Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1991. / Includes bibliographical references. / by Karen Susan Bartels. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1994. / Includes bibliographical references (p. 146-154). / by Elise Ann Ralph. / Ph.D.

Thesis: S.M., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 101-104). / We developed a (almost) fully automatic earthquake detection and location method to study seismicity on regional scales based on array-processing techniques. We combined the beam-formed network response with template matched-filtering to enhance detection capabilities. We applied our method to the study of the seismicity of the Western Alps, and we claim that it can be applied in many different contexts to quickly get high quality earthquake catalogs. The study of the seismicity of the Western Alps revealed continuous seismic activity, organized into background and strongly clustered seismicity. We detected 9,018 seismic events from August 2012 to August 2013, outperforming the reference catalog that accounts for 1,698 events in the same period. Comparisons between our catalog and reference catalogs/ studies show that we retrieve well the main features of the region. We also studied source parameter differences between background seismicity earthquakes and clustered seismicity earthquakes. Using spectral ratios of collocated events, we measured the seismic moments Mo and corner frequencies f, for earthquakes detected with a subset of 11 template events. We found that background seismicity earthquakes follow the scaling law ... usually associated with self-similar earthquakes, whereas clustered earthquakes strongly deviate from this scaling law. Our observations show that the corner frequencies exhibit little dependency on the seismic moments, following a scaling law around ... We conclude that, in our study region, the degree of clustering seems to be driven by the rupture mechanism. / by Eric Beaucé. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2002. / Includes bibliographical references. / A high resolution stratigraphic study of the Terminal Proterozoic (ca 549 Ma) Hoogland Member of the Kuibis Subgroup, Nama Group, Namibia, revealed the controls on overall carbonate ramp platform morphology in a storm-dominated foreland basin setting. It was found that a generalized suite or class of physical processes that act to restore the seafloor to a relatively flat state by sweeping sediment from the highs and deposit in the lows does not allow for the continued inheritance and propagation of relief between sedimentary "elements" (e.g. laminae, bed, bedset) or larger scale "entities" (e.g. parasequences, systems tracts, depositional sequences). This damping of topographic elements on the seafloor was found to act at a variety of temporal and spatial scales from the sub-annual and sub-meter laminae and facies scale, through the Milankovitch band and meter-scale of parasequences up to the millions of years and scores to hundreds of meters of a depositional sequence. At the meter-scale, bioherms at the base of the studied stratigraphic interval are shown to have been covered and smothered by heterolithic interbeds of shale and fine grained carbonate mud-dominated facies. Facies-scale microbial laminites are shown to posses paleogeographic dip position-dependent centimeter-scale roughness elements that increase in roughness downdip. Relief produced along the tops of laminae is damped out by an overlying sediment rich layer suspended by storms or produced as whitings in the water collumn. Lateral extents of carbonate capped parasequences were found to vary as a function of position within a systems tract or genetic (accomodation) cycle. Late transgressive parasequences are found to be more extensive than those deposited during early transgressive and late highstand conditions due to the presence of basinward thickening shale wedges at their bases. This accommodation space-filling shale acted to decrease the slopes on the platform and allowed the influence of storm wave and current induced seabottom shear stresses to act over a greater area. The presence of a basinward accommodation-filling sediment source evidenced in the basal shale wedges of this foreland basin setting precluded the development of a steep sided rimmed shelf edge. A self-reinforcing ramp profile was maintained despite the fact that thrombolitic and stromatolitic reef forming organisms and processes were present. / by Steven P. DiBenedetto. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1991. / Includes bibliographical references (p. 203-222). / by Kurt Lewis Feigl. / Ph.D.

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 40-46). / The Maria Fold and Thrust Belt (MFTB) and Colorado River Extensional Corridor (CREC) were the sites of atypically extreme compression in Mesozoic time and extension in Cenozoic time, respectively. The orientations of these deformational structures are at odds with the Sevier and Laramide thrust belts and the Basin and Range Extensional Province surrounding these areas, a fact that remains largely unexplained. Data pertaining to metamorphic grade, deformational structures, and plutonism are compiled and reported in order to characterize compression and metamorphism. Field data on the 18.6 Ma Peach Spring Tuff are collected and presented and data on cooling ages are compiled in order to characterize extension. It is suggested that high metamorphic temperatures and ductile compressional structures are related to Late Cretaceous S-type plutonism; furthermore, it is suggested that later extension is related to earlier metamorphism and compression. It is demonstrated that the spread in attitudes of the Peach Spring Tuff correlates well with the degree of post- 18.6 Ma extension. Finally, a favored model is presented for the Mesozoic-Cenozoic evolution of the MFTB and CREC. / by James R. Pershken. / S.B.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1986. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN. / Vita. / Bibliography: leaves 136-143. / by Bruce Douglas Chapman. / Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2010. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 73-76). / Discrepancies in interval velocities estimated from vertical well measurements made with different source central frequencies at Gypsy site could be primarily explained in terms of intrinsic attenuation. Four intervals were chosen for this study based on varying rock properties. The first interval is predominantly shale, second interval is mostly sandstone, and the third interval is made up of shale and sandstone. The fourth interval is the second and third intervals combined. The data used are acquired from three seismic sources; Full Wave Sonic (FWS), Bender log, and Vertical Seismic Profile (VSP) with estimated central frequencies 10kHz, 1kHz, and 100Hz, respectively. The modeling was done using the Discrete Wavenumber (DWN) method and the Logarithmic Dispersion Relation (LDR) to calculate a constant Quality Factor (Q) that best explains the observed velocity dispersion for each of the intervals of interest. The elastic scattering component of the dispersion is negligible. Intrinsic quality factors of 54,35,28, and 30 best explain the field data for first, second, third, and fourth intervals, respectively. The identification and subsequent modeling of velocity dispersion and its components provide key information for integrated reservoir characterization and better enable the prediction of the seismic response at different frequencies. / by Sami Ibrahim Alsaadan. / S.M.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1998. / Includes bibliographical references (leaves 196-210). / by Weiqun Shi. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1988. / Includes bibliographies. / by Michael Roy Nelson. / Ph.D.