ABSTRACT
Hydrovolcanic landforms develop when an external source of water interacts with magma approaching the Earth’s surface. The large areas covered by water, ice, snow, and frozen ground, abundant precipitation, and subsurface aquifers, as well as innumerable paths provided by fractures in the Earth’s crust, all combine to ensure that some interaction between water and magma during most volcanic eruptions is almost inevitable at present. It was even more likely to have occurred during the ice ages in the past 2 million years when ice-sheets and glaciers expanded and wetter pluvial periods in semi-arid areas often led to the formation of large lakes, notably in the American West.
