The Influence of Plumbing System Structure on Volcano Dimensions and Topography

Abstract

Volcano morphology has been traditionally studied from a descriptive point of view, but inthis work we took a different more quantitative perspective. Here we used volcano dimensions such asheight and basal radius, together with the topographic profile as indicators of key plumbing systemproperties. We started by coupling models for the ascent of magma and extrusion of lavaflows withthose for volcano edifice construction. We modeled volcanic edifices as a pile of lavas that are emittedfrom a single vent and reduce in volume with time. We then selected a number of arc-volcano examplesto test our physical relationships and estimate parameters, which were compared with independentmethods. Our results indicate that large volcanoes (>2,000 m height and base radius>10 km) usually arebasaltic systems with overpressured sources located at more than 15 km depth. On the other hand,smaller volcanoes (<2,000 m height and basal radius<10 km) are associated with more evolved systemswhere the chambers feeding eruptions are located at shallower levels in the crust (<10 km). Wefind thatsurface observations on height and basal radius of a volcano and its lavas can give estimates offundamental properties of the plumbing system, specifically the depth and size of the magma chamberfeeding eruptions, as the structure of the magmatic system determines the morphology of thevolcanic edifice.