Graduation Year

2021

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Geology

Major Professor

Sarah Kruse, Ph.D.

Committee Member

Charles B Connor, Ph.D.

Committee Member

Jochen Braunmiller, Ph.D.

Committee Member

Brent Garry, Ph.D.

Committee Member

Lieven Verdonck, Ph.D.

Keywords

GPR, 2D Migration, Modeling, Planetary Exploration, Data Library

Abstract

Finding habitable places to keep astronauts safe from surface radiation, magnetic storms, and temperature fluctuations will be an important component of future planetary exploration missions. Remote sensing surveys on other planets indicate the presence of lava tubes. Ground Penetrating Radar (GPR) has shown great potential for detection of tunnels in terrestrial environments. In this research, the capabilities of this near surface rapid exploratory tool for detection of lava tubes are investigated. This dissertation describes terrestrial examples of how GPR can be utilized to explore tubes and addresses the capabilities of GPR for resolving tube-related features such as the floor, fractures, and wall linings. Analysis of data acquired over lava tubes at Lava Beds National Monument (LBNM), CA, USA, and of synthetic models shows that tube ceilings, width and the location of wall linings can be estimated relatively well, while floor recovery requires additional data processing with 2D velocity migration. The synthetic GPR responses to various scenarios were computed with the finite difference time domain (FDTD) GPRMax solver. Models simulate the impact of wall linings, fractures, and a planetary dust mantle on GPR profiles acquired over a lava tube. Ceiling returns appear as high-amplitude returns laterally bounded by zones of diffraction hyperbolas from irregularities in the tube side walls. The ceiling returns precede a period of time characterized by low-amplitude returns. Finally, an online searchable library was designed and developed for storing the acquired LBNM data profiles in both raw and image form. User experience principles were used in the library development provide a simple smooth experience for users (at different expertise levels) of the website. The library also contains metadata, and keyword and map search capabilities.

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