Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 61-64). / The author proved that photometry of variable stars can be performed by anyone using the shoestring budget of only a digital camera along with a laptop. Extrinsic variable star Algol was observed using a 14" telescope as well as CCD and had its light curve plotted. In direct comparison, V474 Mon was observed using only a low cost $200 digital camera. Armed with a laptop for data analysis, the author plotted its light curve. Lastly, the whole process of research astronomy was applied to a classroom final project setting. Future work includes expanding this thesis into a full semester long astronomy course for high school students. / by Hollie M. O'Brien. / S.B.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1989. / Includes bibliographical references (leaves 201-219). / by Jeanne Marie Sauber. / Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2000. / Includes bibliographical references (p. 169-179). / Slow earthquakes have been hypothesized to be compound events, i.e. comprised of both an ordinary earthquake and a smooth moment-release transient of longer duration. Low-frequency normal-mode based studies which support the compound event hypothesis have suggested that low-frequency source-spectra of some slow earthquakes require that the slow-component initiated before the fast component. We present observations of low-frequency P-wave energy arriving prior to the high-frequency, mainshock for two oceanic transform fault events. Both the 1994, M, 7.0, Romanche and 1997, M, 6.8, Prince Edward Island events show clear time-domain evidence for episodes of smooth moment release that preferentially radiated energy at low frequencies. Inversions for the moment-rate functions of these events yield compound event sequences where the derivative of the moment-rate function is 2-3 orders of magnitude smaller during the slow event than during the ordinary fast event. The smoothness of the moment-rate function implies that the smooth components of the compound events have rupture and slip velocities which are orders of magnitude smaller than those during ordinary earthquakes. Determining the space-time rupture histories of earthquakes that are only recorded teleseismically is a difficult and non-unique process. We developed a method to determine the 2nd degree polynomial moments of an earthquake's space-time moment release distribution using frequency dependent measurements of global surface- and body-wave arrivals. Our method incorporates both current 3-D earth models and the physical constraint that the source-region have non-negative volume. The 2nd moments provide estimates of the duration, spatial extent, and directivity of an event's rupture. In addition, they can be used to systematically resolve the fault-plane ambiguity. Our values of the 2nd moments for the 1995, Mw 8.0, Jalisco Mexico earthquake agree well with those determined from local slip inversions, and our inversion for the 1st-degree moments of the 1995 Kobe earthquake shows that the measurement errors resulting from unmodeled lateral heterogeneity are small. By estimating the 2nd moments for a catalog of large earthquakes, we are able to systematically resolve the fault-plane ambiguity on a global scale. While the 2nd moments of most large earthquakes are aligned along one of the candidate fault-planes of the event's moment tensor, the 2nd moments of the Romanche and Prince Edwards events are oriented at a high angle to both of their candidate fault-planes. The only type of source-model that can satisfy the observed 0th, 1st, and 2nd degree moments of these events is one that involves slip on two parallel faults. This observation agrees with subevent locations determined using travel-time picks which suggest that multiple parallel faults ruptured in both of these earthquakes. The geometry of both event sequences is consistent with a scenario in which a slow-event on the main transform fault redistributes stress in the region, triggering subevents on both the main and sub-parallel adjacent faults. This evidence for co-seismic rupture of multiple faults combined with other seismic and marine geologic data suggest that deformation at oceanic transforms can be distributed over a wide region (~100 km) on both long (geologic) and short (co-seismic) time-scales. / by Jeffrey Joseph McGuire. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1986. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN. / Includes bibliographies. / by Cynthia Joan Ebinger. / M.S.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2000. / Includes bibliographical references (leaves 50-52). / We investigate the benefits of applying three-dimensional velocity models to seismic event location. We develop a technique for three-dimensional seismic event location, utilizing a finite difference method for travel time calculation and a grid search method for location. We apply this technique to the location of three events in Sichuan Province, China, an area of complex deformation and scattered seismicity. The lateral differences between published event locations and those obtained using this three dimensional technique are between 6.2 and 12.8 km, suggesting that the relocation of a larger number of events may refine our understanding of deformation in this region. The locations using the three-dimensional velocity model compare favorably with locations using a one-dimensional model, returning location depths consistent with the geology of the area and showing smaller location variability when using a jackknifing technique. / by Carolynn E. Vincent. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2008. