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Sample records for kutsar avo trumm

  1. Anisotropy and AVO from walkaways

    SciTech Connect

    Leaney, W.S.

    1994-12-31

    A multi-offset VSP or ``walkaway`` is a wide aperture borehole seismic experiment ideal for studying angle-dependent wave propagation. In this paper, two aspects of elastic wave propagation are studied with walkaways: anisotropy (transverse isotropy) and AVO (amplitude variation with offset). Anisotropy is measured from walkaway data using extracted vertical and horizontal phase slownesses. Results are shown for a Java Sea walkaway data set and tabulated for walkaways from different locations. The anisotropy measurements are classified using Schoenberg`s parameters of ellipticity and anellipticity. Shale anisotropy is found to be significant and variable. Anisotropic AVO is studied on Ostrander`s shale-sand model and through the computation of anisotropic ray-trace synthetics. The ratio of ellipticity to anellipticity is found to be a good measure of shale anisotropy in the context of AVO. Depending on the ``flavor`` of shale anisotropy, AVO can be significantly reduced or exaggerated. The AVO response of a reservoir sequence can also be measured (as opposed to modeled) with a properly designed walkaway. The results of processing a walkaway for AVO are shown. Such a seismic experiment is arguably the best way to determine the AVO response of a reservoir or reservoir sequence. Together, these two new applications of walkaways -- to measure anisotropy and AVO -- can be used to: (1) Establish the viability of using AVO to map a reservoir. (2) Reduce the risk involved with the added cost of AVO studies. (3) Improve the reliability of AVO interpretations.

  2. Conventional AVO in unconventional places

    SciTech Connect

    Wepfer, B.

    1994-12-31

    Can AVO analysis (amplitude variations with offset in seismic data, a.k.a. amplitude versus offset) only be applied in the ``classic`` situation of a gas sand encased in shale? Are deeper onshore targets off-limits for amplitude work? Does AVO only ``work`` with gas sands? What about carbonate terrains, oil sands, and deep onshore targets? Will AVO prove helpful in these instances? Maybe the same basic ideas can be applied in some historically non-AVO areas, through this may necessitate employing slightly different methods. AVO has traditionally been used to generate gas leads in the offshore Gulf of Mexico, following in the footsteps of the seminal work by Ostrander (1984). However, this certainly isn`t the only locale where amplitudes can serve as a pay locator. AVO can accurately delineate known pay in oil sands, fractured carbonates, deep onshore sands, and where the data quality is extremely poor, as proven by examples form around the globe. Therefore, companies should seriously consider employing standard AVO ideas in areas where it generally has not been used.

  3. 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.

  4. 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.

  5. Three-parameter AVO crossplotting in anisotropic media

    USGS Publications Warehouse

    Chen, H.; Castagna, J.P.; Brown, R.L.; Ramos, A.C.B.

    2001-01-01

    Amplitude versus offset (AVO) interpretation can be facilitated by crossplotting AVO intercept (A), gradient (B), and curvature (C) terms. However, anisotropy, which exists in the real world, usually complicates AVO analysis. Recognizing anisotropic behavior on AVO crossplots can help avoid AVO interpretation errors. Using a modification to a three-term (A, B, and C) approximation to the exact anisotropic reflection coefficients for transversely isotropic media, we find that anisotropy has a nonlinear effect on an A versus C crossplot yet causes slope changes and differing intercepts on A versus B or C crossplots. Empirical corrections that result in more accurate crossplot interpretation are introduced for specific circumstances.

  6. 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.

  7. AVO Seismic data inversion using global simultaneous technique

    NASA Astrophysics Data System (ADS)

    Eladj, S.; Ouadfeul, S.; Aliouane, L.; Djarfour, N.

    2012-04-01

    The main objective of this work is to apply the global simultaneous inversion of AVO real seismic data of the NORNE petroleum field located in the North Sea. Inversion has been applied to characterize the physical reservoir properties in term of acoustic impedance, Poisson's coefficient and Density. The proposed technique is applied at a small seismic cube of an hydrocarbon reservoir. Obtained results consists of the three cube cited above. Comparison of these last with a well-logs data of a borehole located in the area shows that the global simultaneous inversion can be used for reservoir properties prediction. These results can be used by geoscientists for better reservoir characterization and built a sub-surface dynamic model. The goal is to minimize the hydrocarbon exploration uncertainly. Keywords: global simultaneous inversion, AVO, North Sea, cube, reservoir characterization.

  8. 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.

  9. 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.

  10. Spectral decomposition aids AVO analysis in reservoir characterization: A case study of Blackfoot field, Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Jung Yoon, Wang; Farfour, Mohammed

    2012-09-01

    Blackfoot field, Alberta, Canada, has produced oil and gas from a Glauconitic compound incised valley-system. In this area channels can be filled with sands and/or shales. Differentiation of prospective channel sands and non-productive shales was always problematic due to the similarity in P-wave impedance of these two lithotypes. We study the spectral decomposition response to the hydrocarbons presence in the Glauconitic channel of Early Cretaceous age. From previous AVO analysis and modeling, a strong Class III AVO anomaly has been observed at the top of the porous sandstone in the upper valley, whereas shale had a very different AVO response. Furthermore, AVO inversion revealed additional information about lithology and fluid content in the channel. Our workflow starts from selecting a continuous horizon that was close and conforms to the channel interval; we then run spectral analyses for the channel area. Short Window Fourier Transform workflow could successfully image the channel's stratigraphic features and confirm results obtained from AVO analysis and inversion run on the data before being stacked. Additionally, the producing oil wells in the sand-fill channel were found to be correlating with high spectrum amplitude; while the dry wells in the shale-plugged channel fell in low amplitude anomaly.

  11. A study on the seismic AVO signatures of deep fractured geothermal reservoirs in an intrusive basement.

    NASA Astrophysics Data System (ADS)

    Aleardi, M.; Mazzotti, A.

    2012-04-01

    Amplitude-variation-with-offset (AVO) analysis of reflected waves has become an important tool for hydrocarbon prospecting. However, while the AVO responses of reservoirs in clastic lithologies (oil or gas bearing sands) are well known, the AVO behaviour of reservoirs hosted in the interconnected fractures of massive rocks are almost unknown due to the rarity of this type of reservoirs and the consequent lack of seismic and well log data. Thanks to the availability of the data of boreholes that ENEL GreenPower drilled in the deep intrusive basement of the Larderello-Travale geothermal field, we have derived the expected AVO responses of the vapour reservoirs found in some intensely, but very localized, fractured volumes within the massive rocks. Therefore we wish to determine what are the expected AVO responses of geothermal reservoirs inside fractured igneous rocks and we seek to find one or more AVO attributes that may help identifying fracture locations. To this end, we have analysed the velocity (P-wave and S-wave) and the density logs pertaining to three wells which reached five deep fractured zones in the basement. However, comparing well log data with surface seismic data the known issues of the different scales and thus different resolutions arise. Therefore, making use of the Backus theory of the equivalent layer, we have downscaled the well logs, acquired at a decimetric scale, to a decametric scale typical of the wavelengths of seismic waves, producing a blocky model of the original logs. Subsequently, we have followed two different approaches to estimate the expected responses. First, on the basis of the P and S velocities and densities of the fractured level and of the encasing rock, we have computed the analytical AVO response of each fractured zone. To this end we have made use of the linear Shuey equation that well describes the AVO response up to incident angles of 30 degrees. This would be the theoretical, noise free, response that perfectly

  12. 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.

  13. Applying Statistical Rock Physics to Quantify the Effects of Geologic Heterogeneities on Seismic AVO Signatures in Offshore Venezuela

    NASA Astrophysics Data System (ADS)

    Mukerji, T.; Gonzalez, E.; Cobos, C.; Hung, E.; Mavko, G.

    2002-12-01

    The objective of this study was to better understand observed amplitude anomalies, and quantify the geologic uncertainty associated with the feasibility of using seismic AVO signatures to detect hydrocarbons in offshore Venezuela region. Data from four wells were analyzed. Prediction of shear velocity was carried out in selected wells as none of the wells have shear logs. Sand and shale properties were estimated from selected zones based on the gamma-ray logs and geologic information about the formations. Fluid substitution was carried out within the sand zones taking into account the properties of the reservoir fluids. Monte-Carlo (MC) simulations, incorporating statistical variability and correlations of rock properties, were used to compute normal-incidence reflectivity and AVO gradient for different pore fluid conditions: brine sands, oil sands and gas sands. The computed seismic signatures were used to evaluate the feasibility of using seismic AVO for pore fluid and lithology discrimination. Forward modeling of CDP gathers was carried out and AVO signatures from synthetic CDP gathers were compared to MC simulations. The main conclusions are: statistical rock physics and AVO modeling analyses of data from wells indicate that Pliocene gas/oil sands are expected to have observable seismic amplitude and AVO signatures, with negative R(0) and small gradient G at top sand. However, the signature changes from Pliocene to Miocene sands. Depth-dependent geologic trends in AVO patterns were identified using data from Pliocene and Miocene sands. Directly using Pliocene AVO patterns to interpret amplitudes from Miocene sands without correcting for the trend could lead to potential pitfalls. Miocene sands are expected to have much weaker fluid signatures, as they are high velocity, stiff sands. Volcanoclastics and carbonates are other possible sources of strong amplitude and AVO signatures, and hence may cause false alarms if not properly interpreted. A combination of

  14. 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

  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. Application of AVO analysis to gas hydrates identification in the northern slope of the South China Sea

    NASA Astrophysics Data System (ADS)

    Yang, Rui; Yan, Pin; Wu, Nengyou; Sha, Zhibin; Liang, Jinqiang

    2014-08-01

    Amplitude versus offset (AVO) analysis is a conventional seismic exploration technique in geophysical and lithological interpretation and has been widely used in onshore and offshore exploration. Its use in marine gas hydrate research, however, is still in initial stages. In this study, AVO analysis is applied to seismic profiles at drilling sites where hydrate samples have been recovered. The AVO responses of free gas, bottom simulating reflector (BSRs), and gas hydrates are discussed, and the AVO attributes in relation to gas hydrates are summarized. The results show that changes in intercept, gradient, fluid factor and Poisson's ratio clearly reflect: (i) location of free gas and the BSR, and (ii) spatial relations between blank zone, BSR, gas hydrate, and free gas.

  17. Brittleness index calculation and evaluation for CBM reservoirs based on AVO simultaneous inversion

    NASA Astrophysics Data System (ADS)

    Wu, Haibo; Dong, Shouhua; Huang, Yaping; Wang, Haolong; Chen, Guiwu

    2016-11-01

    In this paper, a new approach is proposed for coalbed methane (CBM) reservoir brittleness index (BI) calculations. The BI, as a guide for fracture area selection, is calculated by dynamic elastic parameters (dynamic Young's modulus Ed and dynamic Poisson's ratio υd) obtained from an amplitude versus offset (AVO) simultaneous inversion. Among the three different classes of CBM reservoirs distinguished on the basis of brittleness in the theoretical part of this study, class I reservoirs with high BI values are identified as preferential target areas for fracturing. Therefore, we derive the AVO approximation equation expressed by Ed and υd first. This allows the direct inversion of the dynamic elastic parameters through the pre-stack AVO simultaneous inversion, which is based on Bayes' theorem. Thereafter, a test model with Gaussian white noise and a through-well seismic profile inversion is used to demonstrate the high reliability of the inversion parameters. Accordingly, the BI of a CBM reservoir section from the Qinshui Basin is calculated using the proposed method and a class I reservoir section detected through brittleness evaluation. From the outcome of this study, we believe the adoption of this new approach could act as a guide and reference for BI calculations and evaluations of CBM reservoirs.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Reconnaissance amplitude versus offset techniques in the Niger Delta

    SciTech Connect

    Barton, J.; Gullette, K.

    1996-08-01

    Reconnaissance AVO (amplitude vs. offset) techniques have been invaluable in allowing the analyses and mapping of AVO on large-volume data sets in the Nigerian Niger Delta. Forward modelling of rock properties derived from well data on the shelf and regional ties of common depth point gathers to well control show that a shale on hydrocarbon bearing sand typically generates increasing amplitude with offset [Class 2 and Class 3 type anomalies of the Rutherford and Williams (1989) classification]. Consequently, processing and display techniques have been developed that distinguish the increasing amplitude with offset response associated with hydrocarbon bearing sands from the flatter AVO response of background water wet sands and shales. Attributes are created from angle stacks rather than by analyses of individual common depth point gathers over an entire data set. We show examples of a new AVO attribute which we call the Enhanced Restricted Gradient that highlights Class 2 and Class 3 type AVO anomalies more clearly than some of the standard AVO attributes used in the industry. The techniques described here provide a cost-effective and practical way of evaluating AVO character on large volume 2D and 3D data sets and should also be useful in other areas worldwide where hydrocarbon bearing reservoirs generate increasing amplitude with offset.

  7. 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

    2015-08-14

    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.

  8. 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.

  9. 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.; Power, John A.; Coombs, Michelle L.; Freymueller, Jeffrey T.

    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.

  10. [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

  11. Volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory 1993

    USGS Publications Warehouse

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

    1996-01-01

    During 1993, the Alaska Volcano Observatory (AVO) responded to episodes of eruptive activity or false alarms at nine volcanic centers in the state of Alaska. Additionally, as part of a formal role in KVERT (the Kamchatkan Volcano Eruption Response Team), AVO staff also responded to eruptions on the Kamchatka Peninsula, details of which are summarized in Miller and Kurianov (1993). In 1993, AVO maintained seismic instrumentation networks on four volcanoes of the Cook Inlet region--Spurr, Redoubt, Iliamna, and Augustine--and two stations at Dutton Volcano near King Cove on the Alaska Peninsula. Other routine elements of AVO's volcano monitoring program in Alaska include periodic airborne measurement of volcanic SO2 and CO2 at Cook Inlet volcanoes (Doukas, 1995) and maintenance of a lightning detection system in Cook Inlet (Paskievitch and others, 1995).

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Ripening-related gene from avocado fruit : ethylene-inducible expression of the mRNA and polypeptide.

