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Interpretation of Lunar Topography: Impact Cratering and Surface Roughness

Citation

Rosenburg, Margaret Anne (2014) Interpretation of Lunar Topography: Impact Cratering and Surface Roughness. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/TGC6-8232. http://resolver.caltech.edu/CaltechTHESIS:05282014-080001211

Abstract

This work seeks to understand past and present surface conditions on the Moon using two different but complementary approaches: topographic analysis using high-resolution elevation data from recent spacecraft missions and forward modeling of the dominant agent of lunar surface modification, impact cratering. The first investigation focuses on global surface roughness of the Moon, using a variety of statistical parameters to explore slopes at different scales and their relation to competing geological processes. We find that highlands topography behaves as a nearly self-similar fractal system on scales of order 100 meters, and there is a distinct change in this behavior above and below approximately 1 km. Chapter 2 focuses this analysis on two localized regions: the lunar south pole, including Shackleton crater, and the large mare-filled basins on the nearside of the Moon. In particular, we find that differential slope, a statistical measure of roughness related to the curvature of a topographic profile, is extremely useful in distinguishing between geologic units. Chapter 3 introduces a numerical model that simulates a cratered terrain by emplacing features of characteristic shape geometrically, allowing for tracking of both the topography and surviving rim fragments over time. The power spectral density of cratered terrains is estimated numerically from model results and benchmarked against a 1-dimensional analytic model. The power spectral slope is observed to vary predictably with the size-frequency distribution of craters, as well as the crater shape. The final chapter employs the rim-tracking feature of the cratered terrain model to analyze the evolving size-frequency distribution of craters under different criteria for identifying "visible" craters from surviving rim fragments. A geometric bias exists that systematically over counts large or small craters, depending on the rim fraction required to count a given feature as either visible or erased.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Moon crater topography surface roughness impact size-frequency power spectral density
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Planetary Science
Minor Option:Geophysics
History and Philosophy of Science
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Aharonson, Oded
Thesis Committee:
  • Stevenson, David John (chair)
  • Ingersoll, Andrew P.
  • Gurnis, Michael C.
  • Aharonson, Oded
Defense Date:23 May 2014
Record Number:CaltechTHESIS:05282014-080001211
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:05282014-080001211
DOI:10.7907/TGC6-8232
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8408
Collection:CaltechTHESIS
Deposited By: Margaret Rosenburg
Deposited On:29 May 2014 22:02
Last Modified:11 Apr 2019 17:49

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PDF (Full Thesis)
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PDF (Frontmatter) - Final Version
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PDF (Ch1: Introduction) - Final Version
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PDF (Ch2: Global Surface Roughness) - Final Version
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PDF (Ch3: Differential Slope Applications) - Final Version
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PDF (Ch4: Power Spectral Density) - Final Version
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PDF (Ch5: Geometric Bias) - Final Version
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