Forecasting Colloquium - Stefan Hergarten

30 Years of Self-Organized Criticality -- What Remains?

While the framework of deterministic chaos dominated nonlinear dynamics from the 1960s, the concept of Self-Organized Criticality (SOC) became popular in the late 1980s. Starting from the point that some simple models apparently self-organize to a state with emerging fractal properties, it promised to become a universal concept for explaining both heavy-tailed distributions of events as they occur in several natural phenomena as well as signals that are somewhere between chaotic and predictable behavior. Since then, the phenomenological description of SOC turned out to be useful in several fields and is thus widely referenced in numerous studies. In turn, the concept did not keep to promise of providing a unified theory so far. There even seems to be some stagnation in developing the theoretical concept behind SOC, so that the question arises what remains beyond the keyword and several thousand citations.