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Mapping Coastal Aquifers by Joint Inversion of DC and TEM Soundings‐Three Case Histories
Author(s) -
Albouy Yves,
Andrieux Pierre,
Rakotondrasoa Gérard,
Ritz Michel,
Descloitres Marc,
Join JeanLambert,
Rasolomanana Eddy
Publication year - 2001
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.2001.tb00354.x
Subject(s) - aquifer , geology , resistive touchscreen , electrical resistivity and conductivity , lithology , inversion (geology) , geophysics , fresh water , groundwater , soil science , petrology , geomorphology , geotechnical engineering , structural basin , electrical engineering , engineering
Abstract Electrical and electromagnetic methods are well suited for coastal aquifer studies because of the large contrast in resistivity between fresh water‐bearing and salt water‐bearing formations. Interpretation models for these aquifers typically contain four layers: a highly resistive unsaturated zone; a surficial fresh water aquifer of intermediate resistivity; an underlying conductive, salt water saturated aquifer; and resistive substratum. Additional layers may be added to allow for variations in lithology within the fresh water and salt water layers. Two methods are evaluated: direct current resistivity and time domain electromagnetic soundings. Use of each method alone produces nonunique solutions for resistivities and/or thicknesses of the different layers. We show that joint inversion of vertical electric and time domain electromagnetic soundings produces a more tightly constrained interpretation model at three test sites than is produced by inversion methods applied to each data set independently.