Stress inversions to forecast magma pathways and eruptive vent location

Abstract

When a batch of magma reaches Earth’s surface, it forms a vent from which volcanic products are erupted. At many volcanoes, successive batches may open vents far away from previous ones, resulting in scattered, sometimes seemingly random spatial distributions. This exposes vast areas to volcanic hazards and makes forecasting difficult. Here, we show that magma pathways and thus future vent locations may be forecast by combining the physics of magma transport with a Monte Carlo inversion scheme for the volcano stress history. We validate our approach on a densely populated active volcanic field, Campi Flegrei (Italy), where we forecast future vents on an onshore semiannular belt located between 2.3 and 4.2 km from the caldera center. Our approach offers a mechanical explanation for the vent migration over time at Campi Flegrei and at many calderas worldwide and may be applicable to volcanoes of any type.

Radial interpolation of GPS and leveling data of ground deformation in a resurgent caldera: application to Campi Flegrei (Italy)

“…It is a good proxy of the ground surface extension, which may eventually lead to an increase in the secondary permeability by fracturing and hence of degassing and, in extreme cases, to the opening of new volcanic vents/ fissures. Numerical models and experimental studies showed that dyke propagation is influenced by the local properties of the stress field and by preexisting fractures (Gaffney et al 2007;Maccaferri et al 2011;Le Corvec et al 2013;Corbi et al 2015Corbi et al , 2016Rivalta et al 2019). For the specific case of Campi Flegrei, the maps indicate that the maximum horizontal displacements are located over a semicircular annular region, with a radius of about 2-3 km from the town of Pozzuoli.…”

“…Blue dots mark the RIM virtual displacement locations, along elliptic arcs. UTM WGS84, Zone 33 N coordinate system (m) 3D deformation field can help to constrain the expected radial distance of eruptive vents from the center of the caldera, and large values of horizontal deformation can be used as a spatial precursor to future vent opening (see Bevilacqua et al 2015Bevilacqua et al , 2017Rivalta et al 2019;Patra et al 2019).…”

Extreme curvature of shallow magma pathways controlled by competing stresses

“…In order to understand why the sill turned as observed, before proceeding with a 3D simulation, we reduce the physics of this problem to its component parts and evaluate how these affect the sill's direction of propagation. Previous studies have found that dyke trajectories are dependent on the ratio of tectonic to topographic loading stresses 3,6,7 . Here we propose that contrasting magma and rock weight gradients (buoyancy) must also be considered as one of the dominant forces.…”

Partly Cloudy With a Chance of Lava Flows: Forecasting Volcanic Eruptions in the Twenty‐First Century

“…One such model (Mastin et al, 2008) was even used during the 2004-2008 eruption of Mount St. Helens to forecast the final volume of the eruption (Mastin et al, 2009), and a volcano-like chamber-conduit model was used to forecast the duration of the Lusi mud eruption in Indonesia (Rudolph et al, 2011). Models of magma transport that account for a volcano's stress history can even forecast the location of future eruptive vents (Rivalta et al, 2019).…”