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Includes bibliographical references. / This dissertation addresses whether simple life forms might have existed on Mars during the late Noachian epoch, and whether those life forms, or their traces, can be detected today. It begins by analyzing the ancient Martian climate in light of new evidence that sulfur chemistry played a prominent role in the planet's early evolution. It finds that sulfur-induced greenhouse warming could have periodically heated the planet enough to support liquid water, thereby creating warm, wet, clement conditions. Moreover, it finds that those warming pulses, while short-lived over geologic time, may have persisted for hundreds of years. If sulfur helped create environmental conditions capable of hosting life, however, it also created conditions that were adverse to sustaining it. In particular, dissipation of sulfur volatiles cooled the climate, and sulfur rainout contributed to the acidity of Martian surface waters. The dissertation therefore proceeds to analyze the potential for persistence and detection of life in terrestrial environments with Mars-like characteristics. It first investigates the potential for detecting ancient life by searching for lipid biomarkers in sulfur-rich acid salt lakes, concluding that a variety of biomarkers may be more resistant to decay than previously believed. It then analyzes soil samples from permafrost, discovering the oldest independently authenticated viable organisms ever found, and positing low-level metabolic activity and DNA repair as a survival mechanism in ancient cells. Finally, the dissertation uses deep sequencing to examine prokaryotic diversity in a terrestrial Mars-like river characterized by low pH and high concentrations of iron and sulfur, with results considered in light of the implications for life detection approaches incorporating new, in situ "PCR in a chip" technology. The dissertation concludes by proposing future work, including the ultimate goal of developing a life detection instrument for Mars. / by Sarah Stewart Johnson. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1985. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN. / Three maps on 3 folded leaves in pocket. / Bibliography: leaves 189-203. / by James Douglas Walker. / Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2004. / Includes bibliographical references (leaves 40-42). / Comets have historically been defined as objects that experience the formation of a "head" (coma) or "tail" as ice and other volatiles that comprise their chemical makeup vaporize when they near the sun. Comets can lose this ability to form a coma or tail, however, through a variety of dynamical processes, creating objects that could chemically be comets but that do not fit the traditional definition. Thus, a new challenge has arisen to correctly define the properties that differentiate comets and asteroids. In this study, a number of cometary candidates were observed in visible and infrared wavelengths in an attempt to correctly classify them as asteroids or dormant or extinct comets. From this data, two groups of objects were identified: one group of possible cometary candidates, and one group of likely outer asteroid belt origin objects. From this and other studies, a broader picture of solar system dynamics can be achieved that will give much insight into not only the current dynamical processes that control interplanetary bodies, but also processes that were important in the formation and stratification of the solar system at its birth. / by Alison J. Klesman. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1997. / Includes bibliographical references (leaves 110-111). / by Yulia V. Garipova. / M.S.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (pages 135-145). / features, with a deep, hot and rapid cyclone situated directly over each pole, and a rapid jet marking the cyclone boundary at 3° from the pole. Extant theories for the zonal jets preclude the possibility of a jet at such high latitudes. This thesis proposes and tests a moist convective hypothesis for polar cyclone formation. Using purely baroclinic forcing, with statistical characteristics motivated by moist convection observed on Jupiter and Saturn, a robust tendency to form a barotropic polar cyclone is identified. A 2 1/2 layer shallow water model is built to test our hypothesis. An 11-dimensional parameter space is explored to determine the most importance controls on cyclone formation. Two sets of experiments are performed: 1) Barotropic and baroclinic 'storms' are briefly forced and then allowed to freely evolve on the polar beta plane, and 2) Forced-dissipative simulations are run, with periodic and randomly placed storms, until statistical equilibrium is reached. Results confirm the well known tendency of positive vorticity anomalies to self-advect poleward if they are intense enough for nonlinear advection to be significant. Likewise, strong negative vorticity anomalies move equatorward. Simulations span several orders of magnitude of energy density, ranging from weak wave-dominated flows to strong cyclones that experience instabilities. We find that a range of behavior, including what is observed on all four giant planets as well as previous simulation studies, can be expressed by varying only 2 nondimensional control parameters: a second baroclinic deformation radius scaled by the planetary radius, LD2=a; and a total energy parameter Êp that scales with the kinetic+potential energy density of the system at statistical equilibrium. In the context of an idealized model, the difference between Jupiter's and Saturn's polar flow regimes may be explained by their different planetary and deformation radii. / by Morgan E. O'Neill. / Ph. D.