Videos show no indication of a secondary detonation of that size (or at all). It's a single large primary strike. Moreover, Hamas does not have the capability to launch a rocket with this explosive capacity. Hamas' best rocket is the Ayyash 250, which wouldn't even come close to this much damage. The amount of damage in this strike is much more in line with an American ATACMS or a Russian Iskander (and, in fact, seems larger) and Hamas is decades from developing that capability. It's far more likely to be a large guided munition like a JDAM.

The Russia-Ukraine war has shown has plenty of examples of what happens when you strike an ammo depot. You're free to compare for yourself.