A Textural Perspective on the Magmatic System and Eruptive Behaviour of Merapi Volcano

Quantitative textural analysis of crystals, including their number density, shapes, sizes, overall abundance and size distribution can be used to shed light on magmatic processes the timescales over which they operate. At Merapi, phenocrysts in dome lavas, lava flows, tephra, plutonic cumulates has revealed that open system steady state conditions prevail throughout crustal magma plumbing short time periods, with non-steady prevailing longer term. Phenocryst crystallisation likely takes place tens hundreds years prior eruption. feldspar microlites, conjunction compositional data, elucidate ascent degassing within conduit during forming eruptions, additionally reveal driving forces behind transitions between effusive explosive eruptive behaviour. For example, microlite textures from different stages 2010 eruption show activity were driven primarily by dynamics shallow conduit.