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Table 3 True, first-guess and optimized values of frictional parameters in each subregion in the numerical experiments in Exps. 1-i, 1-ii, and 1, and values of the 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-i Exp. 1-ii Exp. 1-i Exp. 1-ii Exp. 1
1
 AB (kPa) 8.00 16.0 80.0 19.7 109 8.13
 A (kPa) 60.0 120 600 74.4 233 37.0
 L (mm) 30.0 60.0 300 54.7 281 47.3
2
 AB (kPa) 10.0 20.0 100 20.0 112 7.18
 A (kPa) 40.0 80.0 400 51.6 279 37.3
 L (mm) 10.0 20.0 100 14.9 60.3 9.73
3
 AB (kPa) 6.00 12.0 60.0 15.9 68.8 7.03
 A (kPa) 20.0 40.0 200 16.6 70.8 28.0
 L (mm) 20.0 40.0 200 41.6 224 17.3
4
 AB (kPa) 6.00 12.0 60.0 13.1 63.9 6.19
 A (kPa) 20.0 40.0 200 27.9 108 20.5
 L (mm) 20.0 40.0 200 38.5 219 20.3
5
 AB (kPa) 8.00 16.0 80.0 2.96 142 7.61
 A (kPa) 60.0 120 600 42.5 234 68.8
 L (mm) 10.0 20.0 100 9.42 149 9.96
6
 AB (kPa) 10.0 20.0 100 23.9 117 8.29
 A (kPa) 40.0 80.0 400 25.9 119 63.2
 L (mm) 10.0 20.0 100 18.0 157 10.5
7
 AB (kPa) 10.0 20.0 100 21.9 106 11.4
 A (kPa) 40.0 80.0 400 61.2 422 56.1
 L (mm) 20.0 40.0 200 36.0 149 18.3
8
 AB (kPa) 6.00 12.0 60.0 12.8 68.9 6.77
 A (kPa) 20.0 40.0 200 28.0 71.0 29.5
 L (mm) 30.0 60.0 300 60.6 422 21.4
9
 AB (kPa) 8.00 16.0 80.0 10.8 − 117 11.5
 A (kPa) 60.0 120 600 124 294 33.7
 L (mm) 10.0 20.0 100 11.2 192 9.17
Cost function (assimilation period) 0 1.14*103 2.16*103 2.51*100 6.45*101 2.41*102
Cost function (prediction period) 0 1.33*104 2.08*104 5.01*103 6.55*103 4.58*101