Interesting questions asked here. The big one though, is just how is it possible for a planet to explode at all. Assuming only a third of the mass is involved to make the whole exercise worthwhile, all that mass M must achieve a velocity able to remove it from the planet's center of mass but also outside the planetary orbit itself.
The only prospective planet is actually Mars. It requires the elimination of gravity over a large enough disc to allow all material to migrate to the ejection jet so formed. Olympus Mons looks like the remnant of such a jet and exploding and pop corning rock would fill the jet to possibly produce the asteroid belt..
This is the best explanation for Olympus Mons i have come up with so far. Add in all the rock used for the early bombardment event and we likely have another Earth originally. My real point though is that no chemical process caused any of this. So all that explosive record may be produced by gravity manipulation to engineer this solar system.
This could also be a lot more recent than we expect as well.
Astonishing ‘Explosions’ and Surprising Shifts in the Planet’s History
By Tara MacIsaac, Epoch Times | January 22, 2015