A careful analysis of low-frequency seismic events on Soufrièere Hills volcano, Montserrat, points to a source mechanism that is non-destructive, repetitive, and has a stationary source location. By combining these seismological clues with new field evidence and numerical magma flow modelling, we propose a seismic trigger model which is based on brittle failure of magma in the glass transition....

This article considers the iterative solution of a finite element discretisation of the magma dynamics equations. In simplified form, the magma dynamics equations share some features of the Stokes equations. We therefore formulate, analyse and numerically test a Elman, Silvester and Wathen-type block preconditioner for magma dynamics. We prove analytically and demonstrate numerically the optima...

We introduce MaGMA, a Mobility and Group Management Architecture, enabling realtime collaborative group applications such as push-to-talk (PTT) for mobile users. MaGMA provides, for the first time, a comprehensive and scalable solution for group management, seamless mobility, and quality-of-service (QoS). MaGMA is a distributed IP-based architecture consisting of an overlay server network deplo...

The Earth formed through accretion of planetesimals in 1–100 million years. Planetesimal impacts induce degassing, melting, and vaporization during accretion. The impact degassing, as well as the gravitational capture of the surrounding solar nebula gas, formed the proto-atmosphere on a growing Earth. The impact of heating and the blanketing effect of the proto-atmosphere resulted in the meltin...

The Indian Peak volcanic field is representative of the more than 50,000 km3 of ashflow tuff and tens of calderas in the Great Basin that formed during the Oligocene-early Miocene "ignimbrite flareup" in southwestern North America. The field formed about 32 to 27 Ma in the southeastern Great Basin and consists of the centrally positioned I n d i Peak caldera complex and a surrounding blanket of...

In this talk we consider numerical methods to efficiently solve the linear system arising from the discretization of models of coupled magma/mantle dynamics. The model we consider is based on a system of partial differential equations derived by McKenzie [1]. This system describes the creeping flow of high-viscosity mantle matrix and the porous flow of magma, a process which is described by a c...

Major volcano flank collapses strongly affect the underlying magmatic plumbing system. Here, we consider the magma storage zone as a liquid pocket embedded in an elastic medium, and we perform numerical simulations in two-dimensional axisymmetric geometry as well as in three dimensions in order to evaluate the consequences of a major collapse event. We quantify the pressure decrease induced wit...

The largest volcanic eruptions in the geologic record have no analogue in the historical record. These eruptions had global impacts1,2, but are known only through their eruptive products. They have left behind calderas that formed as the surface collapsed when eruption evacuated magma chambers at 5–15 km depths3,4. It is generally assumed that calderas reflect the spatial dimensions of underlyi...

[1] We investigate the plausibility of the stratified Boycott effect as a source of layering in magma chambers. Crystal settling within the magma chamber will generate buoyant fluid near the sloping sidewalls whose vertical ascent may be limited by the ambient stratification associated with vertical gradients in SiO2. The resulting flow may be marked by a layered structure, each layer taking th...

Volcanic ash is fragments of magma, and consists of minerals and volcanic glass. These materials in the ash can provide important information on the nature of the magma, because chemical compositions of magma usually show distinct features in each volcano, and because assemblages and compositions of minerals reflect their host melt. Using assemblages and chemical compositions of minerals and gl...