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Volcanoes erupt because of density and pressure. The lower density of the magma relative to the surrounding rocks causes it to rise (like air bubbles in syrup).


A volcano begins as melted rock (magma) which rises from deep inside the earth toward the surface. As the gas-filled magma rises ...


When a part of the earth's upper mantle or lower crust melts, magma forms. A volcano is essentially an opening or a vent through which this magma and the ...


Aug 4, 2015 ... It is increased magma movement within a volcano that causes an eruption. These movements are triggered by different processes that happen ...


Jan 5, 2015 ... The eruption of a volcano can be one of the planet's most destructive events — spewing huge amounts of rock, gas and ash that can kill people.


There are few geological events that are as dramatic as a volcanic eruption except maybe a hurricane, tornado or a tsunami. Each is drama.


A secondary school revision resource for GCSE Geography covering key facts about volcanoes and volcanic eruptions.


Jan 6, 2016 ... A team of volcanologists led by the University of Liverpool have released a perhaps controversial Nature study on the causes of volcanic ...


Nov 30, 2010 ... It's time for our weekly Just Ask feature, where the experts tackle your questions on science and technology. John Eichelberger, a volcano ...