constraints on forthcoming hydrodynamic modeling efforts. The deployment of the cameras in a harsh environment and the corresponding image processing provided an opportunity to test hardware and software thoroughly, which will prove useful for similar systems at other glaciers.

  1. Vapor flux and recrystallization during dry snow metamorphism under a steady temperature gradient as observed by time-lapse micro-tomography

    Directory of Open Access Journals (Sweden)

    B. R. Pinzer

    2012-10-01

    Full Text Available Dry snow metamorphism under an external temperature gradient is the most common type of recrystallization of snow on the ground. The changes in snow microstructure modify the physical properties of snow, and therefore an understanding of this process is essential for many disciplines, from modeling the effects of snow on climate to assessing avalanche risk. We directly imaged the microstructural changes in snow during temperature gradient metamorphism (TGM under a constant gradient of 50 K m−1, using in situ time-lapse X-ray micro-tomography. This novel and non-destructive technique directly reveals the amount of ice that sublimates and is deposited during metamorphism, in addition to the exact locations of these phase changes. We calculated the average time that an ice volume stayed in place before it sublimated and found a characteristic residence time of 2–3 days. This means that most of the ice changes its phase from solid to vapor and back many times in a seasonal snowpack where similar temperature conditions can be found. Consistent with such a short timescale, we observed a mass turnover of up to 60% of the total ice mass per day. The concept of hand-to-hand transport for the water vapor flux describes the observed changes very well. However, we did not find evidence for a macroscopic vapor diffusion enhancement. The picture of {temperature gradient metamorphism} produced by directly observing the changing microstructure sheds light on the micro-physical processes and could help to improve models that predict the physical properties of snow.

  2. Ambient Seismic Imaging of Hydraulically Active Fractures at km Depths

    Science.gov (United States)

    Malin, P. E.; Sicking, C.

    2017-12-01

    Streaming Depth Images of ambient seismic signals using numerous, densely-distributed, receivers have revealed their connection to hydraulically active fractures at 0.5 to 5 km depths. Key for this type of imaging is very high-fold stacking over both multiple receives and periods of a few hours. Also important is suppression of waveforms from fixed, repeating sources such as pumps, generators, and traffic. A typical surface-based ambient SDI survey would use a 3D seismic receiver grid. It would have 1,000 to 4,000 uniformly distributed receivers at a density of 50/km2over the target. If acquired by borehole receivers buried 100 m deep, the density can be dropped by an order of magnitude. We show examples of the acquisition and signal processing scenarios used to produce the ambient images. (Sicking et al., SEG Interpretation, Nov 2017.) While the fracture-fluid source connection of SDI has been verified by drilling and various types of hydraulic tests, the precise nature of the signal's origin is not clear. At the current level of observation, the signals do not have identifiable phases, but can be focused using P wave velocities. Suggested sources are resonances of pressures fluctuations in the fractures, or small, continuous, slips on fractures surfaces. In either case, it appears that the driving mechanism is tectonic strain in an inherently unstable crust. Solid earth tides may enhance these strains. We illustrate the value of the ambient SDI method in its industrial application by showing case histories from energy industry and carbon-capture-sequestration projects. These include ambient images taken before, during, and after hydraulic treatments in un-conventional reservoirs. The results show not only locations of active fractures, but also their time responses to stimulation and production. Time-lapse ambient imaging can forecast and track events such as well interferences and production changes that can result from nearby treatments.

  3. Live-cell time-lapse imaging and single-cell tracking of in vitro cultured neural stem cells - Tools for analyzing dynamics of cell cycle, migration, and lineage selection.

