Where the dike breaches the surface, a fissure eruption occurs. Initially, surface flows will erupt along the length of the fissure. Eruption conditions rapidly evolve, however. Seamounts are produced when the eruption centralizes to a single vent. The seamount at the front edge of the cartoon is shown to indicate that fissures may evolve quickly to produce only a seamount, and fissures may be covered by their products.
Illumination is from the right.
The area of the image is 3 km east to west, and 5 km north to south. A string of hummock-sized cones has been built. Although many of these cones have been partially destroyed, individual edifices can be identified. We envision that, similar to magma transport in subaerial volcanic rift zones, magma is transported from the regions of accumulation for example, in the shallow mantle, at the base of the crust, or within the crust to the seafloor through dikes by a combination of lateral and vertical motion. Where the dike intersects the seafloor, a fissure eruption begins.