A volcanic eruption is marked by the discharge (aerially explosive) of fragmentary ejecta, lava and gases from a volcanic vent. A volcano is an opening, or rupture in the earth’s surface that allows hot magma, volcanic ash and gases to escape. They are generally found where tectonic plates come together or separate, although some occur in the middle of plates due to volcanic hotspots activity. The Hawaiian volcanic islands are one such example. Volcanoes provide a number of environmental benefits, for example: fertile soils, hydrothermal energy, precious minerals and tourism. However, they also pose several hazards: volcanic ash, gases, lahars, landslides, lava flows, and pyroclastic flows.