Rapid Underway Sediment Classification by Electrical Methods
Abstract
The initial results of a technical feasibility study for using direct current (DC) electric resistivity, electromagnetic (EM), and induced polarization (IP) methods to classify surficial sea-floor sediments are reported herein. Analytical work performed in this study and a review of related work show that both the DC and EM resistivity techniques can provide electrical resistivity measurements of sufficient resolution to classify sediments according to type (mud, clay, silt, sand, gravel, etc.). Both DC and EM antennas must be close to the sea-floor surface (within 10 m) so that surficial sediment resistivities can be sufficiently resolved to permit sediment classification. To resolve the resistivity of a 1-m-thick surficial sea-floor sediment layer, the DC antennas must be deployed less than 1 m above the sea floor. Both DC and EM methods can adequately resolve the resistivity of a 6-m-thick surficial layer at a standoff distance of 10 m. Noise tests with an inverted Schlumberger array towed in the water column and on the sea floor show noise levels to be within acceptable limits. The level of development of the IP method for clay mineral detection is reported; this method shows considerable promise as a contributor to a remote underway sediment classification system. Keywords: Electrical conductivity; Geoacoustics.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1987
- Accession Number
- ADA187447
Entities
People
- Edward C. Mozley
- Philip J. Valent
- Robert F. Corwin
Organizations
- United States Naval Research Laboratory