    Science.gov (United States)

    Piltti, Katja M; Cummings, Brian J; Carta, Krystal; Manughian-Peter, Ayla; Worne, Colleen L; Singh, Kulbir; Ong, Danier; Maksymyuk, Yuriy; Khine, Michelle; Anderson, Aileen J

    2018-01-15

    Neural stem cell (NSC) cultures have been considered technically challenging for time-lapse analysis due to high motility, photosensitivity, and growth at confluent densities. We have tested feasibility of long-term live-cell time-lapse analysis for NSC migration and differentiation studies. Here, we describe a method to study the dynamics of cell cycle, migration, and lineage selection in cultured multipotent mouse or human NSCs using single-cell tracking during a long-term, 7-14 day live-cell time-lapse analysis. We used in-house made PDMS inserts with five microwells on a glass coverslip petri-dish to constrain NSC into the area of acquisition during long-term live-cell imaging. In parallel, we have defined image acquisition settings for single-cell tracking of cell cycle dynamics using Fucci-reporter mouse NSC for 7 days as well as lineage selection and migration using human NSC for 14 days. Overall, we show that adjustments of live-cell analysis settings can extend the time period of single-cell tracking in mouse or human NSC from 24-72 h up to 7-14 days and potentially longer. However, we emphasize that experimental use of repeated fluorescence imaging will require careful consideration of controls during acquisition and analysis. Copyright © 2017. Published by Elsevier Inc.

  4. Time-lapse electric resistivity in a stressed mangrove forest to image the role of the root zone in porewater salt distribution

    Science.gov (United States)

    Downs, C. M.; Krauss, K.; Kruse, S.

    2017-12-01

    The movement and storage of porewater salts is poorly understood in mangrove forests with limited surface water exchange between the forest and neighboring lagoon. These mangroves are often the most stressed, and have the most unfavorable salinity balance that often transition to mortality during extreme drought. A time-lapse resistivity survey was conducted in a stressed mangrove forest over a diel period. Resistivity is sensitive to the entire soil volume, including fine roots. The objective was to image changes in porewater salinity structures around both mangrove trees, where roots can be a prolific contributor to soil volume, and a salt pan with little or no vegetation. Throughout the diel period, salt pan conductivities remained relatively constant. The most significant temporal changes occur in the root zone around mangrove trees. Particularly interesting is a drop in resistivity (increased conductivity) at sunset when transpiration from individual trees decreases (or even ceases), potentially identifying a cumulative concentration of salts around the mangrove root zone after a full day of transpiration. The resistivity gradient decreases immediately after its peak at sunset, potentially identifying the consequences of hydraulic redistribution in diluting soils surrounding trees immediately after transpiration ceases. This is quicker than expected, and may imply a very strong and rapid eco-hydrological connection in the tree-facilitated salinity balance essential to their survival under the most salinity-stressed environments. At sunrise, resistivity increases, further suggesting dilution of salts via hydraulic redistribution of fresh water from the tree into the upper soil layers, or suggests an accumulation of salts within roots when presumably less water is moving through the trees. Repeated electric resistivity arrays provide spatial and temporal information about these salts and contribute to an overall understanding of how stressed mangrove forests

  5. Time-lapse resistivity measurements combined with soil water sampling to characterize solute movement in the unsaturated zone at Oslo airport, Gardermoen

    Science.gov (United States)

    Bloem, E.; French, H. K.; Binley, A.; Schotanus, D.; Eggen, G.

    2010-12-01

    Pollution of soils is a widespread problem and is an important part of the still to be implemented Soil Directive (EU). To improve risk assessment, monitoring, and treatment strategies for natural attenuation, we require a better understanding of the effect of soil heterogeneity on contaminant movement and methods for monitoring the effects of this heterogeneity at contaminated sites. Geophysical methods provide indirect measurements of subsurface properties over larger volumes than tradition techniques, and are potentially cost-efficient. However, the usefulness of any individual set of geophysical measurements (akin to a snapshot at one point in time) is severely limited by the problem of non-uniqueness or ambiguity when used to study contaminated sites, where the attendant processes vary in space and time. To make progress on soil contamination assessment and site characterization there is a strong need to integrate quasi field-scale, extensively instrumented tools, such as the multi-compartment sampler, with non-invasive (geophysical) and invasive (soil sampling, soil water sampling) methods. We illustrate this approach in an application to solute transport at Oslo airport, Norway. The impact of annual infiltration of large quantities of de-icing chemicals at Oslo airport, Gardermoen, represents common challenge for all airports with winter frost. It is also similar to the challenge posed by de-icing salt application along roads. At the research field station at Gardermoen, a degradable de-icing chemical and an inactive tracer were added to the snow cover prior to snowmelt and to the surface during an irrigation experiment performed after the snowmelt. In order to link geophysical measurements to solute transport processes in the unsaturated zone, time-lapse cross borehole resistivity as well as surface resistivity measurements were conducted at the same time as soil water samples were extracted. Measurements of soil temperature, and tension were also carried

