Fig. 6: Comparison of the observed and calculated T_e based on the YSE.

The observed T_e has been derived from 3000 bathymetry and gravity profiles and the calculated T_e has been derived from the brittle¹⁶ and ductile flow^17,18 laws based on a uniform strain rate of 10⁻¹⁴s⁻¹, a thermal age at the time of loading, and a curvature of flexure as shown in 5a, b along the HESC. Dotted black lines show the calculated ‘yield T_e’ based on different brittle and ductile flow parameters. Numbers in bold red font show the original parameters as used in Goetze^17,18 (Supplementary Table S2). Numbers in bold black font identify variations in these parameters. a Calculated T_e based on reducing the coefficient of friction, μ_f,from 0.6^17,18 to 0.3, 0.15 and 0.075. b Calculated T_e based on increasing the value of the pre-exponential constant, A_p, by factors of 1, 10⁴, 10⁸ and 10¹². The factor of 1 corresponds to the original parameters as used in Goetze^17,18. c Calculated T_e based on reducing the activation energies, Q_p and Q_d, from 520 and 535 kJ mol^-117,18 to 450, 350 and 250 kJ mol⁻¹. d Calculated T_e based on reducing the thermal age of the plate at the time of loading by factors of 0%^17,18 to 33%, 66% and 83.5%. e) Bathymetry along the axis of the HESC derived from the SRTM15 V2.4 15 × 15 arc s bathymetric grid⁶⁵.