A SUPER-VOLCANO in California which erupted with devastating results hundreds of thousands of years ago has a vast reservoir of semi-molten magma measuring a staggering 240 cubic MILES. The amount of magma in the Long Valley Caldera is so large it could support an eruption equivalent to the massive one which occurred 767,000 years ago, … Continue reading The amount of magma in the Long Valley Caldera is so large it could releases 140 cubic miles of material into the atmosphere during its next eruption