ORCID

0000-0002-4425-434X

Date of Award

5-3-2024

Author's School

Graduate School of Arts and Sciences

Author's Department

Earth & Planetary Sciences

Degree Name

Doctor of Philosophy (PhD)

Degree Type

Dissertation

Abstract

Radar imagery collected by NASA’s Magellan spacecraft enabled the recognition and classification of volcanic features and structures across Venus far beyond the scope of earlier missions. These datasets revealed volcanoes that range in size from <5 km to well over 100 km in diameter. Volcanism is clearly a major, widespread process on Venus, and is a principle expression of the planet’s secular loss of interior heat. For my doctoral work, I utilized ESRI’s ArcMap and ArcGIS Pro to develop a detailed global catalog of volcanoes across Venus to improve our understanding of the morphology, spatial, distribution, and evolution of volcanism on the second planet. Chapter 2 introduces the creation and implementation of my global catalog of volcanoes and volcanic fields on Venus. This new global dataset includes ∼85,000 edifices, ∼99% of which are <5 km in diameter and are geographically widespread across the entire planet. With this catalog, I developed an automated approach to delineating volcanic fields—high spatial concentrations of small volcanoes—and also noted a dearth of volcanoes 20–100 km in diameter, which could be related to the eruption rate and/or availability of the underlying magma supply. Chapter 3 focuses on a unique subset of 162 volcanoes on Venus that appear to have undergone gravitational deformation. These deformed edifices are distributed globally, are situated at a range of elevations, are spatially proximal to a variety of tectonic structures, and are associated with various crustal thickness values, which together suggest that there are numerous drivers of volcano deformation on Venus. Furthermore, I note examples of flank terraces on Tepev Mons, a structural indicator of volcano sagging that has not yet been documented on Venus. Lastly, Chapter 4 employs kernel density estimation as a tool at nine topographic rises, and nine volcanic fields across Venus to delineate regions where future volcano formation could occur, based on the locations of edifices ≤20 km in diameter from our global catalog developed in Chapter 2. These resulting volcano-formation probability maps reveal that the intensity of volcanism producing volcanoes ≤20 km in diameter in the Beta-Atla-Themis (BAT) region, an area well-known for its enhanced volcanism (Airey et al., 2017), is lower than at topographic rises across the rest of the planet. These maps can also be used to identify specific regions across Venus that future missions such as EnVision and VERITAS can image using their higher-resolution radars and thus search for newly formed volcanoes between the time of those missions and when the Venus surface was originally mapped by Magellan. Based on my analysis, I conclude that these missions should target specific regions of high-volcano-spatial density in and around Atla, Imdr, Themis, and Dione Regiones.

Language

English (en)

Chair and Committee

Paul Byrne

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