We are pleased to welcome Gregor Weber for a HotStuff seminar on: Large magnitude eruptions: Petrological insights into long- and short-term forecasting.

Abstract:

Large-scale volcanic eruptions, characterized by the explosive release of hundreds to several thousand cubic kilometres of magma into the atmosphere, present a significant geological hazard. However, despite the existence of over 1400 potentially active volcanoes worldwide, accurately identifying the systems capable of producing catastrophic events in the future remains a major challenge in long-term eruption forecasting. While volcanic unrest may accompany the lead-up to large explosive eruptions in the short-term, our understanding of the mechanisms and timeframes involved in the accumulation of vast amounts of eruptible magma in the Earth's crust is still limited. Nevertheless, this knowledge is essential for assessing our ability to monitor and predict the development of large explosive eruptions using geophysical techniques.

In this presentation, Gregor will provide a summary of recent studies on the long- and short-term forecasting of caldera-forming eruptions. By analysing extensive geochemical datasets and employing thermo-petrological modelling, Gregor will demonstrate how the diversity of volcanic rocks is linked to the size of the underlying magmatic system. Furthermore, there will be discussion on how this correlation can be utilized to identify volcanoes that have an increased likelihood of producing significant eruptions in the future.

The second part of the talk will focus on elucidating the processes and timing involved in the generation of eruptible magma, drawing on the study of three ignimbrite-forming eruptions. By examining the Sr-isotopes found in plagioclase crystals, we have uncovered evidence that suggests eruptible magmas are formed through a low-temperature melt amalgamation process. This process operates over timescales ranging from decades to centuries. These findings have important implications for our ability to detect and anticipate large-scale volcanic eruptions in the future.