It is difficult to distinguish an extinct volcano from a dormant ( inactive ) one . Dormant volcanoes are those that have not erupted for thousands of years , but are likely to erupt again in the future . Volcanoes are often considered to be extinct if there are no written records of its activity . Nevertheless , volcanoes may remain dormant for a long period of time . For example , Yellowstone has a repose/recharge period of around 700,000 years , and Toba of around 380,000 years . Vesuvius was described by Roman writers as having been covered with gardens and vineyards before its eruption of 79 CE , which destroyed the towns of Herculaneum and Pompeii . Before its catastrophic eruption of 1991 , Pinatubo was an inconspicuous volcano , unknown to most people in the surrounding areas . Two other examples are the long-dormant Soufrière Hills volcano on the island of Montserrat , thought to be extinct before activity resumed in 1995 , and Fourpeaked Mountain in Alaska , which , before its September 2006 eruption , had not erupted since before 8000 BCE and had long been thought to be extinct
eruption of 79 CE
Eruption of Mount Vesuvius in 79
Volcano