Magnetotelluric survey from north to south onshore the Faroe Islands

Abstract

This work is a master thesis in Exploration Geophysics at The Faculty of Science
and Technology at The University of the Faroe Islands. It is based on magne-
totelluric (MT) measurements at 30 locations in a line directed from north to
south onshore the islands of Eysturoy, Streymoy, Sandoy, and Suðuroy on the
Faroe Islands.
The basic concepts of magnetotellurics are described in such a way that sci-
entists without special knowledge in MT can read the thesis.
Stations on Sandoy are so noisy that they are useless. Stations on Suðuroy
are also noisy and affect the apparent resistivity, though the phase is usable, and
a trustworthy image of the subsurface is achieved. To the north, especially on
Streymoy, the data quality is good, and both apparent resistivity and phase are
trustworthy.
Induction arrows from the real part of the tipper function are drawn, they
mostly point away from seawater. A dimensionality analysis shows strong 3D
effects, and no specific direction was found, that could be used for a strike direc-
tion for 2D modelling.
1D and 2D inversion modelling with determinant impedances is performed.
Also the influence of the seawater between and around the Islands on the
inversion is investigated. The investigation shows that it is absolutely necessary
to include the conductivity of seawater in the computation of a subsurface model.

Date of Award	14 May 2010
Original language	English
Supervisor	Laust B Petersen (Supervisor) & Robert James (Jim) Brown (Supervisor)