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Fig. 5 | Swiss Journal of Geosciences

Fig. 5

From: 3D crustal structure of the northwest Alborz region (Iran) from local earthquake tomography

Fig. 5

Illustration of the valuation of appropriate damping. a Trade-off curve between data variance and model variance (Eberhart-Phillips 1986) for a solution after three iterations. The critical damping values are marked by a red polygon. Dash line delineates the estimated observation error level (0.12 s). b Characteristic synthetic data tests (Husen et al. 2000; Kissling 1988). The recovered model in the horizontal plane at 12 km is shown as obtained with different damping values of 70, 150 and 500. Blue and red lines denote positive and negative contrasts of ±5 % relative to the average layer velocity, respectively, and outline the velocity anomalies of the synthetic input model. Grey triangles display stations and black solid lines mark the faults. The arrow illustrates the artifact anomaly generated during the inversion. Areas in white are outside the ray coverage of the data set while areas marked in bold color and enclosed by solid white line are well resolved. In between area in light grey is poorly to fairly-well resolved (see the text for more details about resolution analysis)

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