Parícutin's cyclic activity

Parícutin's volcanic activity during its first year of life included a number of periods characterized by flowing lava. The length of time of individual periods ranged from a few days up to more than a month, and were separated by intervals during which little or no lava flowed at the surface. A cyclic activity is therefore obvious, and a more or less permanent record remains in the form of the lava‐flows. The complete cycle, however, is believed to consist essentially of four stages: (1) Flowing lava; (2) maximum gas activity from the central crater (without flow); (3) the rise of lava in the vent; (4) breaching of the cone in preparation for renewed flow.