Ring of Fire volcanic eruptions of the last 11,700 years occurred at volcanoes in the Ring of Fire. The Ring of Fire is a direct result of plate tectonics: the movement and collisions of lithospheric plates, especially subduction in the northern portion. The southern portion is more complex, with a number of smaller tectonic plates in collision with the Pacific plate from the Mariana Islands, the Philippines, Bougainville, Tonga, and New Zealand. The presence of a belt of volcanic activity surrounding the Pacific Ocean was observed in the 19th century. "They [the Japanese Islands] are in the line of that immense circle of
Warm core ring Warm core ring A warm core ring is a type of mesoscale eddy which breaks off from an ocean current, e.g. the Gulf Stream or the Kuroshio Current. The ring is an independent circulatory system of warm water which can persist for several months. The rest of this article will use the Gulf Stream by way of an example but these mesoscale eddies also form in most powerful ocean currents, such as the Kuroshio or Agulhas currents. Such rings can be detected using infrared satellites or sea height anomalies and are easily identifiable against the surrounding colder waters. These systems