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Sample records for kutsar avo trumm

  1. Nonbright spot AVO: Two examples

    SciTech Connect

    Ross, C.P.; Kinman, D.L.

    1994-12-31

    Utilization of amplitude-versus-offset (AVO) attribute sections such as the product of the normal incidence trace and gradient trace have been used extensively in bright spot (Class 3) AVO analysis and interpretation. However, while these sections have often worked well with Class 3 responses they are not reliable indicators of non-bright spot (Class 2) seismic anomalies. Analyzing Class 2 seismic data with AVO products will: (1) not detect the gas-charged reservoir because of near-zero acoustic impedance contrast between the sands and encasing shales, or (2) yield an incorrect (negative) AVO product if the normal incidence and gradient values are opposite in sign. Class 2 offset responses are divided into two sub-categories: those with phase reversals (Class 2p) and those without phase reversals (Class 2). An AVO procedure for these types of Class 2 anomalies is presented through two examples. The technique better exploits the nature of the prestack response, yielding a more definitive AVO attribute section, and the technique is adaptive to both Class 2 and Class 2p responses. When compared to a conventionally processed relative amplitude seismic section with characteristically low amplitude responses for near-zero acoustic impedance sands, this procedure clearly denotes the presence of gas-charged pore fluids within the reservoir.

  2. Nonbright-spot AVO: Two examples

    SciTech Connect

    Ross, C.P.; Kinman, D.L.

    1995-09-01

    The use of amplitude variation with offset (AVO) attribute sections such as the product of the normal incidence trace (A) and the gradient trace (B) have been used extensively in bright spot AVO analysis and interpretation. However, while these sections have often worked well with low acoustic impedance bright spot responses, they are not reliable indicators of nonbright-spot seismic anomalies. Analyzing nonbright-spot seismic data with common AVO attribute sections will: (1) not detect the gas-charged reservoir because of near-zero acoustic impedance contrast between the sands and encasing shales, or (2) yield an incorrect (negative) AVO product if the normal incidence and gradient values are opposite in sign. The authors divide nonbright-spot AVO offset responses into two subcategories: those with phase reversals and those without. An AVO analysis procedure for these anomalies is presented through two examples. The procedure exploits the nature of the prestack response, yielding a more definitive AVO attribute section, and this technique is adaptive to both subcategories of nonbright-spot AVO responses. This technique identifies the presence of gas-charged pore fluids within the reservoir when compared to a conventionally processed, relative amplitude seismic section with characteristically low amplitude responses for near-zero acoustic impedance contrast sands.

  3. Nonlinear Classification of AVO Attributes Using SVM

    NASA Astrophysics Data System (ADS)

    Zhao, B.; Zhou, H.

    2005-05-01

    A key research topic in reservoir characterization is the detection of the presence of fluids using seismic and well-log data. In particular, partial gas discrimination is very challenging because low and high gas saturation can result in similar anomalies in terms of Amplitude Variation with Offset (AVO), bright spot, and velocity sag. Hence, a successful fluid detection will require a good understanding of the seismic signatures of the fluids, high-quality data, and good detection methodology. Traditional attempts of partial gas discrimination employ the Neural Network algorithm. A new approach is to use the Support Vector Machine (SVM) (Vapnik, 1995; Liu and Sacchi, 2003). While the potential of the SVM has not been fully explored for reservoir fluid detection, the current nonlinear methods classify seismic attributes without the use of rock physics constraints. The objective of this study is to improve the capability of distinguishing a fizz-water reservoir from a commercial gas reservoir by developing a new detection method using AVO attributes and rock physics constraints. This study will first test the SVM classification with synthetic data, and then apply the algorithm to field data from the King-Kong and Lisa-Anne fields in Gulf of Mexico. While both field areas have high amplitude seismic anomalies, King-Kong field produces commercial gas but Lisa-Anne field does not. We expect that the new SVM-based nonlinear classification of AVO attributes may be able to separate commercial gas from fizz-water in these two fields.

  4. Direct hydrocarbon identification using AVO analysis in the Malay Basin

    SciTech Connect

    Lye, Y.C.; Yaacob, M.R. ); Birkett, N.E. ); Daneshvar, M.R. )

    1994-07-01

    Esso Production Malaysia Inc. and Petronas Carigali Sdn. Bhd. have been conducting AVO (amplitude versus offset) processing and interpretation since April 1991 in an attempt to identify hydrocarbon fluids predrill. The major part of this effort was in the PM-5, PM-8, and PM-9 contract areas where an extensive exploration program is underway. To date, more than 1000 km of seismic data have been analyzed using the AVO technique, and the results were used to support the drilling of more than 50 exploration and delineation wells. Gather modeling of well data was used to calibrate and predict the presence of hydrocarbon in proposed well locations. In order to generate accurate gather models, a geophysical properties and AVO database was needed, and great effort was spent in producing an accurate and complete database. This database is continuously being updated so that an experience file can be built to further improve the reliability of the AVO prediction.

  5. AVO inversion based on inverse operator estimation in trust region

    NASA Astrophysics Data System (ADS)

    Yin, Xing-Yao; Deng, Wei; Zong, Zhao-Yun

    2016-04-01

    Amplitude variation with offset (AVO) inversion is widely utilized in exploration geophysics, especially for reservoir prediction and fluid identification. Inverse operator estimation in the trust region algorithm is applied for solving AVO inversion problems in which optimization and inversion directly are integrated. The L1 norm constraint is considered on the basis of reasonable initial model in order to improve effciency and stability during the AVO inversion process. In this study, high-order Zoeppritz approximation is utilized to establish the inversion objective function in which variation of {{v}\\text{p}}/{{v}\\text{s}} with time is taken into consideration. A model test indicates that the algorithm has a relatively higher stability and accuracy than the damp least-squares algorithm. Seismic data inversion is feasible and inversion values of three parameters ({{v}\\text{p}},{{v}\\text{s}},ρ ) maintain good consistency with logging curves.

  6. Seafloor elastic parameters estimation based on AVO inversion

    NASA Astrophysics Data System (ADS)

    Liu, Yangting; Liu, Xuewei

    2015-12-01

    Seafloor elastic parameters play an important role in many fields as diverse as marine construction, seabed resources exploration and seafloor acoustics. In order to estimate seafloor elastic parameters, we perform AVO inversion with seafloor reflected seismic data. As a particular reflection interface, the seafloor reflector does not support S-waves and the elastic parameters change dramatically across it. Conventional approximations to the Zoeppritz equations are not applicable for the seafloor situation. In this paper, we perform AVO inversion with the exact Zoeppritz equations through an unconstrained optimization method. Our synthetic study proves that the inversion method does not show strong dependence on the initial model for both unconsolidated and semi-consolidated seabed situations. The inversion uncertainty of the elastic parameters increases with the noise level, and decreases with the incidence angle range. Finally, we perform inversion of data from the South China Sea, and obtain satisfactory results, which are in good agreement with previous research.

  7. AVO for one- and two-fracture set models

    USGS Publications Warehouse

    Chen, H.; Brown, R.L.; Castagna, J.P.

    2005-01-01

    A theoretical comparison is made of PP and PS angle-dependent reflection coefficients at the top of two fractured-reservoir models using exact, general, anisotropic reflection coefficients. The two vertical-fracture models are taken to have the same total crack density. The primary issue investigated is determination of the fracture orientation using azimuthal AVO analysis. The first model represents a single-fracture set and the second model has an additional fracture set oblique to the first set at an angle of 60??. As expected, the PP-wave anisotropy is reduced when multiple fracture sets are present, making the determination of orientation more difficult than for the case of a single-fracture set. Long offsets are required for identification of dominant fracture orientations using PP-wave AVO. PS-wave AVO, however, is quite sensitive to fracture orientations, even at short offsets. For multiple-fracture sets, PS signals can potentially be used to determine orientations of the individual sets. ?? 2005 Society of Exploration Geophysicists. All rights reserved.

  8. Factors facilitating or limiting the use of AVO for coal-bed methane

    SciTech Connect

    Peng, S.P.; Chen, H.J.; Yang, R.Z.; Gao, Y.F.; Chen, X.P.

    2006-07-15

    There are similarities and differences in employing amplitude variation with offset (AVO) to explore for gas-sand reservoirs, as opposed to coal-bed methane (CBM) reservoirs. The main similarity is that large Poisson's ratio contrasts, resulting in AVO gradient anomalies, are expected for both kinds of reservoirs. The main difference is that cleating and fracturing raise the Poisson's ratio of a coal seam as it improves its reservoir potential for CBM, while gas always lowers the Poisson's ratio of a sandstone reservoir. The top of gas sands usually has a negative AVO gradient, leading to a class one, two, or three anomaly depending on the impedance contrast with the overlying caprock. On the other hand, the top of a CBM reservoir has a positive AVO gradient, leading to a class four anomaly. Three environmental factors may limit the usage of AVO for CBM reservoirs: the smaller contrast in Poisson's ratio between a CBM reservoir and its surrounding rock, variations in the caprock of a specific CBM reservoir, and the fact that CBM is not always free to collect at structurally high points in the reservoir. However, other factors work in favor of using AVO. The strikingly high reflection amplitude of coal improves signal/noise ratio and hence the reliability of AVO measurements. The relatively simple characteristics of AVO anomalies make them easy to interpret. Because faults are known to improve the quality of CBM reservoirs, faults accompanied by AVO anomalies would be especially convincing. A 3D-AVO example offered in this paper shows that AVO might be helpful to delineate methane-rich sweet spots within coal seams.

  9. Iterative reweighted least M-estimate AVO inversion

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Zhang, Jiashu; Hu, Guangmin

    2015-04-01

    The l1 norm and its variants, such as the hybrid l1/l2 norm and the Huber norm, that are used to solve amplitude variation with offset (AVO) inversion optimisation problems, are mostly known to give a more robust solution than the classical least-squares (l2 norm) method by reducing the influence of outliers significantly, although never ignoring it. To deal with data having many outliers, biweight norm using iteratively reweighted least-squares (IRLS) as robust inversion method can improve robustness by ignoring outliers in computing the misfit measure. However, biweight norm uses a higher-order descending weighting on the measured data, which results in poor performance when dealing with the well measured data. Hampel's three-part redescending M-estimate function as robust measure could be considered as a three-part combination of the l2 norm and l1 norm with excluding outliers, which could perform better. This paper describes an iterative reweighted least M-estimate (IRLM) algorithm as a robust AVO inversion. The synthetic and field seismic data tests show that the IRLM algorithm gives far more robust model estimates than the conventional Huber norm and biweight norm.

  10. Inverse AVO problem for a stack of layers

    NASA Astrophysics Data System (ADS)

    Malovichko, Liliya

    2015-09-01

    The problem of estimating thin layered model parameters by amplitude variation with offset (AVO) inversion has been studied. The motivation was resolving of the thin layers in inverted prestack seismic data as it contains more information on elastic properties of the subsurface than poststack seismic data. In this paper, an algorithm for solving the prestack inverse AVO problem in the case of multilayered media is derived. This algorithm is based on iterative corrections to the parameters of the initial model which tend to minimise the misfits between observed and synthetic seismograms. The synthetic seismograms are calculated using the reflection-transmission (RT)-matrices method, assuming a plane-wave with respect to the source position. A regularised Gauss-type algorithm for the inversion of prestack seismic data has been used. A differential seismogram computation algorithm to characterise the sensitivity of the seismic signal to the variations of a model parameter was used. The derived solution of the inverse problem is constructed in the time domain. This gives a slight advantage because it allows for visual control of the solution process. One can monitor the amplitude reduction of the data residual (difference between observed and synthetic seismograms) during the iteration process. Numerical examples show the accuracy and efficiency of the method.

  11. Energy-weighted Amplitude Variation with Offset: A new AVO attribute for low impedance gas sands

    NASA Astrophysics Data System (ADS)

    Farfour, Mohammed; Yoon, Wang Jung; Jang, SeongHyung

    2016-06-01

    Amplitude Variation with Offset (AVO) is a technique that has been widely used as a reliable indicator of hydrocarbon expressions in seismic data. The technique uses mathematical approximations and approaches in order to estimate variations in seismic amplitude as a function of incidence angle, and related them to lithology and pore-fluids. In this study, a new AVO attribute is presented. The Energy-weighted AVO attribute uses Zoeppritz approximations and exploits the fact that hydrocarbon-bearing sediments show anomalous seismic responses relative to their backgrounds. The new AVO attribute emphasizes this hydrocarbon-associated effect and attenuates the background signal. In addition, the fact that the attribute integrates the signatures of conventional AVO attributes (intercept × gradient) with seismic data makes the discrimination of hydrocarbon anomalies from other anomalies caused by anomalous lithologies such as coal, carbonates or salt, straightforward. More interestingly, the new attribute can be applied to both prestack and poststack data. This indeed would solve several problems and difficulties encountered with prestack data, as prestack data are generally less readily available, and have a much lower signal to noise ratio. The process has been examined using synthetic data generated from Zoeppritz equations, and then applied to real prestack and poststack data. At all stages, promising results have been derived and the hydrocarbon effect and extent could be successfully predicted, also the AVO effect of hydrocarbons could be investigated even in the poststack data.

  12. Rotational Seismic AVO For Estimation Of Gas Hydrate Elastic Rock Properties

    NASA Astrophysics Data System (ADS)

    Barak, O.; Dvorkin, J. P.; Ronen, S.

    2013-12-01

    Gas hydrates represent a potential future energy resource. They are a form of water crystal that have a specific structure, and which are stabilized by the inclusion of methane gas molecules. The presence of a gas hydrate saturated layer can be seen in some seismic data as a result of the high impedance contrast between the gas hydrate layer and the underlying sediment. Several rock physics models exist to describe the way the gas hydrate is included in the host rock. To determine the best model, knowledge of several material parameters is required. Some of the material parameters can be estimated by observing the seismic AVO curve of the hydrate layer, which indicates P-wave reflectivity. However, the P-wave reflectivity is not very sensitive to the shear stiffness of the medium, which is one of the crucial parameters that helps clearly separate gas hydrates from their typical sedimentary surrounding. In this study we propose constructing converted-wave AVO curves from rotational seismic data acquired on the sea-bottom. Rotation data is a proxy for the reflected shear-wave energy. Since the shear-wave reflectivity is more dependent on the rigidity (or shear) modulus, we expect to see a greater sensitivity of the converted-wave AVO to spatial and temporal variations in rock-physics properties of the gas hydrate layer. Utilizing the rock-physics models and data from a well log near the Blake Outer Ridge where a hydrate layer is present, we constructed a 1.5D medium with effective elastic properties. We then use forward modeling to predict how a change in rock physics parameters may affect the AVO curve of the rotational-motion components recorded by rotation sensors, and compare the response to AVO obtained from the hydrophone component. We also compare the effect of layer thinning on the standard P-wave AVO versus on the rotational AVO. We conclude that rotational AVO is more sensitive to a change in the rock-physics parameters than is the conventional P-wave AVO

  13. Feasibility of time-lapse AVO and AVOA analysis to monitor compaction-induced seismic anisotropy

    NASA Astrophysics Data System (ADS)

    He, Y.-X.; Angus, D. A.; Yuan, S. Y.; Xu, Y. G.

    2015-11-01

    Hydrocarbon reservoir production generally results in observable time-lapse physical property changes, such as velocity increases within a compacting reservoir. However, the physical property changes that lead to velocity changes can be difficult to isolate uniquely. Thus, integrated hydro-mechanical simulation, stress-sensitive rock physics models and time-lapse seismic modelling workflows can be employed to study the influence of velocity changes and induced seismic anisotropy due to reservoir compaction. We study the influence of reservoir compaction and compartmentalization on time-lapse seismic signatures for reflection amplitude variation with offset (AVO) and azimuth (AVOA). Specifically, the time-lapse AVO and AVOA responses are predicted for two models: a laterally homogeneous four-layer dipping model and a laterally heterogeneous graben structure reservoir model. Seismic reflection coefficients for different offsets and azimuths are calculated for compressional (P-P) and converted shear (P-S) waves using an anisotropic ray tracer as well as using approximate equations for AVO and AVOA. The simulations help assess the feasibility of using time-lapse AVO and AVOA signatures to monitor reservoir compartmentalization as well as evaluate induced stress anisotropy due to changes in the effective stress field. The results of this study indicate that time-lapse AVO and AVOA analysis can be applied as a potential means for qualitatively and semi-quantitatively linking azimuthal anisotropy changes caused by reservoir production to pressure/stress changes.

  14. AVO in North of Paria, Venezuela: Gas methane versus condensate reservoirs

    SciTech Connect

    Regueiro, J.; Pena, A.

    1996-07-01

    The gas fields of North of Paria, offshore eastern Venezuela, present a unique opportunity for amplitude variations with offset (AVO) characterization of reservoirs containing different fluids: gas-condensate, gas (methane) and water (brine). AVO studies for two of the wells in the area, one with gas-condensate and the other with gas (methane) saturated reservoirs, show interesting results. Water sands and a fluid contact (condensate-water) are present in one of these wells, thus providing a control point on brine-saturated properties. The reservoirs in the second well consist of sands highly saturated with methane. Clear differences in AVO response exist between hydrocarbon-saturated reservoirs and those containing brine. However, it is also interesting that subtle but noticeable differences can be interpreted between condensate-and methane-saturated sands. These differences are attributed to differences in both in-situ fluid density and compressibility, and rock frame properties.

  15. Time-lapse AVO fluid inversion for dynamic reservoir characterization in Delhi Field, Louisiana

    NASA Astrophysics Data System (ADS)

    Putri, Indah Hermansyah

    In the development stage, CO2 injection is becoming more widely used in enhanced oil recovery (EOR). Delhi Oil Field is part of Phases XIII and XIV of the Reservoir Characterization Project (RCP) Colorado School of Mines. The focus of these phases is to monitor the effectiveness of the CO 2 injection in Delhi Field by using multicomponent time-lapse seismic data. In this study, I analyze the amplitude versus offset (AVO) response of the time-lapse P-wave seismic data in order to quantify the fluid probability in the field. RCP acquired four square miles of multicomponent time-lapse seismic in Delhi Field to characterize the field dynamically. RCP's two surveys, monitor 1 and monitor 2, were shot in 2010 and 2011 after the start of CO2 injection in November 2009. Time-lapse AVO modeling was performed. The modeling results show that both the top Tuscaloosa and Paluxy Formations are class III AVO, and change toward class IV AVO by increasing the CO2 saturation in the reservoir. In addition, the Paluxy Formation shows a consistent result between the synthetic and real data, however, the Tuscaloosa Formation is not consistent as it is affected by tuning. AVO fluid inversion (AFI) was performed on both the Tuscaloosa and Paluxy Formations in order to quantify the fluid probability in these formations. The inversion results are confirmed by the pseudo gamma ray model, the porosity model, the permeability model, the pressure model, and the production data. In the Tuscaloosa and Paluxy Formations, oil and CO2 are located in the good quality, high porosity, and high permeability sandstones. The presence of CO2 is also confirmed by the pressure interpretation. Furthermore, production data from both Tuscaloosa and Paluxy Formations confirm the fluid presence in the reservoir.

  16. Seismic characterization of fracture orientation in the Austin Chalk using azimuthal P-wave AVO

    NASA Astrophysics Data System (ADS)

    Al-Shuhail, Abdullatif Adulrahman

    The Austin Chalk is a naturally fractured reservoir. Horizontal drilling, to intersect more fractures, is the most efficient method to develop this reservoir. Information about the predominant fracture orientation in the subsurface is essential before horizontal drilling. This information may be provided by cores, well logs, outcrop, or seismic data. In this study, I apply the azimuthal P-wave AVO method suggested by Ruger and Tsvankin (1997) on 2-D P-wave seismic data in Gonzales County, Texas, in order to determine the fracture azimuth in the Austin Chalk. The data also include oil production from horizontal wells and various types of well logs from vertical wells in the study area. The raw seismic data was imaged through a processing sequence that preserved the relative changes of amplitudes with offset. The stacked sections of some seismic lines showed that the top of the Austin Chalk reflector is laterally inconsistent. This is interpreted as an indication of fractured zones in the subsurface. This interpretation was strengthened by well logs that indicated fracturing in nearby wells. The AVO gradient of every CDP in a seismic line was determined. The median AVO gradient of all the CDPs in a seismic line was chosen to represent the whole line. The median AVO gradients of the lines and their corresponding line azimuths were used repeatedly to solve the azimuthal AVO equation, of Ruger and Tsvankin (1997), for the fracture azimuth using a combination of three different lines every time. The resultant fracture-azimuth solutions clustered about two, nearly perpendicular, azimuths: N58E and S31E. To resolve the inherently ambiguous solutions, the results from the production and well log data were used. Since the production and well log data indicated the presence of NE-trending fractures, I chose the N58E direction as the fracture azimuth. This result agreed with the results of other studies in surrounding areas, using different methods, about the fracture azimuth

  17. AVO inversion for a nonwelded interface: estimating compliances of a fluid-filled fracture

    NASA Astrophysics Data System (ADS)

    Minato, Shohei; Ghose, Ranajit

    2016-04-01

    Though well-known for layer boundaries, the use of amplitude-versus-offset (AVO) variations for nonwelded boundaries like fractures is not yet investigated. Depending on the seismic wavelength used, fractures can be regarded as thin, compliant zones in rocks, in different scales. We explore the potential of multi-angle AVO inversion of P-P and P-S reflections from a fracture to estimate fracture properties. We conduct laboratory experiments to measure reflection responses of dry and wet fractures. The observed P-P reflections of the wet fracture and the fracture aperture are very well predicted by the nonwelded interface model. We invert the angle-dependent P-P reflectivity of the fracture to estimate both normal and tangential fracture compliances. The estimated value of the normal compliance is accurate, and it is also possible to obtain the value of the non-zero tangential compliance. We find that supplementing the information of converted P-S reflections in the AVO inversion greatly improves the estimate of the tangential compliance. The calculated compliance ratio clearly shows the existence of fluid in the fracture. This finding can be crucial for new applications in a wide range of scale - from earthquake seismology, deep and shallow seismic exploration, to nondestructive material testing.

  18. AVO correction for scalar waves in the case of a thinly layered reflector overburden

    SciTech Connect

    Widmaier, M.T.; Shapiro, S.A.; Hubral, P.

    1996-03-01

    The reflection response of a seismic target is significantly affected by a thinly layered overburden, which creates velocity anisotropy and a transmission loss by scattering attenuation. These effects must be taken into account when imaging a target reflector and when inverting reflection coefficients. Describing scalar wave (i.e., acoustic wave or SH-wave) propagation through a stack of thin layers by equivalent-medium theory provides a simple generalized O`Doherty-Anstey formula. This formulation is defined by a few statistical parameters that depend on the 1-D random fluctuations of the reflector overburden. The formula has been combined with well-known target-oriented and amplitude-preserving migration/inversion algorithms and amplitude variation with offset (AVO) analysis procedures. The application of these combined procedures is demonstrated for SH-waves in an elastic thinly-layered medium. These techniques offer a suitable tool to compensate for the thin-layer influence on traveltimes and amplitudes of seismic reflection data. The thin-layer sensitive AVO parameters (zero-offset amplitude and AVO gradient) of a target reflector can thus be better recovered.

  19. AVO inversion for a non-welded interface: estimating compliances of a fluid-filled fracture

    NASA Astrophysics Data System (ADS)

    Minato, Shohei; Ghose, Ranajit

    2016-07-01

    Though well known for layer boundaries, the use of amplitude-versus-offset (AVO) variations for non-welded boundaries like fractures is not yet investigated. Depending on the seismic wavelength used, fractures can be regarded as thin, compliant zones in rocks, in different scales. We explore the potential of multiangle AVO inversion of P-P and P-S reflections from a fracture to estimate fracture properties. We conduct laboratory experiments to measure reflection responses of dry and wet fractures. The observed P-P reflections of the wet fracture and the fracture aperture are very well predicted by the non-welded interface model. We invert the angle-dependent P-P reflectivity of the fracture to estimate both normal and tangential fracture compliances. The estimated value of the normal compliance is accurate, and it is also possible to obtain the value of the non-zero tangential compliance. We find that supplementing the information of converted P-S reflections in the AVO inversion greatly improves the estimate of the tangential compliance. The calculated compliance ratio clearly shows the existence of fluid in the fracture. This finding can be crucial for new applications in a wide range of scale-from earthquake seismology, deep and shallow seismic exploration, to non-destructive material testing.

  20. A Physical Study of Converted Wave AVO in a Fractured Reservoir

    NASA Astrophysics Data System (ADS)

    Chang, C. H.; Chang, Y. F.; Tsao, H. C.; Chang, J. W.

    2015-12-01

    Benefiting by the multicomponent seismic acquisition and processing techniques, the applications of converted waves in petroleum exploration is thus highlighted. A converted (C-) wave is initiated by a downward traveling P-wave that is converted on reflection to upcoming S-waves. Ascribing to its origins, C-wave takes the behaviors of P- and S-wave and becomes as one of the popular seismic attributes in the studies of a fractured reservoir. Making use of the scaled physical model, we aim on inspecting the azimuthal Amplitude Variation with Offset (AVO) of C-wave in a reservoir of vertically aligned fractures. In order to facilitate the objective of this study, reflection experiments were carried out on the orthogonal plane of a Horizontal Transversely Isotropic (HTI) model which is created to simulate a fractured reservoir. In laboratory manipulation, acoustic energy is triggered by a P-type transducer and the reflected energy is received an S-type transducer to detect the reflected energy, i.e. C-waves, originating by mode conversion. From fracture strike to facture normal, end-on shooting reflections were acquired from seven different directions. The angular interval in between the successive observation is 15 degrees. While viewing into the reflection profiles, events of P-, C1- and C2-waves can be readily identified. In the acquired profiles, the P-wave AVO is clearly observed and the phenomenon of C-wave splitting is revealed by the separation of traveltime-distance curves of C1- and C2-waves. However, it is aware of that the C-wave amplitudes are not simply varied or attenuated with offset in each observation. The complicated behaviors of C-wave AVO could be caused by the amount of energy, which is incident angle dependent, in reflected S-waves. Hence, our results indicate that the azimuthal C-wave AVO might not be a reliable seismic signature which can be used to delineate the fracture orientation of a fractured reservoir.

  1. The influence of fluid-sensitive dispersion and attenuation on AVO analysis

    NASA Astrophysics Data System (ADS)

    Chapman, Mark; Liu, Enru; Li, Xiang-Yang

    2006-10-01

    Analysis of seismic data suggests that hydrocarbon deposits are often associated with higher than usual values of attenuation, but this is generally ignored during amplitude-versus-offset (AVO) analysis. The effect can be modelled with equivalent medium theory based on the squirt flow concept, but the excess attenuation is associated with strong velocity dispersion. Consequently, when we study reflections from the interface between such an equivalent medium and an elastic overburden we find that the reflection coefficient varies with frequency. The impact of this variation depends on the AVO behaviour at the interface; class I reflections tend to be shifted to higher frequency while class III reflections have their lower frequencies amplified. We calculate synthetic seismograms for typical models using the reflectivity method for materials with frequency dependent velocities and attenuations, and find that these effects are predicted to be detectable on stacked data. Two field data sets show frequency anomalies similar to those predicted by the analysis, and we suggest that our modelling provides a plausible explanation of the observations.

  2. Weighted stacking of seismic AVO data using hybrid AB semblance and local similarity

    NASA Astrophysics Data System (ADS)

    Deng, Pan; Chen, Yangkang; Zhang, Yu; Zhou, Hua-Wei

    2016-04-01

    The common-midpoint (CMP) stacking technique plays an important role in enhancing the signal-to-noise ratio (SNR) in seismic data processing and imaging. Weighted stacking is often used to improve the performance of conventional equal-weight stacking in further attenuating random noise and handling the amplitude variations in real seismic data. In this study, we propose to use a hybrid framework of combining AB semblance and a local-similarity-weighted stacking scheme. The objective is to achieve an optimal stacking of the CMP gathers with class II amplitude-variation-with-offset (AVO) polarity-reversal anomaly. The selection of high-quality near-offset reference trace is another innovation of this work because of its better preservation of useful energy. Applications to synthetic and field seismic data demonstrate a great improvement using our method to capture the true locations of weak reflections, distinguish thin-bed tuning artifacts, and effectively attenuate random noise.

  3. Geologic data management at AVO: building authoritative coverage with radical availability (Invited)

    NASA Astrophysics Data System (ADS)

    Cameron, C.; Snedigar, S. F.; Nye, C. J.

    2009-12-01

    In 2002, the Alaska Volcano Observatory (AVO) began creating the Geologic Database of Information on Volcanoes in Alaska (GeoDIVA) to create a system that contains complete, flexible, timely, and accurate geologic and geographic information on Pleistocene and younger volcanoes in Alaska. This system was primarily intended to be a tool for scientific investigation, crisis response, and public information - delivered in a dynamic, digital format to both internal and external users. It is now the back-end of the AVO public website. GeoDIVA does not interface with our daily monitoring activities, however -- seismic and satellite data are handled by different database efforts. GeoDIVA also doesn’t store volcanic unrest data, although we hope WOVOdat will. GeoDIVA does include modules for the following datasets: bibliography (every subsequent piece of data in GeoDIVA is tied to a reference), basic volcano information (~137 edifices), historical eruption history information (~550 events), images (~17,000), sample information (~4400), geochemistry (~1500; population in progress), petrography (very early stages of data creation), sample storage (~14,000), and Quaternary vent information (~1200 vents). Modules in progress include GIS data, tephra data, and geochronologic data. In recent years, we have been doing maintenance work on older modules (for example, adding new references to the bibliography, and creating new queries and data fields in response to user feedback) as well as developing, designing, and populating new modules. Population can be quite time consuming, as there are no pre-compiled comprehensive existing sources for most information on Alaskan volcanoes, and we carefully reference each item. Newer modules also require more complex data arrangements than older modules. To meet the needs of a diverse group of users on widely varying computer platforms, GeoDIVA data is primarily stored in a MySQL DBMS; PostGIS/PostgreSQL are currently used to store and

  4. Simultaneous Joint Inversion of Seismic AVO and Controlled Source Electromagnetic Data by Direct Estimation of Common Parameter Structure

    NASA Astrophysics Data System (ADS)

    Lien, M.

    2012-12-01

    We are concerned with the inverse problem of identifying changes in saturation for monitoring of underground reservoirs with application to CO2 sequestration and oil production monitoring. The inverse problem is at the outset ill-posed, where non-uniqueness and instability issues can lead to large uncertainties in the resulting parameter estimates. Constraining the inversion with a higher degree of information by combining information from different data sets will be important to improve the quality of the model calibration and thereby the reliability of the resulting reservoir predictions. For this, the simultaneous joint inversion of seismic AVO and controlled source electromagnetic (CSEM) data is considered. With simultaneous joint inversion, one secures that the final result from the inversion honors all available data. AVO and CSEM represent different sources of information. The seismic signals provide information about the elastic properties of the reservoir with relatively high spatial resolution, whereas CSEM data probe the electric properties of the subsediments at the extreme low frequency limit. Hence, the coupling of the two data types is not trivial. An increasingly popular approach for simultaneous joint inversion of disparate data sets is structure-coupled joint inversion. Here the coupling of the data sets is obtained by imposing structural dependency between the different geophysical model parameters (i.e. the elastic and electric properties of the reservoir). The idea is that some of the main property changes in the different model parameters are likely to occur over the same interfaces/structures representing e.g. changes in lithology or fluid saturation. We propose a novel approach for structure-coupled joint inversion, where the coupling of the different data sets is obtained by facilitating for estimation of parameter structure directly. The approach is based on a generic method for parameter representation providing a joint relation to a

  5. Formation, structure and magnetism of the metastable defect fluorite phases AVO{sub 3.5+x} (A=In, Sc)

    SciTech Connect

    Shafi, Shahid P.; Lundgren, Rylan J.; Cranswick, Lachlan M.D.; Bieringer, Mario

    2007-12-15

    We report the preparation and stability of ScVO{sub 3.5+x} and the novel phase InVO{sub 3.5+x}. AVO{sub 3.5+x} (A=Sc, In) defect fluorite structures are formed as metastable intermediates during the topotactic oxidation of AVO{sub 3} bixbyites. The oxidation pathway has been studied in detail by means of thermogravimetric/differential thermal analysis and in-situ powder X-ray diffraction. The oxidation of the bixbyite phase follows a topotactic pathway at temperatures between 300 and 400 deg. C in air/carbon dioxide. The range of accessible oxygen stoichiometries for the AVO{sub 3.5+x} structures following this pathway are 0.00{<=}x{<=}0.22. Rietveld refinements against powder X-ray and neutron data revealed that InVO{sub 3.54} and ScVO{sub 3.70} crystallize in the defect fluorite structure in space group Fm-3 m (227) with a=4.9863(5) and 4.9697(3)A, respectively with A{sup 3+}/V{sup 4+} disorder on the (4a) cation site. Powder neutron diffraction experiments indicate clustering of oxide defects in all samples. Bulk magnetic measurements showed the presence of V{sup 4+} and the absence of magnetic ordering at low temperatures. Powder neutron diffraction experiments confirmed the absence of a long range ordered magnetic ground state. - Graphical abstract: Topotactic oxidation of AVO{sub 3} bixbyite to AVO{sub 3.5} defect fluorite structure followed by in-situ powder X-ray diffraction. The upper structural diagram shows a six coordinated (A/V)-O{sub 6} fragment in bixbyite, the lower structure illustrates the same seven-fold coordinated (A/V)-O{sub 7} cubic environment in the defect fluorite structure.

  6. The influence of the Goos-Hänchen effect on seismic data processing and AVO in attenuating media

    NASA Astrophysics Data System (ADS)

    Wang, Zhiyong

    2015-11-01

    The Goos-Hänchen (GH) effect induced by the total reflection of an incident beam of P-wave from a low-impedance medium to a high-impedance medium at near- and post-critical angles was theoretically simulated and discussed. For both PP- and PSV-waves, there may be large GH shifts (GHS) and penetration depths (PD) for both lossless and attenuating media. As the Q-factor increases, or the frequency of the seismic wave decreases, the GH effect is increased. However, in attenuating media, there may be non-zero GHS and PD at all non-zero incident angles, not just post-critical angles. GHS may be either positive or negative, while PD is positive only. Compared to the Q-factor in the incident medium, the Q-factor in the transmission medium may play a more dominant role in the determination of reflection coefficients, GHS, and PD. The GH-induced normal moveout (NMO) discrepancy of the PSV-wave may be larger than that of the PP-wave. Due to the GH effect, there may be an angle discrepancy (at fixed offset) between the GH-modified incident angle and the traditional incident angle. In addition, the GH effect at a given offset may produce two or three reflected waves, from different incident angles. These results suggest that, within their assumptions, the GH effect may lead to errors in NMO estimates and the vertical location of the reflector. Furthermore, there may be errors in offsets, incident angles, and reflection amplitudes, in the analyses of the amplitude variation with offset (AVO). These GH effects might be more important for seismic data at fixed offsets and shallow layers, and for sonic log data, which might fall into the post-critical angle regime. Therefore, there may be a necessity to take into account the GH effect in the interpretation of wide-angle reflection data in NMO and AVO analyses.

  7. Modeling CO2 vertical migration based on seismic frequency-dependent AVO responses

    NASA Astrophysics Data System (ADS)

    Li, Bonan; Liu, Cai; Lu, Qi; Pang, Shuo

    2016-04-01

    Injection of CO2 into a geological subsurface will cause seismic dispersion and attenuation, which will change with the migration of the CO2 plume. Therefore, temporal attenuation changes from the seismic section with the CO2 plume can provide additional information about CO2 storage, migration, and possible leakage. The frequency-dependent amplitude variation with offset (FDAVO) attribute, as a seismic characteristic, which quantifies frequency-dependent anomalies from various kinds of sources, is widely applied in fields of hydrocarbon indication and fluid identification. In this work we aim to investigate the potential of the FDAVO attribute as a monitoring tool during the process of CO2 migration. We combine the Buckley-Leverett equation and the patchy-saturation model to simulate the substitution process. We then apply a novel tool, the FDAVO inversion method, to estimate the dispersion level at the target interface. What is more, the characteristic of the frequency-dependent attribute versus time is studied for the first time. The result of the numerical simulation reveals that: (1) caused by CO2 injection, there is significant dispersion and attenuation within the seismic band; (2) the level of dispersion reflects the migration of CO2 plume; (3) dispersion anomalies are well quantified by the inverted FDAVO attributes, which can be utilized to characterize the vertical distribution of the CO2 plume.

  8. CHARACTERIZATION OF AN AQUITARD AND DIRECT DETECTION OF LNAPL AT HILL AIR FORCE BASE USING GPR AVO AND MIGRATION VELOCITY ANALYSES

    EPA Science Inventory

    Large quantities of non-aqueous phase liquids (NAPL) contaminate the near surface sediments at Operable Unit 1 (OU1), Hill Air Force Base (HAFB), Utah. In October 2000, a 3D, multi-offset GPR survey was acquired at OU1 with two objectives: 1) to i...

  9. 2011 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Maharrey, J. Zebulon; Neal, Christina A.

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near three separate volcanic centers in Alaska during 2011. The year was highlighted by the unrest and eruption of Cleveland Volcano in the central Aleutian Islands. AVO annual summaries no longer report on activity at Russian volcanoes.

  10. Alaska Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Murray, Tom; Read, Cyrus

    2008-01-01

    Steam plume from the 2006 eruption of Augustine volcano in Cook Inlet, Alaska. Explosive ash-producing eruptions from Alaska's 40+ historically active volcanoes pose hazards to aviation, including commercial aircraft flying the busy North Pacific routes between North America and Asia. The Alaska Volcano Observatory (AVO) monitors these volcanoes to provide forecasts of eruptive activity. AVO is a joint program of the U.S. Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Augustine volcano and AVO at http://www.avo.alaska.edu.

  11. Twenty years of Alaska Volcano Observatory's contributions to seismology

    NASA Astrophysics Data System (ADS)

    Dixon, J. P.; McNutt, S. R.; Power, J. A.; West, M.

    2008-12-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute at the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys observed its 20th anniversary in 2008. The AVO seismic network, inherited from AVO partners in 1988, consisted of three small-aperture subnetworks on Mount Spurr, Redoubt Volcano and Augustine Volcano and regional stations for a total of 23 short-period instruments (two with three-components). Twenty years later, the AVO network has expanded to 192 stations (23 three-component short-period, and 15 broadband) on 33 volcanoes spanning 2500 km across the Aleutian arc in one of the most remote and challenging environments in the world. The AVO seismic network provides for a unique data set. Within the seismically active Aleutian Arc, there are instrumented volcanoes which exhibit a variety of chemical compositions and eruptive styles. With each individual volcanic center similarly instrumented and all data analyzed in a consistent manner AVO has produced a data set suitable for making seismic comparisons across a wide suite of volcanoes. In twenty years, the AVO has captured data sets for eruptions at Augustine, Kasatochi, Okmok, Pavlof, Redoubt, Shishaldin, Spurr, and Venianinof. AVO data set also includes several volcanic-tectonic swarms, most notably at Akutan, Iliamna, Mageik, Martin, Shishaldin, and Tanaga. This broad approach to volcano seismology has led to a better understanding of precursory earthquake swarms, variations in background rates, triggered seismicity, the structure of volcanoes, volcanic tremor and deep long period earthquakes, among numerous other topics. The AVO also incorporates data from seismic stations operated by both the Alaska Earthquake Information Center and West Coast and Alaska Tsunami Warning Center to help locate some of the 70,000 earthquakes in the AVO catalog. In exchange AVO provides dense seismic data from the

  12. [A blind bicycle repair man at the Stedelijk Museum: the exhibition and congress 'labour for the disabled' of 1928].

    PubMed

    Hermans, H J E; Schmidt, S H

    2002-01-01

    In the 1920's concern about the rising number of disabled unemployed urban poor led to the founding of the AVO (Dutch organization for labour care for the disabled) in 1927. The AVO presented the problem of the vulnerability of the physically and mentally disabled in the labour market as a matter of collective responsibility. At the Amsterdam AVO congress of 1928 expert contributors discussed the economic, social and medical aspects of disability and work. Simultaneously, a museum exhibition aimed at arousing the interest of the general public and at promoting a more understanding attitude towards the disabled. Though the twofold AVO manifestation raised an immediate favourable general response and the subject was put on the political agenda, the subsequent economic recession and war forestalled concrete measures. Essentially it was the first public debate on disability in the Netherlands. PMID:12683366

  13. 77 FR 34400 - Agency Information Collection Activities: Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-11

    ... forecasts as the ash cloud moves downwind. Retrospectively these reports will enable USGS to improve their... report database will help AVO track eruption clouds and associated fallout downwind. These reports...

  14. Public outreach and communications of the Alaska Volcano Observatory during the 2005-2006 eruption of Augustine Volcano: Chapter 27 in The 2006 eruption of Augustine Volcano, Alaska

    USGS Publications Warehouse

    Adleman, Jennifer N.; Cameron, Cheryl E.; Snedigar, Seth F.; Neal, Christina A.; Wallace, Kristi L.

    2010-01-01

    The AVO Web site, with its accompanying database, is the backbone of AVO's external and internal communications. This was the first Cook Inlet volcanic eruption with a public expectation of real-time access to data, updates, and hazards information over the Internet. In March 2005, AVO improved the Web site from individual static pages to a dynamic, database-driven site. This new system provided quick and straightforward access to the latest information for (1) staff within the observatory, (2) emergency managers from State and local governments and organizations, (3) the media, and (4) the public. From mid-December 2005 through April 2006, the AVO Web site served more than 45 million Web pages and about 5.5 terabytes of data.

  15. 1995 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.

    1996-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity (SVA) at 6 volcanic centers in 1995: Mount Martin (Katmai Group), Mount Veniaminof, Shishaldin, Makushin, Kliuchef/Korovin, and Kanaga. In addition to responding to eruptive activity at Alaska volcanoes, AVO also disseminated information for the Kamchatkan Volcanic Eruption Response Team (KVERT) on the 1995 eruptions of 2 Russian volcanoes: Bezymianny and Karymsky. This report summarizes volcanic activity in Alaska during 1995 and the AVO response, as well as information on the 2 Kamchatkan eruptions. Only those reports or inquiries that resulted in a "significant" investment of staff time and energy (here defined as several hours or more for reaction, tracking, and follow-up) are included. AVO typically receives dozens of phone calls throughout the year reporting steaming, unusual cloud sightings, or eruption rumors. Most of these are resolved quickly and are not tabulated here as part of the 1995 response record.

  16. 1994 Volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; Doukas, Michael P.; McGimsey, Robert G.

