Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 22-25). / Introduction: Centaurs are small bodies whose orbits lie between those of Jupiter and Neptune (Gehrels, 1999). They are thought to be transition objects that originate in the Kuiper belt and occupy the cis-Neptunian region before potentially becoming Jupiter-family or other short-period comets (Dones, Levison, & Duncan, 1996). Their short dynamical lifetimes are on the order of 106 years (Horner, Evans, & Bailey, 2004) due to their unstable, planet-crossing orbits (Horner, Evans, Bailey, & Asher, 2003). Some Centaurs have been observed to be active, and the bodies in the population of active Centaurs have perihelion distances that are statistically smaller than the median perihelion distance for all Centaurs, suggesting that Centaur activity is thermal in nature (Jewitt, 2009). Centaur activity may be observed through changes in the brightness of an object such as those exhibited by the Centaur Chiron (Parker et al., 1997). The presence of a coma around a Centaur may also provide evidence of activity, and dust comae have been detected around several bodies including Chiron (Meech & Belton, 1989; Luu & Jewitt, 1990) and Echeclus (Choi, Weissman, & Polishook, 2006). In addition to comae, other structures have been observed around Centaurs, such as the ring system that was discovered around Chariklo during a stellar occultation (Braga-Ribas et al., 2014). A symmetric feature was observed around Chiron during an occultation (Ruprecht et al., 2015), and some interpret this feature to be possible ring material (Ortiz et al., 2015). Similarly, the trans-Neptunian dwarf planet Haumea was revealed to have a ring during a stellar occultation (Ortiz et al., 2017). The collisional spreading time of Chariklo's rings was calculated to be on the order of 101 years, which is short in comparison to the estimated Centaur lifetime of approximately 106 years (Pan & Wu, 2016), yet Centaur rings are still observed despite this contradiction. Shepherd satellites may serve to increase the lifetime of a Centaur's rings (Pan & Wu, 2016) and maintain distinct ring edges such as those observed in Chariklo's ring system (Charnoz, Canup, Crida, Dones, 2017). Moreover, Centaur activity could supply material to an already present ring system, thus prolonging its lifetime. This study explores the potential connection between Centaur activity and Centaur ring systems by using the N-body integrator REBOUND to model outburst particle interactions and distributions. / by Sophia E. Tigges. / S.B.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1987. / Bibliography: leaves 416-449. / by João Willy Corrêa Rosa. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1997. / Includes bibliographical references (p. 201-204). / by Raymond Paul LeBeau, Jr. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, February 2006. / Includes bibliographical references (p. 189-194). / About 105 bodies larger than 100km in diameter (Jewitt 1998) reside in the Kuiper Belt, beyond the orbit of Neptune. Since 1992 observational surveys have discovered over one thousand of these objects, believed to be fossil remnants of events that occurred nearly 4.5 billion years ago. Sixteen of these objects are currently known to be binaries, and many more are expected to be discovered. As part of the Deep Ecliptic Survey (DES) I have helped catalog nearly one third of the known Kuiper Belt object (KBO) population, and used that database for further physical studies. Recovery observations for dynamical studies of newly discovered objects with the Magellan telescopes and a high resolution imager, MagiC, revealed three binaries, 88611 (2001QT297), 2003QY90, and 2005EO304. One binary was found in the discovery observations, 2003UN284. Lightcurve measurements of these, and other non-binary KBOs, were obtained to look for unique rotational characteristics. Eleven of thirty-three objects, excluding the binaries, were found to have measurable variability. One of these objects, 2002GW32 has a particularly large amplitude (> 1 magnitude) of variability, and 2002GP32 has a relatively short (3.3 hours, single-peaked) lightcurve. / (cont.) Among the binary population all the observed objects showed some level of variation. The secondary of 88611 was fit with a single-peaked period of 5.50*0.02 hours while the primary component appears to be non-variable above the measurement errors (0.05 magnitudes). Neither component appears to be color variable. The components of 2003QY90 are both highly variable yielding single-peaked rotation periods of 3.4±1.1 and 7.1±2.9 hours with amplitudes of 0.34±0.12 and 0.900.36 magnitudes, respectively. The rotation periods are comparable to those of other non-binary KBOs although distinct from that of an identified contact binary. Orbits and partial orbits for Kuiper belt binaries (KBBs) show a wide range of eccentricities, and an increasing number of binaries with decreasing binary semi-major axis. These characteristics exclude the formation models proposed by Funato et al. (2003) and Weidenschilling (2002), respectively. Conversely, the formation models of Astakhov et al. (2005) and Goldreich et al. (2002) appear to describe the observations, at least in part. / by Susan Diane Kern. