Volcanic Eruptions: Cyclicity During Lava Dome Growth

Abstract

We consider the process of slow extrusion of very viscous magma that forms lava domes. Domebuilding eruptions are commonly associated with hazardous phenomena, including pyroclastic flows generated by dome collapses, explosive eruptions and volcanic blasts. These eruptions commonly display fairly regular alternations between periods of high and low or no activity with time scales from hours to years. Usually hazardous phenomena are associated with periods of high magma discharge rate, thus, understanding the causes of pulsatory activity during extrusive eruptions is an important step towards forecasting volcanic behaviour, especially the transition to explosive activity when magma discharge rate increases by a few orders of magnitude. In recent years the risks have increased because the population density in the vicinity of many active volcanoes has increased.