    PubMed

    McGarvey, D J; Sirevåg, R; Christoffersen, R E

    1992-02-01

    Fruit ripening involves a series of changes in gene expression regulated by the phytohormone ethylene. AVOe3, a ripening-related gene in avocado fruit (Persea americana Mill. cv Hass), was characterized with regard to its ethylene-regulated expression. The AVOe3 mRNA and immunopositive protein were induced in mature fruit within 12 hours of propylene treatment. The AVOe3 mRNA levels reached a maximum 1 to 2 days before the ethylene climacteric, whereas the immunopositive protein continued to accumulate. RNA selected by the pAVOe3 cDNA clone encoded a polypeptide with molecular mass of 34 kilodaltons, corresponding to the molecular mass of the AVOe3 protein determined by immunoblots. The protein was soluble, remaining in solution at 100,000 gravity and eluted as a monomer on gel filtration. Because of its pattern of induction and relationship to an ethylene-related gene of tomato, the possible involvement of AVOe3 in ethylene biosynthesis is discussed.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. The Alaska Volcano Observatory - Expanded Monitoring of Volcanoes Yields Results

    USGS Publications Warehouse

    Brantley, Steven R.; McGimsey, Robert G.; Neal, Christina A.

    2004-01-01

    Recent explosive eruptions at some of Alaska's 52 historically active volcanoes have significantly affected air traffic over the North Pacific, as well as Alaska's oil, power, and fishing industries and local communities. Since its founding in the late 1980s, the Alaska Volcano Observatory (AVO) has installed new monitoring networks and used satellite data to track activity at Alaska's volcanoes, providing timely warnings and monitoring of frequent eruptions to the aviation industry and the general public. To minimize impacts from future eruptions, scientists at AVO continue to assess volcano hazards and to expand monitoring networks.

  5. 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.

  6. 78 FR 16864 - Agency Information Collection Activities: Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-19

    ... of volcanic activity in the U.S. in order to reduce the loss of life, property, and economic and... improve ash fall warning messages, AVO Volcanic Activity Notifications, and make fieldwork more efficient... Geological Survey Agency Information Collection Activities: Comment Request AGENCY: U.S. Geological...

  7. 77 FR 34400 - Agency Information Collection Activities: Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-11

    ... INFORMATION: I. Abstract The USGS provides warnings and notification to the public of volcanic activity in the... ash-fall reports have been filed will improve ash fall warning messages, AVO Volcanic Activity....S. Geological Survey Agency Information Collection Activities: Comment Request AGENCY:...

  8. 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.

  9. 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...

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Resolution enhancement of robust Bayesian pre-stack inversion in the frequency domain

    NASA Astrophysics Data System (ADS)

    Yin, Xingyao; Li, Kun; Zong, Zhaoyun

    2016-10-01

    AVO/AVA (amplitude variation with an offset or angle) inversion is one of the most practical and useful approaches to estimating model parameters. So far, publications on AVO inversion in the Fourier domain have been quite limited in view of its poor stability and sensitivity to noise compared with time-domain inversion. For the resolution and stability of AVO inversion in the Fourier domain, a novel robust Bayesian pre-stack AVO inversion based on the mixed domain formulation of stationary convolution is proposed which could solve the instability and achieve superior resolution. The Fourier operator will be integrated into the objective equation and it avoids the Fourier inverse transform in our inversion process. Furthermore, the background constraints of model parameters are taken into consideration to improve the stability and reliability of inversion which could compensate for the low-frequency components of seismic signals. Besides, the different frequency components of seismic signals can realize decoupling automatically. This will help us to solve the inverse problem by means of multi-component successive iterations and the convergence precision of the inverse problem could be improved. So, superior resolution compared with the conventional time-domain pre-stack inversion could be achieved easily. Synthetic tests illustrate that the proposed method could achieve high-resolution results with a high degree of agreement with the theoretical model and verify the quality of anti-noise. Finally, applications on a field data case demonstrate that the proposed method could obtain stable inversion results of elastic parameters from pre-stack seismic data in conformity with the real logging data.

  20. 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.

  1. 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.

  2. Mt. Spurr's 1992 eruptions

    USGS Publications Warehouse

    1993-01-01

    On 27 June, 1992, the Crater Peak vent on the south side of Mt. Spurr awoke from 39 years of dormancy and burst into sub-plinian eruption after 10 months of elevated seismicity. Two more eruptions followed in August and September. The volcano lies 125 km west of Anchorage, Alaska's largest city and an important international hub for air travel. The Alaska Volcano Observatory (AVO) was able to warn communities and the aviation industry well in advance of these eruptions.

  3. Impact of gate-source/drain channel architecture on the performance of an operational transconductance amplifier (OTA)

    NASA Astrophysics Data System (ADS)

    Kranti, Abhinav; Rashmi; Armstrong, G. Alastair

    2009-11-01

    In this work, we report on the significance of gate-source/drain extension region (also known as underlap design) optimization in double gate (DG) FETs to improve the performance of an operational transconductance amplifier (OTA). It is demonstrated that high values of intrinsic voltage gain (AVO_OTA) > 55 dB and unity gain frequency (fT_OTA) ~ 57 GHz in a folded cascode OTA can be achieved with gate-underlap channel design in 60 nm DG MOSFETs. These values correspond to 15 dB improvement in AVO_OTA and three fold enhancement in fT_OTA over a conventional non-underlap design. OTA performance based on underlap single gate SOI MOSFETs realized in ultra-thin body (UTB) and ultra-thin body BOX (UTBB) technologies is also evaluated. AVO_OTA values exhibited by a DG MOSFET-based OTA are 1.3-1.6 times higher as compared to a conventional UTB/UTBB single gate OTA. fT_OTA values for DG OTA are 10 GHz higher for UTB OTAs whereas a twofold improvement is observed with respect to UTBB OTAs. The simultaneous improvement in AVO_OTA and fT_OTA highlights the usefulness of underlap channel architecture in improving gain-bandwidth trade-off in analog circuit design. Underlap channel OTAs demonstrate high degree of tolerance to misalignment/oversize between front and back gates without compromising the performance, thus relaxing crucial process/technology-dependent parameters to achieve 'idealized' DG MOSFETs. Results show that underlap OTAs designed with a spacer-to-straggle (s/σ) ratio of 3.2 and operated below a bias current (IBIAS) of 80 µA demonstrate optimum performance. The present work provides new opportunities for realizing future ultra-wide band OTA design with underlap DG MOSFETs.

  4. 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.

  5. 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

  6. 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

  7. Seismic modeling of complex stratified reservoirs

    NASA Astrophysics Data System (ADS)

    Lai, Hung-Liang

    Turbidite reservoirs in deep-water depositional systems, such as the oil fields in the offshore Gulf of Mexico and North Sea, are becoming an important exploration target in the petroleum industry. Accurate seismic reservoir characterization, however, is complicated by the heterogeneous of the sand and shale distribution and also by the lack of resolution when imaging thin channel deposits. Amplitude variation with offset (AVO) is a very important technique that is widely applied to locate hydrocarbons. Inaccurate estimates of seismic reflection amplitudes may result in misleading interpretations because of these problems in application to turbidite reservoirs. Therefore, an efficient, accurate, and robust method of modeling seismic responses for such complex reservoirs is crucial and necessary to reduce exploration risk. A fast and accurate approach generating synthetic seismograms for such reservoir models combines wavefront construction ray tracing with composite reflection coefficients in a hybrid modeling algorithm. The wavefront construction approach is a modern, fast implementation of ray tracing that I have extended to model quasi-shear wave propagation in anisotropic media. Composite reflection coefficients, which are computed using propagator matrix methods, provide the exact seismic reflection amplitude for a stratified reservoir model. This is a distinct improvement over conventional AVO analysis based on a model with only two homogeneous half spaces. I combine the two methods to compute synthetic seismograms for test models of turbidite reservoirs in the Ursa field, Gulf of Mexico, validating the new results against exact calculations using the discrete wavenumber method. The new method, however, can also be used to generate synthetic seismograms for the laterally heterogeneous, complex stratified reservoir models. The results show important frequency dependence that may be useful for exploration. Because turbidite channel systems often display complex

  8. 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

  9. 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

  10. 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

  11. 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

  12. Tracking Changes in Maximal Oxygen Consumption with the Heart Rate Index in Female Collegiate Soccer Players

    PubMed Central

    Esco, Michael R.; Snarr, Ronald L.; Flatt, Andrew; Leatherwood, Matthew; Whittaker, Adam

    2014-01-01

    The purpose of this study was to determine if the HRindex Method (VO2max = [6 x HRindex – 5] x 3.5, where HRindex = HRmax/HRrest) was accurate for tracking changes in VO2max following 8-weeks of endurance training among collegiate female soccer players. Predicted VO2max via the HRindex Method and observed VO2max from a maximal exercise test on a treadmill were determined for a group of female soccer athletes (n = 15) before and following an 8-week endurance training protocol. The predicted (pVO2max) and observed (aVO2max) values were compared at baseline and within 1-week post-training. Change values (i.e., the difference between pre to post) for each variable were also determined and compared. There was a significant difference between aVO2max before (43.2 ± 2.8 ml·kg·min−1) and following (46.2 ± 2.1 ml·kg·min−1) the 8-week training program (p < 0.05). However, pVO2max did not significantly change following training (pre = 43.4 ± 4.6 ml·kg·min−1, post = 42.9 ± 4.1 ml·kg·min−1, p = 0.53). Furthermore, the correlation between the change in aVO2max and the change in pVO2max was trivial and non-significant (r = 0.30, p = 0.28). The HRindex Method does not appear to be suitable for predicting changes in VO2max following 8-weeks of endurance training in female collegiate soccer players. PMID:25414744

  13. 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

  14. 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.

  15. 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

    Summary: 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

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Wavelet dispersion and bright-spot detection

    SciTech Connect

    Luh, P.C.

    1989-03-01

    Since Ostrander in 1984 showed that the variations in reflectivity as a function of offset can be used for bright-spot validation, it has been known that these variations are often sensitive to errors in acquisition and processing of prestack seismic data. This presentation shows that even with perfect measurements, the bright-spot signal will be altered because the wavelet disperses as it propagates through an attenuating overburden. This in turn affects the slope term of the amplitude vs. offset (AVO) variation. For any single reflector, the dispersion of its propagated signal as a function of offset can be decomposed into a product of the vertical and horizontal dispersions. The vertical dispersion is the dispersion that a zero-offset arrival suffers through its propagation, and the horizontal dispersion is the additional dispersion that a nonzero-offset arrival must suffer further because of the residual normal moveout time. Numerical examples using a frequency-independent attenuation law show that even for a relatively high-Q or low-loss overburden, the horizontal dispersion alone can distort the AVO signal. This distortion cannot be taken care of by velocity analysis. A preferred method to overcome the dispersion effect would be to apply Q compensation on prestack seismic data before movement.

  8. Three-dimensional P-wave velocity structure and precise earthquake relocation at Great Sitkin Volcano, Alaska

    USGS Publications Warehouse

    Pesicek, Jeremy; Thurber, Clifford H.; DeShon, Heather R.; Prejean, Stephanie G.; Zhang, Haijiang

    2008-01-01

    Waveform cross-correlation with bispectrum verification is combined with double-difference tomography to increase the precision of earthquake locations and constrain regional 3D P-wave velocity heterogeneity at Great Sitkin volcano, Alaska. From 1999 through 2005, the Alaska Volcano Observatory (AVO) recorded ∼1700 earthquakes in the vicinity of Great Sitkin, including two ML 4.3 earthquakes that are among the largest events in the AVO catalog. The majority of earthquakes occurred during 2002 and formed two temporally and spatially separate event sequences. The first sequence began on 17 March 2002 and was centered ∼20 km west of the volcano. The second sequence occurred on the southeast flank of Great Sitkin and began 28 May 2002. It was preceded by two episodes of volcanic tremor. Earthquake relocations of this activity on the southeast flank define a vertical planar feature oriented radially from the summit and in the direction of the assumed regional maximum compressive stress due to convergence along the Alaska subduction zone. This swarm may have been caused or accompanied by the emplacement of a dike. Relocations of the mainshock–aftershock sequence occurring west of Great Sitkin are consistent with rupture on a strike-slip fault. Tomographic images support the presence of a vertically dipping fault striking parallel to the direction of convergence in this region. The remaining catalog hypocenters relocate along discrete features beneath the volcano summit; here, low P-wave velocities possibly indicate the presence of magma beneath the volcano.

  9. 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

  10. 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

  11. Free gas in Kumano forearc basin associated with methane hydrates and paleo-BSRs

    NASA Astrophysics Data System (ADS)

    Barnes, J.; Moore, G. F.

    2012-12-01

    anomalies, or bright spots, are DHIs observed in the seismic reflection data. These tend to be found within several chaotic packages beneath the BSR. Flat spots, thought to represent gas water contacts, are also observed, often in correlation with a phase change of bright horizons. Positive AVO (amplitude variation with offset) anomalies of the BSR and flat spots revealed in an amplitude analysis of the 3D survey also support the presence of free gas. The positive AVO anomaly and negative polarity of the BSR are consistent with a gas hydrate over gas interface; whereas the positive AVO anomaly combined with the positive polarity of the flat spots is consistent with gas water contacts.

  12. Development of Alaska Volcano Observatory Seismic Networks, 1988-2008

    NASA Astrophysics Data System (ADS)

    Tytgat, G.; Paskievitch, J. F.; McNutt, S. R.; Power, J. A.

    2008-12-01

    The number and quality of seismic stations and networks on Alaskan volcanoes have increased dramatically in the 20 years from 1988 to 2008. Starting with 28 stations on six volcanoes in 1988, the Alaska Volcano Observatory (AVO) now operates 194 stations in networks on 33 volcanoes spanning the 2000 km Aleutian Arc. All data are telemetered in real time to laboratory facilities in Fairbanks and Anchorage and recorded on digital acquisition systems. Data are used for both monitoring and research. The basic and standard network designs are driven by practical considerations including geography and terrain, access to commercial telecommunications services, and environmental vulnerability. Typical networks consist of 6 to 8 analog stations, whose data can be telemetered to fit on a single analog telephone circuit terminated ultimately in either Fairbanks or Anchorage. Towns provide access to commercial telecommunications and signals are often consolidated for telemetry by remote computer systems. Most AVO stations consist of custom made fiberglass huts that house the batteries, electronics, and antennae. Solar panels are bolted to the south facing side of the huts and the seismometers are buried nearby. The huts are rugged and have allowed for good station survivability and performance reliability. However, damage has occurred from wind, wind-blown pumice, volcanic ejecta, lightning, icing, and bears. Power is provided by multiple isolated banks of storage batteries charged by solar panels. Primary cells are used to provide backup power should the rechargable system fail or fall short of meeting the requirement. In the worst cases, snow loading blocks the solar panels for 7 months, so sufficient power storage must provide power for at least this long. Although primarily seismic stations, the huts and overall design allow additional instruments to be added, such as infrasound sensors, webcams, electric field meters, etc. Yearly maintenance visits are desirable, but some

  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. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Subglacial conditions at a sticky spot along Kamb Ice Stream, West Antarctica

    USGS Publications Warehouse

    Peters, L.E.; Anandakrishnan, S.

