Contour lines of the (log)normal density function g(ln Dⁱ|ln ${\overline{\mathit{d}}}_{\mathit{n}}^{\mathit{i}}$, ln α, σ), equation (8): median (black solid line) and (black dotted lines) ±2σ, etc. intervals (dotted lines); intensities Dⁱ and ${\overline{\mathit{d}}}_{\mathit{n}}^{\mathit{i}}$ from Table 2 (1957–2015): (a) Alibag (black, ABG) and (b) the four standard Dst observatories (grey, open circles), Hermanus (HER), Kakioka (KAK), Honolulu (HON), San Juan (SJG). Also shown: data from Table 4 (brown, green) for five other superstorms (1903, 1909, 1921, 1940, 1946). In each of (a, b) estimates of Carrington-storm D¹⁸⁵⁹ are shown for Colaba ${\overline{\mathit{d}}}_{\mathbf{CLA}}^{\mathbf{1859}}$ with (blue) and without (orange) the extreme disturbance value at 06:20 UT. 68% (±1σ) credibility intervals in brackets. Bootstrap Kolmogorov-Smirnov probability, KS p.