Among the gases found in a fart are a composition of about 59 percent nitrogen, 21 percent hydrogen, 9 percent carbon dioxide, 7 percent methane and 4 percent oxygen. Only about one percent of a fart contains hydrogen sulfide gas and mercaptans, which contain sulfur, and the sulfur is what makes farts stink.
An explosion occurs when a large amount of energy is released into a small volume of area in a very short time. The energy released comes in many forms, including chemical (artificial explosives), nuclear and hydrothermal (volcano eruptions).
Burning very rapidly, explosive material releases concentrated gas that expands quickly to fill the surrounding air space and apply pressure to everything in it. That is, it explodes in a blast powerful enough to blow away nearby trees, cars, buildings and anything else in its path.