Comparison of experimental data for reshocked water (points with error bars) with corresponding Hugoniot lines calculated from the analytical fit (solid lines). The principal Hugoniot is shown by the dot-dashed line. Dashed lines show the theoretical regions defined by taking into account 1σ experimental uncertainties for the initial (primary-shock) states. Panels a and b: comparison for the data of Volkov et al. (1980) and of Knudson et al. (2012), respectively.