COMET Webinar: Lorenzo Mantiloni. Insights into dyke pathways and failure of magma-mush reservoirs

Dr. Lorenzo Mantiloni (University of Exeter) presented on Wednesday the 17th of September 2025 about: "Magma finds a way: insights into dyke pathways and failure of magma-mush reservoirs" Talk: 01:45 – 37:20 Questions: 37:20 – 56:19 Abstract: Forecasting volcanic eruptions relies on the knowledge of magma propagation in the Earth’s crust. Modelling magma propagation, in turn, requires addressing two problems: how, where, and when magma breaks out from a reservoir, and what dictates the pathways and speed of magma ascent to the surface. Both problems are challenging but essential to our understanding of volcanic processes, and the key to both is the state of stress underground. Magma propagation through the crust typically occurs by dyking, when no open conduit is available. Models of dyke pathways and velocity, relying on principles of fracture mechanics, have advanced considerably in recent years. The onset of magma propagation in a volcano, on the other hand, is ultimately linked to the instability and failure of a magma reservoir. Models have improved in this regard as well, with increasing interest in magma-mush reservoirs, where magma is stored in a matrix of solid crystals rather than filling a cavity in the crust. Magma-mush reservoirs offer a further challenge, in that failure may occur not only at the reservoir/host rock boundary, but also within the reservoir itself. This presentation will provide some insights into how these problems are being addressed, first introducing some of the recent models of dyke pathways, and then discussing how failure of magma-mush reservoirs can be approached. Finite Element numerical models can be used to explore the state of stress within a mush when accounting for gravity, the stress changes associated to magma supply, and the role of volumetric strain rate in promoting mush failure. As a further step, phase field damage models may be applied to describe dyke nucleation within a mush. Finally, the presentation will discuss ongoing and future applications to real volcanic systems worldwide, such as Sakurajima Volcano in Japan.