why couldn't Axel hear the the explosion ?

the visual situation attracted him more than the the sound of explosion "the shape of the rocks changed before my eyes

Because they were far from the rock , so they could see but couldn't hear the explosion.

He was far from the explosion >>>>His eyes were attracted by the scene of the lava and rocks>>>>>He fainted .too

he had fainted

there was water behind the rock

ecause they were far from the rock , so they could see but couldn't hear the explosion.

this is the answer
Because he was focusing on the shape of the rock and what would happen to it .

لانها موجات فوق سمعية
it was so loud more than the human can hear

I think Because the explosion happened in the tunnel and this muffled the sound

thanks very much