P. Schmoldt, PhD - MTNet - DIAS

300
3D-crust profile
The profile 3D-crust uses data from the
same stations as the 3D-mantle profile
(see Figures 8.5 and 8.4 for the location
of profiles and stations), with the difference
being that the data are decomposed
for a geoelectric strike direction
N45W, thus fitting the crustal strike direction.
The inversion adequately reproduces
the crustal structures, but fails
to recover structures at mantle depth
(see Fig. A.8). In particular, the resistivity
of the southern model region
is too high and the location of the interface
cannot be inferred from this inversion
model. However, the RMS misfit
is very low (0.70 with a 5% error floor
for phases and 10% error floor for apparent
resistivities), which may result
in accepting the inversion model without
knowledge of the true subsurface
model. The misfits are insignificant (in
particular, in the presence of noise) and
observable misfits are due to smoothing
constraints working against the recovery
of the sharp contrast at the horizontal
and vertical interfaces, as well
as the issue of small grid size on the
surface.
Profile: 3D-crust
Depth (km)
TE
Log 10(periods)
Log 10(periods)
RMS
TM
-2
-1
0
1
2
3
4
-2
-1
0
1
2
3
4
S N
0
50
100
150
200
250
synL09
synK08
Apparent resistivity
synJ07
synI06
300
0 16 32 48 64 80 96 112 128 144
Distance (km)
(Wm)
50
2000
synL09
synK08
synJ07
synI06
synH05
synG04
synF03
synE02
Misfit
(Total = 0.70)
synH05
synG04
Phase
Log 10(Wm) degrees
Log 10(Wm) degrees
synL09
synK08
synJ07
synI06
synH05
Fig. A.8.: Isotropic 2D inversion results for the ‘3D-crust’ profile on top of the synthetic 3D model (see Figure 8.5 for
profile location). Electric resistivity interfaces at crustal and mantle depths are located between stations synH05 and
synI06. Periods between 10 s and 100 s are related to the crust–mantle boundary; see Section 8.2.1 for a description
of the model. During the inversion the crust is kept fixed at an electric resistivity value of 100 Ωm. The misfit of the
uppermost region originates from the problematic of meeting the cell size requirements for the highest frequencies.
synF03
synG04
synF03
synE02
synE02
A. Appendix