P. Schmoldt, PhD - MTNet - DIAS

10. Data inversion
Short period range (0.001 - 10 s)
Long period range (0.001-100 s)
Model:
Depth (km)
Depth (km)
0
10
20
30
40
50
0
10
20
30
40
50
a3b1t6
1 2
Log 10 resistivity (Wm)
1 2 3
Log 10 resistivity (Wm)
Depth (km)
Depth (km)
0
10
20
30
40
50
0
10
20
30
40
50
a2b1t10
1 2
Log 10 resistivity (Wm)
1 2 3
Log 10 resistivity (Wm)
a5b1t3
1 2
Log 10 resistivity (Wm)
1 2 3
Log 10 resistivity (Wm)
Stations averaged: All (pic001-pic020) DC train line (pic013-pic017) Northernmost (pic001 –pic003)
Fig. 10.3.: Resistivity–depth profiles of horizontally averaged models for different regions of the Tajo Basin subsurface, obtained
through inversion of PICASSO Phase I response data from two different period ranges and three sets of smoothing parameters; see
text for details. Different regions are indicated by colour, with solid and dashes lines denoting average values and variance of electric
resistivity for the different regions, respectively. Variance curves for the northernmost stations (dashed green lines) are covered by
their average value curves due to the small lateral variation of electric resistivity in the respective regions.
lines in Figure 10.2), the distribution of electric resistivity along the profile is also examined.
For that purpose horizontal averages of electric resistivities from two distinct regions
are calculated (red and green lines in Figure 10.3, respectively): structures beneath stations
pic013 – pic017, located in the proximity of the DC train line with response curves
truncated at longer periods (see Section 9.4 for details); and stations pic001 – pic003, located
at the northern end of the profile, thus considerably far away from the DC train
lines. Average resistivity–depth profiles for these two regions are calculated separately
for the different smoothing parameters and period ranges, respective results are compared
with each other and the average resistivity for the whole profile. The resulting Figure
10.3 infers noticeable variations in resistivity along the profile, with a more resistive nature
of the stations close to the train line. The increased resistivity for the region in close
proximity to the train line is likely to originate from data truncation (cf. Sec. 9) and
230
Depth (km)
Depth (km)
0
10
20
30
40
50
0
10
20
30
40
50