Signatures of land-ocean interactions in coastal morphology

Studying coastal and island evolution in response to environmental drivers offers numerous scientific and societal benefits, as coasts are among the most densely populated regions on Earth. Quantifying surface processes is essential for understanding large-scale landscape development and source-to-sink models, which rely on parameterized representations of environmental factors. Recent studies increasingly integrate empirical datasets into predictive models to better simulate coastal morphodynamics across various spatial and temporal scales. In this thesis, I combine numerical modeling, remote sensing, and data analysis to examine the cross-shore and two-dimensional evolution of the shoreface, coral reefs, and volcanic ocean islands. Chapter 2 applies an energetics model, coupled with a 40-year wave-climate time series, to estimate crossshore sediment transport flux across the shoreface, illustrating how high-energy waves facilitate onshore sediment transport and possibly providing a physical explanation for post-storm beach recovery. Chapter 3 explores the geometric signatures of fluvial erosion within reef morphology in the Society Islands, establishing spatial correlations between major island drainage basins and reef passes, deep channels that dissect the reef flat. Chapter 4 evaluates the relative contributions of surface erosion and geodynamic subsidence to volcanic island morphology through a nondimensional analytical framework and landscape evolution model. Collectively, these chapters identify the geomorphic processes that govern coastal and island evolution by analyzing their morphometric signatures. Through integrated modeling and observation, this thesis establishes quantitative relationships between environmental forces and the modern morphology of nearshore, reef, and volcanic ocean island systems.

Grantor dc:publisher

Massachusetts Institute of Technology and Woods Hole Oceanographic Institution

Year dc:date.issued

2026

Author dc:creator

• Gillen, Megan N.

Advisor dc:contributor.advisor

• Perron, J. Taylor

• Geomorphology
• Ocean islands
• Shoreface

DOI

10.1575/1912/73003

OAI identifier oai:identifier

oai:darchive.mblwhoilibrary.org:1912/73003