    1995-01-01

    During 1994, the Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, or false alarms at nine volcanic centers-- Mount Sanford, Iliamna, the Katmai group, Kupreanof, Mount Veniaminof, Shishaldin, Makushin, Mount Cleveland and Kanaga (table 1). Of these volcanoes, AVO has a real time, continuously recording seismic network only at Iliamna, which is located in the Cook Inlet area of south-central Alaska (fig. 1). AVO has dial-up access to seismic data from a 5-station network in the general region of the Katmai group of volcanoes. The remaining unmonitored volcanoes are located in sparsely populated areas of the Wrangell Mountains, the Alaska Peninsula, and the Aleutian Islands (fig. 1). For these volcanoes, the AVO monitoring program relies chiefly on receipt of pilot reports, observations of local residents and analysis of satellite imagery.

  17. 2013 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Dixon, James P.; Cameron, Cheryl; McGimsey, Robert G.; Neal, Christina A.; Waythomas, Chris

    2015-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, volcanic unrest or suspected unrest, and seismic events at 18 volcanic centers in Alaska during 2013. Beginning with the 2013 AVO Summary of Events, the annual description of the AVO seismograph network and activity, once a stand-alone publication, is now part of this report. Because of this change, the annual summary now contains an expanded description of seismic activity at Alaskan volcanoes. Eruptions occurred at three volcanic centers in 2013: Pavlof Volcano in May and June, Mount Veniaminof Volcano in June through December, and Cleveland Volcano throughout the year. None of these three eruptive events resulted in 24-hour staffing at AVO facilities in Anchorage or Fairbanks.

  18. 1996 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.

    1997-01-01

    During 1996, the Alaska Volcano Observatory (AVO) responded to eruptive activity, anomalous seismicity, or suspected volcanic activity at 10 of the approximately 40 active volcanic centers in the state of Alaska. As part of a formal role in KVERT (the Kamchatkan Volcano Eruption Response Team), AVO staff also disseminated information about eruptions and other volcanic unrest at six volcanic centers on the Kamchatka Peninsula and in the Kurile Islands, Russia.

  19. 2010 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; Herrick, Julie; Girina, O.A.; Chibisova, Marina; Rybin, Alexander; McGimsey, Robert G.; Dixon, Jim

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest or suspected unrest at 12 volcanic centers in Alaska during 2010. The most notable volcanic activity consisted of intermittent ash emissions from long-active Cleveland volcano in the Aleutian Islands. AVO staff also participated in hazard communication regarding eruptions or unrest at seven volcanoes in Russia as part of an ongoing collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  20. Preparation and characterization of cosmeceutical liposomes loaded with avobenzone and arbutin.

    PubMed

    Liu, Jun-Jen; Nazzal, Sami; Chang, Tzu-Shan; Tsai, Tsuimin

    2013-01-01

    The objective of this study was to develop and characterize a liposome delivery system coencapsulating two cosmeceutical ingredients, avobenzone (AVO) and arbutin (AR). Two different liposome preparation methods, that is, thin film hydration and reverse-phase evaporation, were evaluated. To obtain the optimal formulation, various ratios of lipid to AVO or AR were tested. The effects of liposome formulation and preparation method on particle size, entrapment efficiency (EE), and skin permeation rate were studied. The mean particle size of the liposome formulations obtained by the thin film hydration method was smaller than that obtained by the reverse-phase evaporation method. The EE of AR and AVO in liposomes prepared by the thin film method, however, was lower than that prepared by the reverse-phase evaporation method. No differences in membrane permeation were observed between the two preparation methods. A large portion of AR permeated through the membrane into the receptor chamber. On the other hand, AVO remained in the donor chamber or accumulated in the membrane. The results of this study revealed that liposomes are a promising delivery system for coencapsulated AR and AVO. Liposomes may aid in retaining the sunscreen (AVO) at the surface of the skin for sun protection meanwhile facilitating the penetration of the whitening agent (AR) into the deeper layers of the skin for whitening effect. PMID:23449127

  1. Programmed Speed Reduction Enables Aortic Valve Opening and Increased Pulsatility in the LVAD-Assisted Heart.

    PubMed

    Tolpen, Sam; Janmaat, Jochem; Reider, Claudine; Kallel, Faouzi; Farrar, David; May-Newman, Karen

    2015-01-01

    Aortic valve opening (AVO) during left ventricular assist device (LVAD) support aids in preventing valve fusion, incompetence, and thrombosis. The programmed low speed algorithm (PLSA) allows AVO intermittently by reducing continuous motor speed during a dwell time. AVO and hemodynamics in the LVAD-assisted heart were measured using a HeartMate II (Thoratec Corporation, Pleasanton, CA) LVAD with a PLSA controller in a mock circulatory loop. Left ventricle and aortic pressures, LVAD, and total aortic flow were measured during pre-LVAD, non-PLSA and PLSA combinations of cardiac function, and LVAD speed. The low cardiac setting corresponded to a pre-LVAD cardiac output of 2.8 L/min, stroke volume of 40 ml, and ejection fraction of 22%; the medium setting produced values of 3.5 L/min, 50 ml, and 28%, respectively. Results show that the PLSA controller set at 10 krpm, dropping to 7 krpm for dwell time of 6 s, adequately produced AVO for all tested cardiac functions with only minimal changes in cardiac output. However, AVO frequency was independent of opening area and systolic duration, which both decreased with increasing LVAD support. Furthermore, aortic pulsatility index quadrupled in the aortic root and doubled in the distal aorta during PLSA conditions, providing evidence that AVO and blood mixing are enabled by PLSA control at the appropriate speed. PMID:25961849

  2. Alaska Volcano Observatory Seismic Network Data Availability

    NASA Astrophysics Data System (ADS)

    Dixon, J. P.; Haney, M. M.; McNutt, S. R.; Power, J. A.; Prejean, S. G.; Searcy, C. K.; Stihler, S. D.; West, M. E.

    2009-12-01

    The Alaska Volcano Observatory (AVO) established in 1988 as a cooperative program of the U.S. Geological Survey, the Geophysical Institute at the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, monitors active volcanoes in Alaska. Thirty-three volcanoes are currently monitored by a seismograph network consisting of 193 stations, of which 40 are three-component stations. The current state of AVO’s seismic network, and data processing and availability are summarized in the annual AVO seismological bulletin, Catalog of Earthquake Hypocenters at Alaska Volcanoes, published as a USGS Data Series (most recent at http://pubs.usgs.gov/ds/467). Despite a rich seismic data set for 12 VEI 2 or greater eruptions, and over 80,000 located earthquakes in the last 21 years, the volcanic seismicity in the Aleutian Arc remains understudied. Initially, AVO seismic data were only provided via a data supplement as part of the annual bulletin, or upon request. Over the last few years, AVO has made seismic data more available with the objective of increasing volcano seismic research on the Aleutian Arc. The complete AVO earthquake catalog data are now available through the annual AVO bulletin and have been submitted monthly to the on-line Advanced National Seismic System (ANSS) composite catalog since 2008. Segmented waveform data for all catalog earthquakes are available upon request and efforts are underway to make this archive web accessible as well. Continuous data were first archived using a tape backup, but the availability of low cost digital storage media made a waveform backup of continuous data a reality. Currently the continuous AVO waveform data can be found in several forms. Since late 2002, AVO has burned all continuous waveform data to DVDs, as well as storing these data in Antelope databases at the Geophysical Institute. Beginning in 2005, data have been available through a Winston Wave Server housed at the USGS in

  3. In vitro cytotoxicity of Artemisia vulgaris L. essential oil is mediated by a mitochondria-dependent apoptosis in HL-60 leukemic cell line

    PubMed Central

    2014-01-01

    Background The essential oil (EO) of Artemisia vulgaris L. has been traditionally used worldwide for treating a large number of diseases. Although major components in A. vulgaris EO have been shown to inhibit growth of different cancer cells, as pure compounds or part of other plants extracted oil, no information is known about its anti-proliferative activities. Therefore, the current investigation has evaluated the toxicity of the plant extracted oil from buds (AVO-b) and leaves (AVO-l) and characterized their growth inhibitory effects on cancer cells. Methods AVO-b and AVO-l from A. vulgaris L. were extracted by hydrodistillation, and their effect on the viability of human HL-60 promyelocytic leukemia and various other cancer cell lines was tested using MTT assay. Flow cytometric analysis of apoptosis, DNA fragmentation assay, caspases enzymatic activities and Western blotting were used to determine the apoptotic pathway triggered by their action on HL-60 cells. Results Low concentrations of AVO-b and AVO-l inhibited the growth of HL-60 cells in a dose- and time-dependent manner. Employing flow cytometric, DNA fragmentation and caspase activation analyses, demonstrated that the cytotoxic effect of the oils is mediated by a caspase-dependent apoptosis. Kinetic studies in the presence and absence specific caspase inhibitors showed that activation of caspase-8 was dependent and subsequent to the activation of caspases-9 and -3. In addition, the essential oil caused a disruption of the mitochondrial transmembrane potential (ΔΨm), increased the release of cytochrome c to the cytosol, and altered the expression of certain members of Bcl-2 family (Bcl-2, Bax and Bid), Apaf-1 and XIAP. Interestingly, low doses of AVO-b and AVO-1 also induced apoptosis in various cancer cell lines, but not in noncancerous cells. Conclusions The results demonstrate that the EO-induced apoptosis in HL-60 cells is mediated by caspase-dependent pathways, involving caspases-3, -9, and -8

  4. Response of the Alaska Volcano Observatory to Public Inquiry Concerning the 2006 Eruption of Augustine Volcano, Cook Inlet, Alaska

    NASA Astrophysics Data System (ADS)

    Adleman, J. N.

    2006-12-01

    The 2006 eruption of Augustine Volcano provided the Alaska Volcano Observatory (AVO) with an opportunity to test its newly renovated Operations Center (Ops) at the Alaska Science Center in Anchorage. Because of the demand for interagency operations and public communication, Ops became the hub of Augustine monitoring activity, twenty-four hours a day, seven days a week, from January 10 through May 19, 2006. During this time, Ops was staffed by 17 USGS AVO staff, and over two dozen Fairbanks-based AVO staff from the Alaska Department of Geological and Geophysical Surveys and the University of Alaska Fairbanks Geophysical Institute and USGS Volcano Hazards Program staff from outside Alaska. This group engaged in communicating with the public, media, and other responding agencies throughout the eruption. Before and during the eruption, reference sheets - ;including daily talking - were created, vetted, and distributed to prepare staff for questions about the volcano. These resources were compiled into a binder stationed at each Ops phone and available through the AVO computer network. In this way, AVO was able to provide a comprehensive, uniform, and timely response to callers and emails at all three of its cooperative organizations statewide. AVO was proactive in scheduling an Information Scientist for interviews on-site with Anchorage television stations and newspapers several times a week. Scientists available, willing, and able to speak clearly about the current activity were crucial to AVO's response. On January 19, 2006, two public meetings were held in Homer, 120 kilometers northeast of Augustine Volcano. AVO, the West Coast Alaska Tsunami Warning Center, and the Kenai Peninsula Borough Office of Emergency Management gave brief presentations explaining their roles in eruption response. Representatives from several local, state, and federal agencies were also available. In addition to communicating with the public by daily media interviews and phone calls to Ops

  5. 1997 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Wallace, Kristi L.

    1999-01-01

    The Alaska Volcano Observatory (AVO) monitors over 40 historically active volcanoes along the Aleutian Arc. Twenty are seismically monitored and for the rest, the AVO monitoring program relies mainly on pilot reports, observations of local residents and ship crews, and daily analysis of satellite images. In 1997, AVO responded to eruptive activity or suspect volcanic activity at 11 volcanic centers: Wrangell, Sanford, Shrub mud volcano, Iliamna, the Katmai group (Martin, Mageik, Snowy, and Kukak volcanoes), Chiginagak, Pavlof, Shishaldin, Okmok, Cleveland, and Amukta. Of these, AVO has real-time, continuously recording seismic networks at Iliamna, the Katmai group, and Pavlof. The phrase “suspect volcanic activity” (SVA), used to characterize several responses, is an eruption report or report of unusual activity that is subsequently determined to be normal or enhanced fumarolic activity, weather-related phenomena, or a non-volcanic event. In addition to responding to eruptive activity at Alaska volcanoes, AVO also disseminated information for the Kamchatkan Volcanic Eruption Response Team (KVERT) about the 1997 activity of 5 Russian volcanoes--Sheveluch, Klyuchevskoy, Bezymianny, Karymsky, and Alaid (SVA). This report summarizes volcanic activity and SVA in Alaska during 1997 and the AVO response, as well as information on the reported activity at the Russian volcanoes. Only those reports or inquiries that resulted in a “significant” investment of staff time and energy (here defined as several hours or more for reaction, tracking, and follow-up) are included. AVO typically receives dozens of reports throughout the year of steaming, unusual cloud sightings, or eruption rumors. Most of these are resolved quickly and are not tabulated here as part of the 1997 response record.

  6. Photostability evaluation of five UV-filters, trans-resveratrol and beta-carotene in sunscreens.

    PubMed

    Freitas, Juliana Vescovi; Lopes, Norberto Peporine; Gaspar, Lorena Rigo

    2015-10-12

    Trans-resveratrol (RES) is used in cosmetic formulations and beta-carotene (BTC) is a classical sunscreen antioxidant, but their photostability in sunscreens, a property directly correlated to performance and safety has not been addressed in the literature. This paper reports the assessment of RES and/or BTC influence on the photostability of five UV-filters (octyl methoxycinnamate - OMC, avobenzone -AVO, octocrylene - OCT, bemotrizinole - BMZ, octyltriazone - OTZ) in three different combinations after UVA exposure followed by the identification of degradation products and the assessment of photoreactivity. The evaluation of sunscreen photostability was performed by HPLC and spectrophotometric analysis, and degradation products were identified by GC-MS analysis. Components RES, BTC, OMC and AVO were significantly degraded after UV exposure (reduction of around 16% in recovery). According to HPLC analysis, all formulations presented similar photostability profiles. Eleven degradation products were identified in GC-MS analysis, among them products of RES, BTC, OMC and AVO photodegradation. All evaluated formulations were considered photoreactive, as well as the isolated compounds RES and AVO. Considering HPLC, spectrophotometric and GC-MS results, it is suggested that formulations containing BMZ were considered the most photostable. The combination RES+BTC in a sunscreen improved the photostability of AVO. The benefits of using a combination of antioxidants in sunscreens was demonstrated by showing that using RES+BTC+studied UV-filters led to more photostable formulations, which in turn implies in better safety and efficacy. PMID:26159738

  7. Negligible heat strain in armored vehicle officers wearing personal body armor

    PubMed Central

    2011-01-01

    Objectives This study evaluated the heat strain experienced by armored vehicle officers (AVOs) wearing personal body armor (PBA) in a sub-tropical climate. Methods Twelve male AVOs, aged 35-58 years, undertook an eight hour shift while wearing PBA. Heart rate and core temperature were monitored continuously. Urine specific gravity (USG) was measured before and after, and with any urination during the shift. Results Heart rate indicated an intermittent and low-intensity nature of the work. USG revealed six AVOs were dehydrated from pre through post shift, and two others became dehydrated. Core temperature averaged 37.4 ± 0.3°C, with maximum's of 37.7 ± 0.2°C. Conclusions Despite increased age, body mass, and poor hydration practices, and Wet-Bulb Globe Temperatures in excess of 30°C; the intermittent nature and low intensity of the work prevented excessive heat strain from developing. PMID:21801453

  8. 2008 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.; Dixon, James P.; Cameron, Cheryl E.; Nuzhdaev, Anton A.; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest or suspected unrest at seven separate volcanic centers in Alaska during 2008. Significant explosive eruptions at Okmok and Kasatochi Volcanoes in July and August dominated Observatory operations in the summer and autumn. AVO maintained 24-hour staffing at the Anchorage facility from July 12 through August 28. Minor eruptive activity continued at Veniaminof and Cleveland Volcanoes. Observed volcanic unrest at Cook Inlet's Redoubt Volcano presaged a significant eruption in the spring of 2009. AVO staff also participated in hazard communication regarding eruptions or unrest at nine volcanoes in Russia as part of a collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  9. 2012 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Herrick, Julie A.; Neal, Christina A.; Cameron, Cheryl E.; Dixon, James P.; McGimsey, Robert G.

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest, or suspected unrest at 11 volcanic centers in Alaska during 2012. Of the two verified eruptions, one (Cleveland) was clearly magmatic and the other (Kanaga) was most likely a single phreatic explosion. Two other volcanoes had notable seismic swarms that probably were caused by magmatic intrusions (Iliamna and Little Sitkin). For each period of clear volcanic unrest, AVO staff increased monitoring vigilance as needed, reviewed eruptive histories of the volcanoes in question to help evaluate likely outcomes, and shared observations and interpretations with the public. 2012 also was the 100th anniversary of Alaska’s Katmai-Novarupta eruption of 1912, the largest eruption on Earth in the 20th century and one of the most important volcanic eruptions in modern times. AVO marked this occasion with several public events.

  10. Eruption of Alaska volcano breaks historic pattern

    USGS Publications Warehouse

    Larsen, Jessica; Neal, Christina A.; Webley, Peter; Freymueller, Jeff; Haney, Matthew; McNutt, Stephen; Schneider, David; Prejean, Stephanie; Schaefer, Janet; Wessels, Rick L.

    2009-01-01

    In the late morning of 12 July 2008, the Alaska Volcano Observatory (AVO) received an unexpected call from the U.S. Coast Guard, reporting an explosive volcanic eruption in the central Aleutians in the vicinity of Okmok volcano, a relatively young (~2000-year-old) caldera. The Coast Guard had received an emergency call requesting assistance from a family living at a cattle ranch on the flanks of the volcano, who reported loud "thunder," lightning, and noontime darkness due to ashfall. AVO staff immediately confirmed the report by observing a strong eruption signal recorded on the Okmok seismic network and the presence of a large dark ash cloud above Okmok in satellite imagery. Within 5 minutes of the call, AVO declared the volcano at aviation code red, signifying that a highly explosive, ash-rich eruption was under way.

  11. Amplitude versus offset analysis to marine seismic data acquired in Nankai Trough, offshore Japan where methane hydrate exists

    NASA Astrophysics Data System (ADS)

    Hato, M.; Inamori, T.; Matsuoka, T.; Shimizu, S.

    2003-04-01

    Occurrence of methane hydrates in the Nankai Trough, located off the south-eastern coast of Japan, was confirmed by the exploratory test well drilling conducted by Japan’s Ministry of International Trade and Industry in 1999. Confirmation of methane hydrate has given so big impact to the Japan's future energy strategy and scientific and technological interest was derived from the information of the coring and logging results at the well. Following the above results, Japan National Oil Corporation (JNOC) launched the national project, named as MH21, for establishing the technology of methane hydrate exploration and related technologies such as production and development. As one of the research project for evaluating the total amount of the methane hydrate, Amplitude versus Offset (AVO) was applied to the seismic data acquired in the Nankai Trough area. The main purpose of the AVO application is to evaluate the validity of delineation of methane hydrate-bearing zones. Since methane hydrate is thought to accompany with free-gas in general just below the methane hydrate-bearing zones, the AVO has a possibility of describing the presence of free-gas. The free-gas is thought to be located just below the base of methane hydrate stability zone which is characterized by the Bottom Simulating Reflectors (BSRs) on the seismic section. In this sense, AVO technology, which was developed as gas delineation tools, can be utilized for methane hydrate exploration. The result of AVO analysis clearly shows gas-related anomaly below the BSRs. Appearance of the AVO anomaly has so wide variety. Some of the anomalies might not correspond to the free-gas existence, however, some of them may show free-gas. We are now going to develop methodology to clearly discriminate free-gas from non-gas zone by integrating various types of seismic methods such as seismic inversion and seismic attribute analysis.

  12. Use of SAR data to study active volcanoes in Alaska

    USGS Publications Warehouse

    Dean, K.G.; Engle, K.; Lu, Zhiming; Eichelberger, J.; Near, T.; Doukas, M.

    1996-01-01

    Synthetic Aperture Radar (SAR) data of the Westdahl, Veniaminof, and Novarupta volcanoes in the Aleutian Arc of Alaska were analysed to investigate recent surface volcanic processes. These studies support ongoing monitoring and research by the Alaska Volcano Observatory (AVO) in the North Pacific Ocean Region. Landforms and possible crustal deformation before, during, or after eruptions were detected and analysed using data from the European Remote Sensing Satellites (ERS), the Japanese Earth Resources Satellite (JERS) and the US Seasat platforms. Field observations collected by scientists from the AVO were used to verify the results from the analysis of SAR data.

  13. Use of SAR data to study active volcanoes in Alaska

    USGS Publications Warehouse

    Dean, K.G.; Engle, K.; Lu, Zhiming; Eichelberger, J.; Neal, T.; Doukas, M.

    1996-01-01

    Synthetic Aperture Radar (SAR) data of Westdahl, Veniaminof, and Novarupta volcanoes in the Aleutian Arc of Alaska were analyzed to investigate recent surface volcanic processes. These studies support ongoing monitoring and research by the Alaska Volcano Observatory (AVO) in the North Pacific Ocean Region. Landforms and possible crustal deformation before, during, or after eruptions were detected and analyzed using data from the European Remote Sensing Satellites (ERS), Japanese Earth Resources Satellite (JERS) and the U. S. Seasat platforms. Field observations collected by scientists from the AVO were used to verify the results from the analysis of SAR data.

  14. 2009 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Girina, Olga A.; Chibisova, Marina; Rybin, Alexander

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest, and reports of unusual activity at or near eight separate volcanic centers in Alaska during 2009. The year was highlighted by the eruption of Redoubt Volcano, one of three active volcanoes on the western side of Cook Inlet and near south-central Alaska's population and commerce centers, which comprise about 62 percent of the State's population of 710,213 (2010 census). AVO staff also participated in hazard communication and monitoring of multiple eruptions at ten volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  15. Amplitude versus offset modeling of the bottom simulating reflection associated with submarine gas hydrates

    USGS Publications Warehouse

    Andreassen, K.; Hart, P.E.; MacKay, M.

    1997-01-01

    A bottom simulating seismic reflection (BSR) that parallels the sea floor occurs worldwide on seismic profiles from outer continental margins. The BSR coincides with the base of the gas hydrate stability field and is commonly used as indicator of natural submarine gas hydrates. Despite the widespread assumption that the BSR marks the base of gas hydrate-bearing sediments, the occurrence and importance of low-velocity free gas in the sediments beneath the BSR has long been a subject of debate. This paper investigates the relative abundance of hydrate and free gas associated with the BSR by modeling the reflection coefficient or amplitude variation with offset (AVO) of the BSR at two separate sites, offshore Oregon and the Beaufort Sea. The models are based on multichannel seismic profiles, seismic velocity data from both sites and downhole log data from Oregon ODP Site 892. AVO studies of the BSR can determine whether free gas exists beneath the BSR if the saturation of gas hydrate above the BSR is less than approximately 30% of the pore volume. Gas hydrate saturation above the BSR can be roughly estimated from AVO studies, but the saturation of free gas beneath the BSR cannot be constrained from the seismic data alone. The AVO analyses at the two study locations indicate that the high amplitude BSR results primarily from free gas beneath the BSR. Hydrate concentrations above the BSR are calculated to be less than 10% of the pore volume for both locations studied.

  16. 78 FR 16864 - Agency Information Collection Activities: Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-19

    ... control number. Comments: On June 11, 2012, we published a Federal Register Notice (77 FR 34400... to correct or refine ash fall forecasts as the ash cloud moves downwind. Retrospectively these... report database will help AVO track eruption clouds and associated fallout downwind. These reports...

  17. New technology for the independent producer

    SciTech Connect

    Not Available

    1993-07-01

    This technology transfer conference consisted of the following six sessions: reservoir characterization; drilling, testing and completion; enhanced oil recovery; 3-d seismic and amplitude variation with offset (AVO); biotechnology for field applications; and well logging technology. Selected papers have been processed separately for inclusion in the Energy Science and Technology Database.

  18. Emergy analysis of a silvo-pastoral system, a case study in southern Portugal

    EPA Science Inventory

    The Mediterranean silvo-pastoral system known as Montado, in Portugal, is a complex land use system composed of an open tree stratum in various densities and an herbaceous layer, used for livestock grazing. Livestock also profit from the acorns, and the grazing contributes to avo...

  19. 2005 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, R.G.; Neal, C.A.; Dixon, J.P.; Ushakov, Sergey

    2008-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity at or near 16 volcanoes in Alaska during 2005, including the high profile precursory activity associated with the 2005?06 eruption of Augustine Volcano. AVO continues to participate in distributing information about eruptive activity on the Kamchatka Peninsula, Russia, and in the Kurile Islands of the Russian Far East, in conjunction with the Kamchatkan Volcanic Eruption Response Team (KVERT) and the Sakhalin Volcanic Eruption Response Team (SVERT), respectively. In 2005, AVO helped broadcast alerts about activity at 8 Russian volcanoes. The most serious hazard posed from volcanic eruptions in Alaska, Kamchatka, or the Kurile Islands is the placement of ash into the atmosphere at altitudes traversed by jet aircraft along the North Pacific and Russian Trans East air routes. AVO, KVERT, and SVERT work collaboratively with the National Weather Service, Federal Aviation Administration, and the Volcanic Ash Advisory Centers to provide timely warnings of volcanic eruptions and the production and movement of ash clouds.

  20. Use of new and old technologies and methods by the Alaska Volcano Observatory during the 2006 eruption of Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Murray, T. L.; Nye, C. J.; Eichelberger, J. C.

    2006-12-01

    The recent eruption of Augustine Volcano was the first significant volcanic event in Cook Inlet, Alaska since 1992. In contrast to eruptions at remote Alaskan volcanoes that mainly affect aviation, ash from previous eruptions of Augustine has affected communities surrounding Cook Inlet, home to over half of Alaska's population. The 2006 eruption validated much of AVO's advance preparation, underscored the need to quickly react when a problem or opportunity developed, and once again demonstrated that while technology provides us with wonderful tools, professional relationships, especially during times of crisis, are still important. Long-term multi-parametric instrumental monitoring and background geological and geophysical studies represent the most fundamental aspect of preparing for any eruption. Once significant unrest was detected, AVO augmented the existing real-time network with additional instrumentation including web cameras. GPS and broadband seismometers that recorded data on site were also quickly installed as their data would be crucial for post-eruption research. Prior to 2006, most of most of AVO's eruption response plans and protocols had focused on the threat to aviation rather than ground-based hazards. However, the relationships and protocols developed for the aviation threat were sufficient to be adapted to the ash fall hazard, though it is apparent that more work, both scientific and with response procedures, is needed. Similarly, protocols were quickly developed for warning of a flank- collapse induced tsunami. Information flow within the observatory was greatly facilitated by an internal web site that had been developed and refined specifically for eruption response. Because AVO is a partnership of 3 agencies (U.S. Geological Survey, University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys) with offices in both Fairbanks and Anchorage, web and internet-facing data servers provided

  1. Hazard communication by the Alaska Volcano Observatory Concerning the 2008 Eruptions of Okmok and Kasatochi Volcanoes, Aleutian Islands, Alaska

    NASA Astrophysics Data System (ADS)

    Adleman, J. N.; Cameron, C. E.; Neal, T. A.; Shipman, J. S.

    2008-12-01

    The significant explosive eruptions of Okmok and Kasatochi volcanoes in 2008 tested the hazard communication systems at the Alaska Volcano Observatory (AVO) including a rigorous test of the new format for written notices of volcanic activity. AVO's Anchorage-based Operations facility (Ops) at the USGS Alaska Science Center serves as the hub of AVO's eruption response. From July 12 through August 28, 2008 Ops was staffed around the clock (24/7). Among other duties, Ops staff engaged in communicating with the public, media, and other responding federal and state agencies and issued Volcanic Activity Notices (VAN) and Volcano Observatory Notifications for Aviation (VONA), recently established and standardized products to announce eruptions, significant activity, and alert level and color code changes. In addition to routine phone communications with local, national and international media, on July 22, AVO held a local press conference in Ops to share observations and distribute video footage collected by AVO staff on board a U.S. Coast Guard flight over Okmok. On July 27, AVO staff gave a public presentation on the Okmok eruption in Unalaska, AK, 65 miles northeast of Okmok volcano and also spoke with local public safety and industry officials, observers and volunteer ash collectors. AVO's activity statements, photographs, and selected data streams were posted in near real time on the AVO public website. Over the six-week 24/7 period, AVO staff logged and answered approximately 300 phone calls in Ops and approximately 120 emails to the webmaster. Roughly half the logged calls were received from interagency cooperators including NOAA National Weather Service's Alaska Aviation Weather Unit and the Center Weather Service Unit, both in Anchorage. A significant number of the public contacts were from mariners reporting near real-time observations and photos of both eruptions, as well as the eruption of nearby Cleveland Volcano on July 21. As during the 2006 eruption of

  2. Monitoring and analyses of volcanic activity using remote sensing data at the Alaska Volcano Observatory: Case study for Kamchatka, Russia, December 1997

    NASA Astrophysics Data System (ADS)

    Schneider, D. J.; Dean, K., G.; Dehn, J.; Miller, T., P.; Kirianov, V. Yu.

    There are about 100 potentially active volcanoes in the North Pacific Ocean region that includes Alaska, the Kamchatka Peninsula, and the Kurile Islands, but fewer than 25% are monitored seismically. The region averages about five volcanic eruptions per year, and more than 20,000 passengers and millions of dollars of cargo fly the air routes in this region each day. One of the primary public safety objectives of the Alaska Volcano Observatory (AVO) is to mitigate the hazard posed by volcanic ash clouds drifting into these busy air traffic routes. The AVO uses real-time remote sensing data (AVHRR, GOES, and GMS) in conjunction with other methods (primarily seismic) to monitor and analyze volcanic activity in the region. Remote sensing data can be used to detect volcanic thermal anomalies and to provide unique information on the location, movement, and composition of volcanic eruption clouds. Satellite images are routinely analyzed twice each day at AVO and many times per day during crisis situations. As part of its formal working relationship with the Kamchatka Volcanic Eruption Response Team (KVERT), the AVO provides satellite observations of volcanic activity in Kamchatka and distributes notices of volcanic eruptions from KVERT to non-Russian users in the international aviation community. This paper outlines the current remote sensing capabilities and operations of the AVO and describes the responsibilities and procedures of federal agencies and international aviation organizations for volcanic eruptions in the North Pacific region. A case study of the December 4, 1997, eruption of Bezymianny volcano, Russia, is used to illustrate how real-time remote sensing and hazard communication are used to mitigate the threat of volcanic ash to aircraft.

  3. Absolute silicon molar mass measurements, the Avogadro constant and the redefinition of the kilogram

    NASA Astrophysics Data System (ADS)

    Vocke, R. D., Jr.; Rabb, S. A.; Turk, G. C.

    2014-10-01

    The results of an absolute silicon molar mass determination of two independent sets of samples from the highly 28Si-enriched crystal (AVO28) produced by the International Avogadro Coordination are presented and compared with results published by the Physikalisch-Technische Bundesanstalt (PTB, Germany), the National Research Council (NRC, Canada) and the National Metrology Institute of Japan (NMIJ, Japan). This study developed and describes significant changes to the published protocols for producing absolute silicon isotope ratios. The measurements were made at very high resolution on a multi-collector inductively coupled plasma mass spectrometer using tetramethylammonium hydroxide (TMAH) to dissolve and dilute all samples. The various changes in the measurement protocol and the use of TMAH resulted in significant improvements to the silicon isotope ratio precision over previously reported measurements and in particular, the robustness of the 29Si/30Si ratio of the AVO28 material. These new results suggest that a limited isotopic variability is present in the AVO28 material. The presence of this variability is at present singular and therefore its significance is not well understood. Fortunately, its magnitude is small enough so as to have an insignificant effect on the overall uncertainty of an Avogadro constant derived from the average molar mass of all four AVO28 silicon samples measured in this study. The NIST results confirm the AVO28 molar mass values reported by PTB and NMIJ and confirm that the virtual element-isotope dilution mass spectrometry approach to calibrated absolute isotope ratio measurements developed by PTB is capable of very high precision as well as accuracy. The Avogadro constant NA and derived Planck constant h based on these measurements, together with their associated standard uncertainties, are 6.02214076(19) × 1023 mol-1 and 6.62607017(21) × 10-34 Js, respectively.

  4. Effect of dose and frequency of interferon beta-1a administration on clinical and magnetic resonance imaging parameters in relapsing-remitting multiple sclerosis.

    PubMed

    Cocco, Eleonora; Marchi, Piernicola; Floris, Gianluca; Mascia, Maria Giuseppina; Deriu, Marcello; Sirca, Antonella; Mamusa, Elena; Lai, Marina; Mura, Marco; Mallarini, Giorgio; Marrosu, Maria Giovanna

    2006-01-01

    There is still debate over the optimal dosage, frequency and route of administration of interferon (IFN) beta in multiple sclerosis (MS). A prospective, non-randomized, comparative study was performed to evaluate differences in magnetic resonance imaging and clinical outcomes of two IFN beta-1a preparations (30mcg intramuscular [im] once-weekly [qw], AVO; and 22 mcg subcutaneous [sc] three-times-weekly [tiw]; R22). Relapsing-remitting MS patients on one of the two IFN preparations (AVO, n=47; R22, n=48) were assessed at baseline and after 6 months of further treatment. There were no significant differences between the two groups at baseline. Both groups showed significantly reduced relapse rates (F=19.5; p<0.001) from baseline (0.6) to 6-month assessment (0.2; p<0.001). Univariate analysis showed a significant difference in favour of R22 on T2 lesion volume (F=14.4; p<0.001) and T1 black hole lesion load (F=8.5; p=0.004), the latter showing a significant increase in the AVO group (p<0.001). The incidence of patients with new T1 black holes was also higher for AVO than R22 (23.5% vs 8.3%; p=0.025). These results from patients receiving AVO or R22 in normal clinical practice are in line with randomized clinical studies that show the benefits of high-dose, high-frequency administration of IFN beta-1a in MS therapy. PMID:17049133

  5. Catalog of Earthquake Hypocenters at Alaskan Volcanoes: January 1 through December 31, 2008

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.

    2009-01-01

    Between January 1 and December 31, 2008, the Alaska Volcano Observatory (AVO) located 7,097 earthquakes of which 5,318 occurred within 20 kilometers of the 33 volcanoes monitored by the AVO. Monitoring highlights in 2008 include the eruptions of Okmok Caldera, and Kasatochi Volcano, as well as increased unrest at Mount Veniaminof and Redoubt Volcano. This catalog includes descriptions of: (1) locations of seismic instrumentation deployed during 2008; (2) earthquake detection, recording, analysis, and data archival systems; (3) seismic velocity models used for earthquake locations; (4) a summary of earthquakes located in 2008; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, phase arrival times, location quality statistics, daily station usage statistics, and all files used to determine the earthquake locations in 2008.

  6. Intraventricular vorticity favors conservation of kinetic energy along the cardiac cycle: analysis in patients with dilated cardiomyopathy by post-processing color-doppler images

    NASA Astrophysics Data System (ADS)

    Alhama, Marta; Benito, Yolanda; Bermejo, Javier; Yotti, Raquel; Perez-David, Esther; Barrio, Alicia; Perez Del Villar, Candelas; Gonzalez Mansilla, Ana; Fernandez Aviles, Francisco; Del Alamo, Juan Carlos

    2011-11-01

    Background: This study assesses if the left ventricle (LV) filling vortex developed during diastole may be a mechanism that improves systolic efficiency. 19 patients with dilated cardiomyopathy (DCM) and 37 healthy volunteers were studied. Recently, we have developed and validated a method that derives two-dimensional maps of the LV flow from standard color-Doppler sequences. Two-dimensional maps of instantaneous LV flow were obtained, and circulation, energy and position of the main and secondary vortices were calculated along the cardiac cycle. At aortic valve opening (AVO) the vortex circulation is higher in DCM subjects than healthy volunteers. However, the position of the vortex is farthest form LV outflow tract (LVOT), and this results in lower flow velocity in LVOT at AVO. This phenomenon is altered in patients with DCM. Supported by ISCIII (Spain) and NIH 1 R21 HL108268-01 (US).

  7. A description of seismic amplitude techniques

    NASA Astrophysics Data System (ADS)

    Shadlow, James

    2014-02-01

    The acquisition of seismic data is a non-invasive technique used for determining the sub surface geology. Changes in lithology and fluid fill affect the seismic wavelet. Analysing seismic data for direct hydrocarbon indicators (DHIs), such as full stack amplitude anomalies, or amplitude variation with offset (AVO), can help a seismic interpreter relate the geophysical response to real geology and, more importantly, to distinguish the presence of hydrocarbons. Inversion is another commonly used technique that attempts to tie the seismic data back to the geology. Much has been written about these techniques, and attempting to gain an understanding on the theory and application of them by reading through various journals can be quite daunting. The purpose of this paper is to briefly outline DHI analysis, including full stack amplitude anomalies, AVO and inversion and show the relationship between all three. The equations presented have been included for completeness, but the reader can pass over the mathematical detail.

  8. 2007 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Dixon, James P.; Malik, Nataliya; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near nine separate volcanic centers in Alaska during 2007. The year was highlighted by the eruption of Pavlof, one of Alaska's most frequently active volcanoes. Glaciated Fourpeaked Mountain, a volcano thought to have been inactive in the Holocene, produced a phreatic eruption in the autumn of 2006 and continued to emit copious amounts of steam and volcanic gas into 2007. Redoubt Volcano showed the first signs of the unrest that would unfold in 2008-09. AVO staff also participated in hazard communication and monitoring of multiple eruptions at seven volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  9. 2006 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.; Dixon, James P.; Manevich, Alexander; Rybin, Alexander

    2008-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near nine separate volcanic centers in Alaska during 2006. A significant explosive eruption at Augustine Volcano in Cook Inlet marked the first eruption within several hundred kilometers of principal population centers in Alaska since 1992. Glaciated Fourpeaked Mountain, a volcano thought to have been inactive in the Holocene, produced a phreatic eruption in the fall of 2006 and continued to emit copious amounts of volcanic gas into 2007. AVO staff also participated in hazard communication and monitoring of multiple eruptions at seven volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  10. Implementation of Simple and Functional Web Applications at the Alaska Volcano Observatory Remote Sensing Group

    NASA Astrophysics Data System (ADS)

    Skoog, R. A.

    2007-12-01

    Web pages are ubiquitous and accessible, but when compared to stand-alone applications they are limited in capability. The Alaska Volcano Observatory (AVO) Remote Sensing Group has implemented web pages and supporting server software that provide relatively advanced features to any user able to meet basic requirements. Anyone in the world with access to a modern web browser (such as Mozilla Firefox 1.5 or Internet Explorer 6) and reasonable internet connection can fully use the tools, with no software installation or configuration. This allows faculty, staff and students at AVO to perform many aspects of volcano monitoring from home or the road as easily as from the office. Additionally, AVO collaborators such as the National Weather Service and the Anchorage Volcanic Ash Advisory Center are able to use these web tools to quickly assess volcanic events. Capabilities of this web software include (1) ability to obtain accurate measured remote sensing data values on an semi- quantitative compressed image of a large area, (2) to view any data from a wide time range of data swaths, (3) to view many different satellite remote sensing spectral bands and combinations, to adjust color range thresholds, (4) and to export to KML files which are viewable virtual globes such as Google Earth. The technologies behind this implementation are primarily Javascript, PHP, and MySQL which are free to use and well documented, in addition to Terascan, a commercial software package used to extract data from level-0 data files. These technologies will be presented in conjunction with the techniques used to combine them into the final product used by AVO and its collaborators for operational volcanic monitoring.

  11. Mangiferin and naringenin affect the photostability and phototoxicity of sunscreens containing avobenzone.

    PubMed

    Kawakami, Camila Martins; Gaspar, Lorena Rigo

    2015-10-01

    Efficient UV-absorbing molecules are designed to protect against UV-light exposure. However, the development of photostable sunscreens is important to preserve the photoprotective efficacy and to prevent the formation of reactive oxygen species (ROS) and photodegradation products, which can promote phototoxic or photoallergic contact dermatitis. The aim of this study was to evaluate the effects of mangiferin and naringenin on the photostability and phototoxicity of sunscreens containing avobenzone. Cosmetic sunscreen formulations containing octocrylene (OCT), octyl methoxycinnamate (OMC) and avobenzone (AVO) were prepared and supplemented or not with mangiferin, naringenin, or with both compounds in combination. For photostability studies, samples of the formulations were spread onto glass plates, exposed to UVA radiation and then analyzed by high performance liquid chromatography (HPLC) to determine UV filters and the antioxidants recovery. The phototoxicity of the UV filters and antioxidants was evaluated using 3T3 fibroblast cultures that were subjected (or not) to irradiation according to OECD TG 432. The photostability studies demonstrated that AVO and naringenin showed the highest photodegradation when present in formulation FN (containing octocrylene, avobenzone, octyl methoxycinnamate and naringenin). The addition of mangiferin to this combination (FMN) resulted in an improved photostability of both substances compared to FN. The in vitro phototoxicity test showed that only avobenzone was considered phototoxic. The combination containing AVO/naringenin exhibited phototoxic potential; however, this was reduced by the addition of mangiferin (combination CMN). The results of this study are promising because it was demonstrated that mangiferin could increase the photostability and reduce the phototoxic potential of the combination of naringenin and AVO. PMID:26318281

  12. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2011

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Searcy, Cheryl K.

    2012-01-01

    Between January 1 and December 31, 2011, the Alaska Volcano Observatory (AVO) located 4,364 earthquakes, of which 3,651 occurred within 20 kilometers of the 33 volcanoes with seismograph subnetworks. There was no significant seismic activity above background levels in 2011 at these instrumented volcanic centers. This catalog includes locations, magnitudes, and statistics of the earthquakes located in 2011 with the station parameters, velocity models, and other files used to locate these earthquakes.

  13. Seismic offset balancing

    SciTech Connect

    Ross, C.P.; Beale, P.L.

    1994-01-01

    The ability to successfully predict lithology and fluid content from reflection seismic records using AVO techniques is contingent upon accurate pre-analysis conditioning of the seismic data. However, all too often, residual amplitude effects remain after the many offset-dependent processing steps are completed. Residual amplitude effects often represent a significant error when compared to the amplitude variation with offset (AVO) response that the authors are attempting to quantify. They propose a model-based, offset-dependent amplitude balancing method that attempts to correct for these residuals and other errors due to sub-optimal processing. Seismic offset balancing attempts to quantify the relationship between the offset response of back-ground seismic reflections and corresponding theoretical predictions for average lithologic interfaces thought to cause these background reflections. It is assumed that any deviation from the theoretical response is a result of residual processing phenomenon and/or suboptimal processing, and a simple offset-dependent scaling function is designed to correct for these differences. This function can then be applied to seismic data over both prospective and nonprospective zones within an area where the theoretical values are appropriate and the seismic characteristics are consistent. A conservative application of the above procedure results in an AVO response over both gas sands and wet sands that is much closer to theoretically expected values. A case history from the Gulf of Mexico Flexure Trend is presented as an example to demonstrate the offset balancing technique.

  14. Solid State Structure-Reactivity Studies on Bixbyites, Fluorites and Perovskites Belonging to the Vanadate, Titanate and Cerate Families

    NASA Astrophysics Data System (ADS)

    Shafi, Shahid P.

