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Criticality, Self-Organized

Ecological Statistics

  1. Bai-Lian Li

Published Online: 15 SEP 2006

DOI: 10.1002/9780470057339.vas013

Encyclopedia of Environmetrics

Encyclopedia of Environmetrics

How to Cite

Li, B.-L. 2006. Criticality, Self-Organized. Encyclopedia of Environmetrics. 2.

Author Information

  1. University of New Mexico, NM, USA

Publication History

  1. Published Online: 15 SEP 2006


The causes and possible relations between the abundance of fractal structures (see Fractal dimensions) and 1/f signals found in nature have puzzled scientists for years. Based on observations of computer simulations of the cellular automata sandpile model, the term self-organized criticality (SOC) was invented by theoretical physicists and was used to explain a universal dynamic organizing process governing various fractal growths in space and time. SOC describes that systems organize themselves so their internal dynamics produce critical behavior over a very wide range of length scales. The term consists of two parts. Self-organization has been used to describe the ability of certain nonequilibrium systems to develop structures and patterns often without explicit pressure or involvement from outside the systems. Criticality is a technical word used in connection with phase transitions, and has a very precise meaning, in which the system becomes critical when all members of the system influence each other and events of all sizes occur.