It seem to "clean" to be a collapse. Shouldn't there be rubble, broken surfaces, cracks, fissuring? Seems to well sculpted to be any of that.

There's also non-mainstream interpretations of electrical origin.

Specifically, one might be able to check sedimentary deposit outside the crater versus inside for clues as to origin. The electrical theory (as I understand it) would expect a layering of sediments outside the larger crater OPPOSITE of layering inside the larger crater (the sedimentary layers for comparison being those seen in the larger crater's walls). Of course we'd need to actually excavate surrounding areas and compare to the crater itself. So, that may not be possible for some time.

The theory goes that braided/rotating electrical arcs slowly, or likely relatively quickly, machined material out of the crater(s) layer by layer. If that's the case, we'd expect to see a relatively fine anti-layering or opposite layering outside as in the walls of the crater. IE, what would have been the top layer of the material formerly in the crater, would form the bottom layer of deposition elsewhere outside.

That would also be a bit different from the volcanic or impact model. Impact wouldn't really expect layering, but mixed sediment/ejecta. Volcanism might expect layering but not in a manner directly opposite layering inside the crater.

As to the smaller crater, there probably wouldn't be enough material ejected to really do a definitive analysis. But if we looked at the larger crater and its ejecta, it might give clues to the smaller crater too. If we could get a look at the smaller crater, take samples, and look at its composition, and how the crater itself is structured... Could be interesting.

Anyway, it doesn't look especially volcanic from photos so far aside from passing resemblance... I suppose it bears superficial resemblance. However, we also know that electrical arcing preferentially strikes toward higher ground, taller objects, and along the ridges of craters, mountains, etc. So, it's just as plausible to say it's an electrical blister

(http://www.thunderbolts.info/tpod/2004/arch/040705olympus-mons.htm
http://www.thunderbolts.info/tpod/2004/arch/040702craters.htm
http://www.thunderbolts.info/tpod/2005/arch05/050329domedcraters.htm
http://www.thunderbolts.info/tpod/2005/arch05/050608craters.htm
http://www.thunderbolts.info/tpod/2004/arch/041102layered-crater.htm)

from a large electrical arc/lightning strike, which can easily be mistaken for a volcanic or impact crater. Morphology alone can support several different interpretations. In the electrical interpretation, we know from experiments that there are often secondary or tertiary strikes in the same area as the main strike. And after the initial formative events create a crater, electrical arcs may preferentially strike along the rim. So, a large crater with smaller or micro-craters along the rim is a relatively expected feature in an electrical hypothesis, based on observations of how electricity acts on Earth and in the lab.

I think more investigations are needed on any/all theories before ANY one theory can be definitively picked as a winner. But that's the fun of scientific exploration, trying to figure out from the data what's actually going on. My 2c.