Table 1 Depths (to the top of the layers), thicknesses, conductivities and 95 % confidence intervals of the recovered “joint” 1-D (layered) conductivity model. Note that 1-D model starts from the depth of 1 km; this is because the layered 1-D model is overlain by a thin (of 1 km thickness) shell of laterally variable conductance

10

0.00032

0.00015

0.00069

12

0.00032

0.00016

0.00065

15

0.00034

0.00016

0.00070

15

0.00039

0.00017

0.00091

13

0.00050

0.00018

0.00138

15

0.00073

0.00024

0.00223

15

0.00116

0.00037

0.00370

17

0.00203

0.00068

0.00602

20

0.00374

0.00155

0.00905

23

0.00701

0.00306

0.01606

25

0.01293

0.00511

0.03273

30

0.02182

0.00956

0.04978

35

0.03137

0.01531

0.06429

35

0.04030

0.02118

0.07668

40

0.04775

0.02331

0.09783

40

0.05626

0.02849

0.11108

40

0.06939

0.03300

0.14594

40

0.09014

0.04158

0.19539

50

0.13698

0.06509

0.28830

60

0.25818

0.12804

0.52059

50

0.55871

0.26782

1.16554

60

0.98034

0.56960

1.68726

70

1.13267

0.67351

1.90487

70

1.17502

0.71936

1.91933

80

1.19377

0.74119

1.92270

100

1.21470

0.73511

2.00719

100

1.22527

0.72305

2.07633

110

1.24674

0.71139

2.18497

110

1.30836

0.67681

2.52924

100

1.49968

0.76569

2.93726

100

1.89385

0.86980

4.12354

100

2.46800

1.12520

5.41326

100

3.18402

1.48421

6.83058

100

3.84989

1.80636

8.20526

100

4.19080

1.90199

9.23387

100

4.32177

1.92951

9.68005

100

4.37388

1.91005

10.01588

100

4.38075

1.74362

11.00642

100

4.36998

1.53189

12.46614

100

4.37026

1.41580

13.49000

100

4.38499

1.26547

15.19443

100

4.38851

1.13948

16.90154

100

4.37654

1.04112

18.39754

100

4.37371

0.99958

19.13727

90

4.37127

0.99070

19.28740