  6. Monitoring the evolution and migration of a methane gas plume in an unconfined sandy aquifer using time-lapse GPR and ERT.

    Science.gov (United States)

    Steelman, Colby M; Klazinga, Dylan R; Cahill, Aaron G; Endres, Anthony L; Parker, Beth L

    2017-10-01

    Fugitive methane (CH 4 ) leakage associated with conventional and unconventional petroleum development (e.g., shale gas) may pose significant risks to shallow groundwater. While the potential threat of stray (CH 4 ) gas in aquifers has been acknowledged, few studies have examined the nature of its migration and fate in a shallow groundwater flow system. This study examines the geophysical responses observed from surface during a 72day field-scale simulated CH 4 leak in an unconfined sandy aquifer at Canadian Forces Base Borden, Canada, to better understand the transient behaviour of fugitive CH 4 gas in the subsurface. Time-lapse ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) were used to monitor the distribution and migration of the gas-phase and assess any impacts to groundwater hydrochemistry. Geophysical measurements captured the transient formation of a CH 4 gas plume emanating from the injector, which was accompanied by an increase in total dissolved gas pressure (P TDG ). Subsequent reductions in P TDG were accompanied by reduced bulk resistivity around the injector along with an increase in the GPR reflectivity along horizontal bedding reflectors farther downgradient. Repeat temporal GPR reflection profiling identified three events with major peaks in reflectivity, interpreted to represent episodic lateral CH 4 gas release events into the aquifer. Here, a gradual increase in P TDG near the injector caused a sudden lateral breakthrough of gas in the direction of groundwater flow, causing free-phase CH 4 to migrate much farther than anticipated based on groundwater advection. CH 4 accumulated along subtle permeability boundaries demarcated by grain-scale bedding within the aquifer characteristic of numerous Borden-aquifer multi-phase flow experiments. Diminishing reflectivity over a period of days to weeks suggests buoyancy-driven migration to the vadose zone and/or CH 4 dissolution into groundwater. Lateral and vertical CH 4

  7. Progress Report, December 2010: Improved Site Characterization And Storage Prediction Through Stochastic Inversion Of Time-Lapse Geophysical And Geochemical Data

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, A; Mcnab, W; Carle, S; Hao, Y; White, D; Johnson, J

    2010-12-17

    Over the last project six months, our project activities have concentrated on three areas: (1) performing a stochastic inversion of pattern 16 seismic data to deduce reservoir permeability, (2) development of the geochemical inversion strategy and implementation of associated software, and (3) completing the software implementation of TProGS and the geostatistical analysis that provides the information needed when using the software to produce realizations of the Midale reservoir. The report partially the following deliverables: D2: Model development: MCMC tool (synthetic fluid chemistry data); deliverable completed. D4: Model development/verification: MCMC tool (TProGS, field seismic/chemistry data) work product; deliverable requirements partially fulfilled. D5: Field-based single-pattern simulations work product; deliverable requirements partially fulfilled. When completed, our completed stochastic inversion tool will explicitly integrate reactive transport modeling, facies-based geostatistical methods, and a novel stochastic inversion technique to optimize agreement between observed and predicted storage performance. Such optimization will be accomplished through stepwise refinement of: (1) the reservoir model - principally its permeability magnitude and heterogeneity - and (2) geochemical parameters - primarily key mineral volume fractions and kinetic data. We anticipate that these refinements will facilitate significantly improved history matching and forward modeling of CO{sub 2} storage. Our tool uses the Markov Chain Monte Carlo (MCMC) methodology. Deliverable D1, previously submitted as a report titled ''Development of a Stochastic Inversion Tool To Optimize Agreement Between The Observed And Predicted Seismic Response To CO{sub 2} Injection/Migration in the Weyburn-Midale Project'' (Ramirez et al., 2009), described the stochastic inversion approach that will identify reservoir models that optimize agreement between the observed and

