Fig. 5: Schematic illustration of our proposed bottom-up mechanism for correlated deformation at Galápagos volcanoes.

The recent melt flux to each volcano (Fig. 3) is represented by the width of hatched areas, with Sierra Negra accounting for an average of 55% of the total supply since 2000 (Fig. 4). Each volcano samples a geochemically distinct area of the Galápagos plume, where local compositional variations control supply⁴², though there may be occasional mingling between heterogeneous magma batches¹⁸. Connectivity occurs at the base of the crust through pore-pressure stress transfer between geochemically distinct sills^28,34. The flux of magma to the shallow crust, causing measurable deformation, varies in magnitude and partitioning according to a combination of plume supply variations and eruption, as illustrated in Fig. 4.