    2007-01-01

    We present the results of a seismic reflection experiment performed transverse to flow a few tens of kilometers above the main trunk of Kamb Ice Stream, West Antarctica, where we image a basal high surrounded by variable subglacial conditions. This high rises as much as 200 m above the surrounding bed, acting as a major sticking point that resists fast flow. Application of the amplitude variation with offset (AVO) seismic technique has highlighted regions of frozen sediments along our profile, suggesting that the ice stream is experiencing basal freeze-on in the region. The bedrock high appears to be at least partially draped in sediment cover, with a concentrated area of weak, dilatant till flanking one edge. This dilatant till is further dispersed along our profile, though it does not possess enough continuity to maintain streaming ice conditions. These results support the hypothesis that the ongoing shutdown of Kamb Ice Stream is due to a loss in continuous basal lubrication.

  13. 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.

  14. 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.

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

    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

  16. 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

  17. 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.

  18. Near-real-time volcanic ash cloud detection: Experiences from the Alaska Volcano Observatory

    NASA Astrophysics Data System (ADS)

    Webley, P. W.; Dehn, J.; Lovick, J.; Dean, K. G.; Bailey, J. E.; Valcic, L.

    2009-09-01

    Volcanic eruptions produce ash clouds, which are a major hazard to population centers and the aviation community. Within the North Pacific (NOPAC) region, there have been numerous volcanic ash clouds that have reached aviation routes. Others have closed airports and traveled for thousands of kilometers. Being able to detect these ash clouds and then provide an assessment of their potential movement is essential for hazard assessment and mitigation. Remote sensing satellite data, through the reverse absorption or split window method, is used to detect these volcanic ash clouds, with a negative signal produced from spectrally semi-transparent ash clouds. Single channel satellite is used to detect the early eruption spectrally opaque ash clouds. Volcanic Ash Transport and Dispersion (VATD) models are used to provide a forecast of the ash clouds' future location. The Alaska Volcano Observatory (AVO) remote sensing ash detection system automatically analyzes satellite data of volcanic ash clouds, detecting new ash clouds and also providing alerts, both email and text, to those with AVO. However, there are also non-volcanic related features across the NOPAC region that can produce a negative signal. These can complicate alerts and warning of impending ash clouds. Discussions and examples are shown of these non-volcanic features and some analysis is provided on how these features can be discriminated from volcanic ash clouds. Finally, there is discussion on how information of the ash cloud such as location, particle size and concentrations, could be used as VATD model initialization. These model forecasts could then provide an improved assessment of the clouds' future movement.

  19. 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.

  20. 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.

  1. 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.

  2. Surface layer determination for the Si spheres of the Avogadro project

    NASA Astrophysics Data System (ADS)

    Busch, I.; Azuma, Y.; Bettin, H.; Cibik, L.; Fuchs, P.; Fujii, K.; Krumrey, M.; Kuetgens, U.; Kuramoto, N.; Mizushima, S.

    2011-04-01

    For the accurate determination of the Avogadro constant, two 28Si spheres were produced, whose macroscopic density, in addition to other values, must be determined. To make a contribution to the new definition of the kilogram, a relative standard uncertainty of less than 2 × 10-8 has to be achieved. Each silicon surface is covered by a surface layer (SL). Consequently, correction parameters for the SL are determined to be applied to the mass and volume determination of the enriched spheres. With the use of a large set of surface analysing techniques, the structure of the SL is investigated. An unexpected metallic contamination existing on the sphere surface enlarges the uncertainty contribution of the correction parameters above the originally targeted value of 1 × 10-8. In the framework of this investigation this new obstacle is resolved in two ways. A new combination of analytical methods is applied to measure the SL mass mSL and the thickness dSL, including this new contamination, with an uncertainty of u(mSL) = 14.5 µg and 14.4 µg, respectively, and u(dSL) = 0.33 nm and 0.32 nm for the 28Si spheres AVO28-S5 and AVO28-S8, respectively. In the second part of the work, the chemical composition of these metallic contaminations is found to be Cu, Ni and Zn silicide compounds. For the removal of this contamination, a special procedure is developed, tested and applied to the spheres to produce the originally expected surface structure on the spheres. After the application of this new procedure the use of x-ray reflectometry directly at the spheres will be possible. It is expected to reduce the uncertainty contribution due to the SL down to 1 × 10-8.

  3. 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

  4. 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).

  5. 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.

  6. 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.

  7. Tracy Gas field, new shallow production

    SciTech Connect

    Sterling, R.; Nahama, R. )

    1991-02-01

    The Tracy Gas field was the first commercial gas production in California. Amerada Hess found production in the Cretaceous Tracy Formation in 1934. Five production wells ultimately produced 13 BCF by 1959. In 1989, Nahama and Weagant Energy Company (NWEC) purchased seismic data acquired by Shell Oil in 1980. The data was reprocessed for amplitude vs. offset (AVO) analysis. The data showed a bright spot at 1.0 section that exhibit an AVO response indicative of the presence of gas. Log data suggested the possibility of gas in the based Miocene Zilch Sands in the Amerada F.D.L. {number sign}4 well drilled in Sec. 15. T2S, R5E drilled in 1934. Husky Oil found gas production in the Zilch with the Rossi {number sign}1 well drilled in 1980. The most obvious problem with following up Husky's well was the J. M. Young Cordoza {number sign}1, a dry hole, that was misplotted on all of the commercially available base maps. Nahama and Weagant Energy Company drilled the Tracy 1-15 well in January 1990 directionally to test the Zilch sands in Sec. 15 almost exactly where the dry hole had been misplotted, resulting in a discovery of 48 net ft of pay in the Zilch. The Miocene gas is present in basal Zilch sands that were deposited unconformably on the Cretaceous Blewett Formation. The gas is located on the west flank of the Tracy anticline which is formed by a 90{degree} bend in the Vernalis fault, a thrust fault with over 1,600 ft of vertical movement. The Vernalis fault had movement as recently as the Pliocene, based on seismic data. Due to the relative youth of the fault, deeper potential in the Winters and Lathrop formations is believed not to exist on the Tracy anticline.

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. The 2007 Eruption of Pavlof Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    McNutt, S. R.

    2007-12-01

    Pavlof Volcano on the Alaska Peninsula began to erupt on August 15, 2007 after a 10.7 year repose. Precursor signals consisted of low-frequency earthquakes that began on August 14 and thermal anomalies that were likely coincident with the beginning of the eruption. The mainly strombolian eruptions are occurring from a new vent high on the SE flank of the volcano, separate from the NNE vent that had been active over the last several decades. Seismic activity, monitored by a network of 6 local instruments, consists of low-frequency events, explosion earthquakes, volcanic tremor, and lahar-generated signals. One station, PVV, is located only 220 m from a lahar channel, and lahars generate an easily distinguished high-frequency seismic signal. A commonly observed sequence is an increase in eruptive activity at the vent, accompanied by stronger tremor visible on all stations, and followed 12-30 minutes later by a lahar at PVV. This suggests that the eruption pulse ejects fresh hot material, which melts additional ice and snow to form new lahars. Steam and ash plumes have generally been below 15,000 ft, but rose as high as 20,000 ft on August 29 and 30. AVHRR remote sensing data showed an ash signal on these days, consistent with pilot reports. On August 30 lightning was observed in the plume from Cold Bay, 59 km SW. In response to the eruptions, AVO has been conducting 24 hr per day surveillance. Fieldwork to date has fortified seismic stations, and installed a new webcam, pressure sensor, and electric field meter. Collaborating scientists from the University of Alaska Fairbanks have installed aerosol sampling equipment at four locations, and collaborating scientists from New Mexico Tech have installed lightning detection equipment at four stations surrounding the volcano. Based on recent eruptions of Pavlof in 1981, 1986, 1996, etc., the eruptive activity is likely to last several months and may include one or more episodes of ash columns to heights of 30,000 ft or

  14. 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

  15. Haemodynamic interactions of medetomidine and the peripheral alpha-2 antagonist MK-467 during step infusions in isoflurane-anaesthetised dogs.

    PubMed

    Kaartinen, Johanna; del Castillo, Jérôme R E; Salla, Kati; Troncy, Eric; Raekallio, Marja R; Vainio, Outi M

    2014-11-01

    The haemodynamic interactions of a step infusion with medetomidine (MED) and the peripherally acting alpha-2 antagonist MK-467 (MK) were compared with MED infused alone in isoflurane-anaesthetised dogs. Eight purposely-bred Beagles were used in a randomised crossover study. Anaesthesia was induced with propofol intravenously (IV) and maintained with isoflurane in oxygen. Dogs received 1.25 µg/kg MED as a 1 min loading dose IV, along with a step-down MED infusion at rates of 8.0 µg/kg/h (step 1: 0-20 min), 5.5 µg/kg/h (step 2: 20-40 min) and 4.0 µg/kg/h (step 3: 40-95 min). Five minutes after starting the MED infusion, the dogs received MK-467 in a step-up infusion at rates of 100 µg/kg/h (step 1: 5-35 min), 200 µg/kg/h (step 2: 35-65 min) and 500 µg/kg/h (step 3: 65-95 min). Heart rate (HR), systolic (SAP) and mean arterial (MAP) blood pressures and arteriovenous oxygen content differences (a-vO2 diff) were calculated. Plasma drug concentrations were analysed. Repeated-measures general linear mixed models with Bonferroni correction were used for statistical analyses. MED infusion alone increased SAP maximally by 24.9%, MAP by 34.7% and a-vO2 diff by 222.5%, and reduced HR by 32.3%, but these changes were significantly attenuated by MK-467. Most MED effects returned to baseline during step 2 of MK-467 infusion and step 3 of MED infusion (MED/MK-467 ratio 1:18 to 1:50). Plasma concentrations of MED tended to be lower with the addition of MK-467. The use of step infusions helped to narrow down the therapeutic range for the MED/MK-467 infusion dose ratio during isoflurane anaesthesia in dogs.

  16. Parameter coupling in seismic reflection amplitudes and the importance of the number VP/VS=2

    NASA Astrophysics Data System (ADS)

    Innanen, K. A.

    2012-12-01

    Elastic plane wave displacement reflection coefficients may be calculated exactly as solutions of the Zoeppritz equations, or approximately using one of many linear forms such as that due to Aki and Richards. Most practical analysis involves interpretation of the slope and intercept of reflection strength vs. the square of the sine of the angle of incidence, in the context of the Aki-Richards approximation. Several authors (e.g., Castagna et al., 1998; Foster et al., 2010) have pointed out that slope and intercept interpretations, and relationships between various linear approximate solutions tend to become dramatically simplified under the "Wiggins approximation", when the VP/V_S ratio is 2. The theoretical origins of the importance of VP/V_S=2 do not appear to have been fully explored. We derive a certain series expansion of the solutions for the Zoeppritz equations about functions of angle and VP, VS and density ρ contrasts, whose first order terms are equivalent to those of the Aki-Richards approximation. The second order terms, which expose coupling between parameter contrasts in their determination of reflection coefficients, shed light on the importance of VP/V_S=2. Every nonzero term involving coupling with density is seen to be proportional to ( (VS)/(V_P) - (1)/(2). V_P/V_S=2 can therefore be understood as a special circumstance in which density is uncoupled from V_P and V_S$ over a larger than normal range of parameter contrast magnitudes. The uncoupling in turn reduces the ways reflection strengths can vary with contrasts, and thus we have a mathematical expectation of more simplified behaviour. The coupling/uncoupling of parameters can be examined directly in terms of contrasts across the elastic interface, or alternatively in terms of P-, S- and density reflectivities. Castagna, J. P., H. W. Swan and D. J. Foster, 1998, Framework for AVO gradient and intercept interpretation, Geophysics 63, 3, 948-956. Foster, D. J., R. G. Keys and F. D. Lane

  17. Physical properties of the top of the subducting Philippine Sea plate beneath the SW Japan arc, derived from onshore - offshore integrated seismic survey

    NASA Astrophysics Data System (ADS)

    Kurashimo, E.; Hirata, N.; Iwasaki, T.; Kodaira, S.; Kaneda, Y.

    2004-12-01

    The Nankai trough region, where the Philippine Sea Plate is subducting beneath the southwestern Japan arc, is a well-known seismogenic zone of interplate earthquakes (e.g. the 1944 Tonankai Earthquake (M=7.9) and the 1946 Nankai Earthquake (M=8.0)). A detailed crustal and upper mantle structure of the subducted Philippine Sea Plate and the overlying SW Japan arc is inevitably important to constrain the physical process of earthquake occurrence. In the summer of 1999, we conducted a highly dense onshore-offshore integrated seismic experiment in the eastern part of Shikoku Island and the adjacent Nankai trough, SW Japan. The most remarkable feature of the record sections is that extremely high amplitude reflections (bright reflections) can be recognized. This phase was interpreted as a reflected wave from the top of the subducting Philippine Sea plate at a depth of 18-30km (Kurashimo et al., 2002). Physical properties across the reflecting interface control amplitude versus offset (AVO) response. To obtain physical properties of the material between the subducting Philippine Sea plate and island arc crust, we investigated AVO response on this bright reflection. Analyzing this bright reflection, we could obtain the reflection coefficient (Rpp) as a function of the incident angle. Rpp tends to increase beyond about 50 degrees. To discuss about this characteristic, we calculated reflection coefficient for different velocity models. The single interface models (positive velocity contrast exists between the interface. negative velocity gradient exists upper side of the reflecter) can not explain the characteristic of the Rpp. Thin layer model (about 200 m) with a P-wave velocity of 4.0 km/s (a thin layer with a negative reflection coefficient at its upper boundary and a much larger, but positive reflection coefficient at its base exists) explains the characteristic of the Rpp. The P-wave velocity of the sediments shows 2.0-4.2km/s off Shikoku Island (Kodaira et al., 2002

  18. 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

  19. 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

  20. Cardiovascular response to exercise and training in the horse.

    PubMed

    Physick-Sheard, P W

    1985-08-01

    The quality of the overall response to exercise in the horse is very similar to that seen in man and laboratory animals; differences are mainly quantitative and persist when relative body weight is taken into account. The apparently greater flow capacity of the equine muscle bed during maximal whole-body exercise implicates the extent of central circulatory adaptations as the limiting factor in performance but implies a role for increase in arteriolar capacitance/muscle capillarity as an appropriate response to intense endurance training. The blood oxygen-carrying capacity of the horse is often quoted as the major component of the animal's superior aerobic work capacity, although the measured maximal a-vO2 for the horse is only 2 to 3 ml greater than that found in elite athletes. In fact, comparison of published performance data for man and the horse reveals that improved a-vO2 accounts for 23 per cent of the difference, and increased Qc accounts for the remaining 77 per cent of the superior oxygen consumption in the horse. The extent to which the horse can increase Qc and muscle blood flow appears to represent its major adaptations for maximal aerobic performance. It is frequently observed that there have been far greater improvements in human athletic performance than in that of the race-horse, and this difference is usually attributed to the application of scientific training methods to the athlete. It has also been suggested that the horse may have reached the limit of its adaptive ability. The horse has a maximal oxygen pulse of at least 0.6 ml per kg per beat compared with 0.35 for man, a 90 per cent whole body oxygen extraction, and an 80 to 90 per cent higher muscle blood flow, with an overall capability of increasing Vo2 max by 35 times. These represent levels that would appear to be difficult to improve upon. However, insufficient research has been performed to firmly state true maxima for the horse, and current research does not reveal to what extent the

  1. 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

  2. Autophagy inhibition enhances silibinin-induced apoptosis by regulating reactive oxygen species production in human prostate cancer PC-3 cells.

