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Numerical simulations of volcanic processes play a fundamental role in understanding the dynamics of magma storage, ascent, and eruption. The recent extraordinary progress in computer performance and improvements in numerical modeling techniques allow simulating multiphase systems in mechanical and thermodynamical disequilibrium. Nonetheless, the growing complexity of these simulations requires the development of flexible computational tools that can easily switch between sub-models and solution techniques. In this work we present MagmaFOAM, a library based on the open-source computational fluid dynamics software OpenFOAM that incorporates models for solving the dynamics of multiphase, multicomponent magmatic systems. Retaining the modular structure of OpenFOAM, MagmaFOAM allows runtime selection of the solution technique depending on the physics of the specific process and sets a solid framework for in-house and community model development, testing, and comparison. MagmaFOAM models thermomechanical nonequilibrium phase coupling and phase change, and it implements state-of-the-art multiple volatile saturation models and constitutive equations with composition-dependent and space–time local computation of thermodynamic and transport properties. Code testing is performed using different multiphase modeling approaches for processes relevant to magmatic systems: Rayleigh–Taylor instability for buoyancy-driven magmatic processes, multiphase shock tube simulations propaedeutical to conduit dynamics studies, and bubble growth and breakage in basaltic melts. Benchmark simulations illustrate the capabilities and potential of MagmaFOAM to account for the variety of nonlinear physical and thermodynamical processes characterizing the dynamics of volcanic systems. [ABSTRACT FROM AUTHOR]

Explosive eruptions are the final result of complex dynamics occurring within the volcanic plumbing system and involving domains such as one or more magma chambers, their connecting dykes, and the conduit or dyke connecting magma with the surface. We present here a 1D quasi-steady numerical modeling approach that allows the interplay between magmatic reservoirs located at different depths to be taken into account in the analysis of the eruption dynamics. We simulate a set up, common to a large number of real eruption cases, where a shallow, relatively small magma chamber hosting partially degassed, chemically more evolved magma is connected through a dyke to a deeper, much larger, gas-rich, less differentiated magmatic body. The numerical results describe two separate regimes controlled by either the shallow or the deep magma reservoir. While the shallow-controlled regime shows a general increase of eruption magnitude with increasing volume of magma stored at shallow depth, the deep-controlled regime, that we associate to the potential occurrence of a large caldera collapse, lacks such a relationship, resulting in eruption magnitudes that are substantially independent from the volume of the shallow magma reservoir. The efficiency of the deep interconnections between magmatic reservoirs, exemplified in our simulations by the width of the interconnecting dyke, is found to be a major factor controlling the shift from one regime to the other. [ABSTRACT FROM AUTHOR]

Eruption products of individual volcanic eruptions commonly display heterogeneities that are often interpreted as evidence of short times from new magma arrival to eruption. The time evolution of magma mixing and the degree of homogenization are still not well understood. We present the results of a parametric study through numerical simulations of andesite-dacite buoyancy driven magma mixing, by varying viscosity and volatile contents. The results show that highly efficient buoyancy-driven mixing is followed by a phase where stable convective layers develop, and mixing becomes progressively less efficient. Low viscosity and more volatiles favor mixing and achievement of a higher level of homogenization. On the contrary, high viscosity and lower volatiles give rise to long lived heterogeneities, in some cases preserving the end member compositions. Analysis of the results suggest that during the early transient phase of efficient magma mixing, crystal dissolution dominates; however, for cases where the transient phase takes longer, growth and resorption can act together, likely resulting in multiple resorption surfaces and zoning patterns before stable conditions are reached and euhedral crystal growth takes place. Crystals initially in equilibrium with magma can display a range of textural evolutions depending on their initial composition and individual paths during one single event of magma recharge, convection and mixing. Overall, the numerical simulations suggest that complex patterns of growth and dissolution followed by euhedral rims of various composition can be associated with single recharging events; and that short reaction times do not necessarily reflect comparably short times from recharge to eruption. [ABSTRACT FROM AUTHOR]

The recent development and analysis of global databases of continental volcanic eruptions is increasingly providing new understanding of their global time-size distribution and of the global rates of volcanism on Earth. We now know that volcanic eruptions are globally Poissonian (memoryless) events, implying that previously widespread concepts such as that of retarding or "overdue" events are actually meaningless when referred to volcanic eruptions; and we have discovered a power law relationships between the size of explosive volcanic eruptions (VEI = Volcanic Explosivity Index equal or larger than 3) and their frequency, possibly placing a theoretical limit to our capability to anticipate the occurrence of a volcanic eruption of a given size, e.g., the occurrence of a cataclysmic super-eruption. Maximum likelihood estimates of rate parameters associated with exponentially-distributed inter-event eruption times allow global volcanic hazard and global rates of continental volcanism to be quantified over different time windows. Here I present the results of a Monte Carlo simulation showing the distribution of the global rates of continental volcanism over different time windows from 1 to 100,000 years. The new estimates presented here can be used as robust constraints for geodynamic models, e.g., models of plume dynamics and mantle-crust interaction, as well as for atmospheric evolution and climate change models. [ABSTRACT FROM AUTHOR]

An introduction to the journal is presented in which the editors discuss the announcement of media and information company Thomson Reuters to include the journal in their ISI listings and acknowledge the Copernicus Publications and the authors who contributed to the success of the journal.

The article offers the author's insights on the journal "Solid Earth Discussions" which is included in the ISI listings of multinational media and information firm Thomson Reuters. The author states that being included in the ISI listings is an excellent news for the journal and reflects the efforts of the editorial board. He adds that Thomson Reuters will be backdating the listing to the journal's first issue.