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Earth, Atmospheric, and Planetary Sciences - Master's degree

Mostrando recursos 1 - 20 de 850

  1. The trend of wind speed over the United States during 1998 - 2011

    Feng, Tao, S.M. Massachusetts Institute of Technology
    Through the analysis of the high-resolution radiosonde measurements over the U.S., we identified a decreasing trend near the surface and an increasing trend at the upper levels, which is consistent with previous studies. The decreasing trend of near-surface wind speed is statistically significant (p<0.01). However, the statistical significance of the decreasing trend drops with increases in altitude. We identified a largest negative trend in wind speed close to the surface. The magnitude of this largest negative trend is up to 15 times of the values reported in the previous studies. This might be due to the higher resolution in the...

  2. Poroelastic modeling of groundwater and hydrocarbon reservoirs : investigating the effects of fluid extraction on fault stability

    Rogers, Anna Louise
    The possibility of human-triggered earthquakes is critical to understand for hazard mitigation. This project was developed to better understand the stability of faults in areas with high amounts of fluid extraction, and was applied to both a groundwater and hydrocarbon basin. The theory of poroelasticity was used to calculate the stress changes resulting from fluid flow. Then, the resulting fault stability was evaluated with the the Coulomb Failure Function ([Delta]CFF). A COMSOL and MATLAB workflow was used to derive the results. Two applications were completed. The primary research focused on the extraction from a groundwater aquifer in Lorca, Spain, in...

  3. The effects of fluid pressure changes on fractured rock elastic moduli and surface deformation

    Potter, Jamie, S.M. Massachusetts Institute of Technology
    Reservoir models use the elastic moduli of rock, both bulk and shear, to compute deformation. These moduli may change with pressure and fracture density, but this effect is usually left out of models. This work shows effective elastic moduli of fluid-filled fractured rock through a self consistent method. The calculated effective elastic moduli for a penny-shaped crack are compared to literature values. Effective moduli values for rocks containing rough fractures with asperities are presented. The bulk and shear moduli increase with external stress. Increases in pore pressure cause an increase in bulk modulus but a decrease in shear modulus. The...

  4. Detection and identification of converted modes and source independent converted phase imaging : Groningen, The Netherlands

    AlJishi, Ali Fuad
    Passive seismic monitoring waveform data collected at the Groningen gas field contain many interesting events besides direct P- and S-arrivals. We begin by summarizing the station distribution at Groningen over time and discuss the earthquake catalog. We examine the converted arrivals in order to understand their nature. A combination of move-out analysis, raytracing and finite-difference simulations has revealed that the data contain converted phases from two shallow interfaces. We discuss the possibility of using the Source Independent Converted Phase Imaging method to image the position in the subsurface where these phases have been generated. We examine the limitations of that...

  5. On relative permeability : a new approach to two-phase fluid flow in porous media

    Albarghouty, Lubna Khalid
    Being valid for single-phase flow, Darcy's law is adapted to two-phase flow through the standard approach of relative permeability, in which permeability, rather than being a unique property of the porous medium, becomes a joint property of the porous medium and each fluid phase. The goal of this study is to find a proper, alternate approach to relative permeability that can describe two-phase flow in porous media while maintaining sound physical concepts, specifically that of a unique permeability exclusive to the porous medium. The suggested approach uses the concept of an average viscosity of the two-phase fluid mixture. Viscosity, the...

  6. On the relationship between compressional wave velocity of saturated porous rocks and density : theory and application

    AL Ismail, Marwah I
    Understanding the velocity of the compressional waves travelling through rocks is essential for the purposes of applied geophysics in such areas as groundwater and hydrocarbon exploration. The wave velocity is defined theoretically by the Newton-Laplace equation, which relates the wave velocity, V, to the square root of the ratio of the rock's elastic modulus, M, and its density, [rho] (Bourvie et al., 1987). Therefore, the equation indicates that the velocity is inversely proportional to density. However, the in-situ field measurements and laboratory experiments of compressional wave velocity through different rocks show otherwise. In other words, the velocity is directly proportional...

