Stacked sills forming a deep melt-mush feeder conduit beneath Axial Seamount

Magmatic systems are composed of melt accumulations and crystal mush that evolve with melt transport, contributing to igneous processes, volcano dynamics, and eruption triggering. Geophysical studies of active volcanoes have revealed details of shallow-level melt reservoirs, but little is known about fine-scale melt distribution at deeper levels dominated by crystal mush. Here, we present new seismic reflection images from Axial Seamount, northeastern Pacific Ocean, revealing a 3–5-km-wide conduit of vertically stacked melt lenses, with near-regular spacing of 300–450 m extending into the inferred mush zone of the mid-to-lower crust. This column of lenses underlies the shallowest melt-rich portion of the upper-crustal magma reservoir, where three dike intrusion and eruption events initiated. The pipe-like zone is similar in geometry and depth extent to the volcano inflation source modeled from geodetic records, and we infer that melt ascent by porous flow focused within the melt lens conduit led to the inflation-triggered eruptions. The multiple near-horizontal lenses are interpreted as melt-rich layers formed via mush compaction, an interpretation supported by one-dimensional numerical models of porous flow in a viscoelastic matrix.

Supplemental Material: Stacked sills forming a deep melt-mush feeder conduit beneath Axial Seamount

Discussion of potential artifacts to aid interpretation of seismic data; discussion of one-dimensional finite element model for multi-phase flow in a viscoelastic matrix including model parameters used; Figures S1–S6 including post stack time emigration images for lines 38, 48, and 51; partial offset stacks; pre-stack data examples; and velocity models used for reverse-time migration.<br>

Supplemental Material: Stacked sills forming a deep melt-mush feeder conduit beneath Axial Seamount

Discussion of potential artifacts to aid interpretation of seismic data; discussion of one-dimensional finite element model for multi-phase flow in a viscoelastic matrix including model parameters used; Figures S1–S6 including post stack time emigration images for lines 38, 48, and 51; partial offset stacks; pre-stack data examples; and velocity models used for reverse-time migration.<br>

Supplemental Material: Stacked sills forming a deep melt-mush feeder conduit beneath Axial Seamount

Discussion of potential artifacts to aid interpretation of seismic data; discussion of one-dimensional finite element model for multi-phase flow in a viscoelastic matrix including model parameters used; Figures S1–S6 including post stack time emigration images for lines 38, 48, and 51; partial offset stacks; pre-stack data examples; and velocity models used for reverse-time migration.<br>

Rheology of non-colloidal suspensions with viscoelastic matrices

The rheology of non-colloidal suspensions of spheres in a viscoelastic matrix, including the viscometric, G′, G′ and uniaxial extensional responses, is explored.