Stress Control of Dike Deflection and Flank Eruption at Akaroa Volcano, New Zealand.

Understanding the stress evolution of extinct volcanoes can improve efforts to forecast flank eruptions on active systems. Field, petrographic, and seismic data are combined with numerical modeling to investigate the paleo-stress field of New Zealand's Akaroa Volcano, or Akaroa Volcanic Complex. Field mapping identifies 86 radially oriented dikes and seven lava domes found only within a narrow elevation range along Akaroa's erosional crater rim.

Forecasting mechanical failure and the 26 June 2018 eruption of Sierra Negra Volcano, Galápagos, Ecuador.

Using recent advancements in high-performance computing data assimilation to combine satellite InSAR data with numerical models, the prolonged unrest of the Sierra Negra volcano in the Galápagos was tracked to provide a fortuitous, but successful, forecast 5 months in advance of the 26 June 2018 eruption. Subsequent numerical simulations reveal that the evolution of the stress state in the host rock surrounding the Sierra Negra magma system likely controlled eruption timing. While changes in magma reservoir pressure remained modest (<15 MPa), modeled widespread Mohr-Coulomb failure is coincident with the timing of the 26 June 2018 moment magnitude 5.

Triggering of eruptions at Axial Seamount, Juan de Fuca Ridge.

The submarine volcano Axial Seamount has exhibited an inflation predictable eruption cycle, which allowed for the successful forecast of its 2015 eruption. However, the exact triggering mechanism of its eruptions remains ambiguous. The inflation predictable eruption pattern suggests a magma reservoir pressure threshold at which eruptions occur, and as such, an overpressure eruption triggering mechanism.

Magma injection into a long-lived reservoir to explain geodetically measured uplift: Application to the 2007-2014 unrest episode at Laguna del Maule volcanic field, Chile.

Moving beyond the widely used kinematic models for the deformation sources, we present a new dynamic model to describe the process of injecting magma into an existing magma reservoir. To validate this model, we derive an analytical solution and compare its results to those calculated using the Finite Element Method. A Newtonian fluid characterized by its viscosity, density, and overpressure (relative to the lithostatic value) flows through a vertical conduit, intruding into a reservoir embedded in an elastic domain, leading to an increase in reservoir pressure and time-dependent surface deformation.

Spreading rate dependence of gravity anomalies along oceanic transform faults.

Mid-ocean ridge morphology and crustal accretion are known to depend on the spreading rate of the ridge. Slow-spreading mid-ocean-ridge segments exhibit significant crustal thinning towards transform and non-transform offsets, which is thought to arise from a three-dimensional process of buoyant mantle upwelling and melt migration focused beneath the centres of ridge segments. In contrast, fast-spreading mid-ocean ridges are characterized by smaller, segment-scale variations in crustal thickness, which reflect more uniform mantle upwelling beneath the ridge axis.