Complex sentence: The Volcanic Explosivity Index (VEI) is used to quantify the amount of ejected material with a VEI-7 being 100 km 3; every index value below that is one order of magnitude (meaning, ten times) less.
Split into simpler sentences: The Volcanic Explosivity Index (VEI) is used to quantify the amount of ejected material with a VEI-7 being. Every index value below that is one order of magnitude (meaning, ten times) less.