HIERARCHICAL ORGANIZATION AS A DIAGNOSTIC-APPROACH TO VOLCANO MECHANICS - VALIDATION ON PITON DE LA FOURNAISE

Self-organized systems are often used to describe natural phenomena wh ere power laws and scale invariant geometry are observed. The Piton de la Fournaise volcano shows power-law behavior in many aspects. These include the temporal distribution of eruptions, the frequency-size dis tributions of induced earthquakes, dikes, fissures, lava flows and int erflow periods, all evidence of self-similarity over a finite scale ra nge. We show that the bounds to scale-invariance can be used to derive geomechanical constraints on both the volcano structure and the volca no mechanics. We ascertain that the present magma bodies are multi-len s reservoirs in a quasi-eruptive condition, i.e. a marginally critical state. The scaling organization of dynamic fluid-induced observables on the volcano, such as fluid induced earthquakes, dikes and surface f issures, appears to be controlled by underlying static hierarchical st ructure (geology) similar to that proposed for fluid circulations in h uman physiology. The emergence of saturation lengths for the scalable volcanic observable argues for the finite scalability of complex natur ally self-organized critical systems, including volcano dynamics.