P. Schmoldt, PhD - MTNet - DIAS

Modelled Observed
Modelled Observed
10. Data inversion
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Fig. 10.26.: Comparison of observed and modelled response data for the 3D inversion model labelled ‘a’ in Figure 10.27 in terms of
apparent resistivity (ρa) and impedance phase (φ) for all periods and stations. Due to space restrictions station labels are omitted; in
each plot stations are ordered by their latitude from South (left, station pic020) to North (right, station pic001). Individual plots for
each station are given in Section A.4.2.
sistive lithospheric-mantle (Fig. 10.28); however, RMS misfits are in generally higher
than for the previously obtained model with a more conductive lithospheric-mantle (cf.
Fig. 10.29)
To examine feasibility of a more resistive lithospheric-mantle region as well as the possibility
of a highly conductive layer in the uppermost asthenosphere, a series of forward
models are generated. Models are created by using the crustal structure of the minimum
misfit model obtained during the second 3D inversion sequence (labelled ‘a’ in Figure
10.27) and introducing an exponential decrease of electric resistivity with depth in the
lithospheric mantle. The exponential decrease is controlled by the electric resistivity at
the top of the lithospheric-mantle and the depth of the LAB, which is associated with a
resistivity of 100 Ωm (or 10 Ωm in case of a conductive asthenosphere anomaly); sublithospheric
regions are modelled using a 100 Ωm halfspace. In all models an electric
resistivity of 710 Ωm is assigned to the top of the lithospheric-mantle, according to values
obtained for the outer regions of the PICASSO Phase I profile (cf. Fig. 10.27). The LAB
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