    PubMed

    Kim, Sang-Hun; Kim, Kwang-Youn; Yu, Sun-Nyoung; Park, Seul-Ki; Choi, Hyeun-Deok; Ji, Jae-Hoon; Ahn, Soon-Cheol

    Silibinin is a major bioactive component of silymarin and has anticancer effects on cancer cell line and has been used as a supportive therapy for chronic inflammatory liver condition. These anticancer effects of silibinin have been demonstrated both in vitro and in vivo cancer models. Although various evidences showed apoptosis signaling pathways by silibinin, there is no report to address the clearly mechanism of silibinin-induced autophagy in prostate cancer PC-3 cells. Our study showed that silibinin triggered autophagy through up-regulation of microtubule-associated protein 1 light chain 3 (LC3)-II, formation of acidic vesicular organelles (AVO) and punctuate of GFP-LC3, which was inhibited by 3-methyladenine (3-MA), an inhibitor of specific autophagy. In addition, silibinin induced autophagy through production of reactive oxygen species (ROS). Inhibition of ROS with diphenyleneiodonium (DPI), a ROS inhibitor, attenuated silibinin-triggered autophagy. Inhibition of autophagy with 3-MA enhanced the silibinin-induced apoptosis through the regulation of caspase-3 and PARP. These results suggested that silibinin induced autophagy by regulating ROS and its mechanism played a protective role against apoptosis in PC-3 cells.

  3. New insights into the North Taranaki Basin from New Zealand's first broadband 3D survey

    NASA Astrophysics Data System (ADS)

    Uzcategui, Marjosbet; Francis, Malcolm; Kong, Wai Tin Vincent; Patenall, Richard; Fell, Dominic; Paxton, Andrea; Allen, Tristan

    2016-06-01

    The Taranaki Basin is the only hydrocarbon producing basin in New Zealand. The North Taranaki Basin has widespread two-dimensional (2D) seismic coverage and numerous wells that have not encountered commercial accumulations. This is attributed to the structural complexity in the central graben and the absence of necessary information to help understand the basin's evolution. An active petroleum system has been confirmed by hydrocarbon shows and non-commercial oil and gas discoveries (Karewa-1 and Kora-1). A broadband long offset three-dimensional (3D) seismic survey was acquired and processed by Schlumberger in 2013 to evaluate the hydrocarbon potential of the North Taranaki Basin. Innovative acquisition techniques were combined with advanced processing and imaging methods. Raypath distortions and depth uncertainty were significantly reduced by processing through tilted transverse isotropy (TTI) anisotropic Kirchhoff prestack depth migration with a geologically constrained velocity model. The survey provided the necessary information to understand the petroleum system and provide evidence for material hydrocarbon accumulations. In this investigation, we assessed the hydrocarbon potential of the North Taranaki Basin using the newly acquired data. 3D seismic interpretation and amplitude-versus-offset (AVO) analysis support the renewed potential of the basin and demonstrate effectiveness of these technologies that together can achieve encouraging results for hydrocarbon exploration.

  4. [The upper-limits of deinstitutionalization not yet reached].

    PubMed

    Verbeek-Oudijk, D; Eggink, E

    2014-09-01

    The government aims at decreasing the number of elderly with disabilities in institutional care, and supplying them with homecare instead. This article provides starting points to identify the elderly for whom homecare is a realistic alternative to institutionalized care. Data from two Dutch surveys are used: the Amenities and Services Utilization Survey (AVO'07) and Elderly in Institutions (OII'08). We use a regression model that explains the use of care from several characteristics, and predict the probability to use a certain type of care for each individual. One ninth to a fifth of the elderly receiving institutional care have similar characteristics to homecare users. They are generally younger than other users of institutional care, attained higher educational levels, have higher incomes and have fewer disabilities. The prevalence of dementia is noticeably lower in this group. Domestic help, often in combination with personal care and nursing, is the most likely alternative for institutional care. Personal assistance may also prove to be an alternative, but could not be included in this research. However, there will always be a group of elderly that are more suitably and more efficiently cared for in an institutional setting. It is important that institutionalized care remains an option for this group. PMID:24980561

  5. 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

  6. 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.

  7. 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.

  8. Preliminary Rock Physics Characterization of Mississippian Carbonate Reservoir in Canada

    NASA Astrophysics Data System (ADS)

    Lee, M.; Keehm, Y.; Kim, H.

    2011-12-01

    The Mississippian formations in the Western Canada Sedimentary Basin are known to have large hydrocarbon resources. The Lodgepole formation is the most important reservoir for oil production in Daly and Virden fields. In this study, we performed preliminary reservoir characterization using rock physics modeling. We first delineated the Lodgepole formation by geological information, well-logs and core analysis data. Then, we conducted rock physics analyses such as GR-AI, DEM modeling, porosity-Vp, density-Vp, and porosity-permeability. We identified the Lodgepole formation has different porosity types, volume of shale, and the degree of fractures in difference intervals. In the upper part of the formation, we found that vuggy pores are well developed. Inter-particular porosity and fractures become significant as the depth increases. We found that the lower part can be divided into two groups by acoustic impedance. The prospective reservoir interval, one of the two groups, has higher fracture density, which can be identified by lower acoustic impedance. This result also implies that we could also use AVO analyses to delineate good reservoir intervals. In conclusion, rock physics modeling can be effectively applied to characterize the Lodgepole formation quantitatively with well-log and core analysis data. Acknowledgement: This work was supported by the Energy Resources R&D program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No. 2009201030001A).

  9. 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.

  10. EGCG synergizes the therapeutic effect of cisplatin and oxaliplatin through autophagic pathway in human colorectal cancer cells.

    PubMed

    Hu, Fen; Wei, Fei; Wang, Yulei; Wu, Bibo; Fang, Yuan; Xiong, Bin

    2015-05-01

    Application of the platinum-based chemotherapy for colorectal cancer is restricted due to its severe cytotoxic effects. In this study we used synergistic strategies by combining (-)-Epigallocatechin gallate (EGCG) with cisplatin or oxaliplatin to minimize the ill effects of platinum-based therapy. MTS assay was used to examine the effect of EGCG, cisplatin and oxaliplatin on the proliferation of human colorectal cancer DLD-1 and HT-29 cells. Autophagic process was evaluated by detection of LC3-II protein, autophagosome formation, and quantification of Acidic Vesicular. Treatment of DLD-1 and HT-29 cells with EGCG plus cisplatin or oxaliplatin showed a synergistic effect on inhibition of cell proliferation and induction of cell death. EGCG enhanced the effect of cisplatin and oxaliplatin-induced autophagy in DLD-1 and HT-29 cells, as characterized by the accumulation of LC3-II protein, the increase of acidic vesicular organelles (AVOs), and the formation of autophagosome. In addition, transfection of DLD-1 and HT-29 cells with siRNA against ATG genes reduced EGCG synergistic effect. Our findings suggest that combining EGCG with cisplatin or oxaliplatin could potentiate the cytotoxicity of cisplatin and oxaliplatin in colorectal cancer cells through autophagy related pathway.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Scattering characteristics in heterogeneously fractured reservoirs from waveform estimation

    NASA Astrophysics Data System (ADS)

    Shen, Feng; Toksöz, M. Nafi

    2000-02-01

    Offset-dependent characteristics of seismic scattering are useful for characterizing fractured reservoirs. We use two models that have different background medium properties and different azimuthal AVO responses to study elastic wave propagation and scattering in gas-saturated, heterogeneously fractured reservoirs. Heterogeneous fracture density distributions are built through stochastic modelling. Synthetic seismograms are generated by 3-D finite difference modelling, and waveforms along crack-normal and strike directions are considered in this paper. The multiple signal classification (MUSIC) frequency estimator is used in waveform estimation to provide frequency-domain attributes related to seismic wave scattering by fracture heterogeneity. Our results indicate that the strength of the scattering field is a function of the background medium. The strength also increases with increasing fracture scatterer density and with decreasing correlation length of spatial variations of fracture density. The scattering field is weak at the top of the fractured reservoir. The first-order results are dominated by velocity anisotropy of the mean fracture density field. However, the base of the fractured reservoir corresponds to a strong scattering field on which fracture heterogeneity has a larger effect and is characterized by the loss of coherence.

  16. 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.

  17. Huaier extract synergizes with tamoxifen to induce autophagy and apoptosis in ER-positive breast cancer cells

    PubMed Central

    Qi, Wenwen; Sun, Mingjuan; Kong, Xiangnan; Li, Yaming; Wang, Xiaolong; Lv, Shangge; Ding, Xia; Gao, Sumei; Cun, Jinjing; Cai, Chang; Wang, Xiaoting; Chen, Junfei; Yin, Aijun; Yang, Qifeng

    2016-01-01

    Tamoxifen (TAM) is the most widely used endocrine therapy for estrogen receptor (ER)-positive breast cancer patients, but side effects and the gradual development of insensitivity limit its application. We investigated whether Huaier extract, a traditional Chinese medicine, in combination with TAM would improve treatment efficacy in ER-positive breast cancers. MTT, colony formation, and invasion and migration assays revealed that the combined treatment had stronger anticancer effects than either treatment alone. Huaier extract enhanced TAM-induced autophagy, apoptosis, and G0/G1 cell cycle arrest, as measured by acidic vesicular organelle (AVO) staining, TUNEL, flow cytometry, and western blot. Additionally, combined treatment inhibited tumorigenesis and metastasis by suppressing the AKT/mTOR signaling pathway. Huaier extract also enhanced the inhibitory effects of TAM on tumor growth in vivo in a xenograft mouse model. These results show that Huaier extract synergizes with TAM to induce autophagy and apoptosis in ER-positive breast cancer cells by suppressing the AKT/mTOR pathway. PMID:27027343

  18. 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.

  19. 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

  20. The novel pterostilbene derivative ANK-199 induces autophagic cell death through regulating PI3 kinase class III/beclin 1/Atg‑related proteins in cisplatin‑resistant CAR human oral cancer cells.

    PubMed

    Hsieh, Min-Tsang; Chen, Hao-Ping; Lu, Chi-Cheng; Chiang, Jo-Hua; Wu, Tian-Shung; Kuo, Daih-Huang; Huang, Li-Jiau; Kuo, Sheng-Chu; Yang, Jai-Sing

    2014-08-01

    Pterostilbene is an effective chemopreventive agent against multiple types of cancer cells. A novel pterostilbene derivative, ANK-199, was designed and synthesized by our group. Its antitumor activity and mechanism in cisplatin-resistant CAR human oral cancer cells were investigated in this study. Our results show that ANK-199 has an extremely low toxicity in normal oral cell lines. The formation of autophagic vacuoles and acidic vesicular organelles (AVOs) was observed in the ANK-199-treated CAR cells by monodansylcadaverine (MDC) and acridine orange (AO) staining, suggesting that ANK-199 is able to induce autophagic cell death in CAR cells. Neither DNA fragmentation nor DNA condensation was observed, which means that ANK-199-induced cell death is not triggered by apoptosis. In accordance with morphological observation, 3-MA, a specific inhibitor of PI3K kinase class III, can inhibit the autophagic vesicle formation induced by ANK-199. In addition, ANK-199 is also able to enhance the protein levels of autophagic proteins, Atg complex, beclin 1, PI3K class III and LC3-II, and mRNA expression of autophagic genes Atg7, Atg12, beclin 1 and LC3-II in the ANK-199-treated CAR cells. A molecular signaling pathway induced by ANK-199 was therefore summarized. Results presented in this study show that ANK-199 may become a novel therapeutic reagent for the treatment of oral cancer in the near future (patent pending).

  1. 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

  2. 3-D Numerical Modeling of a Complex Salt Structure

    SciTech Connect

    House, L.; Larsen, S.; Bednar, J.B.

    2000-02-17

    Reliably processing, imaging, and interpreting seismic data from areas with complicated structures, such as sub-salt, requires a thorough understanding of elastic as well as acoustic wave propagation. Elastic numerical modeling is an essential tool to develop that understanding. While 2-D elastic modeling is in common use, 3-D elastic modeling has been too computationally intensive to be used routinely. Recent advances in computing hardware, including commodity-based hardware, have substantially reduced computing costs. These advances are making 3-D elastic numerical modeling more feasible. A series of example 3-D elastic calculations were performed using a complicated structure, the SEG/EAGE salt structure. The synthetic traces show that the effects of shear wave propagation can be important for imaging and interpretation of images, and also for AVO and other applications that rely on trace amplitudes. Additional calculations are needed to better identify and understand the complex wave propagation effects produced in complicated structures, such as the SEG/EAGE salt structure.

  3. 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.

  4. Improved vehicle occupancy data collection methods. Final report, 1994--1997

    SciTech Connect

    Heidtman, K.; Skarpness, B.; Tornow, C.