    This thesis primarily focuses on the systematic understanding of structure-reactivity relationships in two representative systems: bixbyite and related structures as well as indium doped CeO2. Topotactic reaction routes have gained significant attention over the past two decades due to their potential to access kinetically controlled metastable materials. This has contributed substantially to the understanding of solid state reaction pathways and provided first insights into mechanisms. Contrary to the widely used ex-situ methods, in-situ techniques including powder x-ray diffraction and thermogravimetric-differential thermal analysis have been employed extensively throughout this work in order to follow the reaction pathways in real time. Detailed analysis of the AVO3 (A = In, Sc) bixbyite reactivity under oxidative conditions has been carried out and a variety of novel metastable oxygen defect phases have been identified and characterized. The novel metastable materials have oxygen deficient fluorite structures and consequently are potential ion conductors. Structural aspects of the topotactic vs. reconstructive transformations are illustrated with this model system. The structure-reactivity study of AVO3 phases was extended to AVO3 perovskite family. Based on the research methodologies and results from AVO3 bixbyite reactivity studies a generalized mechanistic oxidation pathway has been established with a non-vanadium phase, ScTiO3 bixbyite. However, there is stark contrast in terms of structural stability and features beyond this stability limit during AVO3 and ScTiO3 bixbyite reaction pathways. A series of complex reaction sequences including phase separation and phase transitions were identified during the investigation of ScTiO3 reactivity. The two-step formation pathway for the fluorite-type oxide ion conductor Ce1-xInxO2-delta (0 ≤ x ≤ 0.3) is being reported. The formation of the BaCe1-xInxO 3-delta perovskites and the subsequent CO2-capture reaction

  15. High-Resolution Fault Zone Monitoring and Imaging Using Long Borehole Arrays

    NASA Astrophysics Data System (ADS)

    Paulsson, B. N.; Karrenbach, M.; Goertz, A. V.; Milligan, P.

    2004-12-01

    Long borehole seismic receiver arrays are increasingly used in the petroleum industry as a tool for high--resolution seismic reservoir characterization. Placing receivers in a borehole avoids the distortion of reflected seismic waves by the near-surface weathering layer which leads to greatly improved vector fidelity and a much higher frequency content of 3-component recordings. In addition, a borehole offers a favorable geometry to image near-vertically dipping or overturned structure such as, e.g., salt flanks or faults. When used for passive seismic monitoring, long borehole receiver arrays help reducing depth uncertainties of event locations. We investigate the use of long borehole seismic arrays for high-resolution fault zone characterization in the vicinity of the San Andreas Fault Observatory at Depth (SAFOD). We present modeling scenarios to show how an image of the vertically dipping fault zone down to the penetration point of the SAFOD well can be obtained by recording surface sources in a long array within the deviated main hole. We assess the ability to invert fault zone reflections for rock physical parameters by means of amplitude versus offset or angle (AVO/AVA) analyzes. The quality of AVO/AVA studies depends on the ability to illuminate the fault zone over a wide range of incidence angles. We show how the length of the receiver array and the receiver spacing within the borehole influence the size of the volume over which reliable AVO/AVA information could be obtained. By means of AVO/AVA studies one can deduce hydraulic properties of the fault zone such as the type of fluids that might be present, the porosity, and the fluid saturation. Images of the fault zone obtained from a favorable geometry with a sufficient illumination will enable us to map fault zone properties in the surrounding of the main hole penetration point. One of the targets of SAFOD is to drill into an active rupture patch of an earthquake cluster. The question of whether or not

  16. Amplitude vs. Offset Effects on Gas Hydrates at Woolsey Mound, Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Anderson, Walter R., Jr.

    Due to the estimated massive quantities of natural methane hydrates, they represent one of the largest sources of future alternative energy on Earth. Methane hydrates have been found in the shallow sub-seafloor of the Northern Gulf of Mexico where the water depth is in excess of ~900 m. Mississippi Canyon Block 118 has been chosen by the Gulf of Mexico Hydrates Research Consortium to be the site of a multi-sensor, multi-discipline sea-floor observatory for gas hydrate research. First evidence for gas hydrates at MC 118 was observed at Woolsey Mound. Subsurface evidence for gas hydrates has subsequently been substantiated by 3D seismic reflection data and piston coring. It is estimated that methane trapped within gas hydrates worldwide may exceed 1016 kg, one of the largest sources of hydrocarbons to date, and here they present an opportunity for exploitation via harvesting for energy production. The analysis of the 3-D seismic reflection data and integration with industry well logs reveals the subsurface structural and stratigraphic architecture of a thermogenic hydrate system in the Mississippi Canyon area (MC-118) of the Gulf of Mexico. Like many hydrocarbon systems in the Gulf of Mexico, Woolsey Mound is dominated by the presence and sporadic movement of allochthonous salt within the sedimentary section. Exploration-scale 3-D seismic imaging shows a network of faults connecting the mound to a salt diapir and an extended area of high P-wave velocity just beneath the sea floor. Gas hydrates exhibit clear seismic properties such as the bottom simulating reflector (BSR), relatively high P- and S- wave velocities, seismic blanking, and amplitude vs. offset (AVO) effects. These effects occur mainly due to the presence of free gas that is usually trapped by the more rigid overlying hydrate formations. In order to substantiate the presence of hydrates in the shallow subsurface at Woolsey Mound, an AVO analysis based on the variation of the P-wave reflection coefficient

  17. Exploring the Digital Universe with Europe's Astrophysical Virtual Observatory

    NASA Astrophysics Data System (ADS)

    2001-12-01

    Vast Databanks at the Astronomers' Fingertips Summary A new European initiative called the Astrophysical Virtual Observatory (AVO) is being launched to provide astronomers with a breathtaking potential for new discoveries. It will enable them to seamlessly combine the data from both ground- and space-based telescopes which are making observations of the Universe across the whole range of wavelengths - from high-energy gamma rays through the ultraviolet and visible to the infrared and radio. The aim of the Astrophysical Virtual Observatory (AVO) project, which started on 15 November 2001, is to allow astronomers instant access to the vast databanks now being built up by the world's observatories and which are forming what is, in effect, a "digital sky" . Using the AVO, astronomers will, for example, be able to retrieve the elusive traces of the passage of an asteroid as it passes near the Earth and so enable them to predict its future path and perhaps warn of a possible impact. When a giant star comes to the end of its life in a cataclysmic explosion called a supernova, they will be able to access the digital sky and pinpoint the star shortly before it exploded so adding invaluable data to the study of the evolution of stars. Background information on the Astrophysical Virtual Observatory is available in the Appendix. PR Photo 34a/01 : The Astrophysical Virtual Observatory - an artist's impression. The rapidly accumulating database ESO PR Photo 34a/01 ESO PR Photo 34a/01 [Preview - JPEG: 400 x 345 pix - 90k] [Normal - JPEG: 800 x 689 pix - 656k] [Hi-Res - JPEG: 3000 x 2582 pix - 4.3M] ESO PR Photo 34a/01 shows an artist's impression of the Astrophysical Virtual Observatory . Modern observatories observe the sky continuously and data accumulates remorselessly in the digital archives. The growth rate is impressive and many hundreds of terabytes of data - corresponding to many thousands of billions of pixels - are already available to scientists. The real sky is being

  18. Exploring the Digital Universe with Europe's Astrophysical Virtual Observatory

    NASA Astrophysics Data System (ADS)

    2001-12-01

    N° 73-2001 - Paris, 5 December 2001 The aim of AVO is to give astronomers instant access to the vast databanks now being built up by the world's observatories and forming what is in effect a "digital sky". Using AVO astronomers will be able, for example, to retrieve the elusive traces of the passage of an asteroid as it passes the Earth and so predict its future path and perhaps warn of a possible impact. When a giant star comes to the end of its life in a cataclysmic explosion called a supernova, they will be able to access the digital sky and pinpoint the star shortly before it exploded, adding invaluable data to the study of the evolution of stars. Modern observatories observe the sky continuously and data accumulates remorselessly in the digital archives. The growth rate is impressive and many hundreds of terabytes of data -corresponding to many thousands of billions of pixels - are already available to scientists. The real sky is being digitally reconstructed in the databanks. The volume and complexity of data and information available to astronomers are overwhelming. Hence the problem of how astronomers can possibly manage, distribute and analyse this great wealth of data. The Astrophysical Virtual Observatory will enable them to meet the challenge and "put the Universe online". AVO is a three-year project, funded by the European Commission under its Research and Technological Development (RTD) scheme, to design and implement a virtual observatory for the European astronomical community. The Commission has awarded a contract valued at EUR 4m for the project, starting on 15 November. AVO will provide software tools to enable astronomers to access the multi-wavelength data archives over the Internet and so give them the capability to resolve fundamental questions about the Universe by probing the digital sky. Equivalent searches of the "real" sky would, in comparison, both be prohibitively costly and take far too long. Towards a Global Virtual Observatory The

  19. Alaska Volcano Observatory at 20

    NASA Astrophysics Data System (ADS)

    Eichelberger, J. C.

    2008-12-01

    The Alaska Volcano Observatory (AVO) was established in 1988 in the wake of the 1986 Augustine eruption through a congressional earmark. Even within the volcanological community, there was skepticism about AVO. Populations directly at risk in Alaska were small compared to Cascadia, and the logistical costs of installing and maintaining monitoring equipment were much higher. Questions were raised concerning the technical feasibility of keeping seismic stations operating through the long, dark, stormy Alaska winters. Some argued that AVO should simply cover Augustine with instruments and wait for the next eruption there, expected in the mid 90s (but delayed until 2006), rather than stretching to instrument as many volcanoes as possible. No sooner was AVO in place than Redoubt erupted and a fully loaded passenger 747 strayed into the eruption cloud between Anchorage and Fairbanks, causing a powerless glide to within a minute of impact before the pilot could restart two engines and limp into Anchorage. This event forcefully made the case that volcano hazard mitigation is not just about people and infrastructure on the ground, and is particularly important in the heavily traveled North Pacific where options for flight diversion are few. In 1996, new funding became available through an FAA earmark to aggressively extend volcano monitoring far into the Aleutian Islands with both ground-based networks and round-the-clock satellite monitoring. Beyond the Aleutians, AVO developed a monitoring partnership with Russians volcanologists at the Institute of Volcanology and Seismology in Petropavlovsk-Kamchatsky. The need to work together internationally on subduction phenomena that span borders led to formation of the Japan-Kamchatka-Alaska Subduction Processes (JKASP) consortium. JKASP meets approximately biennially in Sapporo, Petropavlovsk, and Fairbanks. In turn, these meetings and support from NSF and the Russian Academy of Sciences led to new international education and

  20. Further insights in the ability of classical nonadditive potentials to model actinide ion-water interactions.

    PubMed

    Réal, Florent; Trumm, Michael; Schimmelpfennig, Bernd; Masella, Michel; Vallet, Valérie

    2013-04-01

    Pursuing our efforts on the development of accurate classical models to simulate radionuclides in complex environments (Réal et al., J. Phys. Chem. A 2010, 114, 15913; Trumm et al. J. Chem. Phys. 2012, 136, 044509), this article places a large emphasis on the discussion of the influence of models/parameters uncertainties on the computed structural, dynamical, and temporal properties. Two actinide test cases, trivalent curium and tetravalent thorium, have been studied with three different potential energy functions, which allow us to account for the polarization and charge-transfer effects occurring in hydrated actinide ion systems. The first type of models considers only an additive energy term for modeling ion/water charge-transfer effects, whereas the other two treat cooperative charge-transfer interactions with two different analytical expressions. Model parameters are assigned to reproduce high-level ab initio data concerning only hydrated ion species in gas phase. For the two types of cooperative charge-transfer models, we define two sets of parameters allowing or not to cancel out possible errors inherent to the force field used to model water/water interactions at the ion vicinity. We define thus five different models to characterize the solvation of each ion. For both ions, our cooperative charge-transfer models lead to close results in terms of structure in solution: the coordination number is included within 8 and 9, and the mean ion/water oxygen distances are 2.45 and 2.49 Å, respectively, for Th(IV) and Cm(III). PMID:23233426

  1. NON-INVASIVE DETERMINATION OF THE LOCATION AND DISTRIBUTION OF FREE-PHASE DENSE NONAQUEOUS PHASE LIQUIDS (DNAPL) BY SEISMIC REFLECTION TECHNIQUES

    SciTech Connect

    Michael G. Waddell; William J. Domoracki; Tom J. Temples

    2001-12-01

    This annual technical progress report is for part of Task 4 (site evaluation), Task 5 (2D seismic design, acquisition, and processing), and Task 6 (2D seismic reflection, interpretation, and AVO analysis) on DOE contact number DE-AR26-98FT40369. The project had planned one additional deployment to another site other than Savannah River Site (SRS) or DOE Hanford Site. After the SUBCON midyear review in Albuquerque, NM, it was decided that two additional deployments would be performed. The first deployment is to test the feasibility of using non-invasive seismic reflection and AVO analysis as a monitoring tool to assist in determining the effectiveness of Dynamic Underground Stripping (DUS) in removal of DNAPL. The second deployment is to the Department of Defense (DOD) Charleston Naval Weapons Station Solid Waste Management Unit 12 (SWMU-12), Charleston, SC to further test the technique to detect high concentrations of DNAPL. The Charleston Naval Weapons Station SWMU-12 site was selected in consultation with National Energy Technology Laboratory (NETL) and DOD Naval Facilities Engineering Command Southern Division (NAVFAC) personnel. Based upon the review of existing data and due to the shallow target depth, the project team collected three Vertical Seismic Profiles (VSP) and an experimental P-wave seismic reflection line. After preliminary data analysis of the VSP data and the experimental reflection line data, it was decided to proceed with Task 5 and Task 6. Three high resolution P-wave reflection profiles were collected with two objectives; (1) design the reflection survey to image a target depth of 20 feet below land surface to assist in determining the geologic controls on the DNAPL plume geometry, and (2) apply AVO analysis to the seismic data to locate the zone of high concentration of DNAPL. Based upon the results of the data processing and interpretation of the seismic data, the project team was able to map the channel that is controlling the DNAPL plume

  2. Relationship of P-wave seismic attributes, azimuthal anisotropy, and commercial gas pay in 3-D P-wave multiazimuth data, Rulison field, Piceance Basin, Colorado

    SciTech Connect

    Lynn, H.B.; Campagna, D.; Simon, K.M.; Beckham, W.E.

    1999-08-01

    This case history is one of three field projects funded by the US Department of Energy a part of its ongoing research effort aimed to expand current levels of drilling and production efficiency in naturally-fractured tight-gas reservoirs. The original states goal for the 3-D P-wave seismic survey was to evaluate and map fracture azimuth and relative fracture density throughout a naturally-fractured gas reservoir interval. At Rulison field, this interval is the Cretaceous Mesaverde, approximately 2,500 ft (760 m) of lenticular sands, silts, and shales. Three-dimensional full-azimuth P-wave data were acquired for the evaluation of azimuthal anisotropy and the relationship of the anisotropy to commercial pay in the target interval. The methodology is based on the evaluation of two restricted-azimuth orthogonal (source receiver azimuth) 3-D P-wave volumes aligned with the natural principal axes of the azimuthal anisotropy, as estimated from velocity analysis of multiazimuth prestack gathers. The Dix interval velocity, as well as the interval amplitude variation with offset (AVO) gradient, was calculated for both azimuths for the gas-saturated Mesaverde interval. The two seismic attributes best correlated with commercial gas pay (at a 21-well control set) were (1) values greater than 4% azimuthal variation in the interval velocity ratio (source-receiver azimuth N60E/N30W) of the target interval (the gas-saturated Mesaverde), and (2) the sum of the interval AVO gradients (N60E + N30W). The sum of the interval AVO gradients is an attribute sensitive to the presence of gas, but not diagnostic of an azimuthal variation in the amplitude. The two-azimuth interval velocity anisotropy mapped over the survey area suggests spatial variations in the orientation of the maximum horizontal stress field and the open (to flow) fracture system.

  3. Advancing New 3D Seismic Interpretation Methods for Exploration and Development of Fractured Tight Gas Reservoirs

    SciTech Connect

    James Reeves

    2005-01-31

    In a study funded by the U.S. Department of Energy and GeoSpectrum, Inc., new P-wave 3D seismic interpretation methods to characterize fractured gas reservoirs are developed. A data driven exploratory approach is used to determine empirical relationships for reservoir properties. Fractures are predicted using seismic lineament mapping through a series of horizon and time slices in the reservoir zone. A seismic lineament is a linear feature seen in a slice through the seismic volume that has negligible vertical offset. We interpret that in regions of high seismic lineament density there is a greater likelihood of fractured reservoir. Seismic AVO attributes are developed to map brittle reservoir rock (low clay) and gas content. Brittle rocks are interpreted to be more fractured when seismic lineaments are present. The most important attribute developed in this study is the gas sensitive phase gradient (a new AVO attribute), as reservoir fractures may provide a plumbing system for both water and gas. Success is obtained when economic gas and oil discoveries are found. In a gas field previously plagued with poor drilling results, four new wells were spotted using the new methodology and recently drilled. The wells have estimated best of 12-months production indicators of 2106, 1652, 941, and 227 MCFGPD. The latter well was drilled in a region of swarming seismic lineaments but has poor gas sensitive phase gradient (AVO) and clay volume attributes. GeoSpectrum advised the unit operators that this location did not appear to have significant Lower Dakota gas before the well was drilled. The other three wells are considered good wells in this part of the basin and among the best wells in the area. These new drilling results have nearly doubled the gas production and the value of the field. The interpretation method is ready for commercialization and gas exploration and development. The new technology is adaptable to conventional lower cost 3D seismic surveys.

  4. Sex differences in cardiovascular function during submaximal exercise in humans.

    PubMed

    Wheatley, Courtney M; Snyder, Eric M; Johnson, Bruce D; Olson, Thomas P

    2014-01-01

    Differences in cardiovascular function between sexes have been documented at rest and maximal exercise. The purpose of this study was to examine the sex differences in cardiovascular function during submaximal constant-load exercise, which is not well understood. Thirty-one male and 33 female subjects completed nine minutes moderate and nine minutes vigorous intensity submaximal exercise (40 and 75% of peak watts determined by maximal exercise test). Measurements included: intra-arterial blood pressure (SBP and DBP), cardiac index (QI), heart rate (HR), oxygen consumption (VO2) and arterial catecholamines (epinephrine = EPI and norepinephrine = NE), and blood gases. Mean arterial pressure (MAP), stroke volume index (SVI), systemic vascular resistance index (SVRI), arterial oxygen content (CaO2), arterial to venous O2 difference (AVO2) and systemic oxygen transport (SOT) were calculated. At rest and during submaximal exercise QI, SVI, SBP, MAP, NE, CaO2, and SOT were lower in females compared to males. VO2, AVO2, EPI were lower in females throughout exercise. When corrected for wattage, females had a higher Q, HR, SV, VO2 and AVO2 despite lower energy expenditure and higher mechanical efficiency. This study demonstrates sex differences in the cardiovascular response to constant-load submaximal exercise. Specifically, females presented limitations in cardiac performance in which they are unable to compensate for reductions in stroke volume through increases in HR, potentially a consequence of a female's blunted sympathetic response and higher vasodilatory state. Females demonstrated greater cardiac work needed to meet the same external work demand, and relied on increased peripheral oxygen extraction, lower energy expenditure and improvements in mechanical efficiency as compensatory mechanisms. PMID:25191635

  5. Combining rock physics and sedimentology for seismic reservoir characterization of North Sea turbidite systems

    NASA Astrophysics Data System (ADS)

    Avseth, Per Age

    The petroleum industry is increasing its focus on the exploration of reservoirs in turbidite systems. However, these sedimentary environments are often characterized by very complex sand distributions. Hence, reservoir description based on conventional seismic and well-log interpretation may be very uncertain. There is a need to employ more quantitative seismic techniques to reveal reservoirs units in these complex systems from seismic amplitude data. In this study we focus on North Sea turbidite systems. Our goal is to improve the ability to use 3D seismic data to map reservoirs in these systems. A cross-disciplinary methodology for seismic reservoir characterization is presented that combines rock physics, sedimentology, and statistical techniques. We apply this methodology to two turbidite systems of Paleocene age located in the South Viking Graben of the North Sea. First, we investigate the relationship between sedimentary petrography and rock physics properties. Next, we define seismic scale sedimentary units, referred to as seismic lithofacies. These facies represent populations of data that have characteristic geologic and seismic properties. We establish a statistically representative training database by identifying seismic lithofacies from thin-sections, cores, and well-log data. This procedure is guided by diagnostic rock physics modeling. Based on the training data, we perform multivariate classification of data from several wells in the area. Next, we assess uncertainties in amplitude versus offset (AVO) response related to the inherent natural variability of each seismic lithofacies. We generate bivariate probability density functions (pdfs) of two AVO parameters for different facies combinations. By combining the bivariate pdfs estimated from well-logs with the AVO parameters estimated from seismic data, we use both quadratic discriminant analysis and Bayesian classification to predict lithofacies and pore fluids from seismic amplitudes. The final

  6. Quantitative seismic reservoir characterization of tight sands (granite wash) play at Stiles Ranch field in the Anadarko Basin, Texas (USA)

    NASA Astrophysics Data System (ADS)

    Durrani, Muhammad Zahid Afzal

    The main objective of this study is to conduct quantitative seismic reservoir characterization study of the Granite Wash (Marmaton-tight sand) play at Stiles Ranch field in the Anadarko Basin, Texas (USA). The proposed methodology incorporates seismic petrophysics, rock physics, Amplitude Variation with Offset (AVO) analysis and seismic pre-stack simultaneous elastic impedance inversion. In addition, it utilizes geostatistical technique to improve the reservoir property estimation and quantify uncertainty in seismic lithology and fluid prediction. The general objective encompasses several more specific goals to study: well data conditioning and prediction of essential petrophysical properties (e.g., porosity, permeability and saturation), and their relationship to the elastic properties. Due to the multidisciplinary nature of seismic petrophysics, only three core aspects are focused on that cover the desired objectives: 1) porosity modeling, 2) shear wave prediction, and (3) fluid substitution. The rock types are characterized by Rock Physics Diagnostic (RPD) approach conducted on well log data calibrated with core data and thin sections. The Granite Wash reservoir elastic properties are upscaled from log to seismic scale using Backus averaging to obtain a more coarsely (upscaled) sampled data set equivalent to the seismic scale. Anisotropy parametric (epsilon, gamma and delta) log curves are estimated consistent with seismic measurements using rock properties, seismic velocity and clay volume (Vsh) as a function of depth. The reservoir elastic properties are related to both the depositional environment and burial history through rock physics depth trends as function of depth. Furthermore, based on the practical aspects two separate inversion approaches; AVO and Elastic Impedance (EI) are evaluated prior to their application to real seismic. Various AVO derived attribute volumes such as intercept (A), gradient (B) and reflection coefficients (scaled Poisson's ratio

  7. Press Meeting 20 January 2003: First Light for Europe's Virtual Observatory

    NASA Astrophysics Data System (ADS)

    2002-12-01

    Imagine you are an astronomer with instant, fingertip access to all existing observations of a given object and the opportunity to sift through them at will. In just a few moments, you can have information on all kinds about objects out of catalogues all over the world, including observations taken at different times. Over the next two years this scenario will become reality as Europe's Astrophysical Virtual Observatory (AVO) develops. Established only a year ago (cf. ESO PR 26/01), the AVO already offers astronomers a unique, prototype research tool that will lead the way to many outstanding new discoveries. Journalists are invited to a live demonstration of the capabilities of this exciting new initiative in astronomy. The demonstration will take place at the Jodrell Bank Observatory in Manchester, in the United Kingdom, on 20 January 2003, starting at 11:00. Sophisticated AVO tools will help scientists find the most distant supernovae - objects that reveal the cosmological makeup of our Universe. The tools are also helping astronomers measure the rate of birth of stars in extremely red and distant galaxies. Journalists will also have the opportunity to discuss the project with leading astronomers from across Europe. The new AVO website has been launched today, explaining the progress being made in this European Commission-funded project: URL: http://www.euro-vo.org/ To register your intention to attend the AVO First Light Demonstration, please provide your name and affiliation by January 13, 2003, to: Ian Morison, Jodrell Bank Observatory (full contact details below). Information on getting to the event is included on the webpage above. Programme for the AVO First Light Demonstration 11:00 Welcome, Phil Diamond (University of Manchester/Jodrell Bank Observatory) 11:05 Short introduction to Virtual Observatories, Piero Benvenuti (ESA/ST-ECF) 11:15 Q&A 11:20 Short introduction to the Astrophysical Virtual Observatory, Peter Quinn (ESO) 11:30 Q&A 11:35 Screening of

  8. Predicting and validating the motion of an ash cloud during the 2006 eruption of Mount Augustine volcano

    USGS Publications Warehouse

    Collins, Richard L.; Fochesatto, Javier; Sassen, Kenneth; Webley, Peter W.; Atkinson, David E.; Dean, Kenneson G.; Cahill, Catherine F.; Mizutani, Kohei

    2007-01-01

    On 11 January 2006, Mount Augustine volcano in southern Alaska began erupting after 20- year repose. The Anchorage Forecast Office of the National Weather Service (NWS) issued an advisory on 28 January for Kodiak City. On 31 January, Alaska Airlines cancelled all flights to and from Anchorage after multiple advisories from the NWS for Anchorage and the surrounding region. The Alaska Volcano Observatory (AVO) had reported the onset of the continuous eruption. AVO monitors the approximately 100 active volcanoes in the Northern Pacific. Ash clouds from these volcanoes can cause serious damage to an aircraft and pose a serious threat to the local communities, and to transcontinental air traffic throughout the Arctic and sub-Arctic region. Within AVO, a dispersion model has been developed to track the dispersion of volcanic ash clouds. The model, Puff, was used operational by AVO during the Augustine eruptive period. Here, we examine the dispersion of a volcanic ash (or aerosol) cloud from Mount Augustine across Alaska from 29 January through the 2 February 2006. We present the synoptic meteorology, the Puff predictions, and measurements from aerosol samplers, laser radar (or lidar) systems, and satellites. Aerosol samplers revealed the presence of volcanic aerosols at the surface at sites where Puff predicted the ash clouds movement. Remote sensing satellite data showed the development of the ash cloud in close proximity to the volcano consistent with the Puff predictions. Two lidars showed the presence of volcanic aerosol with consistent characteristics aloft over Alaska and were capable of detecting the aerosol, even in the presence of scattered clouds and where the ash cloud is too thin/disperse to be detected by remote sensing satellite data. The lidar measurements revealed the different trajectories of ash consistent with the Puff predictions. Dispersion models provide a forecast of volcanic ash cloud movement that might be undetectable by any other means but are

  9. Press Meeting 20 January 2003: First Light for Europe's Virtual Observatory

    NASA Astrophysics Data System (ADS)

    2002-12-01

    Imagine you are an astronomer with instant, fingertip access to all existing observations of a given object and the opportunity to sift through them at will. In just a few moments, you can have information on all kinds about objects out of catalogues all over the world, including observations taken at different times. Over the next two years this scenario will become reality as Europe's Astrophysical Virtual Observatory (AVO) develops. Established only a year ago (cf. ESO PR 26/01), the AVO already offers astronomers a unique, prototype research tool that will lead the way to many outstanding new discoveries. Journalists are invited to a live demonstration of the capabilities of this exciting new initiative in astronomy. The demonstration will take place at the Jodrell Bank Observatory in Manchester, in the United Kingdom, on 20 January 2003, starting at 11:00. Sophisticated AVO tools will help scientists find the most distant supernovae - objects that reveal the cosmological makeup of our Universe. The tools are also helping astronomers measure the rate of birth of stars in extremely red and distant galaxies. Journalists will also have the opportunity to discuss the project with leading astronomers from across Europe. The new AVO website has been launched today, explaining the progress being made in this European Commission-funded project: URL: http://www.euro-vo.org/ To register your intention to attend the AVO First Light Demonstration, please provide your name and affiliation by January 13, 2003, to: Ian Morison, Jodrell Bank Observatory (full contact details below). Information on getting to the event is included on the webpage above. Programme for the AVO First Light Demonstration 11:00 Welcome, Phil Diamond (University of Manchester/Jodrell Bank Observatory) 11:05 Short introduction to Virtual Observatories, Piero Benvenuti (ESA/ST-ECF) 11:15 Q&A 11:20 Short introduction to the Astrophysical Virtual Observatory, Peter Quinn (ESO) 11:30 Q&A 11:35 Screening of

  10. Volcanic eruptions, hazardous ash clouds and visualization tools for accessing real-time infrared remote sensing data

    NASA Astrophysics Data System (ADS)

    Webley, P.; Dehn, J.; Dean, K. G.; Macfarlane, S.

    2010-12-01

    Volcanic eruptions are a global hazard, affecting local infrastructure, impacting airports and hindering the aviation community, as seen in Europe during Spring 2010 from the Eyjafjallajokull eruption in Iceland. Here, we show how remote sensing data is used through web-based interfaces for monitoring volcanic activity, both ground based thermal signals and airborne ash clouds. These ‘web tools’, http://avo.images.alaska.edu/, provide timely availability of polar orbiting and geostationary data from US National Aeronautics and Space Administration, National Oceanic and Atmosphere Administration and Japanese Meteorological Agency satellites for the North Pacific (NOPAC) region. This data is used operationally by the Alaska Volcano Observatory (AVO) for monitoring volcanic activity, especially at remote volcanoes and generates ‘alarms’ of any detected volcanic activity and ash clouds. The webtools allow the remote sensing team of AVO to easily perform their twice daily monitoring shifts. The web tools also assist the National Weather Service, Alaska and Kamchatkan Volcanic Emergency Response Team, Russia in their operational duties. Users are able to detect ash clouds, measure the distance from the source, area and signal strength. Within the web tools, there are 40 x 40 km datasets centered on each volcano and a searchable database of all acquired data from 1993 until present with the ability to produce time series data per volcano. Additionally, a data center illustrates the acquired data across the NOPAC within the last 48 hours, http://avo.images.alaska.edu/tools/datacenter/. We will illustrate new visualization tools allowing users to display the satellite imagery within Google Earth/Maps, and ArcGIS Explorer both as static maps and time-animated imagery. We will show these tools in real-time as well as examples of past large volcanic eruptions. In the future, we will develop the tools to produce real-time ash retrievals, run volcanic ash dispersion

  11. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2010

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Searcy, Cheryl K.

    2011-01-01

    Between January 1 and December 31, 2010, the Alaska Volcano Observatory (AVO) located 3,405 earthquakes, of which 2,846 occurred within 20 kilometers of the 33 volcanoes with seismograph subnetworks. There was no significant seismic activity in 2010 at these monitored volcanic centers. Seismograph subnetworks with severe outages in 2009 were repaired in 2010 resulting in three volcanic centers (Aniakchak, Korovin, and Veniaminof) being relisted in the formal list of monitored volcanoes. This catalog includes locations and statistics of the earthquakes located in 2010 with the station parameters, velocity models, and other files used to locate these earthquakes.

  12. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2005

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; McNutt, Stephen R.

    2006-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988 (Figure 1). The primary objectives of the seismic program are the real-time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents calculated earthquake hypocenters and seismic phase arrival data, and details changes in the seismic monitoring program for the period January 1 through December 31, 2005.The AVO seismograph network was used to monitor the seismic activity at thirty-two volcanoes within Alaska in 2005 (Figure 1). The network was augmented by two new subnetworks to monitor the Semisopochnoi Island volcanoes and Little Sitkin Volcano. Seismicity at these volcanoes was still being studied at the end of 2005 and has not yet been added to the list of permanently monitored volcanoes in the AVO weekly update. Following an extended period of monitoring to determine the background seismicity at the Mount Peulik, Ukinrek Maars, and Korovin Volcano, formal monitoring of these volcanoes began in 2005. AVO located 9,012 earthquakes in 2005.Monitoring highlights in 2005 include: (1) seismicity at Mount Spurr remaining above background, starting in February 2004, through the end of the year and into 2006; (2) an increase in seismicity at Augustine Volcano starting in May 2005, and continuing through the end of the year into 2006; (3) volcanic tremor and seismicity related to low-level strombolian activity at Mount Veniaminof in January to March and September; and (4) a seismic swarm at Tanaga Volcano in October and November.This catalog includes: (1) descriptions and locations of seismic instrumentation deployed in the field in 2005; (2) a

  13. Status of the VOTech Design Study about User Tools

    NASA Astrophysics Data System (ADS)

    Dolensky, M.; Pierfederici, F.; Allen, M.; Boch, T.; Bonnarel, F.; Derrière, S.; Fernique, P.; Noddle, K.; Smareglia, R.

    2006-07-01

    The VOTech design study on future tools started in spring 2005. This project, co-funded by the EC, produces design documents and software prototypes for new VO-compliant end-user tools. It is based on the experience and feedback of precursor projects and on input from the scientific user community. This status report details a number of early deliverables available from the project pages wiki.eurovotech.org, section DS4. This includes a summary of existing tools, desired future tools as derived from the AVO SRM, requirements for a cross matcher, a simple method for transferring instrumental footprints, use cases for simulations and the evaluation of various technologies.

  14. Predicting and validating the tracking of a Volcanic Ash Cloud during the 2006 Eruption of Mt. Augustine Volcano

    SciTech Connect

    Webley, Peter W.; Atkinson, D.; Collins, Richard L.; Dean, K.; Fochesatto, J.; Sassen, Kenneth; Cahill, Catherine F.; Prata, A.; Flynn, Connor J.; Mizutani, K.

    2008-11-01

    On 11 January 2006, Mount Augustine volcano in southern Alaska began erupting after 20-year repose. The Anchorage Forecast Office of the National Weather Service (NWS) issued an advisory on 28 January for Kodiak City. On 31 January, Alaska Airlines cancelled all flights to and from Anchorage after multiple advisories from the NWS for Anchorage and the surrounding region. The Alaska Volcano Observatory (AVO) had reported the onset of the continuous eruption. AVO monitors the approximately 100 active volcanoes in the Northern Pacific. Ash clouds from these volcanoes can cause serious damage to an aircraft and pose a serious threat to the local communities, and to transcontinental air traffic throughout the Arctic and sub-Arctic region. Within AVO, a dispersion model has been developed to track the dispersion of volcanic ash clouds. The model, Puff, was used operational by AVO during the Augustine eruptive period. Here, we examine the dispersion of a volcanic ash cloud from Mount Augustine across Alaska from 29 January through the 2 February 2006. We present the synoptic meteorology, the Puff predictions, and measurements from aerosol samplers, laser radar (or lidar) systems, and satellites. UAF aerosol samplers revealed the presence of volcanic aerosols at the surface at sites where Puff predicted the ash clouds movement. Remote sensing satellite data showed the development of the ash cloud in close proximity to the volcano and a sulfur-dioxide cloud further from the volcano consistent with the Puff predictions. Lidars showed the presence of volcanic aerosol with consistent characteristics aloft over Alaska and were capable of detecting the aerosol, even in the presence of scattered clouds and where the cloud is too thin/disperse to be detected by remote sensing satellite data. The lidar measurements revealed the different trajectories of ash consistent with the Puff predictions. Dispersion models provide a forecast of volcanic ash cloud movement that might be

  15. NON-INVASIVE DETERMINATION OF THE LOCATION AND DISTRIBUTION OF FREE-PHASE DENSE NONAQUEOUS PHASE LIQUIDS (DNAPL) BY SEISMIC REFLECTION TECHNIQUES

    SciTech Connect

    Michael G. Waddell; William J. Domoracki; Tom J. Temples; Jerome Eyer

    2001-05-01

    The Earth Sciences and Resources Institute, University of South Carolina is conducting a 14 month proof of concept study to determine the location and distribution of subsurface Dense Nonaqueous Phase Liquid (DNAPL) carbon tetrachloride (CCl{sub 4}) contamination at the 216-Z-9 crib, 200 West area, Department of Energy (DOE) Hanford Site, Washington by use of two-dimensional high resolution seismic reflection surveys and borehole geophysical data. The study makes use of recent advances in seismic reflection amplitude versus offset (AVO) technology to directly detect the presence of subsurface DNAPL. The techniques proposed are a noninvasive means towards site characterization and direct free-phase DNAPL detection. This report covers the results of Task 3 and change of scope of Tasks 4-6. Task 1 contains site evaluation and seismic modeling studies. The site evaluation consists of identifying and collecting preexisting geological and geophysical information regarding subsurface structure and the presence and quantity of DNAPL. The seismic modeling studies were undertaken to determine the likelihood that an AVO response exists and its probable manifestation. Task 2 is the design and acquisition of 2-D seismic reflection data designed to image areas of probable high concentration of DNAPL. Task 3 is the processing and interpretation of the 2-D data. Task 4, 5, and 6 were designing, acquiring, processing, and interpretation of a three dimensional seismic survey (3D) at the Z-9 crib area at 200 west area, Hanford.

  16. Performance comparison of streak camera recording systems

    SciTech Connect

    Derzon, M.; Barber, T.

    1995-07-01

    Streak camera based diagnostics are vital to the inertial confinement fusion program at Sandia National Laboratories. Performance characteristics of various readout systems coupled to an EGG-AVO streak camera were analyzed and compared to scaling estimates. The purpose of the work was to determine the limits of the streak camera performance and the optimal fielding conditions for the Amador Valley Operations (AVO) streak camera systems. The authors measured streak camera limitations in spatial resolution and sensitivity. Streak camera limits on spatial resolution are greater than 18 lp/mm at 4% contrast. However, it will be difficult to make use of any resolution greater than this because of high spatial frequency variation in the photocathode sensitivity. They have measured a signal to noise of 3,000 with 0.3 mW/cm{sup 2} of 830 nm light at a 10 ns/mm sweep speed. They have compared lens coupling systems with and without micro-channel plate intensifiers and systems using film or charge coupled device (CCD) readout. There were no conditions where film was found to be an improvement over the CCD readout. Systems utilizing a CCD readout without an intensifier have comparable resolution, for these source sizes and at a nominal cost in signal to noise of 3, over those with an intensifier. Estimates of the signal-to-noise for different light coupling methods show how performance can be improved.

  17. Analysis and improvement for a linearized seafloor elastic parameter inversion method

    NASA Astrophysics Data System (ADS)

    Liu, Yangting; Liu, Xuewei; Ning, Hongxiao

    2016-05-01

    AVO inversion is an effective seismic exploration method to predict elastic parameters. In this paper, we review and analyze the linearized AVO inversion method previously published for seafloor elastic parameters, and present a modification strategy. Before the linearized inversion is performed, a proper near-angle range in which the relationship between the reflection coefficient and sine-squared incidence angle is linear needs to be provided. However, the near-angle range is determined by the elastic parameters which are to be estimated by inversion. Therefore, only an approximated value of the near-angle range can be provided for the linearized inversion. Model tests show that a too large near-angle range may cause inversion fault, and a too small near-angle range may cause unreliable estimation. Further analysis shows that the estimation stability can be further improved even though the linearized inversion is performed under an exact near-angle range. To mitigate the strong dependence on the near-angle range, we use the seafloor elastic parameters estimated from the linearized method as the initial model for an unconstrained optimization method. Compared with the previously published method, the modified method is more robust to noisy data and shows less dependence on the near-angle range.

  18. Hibiscus sabdariffa leaf polyphenolic extract induces human melanoma cell death, apoptosis, and autophagy.

    PubMed

    Chiu, Chun-Tang; Hsuan, Shu-Wen; Lin, Hui-Hsuan; Hsu, Cheng-Chin; Chou, Fen-Pi; Chen, Jing-Hsien

    2015-03-01

    Melanoma is the least common but most fatal form of skin cancer. Previous studies have indicated that an aqueous extract of Hibiscus sabdariffa leaves possess hypoglycemic, hypolipidemic, and antioxidant effects. In this study, we want to investigate the anticancer activity of Hibiscus leaf polyphenolic (HLP) extract in melanoma cells. First, HLP was exhibited to be rich in epicatechin gallate (ECG) and other polyphenols. Apoptotic and autophagic activities of HLP and ECG were further evaluated by DAPI stain, cell-cycle analysis, and acidic vascular organelle (AVO) stain. Our results revealed that both HLP and ECG induced the caspases cleavages, Bcl-2 family proteins regulation, and Fas/FasL activation in A375 cells. In addition, we also revealed that the cells presented AVO-positive after HLP treatments. HLP could increase the expressions of autophagy-related proteins autophagy-related gene 5 (ATG5), Beclin1, and light chain 3-II (LC3-II), and induce autophagic cell death in A375 cells. These data indicated that the anticancer effect of HLP, partly contributed by ECG, in A375 cells. HLP potentially could be developed as an antimelanoma agent. PMID:25694272

  19. Carbonate reservoir characterization using seismic velocity and amplitude variation with offset analysis: Hardeman basin, Texas, test case

    SciTech Connect

    Pigott, J.D.; Shrestha, R.K. ); Warwick, R.A. )

    1991-03-01

    Mississippian bioherms in the Hardeman basin, Texas, produce from dolomitized mud cores with porosities that can vary from 10 to 40%. These carbonate buildups, though often similar in seismic reflector boundary configuration, can vary remarkably in reservoir quality (e.g., porosity) owing to diagenesis. However, imaging these lateral variations of porosity and determining the reservoir pressure is possible with detailed seismic velocity control and amplitude variation with offset (AVO) analysis. The investigated 24-fold seismic profile was acquired by four Vibroseis trucks in the Hardeman basin across two bioherms, one oil-productive and other tight and water-filled. Detailed stacking velocity analyses on the relative amplitude processed line directly delineate areas of increasing and decreasing gross porosity and dramatically differentiate the two mounds. Moreover, the detailed velocity analyses help provide a more accurate stacked section with resultant better definition of the external mound configuration. Analysis of available laboratory compressional and shear wave velocity data for carbonate rocks reveal that Young's modulus in carbonates is a function of porosity and differential pressure. Comparison of the derived Young's modulus from an inversion of the AVO data for the unstacked line with the experimental laboratory data yield porosity and differential pressure estimates over the productive bioherm which are within 18% and 15%, respectively, of those observed in the borehole.

  20. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2009

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Searcy, Cheryl K.

    2010-01-01

    Between January 1 and December 31, 2009, the Alaska Volcano Observatory (AVO) located 8,829 earthquakes, of which 7,438 occurred within 20 kilometers of the 33 volcanoes with seismograph subnetworks. Monitoring highlights in 2009 include the eruption of Redoubt Volcano, as well as unrest at Okmok Caldera, Shishaldin Volcano, and Mount Veniaminof. Additionally severe seismograph subnetwork outages resulted in four volcanoes (Aniakchak, Fourpeaked, Korovin, and Veniaminof) being removed from the formal list of monitored volcanoes in late 2009. This catalog includes descriptions of: (1) locations of seismic instrumentation deployed during 2009; (2) earthquake detection, recording, analysis, and data archival systems; (3) seismic velocity models used for earthquake locations; (4) a summary of earthquakes located in 2009; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, phase arrival times, location quality statistics, daily station usage statistics, all files used to determine the earthquake locations in 2009, and a dataless SEED volume for the AVO seismograph network.

