In order to be considered active, a volcano must have erupted within the last few thousand years. On the Earth today there are around 560 active volcanoes. Each week 15 – 20 of these volcanoes will erupt. Each year two or three volcanoes erupt that were previously thought to be dead.
Some volcanoes last for hundreds of thousands of years, while others are born, and die within a matter of only a few decades. While old volcanoes are constantly dying, new volcanoes are being created. One such event took place in a farmer’s field in Mexico in 1943. Within a nine year period a new volcano formed, building a large mountain, where no previous volcano existed. In 1964 a similar eruption took place in the ocean off the coast of Iceland. This eruption and subsequent eruptions have created a large island, where there was previously only ocean water.