LC1DINV : laterally-constrained 1-D inversion for processing airborne EM data

BGS has recently developed jointly with GTK (Geological Survey of Finland) an advanced
airborne geoscience capability and has commenced extended airborne surveying of Northern
Ireland with other areas soon to follow. Large multi-frequency electromagnetic data sets
comprise an important part of these surveys. In order to aid the interpretation of these data
sets, we have developed “LC1DINV”, a laterally constrained one-dimensional inversion
algorithm.
LC1DINV inverts for the resistivities and thicknesses of a few (two or three) horizontal layers
using a regularised conjugate gradient optimisation routine. The inverse problem is stabilised
through the use of lateral constraints that ensure that model parameters change smoothly in
the horizontal direction while preserving our ability to distinguish layer boundaries. Tests on
synthetic models confirm the stability and efficiency of the method.