  1. SEISMIC EVALUATION OF HYDROCARBON SATURATION IN DEEP-WATER RESERVOIRS

    SciTech Connect

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2005-08-12

    We are now entering the final stages of our ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342). We have now developed several techniques to help distinguish economic hydrocarbon deposits from false ''Fizz'' gas signatures. These methods include using the proper in situ rock and fluid properties, evaluating interference effects on data, and doing better constrained inversions for saturations. We are testing these techniques now on seismic data from several locations in the Gulf of Mexico. In addition, we are examining the use of seismic attenuation as indicated by frequency shifts below potential reservoirs. During this quarter we have: Began our evaluation of our latest data set over the Neptune Field; Developed software for computing composite reflection coefficients; Designed and implemented stochastic turbidite reservoir models; Produced software & work flow to improve frequency-dependent AVO analysis; Developed improved AVO analysis for data with low signal-to-noise ratio; and Examined feasibility of detecting fizz gas using frequency attenuation. Our focus on technology transfer continues, both by generating numerous presentations for the upcoming SEG annual meeting, and by beginning our planning for our next DHI minisymposium next spring.

  2. Kamchatkan Volcanic Eruption Response Team (KVERT), Russia: preventing the danger of volcanic eruptions to aviation.

    NASA Astrophysics Data System (ADS)

    Girina, O.; Neal, Ch.

    2012-04-01

    The Kamchatkan Volcanic Eruption Response Team (KVERT) has been a collaborative project of scientists from the Institute of Volcanology and Seismology, the Kamchatka Branch of Geophysical Surveys, and the Alaska Volcano Observatory (IVS, KB GS and AVO). The purpose of KVERT is to reduce the risk of costly, damaging, and possibly deadly encounters of aircraft with volcanic ash clouds. To reduce this risk, KVERT collects all possible volcanic information and issues eruption alerts to aviation and other emergency officials. KVERT was founded by Institute of Volcanic Geology and Geochemistry FED RAS in 1993 (in 2004, IVGG merged with the Institute of Volcanology to become IVS). KVERT analyzes volcano monitoring data (seismic, satellite, visual and video, and pilot reports), assigns the Aviation Color Code, and issues reports on eruptive activity and unrest at Kamchatkan (since 1993) and Northern Kurile (since 2003) volcanoes. KVERT receives seismic monitoring data from KB GS (the Laboratory for Seismic and Volcanic Activity). KB GS maintains telemetered seismic stations to investigate 11 of the most active volcanoes in Kamchatka. Data are received around the clock and analysts evaluate data each day for every monitored volcano. Satellite data are provided from several sources to KVERT. AVO conducts satellite analysis of the Kuriles, Kamchatka, and Alaska as part of it daily monitoring and sends the interpretation to KVERT staff. KVERT interprets MODIS and MTSAT images and processes AVHRR data to look for evidence of volcanic ash and thermal anomalies. KVERT obtains visual volcanic information from volcanologist's field trips, web-cameras that monitor Klyuchevskoy (established in 2000), Sheveluch (2002), Bezymianny (2003), Koryaksky (2009), Avachinsky (2009), Kizimen (2011), and Gorely (2011) volcanoes, and pilots. KVERT staff work closely with staff of AVO, AMC (Airport Meteorological Center) at Yelizovo Airport and the Tokyo Volcanic Ash Advisory Center (VAAC), the

  3. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2002

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sánchez, John; Estes, Steve; McNutt, Stephen R.; Paskievitch, John

    2003-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001; Dixon and others, 2002). The primary objectives of this program are the seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the basic seismic data and changes in the seismic monitoring program for the period January 1, 2002 through December 31, 2002. Appendix G contains a list of publications pertaining to seismicity of Alaskan volcanoes based on these and previously recorded data. The AVO seismic network was used to monitor twenty-four volcanoes in real time in 2002. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). Monitoring highlights in 2002 include an earthquake swarm at Great Sitkin Volcano in May-June; an earthquake swarm near Snowy Mountain in July-September; low frequency (1-3 Hz) tremor and long-period events at Mount Veniaminof in September-October and in December; and continuing volcanogenic seismic swarms at Shishaldin Volcano throughout the year. Instrumentation and data acquisition highlights in 2002 were the installation of a subnetwork on Okmok Volcano, the establishment of telemetry for the Mount Veniaminof subnetwork, and the change in the data acquisition system to

  4. Peak Oxygen Uptake during and after Long-duration Space Flight

    NASA Technical Reports Server (NTRS)

    Moore, Alan D., Jr.; Downs, Meghan E.; Lee, Stuart M. C.; Feiveson, Alan H.; Knudsen, Poul; Evetts, Simon N.; Ploutz-Snyder, Lori

    2014-01-01

    Aerobic capacity (VO2peak) previously has not been measured during or after long-duration spaceflight. PURPOSE: To measure VO2peak and submaximal exercise responses during and after International Space Station (ISS) missions. METHODS: Astronauts (9 M, 5 F: 49 +/- 5 yr, 175 +/- 7 cm, 77.2 +/- 15.1 kg, 40.6 +/- 6.4 mL/kg/min [mean +/-SD]) performed graded peak cycle tests 90 days before spaceflight, 15 d (FD15) after launch and every 30 d thereafter during flight, and 1 (R+1), 10 (R+10), and 30 d (R+30) after landing. Oxygen consumption (VO2) and heart rate (HR) were measured from rest to peak exercise, while cardiac output (Q), stroke volume (SV), and arterial-venous oxygen difference (a-vO2diff) were measured only during rest and submaximal exercise. Data were analyzed using mixed-model linear regression. Body mass contributed significantly to statistical models, and thus results are reported as modeled estimates for an average subject. RESULTS: Early inflight (FD15) VO2peak was 17% lower (95% CI = - 22%, -13%) than preflight. VO2peak increased during spaceflight (0.001 L/min/d, P = 0.02) but did not return to preflight levels. On R+1 VO2peak was 15% (95% CI = -19%, -10%) lower than preflight but recovered to within 2% of preflight by R+30 (95% CI = -6%, +3%). Peak HR was not significantly different from preflight at any time. Inflight submaximal VO2 and a-vO2diff were generally lower than preflight, but the Q vs. VO2 slope was unchanged. In contrast, the SV vs. VO2 slope was lower (P < 0.001), primarily due to elevated SV at rest, and the HR vs. VO2 slope was greater (P < 0.001), largely due to elevated HR during more intense exercise. On R+1 although the relationships between VO2 and Q, SV, and HR were not statistically different than preflight, resting and submaximal exercise SV was lower (P < 0.001), resting and submaximal exercise HR was higher (P < 0.002), and a-vO2diff was unchanged. HR and SV returned to preflight levels by R+30. CONCLUSION: In the average

  5. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2002

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sánchez, John; Estes, Steve; McNutt, Stephen R.; Paskievitch, John

    2003-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001; Dixon and others, 2002). The primary objectives of this program are the seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the basic seismic data and changes in the seismic monitoring program for the period January 1, 2002 through December 31, 2002. Appendix G contains a list of publications pertaining to seismicity of Alaskan volcanoes based on these and previously recorded data. The AVO seismic network was used to monitor twenty-four volcanoes in real time in 2002. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). Monitoring highlights in 2002 include an earthquake swarm at Great Sitkin Volcano in May-June; an earthquake swarm near Snowy Mountain in July-September; low frequency (1-3 Hz) tremor and long-period events at Mount Veniaminof in September-October and in December; and continuing volcanogenic seismic swarms at Shishaldin Volcano throughout the year. Instrumentation and data acquisition highlights in 2002 were the installation of a subnetwork on Okmok Volcano, the establishment of telemetry for the Mount Veniaminof subnetwork, and the change in the data acquisition system to

  6. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1, 2000 through December 31, 2001

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; Moran, Seth C.; Paskievitch, John; McNutt, Stephen R.

    2002-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at potentially active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog reflects the status and evolution of the seismic monitoring program, and presents the basic seismic data for the time period January 1, 2000, through December 31, 2001. For an interpretation of these data and previously recorded data, the reader should refer to several recent articles on volcano related seismicity on Alaskan volcanoes in Appendix G. The AVO seismic network was used to monitor twenty-three volcanoes in real time in 2000-2001. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). AVO located 1551 and 1428 earthquakes in 2000 and 2001, respectively, on and around these volcanoes. Highlights of the catalog period (Table 1) include: volcanogenic seismic swarms at Shishaldin Volcano between January and February 2000 and between May and June 2000; an eruption at Mount Cleveland between February and May 2001; episodes of possible tremor at Makushin Volcano starting March 2001 and continuing through 2001, and two earthquake swarms at Great Sitkin Volcano in 2001. This catalog includes: (1) earthquake origin

  7. Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs

    SciTech Connect

    Michael Batzle

    2006-04-30

    During this last period of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we finalized integration of rock physics, well log analysis, seismic processing, and forward modeling techniques. Most of the last quarter was spent combining the results from the principal investigators and come to some final conclusions about the project. Also much of the effort was directed towards technology transfer through the Direct Hydrocarbon Indicators mini-symposium at UH and through publications. As a result we have: (1) Tested a new method to directly invert reservoir properties, water saturation, Sw, and porosity from seismic AVO attributes; (2) Constrained the seismic response based on fluid and rock property correlations; (3) Reprocessed seismic data from Ursa field; (4) Compared thin layer property distributions and averaging on AVO response; (5) Related pressures and sorting effects on porosity and their influence on DHI's; (6) Examined and compared gas saturation effects for deep and shallow reservoirs; (7) Performed forward modeling using geobodies from deepwater outcrops; (8) Documented velocities for deepwater sediments; (9) Continued incorporating outcrop descriptive models in seismic forward models; (10) Held an open DHI symposium to present the final results of the project; (11) Relations between Sw, porosity, and AVO attributes; (12) Models of Complex, Layered Reservoirs; and (14) Technology transfer Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our

  8. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2003

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sanchez, John J.; McNutt, Stephen R.; Estes, Steve; Paskievitch, John

    2004-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988. The primary objectives of this program are the near real time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the calculated earthquake hypocenter and phase arrival data, and changes in the seismic monitoring program for the period January 1 through December 31, 2003.The AVO seismograph network was used to monitor the seismic activity at twenty-seven volcanoes within Alaska in 2003. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai volcanic cluster (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Okmok Caldera, Great Sitkin Volcano, Kanaga Volcano, Tanaga Volcano, and Mount Gareloi. Monitoring highlights in 2003 include: continuing elevated seismicity at Mount Veniaminof in January-April (volcanic unrest began in August 2002), volcanogenic seismic swarms at Shishaldin Volcano throughout the year, and low-level tremor at Okmok Caldera throughout the year. Instrumentation and data acquisition highlights in 2003 were the installation of subnetworks on Tanaga and Gareloi Islands, the installation of broadband installations on Akutan Volcano and Okmok Caldera, and the establishment of telemetry for the Okmok Caldera subnetwork. AVO located 3911 earthquakes in 2003.This catalog includes: (1) a description of instruments deployed in the field and their locations; (2) a

  9. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1, 2000 through December 31, 2001

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; Moran, Seth C.; Paskievitch, John; McNutt, Stephen R.

    2002-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at potentially active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog reflects the status and evolution of the seismic monitoring program, and presents the basic seismic data for the time period January 1, 2000, through December 31, 2001. For an interpretation of these data and previously recorded data, the reader should refer to several recent articles on volcano related seismicity on Alaskan volcanoes in Appendix G.The AVO seismic network was used to monitor twenty-three volcanoes in real time in 2000-2001. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). AVO located 1551 and 1428 earthquakes in 2000 and 2001, respectively, on and around these volcanoes.Highlights of the catalog period (Table 1) include: volcanogenic seismic swarms at Shishaldin Volcano between January and February 2000 and between May and June 2000; an eruption at Mount Cleveland between February and May 2001; episodes of possible tremor at Makushin Volcano starting March 2001 and continuing through 2001, and two earthquake swarms at Great Sitkin Volcano in 2001.This catalog includes: (1) earthquake origin times

  10. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2004

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; Prejean, Stephanie; Sanchez, John J.; Sanches, Rebecca; McNutt, Stephen R.; Paskievitch, John

    2005-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988. The primary objectives of the seismic program are the real-time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the calculated earthquake hypocenter and phase arrival data, and changes in the seismic monitoring program for the period January 1 through December 31, 2004.These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai volcanic cluster (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Mount Peulik, Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Okmok Caldera, Great Sitkin Volcano, Kanaga Volcano, Tanaga Volcano, and Mount Gareloi. Over the past year, formal monitoring of Okmok, Tanaga and Gareloi were announced following an extended period of monitoring to determine the background seismicity at each volcanic center. The seismicity at Mount Peulik was still being studied at the end of 2004 and has yet to be added to the list of monitored volcanoes in the AVO weekly update. AVO located 6928 earthquakes in 2004.Monitoring highlights in 2004 include: (1) an earthquake swarm at Westdahl Peak in January; (2) an increase in seismicity at Mount Spurr starting in February continuing through the end of the year into 2005; (4) low-level tremor, and low-frequency events related to intermittent ash and steam emissions at Mount Veniaminof between April and October; (4) low-level tremor at Shishaldin Volcano between April and

  11. Relationships between hemodynamic, hemorheological and metabolic responses during exercise.

    PubMed

    Connes, Philippe; Tripette, Julien; Mukisi-Mukaza, Martin; Baskurt, Oguz K; Toth, Kalman; Meiselman, Herbert J; Hue, Olivier; Antoine-Jonville, Sophie

    2009-01-01

    Aerobic performance is dependent on both cardio-respiratory and peripheral factors with hemodynamic parameters playing a major role. However, whether blood rheology might affect aerobic performance through an effect on hemodynamic factors is not known. The aim of the present study was to assess the relationships between hemodynamic, hemorheological and metabolic parameters in response to a sub-maximal cycling exercise protocol consisting of three successive levels of nine min duration (50, 100 and 150 W). Ten young sportsmen participated in the present study. Mean arterial pressure (MAP) was measured manually, with thoracic impedance used to monitor cardiac output (Qc): systemic vascular resistance (SVR) was then calculated. Whole blood viscosity (etab) was measured and used to calculate systemic vascular hindrance. Hematocrit (Hct) was determined by micro-centrifugation and red blood cell (RBC) deformability (EI) was determined by ecktacytometry. A breath-by-breath gas analyzer was used to measure oxygen uptake (VO2); the Fick equation was used to calculate arterio-venous oxygen difference [(a-v)O(2)] from VO(2) and Qc. All measurements were performed at rest, during exercise and during recovery. Compared to baseline, Qc, MAP, Hct, EI, VO(2), and (a-v)O(2) increased during exercise. etab increased above baseline only at 150 W and remained elevated during recovery; the increase in etab during the last level of exercise was associated with a decrease of SVR and systemic vascular hindrance. There was a significant negative correlation between EI and SVR (r=-0.35, p<0.01) and a significant positive relationship between EI and (a-v)O(2) (r=0.35, p<0.01) and between EI and VO(2) (r=0.37, p<0.01) across all exercise workloads, thus suggesting a potential role for RBC deformability as a factor affecting aerobic performance via oxygen delivery to tissues. These data lend support to the concept that hemorheological parameters may contribute to hemodynamic and cardio

  12. Alaska - Russian Far East connection in volcano research and monitoring

    NASA Astrophysics Data System (ADS)

    Izbekov, P. E.; Eichelberger, J. C.; Gordeev, E.; Neal, C. A.; Chebrov, V. N.; Girina, O. A.; Demyanchuk, Y. V.; Rybin, A. V.

    2012-12-01

    The Kurile-Kamchatka-Alaska portion of the Pacific Rim of Fire spans for nearly 5400 km. It includes more than 80 active volcanoes and averages 4-6 eruptions per year. Resulting ash clouds travel for hundreds to thousands of kilometers defying political borders. To mitigate volcano hazard to aviation and local communities, the Alaska Volcano Observatory (AVO) and the Institute of Volcanology and Seismology (IVS), in partnership with the Kamchatkan Branch of the Geophysical Survey of the Russian Academy of Sciences (KBGS), have established a collaborative program with three integrated components: (1) volcano monitoring with rapid information exchange, (2) cooperation in research projects at active volcanoes, and (3) volcanological field schools for students and young scientists. Cooperation in volcano monitoring includes dissemination of daily information on the state of volcanic activity in neighboring regions, satellite and visual data exchange, as well as sharing expertise and technologies between AVO and the Kamchatkan Volcanic Eruption Response Team (KVERT) and Sakhalin Volcanic Eruption Response Team (SVERT). Collaboration in scientific research is best illustrated by involvement of AVO, IVS, and KBGS faculty and graduate students in mutual international studies. One of the most recent examples is the NSF-funded Partnerships for International Research and Education (PIRE)-Kamchatka project focusing on multi-disciplinary study of Bezymianny volcano in Kamchatka. This international project is one of many that have been initiated as a direct result of a bi-annual series of meetings known as Japan-Kamchatka-Alaska Subduction Processes (JKASP) workshops that we organize together with colleagues from Hokkaido University, Japan. The most recent JKASP meeting was held in August 2011 in Petropavlovsk-Kamchatsky and brought together more than 130 scientists and students from Russia, Japan, and the United States. The key educational component of our collaborative program

  13. Seismic constraints on the nature of lower crustal reflectors beneath the extending Southern Transition Zone of the Colorado Plateau, Arizona

    USGS Publications Warehouse

    Parsons, Thomas E.; Howie, John M.; Thompson, George A.

    1992-01-01

    We determine the reflection polarity and exploit variations in P and S wave reflectivity and P wave amplitude versus offset (AVO) to constrain the origin of lower crustal reflectivity observed on new three-component seismic data recorded across the structural transition of the Colorado Plateau. The near vertical incidence reflection data were collected by Stanford University in 1989 as part of the U.S. Geological Survey Pacific to Arizona Crustal Experiment that traversed the Arizona Transition Zone of the Colorado Plateau. The results of independent waveform modeling methods are consistent with much of the lower crustal reflectivity resulting from thin, high-impedance layers. The reflection polarity of the cleanest lower crustal events is positive, which implies that these reflections result from high-velocity contrasts, and the waveform character indicates that the reflectors are probably layers less than or approximately equal to 200 m thick. The lower crustal events are generally less reflective to incident S waves than to P waves, which agrees with the predicted behavior of high-velocity mafic layering. Analysis of the P wave AVO character of lower crustal reflections demonstrates that the events maintain a constant amplitude with offset, which is most consistent with a mafic-layering model. One exception is a high-amplitude (10 dB above background) event near the base of lower crustal reflectivity which abruptly decreases in amplitude at increasing offsets. The event has a pronounced S wave response, which along with its negative AVO trend is a possible indication of the presence of fluids in the lower crust. The Arizona Transition Zone is an active but weakly extended province, which causes us to discard models of lower crustal layering resulting from shearing because of the high degree of strain required to create such layers. Instead, we favor horizontal basaltic intrusions as the primary origin of high-impedance reflectors based on (1) The fact that

  14. Exploring the Digital Universe with Europe's Astrophysical Virtual Observatory

    NASA Astrophysics Data System (ADS)

    2001-12-01

    Vast Databanks at the Astronomers' Fingertips Summary A new European initiative called the Astrophysical Virtual Observatory (AVO) is being launched to provide astronomers with a breathtaking potential for new discoveries. It will enable them to seamlessly combine the data from both ground- and space-based telescopes which are making observations of the Universe across the whole range of wavelengths - from high-energy gamma rays through the ultraviolet and visible to the infrared and radio. The aim of the Astrophysical Virtual Observatory (AVO) project, which started on 15 November 2001, is to allow astronomers instant access to the vast databanks now being built up by the world's observatories and which are forming what is, in effect, a "digital sky" . Using the AVO, astronomers will, for example, be able to retrieve the elusive traces of the passage of an asteroid as it passes near the Earth and so enable them to predict its future path and perhaps warn of a possible impact. When a giant star comes to the end of its life in a cataclysmic explosion called a supernova, they will be able to access the digital sky and pinpoint the star shortly before it exploded so adding invaluable data to the study of the evolution of stars. Background information on the Astrophysical Virtual Observatory is available in the Appendix. PR Photo 34a/01 : The Astrophysical Virtual Observatory - an artist's impression. The rapidly accumulating database ESO PR Photo 34a/01 ESO PR Photo 34a/01 [Preview - JPEG: 400 x 345 pix - 90k] [Normal - JPEG: 800 x 689 pix - 656k] [Hi-Res - JPEG: 3000 x 2582 pix - 4.3M] ESO PR Photo 34a/01 shows an artist's impression of the Astrophysical Virtual Observatory . Modern observatories observe the sky continuously and data accumulates remorselessly in the digital archives. The growth rate is impressive and many hundreds of terabytes of data - corresponding to many thousands of billions of pixels - are already available to scientists. The real sky is being

  15. Fylla complex -- Possible very large gas reserves off S. W. Greenland

    SciTech Connect

    Bate, K.J.; Whittaker, R.C.; Chalmers, J.A.; Dahl-Jensen, T. )

    1994-08-22

    Recent interpretation of new seismic data acquired off southern West Greenland has identified a number of structural leads with accumulated potential gas reserves that may be of the order of 100 tcf. The presence of two flat-spots with clear amplitude versus offset (AVO) effects overlying a possible oil column is the most direct indication of the occurrence of gas in the area. A total of seven individual structural leads have been identified underlying the fylla bank, covering an area 130 by 60 km, within what has been termed the Fylla structural complex. All the leads are in the form of large tilted fault blocks created in the Early Tertiary and draped by Paleocene and Eocene mudstones. The paper discusses the region's geological development and direct hydrocarbon indicators.

  16. WFPDB: European Plate Archives

    NASA Astrophysics Data System (ADS)

    Tsvetkov, Milcho

    2007-08-01

    The Wide-Field Plate Database (WFPDB) gives an inventory of all wide-field (>~ 1 sq. deg) photographic observations archived in astronomical institutions over the world. So it facilitates and stimulates their use and preservation as a valuable source of information for future investigations in astronomy. At present WFPDB manages plate-index information for 25% of all existing plates providing on-line access from Sofia (http://www.skyarchive.org/search) and in CDS, Strasbourg. Here we present the new development of WFPDB as an instrument for searching of long term brightness variations of different sky objects stressing on the European photographic plate collections (from existing 2 million wide-field plates more than 55% are in Europe: Germany, Russia, Ukraine, Italy, Czech Republic, etc.). We comment examples of digitization (with flatbed scanners) of the European plate archives in Sonneberg, Pulkovo, Asiago, Byurakan, Bamberg, etc. and virtual links of WFPDB with European AVO, ADS, IBVS.

  17. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1, 1994 through December 31, 1999

    USGS Publications Warehouse

    Jolly, Arthur D.; Stihler, Scott D.; Power, John A.; Lahr, John C.; Paskievitch, John; Tytgat, Guy; Estes, Steve; Lockhart, Andrew B.; Moran, Seth C.; McNutt, Stephen R.; Hammond, William R.

    2001-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska - Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained a seismic monitoring program at potentially active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. Between 1994 and 1999, the AVO seismic monitoring program underwent significant changes with networks added at new volcanoes during each summer from 1995 through 1999. The existing network at Katmai –Valley of Ten Thousand Smokes (VTTS) was repaired in 1995, and new networks were installed at Makushin (1996), Akutan (1996), Pavlof (1996), Katmai - south (1996), Aniakchak (1997), Shishaldin (1997), Katmai - north (1998), Westdahl, (1998), Great Sitkin (1999) and Kanaga (1999). These networks added to AVO's existing seismograph networks in the Cook Inlet area and increased the number of AVO seismograph stations from 46 sites and 57 components in 1994 to 121 sites and 155 components in 1999. The 1995–1999 seismic network expansion increased the number of volcanoes monitored in real-time from 4 to 22, including Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Mount Snowy, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin, Aniakchak Crater, Pavlof Volcano, Mount Dutton, Isanotski volcano, Shisaldin Volcano, Fisher Caldera, Westdahl volcano, Akutan volcano, Makushin Volcano, Great Sitkin volcano, and Kanaga Volcano (see Figures 1-15). The network expansion also increased the number of earthquakes located from about 600 per year in1994 and 1995 to about 3000 per year between 1997 and 1999. Highlights of the catalog period include: 1) a large volcanogenic seismic

  18. NON-INVASIVE DETERMINATION OF THE LOCATION AND DISTRBUTION OF FREE-PHASE DENSE NONAQUEOUS PHASE LIQUIDS (DNAPL) BY SEISMIC REFLECTION TECHNIQUES

    SciTech Connect

    Michael G. Waddell; William J. Domoracki; Jerome Eyer

    2003-01-01

    The Earth Sciences and Resources Institute, University of South Carolina is conducting a proof of concept study to determine the location and distribution of subsurface DNAPL carbon tetrachloride (CCl{sub 4}) contamination at the 216-Z-9 crib, 200 West area, DOE Hanford Site, Washington by use of two-dimensional high-resolution seismic reflection surveys and borehole geophysical data. The study makes use of recent advances in seismic reflection amplitude versus offset (AVO) technology to directly detect the presence of subsurface DNAPL. The techniques proposed are noninvasive means of site characterization and direct free-phase DNAPL detection. This final report covers the results of Tasks 1, 2, and 3. Task (1) contains site evaluation and seismic modeling studies. The site evaluation consists of identifying and collecting preexisting geological and geophysical information regarding subsurface structure and the presence and quantity of DNAPL. The seismic modeling studies were undertaken to determine the likelihood that an AVO response exists and its probable manifestation. Task (2) is the design and acquisition of 2-D seismic reflection data to image areas of probable high concentration of DNAPL. Task (3) is the processing and interpretation of the 2-D data. During the commission of these tasks four seismic reflection profiles were collected. Subsurface velocity information was obtained by vertical seismic profile surveys in three wells. The interpretation of these data is in two parts. Part one is the construction and interpretation of structural contour maps of the contact between the Hanford Fine unit and the underlying Plio/Pleistocene unit and of the contact between the Plio/Pleistocene unit and the underlying caliche layer. These two contacts were determined to be the most likely surfaces to contain the highest concentration CCl{sub 4}. Part two of the interpretation uses the results of the AVO modeling to locate any seismic amplitude anomalies that might be

  19. The next generation of shared seismic models for R&D.

    SciTech Connect

    Marfurt, K. J.; Wiley, R.; Martin, G. S.; House, L. S.; Larsen, S. C.

    2002-01-01

    We have created several elastic 2-D models and are currently defining a complex 3D elastic salt model for distribution to the international research community for use in the calibration of AVO, polarization filtering, tomography, multicomponent seismic analysis, converted wave tomography, and seismic attribute analysis. We have also obtained the release of several real 2-D data sets corresponding to the 2-D models to test the robustness of any new techniques. In addition to the synthetic seismograms generated over these models, we will release the model definition of layers and rock properties to the research community so that others may modify them to include features beyond the scope of our current effort, such as gas clouds, fractures, and diagenetic changes. Finally, we expect these models to serve as a test bed for impmving the computational efficiency of elastic mode ling as a goal in itself.

  20. Markov Chain Monte Carlo Sampling Methods for 1D Seismic and EM Data Inversion

    Energy Science and Technology Software Center (ESTSC)

    2008-09-22

    This software provides several Markov chain Monte Carlo sampling methods for the Bayesian model developed for inverting 1D marine seismic and controlled source electromagnetic (CSEM) data. The current software can be used for individual inversion of seismic AVO and CSEM data and for joint inversion of both seismic and EM data sets. The structure of the software is very general and flexible, and it allows users to incorporate their own forward simulation codes and rockmore » physics model codes easily into this software. Although the softwae was developed using C and C++ computer languages, the user-supplied codes can be written in C, C++, or various versions of Fortran languages. The software provides clear interfaces for users to plug in their own codes. The output of this software is in the format that the R free software CODA can directly read to build MCMC objects.« less

  1. Trace cable, locate faults with one instrument

    SciTech Connect

    Arias, A. )

    1994-12-01

    One of the problems with cable-tracing instruments that use radio-frequency (RF) signals is that they tend to radiate to nontarget conductors belonging to other utilities, such as telecommunications, gas, and cable TV. False readings generated by these RF units put repair crews at risk of locating the wrong lines, marking them, digging them up and so damaging another company's facilities. Crews at Florida Power Light Co (FP L) now are using a microprocessor-controlled transmitter that energizes the target cable at about 7776 Hz. This tracing frequency energizes only the secondary cable, even when nontarget conductors are nearby. An above-ground receiver detects this signal and guides the operator along the cable path. The instrument, known as the SFL-2000, is sold by AVO International, Blue Bell, Pa. 3 figs.

  2. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1, 1994 through December 31, 1999

    USGS Publications Warehouse

    Jolly, Arthur D.; Stihler, Scott D.; Power, John A.; Lahr, John C.; Paskievitch, John; Tytgat, Guy; Estes, Steve; Lockhart, Andrew B.; Moran, Seth C.; McNutt, Stephen R.; Hammond, William R.

    2001-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska - Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained a seismic monitoring program at potentially active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism.Between 1994 and 1999, the AVO seismic monitoring program underwent significant changes with networks added at new volcanoes during each summer from 1995 through 1999. The existing network at Katmai –Valley of Ten Thousand Smokes (VTTS) was repaired in 1995, and new networks were installed at Makushin (1996), Akutan (1996), Pavlof (1996), Katmai - south (1996), Aniakchak (1997), Shishaldin (1997), Katmai - north (1998), Westdahl, (1998), Great Sitkin (1999) and Kanaga (1999). These networks added to AVO's existing seismograph networks in the Cook Inlet area and increased the number of AVO seismograph stations from 46 sites and 57 components in 1994 to 121 sites and 155 components in 1999. The 1995–1999 seismic network expansion increased the number of volcanoes monitored in real-time from 4 to 22, including Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Mount Snowy, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin, Aniakchak Crater, Pavlof Volcano, Mount Dutton, Isanotski volcano, Shisaldin Volcano, Fisher Caldera, Westdahl volcano, Akutan volcano, Makushin Volcano, Great Sitkin volcano, and Kanaga Volcano (see Figures 1-15). The network expansion also increased the number of earthquakes located from about 600 per year in1994 and 1995 to about 3000 per year between 1997 and 1999.Highlights of the catalog period include: 1) a large volcanogenic seismic

  3. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2007

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.

    2008-01-01

    Between January 1 and December 31, 2007, AVO located 6,664 earthquakes of which 5,660 occurred within 20 kilometers of the 33 volcanoes monitored by the Alaska Volcano Observatory. Monitoring highlights in 2007 include: the eruption of Pavlof Volcano, volcanic-tectonic earthquake swarms at the Augustine, Illiamna, and Little Sitkin volcanic centers, and the cessation of episodes of unrest at Fourpeaked Mountain, Mount Veniaminof and the northern Atka Island volcanoes (Mount Kliuchef and Korovin Volcano). This catalog includes descriptions of : (1) locations of seismic instrumentation deployed during 2007; (2) earthquake detection, recording, analysis, and data archival systems; (3) seismic velocity models used for earthquake locations; (4) a summary of earthquakes located in 2007; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, phase arrival times, location quality statistics, daily station usage statistics, and all files used to determine the earthquake locations in 2007.

  4. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2006

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Searcy, Cheryl

    2008-01-01

    Between January 1 and December 31, 2006, AVO located 8,666 earthquakes of which 7,783 occurred on or near the 33 volcanoes monitored within Alaska. Monitoring highlights in 2006 include: an eruption of Augustine Volcano, a volcanic-tectonic earthquake swarm at Mount Martin, elevated seismicity and volcanic unrest at Fourpeaked Mountain, and elevated seismicity and low-level tremor at Mount Veniaminof and Korovin Volcano. A new seismic subnetwork was installed on Fourpeaked Mountain. This catalog includes: (1) descriptions and locations of seismic instrumentation deployed in the field during 2006, (2) a description of earthquake detection, recording, analysis, and data archival systems, (3) a description of seismic velocity models used for earthquake locations, (4) a summary of earthquakes located in 2006, and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, phase arrival times, location quality statistics, daily station usage statistics, and all files used to determine the earthquake locations in 2006.

  5. SEISMIC MODELING ENGINES PHASE 1 FINAL REPORT

    SciTech Connect

    BRUCE P. MARION

    2006-02-09

    Seismic modeling is a core component of petroleum exploration and production today. Potential applications include modeling the influence of dip on anisotropic migration; source/receiver placement in deviated-well three-dimensional surveys for vertical seismic profiling (VSP); and the generation of realistic data sets for testing contractor-supplied migration algorithms or for interpreting AVO (amplitude variation with offset) responses. This project was designed to extend the use of a finite-difference modeling package, developed at Lawrence Berkeley Laboratories, to the advanced applications needed by industry. The approach included a realistic, easy-to-use 2-D modeling package for the desktop of the practicing geophysicist. The feasibility of providing a wide-ranging set of seismic modeling engines was fully demonstrated in Phase I. The technical focus was on adding variable gridding in both the horizontal and vertical directions, incorporating attenuation, improving absorbing boundary conditions and adding the optional coefficient finite difference methods.

  6. The Rock Physics Handbook

    NASA Astrophysics Data System (ADS)

    Mavko, Gary; Mukerji, Tapan; Dvorkin, Jack

    2003-10-01

    The Rock Physics Handbook conveniently brings together the theoretical and empirical relations that form the foundations of rock physics, with particular emphasis on seismic properties. It also includes commonly used models and relations for electrical and dielectric rock properties. Seventy-six articles concisely summarize a wide range of topics, including wave propagation, AVO-AVOZ, effective media, poroelasticity, pore fluid flow and diffusion. The book contains overviews of dispersion mechanisms, fluid substitution, and Vp-Vs relations. Useful empirical results on reservoir rocks and sediments, granular media, tables of mineral data, and an atlas of reservoir rock properties complete the text. This distillation of an otherwise scattered and eclectic mass of knowledge is presented in a form that can be immediately applied to solve real problems. Geophysics professionals, researchers and students as well as petroleum engineers, well log analysts, and environmental geoscientists will value The Rock Physics Handbook as a unique resource.

  7. Monitoring volcanic threats using ASTER satellite data

    USGS Publications Warehouse

    Duda, K.A.; Wessels, R.; Ramsey, M.; Dehn, J.

    2008-01-01

    This document summarizes ongoing activities associated with a research project funded by the National Aeronautics and Space Administration (NASA) focusing on volcanic change detection through the use of satellite imagery. This work includes systems development as well as improvements in data analysis methods. Participating organizations include the NASA Land Processes Distributed Active Archive Center (LP DAAC) at the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS), the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Science Team, the Alaska Volcano Observatory (AVO) at the USGS Alaska Science Center, the Jet Propulsion Laboratory/California Institute of Technology (JPL/CalTech), the University of Pittsburgh, and the University of Alaska Fairbanks. ?? 2007 IEEE.

  8. SEISMIC EVALUATION OF HYDROCARBON SATURATION IN DEEP-WATER RESERVOIRS

    SciTech Connect

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2005-01-22

    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we have moved forward on several fronts, including data acquisition as well as analysis and application. During this quarter we have: (1) Completed our site selection (finally); (2) Measured fluid effects in Troika deep water sand sample; (3) Applied the result to Ursa ''fizz gas'' zone; (4) Compared thin layer property averaging on AVO response; (5) Developed target oriented NMO stretch correction; (6) Examined thin bed effects on A-B crossplots; and (7) Begun incorporating outcrop descriptive models in seismic forward models. Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our hydrocarbon indicators. Reservoirs composed of thin bed effects will broaden the reflection amplitude distribution with incident angle. Normal move out (NMO) stretch corrections based on frequency shifts can be applied to offset this effect. Tuning will also disturb the location of extracted amplitudes on AVO intercept and gradient (A-B) plots. Many deep water reservoirs fall this tuning thickness range. Our goal for the remaining project period is to systematically combine and document these various effects for use in deep water exploration.

  9. Systemic and vastus lateralis muscle blood flow and O2 extraction during ramp incremental cycle exercise.

    PubMed

    Murias, Juan M; Spencer, Matthew D; Keir, Daniel A; Paterson, Donald H

    2013-05-01

    During ramp incremental cycling exercise increases in pulmonary O2 uptake (Vo2p) are matched by a linear increase in systemic cardiac output (Q). However, it has been suggested that blood flow in the active muscle microvasculature does not display similar linearity in blood flow relative to metabolic demand. This study simultaneously examined both systemic and regional (microvascular) blood flow and O2 extraction during incremental cycling exercise. Ten young men (Vo2 peak = 4.2 ± 0.5 l/min) and 10 young women (Vo2 peak = 3.2 ± 0.5 l/min) were recruited to perform two maximal incremental cycling tests on separate days. The acetylene open-circuit technique and mass spectrometry and volume turbine were used to measure Q (every minute) and breath-by-breath Vo2p, respectively; systemic arterio-venous O2 difference (a-vO2diff) was calculated as Vo2p/Q on a minute-by-minute basis. Changes in near-infrared spectroscopy-derived muscle deoxygenation (Δ[HHb]) were used (in combination with Vo2p data) to estimate the profiles of peripheral O2 extraction and blood flow of the active muscle microvasculature. The systemic Q-to-Vo2p relationship was linear (~5.8 l/min increase in Q for a 1 l/min increase in Vo2p) with a-vO2diff displaying a hyperbolic response as exercise intensity increased toward Vo2 peak. The peripheral blood flow response profile was described by an inverted sigmoid curve, indicating nonlinear responses relative to metabolic demand. The Δ[HHb] profile increased linearly with absolute Vo2p until high-intensity exercise, thereafter displaying a "near-plateau". Results indicate that systemic blood flow and thus O2 delivery does not reflect the profile of blood flow changes at the level of the microvasculature. PMID:23515617

  10. PBO Operations in Alaska and Cascadia, Combining Regions and Collaborating with our Regional Partners

    NASA Astrophysics Data System (ADS)

    Austin, K. E.; Boyce, E. S.; Dausz, K.; Feaux, K.; Mattioli, G. S.; Pyatt, C.; Willoughby, H.; Woolace, A. C.

    2015-12-01

    During the last year, the Alaska and the Cascadia regions of the EarthScope Plate Boundary Observatory (PBO) network were combined into a single management unit. While both remain distinct regions with their own challenges and engineering staff, every effort has been made to operate as a single team to improve efficiency and provide the highest possible data quality and uptime. Over the last several years a concerted effort has been made to work collaboratively with other institutions and stakeholders to defray ongoing costs by sharing staff and resources. UNAVCO currently operates four integrated GPS/seismic stations in collaboration with the Alaska Earthquake Center, eight with the Alaska Volcano Observatory, and three with the EarthScope TA. By the end of 2015, PBO and TA plan to install another 3 integrated and/or co-located geodetic and seismic systems. While most of these are designed around existing PBO stations, the 2014 installation at Middleton Island is a new station for both groups, providing PBO with an opportunity to expand geodetic data in Alaska. There were two major joint maintenance efforts in 2015:, the largest was a 5 day mission among PBO, AVO, and TA, which shared boat, helicopter, and staff on and around Augustine Volcano; the second, was a 10 day helicopter mission shared between AVO and PBO on Unimak Island. PBO Pacific Northwest is working closely with University of Washington to co-locate at least 9 Earthquake Early Warning Systems, which include the addition of strong motion sensors and high speed RT telemetry at PBO sites. The project is managed by University of Washington but UNAVCO is providing land contact information and infrastructure support. Summer 2015 upgrades include a complete overhaul of aging radio technology at two major networks and several small radio networks in Cascadia. The upgrades will increase reliability and enhance the speed of existing telemetry infrastructure and will continue through summer 2018.

  11. Seismic Evaluation of Hydorcarbon Saturation in Deep-Water Reservoirs

    SciTech Connect

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2005-10-31

    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we have moved forward on several fronts, including data acquisition as well as analysis and application. During this quarter we have: (1) Completed our site selection (finally); (2) Measured fluid effects in Troika deep water sand sample; (3) Applied the result to Ursa ''fizz gas'' zone; (4) Compared thin layer property averaging on AVO response; (5) Developed target oriented NMO stretch correction; (6) Examined thin bed effects on A-B crossplots; and (7) Begun incorporating outcrop descriptive models in seismic forward models. Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our hydrocarbon indicators. Reservoirs composed of thin bed effects will broaden the reflection amplitude distribution with incident angle. Normal move out (NMO) stretch corrections based on frequency shifts can be applied to offset this effect. Tuning will also disturb the location of extracted amplitudes on AVO intercept and gradient (A-B) plots. Many deep water reservoirs fall this tuning thickness range. Our goal for the remaining project period is to systematically combine and document these various effects for use in deep water exploration.

  12. A volcanic activity alert-level system for aviation: review of its development and application in Alaska

    USGS Publications Warehouse

    2013-01-01

    An alert-level system for communicating volcano hazard information to the aviation industry was devised by the Alaska Volcano Observatory (AVO) during the 1989–1990 eruption of Redoubt Volcano. The system uses a simple, color-coded ranking that focuses on volcanic ash emissions: Green—normal background; Yellow—signs of unrest; Orange—precursory unrest or minor ash eruption; Red—major ash eruption imminent or underway. The color code has been successfully applied on a regional scale in Alaska for a sustained period. During 2002–2011, elevated color codes were assigned by AVO to 13 volcanoes, eight of which erupted; for that decade, one or more Alaskan volcanoes were at Yellow on 67 % of days and at Orange or Red on 12 % of days. As evidence of its utility, the color code system is integrated into procedures of agencies responsible for air-traffic management and aviation meteorology in Alaska. Furthermore, it is endorsed as a key part of globally coordinated protocols established by the International Civil Aviation Organization to provide warnings of ash hazards to aviation worldwide. The color code and accompanying structured message (called a Volcano Observatory Notice for Aviation) comprise an effective early-warning message system according to the United Nations International Strategy for Disaster Reduction. The aviation color code system currently is used in the United States, Russia, New Zealand, Iceland, and partially in the Philippines, Papua New Guinea, and Indonesia. Although there are some barriers to implementation, with continued education and outreach to Volcano Observatories worldwide, greater use of the aviation color code system is achievable.

