From micro- to nanoscale crystallization controls on eruptive style in Southern Andean volcanoes

• Applicant: Dr. Pedro Antonio Valdivia Munoz
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 582200136

Explosive volcanic eruptions pose major natural hazards, and understanding the processes that control their intensity is essential for modelling volcanic dynamics and assessing risk. This project will develop a quantitative, multi-scale framework to determine how Fe–Ti oxide crystallization and nanolite formation regulate eruptive style in Southern Andean volcanoes. Using comprehensive natural sample characterization from the Villarrica and Mocho-Choshuenco volcanoes, combined with state-of-the-art imaging and spectroscopic techniques (FE-SEM, Raman spectroscopy, FIB-SEM nanotomography, TEM, and synchrotron micro-CT), I will determine how the distribution of Fe–Ti oxides influences vesicle geometry, connectivity, and permeability. Controlled high-temperature experiments will constrain glass-forming ability, nanolite nucleation thresholds, and the viscosity of their parental melts, resulting in Andean-specific viscosity models that explicitly incorporate nanocrystallization. Complementary indentation and uniaxial compression tests on nanolite-free and nanolite-bearing glasses will quantify how nanoscale heterogeneities influence fracture toughness and failure strength, enabling the exploration of fragmentation processes from a nanoscale perspective. Together, these approaches will establish the mechanistic links between nanoscale crystallization, rheology, and fragmentation, substantially improving our ability to forecast hazardous Andean eruptions and providing new constraints for next-generation numerical models of volcanic dynamics.

• DFG Programme: Fellowship
• International Connection: Chile
• Host: Dr. Loreto Troncoso Aguilera