    1997-12-31

    The report evaluates current and emerging vehicle occupancy data collection methodologies. Five primary methods for collecting vehicle occupancy data were identified: the traditional roadside/windshield observation method, a recently developed carousel observational method, photographic surveillance, mail-out or telephone surveys, and accident database extraction method. The findings show that other methods besides the traditional windshield method may be advantageous for collecting vehicle occupancy information. The key factors in selecting a collection method are the conditions under which vehicle occupancy is to be estimated. For example, the accident method and mail-out surveys are well suited for developing regional vehicle occupancy estimates, while the windshield method and carousel method are well suited for corridor-specific estimates. Another key finding, which impact the selection of a method and sampling period, is the fact that average vehicle occupancy estimates vary significantly by time-of-day, day-of-week, and month-of-year. The implications of this finding is that agencies cannot continue to infer yearly AVO estimates from data collected during a limited time period such as the morning rush hour period. Recommendations for selecting and implementing a vehicle occupancy data collection method are also provided.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Inhibition of autophagy by chloroquine potentiates synergistically anti-cancer property of artemisinin by promoting ROS dependent apoptosis.

    PubMed

    Ganguli, Arnab; Choudhury, Diptiman; Datta, Satabdi; Bhattacharya, Surela; Chakrabarti, Gopal

    2014-12-01

    Artemisinin (ART) is a well-known anti-malarial drug, and recently it is shown prospective to selectively kill cancer cells. But low potency makes it inappropriate for use as an anticancer drug. In this study, we modulated the ART-induced autophagy to increase Potency of ART as an anticancer agent. ART reduced the cell viability and colony forming ability of non-small lung carcinoma (A549) cells and it was non-toxic against normal lung (WI38) cells. ART induced autophagy at the early stage of treatment. Pre-treatment with chloroquine (CQ) and followed by ART treatment had synergistic combination index (CI) for cell death. Inhibition of autophagy by CQ pre-treatment led to accumulation of acidic vacuoles (AVOs) which acquainted with unprocessed damage mitochondria that subsequently promoted ROS generation, and resulted releases of Cyt C in cytosol that caused caspase-3 dependent apoptosis cell death in ART-treated A549 cells. Scavenging of ROS by antioxidant N-acetyl-cysteine (NAC) inhibited caspase-3 activity and rescued the cells from apoptosis. Similar effects were observed in other cancer cells SCC25 and MDA-MB-231. The appropriate manipulation of autophagy by using CQ provides a powerful strategy to increase the Potency of selective anticancer property of ART. PMID:25308836

  10. Imaging the Subduction Decollement, Hikurangi Subduction Zone, New Zealand

    NASA Astrophysics Data System (ADS)

    Bannister, S.; Toulmin, S.; Henrys, S.; Reyners, M.; Barker, D.; Pecher, I.; Sutherland, R.; Uruski, C.; Maslen, G.

    2006-12-01

    Beneath the eastern coastline of North Island, New Zealand, the subducted Pacific plate dips at less than 3 degrees to the northwest and the subduction decollement is at a depth of less than 15-km. The active-source NIGHT and passive-source CNIPSE experiments carried out in 2001 image the shallow dipping decollement down to more than 6 s (twt) at which point it steepens landward, 120 km from the Hikurangi trench. This change in dip appears to be closely associated with the onset of seismogenesis in the subducted plate. Velocity inversion of CNIPSE earthquake times reveals the forearc to be a relatively low Vp (<5.5 km/s), high Vp/Vs (>1.85), high Poisson's ratio (>0.29) region overlying the 12-15 km thick subducted crust. In March-May 2005 a new industry-seismic survey, 05CM, was carried out offshore the east coast, seismically imaging the subducted plate. More than 278000 airgun shots were also recorded by temporary seismometer stations placed along the coastline, out to offsets of more than 100 km. The combined marine and offshore- onshore seismic data highlight an area of more than 400 sq.kms. with higher reflectivity on the subduction decollement up-dip of the up-dip limit of seismogenesis, which we further examine using AVO and finite- difference modelling.

  11. 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.

  12. 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.

  13. 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

  14. Investigating Geothermal Activity, Volcanic Systems, and Deep Tectonic Tremor on Akutan Island, Alaska, with Array Seismology

    NASA Astrophysics Data System (ADS)

    Haney, M. M.; Prejean, S. G.; Ghosh, A.; Power, J. A.; Thurber, C. H.

    2012-12-01

    In addition to hosting one of the most active volcanoes in the Aleutian Arc, Akutan Island, Alaska, is the site of a significant geothermal resource within Hot Springs Bay Valley (HSBV). We deployed 15 broadband (30 s to 50 Hz) seismometers in and around HSBV during July 2012 as part of an effort to establish a baseline for background seismic activity in HSBV prior to geothermal production on the island. The stations recorded data on-site and were retrieved in early September 2012. Additional targets for the array include the tracking of deep tectonic tremor known to occur within the Aleutian subduction zone and the characterization of volcano-tectonic (VT) and deep long period (DLP) earthquakes from Akutan Volcano. Because 13 of the stations in the array sit within an area roughly 1.5 km by 1.5 km, we plan to apply methods based on stacking and beamforming to analyze the waveforms of extended signals lacking clear phase arrivals (e.g., tremor). The average spacing of the seismometers, roughly 350 m, provides sensitivity to frequencies between 2-8 Hz. The stacking process also increases the signal-to-noise ratio of small amplitude signals propagating across the array (e.g., naturally occurring geothermal seismicity). As of August 2012, several episodes of tectonic tremor have been detected in the vicinity of Akutan Island during the array deployment based on recordings from nearby permanent stations operated by the Alaska Volcano Observatory (AVO). This is the first small-aperture array deployed in the Aleutian Islands and the results should serve as a guide for future array deployments along the Aleutian Arc as part of the upcoming EarthScope and GeoPRISMS push into Alaska. We demonstrate the power of array methods based on stacking at Akutan Volcano using a sequence of DLP earthquakes from June 11, 2012 that were recorded on the permanent AVO stations. We locate and characterize the lowest frequency portion of the signals at 0.5 Hz. At these low frequencies, the

  15. [Myoelectric function, metabolism, intestinal circulation and vagal activity after chemical sympathectomy].

    PubMed

    Obuchowicz, Rafał; Sendur, Ryszard; Pawlik, Michał; Biernat, Jarosław; Koprowska, Bernadetta; Jaworek, Jolanta; Thor, Piotr J

    2002-01-01

    Adrenergic innervation plays an important role in the control of electric activity and circulatory parameters of the gut. Importance of adrenergic system as a modulator of motor, neural and metabolic activity of the intestine is studied extensively but still not well understood. We use 6-OHDA a neurotoxin and a blocking agent of adrenergic fibers, to evaluate their exact role in the control of vital parameters of the intestine and vagal nerves. 50 Wistar rats were used. Animals were fasted 24 h prior to experiment with free access to water allowed. Acute experiments were performed on 30 rats, divided in the three groups. Four experimental groups were established. I--sham operated. II and III--pretreated with 6-ODHA (25 mg//kg/24 h s.c.) 3 days before experiment. IV group were used for chronic procedure. Thiopental anesthesia (Vetbutal Biovet) was applied. Animals were artificially ventilated with positive pressure rodent ventilator (Ugo Basile), and heated with continuous temperature control by rectal thermistor (FST). Left carotid artery was cannulated and connected with electro manometer--arterial pressure (AP) was expressed in mm Hg. Right jugular vein was cannulated for continuous saline administration 0.2 ml/h. Mesenteric blood flow (MBF) was recorded with use of ultrasonic probe (Transonic systems T206). Microcirculatory blood Flow (LDBF) was estimated by laser Doppler flowmetry (Periflux 2001 Master). Arterio-venous difference (AVO2) was estimated from whole blood (AVOXimeter 1000 E). Oxygen uptake was calculated from MBF and AVO2 and expressed in ml/min/100 g tissue. Chronic experiments were performed on conscious animals with electrodes implanted to the serosal surface of the intestinal wall. Measurements of intestinal myoelectric parameters were performed one, two and three weeks after 6-OHDA administration. Vagal activity was recorded in left vagus nerve in the neck with suction electrodes (one month after 6-OHDA). 6-OHDA pretreatment evoked increase of

  16. 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

  17. Significance of the basin wide reverse polarity reflector in the Offshore Sydney Basin, East Australian Margin

    NASA Astrophysics Data System (ADS)

    Rahman Talukder, Asrarur; Nadri, Dariush; Rajput, Sanjeev; Clennell, Ben; Griffiths, Cedric; Breeze, David

    2010-05-01

    changes laterally and is characterized by patches of high amplitude (bright spots). Contour mapping shows that this reverse polarity reflector is continuous and regionally distributed. The depth of the reflector with respect to the sea surface is too shallow to be a BSR, typically caused at the interface between hydrate containing sediments above and free gas below. Reverse polarity is a common indicator of the accumulation of hydrocarbons. However, alternatively in such shallow depth it can also be caused by the presence of a soft sediment layer. Another important point to note is that no chimney or any other gas escape features have been observed in the vicinity originating from the reverse polarity reflector. However, in the adjacent continental slope, giant pockmarks have been observed on the bathymetry data. They most probably originated from gas sources in Permian coal measures. In order to understand what is causing this reverse polarity further quantitative analysis such as AVO and inversion has been done. AVO analysis and subsequent inversion of selected seismic lines show that some parts of the reversed polarity are characterized by bright spots, especially on the hanging wall side of the major faults, caused by the presence of gas. The stratigraphic position of the reflector suggests that the anomalous horizon could have been formed during the low-stand that followed the high-stand progradation event seen on dip sections. The gas accumulation could then be associated with "back reef" carbonates that during the low stand have been subjected to karstification causing the gas entrapment in vugular pore spaces.

  18. 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

  19. 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

  20. Tetrandrine induces cell death in SAS human oral cancer cells through caspase activation-dependent apoptosis and LC3-I and LC3-II activation-dependent autophagy.

    PubMed

    Huang, An-Cheng; Lien, Jin-Cherng; Lin, Meng-Wei; Yang, Jai-Sing; Wu, Ping-Ping; Chang, Shu-Jen; Lai, Tung-Yuan

    2013-08-01

    Numerous studies have demonstrated that autophagy is associated with cancer development. Thus, agents to induce autophagy could be employed in some cases for the treatment of cancer. Our results showed that tetrandrine significantly decreased the viability of SAS cells in a concentration- and time-dependent manner. Tetrandrine induced nuclear condensation, demonstrated by DAPI staining. The early events in apoptosis analysed by Annexin V/PI staining indicated that the percentage of cells staining positive for Annexin V was slightly increased in SAS cells with tetrandrine treatment but was much lower following bafilomycin A1 pre-treatment. Tetrandrine caused AVO and MDC induction in SAS cells in a concentration-dependent manner by fluorescence microscopy. Tetrandrine also caused LC-3 expression in SAS cells in a time-dependent manner. Our results show that tetrandrine treatment induced the levels of cleaved caspase-3 in a concentration- and time-dependent manner. Tetrandrine treatment induced the levels of LC-3 II, Atg-5, beclin-1, p-S6, p-ULK, p-mTOR, p-Akt (S473) and raptor. Tetrandrine decreased cell viability, but bafilomycin A1, 3-MA, chloroquine and NAC protected tetrandrine-treated SAS cells against decrease of cell viability. Atg-5, beclin-1 siRNA decreased tetrandrine-induced cleaved caspase-3 and cleaved PARP in SAS cells and protected tetrandrine-treated SAS cells against decrease in cell viability. Chloroquine, NAC and bafilomycin A1 also decreased tetrandrine-induced cleaved caspase-3 and cleaved PARP in SAS cells. Our results indicate the tetrandrine induces apoptosis and autophagy of SAS human cancer cells via caspase-dependent and LC3-I and LC3-II‑dependent pathways.

  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. 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.

  3. 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

  4. An Algorithm for Evaluating Fresnel-Zone Textural Roughness for Seismic Facies Interpretation

    NASA Astrophysics Data System (ADS)

    Di, H.; Gao, D.

    2014-12-01

    In reflection seismic interpretation, a 1-D convolutional model is commonly used to interpret amplitude variations based on the geometric ray theory assuming seismic wave to reflect at a reflection point; however, the propagation of seismic waves actually occurs in a finite zone around the geometric ray path and gets reflected from a zone known as Fresnel zone. The collected signal at the surface turns out to be the superposition of reflections from within the Fresnel zone, which is a function of texture. Generally, for a rough texture such as sandstone, the dominant reflection is from the zone margin, while for a smooth texture such as marine shale, the dominant reflection is from the zone center. Based on this concept, Fresnel-zone texture directly affects amplitude variations with offset (AVO), azimuth (AVAZ), and frequency (AVF). Here we develop a computer algorithm for evaluating Fresnel-zone textural roughness. The algorithm starts with dividing the Fresnel zone into a set of micro-zones. It then builds an initial texture model to be convolved with an extracted wavelet. By comparing the synthetic signal from a Fresnel zone to the real seismic signal within an analysis window at a target location, the model is adjusted and updated until both synthetic and real signals match best. The roughness is evaluated as the correlation coefficient between the generated texture model within the Fresnel zone and the ideal model for a rough texture medium. Our new algorithm is applied to a deep-water 3D seismic volume over offshore Angola, west Africa. The results show that a rough texture is associated with channel sands, whereas a smooth texture with marine shale.

  5. Downregulation of KDM4A Suppresses the Survival of Glioma Cells by Promoting Autophagy.

    PubMed

    Wang, Bo; Fan, Xinxin; Ma, Chong; Lei, Hui; Long, Qianfa; Chai, Yuan

    2016-10-01

    Glioma is the most common type of primary intracranial tumor and has a poor prognosis. It has been reported that lysine-specific demethylase 4A (KDM4A) can promote tumor progression; however, its role in human glioma remains unclear. Western blot and qRT-PCR analyses showed that KDM4A was highly expressed in U87MG and T98G cells. 48 h after transfection with siKDM4A, the protein level of KDM4A was significantly downregulated. The silenced expression of KDM4A in T98G or U87MG cells inhibited cell viability and invasion, and aggravated cell apoptosis. We found that the siKDM4A led to a significant increase in acidic vesicular organelles (AVOs) and upregulated the expression of autophagy-related proteins, including LC3B-phosphatidylethanolamine conjugate, a cytosolic form of LC3B (LC3B-II/LC3B-I) and Beclin 1 in T98G and U87MG cells. Further studies demonstrated that after pretreatment with 3-MA (3 mmol/L) for 48 h, siKDM4A-transfected cells showed a prominent decrease in LC3B-II/LC3B-I and Beclin 1, accompanied by increased viability and invasion and decreased apoptosis. Our results suggest that the inhibition of KDM4A expression might efficiently suppress glioma cell survival by promoting autophagy, providing a promising agent for treating malignant gliomas. PMID:27514525

  6. 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

  7. 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.