  13. Brief inhalation method to measure cerebral oxygen extraction fraction with PET: Accuracy determination under pathologic conditions

    SciTech Connect

    Altman, D.I.; Lich, L.L.; Powers, W.J. )

    1991-09-01

    The initial validation of the brief inhalation method to measure cerebral oxygen extraction fraction (OEF) with positron emission tomography (PET) was performed in non-human primates with predominantly normal cerebral oxygen metabolism (CMRO2). Sensitivity analysis by computer simulation, however, indicated that this method may be subject to increasing error as CMRO2 decreases. Accuracy of the method under pathologic conditions of reduced CMRO2 has not been determined. Since reduced CMRO2 values are observed frequently in newborn infants and in regions of ischemia and infarction in adults, we determined the accuracy of the brief inhalation method in non-human primates by comparing OEF measured with PET to OEF measured by arteriovenous oxygen difference (A-VO2) under pathologic conditions of reduced CMRO2 (0.27-2.68 ml 100g-1 min-1). A regression equation of OEF (PET) = 1.07 {times} OEF (A-VO2) + 0.017 (r = 0.99, n = 12) was obtained. The absolute error in oxygen extraction measured with PET was small (mean 0.03 {plus minus} 0.04, range -0.03 to 0.12) and was independent of cerebral blood flow, cerebral blood volume, CMRO2, or OEF. The percent error was higher (19 {plus minus} 37), particularly when OEF is below 0.15. These data indicate that the brief inhalation method can be used for measurement of cerebral oxygen extraction and cerebral oxygen metabolism under pathologic conditions of reduced cerebral oxygen metabolism, with these limitations borne in mind.

  14. Ultra Deep Wave Equation Imaging and Illumination

    SciTech Connect

    Alexander M. Popovici; Sergey Fomel; Paul Sava; Sean Crawley; Yining Li; Cristian Lupascu

    2006-09-30

    In this project we developed and tested a novel technology, designed to enhance seismic resolution and imaging of ultra-deep complex geologic structures by using state-of-the-art wave-equation depth migration and wave-equation velocity model building technology for deeper data penetration and recovery, steeper dip and ultra-deep structure imaging, accurate velocity estimation for imaging and pore pressure prediction and accurate illumination and amplitude processing for extending the AVO prediction window. Ultra-deep wave-equation imaging provides greater resolution and accuracy under complex geologic structures where energy multipathing occurs, than what can be accomplished today with standard imaging technology. The objective of the research effort was to examine the feasibility of imaging ultra-deep structures onshore and offshore, by using (1) wave-equation migration, (2) angle-gathers velocity model building, and (3) wave-equation illumination and amplitude compensation. The effort consisted of answering critical technical questions that determine the feasibility of the proposed methodology, testing the theory on synthetic data, and finally applying the technology for imaging ultra-deep real data. Some of the questions answered by this research addressed: (1) the handling of true amplitudes in the downward continuation and imaging algorithm and the preservation of the amplitude with offset or amplitude with angle information required for AVO studies, (2) the effect of several imaging conditions on amplitudes, (3) non-elastic attenuation and approaches for recovering the amplitude and frequency, (4) the effect of aperture and illumination on imaging steep dips and on discriminating the velocities in the ultra-deep structures. All these effects were incorporated in the final imaging step of a real data set acquired specifically to address ultra-deep imaging issues, with large offsets (12,500 m) and long recording time (20 s).

  15. The autophagic- lysosomal pathway determines the fate of glial cells under manganese- induced oxidative stress conditions.

    PubMed

    Gorojod, R M; Alaimo, A; Porte Alcon, S; Pomilio, C; Saravia, F; Kotler, M L

    2015-10-01

    Manganese (Mn) overexposure is frequently associated with the development of a neurodegenerative disorder known as Manganism. The Mn-mediated generation of reactive oxygen species (ROS) promotes cellular damage, finally leading to apoptotic cell death in rat astrocytoma C6 cells. In this scenario, the autophagic pathway could play an important role in preventing cytotoxicity. In the present study, we found that Mn induced an increase in the amount and total volume of acidic vesicular organelles (AVOs), a process usually related to the activation of the autophagic pathway. Particularly, the generation of enlarged AVOs was a ROS- dependent event. In this report we demonstrated for the first time that Mn induces autophagy in glial cells. This conclusion emerged from the results obtained employing a battery of autophagy markers: a) the increase in LC3-II expression levels, b) the formation of autophagic vesicles labeled with monodansylcadaverine (MDC) or LC3 and, c) the increase in Beclin 1/ Bcl-2 and Beclin 1/ Bcl-X(L) ratio. Autophagy inhibition employing 3-MA and mAtg5(K130R) resulted in decreased cell viability indicating that this event plays a protective role in Mn- induced cell death. In addition, mitophagy was demonstrated by an increase in LC3 and TOM-20 colocalization. On the other hand, we proposed the occurrence of lysosomal membrane permeabilization (LMP) based in the fact that cathepsins B and D activities are essential for cell death. Both cathepsin B inhibitor (Ca-074 Me) or cathepsin D inhibitor (Pepstatin A) completely prevented Mn- induced cytotoxicity. In addition, low dose of Bafilomycin A1 showed a similar effect, a finding that adds evidence about the lysosomal role in Mn cytotoxicity. Finally, in vivo experiments demonstrated that Mn induces injury and alters LC3 expression levels in rat striatal astrocytes. In summary, our results demonstrated that autophagy is activated to counteract the harmful effect caused by Mn. These data is valuable to

  16. EarthScope's Transportable Array in Alaska and Western Canada

    NASA Astrophysics Data System (ADS)

    Enders, M.; Miner, J.; Bierma, R. M.; Busby, R.

    2015-12-01

    EarthScope's Transportable Array (TA) in Alaska and Canada is an ongoing deployment of 261 high quality broadband seismographs. The Alaska TA is the continuation of the rolling TA/USArray deployment of 400 broadband seismographs in the lower 48 contiguous states and builds on the success of the TA project there. The TA in Alaska and Canada is operated by the IRIS Consortium on behalf of the National Science Foundation as part of the EarthScope program. By Sept 2015, it is anticipated that the TA network in Alaska and Canada will be operating 105 stations. During the summer 2015, TA field crews comprised of IRIS and HTSI station specialists, as well as representatives from our partner agencies the Alaska Earthquake Center and the Alaska Volcano Observatory and engineers from the UNAVCO Plate Boundary Observatory will have completed a total of 36 new station installations. Additionally, we will have completed upgrades at 9 existing Alaska Earthquake Center stations with borehole seismometers and the adoption of an additional 35 existing stations. As the array doubles in Alaska, IRIS continues to collaborate closely with other network operators, universities and research consortia in Alaska and Canada including the Alaska Earthquake Center (AEC), the Alaska Volcano Observatory (AVO), the UNAVCO Plate Boundary Observatory (PBO), the National Tsunami Warning Center (NTWC), Natural Resources Canada (NRCAN), Canadian Hazard Information Service (CHIS), the Yukon Geologic Survey (YGS), the Pacific Geoscience Center of the Geologic Survey, Yukon College and others. During FY14 and FY15 the TA has completed upgrade work at 20 Alaska Earthquake Center stations and 2 AVO stations, TA has co-located borehole seismometers at 5 existing PBO GPS stations to augment the EarthScope observatory. We present an overview of deployment plan and the status through 2015. The performance of new Alaska TA stations including improvements to existing stations is described.

  17. Lysosomes and unfolded protein response, determinants of differential resistance of melanoma cells to vinca alkaloids.

    PubMed

    Vincent, Laure-Anais; Attaoua, Chaker; Bellis, Michel; Rozkydalova, Lucie; Hadj-Kaddour, Kamel; Vian, Laurence; Cuq, Pierre

    2015-04-01

    On account of its strong ability to become chemoresistant after a primary response to drugs, malignant melanoma (MM) remains a therapeutic challenge. This study focuses on acquired resistance to vinca alkaloids (VAs) using VA-resistant MM cell lines (CAL1R-VCR, CAL1R-VDS, and CAL1R-VRB), established by long-term continuous exposure of parental CAL1-wt cells to vincristine (VCR), vindesine (VDS), or vinorelbine (VRB), respectively. Transcriptomic profiling using rma and rdam methods led to distinguish two cell groups: CAL1R-VCR and CAL1R-VDS, CAL1R-VRB, and CAL1-wt. mgsa of the specifically altered genes in the first group evidenced the GO terms 'lysosomal lumen' and 'vacuolar lumen' linked to underexpressed genes, and 'endoplasmic reticulum (ER) stress response' associated with overexpressed genes. A specific reduction of lysosomal enzymes, independent of acidic vacuole organelle (AVO) turnover, was observed (LTG probe) in CAL1R-VCR and CAL1R-VDS cells. It was associated with the specific lowering of cathepsin B and L, known to be involved in the lysosomal pathway of apoptosis. Confirming gene profiling, the same groups (CAL1R-VCR and CAL1R-VDS, CAL1-wt and CAL1R-VRB) could be distinguished regarding the VA-mediated changes on mean size areas and on acidic compartment volumes. These two parameters were reduced in CAL1R-VCR and CAL1R-VDS cells, suggesting a smaller AVO accumulation and thus a reduced sensitivity to lysosomal membrane permeabilization-mediated apoptosis. In addition, 'ER stress response' inhibition by tauroursodeoxycholic acid induced a higher VA sensitization of the first cell group. In conclusion, lysosomes and unfolded protein response could be key determinants of the differential resistance of MM to VAs. PMID:25601431

  18. Rock-physics-based carbonate pore type characterization and reservoir permeability heterogeneity evaluation, Upper San Andres reservoir, Permian Basin, west Texas

    NASA Astrophysics Data System (ADS)

    Dou, Qifeng; Sun, Yuefeng; Sullivan, Charlotte

    2011-05-01

    In addition to mineral composition and pore fluid, pore type variations play an important role in affecting the complexity of velocity-porosity relationship and permeability heterogeneity of carbonate reservoirs. Without consideration of pore type diversity, most rock physics models applicable to clastic rocks for explaining the rock acoustic properties and reservoir parameters relationship may not work well for carbonate reservoirs. A frame flexibility factor ( γ) defined in a new carbonate rock physics model can quantify the effect of pore structure changes on seismic wave velocity and permeability heterogeneity in carbonate reservoirs. Our study of an Upper San Andres carbonate reservoir, Permian Basin, shows that for core samples of given porosity, the lower the frame flexibility factor ( γ), the higher the sonic wave velocity. For the studied reservoir, samples with frame flexibility factor ( γ) < 3.85 represent either visible vuggy pore space in a dolopackstone or intercrystalline pore space in dolowackstone. On the other hand, samples with frame flexibility factor ( γ) > 3.85 indicate either dominant interparticle pore space in dolopackstone or microcrack pore space in dolowackstone or dolomudstone. Using the frame flexibility factor ( γ), different porosity-impedance and porosity-permeability trends can be classified with clear geologic interpretation such as pore type and rock texture variations to improve porosity and permeability prediction accuracy. New porosity-permeability relations with γ classification help delineate permeability heterogeneity in the Upper San Andres reservoir, and could be useful for other similar carbonate reservoir studies. In addition, results from analysis of amplitude variation with offset (AVO) and impedance modeling indicate that by combining rock physics model and pre-stack seismic inversion, simultaneous estimation of porosity and frame flexibility factor ( γ) is quite feasible because of the strong influence of

  19. Iterative Multiparameter Elastic Waveform Inversion Using Prestack Time Imaging and Kirchhoff approximation

    NASA Astrophysics Data System (ADS)

    Khaniani, Hassan

    This thesis proposes a "standard strategy" for iterative inversion of elastic properties from the seismic reflection data. The term "standard" refers to the current hands-on commercial techniques that are used for the seismic imaging and inverse problem. The method is established to reduce the computation time associated with elastic Full Waveform Inversion (FWI) methods. It makes use of AVO analysis, prestack time migration and corresponding forward modeling in an iterative scheme. The main objective is to describe the iterative inversion procedure used in seismic reflection data using simplified mathematical expression and their numerical applications. The frame work of the inversion is similar to (FWI) method but with less computational costs. The reduction of computational costs depends on the data conditioning (with or without multiple data), the level of the complexity of geological model and acquisition condition such as Signal to Noise Ratio (SNR). Many processing methods consider multiple events as noise and remove it from the data. This is the motivation for reducing the computational cost associated with Finite Difference Time Domain (FDTD) forward modeling and Reverse Time Migration (RTM)-based techniques. Therefore, a one-way solution of the wave equation for inversion is implemented. While less computationally intensive depth imaging methods are available by iterative coupling of ray theory and the Born approximation, it is shown that we can further reduce the cost of inversion by dropping the cost of ray tracing for traveltime estimation in a way similar to standard Prestack Time Migration (PSTM) and the corresponding forward modeling. This requires the model to have smooth lateral variations in elastic properties, so that the traveltime of the scatterpoints can be approximated by a Double Square Root (DSR) equation. To represent a more realistic and stable solution of the inverse problem, while considering the phase of supercritical angles, the

  20. Meltwater Origin of the 2005 Mount Steller Landslide Confirmed by Analysis of Global Fiducials Program Imagery

    NASA Astrophysics Data System (ADS)

    Molnia, B. F.; Angeli, K.

    2012-12-01

    Alaska's Mt. Steller, a 3,236 m Chugach Mountains peak, is one of the target areas of the Bering Glacier Global Fiducials Program (GFP) site. On September 14, 2005, a large mass of rock, glacier ice, and snow, with a volume of ~50 million cubic meters, fell from just below Mt. Steller's south-facing summit and landed on the surface of a tributary to Bering Glacier, nearly 2,500 m below. The slide, which extended ~8 km down-glacier, was actually an ice-rock avalanche. The impact generated a seismic signal recorded with a magnitude of up to 5.2. Oblique aerial photography of the mountain, the head scarp, and the slide mass was collected for the U.S. Geological Survey's Alaska Volcano Observatory (AVO) on September 15, 2005. The photography delineated the morphology of the failed south-facing slope of the mountain and showed details of the sheared, near-summit hanging glacier and snow mass. Based on the photography, the AVO calculated the slide volume and length. Several weeks later, the AVO provided the first author with digital copies of the September 15 photography. These images were enhanced and examined in order to determine properties of the slide and to evaluate if the cause of the event could be determined. A number of features observed led to the conclusion that meltwater was probably responsible for destabilizing the glacier ice-bedrock contact and triggering the landslide. Specifically, a 10-15 m diameter englacial stream channel was seen in the truncated glacier ice that comprised the east wall of the landslide scarp and a water-polished channel opening was noted on the west wall scarp. Additionally, several depressions were noted that might have temporarily stored water. To confirm these observations, new cloud-free GFP imagery was obtained on October 24 and 28, 2005. Analysis of both sets of imagery documented that: (1) more than a month after the event, meltwater was exiting the east wall scarp channel and flowing down the face of the mountain; (2) the

  1. Detection and Appraisal of Gas Hydrates: Indian Scenario

    NASA Astrophysics Data System (ADS)

    Sain, K.

    2009-04-01

    Gas hydrates, found in shallow sediments of permafrost and outer continental margins, are crystalline form of methane and water. The carbon within global gas hydrates is estimated two times the carbon contained in world-wide fossil fuels. It is also predicted that 15% recovery of gas hydrates can meet the global energy requirement for the next 200 years. Several parameters like bathymetry, seafloor temperature, sediment thickness, rate of sedimentation and total organic carbon content indicate very good prospect of gas hydrates in the vast offshore regions of India. Methane stored in the form of gas hydrates within the Indian exclusive economic zone is estimated to be few hundred times the country's conventional gas reserve. India produces less than one-third of her oil requirement and gas hydrates provide great hopes as a viable source of energy in the 21st century. Thus identification and quantitative assessment of gas hydrates are very important. By scrutiny and reanalysis of available surface seismic data, signatures of gas hydrates have been found out in the Kerala-Konkan and Saurashtra basins in the western margin, and Krishna-Godavari, Mahanadi and Andaman regions in the eastern margin of India by mapping the bottom simulating reflector or BSR based on its characteristic features. In fact, the coring and drilling in 2006 by the Indian National Gas Hydrate Program have established the ground truth in the eastern margin. It has become all the more important now to identify further prospective regions with or without BSR; demarcate the lateral/areal extent of gas hydrate-bearing sediments and evaluate their resource potential in both margins of India. We have developed various approaches based on seismic traveltime tomography; waveform inversion; amplitude versus offset (AVO) modeling; AVO attributes; seismic attributes and rock physics modeling for the detection, delineation and quantification of gas-hydrates. The blanking, reflection strength, instantaneous

  2. Missing Black Holes Driven Out

    NASA Astrophysics Data System (ADS)

    2004-05-01

    difficult task to find them. Because of the obscuring effect of dust, they cannot be found through standard (i.e. in the visible) methods of quasar selection. The only way to hope to drive them out of their bushes is to detect them through their hard X-rays which are able to penetrate through the torus. But this requires that astronomers can analyse and cross-correlate in a very efficient way the observations from several space- and ground-based observatories, which together span the entire range of wavelengths. Type-2 quasars can indeed be identified as the only objects appearing very red and at the same time emitting strongly in X-rays. Virtual Observatories ESO PR Photo 17/04 ESO PR Photo 17/04 [Preview - JPEG: 400 x 415 pix - 57k] [Normal - JPEG: 800 x 829 pix - 764k] [FullRes - JPEG: 1702 x 1764 pix - 2.0M] Caption: ESO PR Photo 17/04 shows the Astrophysical Virtual Observatory (AVO) visualisation interface; it interface is based on Centre de Donneés Astronomiques de Strasbourg's Aladin. AVO devises new methods for accessing and describing data in a way that allows images, spectra and information from different sources to work together seamlessly. This is where Virtual Observatories can play a decisive role. Major breakthroughs in telescope, detector, and computer technology now allow astronomical surveys to produce massive amounts of images, spectra, and catalogues. These datasets cover the sky at all wavelengths from gamma- and X-rays, optical, infrared, to radio waves. Virtual Observatories are an international, community-based initiative, to allow global electronic access to available astronomical data in a seamless and transparent way. The Astrophysical Virtual Observatory project (AVO) ([1]) is the effort in Virtual Observatories of the European astronomical community. Funded jointly by the European Commission and six participating European organisations, it is led by the European Southern Observatory (ESO). The AVO science team headed by Paolo Padovani (ST

  3. New Coastal Tsunami Gauges: Application at Augustine Volcano, Cook Inlet, Alaska

    NASA Astrophysics Data System (ADS)

    Burgy, M.; Bolton, D. K.

    2006-12-01

    Recent eruptive activity at Augustine Volcano and its associated tsunami threat to lower Cook Inlet pointed out the need for a quickly deployable tsunami detector which could be installed on Augustine Island's coast. The detector's purpose would be to verify tsunami generation by direct observation of the wave at the source to support tsunami warning decisions along populated coastlines. To fill this need the Tsunami Mobile Alert Real-Time (TSMART) system was developed at NOAA's West Coast/Alaska Tsunami Warning Center with support from the University of Alaska Tsunami Warning and Environmental Observatory for Alaska program (TWEAK) and the Alaska Volcano Observatory (AVO). The TSMART system consists of a pressure sensor installed as near as possible to the low tide line. The sensor is enclosed in a water-tight hypalon bag filled with propylene-glycol to prevent silt damage to the sensor and freezing. The bag is enclosed in a perforated, strong plastic pipe about 16 inches long and 8 inches in diameter enclosed at both ends for protection. The sensor is cabled to a data logger/radio/power station up to 300 feet distant. Data are transmitted to a base station and made available to the warning center in real-time through the internet. This data telemetry system can be incorporated within existing AVO and Plate Boundary Observatory networks which makes it ideal for volcano-tsunami monitoring. A TSMART network can be utilized anywhere in the world within 120 miles of an internet connection. At Augustine, two test stations were installed on the east side of the island in August 2006. The sensors were located very near the low tide limit and covered with rock, and the cable was buried to the data logger station which was located well above high tide mark. Data logger, radio, battery and other electronics are housed in an enclosure mounted to a pole which also supports an antenna and solar panel. Radio signal is transmitted to a repeater station higher up on the island

  4. Tephra Studies by the Alaska Volcano Observatory: Present and Future Research

    NASA Astrophysics Data System (ADS)

    Waythomas, C. F.; Wallace, K. L.

    2004-12-01

    Tephra from Aleutian arc volcanoes constitutes an important volcanic hazard for Alaska, western Canada, and some parts of the conterminous U.S. where even small amounts of airborne ash may have dire consequences for jet aircraft traversing North Pacific and western U.S. air routes. Motivated by the need to address volcanic ash hazards on a regional scale, we have initiated a program of tephra studies within the auspices of the Alaska Volcano Observatory (AVO) of the U.S. Geological Survey. A concentrated focus on tephra problems and a new laboratory facility within AVO will help facilitate studies of Quaternary age tephra at Alaskan volcanoes by providing a regional center for laboratory analyses of volcanic ash and standardized web-based reporting and archiving of tephra data. In its first year of operation, the laboratory has been engaged in research at Veniaminof, Mt. Spurr, and Augustine volcanoes, has sponsored research on Holocene tephra deposits of upper Cook Inlet, and has initiated analytical studies of tephra deposits on Adak and Kanaga Islands in the western Aleutians. The objective of these studies is to develop multiparameter techniques for characterization and correlation of tephra deposits, establish radiocarbon-controlled tephrostratigraphic frameworks, and to evaluate the magnitude and frequency of tephra-producing eruptions. In the upper Cook Inlet region of Alaska, we and our colleagues have begun developing a comprehensive record of ash fall by systematically selecting and coring shallow lakes and evaluating the tephra preserved in the lacustrine sediment. Sediment cores from these lakes contain numerous tephra deposits of Holocene age in datable context that can be correlated with proximal tephra deposits on the flanks of their source volcanoes. By combining tephra data from lacustrine deposits and natural exposures we hope to develop a robust geologic catalog of tephra deposits that will enable long-distance correlation of tephras, provide

  5. Autophagy inhibition enhances RAD001-induced cytotoxicity in human bladder cancer cells

    PubMed Central

    Lin, Ji-Fan; Lin, Yi-Chia; Yang, Shan-Che; Tsai, Te-Fu; Chen, Hung-En; Chou, Kuang-Yu; Hwang, Thomas I-Sheng

    2016-01-01

    Background Mammalian target of rapamycin (mTOR), involved in PI3K/AKT/mTOR pathway, is known to play a central role in regulating the growth of cancer cells. The PI3K/AKT/mTOR pathway enhances tumor survival and proliferation through suppressing autophagy, which sustains energy homeostasis by collecting and recycling cellular components under stress conditions. Conversely, inhibitors of the mTOR pathway such as RAD001 induce autophagy, leading to promotion of tumor survival and limited antitumor efficacy. We thus hypothesized that the use of autophagy inhibitor in combination with mTOR inhibition improves the cytotoxicity of mTOR inhibitors in bladder cancer. Materials and methods The cytotoxicity of RT4, 5637, HT1376, and T24 human bladder cancer cells treated with RAD001 alone or combined with autophagy inhibitors (3-methyladenine (3-MA), bafilomycin A1 (Baf A1), chloroquine, or hydroxychloroquine) was assessed using the WST-8 cell viability kit. The autophagy status in cells was analyzed by the detection of microtubule-associated light chain 3 form II (LC3-II), using immunofluorescent staining and Western blot. Acidic vesicular organelle (AVO) formation in treated cells was determined by acridine orange vital staining. Inhibition of mTOR pathway by RAD001 was monitored by using a homemade quantitative polymerase chain reaction gene array, while phospho-mTOR was detected using Western blot. Induced apoptosis was determined by measurement of caspase 3/7 activity and DNA fragmentation in cells after treatment. Results Advanced bladder cancer cells (5637, HT1376, and T24) were more resistant to RAD001 than RT4. Autophagy flux detected by the expression of LC3-II showed RAD001-induced autophagy. AVO formation was detected in cells treated with RAD001 and was inhibited by the addition of 3-MA or Baf A1. Cotreatment of RAD001 with autophagy inhibitors further reduced cell viability and induced apoptosis in bladder cancer cells. Conclusion Our results indicate that

  6. Completely <001> oriented anatase TiO2 nanoarrays: topotactic growth and orientation-related efficient photocatalysis

    NASA Astrophysics Data System (ADS)

    Yang, Jingling; Wu, Qili; He, Shiman; Yan, Jing; Shi, Jianying; Chen, Jian; Wu, Mingmei; Yang, Xianfeng

    2015-08-01

    A TiO2 film has been facilely grown on a Ti foil via a general and simple acid vapor oxidation (AVO) strategy. Based on detailed characterization by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), we found that the TiO2 film was composed of anatase nanoarrays highly oriented along their <001> direction, resulting in a large exposed {001} top surface on the film. The growth mechanism based on a topotactic transformation was proposed according to a careful study of time-dependent experimental results. Resulting from the evaluation of photocatalytic performance compared with a commercial TiO2 photocatalyst (Degussa P25), the as-prepared oriented anatase TiO2 film showed higher efficiency for degradation of atrazine and acid orange II (AOII). The performance of photocatalysis is highly relevant to the preferential orientation. The efficient photocatalysis could be attributed to the highly reactive {001} facets on the anatase nanoarrays with super-hydrophilicity.A TiO2 film has been facilely grown on a Ti foil via a general and simple acid vapor oxidation (AVO) strategy. Based on detailed characterization by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), we found that the TiO2 film was composed of anatase nanoarrays highly oriented along their <001> direction, resulting in a large exposed {001} top surface on the film. The growth mechanism based on a topotactic transformation was proposed according to a careful study of time-dependent experimental results. Resulting from the evaluation of photocatalytic performance compared with a commercial TiO2 photocatalyst (Degussa P25), the as-prepared oriented anatase TiO2 film showed higher efficiency for degradation of atrazine and acid orange II (AOII). The performance of photocatalysis is highly relevant to the preferential orientation. The efficient photocatalysis could be attributed to the highly

  7. Intermediate-Term Declines in Seismicity at Mt. Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002 Mw 7.9 Denali Fault Earthquake

    NASA Astrophysics Data System (ADS)

    Sanchez, J. J.; McNutt, S. R.

    2003-12-01

    On November 3, 2002 a Mw 7.9 earthquake ruptured segments of the Denali Fault and adjacent faults in interior Alaska providing a unique opportunity to look for intermediate-term (days to weeks) responses of Alaskan volcanoes to shaking from a large regional earthquake. The Alaska Volcano Observatory (AVO) monitors 24 volcanoes with seismograph networks. We examined one station per volcano, generally the closest to the vent (typically within 5 km) unless noise, or other factors made the data unusable. Data were digitally filtered between 0.8 and 5 Hz to enhance the signal-to-noise ratio. Data for the period four weeks before to four weeks after the Mw 7.9 earthquake were then plotted at a standard scale used for AVO routine monitoring. Mt. Veniaminof volcano, which has had recent mild eruptions and a rate of ten earthquakes per day on station VNNF, suffered a drop in seismicity by a factor of two after the earthquake; this lasted for 15 days. Wrangell, the closest volcano to the epicenter, had a background rate of about 16 earthquakes per day. Data from station WANC could not be measured for 3 days after the Mw 7.9 earthquake because the large number and size of aftershocks impeded identification of local earthquakes. For the following 30 days, however, its seismicity rate dropped by a factor of two. Seismicity then remained low for an additional 4 months at Wrangell, whereas that at Veniaminof returned to normal within weeks. The seismicity at both Mt. Veniaminof and Mt. Wrangell is dominated by low-frequency volcanic events. The detection thresholds for both seismograph networks are low and stations VNNF and WANC operated normally during the time of our study, thus we infer that the changes in seismicity may be related to the earthquake. It is known that Wrangell increased its heat output after the Mw 9.2 Alaska earthquake of 1964 and again after the Ms 7.1 St.Elias earthquake of 1979. The other volcanoes showed no changes in seismicity that can be attributable to

  8. Evaluation of the seismic reflection method as a monitoring tool during primary and enhanced coalbed methane production

    NASA Astrophysics Data System (ADS)

    Lespinasse Fung, Diane Jael

    In this thesis I present an evaluation of the seismic reflection method as a monitoring tool during coalbed methane (CBM) production and enhanced coalbed methane (ECBM) production by CO2 injection. This evaluation is based on a workflow previously developed for monitoring CO2 storage in the Big George coalbeds in the Powder River Basin. I study the changes in seismic and the AVO response associated with coalbeds during primary production using a data set from the Mannville coals, which represent one of the most important CBM resources in the Province of Alberta. Using published data, I perform a single well flow simulation to make an assessment of its production forecast in a 10 year period. The flow simulation provides information on methane saturation and reservoir pressure during production, while the changes in porosity and permeability due to depletion are estimated according to the Palmer and Mansoori permeability model. Using well log data of the Corbett Field and the results of the flow simulation, I complete a Gassmann fluid substitution to replace brine by a mixture of brine and methane in the pore space and estimate the variations in Vp, Vs and density due to changes in fluid saturation. I evaluate offset dependent synthetic seismograms before and after fluid substitution, and I use different coalbed thicknesses to establish resolution limits. To observe significant changes in the character and phase of the wavelet due to the replacement of brine by methane I find that coalbed thickness must be at least 10 m, also in terms of AVO I observe that there is a decrease in amplitude with offset caused by the presence of methane in the pore space. Using the same methodology and production data from the Fruitland Coals Fairway in the North of the San Juan Basin U.S.A, which is considered the most productive CBM reservoir in the world, I evaluate Elastic Impedance (EI) and Elastic Impedance Coefficient (EC) response during ECBM by CO2 injection. In this case, I

  9. Augustine Volcano, Cook Inlet, Alaska (January 31, 2006)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Since last spring, the U.S. Geological Survey's Alaska Volcano Observatory (AVO) has detected increasing volcanic unrest at Augustine Volcano in Cook Inlet, Alaska near Anchorage. Based on all available monitoring data, AVO regards that an eruption similar to 1976 and 1986 is the most probable outcome. During January, activity has been episodic, and characterized by emission of steam and ash plumes, rising to altitudes in excess of 9,000 m (30,000 ft), and posing hazards to aircraft in the vicinity. In the last week, volcanic flows have been seen on the volcano's flanks. An ASTER thermal image was acquired at night at 22:50 AST on January 31, 2006, during an eruptive phase of Augustine. The image shows three volcanic flows down the north flank of Augustine as white (hot) areas. The eruption plume spreads out to the east in a cone shape: it appears dark blue over the summit because it is cold and water ice dominates the composition; further downwind a change to orange color indicates that the plume is thinning and the signal is dominated by the presence of ash.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at

  10. Variation of shear and compressional wave modulus upon saturation for pure pre-compacted sands

    NASA Astrophysics Data System (ADS)

    Bhuiyan, M. H.; Holt, R. M.

    2016-04-01

    Gassmann's fluid substitution theory is commonly used to predict seismic velocity change upon change in saturation, and is hence essential for 4D seismic and AVO studies. This paper addresses the basics assumptions of the Gassmann theory, in order to see how well they are fulfilled in controlled laboratory experiments. Our focus is to investigate the sensitivity of shear modulus to fluid saturation, and the predictability of Gassmann's fluid substitution theory for P-wave modulus. Ultrasonic P- and S-wave velocities in dry and saturated (3.5wt% NaCl) unconsolidated clean sands (Ottawa and Columbia) were measured in an oedometer test system (uniaxial strain conditions) over a range of 0.5 MPa to 10 MPa external vertical stress. This study shows shear modulus hardening upon brine saturation, which is consistent with previous data found in the literature. Analysis of the data shows that most of the hardening of the ultrasonic shear modulus may be explained by Biot dispersion. Isotropic Gassmann's fluid substitution is found to underestimate the P-wave modulus upon fluid saturation. However, adding the Biot dispersion effect improves the prediction. More work is required to obtain good measurements of parameters influencing dispersion, such as tortuosity, which is very ambiguous and challenging to measure accurately.

  11. Numerical investigations on mapping permeability heterogeneity in coal seam gas reservoirs using seismo-electric methods

    NASA Astrophysics Data System (ADS)

    Gross, L.; Shaw, S.

    2016-04-01

    Mapping the horizontal distribution of permeability is a key problem for the coal seam gas industry. Poststack seismic data with anisotropy attributes provide estimates for fracture density and orientation which are then interpreted in terms of permeability. This approach delivers an indirect measure of permeability and can fail if other sources of anisotropy (for instance stress) come into play. Seismo-electric methods, based on recording the electric signal from pore fluid movements stimulated through a seismic wave, measure permeability directly. In this paper we use numerical simulations to demonstrate that the seismo-electric method is potentially suitable to map the horizontal distribution of permeability changes across coal seams. We propose the use of an amplitude to offset (AVO) analysis of the electrical signal in combination with poststack seismic data collected during the exploration phase. Recording of electrical signals from a simple seismic source can be closer to production planning and operations. The numerical model is based on a sonic wave propagation model under the low frequency, saturated media assumption and uses a coupled high order spectral element and low order finite element solver. We investigate the impact of seam thickness, coal seam layering, layering in the overburden and horizontal heterogeneity of permeability.

  12. C5 induces different cell death pathways in promastigotes of Leishmania amazonensis.

    PubMed

    Mendes, Edevi Arbonelli; Desoti, Vânia Cristina; Silva, Sueli de Oliveira; Ueda-Nakamura, Tânia; Dias Filho, Benedito Prado; Yamada-Ogatta, Sueli Fumie; Sarragiotto, Maria Helena; Nakamura, Celso Vataru

    2016-08-25

    Leishmaniasis is a neglected infection that is caused by Leishmania protozoa, affecting millions of people worldwide, mainly in tropical and subtropical regions. This disease has different clinical forms: cutaneous, mucocutaneous, and visceral. The drugs that are currently available for the treatment of this infection have limitations, such as high toxicity, long-term treatment, and leads to drug-resistant strains. Numerous studies, in various experimental models, have sought to develop more effective and less toxic chemotherapeutic agents against leishmaniasis. In the present study, we evaluated the mechanism of cell death that is induced by n-benzyl 1-(4-methoxy)phenyl-9H-β-carboline-3-carboxamide (C5) against Leishmania amazonensis. C5 increased reactive oxygen species production, depolarization of the mitochondrial membrane, DNA fragmentation, decrease of cell volume, lipoperoxidation, the accumulation of lipid bodies, and acidic vesicular organelles (AVOs) and caused the intense formation of autophagic compartments in L. amazonensis promastigotes. The results indicate that C5 causes L. amazonensis death through different pathways. PMID:27317947

  13. Combination of retinyl palmitate and UV-filters: phototoxic risk assessment based on photostability and in vitro and in vivo phototoxicity assays.

    PubMed

    Benevenuto, Carolina Gomes; Guerra, Lucas Offenbecker; Gaspar, Lorena Rigo

    2015-02-20

    This study aimed to assess the phototoxic potential of combined UV-filters and retinyl palmitate (RP) in the presence or not of bemotrizinol (BMTZ), employing photostability and in vitro and in vivo phototoxicity assays. The formulations tested contained octocrylene (OCT), octyl methoxycinnamate (OMC), benzophenone-3 (BZP-3) and RP (photostable) or octocrylene (OCT), octyl methoxycinnamate (OMC), avobenzone (AVO) and RP (less photostable). Both formulations were supplemented with bemotrizinol. Photostability was evaluated by exposing, or not, formulations spread on a glass plate to UVA/UVB irradiation. The resulting products were quantified by HPLC analysis. In vitro phototoxicity of UV-filters and combinations were evaluated using 3T3 viable monolayer fibroblast cultures submitted, or not, to irradiation according to OECD TG 432. In vivo photoallergy and photoxicity were assessed by clinical studies (photopatch test). Photostability assays showed that UV-filter bemotrizinol was a better photostabilizer for RP/benzophenone-3 than for RP/avobenzone. The in vitro phototoxicity of the combination RP/avobenzone was reduced by bemotrizinol. Clinical studies did not indicate phototoxic or photoallergenic potentials in all formulations tested. It is concluded that the 3T3 NRU phototoxicity test may be considered a supplementary assay in formulation developments, since it can detect chemically unstable and potentially phototoxic combinations. However, extrapolation of in vitro positive results to human photopatch tests may be performed only to a limited extent. PMID:25533240

  14. Autophagic Cell Death by Poncirus trifoliata Rafin., a Traditional Oriental Medicine, in Human Oral Cancer HSC-4 Cells

    PubMed Central

    Han, Hye-Yeon; Park, Bong-Soo; Lee, Guem San; Jeong, Seung-Hwa; Kim, Hyungwoo; Ryu, Mi Heon

    2015-01-01

    Poncirus trifoliata Rafin. has long been used as anti-inflammatory and antiallergic agent to treat gastrointestinal disorders and pulmonary diseases such as indigestion, constipation, chest fullness, chest pain, bronchitis, and sputum in Korea. P. trifoliata extract has recently been reported to possess anticancer properties; however, its mechanisms of action remain unclear. In this study, its antiproliferative effects and possible mechanisms were investigated in HSC-4 cells. The methanol extract of P. trifoliata (MEPT) significantly decreased the proliferation of HSC-4 cells (inhibitory concentration (IC)50 = 142.7 μg/mL) in a dose-dependent manner. While there were no significant changes observed upon cell cycle analysis and ANNEXIN V and 7-AAD double staining in the MEPT-treated groups, the intensity of acidic vesicular organelle (AVO) staining and microtubule-associated protein 1 light chain (LC) 3-II protein expression increased in response to MEPT treatment. Furthermore, 3-methyladenine (3-MA, autophagy inhibitor) effectively blocked the MEPT-induced cytotoxicity of HSC-4 cells and triggered the activation of p38 and extracellular signal-regulated kinases (ERK) proteins. Taken together, our results indicate that MEPT is a potent autophagy agonist in oral cancer cells with antitumor therapeutic potential that acts through the mitogen-activated protein kinase (MAPK) pathway. PMID:26221173

  15. Rock Physics of Geologic Carbon Sequestration/Storage

    SciTech Connect

    Dvorkin, Jack; Mavko, Gary

    2013-05-31

    This report covers the results of developing the rock physics theory of the effects of CO{sub 2} injection and storage in a host reservoir on the rock's elastic properties and the resulting seismic signatures (reflections) observed during sequestration and storage. Specific topics addressed are: (a) how the elastic properties and attenuation vary versus CO{sub 2} saturation in the reservoir during injection and subsequent distribution of CO{sub 2} in the reservoir; (b) what are the combined effects of saturation and pore pressure on the elastic properties; and (c) what are the combined effects of saturation and rock fabric alteration on the elastic properties. The main new results are (a) development and application of the capillary pressure equilibrium theory to forecasting the elastic properties as a function of CO{sub 2} saturation; (b) a new method of applying this theory to well data; and (c) combining this theory with other effects of CO{sub 2} injection on the rock frame, including the effects of pore pressure and rock fabric alteration. An important result is translating these elastic changes into synthetic seismic responses, specifically, the amplitude-versus-offset (AVO) response depending on saturation as well as reservoir and seal type. As planned, three graduate students participated in this work and, as a result, received scientific and technical training required should they choose to work in the area of monitoring and quantifying CO{sub 2} sequestration.

  16. Full-waveform modeling and inversion of physical model data

    NASA Astrophysics Data System (ADS)

    Cai, Jian; Zhang, Jie

    2016-08-01

    Because full elastic waveform inversion requires considerable computation time for forward modeling and inversion, acoustic waveform inversion is often applied to marine data for reducing the computational time. To understand the validity of the acoustic approximation, we study data collected from an ultrasonic laboratory with a known physical model by applying elastic and acoustic waveform modeling and acoustic waveform inversion. This study enables us to evaluate waveform differences quantitatively between synthetics and real data from the same physical model and to understand the effects of different objective functions in addressing the waveform differences for full-waveform inversion. Because the materials used in the physical experiment are viscoelastic, we find that both elastic and acoustic synthetics differ substantially from the physical data over offset in true amplitude. If attenuation is taken into consideration, the amplitude versus offset (AVO) of viscoelastic synthetics more closely approximates the physical data. To mitigate the effect of amplitude differences, we apply trace normalization to both synthetics and physical data in acoustic full-waveform inversion. The objective function is equivalent to minimizing the phase differences with indirect contributions from the amplitudes. We observe that trace normalization helps to stabilize the inversion and obtain more accurate model solutions for both synthetics and physical data.

  17. Reproducibility of cardioventilatory measurements using a respiratory mass spectrometer.

    PubMed

    Narang, Indra; Rosenthal, Mark; Bush, Andrew

    2007-08-01

    The aim of this study was to assess the within subject reproducibility of cardioventilatory measurements and the maximum permitted 'normal' variability over time at rest and exercise using the respiratory mass spectrometer (RMS). Ten subjects underwent an incremental exercise test on three separate occasions utilising rebreathing (RB) and helium dilution mixed expired gas analysis (HME) functions of the RMS. Measurements included heart rate (HR), oxygen consumption (V(O2)), carbon dioxide excretion (V(VO2)), effective pulmonary blood flow (Q(eff)), stroke volume (SV), arteriovenous oxygen content difference (AVO), transfer factor (Dl(CO)), functional residual capacity (FRC), minute ventilation (VE), tidal volume (VT) and respiratory quotient (RQ). The coefficients of variation for each variable for the 10 subjects were calculated. At rest, the 90th centile variability for measured cardiopulmonary variables (RB only) was <35%. During exercise, the 90th centile for variability for measured cardiopulmonary variables for HME and RB were < or =20 and <40%, respectively. These measurements in healthy adults should inform sample size in research studies. PMID:17188945

  18. Automatic picking and attribute mapping for a quick evaluation of the potential of turbiditic sands and stratigraphic traps in frontier areas. An example from the deep offshore of the Niger Delta

    SciTech Connect

    Montagnier, P.; Rossi, T.; Clergeat, B.; Dall`astam, W.F.

    1996-12-31

    Most interpretation teams involved in the exploration of Nigeria`s deep offshore have been faced with a major challenge: (1) how to scan through a large volume of 3D data in a drastically short time frame... (2) with the captive of understanding the depositional pattern of slope fan and basin floor fan turbidites to identify mostly stratigraphic traps... (3) in an environment almost devoid of reference wells and calibration. A traditional approach was likely to miss both the deadlines and the sensitivity required for the sedimentological aspects of the study. Elfs answer was to rely extensively on the advanced functionalities of the SISMAGE (TM) workstation, in order to quickly generate time and seismic attribute maps which could then be interpreted in terms of structure and sedimentology. Two critical aspects were particularly well handled by the workstation: (1) the reliability of the extrapolation process from a loose grid of manually picked lines, and (2) the generation of seismic attribute maps relative not only to surfaces (e.g. sequence boundaries), but also to whole intervals through statistical calculation. In a second stage, the interpreters were able to focus on the most prospective areas and to move on to prospect generation, with the help of AVO studies. This approach is illustrated through an example from the deep offshore of the Niger delta.

  19. Automatic picking and attribute mapping for a quick evaluation of the potential of turbiditic sands and stratigraphic traps in frontier areas. An example from the deep offshore of the Niger Delta

    SciTech Connect

    Montagnier, P.; Rossi, T. ); Clergeat, B.; Dall'astam, W.F. )

    1996-01-01

    Most interpretation teams involved in the exploration of Nigeria's deep offshore have been faced with a major challenge: (1) how to scan through a large volume of 3D data in a drastically short time frame... (2) with the captive of understanding the depositional pattern of slope fan and basin floor fan turbidites to identify mostly stratigraphic traps... (3) in an environment almost devoid of reference wells and calibration. A traditional approach was likely to miss both the deadlines and the sensitivity required for the sedimentological aspects of the study. Elfs answer was to rely extensively on the advanced functionalities of the SISMAGE (TM) workstation, in order to quickly generate time and seismic attribute maps which could then be interpreted in terms of structure and sedimentology. Two critical aspects were particularly well handled by the workstation: (1) the reliability of the extrapolation process from a loose grid of manually picked lines, and (2) the generation of seismic attribute maps relative not only to surfaces (e.g. sequence boundaries), but also to whole intervals through statistical calculation. In a second stage, the interpreters were able to focus on the most prospective areas and to move on to prospect generation, with the help of AVO studies. This approach is illustrated through an example from the deep offshore of the Niger delta.

