Since antiquity it is known that the volcanoes present initiating signs that occasionally are clearly perceptible by the population. A correct interpretation of these signals have allowed the evacuation of the city of Akrotiri upon the eruption of the Thera caldera 3500 years ago, as well as Pompeii and Ercolano upon the eruption of the Vesuvius in the year 79. Nevertheless, these signs are not always perceptible or even interpreted the correctly, an this way some volcanic disasters have occurred along the 20th century: Mont Pelee in Martinique in 1912, although there were many evidences, the authorities refused to evacuate and 30000 people died; Nevado de Ruiz in Colombia in 1985, when multiple alerts from Bogota where not understood by the local authorities of Armero and caused the death of 30000 people in that locality; and a bad decision based in a scientific report that assumed the eruption was over, caused 2000 deaths in the eruption of Chinchon in Mexico in 1982. The experienced gained after the eruptions of the Mt. St. Helens (USA, 1980), the disasters of Chinchón and Nevado de Ruiz, the eruptions of Pinatubeo (Filipinas 1991) and Unzen (japan 1991), as well as the scientific advances in crisis management derived from the International Decade for Natural Disaster Reduction, and specially, the European projects on Volcanic risk, have allowed to establish a clear structure of management that begins by totally separating the technical and scientific aspects from the political.