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

Abstract

Monitoring of active volcanoes is a challenging task due to unpredictable behavior of the magmatic system, lack of financial resources for monitoring, and a variety of other factors (Scarpa & Gasparini, 1996). These challenges are amplified when monitoring submarine volcanoes, which constitute the majority of volcanoes on earth (Crisp, 1984). For example, Axial Seamount is the best-instrumented submarine volcano in the world, but an eruption in 2011 was not identified until new lava flows were found 3 months later by the remotely operated vehicle Jason (W. W. Chadwick et al., 2012).The current array of volcano monitoring methods and techniques is vast and impressive, and it is clear that a monitoring network that uses many techniques is the most effective approach (Miller & Jolly, 2014;Scarpa & Gasparini, 1996). Seismic monitoring is a popular method to detect unrest via small earthquakes and tremors that are associated with magma movement (McNutt & Roman, 2015). However, magma can move aseismically, particularly if ascent is slow (Lu et al., 2000;Roman & Cashman, 2018). Gravity measurements are the most powerful technique that is currently available, as changes to the crustal gravity field are unambiguously associated with changes to the magmatic system (Battaglia et al., 2008;Carbone et al., 2019). However, high-quality gravimetric monitoring can cost hundreds of thousands of dollars for the instruments alone (Fernández et al., 2017). Current volcano monitoring programs could benefit from a method that is similar to gravimetry but operates at a much lower cost.

The Magnetization of an Underwater Caldera: A Time‐Lapse Magnetic Anomaly Study of Axial Seamount

“…This is consistent with independent geophysical data (Chadwick et al, 2022) which shows that Axial, while it has inflated to ∼90% of its pre-eruption level, has a magma supply rate that has been waning since the last eruption in 2015, so that any future eruption is still years away. Furthermore, magnetic modeling of Axial Seamount (Biasi et al, 2022) shows that while a thermal zone extends beyond the magma body itself, the northern part of the caldera needed extensive cooling to replicate the results reported here.…”

“…This thermally demagnetized zone may grow prior to an impending eruption due to the inflation of the magma chamber that is known to occur prior to eruptions (Chadwick et al., 2022; Nooner & Chadwick, 2016). If true, we may be able to measure magnetic changes in this zone as it enlarges (Biasi et al., 2022). However, it is also possible that seawater circulation within the shallow fractured crust overlying the magma chamber would keep the crust cool creating a cold lid that would restrict the extent of the thermal zone to some depth and may only change once lava has erupted to the surface.…”

“…Our data analysis may help determine which of these thermal zone hypotheses is supported by evidence. Furthermore, if successful, magnetic surveys may provide a low‐cost and efficient method for gathering frequent temporal data in comparison to other forms of geophysical surveys (Biasi et al., 2022), and could provide valuable insights into the internal workings of Axial Seamount.…”

“…More recent seismic imaging of Axial confirms the presence of an elongate magma chamber (MMR in Figure 1) beneath the summit caldera of Axial (Arnulf et al, 2014(Arnulf et al, , 2018Carbotte et al, 2020) and a smaller secondary reservoir to the east (SMR in Figure 1). The thermal signature of the main magma chamber, the internal lava feeder system, and the slow re-inflation of the summit since 2015 may be detectable using magnetic fields (Biasi et al, 2022). Here, we present the first study of temporal magnetic imaging using repeat surveys of high-resolution, near-bottom magnetic data gathered over the summit of Axial Seamount since 2015 with the autonomous underwater vehicle (AUV) Sentry.…”

The Subsurface Structure of the Kīlauea Caldera Before Its 2018 Collapse Inferred From Ground Magnetic, SP, and Temperatures Anomalies

“…Future magnetic studies at Kīlauea should now focus on monitoring geomagnetic field variations associated to the evolution of the volcanic system since the 2018 crisis. Studying the evolution of magnetic anomalies within volcanic edifices will help to highlight spatio‐temporal changes in magmatic and hydrothermal dynamics, mechanical processes and weakness zones (Biasi et al., 2022; Gailler & Kauahikaua, 2017). Promising ongoing studies are in progress, for example, at the scale of Piton de la Fournaise (Réunion Island) where the evolution of the volcanic activity is associated with volcano‐magnetic variations (Zlotnicki et al., 1993).…”