  20. The Simple Spectral Access protocol

    NASA Astrophysics Data System (ADS)

    Dolensky, Markus; Tody, Doug

    2004-09-01

    The goal of the Simple Spectral Access (SSA) specification is to define a uniform interface to spectral data including spectral energy distributions (SEDs), 1D spectra, and time series data. In contrast to 2D images, spectra are stored in a wide variety of formats and there is no widely used standard in astronomy for representing spectral data, hence part of the challenge of specifying SSA was defining a general spectrophotometric data model as well as definitions of standard serializations in a variety of data formats including XML and FITS. Access is provided to both atlas (pre-computed) data and to virtual data which is computed on demand. The term simple in Simple Spectrum Access refers to the design goal of simplicity in both implementing spectral data services and in retrieving spectroscopic data from distributed data collections. SSA is a product of the data access layer (DAL) working group of the International Virtual Observatory Alliance (IVOA). The requirements were derived from a survey among spectral data providers and data consumers and were further refined in a broad discussion in meetings and electronic forums as well as by prototyping efforts within the European Astrophysical Virtual Observatory (AVO) and the US National Virtual Observatory (NVO).

  1. Cardiovascular responses to a hot tub bath.

    PubMed

    Boone, T; Westendorf, T; Ayres, P

    1999-06-01

    This study was conducted to determine the cardiovascular effects of 15 minutes of hot tub immersion at 39 degrees C. Five college-age subjects (4 males and 1 female) volunteered to participate in this study. Assessments were made while sitting first in a chair for 5 minutes and then in the hot tub for 15 minutes. Oxygen consumption (VO2) and cardiac output (Q) measurements were made using a Medical Graphics CPX/D metabolic analyzer. Cardiac output was determined at minute 15 using the indirect CO2 rebreathing procedure. The data were analyzed using the analysis of variance with repeated measures, which indicated that at minute 15, heart rate (HR) and Q were increased, which increased VO2. The increase in Q was due to the heart rate (HR) response and the decrease in systemic vascular resistance (SVR). Mean arterial pressure (MAP) and systolic blood pressure (SBP) were decreased while double product (DP) was increased. There were no changes in stroke volume (SV) or arteriovenous oxygen difference (a-vO2 diff). These findings indicate that the HR and Q responses are necessary to the increase in metabolism (VO2). Hot tube use within these time and temperature constraints should reduce concern over hot tub safety in college-age subjects. PMID:10381255

  2. Integrated seismic study of naturally fractured tight gas reservoirs. Technical progress report, April 1, 1993--June 31, 1993

    SciTech Connect

    Mavko, G.; Nur, A.

    1993-07-26

    This was the seventh quarter of the contract. During this quarter we (1) continued the large task of processing the seismic data, (2) collected additional geological information to aid in the interpretation, (3) tied the well log data to the seismic via generation of synthetic seismograms, (4) began integrating regional structural information and fracture trends with our observations of structure in the study area, (5) began constructing a velocity model for time-to-depth conversion and subsequent AVO and raytrace modeling experiments, and (6) completed formulation of some theoretical tools for relating fracture density to observed elastic anisotropy. The study area is located at the southern end of the Powder River Basin in Converse County in east-central Wyoming. It is a low permeability fractured site, with both gas and oil present. Reservoirs are highly compartmentalized due to the low permeabilities, and fractures provide the only practical drainage paths for production. The two formations of interest are: The Niobrara: a fractured shale and limey shale to chalk, which is a reservoir rock, but also its own source rock. The Frontier: a tight sandstone lying directly below the Niobrara, brought into contact with it by an unconformity. A basemap is presented with the seismic lines being analyzed for this project plus locations of 13 wells that we are using to supplement the analysis. The arrows point to two wells for which we have constructed synthetic seismograms.

  3. Inversion-based directional deconvolution to remove the effect of a geophone array on seismic signal

    NASA Astrophysics Data System (ADS)

    Li, Guofa; Zheng, Hao; Wang, Jingjing; Huang, Wei

    2016-07-01

    The geophone array, as a directivity filter, has been widely used in seismic data acquisition for suppressing noises and alias-free sampling, and its negative effects have long been recognized by analyzing its response to harmonic waves. We extended the analysis by considering its effects on seismic signals, especially on amplitude variation with offset (AVO). Taking the ratio of the array length to the dominant wavelength as a reference, we analyzed the attenuations of the peak amplitude and the peak frequency with the incident angle for the Ricker wavelet. When an array with a ratio of 1.0 is used, the peak amplitude and the peak frequency decay to around 50% and 80% respectively at an angle of 40°. The effect of an array is directivity-dependent, and it acts on the seismic record as a nonstationary filter. We present an inversion-based solution to remove the directional effects. On the approximation of the horizontal stratified medium, the horizontal velocity of the seismic reflection can be concisely expressed in terms of its reflection time, offset, and rms velocity, which facilitates the implementation of directional deconvolution. The method was tested using model-based and logging-based synthetic data.

  4. Salinomycin simultaneously induces apoptosis and autophagy through generation of reactive oxygen species in osteosarcoma U2OS cells.

    PubMed

    Kim, Sang-Hun; Choi, Young-Jun; Kim, Kwang-Youn; Yu, Sun-Nyoung; Seo, Young-Kyo; Chun, Sung-Sik; Noh, Kyung-Tae; Suh, Jeung-Tak; Ahn, Soon-Cheol

    2016-04-29

    Salinomycin, a polyether antibiotic, acts as a highly selective potassium ionophore. It was reported to anticancer activity on various cancer cell lines. In this study, salinomycin was examined on apoptosis and autophagy through generation of reactive oxygen species (ROS) in osteosarcoma U2OS cells. Apoptosis, autophagy, mitochondrial membrane potential (MMP) and ROS were analyzed using flow cytometry. Also, expressions of apoptosis- and autophagy-related proteins were determined by western blotting. As a result, salinomycin triggered apoptosis of U2OS cells, which was accompanied by change of MMP and cleavage of caspases-3 and poly (ADP-ribose) polymerase. And salinomycin increased the expression of autophagy-related protein and accumulation of acidic vesicular organelles (AVO). Salinomycin-induced ROS production promotes both apoptosis and autophagy, as evidenced by the result that treatment of N-acetyl-l-cysteine (NAC), a ROS scavenger, attenuated both apoptosis and autophagy. In addition, inhibition of autophagy by 3-methyladenine (3 MA) enhanced the salinoymcin-induced apoptosis. Taken together, these results suggested that salinomycin-induced autophagy, as a survival mechanism, might be a potential strategy through ROS regulation in cancer therapy. PMID:27033598

  5. NON-INVASIVE DETERMINATION OF THE LOCATION AND DISTRIBUTION OF FREE-PHASE DENSE NONAQUEOUS PHASE LIQUIDS (DNAPL) BY SEISMIC REFLECTION TECHNIQUES

    SciTech Connect

    Michael G. Waddell; William J. Domoracki; Tom J. Temples

    2001-05-01

    This semi-annual technical progress report is for part of Task 4 (site evaluation), on DOE contact number DE-AR26-98FT40369. The project had planned one additional deployment to another site other than Savannah River Site (SRS) or DOE Hanford. After the SUBCON midyear review in Albuquerque, NM, it was decided that two additional deployments would be performed. The first deployment is to test the feasibility of using non-invasive seismic reflection and AVO analysis as monitoring to assist in determining the effectiveness of Dynamic Underground Stripping (DUS) in removal of DNAPL. The Second deployment site is the Department of Defense (DOD) Charleston Navy Weapons Station, Solid Waste Management Unit 12 (SWMU-12) Charleston, SC was selected in consultation with National Energy Technology Laboratory (NETL) and DOD Navy Facilities Engineering Command Southern Division (NAVFAC) personnel. Base upon the review of existing data and due to the shallow target depth the project team has collected three Vertical Seismic Profiles (VSP) and experimental reflection line. At the time of preparing this report VSP data and experimental reflection line data has been collected and has have preliminary processing on the data sets.

  6. New seismic reflection techniques applied to gas recognition in the Rharb Basin, Morocco

    SciTech Connect

    Jabour, H.; Dakki, M. )

    1994-07-01

    The Rharb basin in Morocco is a Tertiary foreland filled by clastic series during the Miocene and Pliocene. This terrigenous influx, derived from the prerif to the northeast and the Meseta to the south, is characterized by a sandy episode during much of the Messinian and the Tortonian. The sand deposits were probably related to the uplift and major erosion of a part of the prerif during the sliding of an olistostrome (prerif nappe). Although most of the wells drilled in the basin have encountered biogenic gas accumulations, the problem still facing exploration in the area is seismic resolution and thin-bed tuning analysis. Recent studies using high seismic resolution techniques have permitted the authors to gain a deep insight into the stratigraphy and depositional environment of the thin sand reservoirs and their fluid content. AVO stratigraphy, inversion of seismic traces into acoustic impedance traces and seismic attributes calculation, and computing provide a remarkable example of the possibilities of depicting the lateral and vertical evolution of reservoir facies and localizing biogenic gas accumulations. Out of five recent exploratory wells drilled based on this new technique, three encountered gas-bearing sands with economic potential. Fifty-three amplitude anomalies have been identified and await processing.

  7. 7-Hydroxydehydronuciferine induces human melanoma death via triggering autophagy and apoptosis.

    PubMed

    Wu, Pei-Fang; Chiu, Chien-Chih; Chen, Chung-Yi; Wang, Hui-Min David

    2015-12-01

    Melanoma is the deadliest cancer. We identified 7-hydroxydehydronuciferine (7-HDNF) isolated from the leaves of Nelumbo nucifera Gaertn cv. Rosa-plena to be a bio-active agent that antagonizes melanoma tumor growth in mice xenograft model in vivo. Cell proliferation assay demonstrated strong anticancer effects of 7-HDNF to exhibit a dose-dependent behaviour and displayed minor cytotoxicities on normal human skin cells, including epidermal keratinocytes and melanocytes, and dermal fibroblasts. With acridine orange (AO) staining and flow analysis, we found 7-HDNF induced the formation of intracellular vacuoles and the augmentation of acidic vesicular organelles (AVO). The apoptotic cell death ratio was measured via two-dimensional flow cytometry by annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double stained to confirm the cellular membrane asymmetry lost. One-dimensional flow cytometric analysis showed 7-HDNF increased the cellular arrest in cell cycle at the G2/M phase. Through Western blot examinations, protein expressions were discovered to verify autophagy and apoptosis response mechanisms sharing the associated pathways. Finally, 7-HDNF presented a high-quality antimigratory activity in wound-healing assay. Overall, 7-HDNF presented high-quality anticancer bio-functions and inhibited melanoma tumor growth in vivo and in vitro. PMID:26174122

  8. Advanced Reservoir Imaging Using Frequency-Dependent Seismic Attributes

    SciTech Connect

    Fred Hilterman; Tad Patzek; Gennady Goloshubin; Dmitriy Silin; Charlotte Sullivan; Valeri Korneev

    2007-12-31

    Our report concerning advanced imaging and interpretation technology includes the development of theory, the implementation of laboratory experiments and the verification of results using field data. We investigated a reflectivity model for porous fluid-saturated reservoirs and demonstrated that the frequency-dependent component of the reflection coefficient is asymptotically proportional to the reservoir fluid mobility. We also analyzed seismic data using different azimuths and offsets over physical models of fractures filled with air and water. By comparing our physical model synthetics to numerical data we have identified several diagnostic indicators for quantifying the fractures. Finally, we developed reflectivity transforms for predicting pore fluid and lithology using rock-property statistics from 500 reservoirs in both the shelf and deep-water Gulf of Mexico. With these transforms and seismic AVO gathers across the prospect and its down-dip water-equivalent reservoir, fluid saturation can be estimated without a calibration well that ties the seismic. Our research provides the important additional mechanisms to recognize, delineate, and validate new hydrocarbon reserves and assist in the development of producing fields.

  9. Noninvasive determination of the location and distribution of DNAPL using advanced seismic reflection techniques.

    PubMed

    Temples, T J; Waddell, M G; Domoracki, W J; Eyer, J

    2001-01-01

    Recent advances in seismic reflection amplitude analysis (e.g., amplitude versus offset-AVO, bright spot mapping) technology to directly detect the presence of subsurface DNAPL (e.g., CCl4) were applied to 216-Z-9 crib, 200 West Area, DOE Hanford Site, Washington. Modeling to determine what type of anomaly might be present was performed. Model results were incorporated in the interpretation of the seismic data to determine the location of any seismic amplitude anomalies associated with the presence of high concentrations of CCl4. Seismic reflection profiles were collected and analyzed for the presence of DNAPL. Structure contour maps of the contact between the Hanford fine unit and the Plio/Pleistocene unit and between the Plio/Pleistocene unit and the caliche layer were interpreted to determine potential DNAPL flow direction. Models indicate that the contact between the Plio/Pleistocene unit and the caliche should have a positive reflection coefficient. When high concentrations of CCl4 are present, the reflection coefficient of this interface displays a noticeable positive increase in the seismic amplitude (i.e., bright spot). Amplitude data contoured on the Plio/Pleistocene-caliche boundary display high values indicating the presence of DNAPL to the north and east of the crib area. The seismic data agree well with the well control in areas of high concentrations of CCl4. PMID:11341013

  10. A real P-wave and its dependence on the presence of gas

    NASA Astrophysics Data System (ADS)

    Nikolaevskiy, V. N.

    2016-01-01

    Attenuation of seismic compression waves leads to the real existence of a fast P 1 wave in rocks which are fully saturated with dropping fluid and a slow P 2 wave in the rocks containing gas in their pores. This accounts for the seismic blanking zones below the gas horizons for the P 1 waves. Oscillations of gaseous inclusions ensure the energy transfer to the dominant frequencies which are different for the cases of passive seismic (few Hz) and active source seismic (10-20 Hz). The intervals of dominant frequencies are determined from the negative attenuation of these low-frequency waves. According to the observations and the suggested equation, random noise amplifies the signal at these frequencies. Thus, the P 2 waves at the dominant frequency of the active source seismics are applicable for elaborating on the details of the saturation of the production layer by hydrocarbons. The relation to the AVO method (Amplitude Variation with Offset) and dilatancy effect during the preparation of an earthquake is noted.

  11. Geologic map of Mount Gareloi, Gareloi Island, Alaska

    USGS Publications Warehouse

    Coombs, Michelle L.; McGimsey, Robert G.; Browne, Brandon L.

    2012-01-01

    As part of an effort to both monitor and study all historically active volcanoes in Alaska, the Alaska Volcano Observatory (AVO) undertook a field program at Mount Gareloi in the summer of 2003. During a month-long period, seismic networks were installed at Mount Gareloi and the neighboring Tanaga volcanic cluster. During this time, we undertook the first geologic field study of the volcano since Robert Coats visited Gareloi Island for four days in 1946. Understanding the geology of this relatively small island is important from a hazards perspective, because Mount Gareloi lies beneath a heavily trafficked air route between North America and Asia and has frequently erupted airborne ash since 1760. At least two landslides from the island have deposited debris on the sea floor; thus, landslide-generated tsunamis are also a potential hazard. Since seismic instruments were installed in 2003, they have detected small but consistent seismic signals from beneath Mount Gareloi's edifice, suggesting an active hydrothermal system. Mount Gareloi is also important from the standpoint of understanding subduction-related volcanism, because it lies in the western portion of the volcanically active arc, where subduction is oblique to the arc front. Understanding the compositional evolution of Mount Gareloi fills a spatial gap in along-arc studies.

  12. Central and peripheral response to incremental cycling exercise in older untrained active men: a comparison of those in-between.

    PubMed

    O'Neill, C D; Kimmerly, D S; Dogra, S

    2016-06-20

    The aim of this study was to compare the central and peripheral components of cardiorespiratory fitness during incremental to maximal exercise between older men who were either recreational athletes (RA) or leisurely active (LA) men, i.e., those who fall between trained and untrained. This was a cross-sectional study in which all subjects completed an exercise test on a cycle ergometer. Maximal oxygen consumption (VO(2max)) and ventilatory threshold (VT) were assessed using gas analysis, and central components of VO(2max) were assessed using a non-invasive thoracic bio-impedance device. VO(2max) (RA: 45.1+/-4.8 ml/kg/min; LA: 32.2+/-4.6 ml/kg/min, pa-v)O(2diff)) were observed between groups. In conclusions, training volume appears to influence central components of cardiorespiratory fitness among a matched sample of older men who are neither trained nor untrained. This builds a case for increasing the volume of training to preserve cardiorespiratory fitness among older men. PMID:26447523

  13. Transmission imaging in heterogeneous media

    NASA Astrophysics Data System (ADS)

    Bongajum, E. L.; Meng, Y.; Milkereit, B.

    2010-12-01

    Wave propagation in heterogeneous media is characterized by amplitude, traveltime, and spectral fluctuations that reflect the variations in elastic properties (e.g. Vp, Vs, density). Variations in physical rock properties exist at different scales and occasionally result in effective anisotropy in medium parameters. If the variations in rock properties can be characterized from existing information such as logs, then it becomes possible to incorporate this information in wave modeling algorithms to understand its impact on acquisition design, processing of seismic waves for velocity information, AVO analysis as well as reverse time migration (RTM) routines. This study evaluates some of these aspects by using transmitted (direct) waves. When the variations exist over large scale lengths, RTM can be successfully implemented on Vertical Seismic Profiling (VSP) data in order to image the interface between two inhomogeneities as well as characterize the velocity distribution beyond the borehole location. However, when the existing geology causes anisotropy in the variability of the physical rock properties, the use of transmitted waves becomes strongly dependent on the acquisition geometry. In this circumstance, travel time fluctuations are influenced by the strength of the perturbations of the elastic parameters and the direction with the least variability (large scale lengths) in these parameters. This has according implications for seismic imaging in hardrock environment as well microseismic imaging applications.

  14. Computational methods for improving the resolution of subsurface seismic images. Progress report, September 15, 1991--September 14, 1993

    SciTech Connect

    Larner, K.; Hale, D.; Bleistein, N.; Cohen, J.

    1993-05-01

    Our interactive modeling for Gaussian beam modeling in two-dimensional, triangulated complex geologic structure, has been generalized to include transmission losses at interfaces, and density and Q-characterization of attenuation in layers. Also, multiple reflections and the option to model data from VSP acquisition geometry have been included. Shortcomings when the structure contains first-order discontinuities, however, limit the full geologic complexity that presently can be modeled by the Gaussian beam method. Other studies of wave filtering that arises for waves propagating nearly parallel to bedding reveal the importance of tunneling evanescent filtering on the propagating wavelet. Likewise, for reflections from steep interfaces, we have developed a dip-divergence correction to compensate for shortcomings in the conventional divergence correction for energy spreading. A new direction this past year, which we will be pursuing in the year ahead is analysis of errors in migration and dip-moveout (DMO) that arise when conventional imaging processing, which ignores anisotropy, is applied to data acquired where the subsurface is transversely isotropic. We are also developing approaches for taking anisotropy into account in these important imaging processes. Similarly, we have developed an efficient approach to performing DMO on P-SV-mode-converted data. Our interests in taking anisotropy into account have led us to study the importance of anisotropy in the overburden on reflection amplitude variations with offset (AVO).

  15. Seismic attribute for hydrocarbon expressions in stack section

    NASA Astrophysics Data System (ADS)

    Farfour, Mohammed; Yoon, Wang Jung

    2014-12-01

    Stacking process in seismic data processing is a simple and powerful tool commonly used to remove undesired random noise and enhance signal to noise ratio. Basically, the process averages traces from prestack gathers (angles or CDPs) so that they present normal-incidence reflections in stack sections. Experience has showed that hydrocarbons-bearing sediments are generally characterized by anomalous amplitude changes relative to their background from an offset to another. This can result in interesting seismic expressions in the stack section that can help identify reservoirs and delineate their extensions. This paper investigates the conceptual assumptions behind stacking and amplitude variation with offset (AVO). A new attribute is presented and used to detect and extract anomalies associated with hydrocarbon sand reservoirs from their background. The attribute has been examined on real datasets from different fields. The seismic-weighted instantaneous energy attribute showed excellent results in delineating bright spots associated with shallow gas accumulations as well as revealing stratigraphic features of two productive sand-filled channels. Indeed, the paper provides a new insight into seismic stack data analysis and interpretation.

  16. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-12-01

    We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

  17. Variation of shear and compressional wave modulus upon saturation for pure pre-compacted sands

    NASA Astrophysics Data System (ADS)

    Bhuiyan, M. H.; Holt, R. M.

    2016-07-01

    Gassmann's fluid substitution theory is commonly used to predict seismic velocity change upon change in saturation, and is hence essential for 4-D seismic and AVO studies. This paper addresses the basics assumptions of the Gassmann theory, in order to see how well they are fulfilled in controlled laboratory experiments. Our focus is to investigate the sensitivity of shear modulus to fluid saturation, and the predictability of Gassmann's fluid substitution theory for P-wave modulus. Ultrasonic P- and S-wave velocities in dry and saturated (3.5 wt per cent NaCl) unconsolidated clean sands (Ottawa and Columbia) were measured in an oedometer test system (uniaxial strain conditions) over a range of 0.5-10 MPa external vertical stress. This study shows shear modulus hardening upon brine saturation, which is consistent with previous data found in the literature. Analysis of the data shows that most of the hardening of the ultrasonic shear modulus may be explained by Biot dispersion. Isotropic Gassmann's fluid substitution is found to underestimate the P-wave modulus upon fluid saturation. However, adding the Biot dispersion effect improves the prediction. More work is required to obtain good measurements of parameters influencing dispersion, such as tortuosity, which is very ambiguous and challenging to measure accurately.

  18. Observation of volcanoes through webcams: Tools and techniques

    NASA Astrophysics Data System (ADS)

    Lovick, J.; Lawlor, O.; Dean, K.; Dehn, J.

    2008-12-01

    This work explores techniques for deriving quantitative data from webcam observations. It illustrates the role that webcams can play in volcano monitoring, and shows our recently developed tools for the collation and dissemination of this data. Over the past 5 years, digital cameras have been installed at a number of volcanoes to allow the general public to see volcanic activity from the comfort of their own homes. In the last 3 years these webcam images have become part of the twice-daily volcano monitoring report by the remote sensing team of the Alaska Volcano Observatory (AVO). To allow comprehensive and systematic analysis, a database has been created containing all AVO webcam images as well as images from St. Helens and three KVERT webcams for Bezymianny, Klyucheskoy and Shiveluch. In total, some 1.6 million images are currently held. The number increases daily as new images are obtained and processed. The database holds additional information about each image such as both image-wide and localized-region statistics. Our tools have been developed to answer specific questions utilizing this data. Of the current 1.6 million images in the database, a very small percentage is considered interesting for volcano monitoring; the remainder can be ignored due to complete cloud cover or (for nocturnal images) lack of luminescence. We have developed a tool for automatically isolating uninteresting images (primarily based on image histograms.) Uninteresting images are tagged, which allows for them to be excluded from further processing. Our next tool is an automated system for isolating and measuring nocturnal luminescence. This tool has been developed using images of St. Helens and is being extended to work with other webcams where nightime lava glow have been seen. The system works by first minimizing each camera's unique dark current and amplification noise signals and then establishes if any pixels fulfill a number of criteria that would indicate they are real "glow

  19. The 2013 Eruptions of Pavlof and Mount Veniaminof Volcanoes, Alaska

    NASA Astrophysics Data System (ADS)

    Schneider, D. J.; Waythomas, C. F.; Wallace, K.; Haney, M. M.; Fee, D.; Pavolonis, M. J.; Read, C.

    2013-12-01

    Pavlof Volcano and Mount Veniaminof on the Alaska Peninsula erupted during the summer of 2013 and were monitored by the Alaska Volcano Observatory (AVO) using seismic data, satellite and web camera images, a regional infrasound array and observer reports. An overview of the work of the entire AVO staff is presented here. The 2013 eruption of Pavlof Volcano began on May 13 after a brief and subtle period of precursory seismicity. Two volcano-tectonic (VT) earthquakes at depths of 6-8 km on April 24 preceded the onset of the eruption by 3 weeks. Given the low background seismicity at Pavlof, the VTs were likely linked to the ascent of magma. The onset of the eruption was marked by subtle pulsating tremor that coincided with elevated surface temperatures in satellite images. Activity during May and June was characterized by lava fountaining and effusion from a vent near the summit. Seismicity consisted of fluctuating tremor and numerous explosions that were detected on an infrasound array (450 km NE) and as ground-coupled airwaves at local and distant seismic stations (up to 650 km). Emissions of ash and sulfur dioxide were observed in satellite data extending as far as 300 km downwind at altitudes of 5-7 km above sea level. Ash collected in Sand Point (90 km E) were well sorted, 60-150 micron diameter juvenile glass shards, many of which had fluidal forms. Automated objective ash cloud detection and cloud height retrievals from the NOAA volcanic cloud alerting system were used to evaluate the hazard to aviation. A brief reconnaissance of Pavlof in July found that lava flows on the NW flank consist of rubbly, clast rich, 'a'a flows composed of angular blocks of agglutinate and rheomorphic lava. There are at least three overlapping flows, the longest of which extends about 5 km from the vent. Eruptive activity continued through early July, and has since paused or stopped. Historical eruptions of Mount Veniaminof volcano have been from an intracaldera cone within a 10

  20. The 2008 Eruption of Kasatochi Volcano, Central Aleutian Islands, Alaska: Reconnaissance Observations and Preliminary Physical Volcanology

    NASA Astrophysics Data System (ADS)

    Waythomas, C. F.; Schneider, D. J.; Prejean, S. G.

    2008-12-01

    The August 7, 2008 eruption of Kasatochi volcano was the first documented historical eruption of this small (3 x 3 km) island volcano with a 1 km2 lake filled crater in the central Aleutian Islands of Alaska. Reports of previous Kasatochi eruptions are unconfirmed and lacking in detail and little is known about the eruptive history. Three explosively-generated ash plumes reaching altitudes of 15 to 20 km were observed in satellite data and were preceded by some of the most intense seismicity yet recorded by the Alaska Volcano Observatory (AVO) seismic network. Eruptive products on Kasatochi Island observed on August 22 and 23 consist of pumice-bearing, lithic-rich pyroclastic-flow deposits overlain by a 1-2 m thick sequence of fine- grained pyroclastic-surge, and -fall deposits all exposed at the coastline. These deposits completely blanket Kasatochi Island to a depth of many meters. Pyroclastic flows entered the sea and extended the coastline 300-400 m beyond prominent wave cut cliffs and sea stacks. Tide gauge data from Adak Island, 80 km to the west, indicate a small tsunami with maximum water amplitude of 20 cm, was initiated during the eruption. Kasatochi volcano lacks a real-time seismic monitoring network. Seismic activity was detected by AVO instruments on Great Sitkin Island 40 km to the west, and thus the timing of eruptive events is approximate. The eruption began explosively at 2201 UTC on August 7, and was followed by at least two additional strong eruptive bursts at 0150 UTC and 0435 UTC, August 8. Satellite data show a significant ash cloud associated with the 0435 UTC event followed by at least 14 hours of continuous ash emission. The lack of a strong ash signature in satellite data suggest that the first two plumes were ash poor. Satellite data also show a large emission of SO2 that entered the stratosphere. Correlation of eruptive periods with deposits on the island is not yet possible, but it appears that pyroclastic flows were emplaced during

  1. Integrating sequence stratigraphy and rock-physics to interpret seismic amplitudes and predict reservoir quality

    NASA Astrophysics Data System (ADS)

    Dutta, Tanima

    improves the predictions of shear wave velocities. In addition, we provide empirical relations on normal compaction depth trends of porosity, velocities, and VP/VS ratio for shale and clean sands in shallow, supra-salt sediments in the Gulf of Mexico. Next, we identify probable spatial trends of sand/shale ratio and sorting as predicted by the conventional sequence stratigraphic model in minibasin settings (spill-and-fill model). These spatial trends are evaluated using well data from offshore West Africa, and the same well data are used to calibrate rock physics models (modified soft-sand model) that provide links between P-impedance and quartz/clay ratio, and sorting. The spatial increase in sand/shale ratio and sorting corresponds to an overall increase in P-impedance, and AVO intercept and gradient. The results are used as a guide to interpret sedimentological parameters from seismic attributes, away from the well locations. We present a quantitative link between carbonate cement and seismic attributes by combining stratigraphie cycles and the rock physics model (modified differential effective medium model). The variation in carbonate cement volume in West Africa can be linked with two distinct stratigraphic cycles: the coarsening-upward cycles and the fining-upward cycles. Cemented sandstones associated with these cycles exhibit distinct signatures on P-impedance vs. porosity and AVO intercept vs. gradient crossplots. These observations are important for assessing reservoir properties in the West Africa as well as in other analogous depositional environments. Finally, we investigate the relationship between seismic velocities and time temperature index (TTI) using basin and petroleum system modeling at Rio Muni basin, West Africa. We find that both VP and VS increase exponentially with TTI. The results can be applied to predict TTI, and thereby thermal maturity, from observed velocities.

  2. Introduction to Augustine Volcano and Overview of the 2006 Eruption

    NASA Astrophysics Data System (ADS)

    Nye, C. J.

    2006-12-01

    This overview represents the combined efforts of scores of people, including Alaska Volcano Observatory staff from the US Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys; additional members of those agencies outside of AVO; and volcanologists from elsewhere. Augustine is a young, and therefore small island volcano in the Cook Inlet region of the eastern Aleutian arc. It is among the most active volcanoes in the arc, with six major historic eruptions, and a vigorous eruptive history going back at least 2,500 years. Eruptions typically begin explosively, and finish with the extrusion of domes and sometimes short, steep lava flows. At least 14 times (most recently in 1883) the -summit has become over-steepened and failed, producing debris avalanches which reached tidewater. Magmas within each of the well-studied eruptions are crystal-rich andesite spanning up to seven weight percent silica. Mixing and mingling are ubiquitous and occur at scales from meters to microns. In general, magmagenesis at Augustine is open, messy, and transcrustal. The 2006 eruption was broadly similar to the 20th century eruptions. Unrest began midway through 2005, with steadily increasing numbers of microearthquakes and continuous inflation of the edifice. By mid-December there were obvious morphological and thermal changes at the summit, as well as phreatic explosions and more passive venting of S-rich gasses. In mid-January 2006 phreatomagmatic explosions gave way to magmatic explosions, producing pyroclastic flows dominated by low-silica andesite, as well as lahars, followed by a small summit dome. In late January the nature of seismicity, eruptive style, and type of erupted magma all changed, and block-and-ash flows of high-silica, crystal-rich andesite were emplaced as the edifice deflated. Re-inflation well below the edifice and low-level effusion continued through February. During the second week

  3. Eruption Forecasting: Success and Surprise at Kasatochi and Okmok Volcanoes

    NASA Astrophysics Data System (ADS)

    Prejean, S.; Power, J.; Brodsky, E.

    2008-12-01

    In the summer of 2008, the Alaska Volcano Observatory (AVO) successfully forecast eruption at an unmonitored volcano, Kasatochi, and was unable to forecast eruption at a well monitored volcano, Okmok. We use these case studies to explore the limitations and opportunities of seismically monitored and unmonitored systems and to evaluate situations when we can expect to succeed and when we must expect to fail in eruption forecasting. Challenges in forecasting eruptions include interpreting seismicity in context of volcanic history, developing a firm understanding of distance scales over which pre- and co-eruptive seismic signals are observed, and improving our ability to discriminate processes causing tremor. Kasatochi Volcano is a 3 km wide island in the central Aleutian Islands with no confirmed historical activity. Little is known about the eruptive history of the volcano. It was not considered an immediate threat until 3 days prior to eruption. A report of ground shaking by a biology field crew on the island on August 4 was the first indication of unrest. On August 6 a vigorous seismic swarm became apparent on the nearest seismic stations 40 km distant. The aviation color code/volcano alert level at Kasatochi was increased to Yellow/Advisory in response to increasing magnitude and frequency of earthquakes. The color code/alert level was increased to Orange/Watch on August 7 when volcanic tremor was observed in the wake of the largest earthquake in the sequence, a M 5.6. Three hours after the onset of volcanic tremor, eruption was confirmed by satellite data and the color code/alert level increased to Red/Warning. Eruption forecasting was possible only due to the exceptionally large moment release of pre-eruptive seismicity. The key challenge in evaluating the situation was distinguishing between tectonic activity and a volcanic swarm. It is likely there were weeks to months of precursory seismicity, however little instrumental record exists due to the lack of a

  4. Structure and physical properties of the Earth's crust in the Central Metasedimentary Belt, Grenville Province, Ontario from near vertical seismic reflection data

    NASA Astrophysics Data System (ADS)

    Roy, Baishali

    transparent to the reflection seismic method and the pattern recognition method failed to improve the Moho signature except for the northern end of Line 32, where signals are interpreted in this study to represent the under thrusting of the Archaean crust. The poor reflectivity of the lower crust in the study area can be explained with scattering and attenuation of energy, limiting depths of signal penetration. The second part of the thesis is aimed at studying the physical properties of the crust such as the Poisson's ratio and velocity variations along the reflectors. Emphasis is laid on using AVO (amplitude versus offset variation) as a tool for this and obtaining relevant geological information. AVO data was extracted from the CDP gathers and inverted to obtain theoretical models. Non-uniqueness is a major problem in this inversion, which has been constrained to a certain extent by the reflection coefficients. Results indicate a bimodal pattern for the Poisson's ratio contrasts and a unimodal pattern for the velocity contrast. This may arise from changes in lithology, anisotropy or pore fluids that effect the wave velocities. Results, when tied to the geology, reveal that major crustal reflectors are associated with a fall in both Poisson's ratio and velocity contrast. Further studies on the nature of these reflectors should be done to understand the reason behind this reflectivity.

  5. Augustine Volcano, Cook Inlet, Alaska (January 12, 2006)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Since last spring, the U.S. Geological Survey's Alaska Volcano Observatory (AVO) has detected increasing volcanic unrest at Augustine Volcano in Cook Inlet, Alaska near Anchorage. Based on all available monitoring data, AVO regards that an eruption similar to 1976 and 1986 is the most probable outcome. During January, activity has been episodic, and characterized by emission of steam and ash plumes, rising to altitudes in excess of 9,000 m (30,000 ft), and posing hazards to aircraft in the vicinity. An ASTER image was acquired at 12:42 AST on January 12, 2006, during an eruptive phase of Augustine. The perspective rendition shows the eruption plume derived from the ASTER image data. ASTER's stereo viewing capability was used to calculate the 3-dimensional topography of the eruption cloud as it was blown to the south by prevailing winds. From a maximum height of 3060 m (9950 ft), the plume cooled and its top descended to 1900 m (6175 ft). The perspective view shows the ASTER data draped over the plume top topography, combined with a base image acquired in 2000 by the Landsat satellite, that is itself draped over ground elevation data from the Shuttle Radar Topography Mission. The topographic relief has been increased 1.5 times for this illustration. Comparison of the ASTER plume topography data with ash dispersal models and weather radar data will allow the National Weather Service to validate and improve such models. These models are used to forecast volcanic ash plume trajectories and provide hazard alerts and warnings to aircraft in the Alaska region.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous

  6. Micro-CT applications to Seismic Monitoring of EOR and Carbon Sequestration Sites

    NASA Astrophysics Data System (ADS)

    Mur, A. J.; Crandall, D.; Purcell, C. C.; Bromhal, G. S.; Soong, Y.; Warzinski, R.; McClendon, B.; Harbert, W.

    2011-12-01

    In order to monitor a CO2 injection site with reflection seismic and VSP surveying, the dynamic rock matrix must be thoroughly understood. We present our results and approach to upscale micro-scale rock matrix properties to reservoir scale and seismic frequency ranges based on theoretical rock wave propagation models and show the richness of useful data produced by micro computed tomography (CT). We have acquired and processed CT images of limestone, sandstone and synthetic samples to gain understanding of 3-D pore orientation, pore volume distribution and pore surface area geometry from 1.25 to 4 micrometer-per-pixel resolution. By comparing CT scans from before and after timed CO2 exposures(Figure 1 shows dissolution along high aspect ratio crack in limestone sample), rock density and pore volume changes relative to time are quantified. In a 19% porosity limestone sample, our analysis identifies and describes over twelve thousand pores in a 26 cubic millimeter volume at a resolution of 3.92 micron/pixel. We produce a digital rock mesh with which we simulate fluid flow in the matrix. As opposed to large scale plume predictions, this small scale flow model helps predict how CO2 will be distributed in a zone that is under a constant flux of CO2. By observing available reactive surface area of the porosity and mass change over a series of time increments, we chemically model limestone-CO2 interactions to predict how, over time, a carbonate reservoir will change due to storage of CO2. This porosity and density change model is applied to a larger-scale reservoir model that detects the presence of CO2 density signatures using AVO (amplitude variation with offset) and VSP (vertical seismic profile) techniques. This application produces theoretical seismic volumes of uncompromised future reservoirs that can be compared to repeat surveys for leak detection.

  7. Rock physics template from laboratory data for carbonates

    NASA Astrophysics Data System (ADS)

    Gegenhuber, Nina; Pupos, Judit

    2015-03-01

    Information about compressional and shear wave velocity or their ratio gives the possibility to interpret data concerning lithology and pore content, like the AVO analysis. Our data set (dolomite and limestone samples from Austria) is presented in a rock physics template, which is used as a tool for seismic interpretation for lithology and pore fluid characterization. In the rock physics template the ratio of compressional (vp) and shear wave (vs) velocity is plotted versus the acoustic impedance. Additionally presented are calculated model lines for the description and interpretation of the measured data. Used are the model by Kuster and Tosköz and the Hashin-Shtrikman bounds. Compressional and shear wave velocity on dry and brine saturated samples are determined in the laboratory. The rock physics template displays a clear separation between dry and saturated measured data. Additionally, the saturated measured data show a "shear weakening effect" that has been reported in the literature before by other researchers. The Kuster and Toksöz model is able to describe the measured data fairly well. However, different aspect ratios are needed to match the different vp and vs data for the different rock types. Additionally this model type could not describe our data in the rock physics template. The calculated Hashin-Shtrikman bounds for the rock physics template show good results for the saturated samples. The upper bound and the 75% and 50% of the upper bound can describe the measured data and can be used for an interpretation. For the dry measured data the correlations did not work sufficiently well.

  8. Chronology and References of Volcanic Eruptions and Selected Unrest in the United States, 1980-2008

    USGS Publications Warehouse

    Diefenbach, Angela K.; Guffanti, Marianne; Ewert, John W.

    2009-01-01

    The United States ranks as one of the top countries in the world in the number of young, active volcanoes within its borders. The United States, including the Commonwealth of the Northern Mariana Islands, is home to approximately 170 geologically active (age <10,000 years) volcanoes. As our review of the record shows, 30 of these volcanoes have erupted since 1980, many repeatedly. In addition to producing eruptions, many U.S. volcanoes exhibit periods of anomalous activity, unrest, that do not culminate in eruptions. Monitoring volcanic activity in the United States is the responsibility of the U.S. Geological Survey (USGS) Volcano Hazards Program (VHP) and is accomplished with academic, Federal, and State partners. The VHP supports five Volcano Observatories - the Alaska Volcano Observatory (AVO), Cascades Volcano Observatory (CVO), Yellowstone Volcano Observatory (YVO), Long Valley Observatory (LVO), and Hawaiian Volcano Observatory (HVO). With the exception of HVO, which was established in 1912, the U.S. Volcano Observatories have been established in the past 27 years in response to specific volcanic eruptions or sustained levels of unrest. As understanding of volcanic activity and hazards has grown over the years, so have the extent and types of monitoring networks and techniques available to detect early signs of anomalous volcanic behavior. This increased capability is providing us with a more accurate gauge of volcanic activity in the United States. The purpose of this report is to (1) document the range of volcanic activity that U.S. Volcano Observatories have dealt with, beginning with the 1980 eruption of Mount St. Helens, (2) describe some overall characteristics of the activity, and (3) serve as a quick reference to pertinent published literature on the eruptions and unrest documented in this report.

  9. Observations of deep long-period (DLP) seismic events beneath Aleutian arc volcanoes; 1989-2002

    USGS Publications Warehouse

    Power, J.A.; Stihler, S.D.; White, R.A.; Moran, S.C.

    2004-01-01

    Between October 12, 1989 and December 31, 2002, the Alaska Volcano Observatory (AVO) located 162 deep long-period (DLP) events beneath 11 volcanic centers in the Aleutian arc. These events generally occur at mid- to lower-crustal depths (10-45 km) and are characterized by emergent phases, extended codas, and a strong spectral peak between 1.0 and 3.0 Hz. Observed wave velocities and particle motions indicate that the dominant phases are P- and S-waves. DLP epicenters often extend over broad areas (5-20 km) surrounding the active volcanoes. The average reduced displacement of Aleutian DLPs is 26.5 cm2 and the largest event has a reduced displacement of 589 cm2 (or ML 2.5). Aleutian DLP events occur both as solitary events and as sequences of events with several occurring over a period of 1-30 min. Within the sequences, individual DLPs are often separated by lower-amplitude volcanic tremor with a similar spectral character. Occasionally, volcano-tectonic earthquakes that locate at similar depths are contained within the DLP sequences. At most, Aleutian volcanoes DLPs appear to loosely surround the main volcanic vent and occur as part of background seismicity. A likely explanation is that they reflect a relatively steady-state process of magma ascent over broad areas in the lower and middle portions of the crust. At Mount Spurr, DLP seismicity was initiated by the 1992 eruptions and then slowly declined until 1997. At Shishaldin Volcano, a short-lived increase in DLP seismicity occurred about 10 months prior to the April 19, 1999 eruption. These observations suggest a link between eruptive activity and magma flux in the mid- to lower-crust and uppermost mantle.

  10. Integrated seismic study of naturally fractured tight gas reservoirs. Final report, September 1991--January 1995

    SciTech Connect

    Mavko, G.; Nur, A.