  8. Temporal changes of seismic velocity and anisotropy in the shallow crust induced by the 1999 October 22 M6.4 Chia-Yi, Taiwan earthquake

    Science.gov (United States)

    Chao, Kevin; Peng, Zhigang

    2009-12-01

    Observing temporal changes of material properties in the upper crust has been a long-sought goal within the geophysics community for many decades. A better quantification of temporal changes in the near-surface layers associated with nearby large earthquakes is crucial for improved understandings of rock rheology in the shallow crust, better characterization of site response, and accurate predictions of strong ground motions for future large earthquakes. We systematically analyse temporal changes of seismic velocity and anisotropy in the shallow crust in southwest Taiwan using local earthquakes recorded at a 200-m-deep borehole station CHY. This station is located directly above the hypocentre of the 1999 October 22, M6.4 Chia-Yi earthquake. Three-component seismograms recorded at this station show clear direct (upgoing) and surface-reflected (downgoing) P and S waves, and S-wave splitting signals. We use the time delays between the upgoing and downgoing waves in the autocorrelation functions as the proxies for the two-way traveltimes in the top 200 m. The S-wave traveltimes measured in two horizontal components increase by ~1-2 per cent at the time of Chia-Yi main shock, and followed by a logarithmic recovery, while the temporal changes of S-wave splitting and P-wave traveltimes are less than 1 per cent and are not statistically significant. We obtain similar results by grouping earthquakes into clusters according to their locations and waveform similarities. This suggests that the observed temporal changes are not very sensitive to the seismic ray paths below CHY, but are mostly controlled by the variation of material properties in the top 200 m of the crust. We propose that strong ground motions of the Chia-Yi main shock cause transient openings of fluid-filled microcracks and increases the porosity in the near-surface layers, followed by logarithemic recovery processes. No clear change in the delay times of the shear wave anisotropy is found following the main

  9. Numerical modelling of CO2 migration in saline reservoirs using geoelectric and seismic techniques - first results

    Science.gov (United States)

    Hagrey, S. A. Al; Strahser, M. H. P.; Rabbel, W.

    2009-04-01

    The research project "CO2 MoPa" (modelling and parameterisation of CO2 storage in deep saline formations for dimensions and risk analysis) has been initiated in 2008 by partners from different disciplines (e.g. geology, hydrogeology, geochemistry, geophysics, geomechanics, hydraulic engineering and law). It deals with the parameterisation of virtual subsurface storage sites to characterise rock properties, with high pressure-temperature experiments to determine in situ hydro-petrophysical and mechanical parameters, and with modelling of processes related to CCS in deep saline reservoirs. One objective is the estimation of the sensitivity and the resolution of reflection seismic and geoelectrical time-lapse measurements in order to determine the underground distribution of CO2. Compared with seismic, electric resistivity tomography (ERT) has lower resolution, but its permanent installation and continuous monitoring can make it an economical alternative or complement. Seismic and ERT (in boreholes) applications to quantify changes of intrinsic aquifers properties with time are justified by the velocity and resistivity decrease related to CO2 injection. Our numerical 2D/3D modelling reveals the capability of the techniques to map CO2 plumes and changes as a function of thickness, concentration, receiver/electrode configuration, aspect ratio and modelling and inversion constraint parameters. Depending on these factors, some configurations are favoured due to their better spatial resolution and lower artefacts. Acknowledgements This work has been carried out in the framework of "CO2 MoPa" research project funded by the Federal German Ministry of Education and Research (BMBF) and