2004 Indian Ocean earthquake and tsunami and a network of sensors is needed to detect it. Setting up the communications infrastructure to issue timely warnings is an even bigger problem, particularly in a relatively impoverished part of the world. Tsunamis are more frequent in the Pacific Ocean than in other oceans because of earthquakes in the "Ring of Fire". Although the extreme western edge of the Ring of Fire extends into the Indian Ocean (the point where the earthquake struck), no warning system exists in that ocean. Tsunamis there are relatively rare despite earthquakes being relatively frequent in Indonesia. The last major tsunami was caused by
Ring of Gullion similar structures had been described from Scotland. It was emplaced during the Paleogene opening of the Atlantic Ocean during the formation of the North Atlantic Igneous Province. The structure of the ring dyke was produced when the active volcano's caldera underwent collapse producing a concentric suite of faults providing space into which magma was able to intrude. The ring dyke is composite with both porphyritic granophyre and porphyritic felsite components. The composition of the remainder of the volcano today is dominated by gabbro and granophyre and is also the site of a noted occurrence of platinum group elements. The rocks