Présentation au colloque: "EVENEMENTS RAPIDES, INSTABILITES, CHANGEMENTS CULTURELS AU QUATERNAIRE" Aix-en-Provence " Evolution morphologique et culturelle humaine : l'apport des modèles fractals " par

Rapid events, instabilities and cultural changes are numerous during the Quaternary (climates, species evolution, socio-economic systems). Non-linear laws of fractal type are well adapted to their analyze. A log-periodic behavior described by complex fractal dimensions can be applied to inorganic phenomena (earthquakes, stock market crashes), but also to organic phenomena such as biological evolution (chronology of major evolutionary leaps of rodents, dinosaurs, equids, primates, echinoderms). We apply this type of model to the acceleration observed in the economic crisis / no-crisis pattern in Western and pre-Columbian civilizations. The first tests reinforce the universality of the log-periodic model in the description of critical temporal evolutionary phenomena and suggest the existence of vaster underlying laws.