Yes, it definitely is possible. When a tank's ammo detonates, especially if it has its turret hatches closed (and secured), the turret may pop off because that's the easiest way for the pressure to get out. There are also photos from the 1991 Gulf War like that, because the Russian T-72 is especially vulnerable to this due to where its main ammo store is located (like [USER=22256]@Littlemarten[/USER] mentions above too): directly under the turret in a carrousel-type autoloader. Once that goes up, the pressure goes straight up into the turret.