Volcanoes on land often take the form of flat cones, as the expulsions build up over the years. Under water, volcanoes often form rather steep pillars? and in due time break the ocean surface in new islands.
Science has not yet been able to predict with absolute certainty when a volcanic eruption will take place, but significant progress in judging when one is probable has been made in recent time.
Volcanic activity is often accompanied by earthquakes, [hot springs]? and geysers?. Famous volcanoes include [Mount Aetna]?, [Mount Hekla]?, Vesuvius?, and [Mount Fuji]?.
Public domain picture from NASA
Anyone know what volcano this is? I'm guessing Mt St Helens...NO-it's Tambora, Indonesia