EAPSI: Investigating Hydrothermal Structures by Electrical Self-potential Measurements

Sealing Christine R, Philadelphia PA

Investigators

Abstract

Understanding the architecture of the hydrothermal system will improve interpretation of geophysical and geochemical signals, enabling a deeper understanding of volcanic processes for more effective monitoring and eruption forecasting. The results of this project have the potential to benefit monitoring and hazard mitigation efforts at active volcanoes in the United States and worldwide. In this project, the researchers will map the structure of the hydrothermal system on White Island volcano, New Zealand. The work will be carried out under the guidance of Dr. Bruce Christenson, Senior Volcanic Fluids Geochemist at GNS Science, New Zealand. The chemistry of gases and thermal waters near the surface provides vital information about the state of the volcano and the magma below. However, these hydrothermal systems present specific challenges for volcanology, as surface waters can alter and dilute volcanic fluids and mask seismic signals that may be coming from the movement of magma at depth. There are also inherent dangers associated with volcano-hydrothermal systems, such as phreatic (steam) and phreatomagmatic (steam + magma) eruptions and contamination of fresh surface waters, all of which put local populations at risk. Understanding the structure and behaviour of these systems is critical for interpreting volcanic signals. This in turn enables better eruption forecasting to protect the lives of people living near active volcanoes. This award will support fieldwork to map the hydrothermal system on White Island, the most active volcano in New Zealand, using a method known as electrical self-potential. As thermal fluids flow through the ground, they generate minute electrical currents. By measuring the change in electrical potential along the ground, these currents can be used to effectively map the path and direction of fluid flow. 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.