Honors Theses and Capstones

Date of Award

Spring 2025

Project Type

Senior Honors Thesis

College or School

CEPS

Department

Earth Sciences

Program or Major

Earth Sciences

Degree Name

Bachelor of Science

First Advisor

J. Matthew Davis

Second Advisor

Sophie Coulson

Third Advisor

Dominick Cirruzi

Abstract

Land subsidence is a frequently overlooked geologic hazard that is caused by natural processes and anthropogenic stressors. The goal of this study is to quantify vertical land motion (VLM) on Long Island, New York and Virginia’s Eastern Shore and evaluate the potential causes of subsidence. The causes considered in this work are glacial isostatic adjustment, groundwater extraction, infrastructure loading, and land cover. This study utilizes interferometric synthetic aperture radar (InSAR) satellite data from Sentinel-1 to calculate linear VLM trends from 2017 to 2023. Datasets for each hypothesis were qualitatively compared to VLM data. Subsidence rates in both regions were found to be anthropogenic and associated with golf courses, cemeteries, farms, and landfills. Long Island and the Eastern Shore have maximum subsidence rates of 19.3 cm/yr and 8.78 cm/yr, respectively, that each occur in landfills. In addition to landfills, subsidence can be caused by soil compaction due to stressors like foot and vehicle traffic, farming processes, and moisture changes in surficial materials. For golf courses, the aeration process is thought to play a role. A relation between wetland, cropland, and urban land cover types and subsidence was found. Additionally, results suggest that groundwater extraction may facilitate subsidence, especially in wetlands on Long Island. Both regions exhibit apparent uplift, which is considered to be an error to some degree due to the use of C-band wavelength, which cannot penetrate dense vegetation. Comparison of results to GPS data and a published VLM dataset suggests that further refinement of InSAR data is necessary to improve confidence in this study’s findings.

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