Volcano Monitoring With Magnetic Measurements: A Simulation of Eruptions at Axial Seamount, Kīlauea, Bárðarbunga, and Mount Saint Helens

• Published in: Geophysical research letters 2022-09, Vol.49 (17), p.n/a
• Main Authors: Biasi, Joseph, Tivey, Maurice, Fluegel, Bailey
• Format: Article
• Language: English
• Subjects: Curie temperature; Data acquisition; Developing countries; Gravimetric techniques; Hawaii; Iceland; Lava; LDCs; Magma; Magnetic data; Magnetic field; Magnetic fields; Magnetic measurement; Magnetic signals; magnetism; Magnetometers; Monitoring; Rock; Rocks; Seamounts; Tracking; Volcanic activity; Volcanic eruptions; volcanic hazards; Volcano monitoring; Volcanoes; volcanology
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2022GL100006

Monitoring of active volcanic systems is a challenging task due in part to the trade‐offs between collection of high‐quality data from multiple techniques and the high costs of acquiring such data. Here we show that magnetic data can be used to monitor volcanoes by producing similar data to gravimetric techniques at significantly lower cost. The premise of this technique is that magma and wall rock above the Curie temperature are magnetically “transparent,” but not stationary within the crust. Subsurface movements of magma can affect the crustal magnetic field measured at the surface. We construct highly simplified magnetic models of four volcanic systems: Mount Saint Helens (1980), Axial Seamount (2015–2020), Kīlauea (2018), and Bárðarbunga (2014). In all cases, observed or inferred changes to the magmatic system would have been detectable by modern magnetometers. Magnetic monitoring could become common practice at many volcanoes, particularly in developing nations with high volcanic risk. Plain Language Summary Scientists monitor volcanoes and try to predict volcanic eruptions using a variety of techniques. In this study, we show how a relatively inexpensive magnetometer can be used to monitor volcanoes by tracking magma movement below the surface. Rocks produce a magnetic signal that can be measured using a magnetometer, but magma produces no magnetic signal. We construct magnetic models showing that when magma migrates below the surface, it affects the magnetic field because it is displacing or melting the rocks. The volcanoes that we model are Mount St. Helens (pre‐1980 eruption), Axial Seamount (from 2015 to 2020), Kīlauea, Hawaii (pre‐2018 eruption), and Bárðarbunga (pre‐2014 eruption). Magnetic volcano monitoring may become standard practice at many volcanoes, particularly in developing nations with low monitoring budgets but high volcanic risk. Key Points Magnetic models of four volcanic systems are presented, showing that movement of magma produces measurable magnetic signals Magnetic data can be used for low‐cost volcano monitoring in a wide variety of settings and environmental conditions This monitoring technique has several advantages over existing methods, but consistent workflows and best‐practices need to be developed