Enhancement of eruption explosivity by heterogeneous bubble nucleation triggered by magma mingling

Paredes-Mariño, Joali and Dobson, Katherine J. and Ortenzi, Gianluigi and Kueppers, Ulrich and Morgavi, Daniele and Petrelli, Maurizio and Hess, Kai-Uwe and Laeger, Kathrin and Porreca, Massimiliano and Pimentel, Adriano and Perugini, Diego (2017) Enhancement of eruption explosivity by heterogeneous bubble nucleation triggered by magma mingling. Scientific Reports, 7. 16897. ISSN 2045-2322

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    Abstract

    We present new evidence that shows magma mingling can be a key process during highly explosive eruptions. Using fractal analysis of the size distribution of trachybasaltic fragments found on the inner walls of bubbles in trachytic pumices, we show that the more mafic component underwent fracturing during quenching against the trachyte. We propose a new mechanism for how this magmatic interaction at depth triggered rapid heterogeneous bubble nucleation and growth and could have enhanced eruption explosivity. We argue that the data support a further, and hitherto unreported contribution of magma mingling to highly explosive eruptions. This has implications for hazard assessment for those volcanoes in which evidence of magma mingling exists.