Lava either flow through breaks in the crater wall or from fissures on the flanks of the cone. Lava, solidified within the fissures, form dikes that act as ribs which help to strengthen the cone. They may rise as much as 8,000 feet above their bases. Depending on the type of volcanic material it is composed of, some can grow to such heights that their slopes become unstable and are susceptible to collapse from the pull of gravity. When volcanic activity ceases, erosion begins to destroy the cone.
Some composite volcanoes occur in chains and are separated by several tens of kilometers.