Amy G. Ryan, James K. Russell, Michael J. Heap, Mark E. Zimmerman, and Fabian B. Wadsworth

Whether volcanoes will erupt explosively depends on the behavior of gases trapped in the subsurface. If gas pressures are high within a volcano, the surrounding magma and rocks can break, causing explosive eruptions. Alternatively, if gases vent to the surface through interconnected void spaces, explosive behavior does not occur. Void spaces in volcanoes are ephemeral – numerous processes can close them. Here we show that solid state sintering – a historically neglected process – operates pervasively and efficiently within volcanic conduits. We use high-temperature-pressure experiments and models to characterize and understand the timescales of this process under typical volcanic conditions. Our resarch shows the timescales (days to weeks) to be commensurate with the periodicity of explosive eruptions during lava dome producing eruptions.