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Dike complexes, which are increasingly accepted as a common feature in the growth of most oceanic volcanoes, are well represented in the Canary Islands, where their deep structure can be readily observed through hundreds of infiltration galleries excavated for water mining. These intrusive complexes have their surficial representation as narrow, clearly aligned clusters of emission centers that, cumulatively, form steep topographic ridges. In the subsoil, a narrow band of tightly packed parallel dikes runs through the center of the structure. These volcanotectonic features behave as true active polygenetic volcanoes and show clear rift affinities. The geometry of these rift zones is either single or three-branched. The two-branched stage, probably transitional, has not been observed. The rift zones play a key role in the mass wasting and destruction of mature oceanic volcanoes. Cumulative gravitational stresses …