Eruption patterns of parasitic volcanoes

Abstract

Eruption patterns of parasitic volcanoes are discussed in order to study their correlation to the activities of their parental polygenetic volcanoes. The distribution density of parasitic vents on polygenetic volcanoes is diversified, probably corresponding to the age and structure of parental volcanoes. Describing existing parasitic cones contextually in relation to parental volcanoes is as indispensable as collecting observational data of their actual formations. In the present paper, spatial distributions of parasitic cones are classified tentatively into the following three categories: individually radial, directionally radial and annular determined according to feature’s placement around the central axes of the parental volcanoes. The formations of parasitic vents are discussed from the standpoint of material mechanics. Derived from this approach, the maximum shear stress model suggests the possibility of twin parasites, and their existence on particular volcanoes verifies the possible validity of this interpretation though it may be not necessarily universally applicable to every volcano due to various effects of volcanism and lack of complexity in the model. Some characteristics of parasitic eruptions are discussed, such as monogenetic activity of parasitic vents and simultaneous eruptions of summit craters and parasitic vents. Parasitic volcanism proves to be not merely an auxiliary feature of its parental volcano but closely correlated with magma plumbing systems.