Spatial and Temporal Monitoring of Subsurface Saturation and Salinity using Indirect and Non-Intrusive Geophysical Methods

Author: Liam Nell

Field of Study: Science, Technology, Engineering, and/or Math

Program Affiliation: N.A.S.A. Habitable Worlds

Faculty Mentors: Sina Saneiyan

Easel: 86

Timeslot: Morning

Abstract: Detecting subsurface water is crucial for planetary exploration and the search for habitable worlds. Identifying moisture and salinity variations provides insights into past and present habitability and guides future exploration missions. Non-intrusive geophysical techniques, such as Electromagnetic Induction Imaging (EMI) and Electrical Resistivity Tomography (ERT) with Induced Polarization (IP), enable remote assessment of these subsurface conditions. This study examines the sulphur-rich saline Zodletone Spring Site in Oklahoma, a terrestrial analog for extreme planetary environments like Mars. Its dynamic hydrology, unique water chemistry, and microbial interactions resemble extraterrestrial conditions, making it ideal for testing geophysical techniques. Successive EMI and ERT-IP surveys over several months captured temporal variations in subsurface moisture and salinity. Preliminary results indicate seasonal conductivity fluctuations, with EMI efficiently detecting rapid moisture changes and ERT-IP providing deeper structural insights. Findings highlight geophysical techniques' value in planetary exploration, with EMI as the current fastest method for characterizing subsurface conditions.