1.
If a gun, or a person firing a gun, blasts away , the gun is fired continuously for a period of time.
Suddenly all the men pull out pistols and begin blasting away.
PHRASAL VERB : V P
2.
If something such as a radio or a pop group is blasting away , it is producing a loud noise.
Clock-radios blast away until you get up.
= blare out
PHRASAL VERB : V P