    1995-01-01

    The approach in this project has been to integrate the principles of rock physics into a quantitative processing and interpretation scheme that exploits, where possible, the broader spectrum of fracture zone signatures: (1) anomalous compressional and shear wave velocity; (2) Q and velocity dispersion; (3) increased velocity anisotropy; (4) amplitude vs. offset (AVO) response, and (5) variations in frequency content. As part of this the authors have attempted to refine some of the theoretical rock physics tools that should be applied in any field study to link the observed seismic signatures to the physical/geologic description of the fractured rock. The project had 3 key elements: (1) rock physics studies of the anisotropic viscoelastic signatures of fractured rocks, (2) acquisition and processing of seismic reflection field data, and (3) interpretation of seismic and well log data. The study site is in a producing field operated by Amoco and Arco at the southern boundary of the Powder River basin in Wyoming. During the winter of 1992--1993 the authors collected about 50 km of 9-component reflection seismic data and obtained existing log data from several wells in the vicinity. The paper gives background information on laboratory studies, seismic field studies of fracture anisotropy, and the problem of upscaling from the laboratory to the field. It discusses fluid effects on seismic anisotropy and a method for predicting stress-induced seismic anisotropy. Then results from the field experiment are presented and discussed: regional geologic framework and site description; seismic data acquisition; shear wave data and validation; and P-wave data analysis. 106 refs., 52 figs.

  11. Development of Scientific Tools at the USGS to Prepare for Ash-Producing Eruptions

    NASA Astrophysics Data System (ADS)

    Guffanti, M.; Mastin, L. G.; Wallace, K.; Schneider, D. J.; Neal, C. A.

    2015-12-01

    The U.S. Geological Survey has undertaken a focused effort over the past several years to develop scientific tools to improve capabilities to forecast, assess, and mitigate the adverse impacts of ash-producing eruptions. To improve forecasting capabilities, USGS scientists developed a Eulerian ash dispersion and deposition model, Ash3D, with output designed for operational use by other agencies. For ashfall hazards, Ash3D output includes forecasts of time of arrival and duration of ashfall, as well as traditional isopach maps. We coordinated with colleagues at the National Weather Service in Alaska to ensure Ash3D output is useable by NWS in its official ashfall advisories, and we are developing methods to generate long-term probabilistic ashfall hazard maps for DOE. For ash-cloud hazards, Ash3D output includes animations of cloud height, mass load, concentration, and arrival times over airports. To improve assessment capabilities, diverse approaches were pursued: a portable Doppler radar was acquired and successfully used to characterize ash plumes during the 2009 eruption of Redoubt Volcano in Alaska; a database system was created to manage ashfall collection and observations, including by the public ('Is Ash Falling?' at www.avo.alaska.edu/ashfall/ashreport.php); a display-and-analysis tool was developed that accesses public satellite data from a variety of sensors and platforms ('Volcview' at volcview.wr.usgs.gov/). To improve mitigation capabilities, the USGS hosts a website (volcanoes.usgs.gov/ash), developed by the partners of IAVCEI's International Volcanic Ashfall Impacts Working Group and recently revamped, that provides practical guidance about how to prepare for and recover from ash eruptions, organized by affected sector (buildings, transportation, power supply, health, agriculture, water supply, communications). With these various tools now available, scientists and citizenry are better prepared for ash eruptions.

  12. Probing the homogeneity of the isotopic composition and molar mass of the ‘Avogadro’-crystal

    NASA Astrophysics Data System (ADS)

    Pramann, Axel; Lee, Kyoung-Seok; Noordmann, Janine; Rienitz, Olaf

    2015-12-01

    Improved measurements on silicon crystal samples highly enriched in the 28Si isotope (known as ‘Si28’ or AVO28 crystal material) have been carried out at PTB to investigate local isotopic variations in the original crystal. This material was used for the determination of the Avogadro constant NA and therefore plays an important role in the upcoming redefinition of the SI units kilogram and mole, using fundamental constants. Subsamples of the original crystal have been extensively studied over the past few years at the National Research Council (NRC, Canada), the National Metrology Institute of Japan (NMIJ, Japan), the National Institute of Standards and Technology (NIST, USA), the National Institute of Metrology (NIM, People’s Republic of China), and multiple times at PTB. In this study, four to five discrete, but adjacent samples were taken from three distinct axial positions of the crystal to obtain a more systematic and comprehensive understanding of the distribution of the isotopic composition and molar mass throughout the crystal. Moreover, improved state-of-the-art techniques in the experimental measurements as well as the evaluation approach and the determination of the calibration factors were utilized. The average molar mass of the measured samples is M  =  27.976 970 12(12) g mol-1 with a relative combined uncertainty uc,rel(M)  =  4.4 ×10-9. This value is in astounding agreement with the values of single samples measured and published by NIST, NMIJ, and PTB. With respect to the associated uncertainties, no significant variations in the molar mass and the isotopic composition as a function of the sample position in the boule were observed and thus could not be traced back to an inherent property of the crystal. This means that the crystal is not only ‘homogeneous’ with respect to molar mass but also has predominantly homogeneous distribution of the three stable Si isotopes.

  13. Why Are High-Altitude Natives So Strong at Altitude? Maximal Oxygen Transport to the Muscle Cell in Altitude Natives.

    PubMed

    Lundby, Carsten; Calbet, Jose A L

    2016-01-01

    In hypoxia aerobic exercise performance of high-altitude natives is suggested to be superior to that of lowlanders; i.e., for a given altitude natives are reported to have higher maximal oxygen uptake (VO2max). The likely basis for this is a higher pulmonary diffusion capacity, which in turn ensures higher arterial O2 saturation (SaO2) and therefore also potentially a higher delivery of O2 to the exercising muscles. This review focuses on O2 transport in high-altitude Aymara. We have quantified femoral artery O2 delivery, arterial O2 extraction and calculated leg VO2 in Aymara, and compared their values with that of acclimatizing Danish lowlanders. All subjects were studied at 4100 m. At maximal exercise SaO2 dropped tremendously in the lowlanders, but did not change in the Aymara. Therefore arterial O2 content was also higher in the Aymara. At maximal exercise however, fractional O2 extraction was lower in the Aymara, and the a-vO2 difference was similar in both populations. The lower extraction levels in the Aymara were associated with lower muscle O2 conductance (a measure of muscle diffusion capacity). At any given submaximal exercise intensity, leg VO2 was always of similar magnitude in both groups, but at maximal exercise the lowlanders had higher leg blood flow, and hence also higher maximum leg VO2. With the induction of acute normoxia fractional arterial O2 extraction fell in the highlanders, but remained unchanged in the lowlanders. Hence high-altitude natives seem to be more diffusion limited at the muscle level as compared to lowlanders. In conclusion Aymara preserve very high SaO2 during hypoxic exercise (likely due to a higher lung diffusion capacity), but the effect on VO2max is reduced by a lower ability to extract O2 at the muscle level. PMID:27343089

  14. Station corrections for the Katmai Region Seismic Network

    USGS Publications Warehouse

    Searcy, Cheryl K.

    2003-01-01

    Most procedures for routinely locating earthquake hypocenters within a local network are constrained to using laterally homogeneous velocity models to represent the Earth's crustal velocity structure. As a result, earthquake location errors may arise due to actual lateral variations in the Earth's velocity structure. Station corrections can be used to compensate for heterogeneous velocity structure near individual stations (Douglas, 1967; Pujol, 1988). The HYPOELLIPSE program (Lahr, 1999) used by the Alaska Volcano Observatory (AVO) to locate earthquakes in Cook Inlet and the Aleutian Islands is a robust and efficient program that uses one-dimensional velocity models to determine hypocenters of local and regional earthquakes. This program does have the capability of utilizing station corrections within it's earthquake location proceedure. The velocity structures of Cook Inlet and Aleutian volcanoes very likely contain laterally varying heterogeneities. For this reason, the accuracy of earthquake locations in these areas will benefit from the determination and addition of station corrections. In this study, I determine corrections for each station in the Katmai region. The Katmai region is defined to lie between latitudes 57.5 degrees North and 59.00 degrees north and longitudes -154.00 and -156.00 (see Figure 1) and includes Mount Katmai, Novarupta, Mount Martin, Mount Mageik, Snowy Mountain, Mount Trident, and Mount Griggs volcanoes. Station corrections were determined using the computer program VELEST (Kissling, 1994). VELEST inverts arrival time data for one-dimensional velocity models and station corrections using a joint hypocenter determination technique. VELEST can also be used to locate single events.

  15. Sonodynamic therapy induces the interplay between apoptosis and autophagy in K562 cells through ROS.

    PubMed

    Su, Xiaomin; Wang, Pan; Yang, Shuang; Zhang, Kun; Liu, Quanhong; Wang, Xiaobing

    2015-03-01

    Sonodynamic therapy (SDT) is a relatively new approach in the treatment of various cancers including leukemia cells. The aim of this study is to investigate the occurrence of apoptosis and autophagy after treated by protoporphyrin IX (PpIX)-mediated SDT (PpIX-SDT) on human leukemia K562 cells as well as the relationship between them. Firstly, mitochondrial-dependent apoptosis was observed through morphological observation and biochemical analysis. Meanwhile, SDT was shown to induce autophagy in K562 cells, which caused an increase in EGFP-LC3 puncta cells, a conversion of LC3 II/I, formation of acidic vesicular organelles (AVOs) and co-localization between LC3 and LAMP2 (a lysosome marker). Besides, pretreatment with autophagy inhibitor 3-MA or bafilomycin A1 was shown to provide protection against autophagy and to enhance SDT-induced apoptosis and necrosis, while the apoptosis suppressor z-VAD-fmk failed to affect formation of autophagic vacuoles or partially prevented SDT-induced cytotoxicity, which suggested that SDT-induced autophagy functioned as a survival mechanism. Additionally, this study reported apparent apoptosis and autophagy with dependence on intracellular reactive oxygen species (ROS) production. Preliminary data showed that ROS scavenger N-acetylcysteine (NAC) effectively blocked the SDT induced accumulation of ROS, reversed sono-damage, cell apoptosis and autophagy. Taken together, these data indicate that autophagy may be cytoprotective in our experimental system, and the ROS caused by PpIX-SDT treatment may play an important role in initiating apoptosis and autophagy. PMID:25578562

  16. Blockage of Autophagy Rescues the Dual PI3K/mTOR Inhibitor BEZ235-induced Growth Inhibition of Colorectal Cancer Cells

    PubMed Central

    Oh, Iljoong; Cho, Hyunchul; Lee, Yonghoon; Cheon, Minseok; Park, Deokbae; Lee, Youngki

    2016-01-01

    Molecular targeting for the altered signaling pathways has been proven to be effective for the treatment ofmany types of human cancer, including colorectal cancer (CRC). The dual phosphatidylinositol-3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitor BEZ235 has shown to exhibit potent antitumor activity against solid tumors. Autophagy is a cellular lysosomal catabolic process to maintain metabolic homeostasis, which has been known to be induced in response to many therapeutic agents in cancer cells. This process is negatively regulated by mTOR and often acts as prosurvival or prodeath mechanism following cancer therapeutics. The current study was designed to investigate the antiproliferation activity of BEZ235 and to evaluate the role of autophagy induced by BEZ235 using HCT15 CRC cells bearing ras oncogene mutation. We found that BEZ235 decreases cell viability, which was mostly dependent on G1 arrest of cell cycle via suppression of cyclin A expression. BEZ235 affects PI3K/Akt/mTOR signaling pathway by increasing the phosphorylation of AKT at Ser473 and RAS/RAF/MEK/ERK pathway by decreasing the phosphorylation of ERK at Tyr204. BEZ235 also stimulated autophagy induction as evidenced by the increased expression of LC3-II and abundant acidic vesicular organelles (AVOs) in the cytoplasm. In addition, the combination of BEZ235 with autophagy inhibitor chloroquine, a known antagonist of autophagy, counteracted the antiproliferation effect of BEZ235. Thus, our study indicates that autophagy induced in response to BEZ235 treatment appears to act as cell death mechanism in HCT15 CRC cells. PMID:27294206

  17. Wavelet extractor: A Bayesian well-tie and wavelet extraction program

    NASA Astrophysics Data System (ADS)

    Gunning, James; Glinsky, Michael E.

    2006-06-01

    We introduce a new open-source toolkit for the well-tie or wavelet extraction problem of estimating seismic wavelets from seismic data, time-to-depth information, and well-log suites. The wavelet extraction model is formulated as a Bayesian inverse problem, and the software will simultaneously estimate wavelet coefficients, other parameters associated with uncertainty in the time-to-depth mapping, positioning errors in the seismic imaging, and useful amplitude-variation-with-offset (AVO) related parameters in multi-stack extractions. It is capable of multi-well, multi-stack extractions, and uses continuous seismic data-cube interpolation to cope with the problem of arbitrary well paths. Velocity constraints in the form of checkshot data, interpreted markers, and sonic logs are integrated in a natural way. The Bayesian formulation allows computation of full posterior uncertainties of the model parameters, and the important problem of the uncertain wavelet span is addressed uses a multi-model posterior developed from Bayesian model selection theory. The wavelet extraction tool is distributed as part of the Delivery seismic inversion toolkit. A simple log and seismic viewing tool is included in the distribution. The code is written in Java, and thus platform independent, but the Seismic Unix (SU) data model makes the inversion particularly suited to Unix/Linux environments. It is a natural companion piece of software to Delivery, having the capacity to produce maximum likelihood wavelet and noise estimates, but will also be of significant utility to practitioners wanting to produce wavelet estimates for other inversion codes or purposes. The generation of full parameter uncertainties is a crucial function for workers wishing to investigate questions of wavelet stability before proceeding to more advanced inversion studies.

  18. Pore Structure and Petrophysical Characterization of Hamelin Pool Stromatolites, Shark Bay, Western Australia

    NASA Astrophysics Data System (ADS)

    Karaca, E.; Eberli, G. P.; Weger, R. J.; Parke, E.

    2014-12-01

    Stromatolites are organic-sedimentary structures that form by trapping and binding of sediments and calcium carbonate precipitation through microbial activity. The largest modern stromatolite province is the hypersaline Hamelin Pool, Western Australia. Microbial precipitation generates a rigid framework with a wide range of porosities and pore sizes that influence the ultrasonic velocity permeability and resistivity in stromatolites. Stromatolites generally have simple and large pore structures and an impressive high permeability values. In the 55 core plugs, permeability varies from 0.5 D to 9 D, while porosity ranges from 17% to 46%. Ultrasonic velocity, measured under dry and saturated conditions, is generally high with a large scatter at any given porosity. Likewise large variations of porosity exist at any given velocity. For example, at 29% porosity, (dry) velocity ranges from 3611m/s to 5384m/s. Similarly at a velocity of 4048m/s the porosity ranges from 23% to 46%. Digital image analysis indicates that the main control on the variations is the pore complexity and size. Larger pores produce faster velocities at equal porosity. In saturated plugs compressional velocities increase up to 365m/s. In contrast, shear velocities show both a decrease (up to 578m/s) and an increase (up to 391m/s) in shear velocity (vs) with saturation. These changes in vsindicate that the stromatolites do change the shear modulus with saturation, thus violating the assumption by Gassmann. The cementation factor "m" (from Archie's equation, F = φ-m) determined from electrical resistivity varies in a narrow range from 2.1 to 2.6. This narrow range reduces the uncertainty in predicting the hydrocarbon/water saturation in stromatolites. The large range of porosities at a given velocity, however, makes porosity estimates from seismic inversion a challenge and, similarly, the shear moduli changes and the resultant shear strengthening and weakening add uncertainties to AVO analysis in

  19. Surface-inspired molecular vanadium oxide catalysts for the oxidative dehydrogenation of alcohols: evidence for metal cooperation and peroxide intermediates.

    PubMed

    Werncke, C Gunnar; Limberg, Christian; Knispel, Christina; Mebs, Stefan

    2011-10-17

    On the basis that thiacalix[4]arene (H(4)T4A) complex (PPh(4) )(2) [H(2)T4A(VO(2))](2) (Ia) was found to be an adequate functional model for surface species occurring on vanadium oxide based catalysts and itself catalyses the oxidative dehydrogenation (ODH) of alcohols, an analogue containing 2,2'-thiobis(2,4-di-tert-butylphenolate), (S)L(2-), as ligand, namely, (PPh(4))(2)[(S)LVO(2)](2) (II) was investigated in the same context. Despite the apparent similarity of Ia and II, studies on II revealed several novel insights, which are also valuable in connection with surfaces of vanadia catalysts: 1) For Ia and II similar turnover numbers (TONs) were found for the ODH of activated alcohols, which indicates that the additional OH units inherent to Ia do not contribute particularly to the activity of this complex, for instance, through prebinding of the alcohol. 2) On dissolution II enters into an equilibrium with a monomeric form, which is the predominant species in solution; nevertheless, ODH proceeds exclusively at the dimeric form, and this stresses the need for cooperation of two vanadium centres. 3) By omitting O(2) from the system during the oxidation of 9-fluorenol, the reduced form of the catalyst could be isolated and fully characterised (including single-crystal X-ray analysis). The corresponding intermediate had been elusive in case of thiacalixarene system Ia. 4) Reoxidation was found to proceed via a peroxide intermediate that also oxidises one alcohol equivalent. As the peroxide can also perform mono- and dioxygenation of the thioether group in II, after a number of turnovers the active catalyst contains a sulfone group. The reduced form of this ultimate catalyst was also isolated and structurally characterised. Possible implications of 1)-4) for the function of heterogeneous vanadia catalysts are discussed. PMID:21915928

  20. Highly-optimized TWSM software package for seismic diffraction modeling adapted for GPU-cluster

    NASA Astrophysics Data System (ADS)

    Zyatkov, Nikolay; Ayzenberg, Alena; Aizenberg, Arkady

    2015-04-01

    Oil producing companies concern to increase resolution capability of seismic data for complex oil-and-gas bearing deposits connected with salt domes, basalt traps, reefs, lenses, etc. Known methods of seismic wave theory define shape of hydrocarbon accumulation with nonsufficient resolution, since they do not account for multiple diffractions explicitly. We elaborate alternative seismic wave theory in terms of operators of propagation in layers and reflection-transmission at curved interfaces. Approximation of this theory is realized in the seismic frequency range as the Tip-Wave Superposition Method (TWSM). TWSM based on the operator theory allows to evaluate of wavefield in bounded domains/layers with geometrical shadow zones (in nature it can be: salt domes, basalt traps, reefs, lenses, etc.) accounting for so-called cascade diffraction. Cascade diffraction includes edge waves from sharp edges, creeping waves near concave parts of interfaces, waves of the whispering galleries near convex parts of interfaces, etc. The basic algorithm of TWSM package is based on multiplication of large-size matrices (make hundreds of terabytes in size). We use advanced information technologies for effective realization of numerical procedures of the TWSM. In particular, we actively use NVIDIA CUDA technology and GPU accelerators allowing to significantly improve the performance of the TWSM software package, that is important in using it for direct and inverse problems. The accuracy, stability and efficiency of the algorithm are justified by numerical examples with curved interfaces. TWSM package and its separate components can be used in different modeling tasks such as planning of acquisition systems, physical interpretation of laboratory modeling, modeling of individual waves of different types and in some inverse tasks such as imaging in case of laterally inhomogeneous overburden, AVO inversion.

  1. Autophagy-related Gene 7 (ATG7) and Reactive Oxygen Species/Extracellular Signal-regulated Kinase Regulate Tetrandrine-induced Autophagy in Human Hepatocellular Carcinoma*

    PubMed Central

    Gong, Ke; Chen, Chao; Zhan, Yao; Chen, Yan; Huang, Zebo; Li, Wenhua

    2012-01-01

    Tetrandrine, a bisbenzylisoquinoline alkaloid isolated from the broadly used Chinese medicinal herb Stephaniae tetrandrae, exhibits potent antitumor effects and has the potential to be used as a cancer chemotherapeutic agent. We previously reported that high concentrations of tetrandrine induce apoptosis in liver cancer cells. Here, we found that in human hepatocellular carcinoma (HCC) cells, a low dose of tetrandrine (5 μm) induced the expression of LC3-II, resulted in the formation of acidic autophagolysosome vacuoles (AVOs), and caused a punctate fluorescence pattern with the GFP-LC3 protein, which all are markers for cellular autophagy. Tetrandrine induced the production of intracellular reactive oxygen species (ROS), and treatment with ROS scavengers significantly abrogated the tetrandrine-induced autophagy. These results suggest that the generation of ROS plays an important role in promoting tetrandrine-induced autophagy. Tetrandrine-induced mitochondrial dysfunction resulted in ROS accumulation and autophagy. ROS generation activated the ERK MAP kinase, and the ERK signaling pathway at least partially contributed to tetrandrine-induced autophagy in HCC cells. Moreover, we found that tetrandrine transcriptionally regulated the expression of autophagy related gene 7 (ATG7), which promoted tetrandrine-induced autophagy. In addition to in vitro studies, similar results were also observed in vivo, where tetrandrine caused the accumulation of ROS and induced cell autophagy in a tumor xenograft model. Interestingly, tetrandrine treatment also induced autophagy in a ROS-dependent manner in C. elegans muscle cells. Therefore, these findings suggest that tetrandrine is a potent autophagy agonist and may be a promising clinical chemotherapeutic agent. PMID:22927446

  2. Effect of argan and olive oil consumption on the hormonal profile of androgens among healthy adult Moroccan men.

    PubMed

    Derouiche, Abdelfettah; Jafri, Ali; Driouch, Issam; El Khasmi, Mohammed; Adlouni, Ahmed; Benajiba, Nada; Bamou, Youssef; Saile, Rachid; Benouhoud, Mohammed

    2013-01-01

    This study aimed to assess the effect of virgin argan oil (VAO) and extra virgin olive oil (EVO) on the hormonal profile of androgens and anthropometric parameters among healthy adult Moroccan men during a controlled nutritional intervention. The study was carried out on 60 young and healthy male volunteers aged between 23 and 40 years old. During a stabilization period of 2 weeks they consumed butter. The group was then randomized into two categories, the first one consuming VAO and the second EVO for 3 weeks. Testosterone (T), luteinizing hormone (LH) and dehydroepiandrosterone (DHEAS) serum concentrations were measured at the beginning of the study and at the end of each period. The Mann-Whitney test was used to compare the two groups (VAO and EVO) during each step of the study. Differences in androgens and anthropometric parameters between the baseline and after 3 weeks of the diet in the VAO and EVO groups were analyzed using the Wilcoxon test. T and LH serum concentrations significantly increased after the intervention period. T levels increased by 19.9% and 17.4% (p < 0.0001), and LH levels by 18.5% (p < 0.007) and 42.6% (p < 0.0001), respectively, for VAO and EVO (p < 0.0001). However, DHEAS serum concentrations, body weight, body mass index, arterial pressure and daily energetic intake did not show any significant variation after the intervention with either argan or olive oils. The results suggest that consumption of AVO and EVO might be the origin of a positive action on the androgen hormonal profile of men. PMID:23472458

  3. Complex seismic amplitude inversion for P-wave and S-wave quality factors

    NASA Astrophysics Data System (ADS)

    Zong, Zhaoyun; Yin, Xingyao; Wu, Guochen

    2015-07-01

    Stratum quality factors (P-wave and S-wave quality factors, Qp and Qs) have gradually been utilized in the study of physical state of crust and uppermost mantle, tectonic evolution, hydrogeololgy, gas hydrates, petroleum exploration, etc. Different opinions of the seismic attenuation mechanism result in various approaches to estimate the P-wave and S-wave quality factors. Considering the viscoelasticity of the underground medium, the constitutive matrix of the Earth medium is written as the superposition of homogeneous background medium, elastic perturbation medium and viscoelastic perturbation medium. Under the hypothesis of Born integral and stationary phase approximation, the seismic reflectivity is initially raised in terms of P-wave and S-wave moduli, density, P-wave and S-wave quality factors. Furthermore, incorporating the complex seismic traces with the seismic wavelets at different offsets, a two-step inversion approach is proposed to estimate the P-wave and S-wave quality factors. The AVO/AVA Bayesian inversion approach is suggested to estimate the P-wave modulus and S-wave modulus with the real component of the pre-stack seismic data initially. Taking the estimated P-wave and S-wave moduli as prior information, the P-wave and S-wave quality factors are further estimated with the imaginary component of the complex pre-stack seismic data, which is the quadrature of the original data. Finally, synthetic examples demonstrate that the proposed approach is able to estimate P-wave and S-wave quality factors stably and properly, and two field data examples demonstrate that the proposed approach may work as an efficient approach to fluid identification.

  4. Eruption Forecasting in Alaska: A Retrospective and Test of the Distal VT Model

    NASA Astrophysics Data System (ADS)

    Prejean, S. G.; Pesicek, J. D.; Wellik, J.; Cameron, C.; White, R. A.; McCausland, W. A.; Buurman, H.

    2015-12-01

    United States volcano observatories have successfully forecast most significant US eruptions in the past decade. However, eruptions of some volcanoes remain stubbornly difficult to forecast effectively using seismic data alone. The Alaska Volcano Observatory (AVO) has responded to 28 eruptions from 10 volcanoes since 2005. Eruptions that were not forecast include those of frequently active volcanoes with basaltic-andesite magmas, like Pavlof, Veniaminof, and Okmok volcanoes. In this study we quantify the success rate of eruption forecasting in Alaska and explore common characteristics of eruptions not forecast. In an effort to improve future forecasts, we re-examine seismic data from eruptions and known intrusive episodes in Alaska to test the effectiveness of the distal VT model commonly employed by the USGS-USAID Volcano Disaster Assistance Program (VDAP). In the distal VT model, anomalous brittle failure or volcano-tectonic (VT) earthquake swarms in the shallow crust surrounding the volcano occur as a secondary response to crustal strain induced by magma intrusion. Because the Aleutian volcanic arc is among the most seismically active regions on Earth, distinguishing distal VT earthquake swarms for eruption forecasting purposes from tectonic seismicity unrelated to volcanic processes poses a distinct challenge. In this study, we use a modified beta-statistic to identify pre-eruptive distal VT swarms and establish their statistical significance with respect to long-term background seismicity. This analysis allows us to explore the general applicability of the distal VT model and quantify the likelihood of encountering false positives in eruption forecasting using this model alone.

  5. Inhibition of autophagy enhances DNA damage-induced apoptosis by disrupting CHK1-dependent S phase arrest

    SciTech Connect

    Liou, Jong-Shian; Wu, Yi-Chen; Yen, Wen-Yen; Tang, Yu-Shuan; Kakadiya, Rajesh B.; Su, Tsann-Long; Yih, Ling-Huei

    2014-08-01

    DNA damage has been shown to induce autophagy, but the role of autophagy in the DNA damage response and cell fate is not fully understood. BO-1012, a bifunctional alkylating derivative of 3a-aza-cyclopenta[a]indene, is a potent DNA interstrand cross-linking agent with anticancer activity. In this study, BO-1012 was found to reduce DNA synthesis, inhibit S phase progression, and induce phosphorylation of histone H2AX on serine 139 (γH2AX) exclusively in S phase cells. Both CHK1 and CHK2 were phosphorylated in response to BO-1012 treatment, but only depletion of CHK1, but not CHK2, impaired BO-1012-induced S phase arrest and facilitated the entry of γH2AX-positive cells into G2 phase. CHK1 depletion also significantly enhanced BO-1012-induced cell death and apoptosis. These results indicate that BO-1012-induced S phase arrest is a CHK1-dependent pro-survival response. BO-1012 also resulted in marked induction of acidic vesicular organelle (AVO) formation and microtubule-associated protein 1 light chain 3 (LC3) processing and redistribution, features characteristic of autophagy. Depletion of ATG7 or co-treatment of cells with BO-1012 and either 3-methyladenine or bafilomycin A1, two inhibitors of autophagy, not only reduced CHK1 phosphorylation and disrupted S phase arrest, but also increased cleavage of caspase-9 and PARP, and cell death. These results suggest that cells initiate S phase arrest and autophagy as pro-survival responses to BO-1012-induced DNA damage, and that suppression of autophagy enhances BO-1012-induced apoptosis via disruption of CHK1-dependent S phase arrest. - Highlights: • Autophagy inhibitors enhanced the cytotoxicity of a DNA alkylating agent, BO-1012. • BO-1012-induced S phase arrest was a CHK1-dependent pro-survival response. • Autophagy inhibition enhanced BO-1012 cytotoxicity via disrupting the S phase arrest.

  6. Gas Hydrate Deposits in the Cauvery-Mannar Offshore Basin, India

    NASA Astrophysics Data System (ADS)

    Dewangan, P.

    2015-12-01

    The analysis of geophysical and coring data from Mahanadi and Krishna-Godavari offshore basins, eastern continental margin of India, has established the presence of gas hydrate deposits; however, other promising petroliferous basins are relatively unexplored for gas hydrates. A collaborative program between GSI/MoM and CSIR-NIO was formulated to explore the Cauvery-Mannar offshore basin for gas hydrate deposits (Fig. 1a). High quality multi-channel reflection seismics (MCS) data were acquired with 3,000 cu. in airgun source array and 3 km long hydrophone streamer (240 channels) onboard R/V Samudra Ratnakar for gas hydrate studies. Other geophysical data such as gravity, magnetic and multibeam data were also acquired along with seismic data.After routine processing of seismic data, the bottom simulating reflectors (BSRs) are observed in the central and north-eastern part of the survey area. The BSRs are identified based on its characteristic features such as mimicking the seafloor, opposite polarity with respect to the seafloor and crosscutting the existing geological layers (Fig. 1b). At several locations, seismic signatures associated with free gas such as drop in interval velocity, pull-down structures, amplitude variation with offset (AVO) and attenuation are observed below the BSRs which confirm the presence of free gas in the study area. Acoustic chimneys are observed at some locations indicating vertical migration of the free gas. The observed seismic signatures established the presence of gas hydrates/free gas deposits in Cauvery-Mannar basin. Interestingly, BSRs appear to be distributed along the flanks of submarine canyon indicating the influence of geomorphology on the formation and distribution of gas hydrates.

  7. Age and cardiac output during cycle exercise in thermoneutral and warm environments.

    PubMed

    Minson, C T; Kenney, W L

    1997-01-01

    To determine whether chronological age, independent of changes in aerobic capacity, alters cardiac output (Qc), the central hemodynamic responses to intermittent incremental cycle exercise were studied in two groups of men. Qc was measured at rest and during exercise at 35%, 60%, 75%, and 85% peak aerobic capacity (VO2peak) using a CO2 rebreathing method in seven trained older (65 +/- 2 yr) and eight normally active but untrained young men (26 +/- 1 yr) matched for VO2peak and anthropometric measures. Subjects were tested in both a thermoneutral (22 degrees C) and a warm (36 degrees C) environment to investigate possible differential cardiovascular responses to exercise in the heat. Only subjects with no history of pulmonary, cardiac, neuromuscular, or endocrine disease and a normal electrocardiogram were studied. The older men had significantly lower (P < 0.05) Qc relative to the younger men at intensities greater than 60% VO2peak in both environmental conditions. At these higher intensities, the older men had a significantly higher stroke volume (SV) and lower heart rate (HR) (P < 0.05). A higher arteriovenous oxygen difference ((a-v)O2)) compared with their younger counterparts enabled the older men to exercise at the same absolute intensity, most likely because of training induced changes in left-ventricular performance and oxygen extraction. The addition of an exogenous heat source did not alter the Qc response in either group of men; however, a higher HR (P < 0.05) and smaller SV (P > 0.05) were observed in the young men during exercise in the heat. This may reflect previously reported differences in the skin blood flow response of VO2peak-matched young and older men during exercise. It is suggested that endurance trained older men can enhance left-ventricular performance to augment SV, but not sufficiently to maintain Qc in light of an attenuated HR response during exercise at intensities above 60% VO2peak. PMID:9000158

  8. Iterative Multiparameter Elastic Waveform Inversion Using Prestack Time Imaging and Kirchhoff approximation

    NASA Astrophysics Data System (ADS)

    Khaniani, Hassan

    This thesis proposes a "standard strategy" for iterative inversion of elastic properties from the seismic reflection data. The term "standard" refers to the current hands-on commercial techniques that are used for the seismic imaging and inverse problem. The method is established to reduce the computation time associated with elastic Full Waveform Inversion (FWI) methods. It makes use of AVO analysis, prestack time migration and corresponding forward modeling in an iterative scheme. The main objective is to describe the iterative inversion procedure used in seismic reflection data using simplified mathematical expression and their numerical applications. The frame work of the inversion is similar to (FWI) method but with less computational costs. The reduction of computational costs depends on the data conditioning (with or without multiple data), the level of the complexity of geological model and acquisition condition such as Signal to Noise Ratio (SNR). Many processing methods consider multiple events as noise and remove it from the data. This is the motivation for reducing the computational cost associated with Finite Difference Time Domain (FDTD) forward modeling and Reverse Time Migration (RTM)-based techniques. Therefore, a one-way solution of the wave equation for inversion is implemented. While less computationally intensive depth imaging methods are available by iterative coupling of ray theory and the Born approximation, it is shown that we can further reduce the cost of inversion by dropping the cost of ray tracing for traveltime estimation in a way similar to standard Prestack Time Migration (PSTM) and the corresponding forward modeling. This requires the model to have smooth lateral variations in elastic properties, so that the traveltime of the scatterpoints can be approximated by a Double Square Root (DSR) equation. To represent a more realistic and stable solution of the inverse problem, while considering the phase of supercritical angles, the

  9. A Trial of the Delineation of Gas Hydrate Bearing Zones using Seismic Methods Offshore Tokai Japan

    NASA Astrophysics Data System (ADS)

    Inamori, T.; Hato, M.

    2002-12-01

    . JNOC, Japan National Oil Corporation, and METI conducted three 3D seismic surveys at offshore Tokai Japan in 2002 and they will drilled some research well at the same area from 2003 to 2004. We hope to image 3D gas hydrate bearing layers from the 3D seismic data and well results. To image the gas hydrate bearing zones, we will try to detect interval velocities from seismic data and to resolve much higher, we are planning to execute the multi-seismic attribute analysis and AVO inversion.

  10. Estimation of Physical Property Changes by Oil Saturation in Carbonates and Sandstone Using Computational Rock Physics Methods

    NASA Astrophysics Data System (ADS)

    Lee, M.; Keehm, Y.

    2010-12-01

    Carbonate Reservoirs are drawing a great attention as global energy demands and consumption increase rapidly, since more than 60% of oil and 40% of gas of world reserves are in carbonate rocks. However, most of them are hard to develop mainly due to their complexity and heterogeneity, especially at the pore scale. In this study, we perform computational rock physics modeling (numerical simulations on pore microstructures of carbonate rocks) and compare the results with those from sandstone. The brief procedure of the method is (1) to obtain high-resolution pore microstructure with a spatial resolution of 1-2 micron by X-ray microtomography technique, (2) to perform two-phase lattice-Boltzmann (LB) flow simulation to obtain various oil and water saturations, then (3) to calculate physical properties, such as P-wave velocity and electrical conductivity through pore-scale property simulation techniques. For the carbonate rock, we identified much more isolated pores than sandstone by investigating pore microstructures. Thus permeability and electrical conductivity were much smaller than those of sandstone. The electrical conductivity versus oil saturation curve of the carbonate rock showed sharper decrease at low oil saturation, but similar slope at higher oil saturation. We think that higher complexity of pore connectivity is responsible for this effect. The P-wave velocity of the carbonate rock was much higher than sandstone and the it did not show any significant changes during the change of oil saturation. Therefore, we think that fluid discrimination by seismic data with P-wave velocity alone would pose a greate challenge in most carbonate reservoirs. In addition, the S-wave velocity seems not to be sensitive either, which suggest that the AVO-type analysis would also be difficult, though requires more researches. On the other hand, our computational rock physics approach can be useful in preliminary analysis of carbonate reservoirs since it can determine the

  11. Ash Emissions and Risk Management in the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Steensen, T. S.; Webley, P. W.; Stuefer, M.

    2012-12-01

    Located in the 'Ring of Fire', regions and communities around the Pacific Ocean often face volcanic eruptions and subsequent ash emissions. Volcanic ash clouds pose a significant risk to aviation, especially in the highly-frequented flight corridors around active volcano zones like Indonesia or Eastern Russia and the Alaskan Aleutian Islands. To mitigate and manage such events, a detailed quantitative analysis using a range of scientific measurements, including satellite data and Volcanic Ash Transport and Dispersion (VATD) model results, needs to be conducted in real-time. For the case study of the Sarychev Peak eruption in Russia's Kurile Islands during 2009, we compare ash loading and dispersion from Weather Research and Forecast model with online Chemistry (WRF-Chem) results with satellite data of the eruption. These parameters are needed for the real-time management of volcanic crises to outline no-fly zones and to predict the areas that the ash is most likely to reach in the near future. In the early stages after the eruption, an international group with representatives from the Kamchatkan and Sachalin Volcanic Eruption Response Teams (KVERT, SVERT), the National Aeronautics and Space Administration (NASA), and the Alaska Volcano Observatory (AVO) published early research on the geological and geophysical characteristics of the eruption and the behavior of the resulting ash clouds. The study presented here is a follow-up project aimed to implement VATD model results and satellite data retrospectively to demonstrate the possibilities to develop this approach in real-time for future eruptions. Our research finds that, although meteorological cloud coverage is high in those geographical regions and, consequently, these clouds can cover most of the ash clouds and as such prevent satellites from detecting it, both approaches compare well and supplement each other to reduce the risk of volcanic eruptions. We carry out spatial extent and absolute quantitative

  12. Processing, inversion, and interpretation of 9C-3D seismic data for characterizing the Morrow A sandstone, Postle Field, Oklahoma

    NASA Astrophysics Data System (ADS)

    Singh, Paritosh

    Detection of Morrow A sandstones is a major problem in the exploration of new fields and the characterization of existing fields because they are very thin and laterally discontinuous. The present research shows the advantages of S-wave data in detecting and characterizing the Morrow A sandstone. Full-waveform modeling is done to understand the sandstone signature in P-, PS- and S-wave gathers. The sandstone shows a distinct high-amplitude event in pure S-wave reflections as compared to the weaker P- and PS-wave events. Modeling also helps in understanding the effect of changing sandstone thickness, interbed multiples (generated by shallow high-velocity anhydrite layers) and sidelobe interference effect (due to Morrow shale) at the Morrow A level. Multicomponent data need proper care while processing, especially the S-wave data which are aected by the near-surface complexity. Cross-spread geometry and 3D FK filtering are effective in removing the low-velocity noise trends. The S-wave data obtained after stripping the S-wave splitting in the overburden show improvement for imaging and reservoir property determination. Individual P- and S-wave attributes as well as their combinations have been analyzed to predict the A sandstone thickness. A multi-attribute map and collocated cokriging procedure is used to derive the seismic-guided isopach of the A sandstone. Postle Field is undergoing CO2 flooding and it is important to understand the characteristics of the reservoir for successful flood management. Density can play an important role in finding and monitoring high-quality reservoirs, and to predict reservoir porosity. prestack P- and S-wave AVO inversion and joint P- and S-wave inversion provide density estimates along with the P- and S-impedance for better characterization of the Morrow A sandstone. The research provides a detailed multicomponent processing, inversion and interpretation work flow for reservoir characterization, which can be used for exploration in

  13. The Distribution and Movement of Volcanic Ash and SO2 Observed in Satellite Data from the Eruption of Augustine Volcano, 2006

    NASA Astrophysics Data System (ADS)

    Dean, K. G.; Dehn, J.; Wallace, K. L.; Prata, F.; Cahill, C. F.

    2006-12-01

    the 1.15-2.5 micron size fraction. The concentration of SO2 could not be measured since no instruments were deployed. The satellite data and observations presented here were contributed by an AVO team from the University of Alaska Fairbanks and USGS that currently includes 5 students, 2 staff and 8 scientists.

  14. Gas Hydrate and Pore Pressure

    NASA Astrophysics Data System (ADS)

    Tinivella, Umberta; Giustiniani, Michela

    2014-05-01

    Many efforts have been devoted to quantify excess pore pressures related to gas hydrate dissociation in marine sediments below the BSR using several approaches. Dissociation of gas hydrates in proximity of the BSR, in response to a change in the physical environment (i.e., temperature and/or pressure regime), can liberate excess gas incrising the local pore fluid pressure in the sediment, so decreasing the effective normal stress. So, gas hydrate dissociation may lead to excess pore pressure resulting in sediment deformation or failure, such as submarine landslides, sediment slumping, pockmarks and mud volcanoes, soft-sediment deformation and giant hummocks. Moreover, excess pore pressure may be the result of gas hydrate dissociation due to continuous sedimentation, tectonic uplift, sea level fall, heating or inhibitor injection. In order to detect the presence of the overpressure below the BSR, we propose two approachs. The fist approach models the BSR depth versus pore pressure; in fact, if the free gas below the BSR is in overpressure condition, the base of the gas hydrate stability is deeper with respect to the hydrostatic case. This effect causes a discrepancy between seismic and theoretical BSR depths. The second approach models the velocities versus gas hydrate and free gas concentrations and pore pressure, considering the approximation of the Biot theory in case of low frequency, i.e. seismic frequency. Knowing the P and S seismic velocity from seismic data analysis, it is possibile to jointly estimate the gas hydrate and free gas concentrations and the pore pressure regime. Alternatively, if the S-wave velocity is not availbale (due to lack of OBS/OBC data), an AVO analysis can be performed in order to extract information about Poisson ratio. Our modeling suggests that the areas characterized by shallow waters (i.e., areas in which human infrastructures, such as pipelines, are present) are significantly affected by the presence of overpressure condition

  15. The Unconventional Revolution in Exploration Geophysics

    NASA Astrophysics Data System (ADS)

    House, N. J.

