This project began with the desire to design a house in a town for which I have always had a personal affection: Charleston, South Carolina. The house is designed for a an artist and his family of four and includes a studio for the artist. This design gained its own identity through the research of several historical Charleston housing typologies and acknowledgment of its place in the city. Structure and a panelized system of construction were major factors in the development of the house. As the project progressed, the design of the house moved from a strictly instrumental approach towards a more nuanced design that told a story about how the owners would live in the house. / Master of Architecture

First-hand accounts of sand boils and other liquefaction-related phenomena associated with the Charleston, SC earthquake of 1886 provide clear evidence that liquefaction was common in this event. Recent geologic investigations in the Charleston area have found evidence for the repeated liquefaction of sandy soils in the Charleston area due to recurring large seismic events. Although this information has led to an improved understanding of seismicity in the Charleston region, little hard data exists in terms of ground motion characteristics or levels of seismic loading. A two-year field investigation was undertaken by Virginia Tech to study the liquefaction findings associated with the 1886 event from the perspective of geotechnical engineering. This involved defining the engineering parameters of the Charleston soils on the basis of in-situ and laboratory tests, and estimating the levels of seismic loading required to produce the observed liquefaction phenomena. Of the sites where field tests were performed, the surficial soils were largely formed from ancient beach ridge deposits. The findings showed that soil conditions within these deposits are appropriate for liquefaction. Also, there is clear evidence that soils as old as 230,000 years have liquefied multiple times in the past 10,000 years. Many of these soils remain susceptible to liquefaction at relatively low levels of seismic shaking, although there is some evidence for progressive densification. With respect to the seismic loadings, evidence is presented which suggests that both the magnitude and peak acceleration of the 1886 earthquake were less than what has been proposed by the seismological community (M = 7.7 and 0.5 - 0.6g peak acceleration). The findings of this study indicate that for an M = 7.5 event, peak accelerations in the 0.3 to 0.4g range would serve to explain the observed 1886 liquefaction phenomena. If it is assumed that the magnitude of the 1886 earthquake was less than 7.5, then the estimated peak accelerations increase. / Ph. D.

First-hand reports on the 1886 Charleston earthquake contain numerous accounts for the widespread occurrence of liquefaction related features in and near the meizoseismal zone. Recent geologic studies have found evidence for the repeated liquefaction of sandy soils in the Charleston area due to recurring large seismic events. In the course of this investigation 24 mini-cone penetration tests were performed at seven sites in or near the meizoseismal zone of the 1886 earthquake to determine the factors influencing ground failures due to liquefaction. These tests were supplemented with soil borings, sieve tests and a limited number of standard penetration tests to aid in characterization of the sandy soils. Additionally, soil boring records in Charleston were obtained which provided in-situ testing data in an area with documented historical damage. The range of sites at which testing was done, or information was available, represent locations experiencing various levels of liquefaction and distances from the zone of seismic energy release. Penetration data were used to evaluate resistance of the sandy soil to cyclic loading and fonned the basis for assessing the effects that the lateral extent and distribution of loose sand layers has on the surficial manifestation of liquefaction. With the absence of cementation and extensive soil development, soils as old as late Pleistocene age have been found to be very susceptible to liquefaction. At several sites these soils have undergone at least three episodes of liquefaction and presently exhibit low penetration resistances, indicating that the progressive densification of a liquefiable soil layer can be minor unless it is in very close proximity to a large venting feature. The size and density of occurrence of vents and sand blows has been found to be primarily dependent on the extent of both the liquefiable layer and any overlying resistant layers. Layered system relations utilized with field performance data, and historical and geologic evidence for the occurrence of liquefaction features to suggest that the near surface peak horizontal accelerations induced by the 1886 earthquake were approximately O.3g in the meizoseismal zone and O.2g in the city of Charleston. This is in contrast with previous estimates of seismic shaking all of which point toward values in the range of 0.5 to O.6g. The reason for the different acceleration estimates is not clear at this time, and will be further studied in future extension of this work. / Master of Science

The phenomenon of a single line An architect’s approach to the dissolution of Form and Meaning / Master of Architecture

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Includes bibliographical references. / by Howard Wilson Davis. / M.C.P.

