Relationships between erosion rates and physiographic factors of drainage basins through a regression analysis: The case of Tahiti Nui Island

Tahiti Nui is a quiescent tropical volcanic island (French Polynesia) characterized by an intense erosion (up to 0.25 km3·kyr−1 over the last 1 Ma) that resulted in 27 main drainage basins radially distributed around central depression. Those are different rates (from 0.07 24.6 10−2 km3·kyr−1), ages 469 892 ka), micro-climate set-ups and other landform factors. In this study, we assess, terms of explicative power, possible links between relevant physiographic factors, through regression analysis obeying parsimony principle. The best models include, decreasing order importance, following factors: size (Planar Area or Maximal River Length) and/or height (Maximal Altitude); planar shape (Shape Factor Relative Width); inclination (Main Longitudinal Slope, Mean Maximum Altitude Depth) mean precipitation (Average Annual Rainfall). Erosion Duration positions along North-South East-West directions, which were used highlight effect winds, did not show significant on rates. all fitting models, greatest weight was associated with revealing highest ones measured largest basins. model based five factors per basin, importance: Planar Area, Width, Altitude, Main Slope Average Rainfall. factor seems be most parameter since it explains itself part Finally, role average annual rainfall consistent models. This suggests more suitable constrain precipitations must considered, probably linked temporal climate variability as well frequency cyclone-driven rainfall. Besides, Rainfall generally positive small synonymous minor role.