EAPSI: Understanding the Earth's Crust during the Presence of Large Amounts of Pre-eruptive Magma Conditions at Volcanic Zones

Harmon Lydia J, Nashville TN

Investigators

Abstract

The goal of this project is to understand the Earth's crust at a time when large amounts of magma evolved and became primed for eruption. This project will amalgamate fieldwork, lab work, and computer simulations to study the evolution of the magma bodies that fed the Whakamaru eruptions. The Whakamaru group erupted intensely and explosively; they evacuated hundreds of cubic kilometers of magma in short episodes in the Taupo Volcanic Zone, New Zealand. Large eruptions, like the Whakamaru, provide snapshots of the Earth's crust at times when large amounts of magma are present, and their study yields insights into the ability of the crust to generate eruptible magma. Understanding the development and conditions of pre-eruptive magma bodies is paramount to assess hazards and comprehend the magnitude of potential eruptions. This research will be conducted in collaboration with Darren Gravley at University of Canterbury, New Zealand whose expertise in volcanology and knowledge of the Whakamaru deposits will be instrumental for the work to be developed. The project focuses on quantifying how magma was distributed in the subsurface leading to the Whakamaru eruption sequence. Using erupted natural pumice samples, we can quantify the pre-eruptive magma conditions using crystal-glass thermodynamic equilibrium. Results will make it possible to distinguish particular batches of magma stored at different crustal depths, and also provide insight on the organization and potential interactions between discrete magma bodies. The project also focuses on quantifying the heat flow between the magma body and crust associated with the Whakamaru Group. Phase equilibria modeling will quantify the heat needed within the upper crust to generate and store such quantities of magma, and will assess the conditions of the crust during magma storage. Both conductive and convective heat flow within the crust will be modeled based on the constraints placed by the thermodynamics of crystallizing magma. This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Royal Society of New Zealand.