Self-organized criticality: Does it have anything to do with criticality and is it useful?

Three aspects of complexity are fractals, chaos, and self-organized critica lity. There are many examples of the applicability of fractals in solid-ear th geophysics, such as earthquakes and landforms. Chaos is widely accepted as being applicable to a variety of geophysical phenomena, for instance, te ctonics and mantle convection. Several simple cellular-automata models have been said to exhibit self-organized criticality. Examples include the sand pile, forest fire and slider-blocks models. It is believed that these are d irectly applicable to landslides, actual forest fires, and earthquakes, res pectively. The slider-block model has been shown to clearly exhibit determi nistic chaos and fractal behaviour. The concept of self-similar cascades ca n explain self-organized critical behaviour. This approach also illustrates the similarities and differences with critical phenomena through associati on with the site-percolation and diffusion-limited aggregation models.