ption ▁column ▁( H B = 2 5   km ), ▁the ▁water ▁content ▁of ▁mag ma ▁( 1 – 2 % ), ▁and ▁the ▁temperature ▁of ▁mag ma ▁( 1 0 0 0 ▁k ) ▁indicate ▁that ▁radius ▁of ▁the ▁er u ption ▁vent ▁was ▁ 2 0 0 ▁m . ▁The ▁clim ax ▁of ▁the ▁er u ption ▁may ▁have ▁released ▁ 4 . 1 8 – 1 2 . 4 3 ▁× ▁ 1 0 1 9 ▁jou le , ▁and ▁the ▁er u ption ▁might ▁have ▁last ed ▁for ▁ 3 5 – 1 0 4 ▁hours . ▁ ▁Later ▁period ▁ ▁This ▁period ▁er u ption ▁formed ▁the ▁upper ▁part ▁of ▁the ▁Pl in ian ▁p um ice ▁fall , ▁which ▁is ▁the ▁fine ▁p um ice . ▁The ▁later ▁Pl in ian ▁p um ice ▁fall ▁and ▁py ro cl astic ▁flow ▁occurred ▁simultaneously , ▁because ▁some ▁sections ▁show ▁that ▁p um ice ▁fall ▁and ▁ign im br ite ▁are ▁inter le aved . ▁Com bin ing ▁the ▁gra in - size ▁of ▁p um ice ▁and ▁thick ness ▁of ▁p um ice ▁fall , ▁the ▁height ▁of ▁er u ption ▁column ▁of ▁later ▁period ▁was ▁no ▁higher ▁than ▁ 1 4   km ▁( H B = 1 0   km ), ▁and ▁the ▁mass ▁dis charge ▁rate ▁was ▁ 5 ▁× ▁ 1 0 6 ▁kg / s ▁( 5 ▁× ▁ 1 0 3 ▁m 3 / s ). ▁The ▁later ▁period ▁may ▁released