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I am investigating the significance of historic events of flight through image making; particularly incidents that captured the collective imagination and became part of our cultural memory. These events have surpassed mere entries in historical texts and become mythic. In the terms of Jungian psychology, they have become symbolic. In terms of Semiotics, they have become signs. Through photographs and installation, I seek to understand their presence in my, and our, unconscious mind.

The Charleston Uplift (CU), a 30-km-long by 7-km-wide, N46°E-oriented subsurface geologic anomaly in the northern Mississippi embayment near Charleston, Missouri, exhibits up to 36 m of vertical relief across the Paleogene/Quaternary unconformity. Subsurface structural relief, along with the CU’s coincident boundary alignment with contemporary microseismicity and the New Madrid North Fault (NMNF), suggest a structural origin. Subsequent seismic soundings indicate vertical structural relief is present in Cretaceous and Paleozoic horizons, supporting the fault-controlled origin. The southern boundary (CU-s) had not been investigated, nor had any direct fault images been acquired. Integrated microgravity and seismic-reflection methods across the inferred CU-s establish the first image of this fault. Forward modeling indicated that the vertical variation of strata across the CU-s would induce a microgravity anomaly of 1.6 mGal. The observed microgravity anomaly survey across the southern boundary is 1.616 ± .004 mGal, and is consistent with the tectonic interpretation. A subsequently acquired seismic-reflection profile corroborates this interpretation. The imaged fault shows approximately 60, 35, and 35 meters of vertical down-to-the-south throw across the tops of Paleozoic, Cretaceous, and Tertiary horizons, respectively. This confirms the CU is not an erosional feature, but a structurally controlled extension of the NMNF.

Zircon (U-Th)/He (zircon He) dating has become a widely used thermochronologic method in the geosciences. Practitioners have traditionally interpreted (U-Th)/He dates from zircons across a broad spectrum of chemical compositions with a single set of ⁴He diffusion kinetics derived from only a handful of crystals (Reiners et al., 2004). However, it has become increasingly clear that a "one-size-fits-all" approach to these kinetics is inadequate, leading to erroneous conclusions and incongruent data. This dissertation develops a more grain-specific approach by showing the fundamental role that intracrystalline radiation damage plays in determining the He diffusivity in a given zircon. I present three appendices that seek to quantify the radiation damage effect on He diffusion in zircon, explain how this effect manifests in zircon He dates, and show how to exploit such manifestations to better constrain sample thermal histories. Of particular importance, this dissertation represents the first comprehensive study to concentrate on the entire damage spectrum found in natural zircon and also the first to show that two different mechanisms affect He diffusion in zircon in different ways across this spectrum. In the first appendix, I and my fellow co-authors describe results from a series of step-heating experiments that show how the alpha dose of a given zircon, which we interpret to be correlated with accumulated radiation damage, influences its He diffusivity. From 1.2 × 10¹⁶ α/g to 1.4 × 10¹⁸ α/g, He diffusivity at a given temperature decreases by three orders of magnitude, but as alpha dose increases from ~2 × 10¹⁸ α/g to 8.2 × 10¹⁸ α/g, He diffusivity then increases by about nine orders of magnitude. We parameterize both the initial decrease and eventual increase in diffusivity with alpha dose with a function that describes these changes in terms of increasing abundance and size of intracrystalline radiation damage zones and resulting effects on the tortuosity of He migration pathways and dual-domain behavior. This is combined with another equation that describes damage annealing in zircon. The end result is a new model that constrains the coevolution of damage, He diffusivity, and He date in zircon as a function of its actinide content and thermal history. The second and third appendices use this new model to decipher zircon He datasets comprising many single grain dates that are correlated with effective uranium (eU, a proxy for the relative degree of radiation damage among grains from the same sample). The model is critical for proper interpretation of results from igneous settings that show date-eU correlations and were once considered spurious (appendix B). When applied to partially reset sedimentary rocks, other sources of date variability, such as damage and He inheritance, have to be considered as well (appendix C).

Thesis (D. Min.)--Erskine Theological Seminary, 1999. / Abstract. Includes bibliographical references (leaves 123-128).