Extreme Curvature of Shallow Magma Pathways Controlled by Competing Stresses: Insights From the 2018 Sierra Negra Eruption

Eruptions at shield volcanoes often occur from radially aligned linear fissures fed by blade-like magma-filled cracks (dykes). The of the 2018 Sierra Negra eruption were scattered on flank volcano. Space-borne radar interferometric data (interferometric synthetic aperture radar) revealed that, unexpectedly, part was a 15 km long, tortuous and flat-lying crack (sill). Here we develop framework that captures full three-dimensional (3D) kinematics non-planar intrusions. This includes both an analytical comprehensive numerical scheme. We constrain models such they match observed ground deformation Negra. show peculiar sill trajectory is due to competing stress gradient magnitudes being close one another throughout its propagation. By accounting for interaction all these factors, 3D open possibility understand simulate geometry magma transport volcanic systems.