Abstract: The paper is dedicated to Ruaumoko the Maori God of Volcanoes. To start with, a historical account  of some ancient legends regarding volcanoes is given. There is a description of eruption of a volcano with special reference to the eruption of Mount Vesuvius. Formation of magma in the Earth In the review of literature, some research papers of few eminent authors pertaining to volcanic eruption precursors, magma chambers  intrusion of magma, magma wagging, velocity of eruption and quantity of eruption are considered.

 Key Words: Dense Rock Equivalent, Eruption of Mount Vesuvius, Lava, Magma, Magma Chamber, Magma Reservoir, Magma wagging, Plate Tectonic theory, Ring of Fire, Volcanic eruptions, Volcanic Explosive Index (VEI)