The author deeply studied cooling unit of pyroclastic flow in Luanping area and divided the volcanic rock into 12 cooling units.

笔者对滦平地区火山碎屑流冷却单元进行了深入的研究，划分出12个冷却单元。

The eruption seems to have started with the volcano spitting out lumps of rock up to 2 metres across, before releasing an enormous pyroclastic flow - a fast-moving gush of hot gas and rock.

火山似乎在释放出巨大的火山碎屑流(一种热的气体和岩石快速移动的喷流)之前，从开始吐出2米宽度的岩石块而开始爆发。