The Good Old Days Were Better: Agrarian Collapse and Tectonics

The theory of plate tectonics contends that the continental plates occupied by humanity are in motion. The hypothesis of agrarian collapse (HAC) holds that gradual, as well as seismic, earth movement can induce ground slope change and modify land-to-sea level relationships, thereby altering the distribution of surface and subsurface runoff, which can lead to abandonment of agricultural land. Mechanical principles underlying ongoing abandonment are detailed for large-scale irrigation systems of the Andean Cordillera Negra. These principles are compatible with a historical scenario integrating urban development at pre-Hispaic Chan Chan, capital of the Chimor polity, with expansion, reform, and collapse of the city's agricultural hinterland. The applicability of the mechanics of agrarian collapse to two other centers of past civilization is briefly considered.