Affordable Access

The competing impacts of geology and groundwater on electrical resistivity around Wrightsville Beach, NC

Authors
Journal
Continental Shelf Research
0278-4343
Publisher
Elsevier
Publication Date
Volume
31
Identifiers
DOI: 10.1016/j.csr.2011.02.008
Keywords
  • Resistivity
  • Groundwater
  • Electromagnetic Techniques
Disciplines
  • Physics

Abstract

Abstract Measurements of electrical resistivity have long been used to find freshwater resources below the earth's surface. Recently, offshore resistivity and electromagnetic techniques have been used to map occurrences of submarine groundwater originating from the offshore extension of terrestrial aquifers. In many cases, observations of a high resistivity (low conductivity) anomaly in the seafloor are sufficient to suggest the presence of fresh (and less conductive) pore waters. Data from offshore Wrightsville Beach, NC show highly variable resistivity structure, with moderately high resistivity at depths of ∼20 m subsurface that is at least in part caused by lithologic complexity in an underlying limestone unit, the Castle Hayne. These offshore results suggest caution in the interpretation of resistivity anomalies simply in terms of groundwater volumes. In contrast, low onshore resistivities show evidence for intrusion of saltwater into the subsurface beneath the beach, adjacent to areas of pumping for water supply.

There are no comments yet on this publication. Be the first to share your thoughts.