Pyroclastic surges are super-heated winds of ash, rock, and volcanic gases.

火山碎屑潮是火山灰、岩石和火山气体的过热风。

Hot ash and noxious gas billow out in a wave known as a pyroclastic surge.

炽热的火山灰和有毒气体以一种被称为火山碎屑潮的波浪形式涌出。

People were  either buried alive in the ash or were instantly killed by the pyroclastic surges.

人们要么被活埋在火山灰中，要么立即被火山碎屑浪潮杀死。

Another pyroclastic surge rushes across the valley, crashes into Pompei, and sheers off the upper levels of the town's buildings.

另一股火山碎屑涌动冲过山谷，冲入庞贝，并从该镇建筑物的上层滑落。

These include the ash, which  historians believe fell at a rate of four to six inches an hour, and the pyroclastic surges.

其中包括火山灰，历史学家认为火山灰以每小时 4 到 6 英寸的速度下落，以及火山碎屑的涌动。