Another way a volcanic eruption will happen is when water underneath the surface interacts with hot magma and creates steam, this can build up enough pressure to cause an explosion. According to the national geographic, another way volcanoes can form is what's known as hotspot volcanism. According to weatherwizkids, an active volcano is one which has recently erupted and there is a possibility that it may erupt soon. An extinct volcano is one which has erupted thousands of years ago and there’s no possibility of eruption. There are more than 1500 active volcanoes on the Earth.

Source: The Star May 24, 2021 10:18 UTC