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Table 1 True, first-guess, and optimized values of frictional parameters in each subregion (Fig. 2a) in the numerical experiments, and the values of cost function calculated by using Eq. (7)

From: Adjoint-based direct data assimilation of GNSS time series for optimizing frictional parameters and predicting postseismic deformation following the 2003 Tokachi-oki earthquake

Region

True values

First-guess values

Optimized values

Exp. 1

Exp. 2

1

 AB (kPa)

8.00

6.00

8.13

6.98

 A (kPa)

60.0

60.0

37.0

50.2

 L (mm)

30.0

50.0

47.3

49.0

2

 AB (kPa)

10.0

8.00

7.18

9.00

 A (kPa)

40.0

40.0

37.3

49.7

 L (mm)

10.0

10.0

9.73

9.03

3

 AB (kPa)

6.00

7.00

7.03

7.95

 A (kPa)

20.0

30.0

28.0

21.0

 L (mm)

20.0

18.0

17.3

17.0

4

 AB (kPa)

6.00

8.00

6.19

8.95

 A (kPa)

20.0

40.0

20.5

30.6

 L (mm)

20.0

20.0

20.3

19.0

5

 AB (kPa)

8.00

6.00

7.61

6.99

 A (kPa)

60.0

60.0

68.8

69.7

 L (mm)

10.0

10.0

9.96

9.04

6

 AB (kPa)

10.0

6.00

8.29

4.99

 A (kPa)

40.0

60.0

63.2

50.0

 L (mm)

10.0

10.0

10.5

11.0

7

 AB (kPa)

10.0

12.0

11.4

11.0

 A (kPa)

40.0

50.0

56.1

60.0

 L (mm)

20.0

17.0

18.3

18.0

8

 AB (kPa)

6.00

8.00

6.77

7.00

 A (kPa)

20.0

20.0

29.5

30.0

 L (mm)

30.0

20.0

21.4

21.0

9

 AB (kPa)

8.00

8.00

11.5

9.00

 A (kPa)

60.0

40.0

33.7

30.0

 L (mm)

10.0

8.00

9.17

9.00

Cost function (assimilation period)

 Exp. 1

0

3.80*101

2.41*10−2

 

 Exp. 2

2.04*103

2.10*103

 

2.03*103

Cost function (prediction period)

 Exp. 1

0

2.82*102

4.58*10−1

 

 Exp. 2

2.95*103

3.20*103

 

3.10*103