Extended Data Fig. 2: Terrace-site stratigraphy and luminescence sampling.

a, Map of the Kendeng Hills section of the Solo River from Ngawi to Menden, displaying the location of the six studied sites. Each site has a smaller inset showing the site locations, stratigraphic sections of the strath terraces and sampling locations for luminescence dating. b, Ngandong; the inset for the Ngandong site is shown in more detail to identify the exact location of the sampling site within the context of previous excavations. c, Sembungan excavation I. d, Sembungan excavation II. e, Menden. f, Nglebak. g, Padasmalang. h, Kerek. i, Three-dimensional slice of the Solo River valley, showing the terrace sequences and resulting downcutting rates (derived from 21 terrace samples (n = 21), mean ages with uncertainties presented at 1σ) plotted according to elevation and distance away from the river. The associated downcutting rates have been presented for each terrace, and for the river system as a whole.