Rationale for the Scientific Drilling Project “INTERACTION”: Interactions Between Life, Rifting and Caldera Tectonics in Okataina

Abstract

The Okataina Volcanic Centre (OVC) in Aotearoa, New Zealand is of high cultural significance to M?ori. The OVC is also a nested caldera complex, one of two giant active calderas of the Taup? Volcanic Zone (TVZ), ranked as New Zealand’s highest threat volcano. In-situ, sub-surface observations required to better understand interactions between volcanism, rifting, fluid circulation and the deep biosphere are sparse. We propose the INTERACTION (Interactions between life, rifting and caldera tectonics in Okataina) scientific drilling programme to provide rock and fluid samples, downhole measurements and a base for a long-term observatory. Downhole samples and data, and new high-resolution ground-based surveys near the borehole will refine and fill gaps in the extensive geophysical, geological and geochemical datasets collected across the OVC and wider TVZ region since the 1950s, and advance fundamental concepts of caldera systems globally.
Scientific drilling at the OVC, coupled with extensive stakeholder engagement will lead to improved resilience to natural hazards and sustainable management of groundwater and geothermal resources. Close collaboration with M?ori will achieve both scientific and cultural outcomes. New geothermal concepts (heat source, permeability and recharge), geophysical data acquisition and new technology deployment, will help future geothermal development in the central TVZ and elsewhere. Altogether, scientific drilling at the OVC will advance our understanding of: (1) drivers to volcanic eruptions, feedbacks between volcanic and seismic events, caldera evolution; (2) large-scale hydrology and magmatic systems; and (3) diversity, function, and geological processes that support deep subsurface microbial activity and response to a highly active geosphere. At these early stages of planning, we invite contributions to the concept of this project in the exceptional OVC settings and strengthen linkages with other ongoing research and geothermal drilling programmes.