Abstract:
This thesis describes the Magnetotelluric survey undertaken on Mount
Ruapehu in 2005. The aim of the survey was to extend the geographical coverage
to the southwest of the mountain, to confirm the integrity of previous MT
measurements, and to investigate the resistivity structure of Mount Ruapehu
through the use of 3-D modelling.
The structural background to the area is described along with a review of
previous surveys performed around Mount Ruapehu. These surveys are
compared with more general geophysical evidence regarding the underlying
structure of the Taupo Volcanic Zone to derive evidence for specific structural
features beneath Mount Ruapehu.
The theory underlying the magnetotelluric method and its relevance to the
current work is briefly described. The document then goes on to describe the
current magnetotelluric survey, including the measurement process, the data
processing undertaken, the consequent 1-D modelling of the data and its
structural interpretation.
The concept of 3-D modelling, plus the assumptions and simplifications
introduced is outlined, along with the initial attempts at establishing an early
model. The model development lifecycle is then described, which includes both
shallow structure stabilisation within the model and attempts to fit longer period
data to the model.
