Stability of Euler pole estimates as a function of ISC model exploration. (a) χ² as a function of the imposed σ_m constraints for the dip-slip component with a priori model m₀ = 0, Dc = 30 km and fixed regularization parameters for the strike-slip component. Blue square is the best model for an ISC model with σ_m = 20 mm yr⁻¹. (b) Predicted velocity magnitude at several sites within the North Andean West (NAW) block using Euler pole estimates for ISC models with σ_m values of 8, 20 and 35 mm yr⁻¹. Predicted velocities range from 76.2°W at latitude 2.3°S to 76.6°W at latitude 6°N. (c) Same as (b) but for predicted velocity azimuths.