Long-term volcanism in locations without relation to the borders of continental plates.

Most volcanoes on earth are caused by the continental drift and are located at the margins of the continental plates. In contrast to these, some volcanoes are caused by updwelling, hot magma plumes from the mantle. The position of these processes remains unchanged, even when the crust is drifting over the hot mantle plumes. In this case (for example in the case of Hawaii), volcanic chains of islands are formed. In contrast to volcanoes adjacent to deep-sea trenches, the magma from hotspot volcanoes is more or less fluid, resulting in the continous flow of magma without larger explosive episodes.