That's the theme I presented here. I came up with a bunch of possible causes for underground fire, some far fetched, some contradictory. You don't need to poke holes in that point by point. However, I believe this main idea has merit, and can explain how widespread these deluvial features are. While there are surely weaknesses in this theory, and I don't proclaim that it explains all the deluges, the other theories seem to have weaknesses too. Perhaps all these mechanisms, volcanism, cratering, and underground fire caused deluges at some points in time. I think that underground fires on a planet much richer in Sulfur (Nitrate too?) than Earth, could have had a substantial role in the evolution of the atmosphere. Even on Earth, underground fires have played such a role, though the evidence for widespread cataclysms, if they occurred, has been destroyed by tectonism and time. Perhaps Mars "petrified" at a stage where this evidence is still preserved. Deposits such as Rio Tinto do catch on fire.