In ancient times, Greeks believed that volcanic eruptions were due to anger of Goddess ‘Vulcan’, living under the Mt.Vulcan (Lipari Islands near Sicili of Italy). People thought that volcano was the mountain of fire. Causes of Volcano: The volcanic eruptions are closely associated with various causes.

• Gases and water vapour formed due to heating of underground water. 
• Movement and breaking of major and minor plates of the Earth. 
• Ascent of magma forced by excess pressure. 
• The temperature inside the Earth increases with the increasing depth 1°C per 32m). 
• Formation of magma because of increase in temperature and reduction in pressure.

Effects of volcanoes: 

• Volcanoes are natural hazard and disaster which cause extensive damage to life and property. 
• Volcanoes cause damage to agricultural fields, industries, dwellings, buildings, roads, railways, airports, dams, reservoirs etc. 
• Volcanoes cause diversion of river course and flooding of water. 
• Volcanic dust, ash and smoke cause air pollution. 
• Volcanic eruption sometimes produce seismic waves.