This is the 7224th most frequent Russian word.
взрывом
"Взрывом" means "by an explosion" or "with an explosion" in English.
Here, 'взрывом' denotes the instrumental case of the word 'взрыв' (explosion), indicating the means by which the building was destroyed.
Огромное здание было разрушено взрывом.
The huge building was destroyed by the explosion.
In this context, 'взрыва' is in the genitive case, showing possession or relation of the explosion's power.
Учёный объяснил силу взрыва в своём докладе.
The scientist explained the power of the explosion in his report.
Here, 'взрыва' is in the genitive case, indicating the source or from what the soldiers are taking cover.