  8. Reconstruction of Signaling Networks Regulating Fungal Morphogenesis by Transcriptomics▿ †

    PubMed Central

    Meyer, Vera; Arentshorst, Mark; Flitter, Simon J.; Nitsche, Benjamin M.; Kwon, Min Jin; Reynaga-Peña, Cristina G.; Bartnicki-Garcia, Salomon; van den Hondel, Cees A. M. J. J.; Ram, Arthur F. J.

    2009-01-01

    Coordinated control of hyphal elongation and branching is essential for sustaining mycelial growth of filamentous fungi. In order to study the molecular machinery ensuring polarity control in the industrial fungus Aspergillus niger, we took advantage of the temperature-sensitive (ts) apical-branching ramosa-1 mutant. We show here that this strain serves as an excellent model system to study critical steps of polar growth control during mycelial development and report for the first time a transcriptomic fingerprint of apical branching for a filamentous fungus. This fingerprint indicates that several signal transduction pathways, including TORC2, phospholipid, calcium, and cell wall integrity signaling, concertedly act to control apical branching. We furthermore identified the genetic locus affected in the ramosa-1 mutant by complementation of the ts phenotype. Sequence analyses demonstrated that a single amino acid exchange in the RmsA protein is responsible for induced apical branching of the ramosa-1 mutant. Deletion experiments showed that the corresponding rmsA gene is essential for the growth of A. niger, and complementation analyses with Saccharomyces cerevisiae evidenced that RmsA serves as a functional equivalent of the TORC2 component Avo1p. TORC2 signaling is required for actin polarization and cell wall integrity in S. cerevisiae. Congruently, our microscopic investigations showed that polarized actin organization and chitin deposition are disturbed in the ramosa-1 mutant. The integration of the transcriptomic, genetic, and phenotypic data obtained in this study allowed us to reconstruct a model for cellular events involved in apical branching. PMID:19749177

  9. 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.

  10. 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.

  11. Immunomodulatory Protein from Ganoderma microsporum Induces Pro-Death Autophagy through Akt-mTOR-p70S6K Pathway Inhibition in Multidrug Resistant Lung Cancer Cells.

    PubMed

    Chiu, Ling-Yen; Hu, Ming-E; Yang, Tsung-Ying; Hsin, I-Lun; Ko, Jiunn-Liang; Tsai, Kan-Jen; Sheu, Gwo-Tarng

    2015-01-01

    Chemoresistance in cancer therapy is an unfavorable prognostic factor in non-small cell lung cancer (NSCLC). Elevation of intracellular calcium level in multidrug resistant (MDR) sublines leads to sensitization of MDR sublines to cell death. We demonstrated that a fungal protein from Ganoderma microsporum, GMI, elevates the intracellular calcium level and reduces the growth of MDR subline via autophagy and apoptosis, regardless of p-glycoprotein (P-gp) overexpression, in mice xenograft tumors. In addition, we examined the roles of autophagy in the death of MDR A549 lung cancer sublines by GMI, thapsigargin (TG) and tunicamycin (TM) in vitro. Cytotoxicity of TG was inhibited by overexpressed P-gp. However, TM-induced death of MDR sublines was independent of P-gp level. Combinations of TG and TM with either docetaxel or vincristine showed no additional cytotoxic effects on MDR sublines. TG- and TM-mediated apoptosis of MDR sublines was demonstrated on Annexin-V assay and Western blot and repressed by pan-caspase inhibitor (Z-VAD-FMK). Treatment of MDR sublines with TG and TM also augmented autophagy with accumulation of LC3-II proteins, breakdown of p62 and formation of acidic vesicular organelles (AVOs). Inhibition of ATG5 by shRNA silencing significantly reduced autophagy and cell death but not apoptosis following TG or TM treatment. GMI treatment inhibited the phosphorylation of Akt/S473 and p70S6K/T389. Interestingly, the phosphorylation of ERK was not associated with GMI-induced autophagy. We conclude that autophagy plays a pro-death role in acquired MDR and upregulation of autophagy by GMI via Akt/mTOR inhibition provides a potential strategy for overcoming MDR in the treatment of lung cancers.

  12. Induction of Endoplasmic Reticulum Stress Response by the Indole-3-Carbinol Cyclic Tetrameric Derivative CTet in Human Breast Cancer Cell Lines

    PubMed Central

    Galluzzi, Luca; De Santi, Mauro; Crinelli, Rita; De Marco, Cinzia; Zaffaroni, Nadia; Duranti, Andrea; Brandi, Giorgio; Magnani, Mauro

    2012-01-01

    Background Indole-3-carbinol and its metabolic products are considered promising chemopreventive and anticancer agents. Previously we have shown that the indole-3-carbinol cyclic tetrameric derivative CTet induces autophagy and inhibits cell proliferation via inhibition of Akt activity and overexpression of p21/CDKN1A and GADD45A, in both estrogen receptor-positive (MCF-7) and triple negative (MDA-MB-231) breast cancer cell lines. In the present study, we further characterize the autophagic response and investigate the mechanism through which CTet regulates these events. Methodology/Principal Findings Analysis of gene expression microarray data and subsequent confirmation by quantitative real-time PCR, showed that CTet is able to induce up-regulation of key signaling molecules involved in endoplasmic reticulum (ER) stress response (e.g. DDIT3/CHOP, CHAC1, ATF3, HSPA5/BiP/GRP78, CEBPB, ASNS) and autophagy (e.g. MAP1LC3B), in both MCF-7 and MDA-MB-231 cell lines. Moreover, the monitoring of Xbp-1 splicing confirmed the activation of IRE1/Xbp-1 ER stress response branch after CTet treatment. The role of autophagic processes (known to be induced by ER stress) was investigated further through ATG5 gene silencing and pharmacological inhibition of AVOs formation. CTet was shown to induce an autophagy-related cell death. Moreover, CTet-treated cells stained with Hoechst/PI revealed the presence of necrotic processes without evidence of apoptosis. Conclusions/Significance The ER stress response was identified as the main upstream molecular mechanism through which CTet acts in both hormone-responsive and triple-negative breast cancer cells. Because of its important role in cancer development, ER stress is a potential target in cancer therapy. The abiltiy of CTet to induce ER stress response and subsequently activate a death program in tumor cells confirms this molecule as a promising anticancer agent. PMID:22905241

  13. Volcano Monitoring Using Google Earth

    NASA Astrophysics Data System (ADS)

    Cameron, W.; Dehn, J.; Bailey, J. E.; Webley, P.

    2009-12-01

    At the Alaska Volcano Observatory (AVO), remote sensing is an important component of its daily monitoring of volcanoes. AVO’s remote sensing group (AVORS) primarily utilizes three satellite datasets; Advanced Very High Resolution Radiometer (AVHRR) data, from the National Oceanic and Atmospheric Administration’s (NOAA) Polar Orbiting Satellites (POES), Moderate Resolution Imaging Spectroradiometer (MODIS) data from the National Aeronautics and Space Administration’s (NASA) Terra and Aqua satellites, and NOAA’s Geostationary Operational Environmental Satellites (GOES) data. AVHRR and MODIS data are collected by receiving stations operated by the Geographic Information Network of Alaska (GINA) at the University of Alaska’s Geophysical Institute. An additional AVHRR data feed is supplied by NOAA’s Gilmore Creek satellite tracking station. GOES data are provided by the Naval Research Laboratory (NRL), Monterey Bay. The ability to visualize these images and their derived products is critical for the timely analysis of the data. To this end, AVORS has developed javascript web interfaces that allow the user to view images and metadata. These work well for internal analysts to quickly access a given dataset, but they do not provide an integrated view of all the data. To do this AVORS has integrated its datasets with Keyhole Markup Language (KML) allowing them to be viewed by a number of virtual globes or other geobrowsers that support this code. Examples of AVORS’ use of KML include the ability to browse thermal satellite image overlays to look for signs of volcanic activity. Webcams can also be viewed interactively through KML to confirm current activity. Other applications include monitoring the location and status of instrumentation; near real-time plotting of earthquake hypocenters; mapping of new volcanic deposits using polygons; and animated models of ash plumes, created by a combination of ash dispersion modeling and 3D visualization packages.

  14. Transversely isotropic elasticity and poroelasticity arising from thin isotropic layers

    SciTech Connect

    Berryman, J.G.

    1997-07-01

    Since the classic work of Postma [1955] and Backus [1962], much has been learned about elastic constants in vertical transversely isotropic (VTI) media when the anisotropy is due to fine layering of isotropic elastic materials. However, new results are still being discovered. For example, the P-wave anisotropy parameter c{sub 11}/c{sub 33} lies in the range 1/4 {<=} c{sub 11}/c{sub 33} {<=} <{lambda}+2{mu}><1/({lambda}+2{mu})>, when the layers are themselves composed of isotropic elastic materials with Lame constants {lambda} and {mu} and the vertical average of the layers is symbolized by <{center_dot}>. The lower bound corrects a result of Postma. For porous layers, a connected solid frame forms the basis of the elastic behavior of a poroelastic medium in the presence of confining forces, while connected pores permit a percolating fluid (if present) to influence the mechanical response of the system from within. For isotropic and anisotropic poroelastic media, we establish general formulas for the behavior of transversely isotropic poroelasticity arising from laminations of isotropic components. The Backus averaging method is shown to provide elementary means of constructing general formulas. The results for confined fluids are then compared with the more general Gassmann [1951] formulas that must be satisfied by any anisotropic poroelastic medium and found to be in complete agreement. Such results are important for applications to oil exploration using AVO (amplitude versus offset) since the presence or absence of a fluid component, as well as the nature of the fluid, is the critical issue and the ways in which the fluid influences seismic reflection data still need to be better understood.

  15. Hemodynamic responses to heat stress in the resting and exercising human leg: insight into the effect of temperature on skeletal muscle blood flow

    PubMed Central

    Pearson, James; Low, David A.; Stöhr, Eric; Kalsi, Kameljit; Ali, Leena; Barker, Horace

    2011-01-01

    Heat stress increases limb blood flow and cardiac output (Q̇) in humans, presumably in sole response to an augmented thermoregulatory demand of the skin circulation. Here we tested the hypothesis that local hyperthermia also increases skeletal muscle blood flow at rest and during exercise. Hemodynamics, blood and tissue oxygenation, and muscle, skin, and core temperatures were measured at rest and during exercise in 11 males across four conditions of progressive whole body heat stress and at rest during isolated leg heat stress. During whole body heat stress, leg blood flow (LBF), Q̇, and leg (LVC) and systemic vascular conductance increased gradually with elevations in muscle temperature both at rest and during exercise (r2 = 0.86–0.99; P < 0.05). Enhanced LBF and LVC were accompanied by reductions in leg arteriovenous oxygen (a-vO2) difference and increases in deep femoral venous O2 content and quadriceps tissue oxygenation, reflecting elevations in muscle and skin perfusion. The increase in LVC occurred despite an augmented plasma norepinephrine (P < 0.05) and was associated with elevations in muscle temperature (r2 = 0.85; P = 0.001) and arterial plasma ATP (r2 = 0.87; P < 0.001). Isolated leg heat stress accounted for one-half of the increase in LBF with severe whole body heat stress. Our findings suggest that local hyperthermia also induces vasodilatation of the skeletal muscle microvasculature, thereby contributing to heat stress and exercise hyperemia. The increased limb muscle vasodilatation in these conditions of elevated muscle sympathetic vasoconstrictor activity is closely related to the rise in arterial plasma ATP and local tissue temperature. PMID:21178127

  16. The New USGS Volcano Hazards Program Web Site

    NASA Astrophysics Data System (ADS)

    Venezky, D. Y.; Graham, S. E.; Parker, T. J.; Snedigar, S. F.

    2008-12-01

    The U.S. Geological Survey's (USGS) Volcano Hazard Program (VHP) has launched a revised web site that uses a map-based interface to display hazards information for U.S. volcanoes. The web site is focused on better communication of hazards and background volcano information to our varied user groups by reorganizing content based on user needs and improving data display. The Home Page provides a synoptic view of the activity level of all volcanoes for which updates are written using a custom Google® Map. Updates are accessible by clicking on one of the map icons or clicking on the volcano of interest in the adjacent color-coded list of updates. The new navigation provides rapid access to volcanic activity information, background volcano information, images and publications, volcanic hazards, information about VHP, and the USGS volcano observatories. The Volcanic Activity section was tailored for emergency managers but provides information for all our user groups. It includes a Google® Map of the volcanoes we monitor, an Elevated Activity Page, a general status page, information about our Volcano Alert Levels and Aviation Color Codes, monitoring information, and links to monitoring data from VHP's volcano observatories: Alaska Volcano Observatory (AVO), Cascades Volcano Observatory (CVO), Long Valley Observatory (LVO), Hawaiian Volcano Observatory (HVO), and Yellowstone Volcano Observatory (YVO). The YVO web site was the first to move to the new navigation system and we are working on integrating the Long Valley Observatory web site next. We are excited to continue to implement new geospatial technologies to better display our hazards and supporting volcano information.

