ROTTnROCK: a new ERC project to investigate the influence of hydrothermal alteration on volcano instability, eruption triggers and fault reactivation

Hydrothermal alteration gradually and imperceptibly changes the chemical and physical state of the rocks inside a volcano, creating a soft and unstable (or 'rotten') interior. However, the link between 'soft' volcanoes and unpredictable volcanic events remains poorly resolved. ROTTnROCK is a 6-year ERC project, running from 2024-2030, funded through the European Research Council's Synergy Call. The growing ROTTnROCK team will investigate the role of hydrothermal alteration in unpredictable volcanic hazards, such as volcanic instability, alteration-induced eruption triggering, and caldera fault (re-)activation. Specifically, we will use remote sensing and geophysics to identify where and at what scales alteration is occurring. Laboratory investigations will study the chemical fingerprint of alteration and its effects on rock mechanical properties and strength. These approaches will be coupled with 4D volcano stability simulations to produce an innovative and optimised hazard assessment workflow. We will work at selected target sites that show evidence of strong hydrothermal alteration, either associated with flank collapse, collapsing lava domes, crater lakes, or active collapse calderas. This project will transform our understanding of hydrothermal alteration and its impact on volcanic hazards, and will pave the way for strategies to predict and mitigate unexpected volcanic events caused by hydrothermal alteration.