Dr Judith Stepper

The key question asked of a volcano monitoring agency is “When will the volcano erupt?” While it is possible to determine whether a volcano is in a state of unrest, it is very difficult to forecast an imminent eruption based on geophysical monitoring signals alone. We will use petrography and geochemistry to decipher magmatic processes that are preserved within erupted material, as crystals and volcanic glass or groundmass reflect a history of growth within a variable (pressure, temperature, chemical, etc.) magmatic environment. We have recently demonstrated that these magma-speedometric methods allow the quantification of rates and timing of events leading to former explosive eruptions, as well as informing the geometry of the respective plumbing systems. In this project we will extend these insights to effusive eruptions, providing geophysical monitoring experts with knowledge about how the entire subvolcanic plumbing system operates. We will combine this field-leading knowledge with seismic and ground deformation observations that signal magma movement at depth. Building models will enhance scientific understanding of how seismicity and deformation are modulated by variations in volume, depth, and conduit geometry during magma ascent, and how these signals change over time as magma ascends from great depth to the surface. High-resolution geochemical information gained from deposits of previous eruptions will provide the boundary conditions for these models. Combining the models with future real-life geophysical observations during periods of volcanic unrest will allow rapid interpretation to identify timing, size, and style of potential eruptions. This method will be directly applied to monitoring of New Zealand’s volcanoes and incorporated into the GeoNet project. The outcomes of this work will protect the lives of people and the long-term livelihoods of stakeholders in volcanically active areas.