    2014-12-01

    During the last 25 years, 3D seismic imaging has revolutionized hydrocarbon exploration by delivering an accurate 3 dimensional picture of the subsurface. The image is capable of detecting fluids within the reservoir, and has significantly reduced the risk of locating and developing hydrocarbon deposits. In late 1990s, deregulation of natural gas prices allowed long recognized deposits of natural gas locked in tight rocks be economic. It sparked factory drilling (repeatable high density evenly spaced) wells and hydraulic fracturing that would help unlock the reservoirs. All that was needed was a geologist to determine depths and limits of the reservoir and engineers to drill and complete the wells. If 3D seismic data was available, it might have been used to define both the limits of the field and drilling hazards. Generally the cost and time required to process and interpret 3D Seismic was considered too high to affect the perceived geologic risk of the Factory approach. Completion costs in unconventional reservoirs account for over 50% of the well costs. It's therefore critical to understand the geometry of how the rock is fracturing and determine optimum well spacing to balance the cost of development with the value of the gas or oil being produced. By extending AVO to the pre-stack domain, it's possible to simultaneously invert for Vp, Vs and density. Armed with these three fundamental rock properties that dictate elastic and inelastic rock response, researchers were able to combine those properties to tie directly to how well a rock will respond to hydraulic fracturing, or which rocks contain a higher TOC, or other rock properties that control how a rock responds to seismic waves or hydraulic fracturing. Combining these results allows interpreters to map areas of higher productivity, and identify bypassed reserves. Currently hundreds of different seismic attributes that are generated from 3D seismic data are used to identify the highest productive areas and

  16. Integrating sequence stratigraphy and seismic attributes for quantitative reservoir characterization: A case study of a Pliocene reservoir, Campeche Sound, Mexico

    NASA Astrophysics Data System (ADS)

    Mendez-Hernandez, Efrain

    An integrated workflow including analysis of seismic, core, well log and biostratigraphic data was developed and conducted to both construct a reliable geologic model and characterize a Pliocene gas reservoir which overlies the Cantarell field in the Campeche Sound, southern Gulf of Mexico. In 2003, the offshore exploratory Utan #1 well was drilled to investigate the gas potential of the Pliocene sequence. The well provided successful results from facies characterized by thin mixed siliciclastic-carbonate beds contained within a faulted rollover anticline. Campeche Sound is the most prolific Mexican oil producing province where the best fields are Mesozoic-Paleocene carbonates in structural traps. Therefore, little exploration has been focused on the overlying late Tertiary and more siliciclastic section, representing a gap in the knowledge of this part of the basin where new expectations arise for non-associated gas entrapments in a traditionally oil-producing province. Based upon development of a sequence stratigraphic framework, a new play analysis is developed where the reservoirs are identified as retrogradational shoreface parasequences sitting atop third-order sequence boundaries. Basic and advanced seismic attributes contribute to the stratigraphic interpretation and gas detection. Seismic inversion for reflectivity allowed better identification of key stratigraphic surfaces. Modeled Type-I AVO and a dimmed spectral decomposition response following structural contours provide reliability to gas discrimination and reservoir delineation. The seismic attributes will require additional support to be valuable as reservoir quality predictors. Because biogenic methane and thin sheet reservoirs define the rock-fluid system, development may be uneconomic. However, the trapped gas could be reinjected at deeper depths to improve recovery efficiency of oil in the Cantarell field. The knowledge gained from this research is an important contribution to the petroleum

  17. Amplitude inversion of fast and slow converted waves for fracture characterization of the Montney Formation in Pouce Coupe field, Alberta, Canada

    NASA Astrophysics Data System (ADS)

    MacFarlane, Tyler L.

    The Montney Formation of western Canada is one of the largest economically viable gas resource plays in North America with reserves of 449TCF. As an unconventional tight gas play, the well development costs are high due to the hydraulic stimulations necessary for economic success. The Pouce Coupe research project is a multidisciplinary collaboration between the Reservoir Characterization Project (RCP) and Talisman Energy Inc. with the objective of understanding the reservoir to enable the optimization of well placement and completion design. The work in this thesis focuses on identifying the natural fractures in the reservoir that act as the delivery systems for hydrocarbon flow to the wellbore. Characterization of the Montney Formation at Pouce Coupe is based on time-lapse multicomponent seismic surveys that were acquired before and after the hydraulic stimulation of two horizontal wells. Since shear-wave velocities and amplitudes of the PS-waves are known to be sensitive to near-vertical fractures, I utilize isotropic simultaneous seismic inversions on azimuthally-sectored PS1 and PS2 data sets to obtain measurements of the fast and slow shear-velocities. Specifically, I analyze two orthogonal azimuths that are parallel and perpendicular to the strike of the dominant fracture system in the field. These volumes are used to approximate the shear-wave splitting parameter (gamma(s*)) that is closely related to crack density. Since crack density has a significant impact on defining the percolation zone, the work presented in this thesis provides information that can be utilized to reduce uncertainty in the reservoirs fracture model. Isotropic AVO inversion of azimuthally limited PS-waves demonstrates sufficient sensitivity to detect contrast between the anisotropic elastic properties of the reservoir and is capable of identifying regions with high crack density. This is supported by integration with spinner production logs, hydraulic stimulation history of the field

  18. Integration of seismic methods with reservoir simulation, Pikes Peak heavy oil field, Saskatchewan

    NASA Astrophysics Data System (ADS)

    Zou, Ying

    temperature changes (˜8 m in a year) based on the reservoir simulation results. The pressure dependence of the seismic data is due to its influences on gas saturation. The bypassed oil area and steam fronts (high temperature front) can be estimated from the temperature and oil saturation distributions from the reservoir simulation. AVO results show a steam and gas zone pattern similar to the one produced by reservoir simulation.

  19. High Resolution/High Fidelity Seismic Imaging and Parameter Estimation for Geological Structure and Material Characterization

    SciTech Connect

    Ru-Shan Wu, Xiao-Bi Xie, Thorne Lay

    2005-06-06

    In this project, we develop new theories and methods for multi-domain one-way wave-equation based propagators, and apply these techniques to seismic modeling, seismic imaging, seismic illumination and model parameter estimation in 3D complex environments. The major progress of this project includes: (1) The development of the dual-domain wave propagators. We continue to improve the one-way wave-equation based propagators. Our target is making propagators capable of handling more realistic velocity models. A wide-angle propagator for transversely isotropic media with vertically symmetric axis (VTI) has been developed for P-wave modeling and imaging. The resulting propagator is accurate for large velocity perturbations and wide propagation angles. The thin-slab propagator for one-way elastic-wave propagation is further improved. With the introduction of complex velocities, the quality factors Qp and Qs have been incorporated into the thin-slab propagator. The resulting viscoelastic thin-slab propagator can handle elastic-wave propagation in models with intrinsic attenuations. We apply this method to complex models for AVO modeling, random media characterization and frequency-dependent reflectivity simulation. (2) Exploring the Information in the Local Angle Domain. Traditionally, the local angle information can only be extracted using the ray-based method. We develop a wave-equation based technique to process the local angle domain information. The approach can avoid the singularity problem usually linked to the high-frequency asymptotic method. We successfully apply this technique to seismic illumination and the resulting method provides a practical tool for three-dimensional full-volume illumination analysis in complex structures. The directional illumination also provides information for angle-domain imaging corrections. (3) Elastic-Wave Imaging. We develop a multicomponent elastic migration method. The application of the multicomponent one-way elastic propagator

  20. NON-INVASIVE DETERMINATION OF THE LOCATION AND DISTRIBUTION OF FREE-PHASE DENSE NONAQUEOUS PHASE LIQUIDS (DNAPL) BY SEISMIC REFLECTION TECHNIQUES

    SciTech Connect

    Michael G. Waddell; William J. Domoracki; Tom J. Temples

    2001-05-01

    This semi-annual technical progress report is for Task 4 site evaluation, Task 5 seismic reflection design and acquisition, and Task 6 seismic reflection processing and interpretation on DOE contact number DE-AR26-98FT40369. The project had planned one additional deployment to another site other than Savannah River Site (SRS) or DOE Hanford. During this reporting period the project had an ASME peer review. The findings and recommendation of the review panel, as well at the project team response to comments, are in Appendix A. After the SUBCON midyear review in Albuquerque, NM and the peer review it was decided that two additional deployments would be performed. The first deployment is to test the feasibility of using non-invasive seismic reflection and AVO analysis as monitoring to assist in determining the effectiveness of Dynamic Underground Stripping (DUS) in removal of DNAPL. Under the rescope of the project, Task 4 would be performed at the Charleston Navy Weapons Station, Charleston, SC and not at the Dynamic Underground Stripping (DUS) project at SRS. The project team had already completed Task 4 at the M-area seepage basin, only a few hundred yards away from the DUS site. Because the geology is the same, Task 4 was not necessary. However, a Vertical Seismic Profile (VSP) was conducted in one well to calibrate the geology to the seismic data. The first deployment to the DUS Site (Tasks 5 and 6) has been completed. Once the steam has been turned off these tasks will be performed again to compare the results to the pre-steam data. The results from the first deployment to the DUS site indicated a seismic amplitude anomaly at the location and depths of the known high concentrations of DNAPL. The deployment to another site with different geologic conditions was supposed to occur during this reporting period. The first site selected was DOE Paducah, Kentucky. After almost eight months of negotiation, site access was denied requiring the selection of another site

  1. Intermediate-Term Declines in Seismicity at Two Volcanoes in Alaska Following the Mw7.9 Denali Fault Earthquake

    NASA Astrophysics Data System (ADS)

    McNutt, S. R.; Sanchez, J. J.; Moran, S. C.; Power, J. A.

    2002-12-01

    The Mw7.9 Denali Fault earthquake provided an opportunity to look for intermediate-term (days to weeks) responses of Alaskan volcanoes to shaking from a large regional earthquake. The Alaska Volcano Observatory monitors 24 volcanoes with seismic networks. We examined one station for each volcano, generally the closest (typically 5 km from the vent) unless noise, site response, or other factors made the data unusable. Data were digitally bandpass filtered between 0.8 and 5 Hz to reduce noise from microseisms and wind. Data for the period three days before to three days after the Mw7.9 earthquake were then plotted at a standard scale used for AVO routine monitoring. Shishaldin volcano, which has a background rate of several hundred seismic events per day on station SSLS, showed no change from before to after the earthquake. Veniaminof volcano, which has had recent mild eruptions and a rate of several dozen seismic events per day on station VNNF, suffered a drop in seismicity at the time of the earthquake by a factor of 2.5; this lasted for 15 days. We tested this result using a different station, VNSS, and a different method of counting (non-filtered data on helicorder records) and found the same result. We infer that Veniaminof's activity was modified by the Mw7.9 earthquake. Wrangell, the closest volcano, had a background rate of about 10 events per day. Data from station WANC could not be measured for 8 days after the Mw7.9 earthquake because the large number of aftershocks precluded identification of local seismicity. For the following eight days, however, its seismicity rate was 30 percent lower than before. While subtle, we infer that this may be related to the earthquake. It is known that Wrangell increased its heat output after the Mw9.2 Alaska earthquake of 1964 and again after the Ms7.1 St. Elias earthquake of 1979. The other 21 volcanoes showed no changes in seismicity from 3 days before to 3 days after the Mw7.9 event. We conclude that intermediate

  2. Support Vector Machines for Non-linear Geophysical Inversion

    NASA Astrophysics Data System (ADS)

    Kuzma, H. A.; Rector, J. W.

    2004-12-01

    Classical non-linear geophysical inversion can be simulated using computer learning via Support Vector Machines. Geophysical inverse problems are almost always ill-posed which means that many different models (i.e. descriptions of the earth) can be found to explain a given noisy or incomplete data set. Regularization and constraints encourage inversions to find physically realistic models. The set of preferred models needs to be defined a priori using as much geologic knowledge as is available. In inversion, it is assumed that data and a forward modeling process is known. The goal is to solve for a model. In the SVM paradigm, a series of models and associated data are known. The goal is to solve for a reverse modeling process. Starting with a series of initial models assembled using all available geologic information, synthetic data is created using the most realistic forward modeling program available. With the synthetic data as inputs and the known models as outputs, a Support Vector Machine is trained to approximate a local inverse to the forward modeling program. The advantages of this approach are that it is honest about the need to establish, a priori, the kinds of models that are reasonable in a particular field situation. There is no need to adjust the forward process to accommodate inversion, because SVMs can be easily modified to capture complicated, non-linear relationships. SVMs are transparent and require very little programming. If an SVM is trained using model/data pairs that are drawn from the same probability distribution that is implicit in the regularization of an inversion, then it will get very similar results to the inversion. Because SVMs can interpret as much data as desired so long as the conditions of an experiment do not change, they can be used to perform otherwise computationally expensive procedures. Support Vector Machines are trained to emulate non-linear seismic Amplitude Variation with Offset (AVO) inversions, gravity inversions

  3. Support vector machines for geophysical inversion

    NASA Astrophysics Data System (ADS)

    Kuzma, Heidi Anderson

    (AVO) inversions. The SVMs tend to outperform linear inversion and match the results of non-linear inversion. Training an SVM, including generating training data, is generally much faster than performing a non-linear inversion.

  4. Overburden Pressure as a Cause of Vertical Velocity Gradient

    NASA Astrophysics Data System (ADS)

    Korneev, V. A.

    2012-12-01

    Nonlinear effect of rocks stressed by the overburden pressure causes anisotropy. Evaluation shows that such anisotropy can be significant, reaching several tens of percent and probably more. This result is consistent with common practices, when stacking velocity needs extra corrections with a changing offset. This also implies that at field scales all the rocks are likely to be anisotropic, and this property needs to be accounted for during migration of data, tomography, AVO analysis etc. The laboratory velocity measurements need to be corrected for the nonlinear overburden effects, when applied to the field scales. Nonlinear rock coefficients can be determined from the special laboratory measurements. They also can be evaluated from observation of the nonlinear propagation effects, such as multiple frequency generation. Nonlinear coefficient for Berea sandstone turned out to be by an order of magnitude larger than that estimated from borehole data. This is likely due to low stiffness and low fluid saturation of the used sample. This also suggests possibility of very high velocity gradient at shallow depths in some rocks. An assumption that the amplitudes of the static strains well exceed those related to the dynamic field is not critical. It was made in order to simplify the derivations. If both components are comparable, then the solution would have an additional nonlinear component representing a multiple harmonic. The relations between the nonlinear elastic constants and the elastic constants of the effective TI medium are very simple and allow straightforward estimate of the medium anisotropy induced by an applied stress. There are other causes of anisotropy in rocks besides an applied stress. The rock can possibly be anisotropic on a microscopic (clays) and mesoscopic (sedimentary layering) levels. The combined contribution of all the causes can either reduce or increase the overall effect. Same rock at different depths might have different wave propagation

  5. Status of EarthScope's Transportable Array in Alaska

    NASA Astrophysics Data System (ADS)

    Hafner, K.; Busby, R. W.; Enders, M.

    2014-12-01

    The EarthScope's Transportable Array has completed its first year of operations in Alaska. The proposed station grid uses 85 km spacing & consists of ~290 locations in Alaska and Western Canada. About 60 of the grid locations will be at existing seismic stations operated by the AEC, AVO & ATWC and are being upgraded with shallow borehole installations or higher quality sensors as appropriate. About 10 new stations will be collocated with PBO GPS stations. At the end of July 2014, 90% of the site reconnaissance has been completed, & 25 sites have been permitted with private landowners or the State of Alaska. 11 new TA stations have been installed, & 7 existing stations (AK network code) have been upgraded. Data from these stations is flowing to the Array Network Facility (ANF) and being archived at the IRIS DMC. As the Transportable Array has moved to Alaska, IRIS has experimented with different portable drills and drilling techniques to create shallow holes (1-5 m deep, 15-20 cm in diameter) in permafrost and rock outcrops for seismometer installation. The goal of these new methods is to maintain or enhance a station's noise performance while minimizing its footprint & the equipment, materials, and overall expense required for its construction. Motivating this approach are recent developments in posthole broadband seismometer design & the unique conditions for operating in Alaska, where most areas are only accessible by small plane or helicopter, & permafrost underlies much of the region. IRIS contracted with a drilling specialist to create a prototype Transportable Drill (less than 1300 lbs with tooling) that is capable of augering to 5 m in unconsolidated materials and permafrost, downhole hammering to 2.5 m in bedrock with a steel casing following the bit and diamond coring in solid rock to 2 m. This drill has been successfully deployed by helicopter to create a hole 2.7 m deep and 15 cm diameter in bedrock. The auger mode was used successfully to install a

  6. (S)TEM analysis of functional transition metal oxides

    NASA Astrophysics Data System (ADS)

    Chi, Miaofang

    Perovskite vanadates (AVO3) form an ideal family to study the structure-property relationships in transition metal oxides because their physical properties can easily be tailored by varying the A-site cations. (S)TEM is an ideal tool for this type of study due to its capacity for simultaneous imaging and chemical analysis. Determination of the oxidation state of vanadium in complex oxides have been carried out by electron energy loss spectroscopy. SrVO3/LaAlO3 is then studied both experimentally and theoretically as a prototype system. Extra electrons have been detected on the interface layer, and further proven to originate mainly from a change in the local bonding configuration of V at the La-O terminated substrate surface. Cr-containing stainless steel deposited with a LaCrO3 thin-film layer is a promising interconnect material of Solid Oxide Fuel Cells (SOFC). Our investigation on its microstructural evolution reveals that the LaCrO 3 thin film plays a role in inhibiting the growth of an oxide layer on the metal surface and thus protects the surface of the stainless steel. Ca-doped LaCoO3 is a promising SOFC cathode material. The domain structures and the oxidation state of Co in Ca-doped LaCoO3, which are directly related to its mechanical properties and electronic conductivity, are investigated by in-situ TEM and EELS. The formation of microcracks is observed during thermal cycles. Ca-doping in LaCoO3 is shown to not only improve the electronic conductivity of the material, but is also likely to strengthen the grain boundaries. The realization of its application in SOFCs depends on depressing the ferroelastisity to reduce strain formation during thermal cycles. The application of the (S)TEM techniques used for studying the perovskite systems are further extended to other compounds containing transition metal elements. The refractory minerals from Comet 81 P/Wild-2 are studied to investigate the formation of the early solar system. A relatively high Ti3+/Ti 4

  7. Seismic exploration methods for hydrothermal dolomite reservoirs: A case study of the Trenton-Black River groups

    NASA Astrophysics Data System (ADS)

    Ogiesoba, Osareni Christopher

    This thesis discusses 3D seismic exploration for hydrothermal dolomite (HTD) reservoirs. During this project, I utilized some of the existing algorithms as well as developed my own methods. I mentioned that HTD reservoirs constitute an important hydrocarbon play-type the world over, and are particularly important within the Ordovician aged Trenton-Black River Group in eastern North America. I noted that 3D seismic is the best tool to explore for HTD but it is adversely affected by random noise and acquisition footprint which must be attenuated. I designed a post-stack processing flow that can be applied to attenuate noise, highlight fault terminations, and increase reflection events continuity. By predicting porosity using seismic attributes, I examined the relationships between porosity distribution and faulting, and between porosity and seismic attributes. Results show that porosity development depends on basement-related faults, and that hydrocarbon production rate depends on the presence of faults, fractures and porosity. The results show that the sag observed to be associated with HTD reservoirs on seismic sections is due to velocity pull-down and that the best porosity is developed in these areas. The methods and results presented in this project can be used in other places with similar geologic settings. By way of semblance, I developed a dual-parameter scanning algorithm that can recover both NMO velocity (vnmo) and the effective anisotropic parameter (etaeff) at the same time, from which interval eta (etaint) is obtained by inversion. Noise-free synthetic data application show 10% maximum deviation between the extracted and actual flint values, while noise-contaminated synthetic data show >20% deviation. Real data application shows that it is possible to discriminate between HTD and limestone. Further testing is required to establish its validity. A velocity ratio (Vp/Vs) extracting algorithm was developed using AVO prestack amplitude inversion. Noise

  8. Shallow gas in Cenozoic sediments of the Southern North Sea

    NASA Astrophysics Data System (ADS)

    Trampe, Anna F.; Lutz, Rüdiger; Franke, Dieter; Thöle, Hauke; Arfai, Jashar

    2013-04-01

    Shallow petroleum systems in the southern North Sea are known for several decades but they were not actively explored for a long time. In recent years these unconventional shallow petroleum systems are studied in greater detail and one shallow gas field (A-12) is in production in the Netherlands. Additionally, oil was encountered in Miocene sandstones in the southern Danish North Sea (Lille John well) just north of the Danish-German border. Seismic amplitude anomalies are an indication for hydrocarbons in sediments. Therefore we have mapped the occurrence of seismic amplitude anomalies in the German North Sea based on more than 25.000 km of 2D seismic data and around 4.000 km2 of 3D seismic data. Amplitude anomalies are ubiquitous phenomena in the study area. These anomalies are not only caused by hydrocarbons but also by changing lithologies e.g. peat or fluid migration. Therefore several classes of seismic anomalies, e.g. bright spots, chimneys, blanking areas and velocity pull-down were mapped. Examples for these classes were studied with AVO (amplitude variation with offset) analyses to verify the existence or non-existence of gas in the sediments. Shallow gas can be produced and transported through the dense pipeline grid of the southern and central North Sea or it could be burned offshore close to wind parks in small power plants and the electric energy then transported through the existing power connections of the wind parks. Thus enabling a continuous energy supply during calm wind periods. This study is carried out within the framework of the project "Geoscientific Potential of the German North Sea (GPDN)" in which the Cenozoic sedimentary system was mapped in great detail. A detailed model of delta evolution (Baltic river system) was developed which serves as a structural framework. The studied interval is time equivalent to the Utsira formation which is used offshore Norway for sequestration of CO2. These different possibilities of using or exploiting

  9. The relations between natural gas hydrate distribution and structure on Muli basin Qinghai province

    NASA Astrophysics Data System (ADS)

    Yu, C.; Li, Y.; Lu, Z.; Luo, S.; Qu, C.; Tan, S.; Zhang, P.

    2014-12-01

    The Muli area is located in a depression area which between middle Qilian and south Qilian tectonic elements. The natural gas hydrate stratum belongs the Jurassic series coal formation stratum, the main lithological character clamps the purple mudstone, the siltstone, the fine grain sandstone and the black charcoal mudstone for the green gray. The plutonic metamorphism is primarily deterioration function of the Muli area coal, is advantageous in forming the coal-bed gas. Cretaceous system, the Paleogene System and Neogene System mainly include the fine grain red clastic rock and clay stone. The distribution of Quaternary is widespread. The ice water - proluvial and glacier deposit are primarily depositional mode. The Qilian Montanan Muli permafrost area has the good gas source condition (Youhai Zhu 2006) and rich water resources. It is advantage to forming the natural gas hydrate. The natural gas hydrate is one kind of new latent energy, widely distributes in the mainland marginal sea bottom settlings and land permanent tundra. Through researching the area the structure ,the deposition carries on the analysis and responds the characteristic analysis simulation in the rock physics analysis and the seismic in the foundation, and then the reflected seismic data carried by tectonic analysis processing and the AVO characteristic analysis processing reveal that the research area existence natural gas hydrate (already by drilling confirmation) and the natural gas hydrate distribution and the structure relations is extremely close. In the structure development area, the fault and the crevasse crack growing, the natural gas hydrate distribution characteristic is obvious (this is also confirmed the storing space of natural gas hydrate in this area is mainly crevasse crack). This conclusion also agree with the actual drilling result. The research prove that the distribution of natural gas hydrate in this area is mainly controlled by structure control. The possibility of fault

  10. Tying rock properties from core to depositional processes and examining the relationship through forward seismic reflection modeling in the Kaiparowits Plateau, Utah

    NASA Astrophysics Data System (ADS)

    Dworsky, Karenth

    Nearshore fluvial to tidal transitional depositional systems are becoming increasingly important due to the large number of global hydrocarbon reserves held in such deposits. These deposits are inherently complex due to their heterolithic nature and therefore, interpreting facies and facies relationships in seismic reflection profiles is problematic. The fluvial and tidally influenced nearshore deposits of the late Cretaceous John Henry Member (JHM) of the Straight Cliffs Formation, located in the Kaiparowits Plateau of southern Utah, offers an excellent opportunity to improve our understanding of how the fluvial to tidal transition impacts subsurface petroleum reservoirs and their expression in seismic reflection profiles. The focus of the first chapter is to investigate the impact of heterogeneous depositional environments and their rock properties to model amplitude versus offset (AVO) using a single core. Core EP-25 exhibits lithofacies from a progradational succession, from shoreface through tidal to fluvial. In order to model the most likely lithofacies stacking patterns present in the core, Markov Chain analysis was conducted. Benchtop measurements performed on 1 inch core plugs obtained rock properties (Vp, Vs, density, permeability, and porosity) for each lithofacies. Average rock properties for each lithofacies were used to generate synthetic seismic reflection models of the different upward fining facies associations documented directly from the core, in order to model variations in amplitude versus offset responses as a function of variable tidal influence. The focus of the second chapter is to capture probable 3-dimensional geobody distributions with a particular focus on coal geobody distribution using previously studied cores and outcrops on the plateau. Three different seismic forward models were created ranging in complexity, using cores EP-25, EP-07, density logs, and the nearby outcrop study Left Hand Collet. The rock properties obtained from the

  11. Global transcriptional analysis of nitrogen fixation and ammonium repression in root-associated Pseudomonas stutzeri A1501

    PubMed Central

    2010-01-01

    Background Biological nitrogen fixation is highly controlled at the transcriptional level by regulatory networks that respond to the availability of fixed nitrogen. In many diazotrophs, addition of excess ammonium in the growth medium results in immediate repression of nif gene transcription. Although the regulatory cascades that control the transcription of the nif genes in proteobacteria have been well investigated, there are limited data on the kinetics of ammonium-dependent repression of nitrogen fixation. Results Here we report a global transcriptional profiling analysis of nitrogen fixation and ammonium repression in Pseudomonas stutzeri A1501, a root-associated and nitrogen-fixing bacterium. A total of 166 genes, including those coding for the global nitrogen regulation (Ntr) and Nif-specific regulatory proteins, were upregulated under nitrogen fixation conditions but rapidly downregulated as early as 10 min after ammonium shock. Among these nitrogen fixation-inducible genes, 95 have orthologs in each of Azoarcus sp. BH72 and Azotobacter vinelandii AvoP. In particular, a 49-kb expression island containing nif and other associated genes was markedly downregulated by ammonium shock. Further functional characterization of pnfA, a new NifA-σ54-dependent gene chromosomally linked to nifHDK, is reported. This gene encodes a protein product with an amino acid sequence similar to that of five hypothetical proteins found only in diazotrophic strains. No noticeable differences in the transcription of nifHDK were detected between the wild type strain and pnfA mutant. However, the mutant strain exhibited a significant decrease in nitrogenase activity under microaerobic conditions and lost its ability to use nitrate as a terminal electron acceptor for the support of nitrogen fixation under anaerobic conditions. Conclusions Based on our results, we conclude that transcriptional regulation of nif gene expression in A1501 is mediated by the nif-specific and ntr gene

  12. Effectiveness of imaging seismic attenuation using visco-acoustic full waveform tomography: Examples from the Seattle Fault Zone and Northern Perth Basin

    NASA Astrophysics Data System (ADS)

    Takam Takougang, E.; Calvert, A. J.

    2012-12-01

    Attenuation characterizes the decrease in amplitude of seismic waves as they propagate away from the source. A seismic wave propagating in the subsurface will suffer from two types of attenuation: Intrinsic attenuation and scattering attenuation. Scattering attenuation is due to small scale heterogeneity in the subsurface, whereas intrinsic attenuation arises from inelastic rock properties. Intrinsic attenuation can provide key information about the subsurface, which can be of value to the mining as well as the oil and gas industry. However, accurate imaging of intrinsic seismic attenuation using visco-acoustic full-waveform tomography is not straight forward. Attenuation models recovered by visco-acoustic waveform tomography are often contain contaminated by scattering effects as well as elastic mode conversion artefacts due to the inability of the visco-acoustic approximation to perfectly predict the amplitude of visco-elastic field data. The effect of scattering can be reduced if a velocity model with a high resolution is used. This usually necessitates a two-step inversion approach consisting of first recovering the velocity model and later, the attenuation model. In this study, we present a specific preconditioning of the data based on matching the amplitude variation with offset (AVO) of the field and modelled visco-acoustic data, and a specific inversion approach based on a sequential recovering of the seismic velocity and attenuation models using the visco-acoustic approximation. Our purpose is to improve the quality of the recovered attenuation model by decoupling the reconstruction of velocity and attenuation, thus reducing artefacts. We apply the method to two different areas: The Seattle Fault Zone in Puget Sound in the northwestern USA, using marine seismic reflection data from the Seismic Hazards investigation in Puget Sound (SHIPS) survey collected in 1998, and the Allanooka area within the Northern Perth Basin using high resolution seismic

  13. 3D multicomponent seismic characterization of a clastic reservoir in the Middle Magdalena Valley Basin, Colombia

    NASA Astrophysics Data System (ADS)

    Velasquez-Espejo, Antonio Jose

    formations. The attribute extraction from the inverted P-wave amplitude for both acoustic impedance and VP/VS ratio allowed the characterization of stratigraphic features, in particular some channel geometries that are interpreted as part of a meandering fluvial system (point bars and crevasse splays). The lithological and petrophysical correlation of additional attributes from the elastic inversion and AVO is not reliable since there is no independent density, porosity, resistivity, permeability, etc., measurements to guarantee accurate and stable results; nonetheless VP/VS analysis using multicomponent seismic in the MMVB shows significant promise. Therefore, the acquisition of critical log data with new well drilling as well as an additional multi-attribute analysis based on AVO and a joint PP-PS inversion are strongly recommended.

  14. Time lapse seismic observations and effects of reservoir compressibility at Teal South oil field

    NASA Astrophysics Data System (ADS)

    Islam, Nayyer

    One of the original ocean-bottom time-lapse seismic studies was performed at the Teal South oil field in the Gulf of Mexico during the late 1990's. This work reexamines some aspects of previous work using modern analysis techniques to provide improved quantitative interpretations. Using three-dimensional volume visualization of legacy data and the two phases of post-production time-lapse data, I provide additional insight into the fluid migration pathways and the pressure communication between different reservoirs, separated by faults. This work supports a conclusion from previous studies that production from one reservoir caused regional pressure decline that in turn resulted in liberation of gas from multiple surrounding unproduced reservoirs. I also provide an explanation for unusual time-lapse changes in amplitude-versus-offset (AVO) data related to the compaction of the producing reservoir which, in turn, changed an isotropic medium to an anisotropic medium. In the first part of this work, I examine regional changes in seismic response due to the production of oil and gas from one reservoir. The previous studies primarily used two post-production ocean-bottom surveys (Phase I and Phase II), and not the legacy streamer data, due to the unavailability of legacy prestack data and very different acquisition parameters. In order to incorporate the legacy data in the present study, all three post-stack data sets were cross-equalized and examined using instantaneous amplitude and energy volumes. This approach appears quite effective and helps to suppress changes unrelated to production while emphasizing those large-amplitude changes that are related to production in this noisy (by current standards) suite of data. I examine the multiple data sets first by using the instantaneous amplitude and energy attributes, and then also examine specific apparent time-lapse changes through direct comparisons of seismic traces. In so doing, I identify time-delays that, when

  15. Deep suture zone in the North Barents Basin

    NASA Astrophysics Data System (ADS)

    Butsenko, Viktor; Kireev, Artem; Piskarev, Alexey; Savin, Vasily; Smirnov, Oleg

    2015-04-01

    magnetization. Calculated basement magnetization is 1.9 A/m to the West from an anomaly zone that is a characteristic for many igneous and metamorphic rocks of the diorite composition. Magnetization of the basement formations sharply increases to 3.6 A/m to the East. Similar values of magnetization are characterized basalts and dolerites, and also many metamorphic rocks of the basic and ultrabasic composition. Thus, the simulated magnetic field anomaly not only corresponds to limits of the heterochronous sedimentary basins, but also shows the border between two heterogeneous basement blocks. "Bright spot" anomalies are marked out on seismic sections. Bright spots are mainly located near the zone of negative magnetic anomaly along the East part of the North Barents Basin. The AVO analysis of the anomalies of the seismic recording has allowed to allocate possible hydrocarbon reservoirs and to subdivide them into the gas-saturated and oil-gas-saturated.

  16. Explosions of andesitic volcanoes in Kamchatka and danger of volcanic ash clouds to aviation

    NASA Astrophysics Data System (ADS)

    Gordeev, E. I.; Girina, O. A.; Neal, C. A.

    2010-12-01

    created the International KVERT Project, uniting scientists IVS FEB RAS, KB GS RAS and AVO USGS. To solve this problem and provide early warning of air services on the volcanic hazard, scientists analyze the data of seismic, video, visual and satellite monitoring of volcanoes of Kamchatka. In case of ash explosion, cloud or plume detection, information is sending via e-mail operatively to all interested users. Scientists collect all the information (research data, descriptions of eruptions from the literature, observations of tourists, etc.) of the active volcanoes. Based on analysis of historical activity Bezymianny, as well as its continuous monitoring data, scientists of KVERT Project repeatedly predicted the eruption of this volcano. It allowed notifying in time air services of the impending danger of aircraft. For example, in 2001-2010, were predicted 9 of its eruptions (December 16, 2001; December 25, 2002; January 11, 2005; May 9, 2006; May 11, 2007; October 14-15, 2007; August 19, 2008; December 16, 2009; May 31, 2010).

  17. Optical satellite data volcano monitoring: a multi-sensor rapid response system

    USGS Publications Warehouse

    Duda, Kenneth A.; Ramsey, Michael; Wessels, Rick L.; Dehn, Jonathan

    2009-01-01

    In this chapter, the use of satellite remote sensing to monitor active geological processes is described. Specifically, threats posed by volcanic eruptions are briefly outlined, and essential monitoring requirements are discussed. As an application example, a collaborative, multi-agency operational volcano monitoring system in the north Pacific is highlighted with a focus on the 2007 eruption of Kliuchevskoi volcano, Russia. The data from this system have been used since 2004 to detect the onset of volcanic activity, support the emergency response to large eruptions, and assess the volcanic products produced following the eruption. The overall utility of such integrative assessments is also summarized. The work described in this chapter was originally funded through two National Aeronautics and Space Administration (NASA) Earth System Science research grants that focused on the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument. A skilled team of volcanologists, geologists, satellite tasking experts, satellite ground system experts, system engineers and software developers collaborated to accomplish the objectives. The first project, Automation of the ASTER Emergency Data Acquisition Protocol for Scientific Analysis, Disaster Monitoring, and Preparedness, established the original collaborative research and monitoring program between the University of Pittsburgh (UP), the Alaska Volcano Observatory (AVO), the NASA Land Processes Distributed Active Archive Center (LP DAAC) at the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center, and affiliates on the ASTER Science Team at the Jet Propulsion Laboratory (JPL) as well as associates at the Earth Remote Sensing Data Analysis Center (ERSDAC) in Japan. This grant, completed in 2008, also allowed for detailed volcanic analyses and data validation during three separate summer field campaigns to Kamchatka Russia. The second project, Expansion and synergistic use

  18. Seismic and Geodetic Investigation of the 1996-1998 Earthquake Swarm at Strandline Lake, Alaska

    NASA Astrophysics Data System (ADS)

    Kilgore, W.; Roman, D. C.; Power, J. A.; Hansen, R. A.; Biggs, J.

    2009-12-01

    Microearthquake (< M3.0) swarms occur frequently in volcanic environments, but do not always culminate in an eruption. Such non-eruptive swarms may be caused by stresses induced by magma intrusion, hydrothermal fluid circulation, or regional tectonic processes, such as slow-slip earthquakes. Strandline Lake, located 30 km northeast of Mount Spurr volcano in south-central Alaska, experienced a strong earthquake swarm between August 1996 and August 1998. The Alaska Volcano Observatory (AVO) catalog indicates that a total of 2,999 earthquakes were detected during the swarm period, with a maximum magnitude of Mw 3.1 and a depth range of 0-30 km below sea level (with the majority of catalog hypocenters located between 5-10 km BSL). The cumulative seismic moment of the swarm was 2.03e15 N m, equivalent to a cumulative magnitude of Mw 4.2. Because of the swarm's distance from the nearest Holocene volcanic vent, seismic monitoring was poor and gas and deformation data for the swarm period do not exist. However, combined waveforms from a dense seismic network on Mount Spurr and from several regional seismic stations allowed us to re-analyze the swarm earthquakes. We first developed a new 1-D velocity model for the Strandline Lake region by re-picking and inverting precise arrival times for 27 large Strandline Lake earthquakes. The new velocity model reduced the average RMS for these earthquakes from 0.16 to 0.11s, and the average horizontal and vertical location errors from 3.3 to 2.5 km and 4.7 to 3.0 km, respectively. Depths of the 27 earthquakes ranged from 10.5 to 22.1 km with an average depth of 16.6 km. A moderately high b-value of 1.33 was determined for the swarm period, possibly indicative of magmatic activity. However, a similarly high b-value of 1.25 was calculated for the background period. 28 well-constrained fault plane solutions for both swarm and background earthquakes indicate a diverse mixture of strike-slip, dip-slip, and reverse faulting beneath

  19. Emission rates of sulfur dioxide and carbon dioxide from Redoubt Volcano, Alaska during the 1989-1990 eruptions

    USGS Publications Warehouse

    Casadevall, T.J.; Doukas, M.P.; Neal, C.A.; McGimsey, R.G.; Gardner, C.A.

    1994-01-01

    pressurization of the shallow magma system and an increase in earthquake activity. Unlike the short-term SO2 decrease in March 1990, the long-term decrease of sulfur dioxide emission rates from March 1990 through May 1991 was coincident with low rates of seismic energy release and was interpreted to reflect gradual depressurization of the shallow magma reservoir. The long-term declines in seismic energy release and in SO2 emission rates led AVO scientists to conclude on April 19, 1991 that the potential for further eruptive activity from Redoubt Volcano had diminished, and on this basis, the level of concern color code for the volcano was changed from code yellow (Volcano is restless; earthquake activity is elevated; activity may include extrusion of lava) to code green (Volcano is in its normal 'dormant' state). ?? 1994.

  20. Multi-physics and multi-scale characterization of shale anisotropy

    NASA Astrophysics Data System (ADS)

    Sarout, J.; Nadri, D.; Delle Piane, C.; Esteban, L.; Dewhurst, D.; Clennell, M. B.

    2012-12-01

    m scale). For each of the above properties, leading-edge experimental techniques have been associated with novel interpretation tools. In this contribution, these experimental and interpretation methods are described. Relationships between the measured properties and the corresponding micro-/meso-structural features are discussed. For example, P-wave velocity was measured along 100 different propagation paths on a single cylindrical shale specimen using miniature ultrasonic transducers. Assuming that (i) the elastic tensor of this shale is transversely isotropic; and (i) the sample has been cored perfectly perpendicular to the bedding plane (symmetry plane is horizontal), Thomsen's anisotropy parameters inverted from the measured velocities are: - P-wave velocity along the symmetry axis (perpendicular to the bedding plane) αo=3.45km/s; - P-wave anisotropy ɛ=0.12; - Parameter controlling the wave front geometry δ=0.058. A novel inversion algorithm allows for recovering these parameters without assuming a priori a horizontal bedding (symmetry) plane. The inversion of the same data set using this algorithm yields (i) αo=3.23km/s, ɛ=0.25 and δ=0.18, and (ii) the elastic symmetry axis is inclined of ω=30° with respect to the specimen's axis. Such difference can have strong impact on field applications (AVO, ray tracing, tomography).

  1. Improved Near-surface Velocity Models from Waveform Tomography Applied to Vibroseis MCS Reflection Data

    NASA Astrophysics Data System (ADS)

    Smithyman, B.; Clowes, R. M.

    2009-12-01

    sufficiently accurate starting model must be provided to allow convergence to an accurate final model. The Q-filter and deconvolution effects are theoretically accounted for in the waveform inversion process, once a starting model of sufficient quality is realized. To make this possible, preprocessing for waveform inversion is also necessary. It is designed to allow the use of the 2D, acoustic approximation to the wave equation in the waveform inversion implementation. The use of a 2D approximation to the true 3D geometry introduces AVO (Amplitude Variation with Offset) errors that must be accounted for in order for attenuation inversion to be possible. The acoustic approximation means that elastic propagation modes and mode-converted arrivals must be considered as systematic noise, with appropriate preprocessing steps to reduce their effects. Careful analysis of the early-arriving waveforms is necessary to deal with approximations due to the waveform inversion implementation, which are not easily separable from the approximations implicit in vibroseis acquisition. However, the potential benefits in near-surface velocity characterization and their wide applicability make the results of this research important for seismic processing and near-surface geological interpretation.

  2. Multicomponent Seismic Analysis and Calibration to Improve Recovery from Algal Mounds: Application to the Roadrunner/Towaoc area of the Paradox Basin, UTE Mountain UTE Reservation, Colorado

    SciTech Connect

    Joe Hachey

    2007-09-30

    of this upgrade to nine components was to provide additional shear wave component data that might prove useful in delineating internal mound reservoir attributes. Also, Red Willow extended the P-wave portion of the survey to the northwest of the original 6 mi{sup 2} (15.6 km{sup 2}) 3D9C area in order to extend coverage further to the northwest to the Marble Wash area. In order to accomplish this scope of work, 3D9C seismic data set covering two known reservoirs was acquired and processed. Three-dimensional, zero-offset vertical seismic profile (VSP) data was acquired to determine the shear wave velocities for processing the sh3Dseismic data. Anisotropic velocity, and azimuthal AVO processing was carried out in addition to the conventional 3D P-wave data processing. All P-, PS- and S-wave volumes of the seismic data were interpreted to map the seismic response. The interpretation consisted of conventional cross-plots of seismic attributes vs. geological and reservoir engineering data, as well as multivariate and neural net analyses to assess whether additional resolution on exploration and engineering parameters could be achieved through the combined use of several seismic variables. Engineering data in the two reservoirs was used to develop a combined lithology, structure and permeability map. On the basis of the seismic data, a well was drilled into the northern mound trend in the project area. This well, Roadrunner No.9-2, was brought into production in late April 2006 and continues to produce modest amounts of oil and gas. As of the end of August 2007, the well has produced approximately 12,000 barrels of oil and 32,000 mcf of gas. A static reservoir model was created from the seismic data interpretations and well data. The seismic data was tied to various markers identified in the well logs, which in turn were related to lithostratigraphy. The tops and thicknesses of the various units were extrapolated from well control based upon the seismic data that was

  3. A Portrait of One Hundred Thousand and One Galaxies

    NASA Astrophysics Data System (ADS)

    2002-08-01

    Rich and Inspiring Experience with NGC 300 Images from the ESO Science Data Archive Summary A series of wide-field images centred on the nearby spiral galaxy NGC 300 , obtained with the Wide-Field Imager (WFI) on the MPG/ESO 2.2-m telescope at the La Silla Observatory , have been combined into a magnificent colour photo. These images have been used by different groups of astronomers for various kinds of scientific investigations, ranging from individual stars and nebulae in NGC 300, to distant galaxies and other objects in the background. This material provides an interesting demonstration of the multiple use of astronomical data, now facilitated by the establishment of extensively documented data archives, like the ESO Science Data Archive that now is growing rapidly and already contains over 15 Terabyte. Based on the concept of Astronomical Virtual Observatories (AVOs) , the use of archival data sets is on the rise and provides a large number of scientists with excellent opportunities for front-line investigations without having to wait for precious observing time. In addition to presenting a magnificent astronomical photo, the present account also illustrates this important new tool of the modern science of astronomy and astrophysics. PR Photo 18a/02 : WFI colour image of spiral galaxy NGC 300 (full field) . PR Photo 18b/02 : Cepheid stars in NGC 300 PR Photo 18c/02 : H-alpha image of NGC 300 PR Photo 18d/02 : Distant cluster of galaxies CL0053-37 in the NGC 300 field PR Photo 18e/02 : Dark matter distribution in CL0053-37 PR Photo 18f/02 : Distant, reddened cluster of galaxies in the NGC 300 field PR Photo 18g/02 : Distant galaxies, seen through the outskirts of NGC 300 PR Photo 18h/02 : "The View Beyond" ESO PR Photo 18a/02 ESO PR Photo 18a/02 [Preview - JPEG: 400 x 412 pix - 112k] [Normal - JPEG: 1200 x 1237 pix - 1.7M] [Hi-Res - JPEG: 4000 x 4123 pix - 20.3M] Caption : PR Photo 18a/02 is a reproduction of a colour-composite image of the nearby spiral galaxy