  7. Cryogenic deformation of two comet and asteroid analogs under varying conditions of saturation

    Atkinson, Jared William Graham
    Sample retrieval from extraterrestrial bodies and in situ resource utilization (ISRU) activities have been identified as some of the most important scientific endeavors of the coming decade. With the failure of Rosetta's Philae lander to penetrate the surface of comet 67P and obtain a sample due to the high compressive strength of the surface, it is becoming obvious that knowledge of the mechanical properties of materials that might be encountered in such environments and under such conditions is critical to future mission success. Two comet/asteroid analogs (Indiana limestone and Bishop tuff), selected based on their contrasting mechanical properties and porosities,...

  8. Cryogenic deformation of two comet and asteroid analogs under varying conditions of saturation

    Atkinson, Jared William Graham
    Sample retrieval from extraterrestrial bodies and in situ resource utilization (ISRU) activities have been identified as some of the most important scientific endeavors of the coming decade. With the failure of Rosetta's Philae lander to penetrate the surface of comet 67P and obtain a sample due to the high compressive strength of the surface, it is becoming obvious that knowledge of the mechanical properties of materials that might be encountered in such environments and under such conditions is critical to future mission success. Two comet/asteroid analogs (Indiana limestone and Bishop tuff), selected based on their contrasting mechanical properties and porosities,...

  9. A comparison of electric and hydraulic approaches to fluid flow simulation and hydraulic parameters inversion

    Al Nasser, Saleh Mohammed
    History matching and prediction of future performance of hydrocarbon reservoirs and groundwater aquifers are considered some of the biggest challenges facing hydrologists and petroleum engineers. The complexity of the simulation method, in addition to the huge amount of input data, makes evaluating the reservoir performance expensive. The conventional reservoir history matching procedure usually requires a trial and error process of altering various reservoir parameters and simulating the pressure distribution and field production, or what is known as 'Forward Modeling'. In this study, I propose the use of regular electrical arrays to simulate aquifer drawdowns. By representing reservoir hydraulic conductivities as...

  10. A comparison of electric and hydraulic approaches to fluid flow simulation and hydraulic parameters inversion

    Al Nasser, Saleh Mohammed
    History matching and prediction of future performance of hydrocarbon reservoirs and groundwater aquifers are considered some of the biggest challenges facing hydrologists and petroleum engineers. The complexity of the simulation method, in addition to the huge amount of input data, makes evaluating the reservoir performance expensive. The conventional reservoir history matching procedure usually requires a trial and error process of altering various reservoir parameters and simulating the pressure distribution and field production, or what is known as 'Forward Modeling'. In this study, I propose the use of regular electrical arrays to simulate aquifer drawdowns. By representing reservoir hydraulic conductivities as...

  11. A preliminary study of industrial meteorology

    Hogan, Marion G
    by Marion G. Hogan.

  12. A preliminary study of industrial meteorology

    Hogan, Marion G
    by Marion G. Hogan.

  13. Investigations of the b-value and its variations on possible earthquake prediction in the North-South China Seismic Belt

    Yu, Diming
    The Gutenberg-Richter b-value is studied extensively by researchers as a possible earthquake precursor. In this thesis, two different approaches to compute the b-value for the purpose of earthquake prediction are investigated and discussed. A new methodology, the b-value ratio method, inspired by a 1988 paper by Morgan et al., is also introduced in this thesis as a variation of b-value. To calculate the b-value ratio, the event catalog has to be separated into a group of larger events and a group of smaller events with a change-point magnitude, which leads to two b-values for the catalog, b-value of the smaller...

  14. Vortices in sinusoidal shear, with applications to Jupiter

    Vilasur Swaminathan, Rohith
    In this thesis, we have studied the existence of vortex steady states in a sinusoidal background shear flow in a 1.75 layer quasi-geostrophic model. Trying to find vortex structures by integrating the Hamiltonian system has the drawback that the vortices lose enstrophy by filamentation and numerical dissipation, while continuing to deform and wobble. Adopting the local optimization technique of Hamiltonian Dirac Simulated Annealing overcomes this drawback and allows us to obtain steady/quasi-steady vortices that have roughly the same area as that of the initial vortex. The steady states that we have generated range from elliptical with major axis aligned with...