  17. A long-chain flavodoxin protects Pseudomonas aeruginosa from oxidative stress and host bacterial clearance.

    PubMed

    Moyano, Alejandro J; Tobares, Romina A; Rizzi, Yanina S; Krapp, Adriana R; Mondotte, Juan A; Bocco, José L; Saleh, Maria-Carla; Carrillo, Néstor; Smania, Andrea M

    2014-02-01

    Long-chain flavodoxins, ubiquitous electron shuttles containing flavin mononucleotide (FMN) as prosthetic group, play an important protective role against reactive oxygen species (ROS) in various microorganisms. Pseudomonas aeruginosa is an opportunistic pathogen which frequently has to face ROS toxicity in the environment as well as within the host. We identified a single ORF, hereafter referred to as fldP (for fl avo d oxin from P . aeruginosa), displaying the highest similarity in length, sequence identity and predicted secondary structure with typical long-chain flavodoxins. The gene was cloned and expressed in Escherichia coli. The recombinant product (FldP) could bind FMN and exhibited flavodoxin activity in vitro. Expression of fldP in P. aeruginosa was induced by oxidative stress conditions through an OxyR-independent mechanism, and an fldP-null mutant accumulated higher intracellular ROS levels and exhibited decreased tolerance to H2O2 toxicity compared to wild-type siblings. The mutant phenotype could be complemented by expression of a cyanobacterial flavodoxin. Overexpression of FldP in a mutT-deficient P. aeruginosa strain decreased H2O2-induced cell death and the hypermutability caused by DNA oxidative damage. FldP contributed to the survival of P. aeruginosa within cultured mammalian macrophages and in infected Drosophila melanogaster, which led in turn to accelerated death of the flies. Interestingly, the fldP gene is present in some but not all P. aeruginosa strains, constituting a component of the P. aeruginosa accessory genome. It is located in a genomic island as part of a self-regulated polycistronic operon containing a suite of stress-associated genes. The collected results indicate that the fldP gene encodes a long-chain flavodoxin, which protects the cell from oxidative stress, thereby expanding the capabilities of P. aeruginosa to thrive in hostile environments. PMID:24550745

  18. Autophagy as a Survival Mechanism for Squamous Cell Carcinoma Cells in Endonuclease G-Mediated Apoptosis

    PubMed Central

    Masui, Atsushi; Hamada, Masakazu; Kameyama, Hiroyasu; Wakabayashi, Ken; Takasu, Ayako; Imai, Tomoaki; Iwai, Soichi; Yura, Yoshiaki

    2016-01-01

    Safingol, L- threo-dihydrosphingosine, induces cell death in human oral squamous cell carcinoma (SCC) cells through an endonuclease G (endoG) -mediated pathway. We herein determined whether safingol induced apoptosis and autophagy in oral SCC cells. Safingol induced apoptotic cell death in oral SCC cells in a dose-dependent manner. In safingol-treated cells, microtubule-associated protein 1 light chain 3 (LC3)-I was changed to LC3-II and the cytoplasmic expression of LC3, amount of acidic vesicular organelles (AVOs) stained by acridine orange and autophagic vacuoles were increased, indicating the occurrence of autophagy. An inhibitor of autophagy, 3-methyladenine (3-MA), enhanced the suppressive effects of safingol on cell viability, and this was accompanied by an increase in the number of apoptotic cells and extent of nuclear fragmentation. The nuclear translocation of endoG was minimal at a low concentration of safingol, but markedly increased when combined with 3-MA. The suppressive effects of safingol and 3-MA on cell viability were reduced in endoG siRNA- transfected cells. The scavenging of reactive oxygen species (ROS) prevented cell death induced by the combinational treatment, whereas a pretreatment with a pan-caspase inhibitor z-VAD-fmk did not. These results indicated that safingol induced apoptosis and autophagy in SCC cells and that the suppression of autophagy by 3-MA enhanced apoptosis. Autophagy supports cell survival, but not cell death in the SCC cell system in which apoptosis occurs in an endoG-mediated manner. PMID:27658240

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. Redox cycling of a copper complex with benzaldehyde nitrogen mustard-2-pyridine carboxylic acid hydrazone contributes to its enhanced antitumor activity, but no change in the mechanism of action occurs after chelation.

    PubMed

    Yang, Yinli; Li, Cuiping; Fu, Yun; Liu, Youxun; Zhang, Yu; Zhang, Yanfang; Zhou, Pingxin; Yuan, Yanbin; Zhou, Sufeng; Li, Shaoshan; Li, Changzheng

    2016-03-01

    Many anticancer drugs used in the clinical have potent metal chelating ability. The formed metal complex(es) may exhibit improved (or antagonistic) antitumor activity. However, the underlying mechanism has received limited attention. Therefore, investigation of the mechanism involved in the change upon chelation is required to extend our understanding of the effects of various drugs. In the present study, the proliferation inhibition effect of benzaldehyde nitrogen mustard-2-pyridine carboxylic acid hydrazone (BNMPH) and its copper complex on tumor cell lines was investigated. The copper chelate exhibited almost a 10-fold increase in antitumor activity (with IC50 <5 µM). The results showed that both BNMPH and its copper complex induced reactive oxygen species (ROS) generation, and caused upregulation of caspase 8 and Bax as well as the downregulation of Bcl-2, indicating that apoptosis was involved in the cytotoxic effects. DNA fragmentation noted in the comet assay further supported ROS involvement. The present study indicated that BNMPH and its copper complex effectively induced S phase arrest and the cell cycle arrest was associated with the downregulation of cyclin D1. The formation of acidic vesicular organelles (AVOs) and an increase in cleaved LC3-II demonstrated that autophagy occurred in the HepG2 cells treated with the agents. Taken together, BNMPH and its copper complex exhibited proliferation inhibition via apoptosis, cell cycle arrest and autophagy, which was dependent on ROS. The enhanced antitumor activity of the copper complex was due to its redox-cycling ability, but the mechanism was not altered compared to BNMPH. Our findings may significantly contribute to the understanding of the anti-proliferative effect of BNMPH and its copper complex.

  4. 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.

  5. 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.

  6. 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.

  7. How crucial is back gate misalignment/oversize in double gate MOSFETs for ultra-low-voltage analog/rf applications?

    NASA Astrophysics Data System (ADS)

    Kranti, Abhinav; Armstrong, G. Alastair

    2008-12-01

    In the present work, by investigating the influence of source/drain (S/D) extension region engineering (also known as gate-underlap architecture) in planar Double Gate (DG) SOI MOSFETs, we offer new design insights to achieve high tolerance to gate misalignment/oversize in nanoscale devices for ultra-low-voltage (ULV) analog/rf applications. Our results show that (i) misaligned gate-underlap devices perform significantly better than DG devices with abrupt source/drain junctions with identical misalignment, (ii) misaligned gate underlap performance (with S/D optimization) exceeds perfectly aligned DG devices with abrupt S/D regions and (iii) 25% back gate misalignment can be tolerated without any significant degradation in cut-off frequency ( fT) and intrinsic voltage gain ( AVO). Gate-underlap DG devices designed with spacer-to-straggle ratio lying within the range 2.5 to 3.0 show best tolerance to misaligned/oversize back gate and indeed are better than self-aligned DG MOSFETs with non-underlap (abrupt) S/D regions. Impact of gate length and silicon film thickness scaling is also discussed. These results are very significant as the tolerable limit of misaligned/oversized back gate is considerably extended and the stringent process control requirements to achieve self-alignment can be relaxed for nanoscale planar ULV DG MOSFETs operating in weak-inversion region. The present work provides new opportunities for realizing future ULV analog/rf design with nanoscale gate-underlap DG MOSFETs.

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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

  13. Occurrence and spread of antibiotic resistances in Enterococcus faecium.

    PubMed

    Klare, Ingo; Konstabel, Carola; Badstübner, Dietlinde; Werner, Guido; Witte, Wolfgang

    2003-12-01

    Enterococci are the second to third most important bacterial genus in hospital infections. Especially Enterococcus (E.) faecium possesses a broad spectrum of natural and acquired antibiotic resistances which are presented in detail in this paper. From medical point of view, the transferable resistances to glycopeptides (e.g., vancomycin, VAN, or teicoplanin, TPL) and streptogramins (e.g., quinupristin/dalfopristin, Q/D) in enterococci are of special interest. The VanA type of enterococcal glycopeptide resistance is the most important one (VAN-r, TPL-r); its main reservoir is E. faecium. Glycopeptide-resistant E. faecium (GREF) can be found in hospitals and outside of them, namely in European commercial animal husbandry in which the glycopeptide avoparcin (AVO) was used as growth promoter in the past. There are identical types of the vanA gene clusters in enterococci from different ecological origins (faecal samples of animals, animal feed, patients in hospitals, persons in the community, waste water samples). Obviously, across the food chain (by GREF-contaminated meat products), these multiple-resistant bacteria or their vanA gene clusters can reach humans. In hospital infections, widespread epidemic-virulent E. faecium isolates of the same clone with or without glycopeptide resistance can occur; these strains often harbour different plasmids and the esp gene. This indicates that hospital-adapted epidemic-virulent E. faecium strains have picked up the vanA gene cluster after they were already widely spread. The streptogramin virginiamycin was also used as feed additive in commercial animal husbandry in Europe for more than 20 years, and it created reservoirs for streptogramin-resistant E. faecium (SREF). In 1998/1999, SREF could be isolated in Germany from waste water of sewage treatment plants, from faecal samples and meat products of animals that were fed virginiamycin (cross resistance to Q/D), from stools of humans in the community, and from clinical samples

  14. 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

  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. 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

  17. 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

  18. Integrating SAR with Optical and Thermal Remote Sensing for Operational Near Real-Time Volcano Monitoring

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; Webley, P.; Dehn, J.; Arko, S. A.; McAlpin, D. B.

    2013-12-01

    Volcanic eruptions are among the most significant hazards to human society, capable of triggering natural disasters on regional to global scales. In the last decade, remote sensing techniques have become established in operational forecasting, monitoring, and managing of volcanic hazards. Monitoring organizations, like the Alaska Volcano Observatory (AVO), are nowadays heavily relying on remote sensing data from a variety of optical and thermal sensors to provide time-critical hazard information. Despite the high utilization of these remote sensing data to detect and monitor volcanic eruptions, the presence of clouds and a dependence on solar illumination often limit their impact on decision making processes. Synthetic Aperture Radar (SAR) systems are widely believed to be superior to optical sensors in operational monitoring situations, due to the weather and illumination independence of their observations and the sensitivity of SAR to surface changes and deformation. Despite these benefits, the contributions of SAR to operational volcano monitoring have been limited in the past due to (1) high SAR data costs, (2) traditionally long data processing times, and (3) the low temporal sampling frequencies inherent to most SAR systems. In this study, we present improved data access, data processing, and data integration techniques that mitigate some of the above mentioned limitations and allow, for the first time, a meaningful integration of SAR into operational volcano monitoring systems. We will introduce a new database interface that was developed in cooperation with the Alaska Satellite Facility (ASF) and allows for rapid and seamless data access to all of ASF's SAR data holdings. We will also present processing techniques that improve the temporal frequency with which hazard-related products can be produced. These techniques take advantage of modern signal processing technology as well as new radiometric normalization schemes, both enabling the combination of

  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. 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

  1. (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

  2. Influence of hyperbaric oxygen on left ventricular contractility, total coronary blood flow, and myocardial oxygen consumption in the conscious dog.

    PubMed

    Savitt, M A; Rankin, J S; Elberry, J R; Owen, C H; Camporesi, E M

    1994-06-01

    It is known that hyperbaric oxygenation (HBO) decreases total coronary blood flow (TCBF) and cardiac output (CO). To determine whether this is related to an alteration in myocardial contractility, 10 chronically instrumented conscious dogs were studied during pharmacologic autonomic blockade. Left ventricular (LV) volume was measured with ultrasonic transducers, LV transmural pressure with micromanometers, TCBF with Doppler-flow probes, and coronary AVO2 difference (A-CSO2) was calculated from direct LV and coronary sinus (CS) sampling. To evaluate the effect of increased oxygenation, data were obtained during resting control conditions and during dynamic vena caval occlusions (VCO), at 1 atmosphere of pressure, while breathing air (1 bar/0.21); at 3 atmospheres, breathing compressed air (3 bar/0.21), and at 3 atmospheres breathing 100% oxygen (3 bar/1.0). Because of autonomic blockade, heart rate (HR) was not statistically different in the three conditions. With increasing oxygenation, arterial oxygen tension (PaO2) increased from 85 +/- 5 mmHg (mean +/- SD) at 1 bar/0.21, to 1374 +/- 201 mmHg at 3 bar/1.0 whereas arterial carbon dioxide tension (PaCO2) and pH values were not statistically different. Arterial oxygen content (AO2 content) and CSO2 content increased significantly (both P < 0.05) with increasing PaO2. LV stroke volume (SV), CO, coronary blood flow, and myocardial oxygen consumption (MVO2) were all significantly reduced (P < 0.05) with increasing levels of oxygenation. Intrinsic myocardial function, as measured by the stroke-work/end-diastolic volume relationship was unchanged from 1 bar/0.21 to 3 bar/0.21, and to 3 bar/1.0 (P < 0.20). Thus, the diminished TCBF, CO, and MVO2 associated with HBO do not seem to be associated with a primary alteration in myocardial contractility, but rather may result from a physiologic autoregulation of the myocardium to increasing levels of PaO2. PMID:8061558

  3. 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

  4. 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

  5. Electrogenerated chemiluminescence from heteroleptic iridium(III) complexes with multicolor emission.

    PubMed

    Zhou, Yuyang; Gao, Hongfang; Wang, Xiaomei; Qi, Honglan

    2015-02-16

    Electrogenerated chemiluminescence (ECL) with different emission colors is important in the development of multichannel analytical techniques. In this report, five new heteroleptic iridium(III) complexes were synthesized, and their photophysical, electrochemical, and ECL properties were studied. Here, 2-(2,4-difluorophenyl)pyridine (dfppy, complex 1), 2-phenylbenzo[d]thiazole (bt, complex 2), and 2-phenylpyridine (ppy, complex 3) were used as the main ligands to tune the emission color, while avobenzone (avo) was used as the ancillary ligand. For comparison, complexes 4 and 5 with 2-phenylpyridine and 2-phenylbenzo[d]thiazole as the main ligand, respectively, and acetyl acetone (acac) as the ancillary ligand were also synthesized. All five iridium(III) complexes had strong intraligand absorption bands (π–π*) in the UV region (below 350 nm) and a featureless MLCT (d−π*) transition in the visible 400–500 nm range. Multicolored emissions were observed for these five iridium(III) complexes, including green, orange, and red for complexes 4, 5, 2, 1, 3, respectively. Density functional theory calculations indicate that the electronic density of the highest occupied molecular orbital is entirely located on the C^N ligands and the iridium atom, while the formation of the lowest unoccupied molecular orbital (LUMO) is complicated. The LUMO is mainly assigned to the ancillary ligand for complexes 1 and 3 but to the C^N ligand for complexes 2, 4, and 5. Cyclic voltammetry studies showed that all these complexes have a reversible oxidation wave, but no reduction waves were found in the electrochemical windows of CH2Cl2. The E1/2(ox) values of these complexes ranged from 0.642 to 0.978 V for complexes 3, 4, 2, 5, 1, (in increasing order) and are all lower than that of Ru(bpy)3(2+). Most importantly, when using tripropylamine as a coreactant, complexes 1–5 exhibited intense ECL signals with an emission wavelength centered at 616, 580, 663, 536, and 569 nm, respectively

  6. 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

  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. 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.

  9. 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.

