No single model for supersized eruptions and their magma bodies

Supereruptions are the endmember of explosive volcanic activity, yet, their magmatic processes and eruption dynamics are debated. This Review synthesizes data from 13 Quaternary supereruptive events with geophysical monitoring of active caldera volcanoes to highlight the diversity in large, modern, silicic magmatic systems. Supereruptions are the largest explosive volcanic eruptions on Earth. They generate catastrophic, widespread ash-fall blankets and voluminous ignimbrites, with accompanying caldera collapse. However, the mechanisms of generation, storage and evacuation of the parental silicic magma bodies remain controversial. In this Review, we synthesize field, laboratory and petrological evidence from 13 Quaternary supereruptions to illustrate the range of diversity in these phenomena. Supereruptions can start mildly over weeks to months before escalating into climactic activity, or go into vigorous activity immediately. Individual supereruptions can occupy periods of days to weeks, or be prolonged over decades. The magmatic sources vary from single bodies of magma to multiple magma bodies that are simultaneously or sequentially tapped. In all 13 cases, the crystal-rich (>50-60% crystals), deep roots (>10 km) of the magmatic systems had lifetimes of tens of thousands to hundreds of thousands of years or more. In contrast, the erupted magmas were assembled at shallower depths (4-10 km) on shorter timescales, sometimes within centuries. Geological knowledge of past events, combined with modern geophysical techniques, demonstrate how large silicic caldera volcanoes (that have had past supereruptions) operate today. Future research is particularly needed to better constrain the processes behind modern volcanic unrest and the signals that might herald an impending volcanic eruption, regardless of size.