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1984. / Microfiche copy available in Archives and Science. / Bibliography: leaves 41-43. / by Federico Pardo Casas. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmosphere and Planetary Sciences, 1987. / Includes bibliographies. / by Teresa Christine Solberg. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1984. / Microfiche copy available in Archives and Science. / Bibliography: leaves 40-42. / by Paul S. Cunningham. / M.S.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2011. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 133-137). / High-quality Interferometric Synthetic Aperture Radar (InSAR) surface deformation data for field sites around the world has become widely available over the past decade. Geomechanical models based on InSAR data occur frequently in the literature but few methods of systematically optimizing or comparing them are presented. This work discusses parameterization errors for simplified models of strike-slip, normal, thrust and reservoir-style faulting with the aim of identifying tests or characteristics that can differentiate between error types uniquely. Fault dip errors, slip errors and depth errors are modelled using a simple homogeneous elastic half-space earth model. Simple difference maps prove to be a powerful tool for identifying error types and parameter sensitivity, with gradient maps and gradient difference maps useful for distinguishing between similar cases. The fault dip proves to be more indicative of error resolving capability than the faulting regime; errors on intermediately dipping faults are very difficult to differentiate. More detailed modelling of compound errors, complex geomechanical properties and noisy data is proposed. The use of the tests as the starting point for an artificially intelligent modelling package is briefly discussed. / by Neil Edward James de Laplante. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references. / The objective of this thesis is to improve the microseismic mapping capability for hydrofracture monitoring by using full-waveform information and understand fracturing mechanisms via microsesimic source mechanism inversion. First, we develop an array-based correlation approach to improve the detection of small magnitude events with mechanisms and locations similar to a nearby template event. Second, we extend the correlation detector to the subspace detector by including waveforms from multiple template events. Empirical procedures are presented for building the signal subspace from clusters of events. The distribution of the detection statistics is analyzed to determine subspace detection parameters. The benefits of the subspace detector are demonstrated on a dual-array hydrofracture monitoring dataset. Next, a full-waveform approach is developed for complete moment tensor inversion. By using synthetic data, we show that, for events in the near-field of a single monitoring well, a stable, complete moment tensor can be retrieved by matching the waveforms without additional constraints. At far-field range, we demonstrate that the off-plane moment tensor component is poorly constrained by waveforms recorded at one well. Therefore, additional constraints must be introduced. The complete moment tensor inversion approach is demonstrated with a single well dataset from the Bonner sands hydrofracturing. Moment tensor inversion results show that most events have a dominant double-couple component with the fracture plane orientation close to the average fracture trend derived from the multiple event locations. It suggests that in a reservoir with a high horizontal differential stress like the Bonner sands, the microseismicity occurs predominantly by shearing along natural fractures subparallel to the average fracture trend. Finally, the full-waveform based complete moment tensor inversion method is applied to a dual-array hydrofracture monitoring dataset in Barnett shale at Fort Worth Basin. The determined microseismic source mechanisms reveal both tensile opening on hydraulic fracture strands trending subparallel to the unperturbed maximum horizontal principal stress direction and the reactivation of pre-existing natural fractures along the WNW and N-S directions. Two main contributions are: 1) Improving hydrofracture mapping by developing advanced event detection and relocation algorithms using full waveforms; 2) Understanding the fracturing mechanisms through complete moment tensor inversion and geomechanical analysis. / by Fuxian Song. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1989. / Includes bibliographical references (leaves 248-267). / by Justin Scott Revenaugh. / Ph.D.