  10. Production-induced changes in reservoir geomechanics

    NASA Astrophysics Data System (ADS)

    Amoyedo, Sunday O.

    sensitivity of the reservoir and overburden shale of Forties Field, I observe that while pore pressure variations have not been significant in most parts of the field, a relatively higher decrease in pore pressure in a region of the reservoir has affected the geomechanical properties of both reservoir and overlying rock strata . I found that strain development in the field accounts, in part, for increased reservoir sand production and a negative velocity change in the overburden, which provides an indication of dilation. I use changes in the AVO intercept and gradient calibrated with laboratory measurements to decouple the time-lapse (4D) difference into saturation and pressure changes. Furthermore, I propose a new modification to time-lapse AVO inversion workflows to account for the effect of porosity change in measurements of time-lapse difference. This is particularly crucial in highly-compacting chalk and poorly consolidated clastic reservoirs. Rock-physics-driven inversion of 3D pre-stack seismic data plays a prominent role in the characterization of both reservoir and overburden rocks. Understanding the rock physics of the overburden rock is required for efficient production of the reservoir and to safeguard wellbore, down-hole assembly and supporting surface facilities. Taking Forties Field as a case study, I observe that while instability and subsequent failure of the overburden in the field can be linked to the rapid decrease of the unconfined compressive strength (UCS) at inclinations close to 45 degrees to the bedding plan, some zones in the overburden are characterized by extreme weakness regardless of the well angle through the rock. I use the correlation between unconfined compressive strength and elastic moduli (Young's and Bulk moduli), coupled with the results of simultaneous inversion to derive 3D elastic moduli, calibrated to laboratory measurements, to characterize the zones of extreme weakness. Time-lapse gravimetry continues to find increasing

  11. 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.

  12. 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

  13. Headless Debris Flows From Mount Spurr Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    McGimsey, R. G.; Neal, C. A.; Waythomas, C. F.; Wessels, R.; Coombs, M. L.; Wallace, K. L.

    2004-12-01

    Sometime between June 20 and July 15, 2004-and contemporaneous with an increase of seismicity beneath the volcano, and elevated gas emissions-a sudden release of impounded water from the summit area of Mt. Spurr volcano produced about a dozen separate debris flow lobes emanating from crevasses and bergschrunds in the surface ice several hundred meters down the east-southeast flank from the summit. These debris flows were first observed by AVO staff on a July 15 overflight and appeared to represent a single flooding event; subsequent snow cover and limited accessibility have prevented direct investigation of these deposits. Observed from the air, they are dark, elongate lobate deposits, up to several hundred meters long and tens of meters wide, draping the steep (up to ~45 degree) slopes and cascading over and into crevasses. A water-rich phase from the flows continued down slope of the termini of several lobate deposits, eroding linear rills into the snow and ice down slope. We infer that the dark material composing these flows is likely remobilized coarse lapilli from the June 1992 tephra fall produced by an eruption of Crater Peak, a satellite vent of Mt. Spurr located 3.5 km to the south. Between 1 and 2 meters of basaltic andesite tephra fell directly on the Spurr summit during the 1992 eruption. The exact mechanism for sudden release of water-laden remobilized tephra flows from the summit basin is not clear. However, observations in early August, 2004, of an 80 m x 110-m-wide pit in the summit area snow and ice suggest the possibility of a partial roof collapse of a summit meltwater basin, likely associated with subglacial melting due to recent heat flux. Such a collapse could have led to the hydraulic surge of meltwater, and rapid mixing with tephra to produce slurries. These slurries traveled down slope beneath the ice surface to emerge through existing crevasses and other easy points of exit on the steep inclines. Mount Spurr is an ice- and snow covered

  14. Volcano-Monitoring Instrumentation in the United States, 2008

    USGS Publications Warehouse

    Guffanti, Marianne; Diefenbach, Angela K.; Ewert, John W.; Ramsey, David W.; Cervelli, Peter F.; Schilling, Steven P.

    2010-01-01

    The United States is one of the most volcanically active countries in the world. According to the global volcanism database of the Smithsonian Institution, the United States (including its Commonwealth of the Northern Mariana Islands) is home to about 170 volcanoes that are in an eruptive phase, have erupted in historical time, or have not erupted recently but are young enough (eruptions within the past 10,000 years) to be capable of reawakening. From 1980 through 2008, 30 of these volcanoes erupted, several repeatedly. Volcano monitoring in the United States is carried out by the U.S. Geological Survey (USGS) Volcano Hazards Program, which operates a system of five volcano observatories-Alaska Volcano Observatory (AVO), Cascades Volcano Observatory (CVO), Hawaiian Volcano Observatory (HVO), Long Valley Observatory (LVO), and Yellowstone Volcano Observatory (YVO). The observatories issue public alerts about conditions and hazards at U.S. volcanoes in support of the USGS mandate under P.L. 93-288 (Stafford Act) to provide timely warnings of potential volcanic disasters to the affected populace and civil authorities. To make efficient use of the Nation's scientific resources, the volcano observatories operate in partnership with universities and other governmental agencies through various formal agreements. The Consortium of U.S. Volcano Observatories (CUSVO) was established in 2001 to promote scientific cooperation among the Federal, academic, and State agencies involved in observatory operations. Other groups also contribute to volcano monitoring by sponsoring long-term installation of geophysical instruments at some volcanoes for specific research projects. This report describes a database of information about permanently installed ground-based instruments used by the U.S. volcano observatories to monitor volcanic activity (unrest and eruptions). The purposes of this Volcano-Monitoring Instrumentation Database (VMID) are to (1) document the Nation's existing

  15. ASTER Urgent Response to the 2006 Eruption of Augustine Volcano, Alaska: Science and Decision Support Gained From Frequent High-resolution, Satellite Thermal Infrared Imaging of Volcanic Events

    NASA Astrophysics Data System (ADS)

    Wessels, R. L.; Ramsey, M. S.; Schneider, D. S.; Coombs, M.; Dehn, J.; Realmuto, V. J.

    2006-12-01

    Augustine Volcano, Alaska explosively erupted on January 11, 2006 after nearly eight months of increasing seismicity, deformation, gas emission, and small phreatic explosions. The volcano produced a total of 13 explosive eruptions during the last three weeks of January 2006. A new summit lava dome and two short, blocky lava flows grew during February and March 2006. A series of 7 daytime and 15 nighttime Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) scenes were acquired in response to this new activity. This response was facilitated by a new ASTER Urgent Request Protocol system. The ASTER data provided several significant observations as a part of a much larger suite of real-time or near-real-time data from other satellite (AVHRR, MODIS), airborne (FLIR, visual, gas), and ground-based (seismometers, radiometers) sensors used at the Alaska Volcano Observatory (AVO). ASTER is well-suited to volcanic observations because of its 15-m to 90-m spatial resolution, its ability to be scheduled and point off-nadir, and its ability to collect visible-near infrared (VNIR) to thermal infrared (TIR) data during both the day and night. Aided by the volcano's high latitude (59.4°N) ASTER was able to provide frequent repeat imaging as short as one day between scenes with an average 6-day repeat during the height of activity. These data provided a time series of high-resolution VNIR, shortwave infrared (SWIR - detects temperatures from about 200°C to > 600°C averaged over a 30-m pixel), and TIR (detects temperatures up to about 100°C averaged over a 90-m pixel) data of the volcano and its eruptive products. Frequent satellite imaging of volcanoes is necessary to record rapid changes in activity and to avoid recurring cloud cover. Of the 22 ASTER scenes acquired between October 30, 2005 and May 30, 2006, the volcano was clear to partly cloudy in 13 scenes. The most useful pre-eruption ASTER Urgent Request image was acquired on December 20. These data

  16. Detecting small geothermal features at Northern Pacific volcanoes with ASTER thermal infrared data

    NASA Astrophysics Data System (ADS)

    Wessels, R.; Senyukov, S.; Tranbenkova, A.; Ramsey, M. S.; Schneider, D. J.

    2004-12-01

    The Alaska Volcano Observatory (AVO) and the Kamchatkan Volcanic Eruption Response Team (KVERT) monitor the eruptive state of volcanoes throughout the Aleutian, Kamchatkan, and Kurile arcs. This is accomplished in part by analyzing thermal infrared (TIR) data from the Advanced Very High Resolution Radiometer (AVHRR) and Moderate-resolution Imaging Spectroradiometer (MODIS) sensors at least twice per day for major thermal anomalies. The AVHRR and MODIS 1-km spatial resolution data have been very useful for detecting large and/or high-temperature thermal signatures such as Strombolian activity as well as lava and pyroclastic flows. Such anomalies commonly indicate a major eruptive event is in progress. However, in order to observe and quantify small and/or lower temperature thermal features such as fumaroles and lava domes, higher spatial resolution data with better radiometric and spectral resolution are required. We have reviewed 2600 available night and day time TIR scenes acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) over the volcanoes of the northern Pacific. The current archive spans from March, 2000 to present. ASTER is the only instrument that routinely acquires high spatial resolution (30 - 90 m) night time data over volcanic targets. These data sets typically contain 5 TIR (8-12 microns) with 90 meter spatial resolution and 6 shortwave infrared (SWIR) bands (1-3 microns) with 30 meter spatial resolution. After the general survey of the volcanic arcs, we have focused our efforts on several targets. Mt. Hague, in the Emmons Lake complex on the Alaska Peninsula, has had mostly cloud-free ASTER observations for twenty night time TIR and six daytime TIR since August 2000. A small lake in the lower crater of Mt. Hague has had a history of appearing and disappearing over the last few years. The ASTER data combined with several recent field observations allow us to track the changes in lake area and associated temperatures

  17. 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

  18. 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).

  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. Seismic Anisotropy of Soft Sands, Offshore Western AUstralia

    NASA Astrophysics Data System (ADS)

    Urosevic, M.; Gurevich, B.

    2007-05-01

    the VSP data. Further analysis of the soft sand anisotropy was conducted on surface seismic data. Magnitude of the overlain shale anisotropy was first established by measurements in the dominant horizontal stress direction. Subsequently pre-stack reflection amplitudes measured along several azimuths were matched to expected amplitudes from anisotropic AVO modelling. The results indicate that the anisotropy of the reservoir sands is high (more than 10%) at sonic frequencies but weak (about 2-3%), at seismic frequencies. We think this anisotropy is caused by the preferential closure of compliant inter-granular contacts oriented perpendicular to the principal horizontal stress. The effect is weaker at seismic frequencies since the wavelength in this case involves shales as well as sand. Furthermore, sonic anisotropy could have also been affected by the local stress conditions around the wellbore.

  1. 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).

  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. Gas hydrate and seismic data analysis by using theoretical approches

    NASA Astrophysics Data System (ADS)

    Tinivella, U.; Accaino, F.; Giustiniani, M.; Loreto, M. F.

    2009-04-01

    -time inversion. Supposing that positive anomalies are due only to the presence of hydrate, the discrepancies between the inverted velocity profile and the velocity for water-filled normally compacted marine sediments are interpreted as due to the presence of gas hydrate (where positive anomalies are present) and free gas (where negative anomalies are present). We can suppose four main relative distribution of free gas: (1) uniform, (2) 50% uniform and 50% random, (3) patchy and (4) random. In the first two cases, the velocity decreases with a small amount of free gas. In the two last cases, instead, the velocity decreases quite linearly versus free gas amount. Finally, the BSR depth obtained by seismic data can be used to estimate the geothemal gradient fitting the seismic depth of the BSR with the theoretical depth evaluated by using modeling. When only seismic data are available, the procedure to estimate gas hydrate and free gas consists essentially in two steps. In the first step, the acoustic velocity field associated to the BSRs is obtained from traveltime tomographic inversion. The second step consists in estimating the concentrations by fitting the theoretical velocities to experimental velocities increasing the amount of gas hydrate and/or free gas; it is obvious that the knowledge of the geological setting is indispensable to suppose the trend of physical properties of sediments versus depth. The theoretical velocities of gas hydrate- and free gas-bearing sediments are obtained using a Biot-type theory described above. A complementary approach is study the AVO effects in multichannel seismic profiles, that can give additional information, such us the Poisson's ratio of sediments, the presence of free gas, the cementation of sediments. Moreover, if avalilable from OBS or OBC, the S-wave velocity is very useful to contrain the estimation and to detect and estimate overpressure condition in the free gas zone. In summary, with the appropriate geological information on the

  4. Effects of peripherally and centrally applied ghrelin in the pathogenesis of ischemia-reperfusion induced injury of the small intestine.

    PubMed

    Pawlik, M W; Obuchowicz, R; Biernat, J; Szczepanski, W; Pajdo, R; Kwiecień, S; Brzozowski, T; Konturek, S J; Pawlik, W W

    2011-08-01

    drugs were used: ghrelin (50 μg/kg i.p. or 1 nmol in 10 μl i.c.v.), 6 hydroxy dopamine (50 mg/kg i.p.), nadolol (0.5 mg/kg i.p.), calcitonin gene related peptide fragment (CGRP(8-37), 100 μg /kg i.p.), capsaicin (5-10 mg/100 ml solution s.c.). The mesenteric blood flow (MBF-ml/min), the intestinal microcirculatory blood flow (LDBF-PU), the arterio-venous oxygen difference (AVO(2)-ml/O(2)/100 ml blood), and the intestinal oxygen uptake (VO(2)) in ml O(2)/min were measured. Mucosal impairment was assessed planimetrically with the use of a digital photo analyzer (LA) and histologically with the use of the six-point Park/Chiu scale. Peripheral administration of ghrelin evoked marked increase of MBF and LDBF by 42% and 48%, respectively, with significant reduction of LA by 38%. When ghrelin was administered at the beginning of the reperfusion period during the short I/R period or prior to the long lasting I/R period, the vascular reactions and protective effects were reduced, but not completely abolished. The central administration of ghrelin before the short I/R period significantly increased the MBF and LDBF by about 32% and 35%, respectively, as well as LA reduction by about 20% in comparison to the control group. However, when ghrelin was administered prior to the long I/R period or after the onset of completed ischemia, neither vascular nor protective effects were noticed. Sensory denervation and the blockade of the CGRP1 receptors totally blocked the protective and hyperemic effects of the peripherally administered ghrelin. Selective blockade of the adrenergic system or blunting of the vagal nerves (vagotomy) significantly but not totally eliminated the effects of centrally applied ghrelin, which were abolished when both adrenergic and parasympathetic pathways were ablated. These results indicate that ghrelin applied centrally or peripherally markedly increases resistance of the intestinal tissue during the I/R period induced mucosal and hyperemic impairment evoked

  5. 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