Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006. / Cataloged from PDF version of thesis. Some pages in the original thesis contain text that runs off the edge of the page. / Includes bibliographical references (pages 36-37). / This project explores whether cloud top altimetry can be used as an accurate and reliable means of estimating the intensity of tropical cyclones. Professor Kerry A. Emanuel developed the theory that is under investigation. His theory aims to calculate the peak surface wind speed in hurricanes using only three parameters, all of which can be collected from satellite imagery: cloud top height, sea surface temperature and cloud top temperature. Cloud top heights for selected hurricanes were obtained from the ICESat, and points were identified where the ICESat may have traversed the hurricanes. These points were compared with IR images to confirm the intersection of the ICESat track and the hurricane tracks. Out of 18 hurricanes examined, four provided feasible points to test this new technique. Two of these points were from hurricanes that were at the end stage of their life cycle; these two data points were discarded. Data from the two usable data points were compared to the recorded wind speeds from Unisys. It seems that the new method is overestimating the maximum surface wind speed by less than 10%. Two data points are insufficient for conclusively validating this technique. However, this project has established a viable method for gathering and analyzing altimetry data, providing a basis for further testing of the theory. / by Valerie Wong. / S.B.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2008. / Includes bibliographical references. / This thesis presents methods of analysis and results from a petroleum reservoir monitoring application using induced seismicity data. The dissertation work is comprised of four major studies, each focusing on a different aspect of induced seismicity. First, methods and issues in location of induced seismicity are discussed, and strategies are proposed for determining accurate hypocenters of induced events. The importance of velocity model and how it impacts the depth determination of reservoir-induced events are demonstrated with real field data. A location method that is better-suited than other existing methods for this application is proposed. The accuracy and efficiency of this proposed location method is demonstrated with field data application.Secondly, event locations and interpretations are presented for about 1300 induced events recorded by a near-surface network over a seven year period at a petroleum field in Oman. The event hypocenters delineate two major northeast-southwest striking faults in the field, which are consistent with fault maps derived from reflection seismic interpretations. Spatiotemporal analysis of induced event locations reveals ongoing large scale fault reactivation in the field, and also suggests compaction of the gas reservoir as the major cause and water injection in the oil reservoir as the secondary cause for inducing seismicity in the field.Thirdly, event locations and interpretations are presented for a different set of induced seismicity data recorded by a deep-borehole network over an 11-month period at the same field. About 5400 events are located and analyzed, and detailed mapping of faults and fractures using the event hypocenters are presented. / (cont.) Patterns of seismicity also reveal faults and fracture systems previously unmapped by reflection seismic. While this dataset allows for much finer interpretation, the results between the two network data are found to be consistent and comparable.Finally, the double-difference relocation and tomography method is applied for event relocation and imaging of the reservoir. Better correlation of relocated events with faults is observed from application of this method to the surface-network events, and detailed velocity and structure images for the reservoir are obtained from application of tomography with the deep network events. / by Sudipta Sarkar. / Ph.D.

Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 21-26). / Compositional analysis of atmospheric and laboratory aerosols is often conducted via single-particle mass spectrometry (SPMS), an in situ and real-time analytical technique that produces mass spectra on a single particle basis. In this study, machine learning classification algorithms are created using a dataset of SPMS spectra to automatically differentiate particles on the basis of chemistry and size. While clustering methods have been used to group aerosols into broad categories based on similarity, these models do not incorporate known aerosols labels and are not explicitly formulated for classification. Furthermore, traditional methods often rely on a smaller set of well-known, important variables whereas the proposed method is more general and flexible, allowing researchers to automatically quantify and select important variables from any aerosol subset. In this work, machine learning algorithms build a predictive model from a training set in which the aerosol type associated with each mass spectrum is known. Several such classification models were created to differentiate aerosol types in four broad categories: fertile soils, mineral/metallic particles, biological, and all other aerosols using -40 common positive and negative spectral features. For this broad categorization, machine learning resulted in a classification accuracy of -93%. More complex models were developed to classify aerosols into specific categories which resulted in a classification accuracy of -87%. The trained model was then applied to a 'blind' mixture of aerosols with model agreement on the presence of secondary organic aerosol, coated and uncoated mineral dust and fertile soil. Additionally, the model is used to characterize an ambient atmospheric dataset collected from the free troposphere. / by Costa Christopoulos. / S.B.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1998. / Includes bibliographical references (p. 76-79). / by Barbara J. Souter. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2009. / Includes bibliographical references. / The primary goal of my doctoral research is to understand the crustal and upper mantle structure and deformation in southeastern Tibet. To improve the resolution in the crust, we developed a new approach for surface-wave array tomography by combining inter-station phase velocity dispersion measurements from empirical Green's functions (EGFs) recovered from ambient noise interferometry and from traditional teleseismic surface-wave two-station (TS) analysis. The non-stationarity (e.g., seasonal changes) and non-uniform distribution of ambient noise sources may obstruct full reconstruction of the surface-wave Green's functions, which may, in turn, degrade the accuracy of the tomographic models. Under the assumption of plane-wave propagation, we developed an iterative method to estimate ambient noise energy distribution, phase velocity bias primarily due to uneven noise energy distribution, and azimuthally anisotropic phase velocity maps. With phase velocity dispersion measurements at periods 10 - 150 s from 1 year data of 75 broad band stations in SE Tibet, we performed inversion for wavespeed variations and azimuthal anisotropy. The tomographic images revealed widespread crustal low-velocity zones (LVZs) at middle/lower crustal depth beneath SE Tibet. There is substantial lateral and vertical variability of these zones and some may be truncated by large faults. / (cont.) The pattern of azimuthal anisotropy in the upper crust is consistent with clockwise rotation around the eastern Himalaya syntaxis and a predominance of simple shear and strike-slip faulting in SE Tibet. Comparison of splitting from SKS observations and from our 3D anisotropic model suggests that the contribution to splitting from the crust is at least as important as from the upper mantle in the region west of Sichuan Basin and north of 26°N. However, beneath Yunnan, splitting signal originates mainly from the upper mantle. The radial changes in deformation pattern argue against vertically coherent lithospheric deformation in Tibet. Combined with the widespread crustal LVZs, this supports models of ductile crustal flow beneath SE Tibet. However, the spatial variation in strength and depth of crustal LVZs and in pattern of azimuthal anisotropy suggests that the 3-D geometry of crustal weak layers is complex and that unhindered crustal flow over large regions may not occur. / by Huajian Yao. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1985. / Microfiche copy available in Archives and Science. / Includes bibliographies. / by Benoit J. Paternoster. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1997. / Includes bibliographical references (leaves 31-36). / by Dana Ruth Stuart. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1996. / Includes bibliographical references (leaves 255-259). / by Huai-Jen Yang. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmosphere and Planetary Sciences, 1988. / Includes bibliographical references. / by Clark Bruce Freise. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1986. / Microfiche copy available in Archives and Science. / Bibliography: leaves 89-90. / by Paul James Hancock. / M.S.