Dormant volcanos are the volcanos that are quiet but might erupt again in the future.[1] If a volcano that has been silent for years erupts again or shows activity, it is called a "dormant volcano". Vesuvius of Italy is a prime example. After many years of dormancy, it re-emerged in 1931. Then it is dormant again. For example, Krakatoa in Indonesia, Aconcagua in Argentina, and Mount Fuji in Japan are dormant volcanoes.
↑The plural of volcano can be either volcanos or volcanoes. Both are equally correct, and it is not a matter of British vs US spelling. Oxford English Dictionary. Spelling in any particular Simple page tries to be consistent.