Rainfall-induced Mass Movement as Self-organization Process

Abstract

Self-organizing processes shape Earth's surface, creating complex patterns from simple rules in most landforms. Rainfall-induced mass movements dramatically reshape landscapes through rapid sediment transfer, but whether they self-organize remains unknown. Here we decode their organizational principles by treating spatial changes in scar geometries as fingerprints of the movement process. In 65,936 scars worldwide, we discovered three geometric signals from width, sinuosity and curvature converge on shared patterns and identify a slow-to-fast hierarchy characteristic of self-organizing landforms: long-range correlations show width retaining spatial memory while curvature decorrelates quickly; power spectra quantify a 4-3-2 hierarchy (width-sinuosity-curvature) in scaling exponents; and information flow confirms a top-down organization (width-sinuosity-curvature). Although entropy increases toward finer scales, phase-space reconstructions settle on low-dimensional attractors, revealing hidden order. Together, the evidence shows that width establishes flow corridors through slow dynamics, sinuosity mediates momentum and gravity by intermediate adjustments, and curvature responds rapidly to the terrain. We also developed a model based on simple terrain-inertia trade-offs, demonstrating how mass movements maintain large-scale coherence while flexibly navigating obstacles, potentially extending run-out distances. This organizing rule offers a fundamental mechanism for predicting the destructive reach of mass movements, which are intensifying in our warming, wetter world.