Eruption column heights are a useful way of measuring eruption intensity since for a given atmospheric temperature, the column height is proportional to the fourth root of the mass eruption rate. Consequently, given similar conditions, to double the column height requires an eruption ejecting 16 times as much material per second. The column height of eruptions which have not been observed can be estimated by mapping the "maximum" distance that pyroclasts of different sizes are carried from the vent—the higher the column the further ejected material of a particular mass (and therefore size) can be carried.