  15. Modeling Pluto's light curve in the near infrared : implications for observation post new horizons

    Kosiarek, Molly (Molly R.)
    The effects of volatile transport on Pluto's surface on ground-based observations of Pluto's light curve were studied. Due to Pluto's eccentricity of 0.249, obliquity of 123 degrees, and atmosphere, the transfer of volatiles may cause global surface change over the course of Pluto's orbit. Magellan visible and near infrared data were gathered one month before the New Horizons flyby in order to compare ground-based observing with spacecraft data. Furthermore, a model was created in order to predict how volatile transport will affect ground-based observations in the future. The near-infrared data show large scale surface composition as a function of longitude...

  16. Planetary radar ranging error analysis.

    Coussa, Michael Richard
    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1971.

  17. Formation of authigenic minerals during microbial degradation in artificial marine media

    Joss, Matthew Albert Henry
    I have conducted incubation experiments exploring microbial degradation of organic matter within an artificial sediment designed to simulate an organic-rich siliciclastic marine sediment. Central questions to my research include: 1) How does the presence of dissolved iron influence the degradation and/or protection of organic matter within sediments? 2) How does dissolved iron influence the development of authigenic minerals? 3) How do microbial metabolisms affect dissolved iron concentrations and authigenic mineral precipitation? My experimental system consisted of dead cyanobacterial cells that were mixed with acid-washed glass beads, thereby making an artificial sediment essentially free of contaminants. This material was deposited into...

  18. Hydrographic structure of overflow water passing through the Denmark Strait

    Mastropole, Dana M
    Denmark Strait Overflow Water (DSOW) constitutes the densest portion of North Atlantic Deep Water, which feeds the lower limb of the Atlantic Meridional Overturning Circulation (AMOC). As such, it is critical to understand how DSOW is transferred from the upstream basins in the Nordic Seas, across the Greenland-Scotland Ridge, and to the North Atlantic Ocean. The goal of this study is to characterize the hydrographic structure of the different DSOW constituents at the sill before the water descends into the Irminger Sea using temperature and salinity (T/S) data from 111 shipboard crossings in the vicinity of the sill, collected between...

  19. Effects of lateral heterogeneity on 1D D.C. resistivity and transient electromagnetic soundings in Kuwait

    Nazerali, Nasruddin A
    Aquifer storage and recovery (ASR) of treated wastewater is a viable sustainable water management option for Kuwait. A geophysical survey to characterize the target aquifer in the Dammam Formation was conducted to obtain one-dimensional (1D) resistivity using the D.C. resistivity (DCR) and transient electromagnetic (TEM) methods. For DCR, we implement a systematic approach to obtain a 1 D vertical profile using fixed-thickness and variable-thickness layer inversion techniques in succession. The optimal model has 6 layers above the half-space depth of 101 m, consisting of 3 surface layers down to 15 m depth and 3 intermediate layers, which correspond to the...

  20. Imaging the lowermost mantle (D ") beneath the Pacific Ocean with SKKS coda waves

    Yu, Zhulin
    We apply a generalized Radon transform (GRT) to SKKS data to obtain a large-scale high-resolution image of the lowermost mantle (400 kilometers above the core-mantle boundary) beneath the Pacific Ocean (125° E-75°W, 45° S-65°N in this work). More than 4,000,000 radial teleseismic traces from about 8,000 events (mb >= 5.8) between 1990 and 2015, globally recorded by one or more of a total ~27,000 receivers, were collected from IRIS-DMC. All of the traces were automatically band-pass filtered (10s to 50s), rotated, clustered, deconvoluted, and finally migrated to structural reflectivity profiles using reference wavespeeds according to the iasp91 model. We compare...

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