Extended Data Fig. 2: Correlations between river profile concavity and tectonic and climatic indices without averaging over basins.

Binned river segment concavity index (NCI) values⁷ are strongly correlated with three indices of tectonic activity: peak ground acceleration from the Global Earthquake Model²⁰ (a), the distance to the nearest plate boundary²⁴ (b), and mean river profile gradient⁷ (slope, c). NCI values are only weakly correlated with three climatic indices: precipitation²² (P, d), potential evapotranspiration²³ (PET, e), and aridity index^7,23 (P/PET, f). Spearman rank correlations (ρ) are shown for the un-binned values. The rank correlations of the plotted (that is, binned) points are visibly stronger, but vary depending on the details of the binning. The data are averaged within 50 bins each containing 2 percent of the data.