Your child wants lava. They can say pyroclastic and they cannot say breakfast, and they want to know what happened at Pompeii, in detail, now. This is a shelf for that. Real eruption photographs, a cartoon bus in a volcano, a browsable reference to live in for years, and two novels about real disasters where real people died. Any one of them satisfies the whole thing. Two things to know before you pick. This subject is actually two subjects, volcanoes and earthquakes, and a child who loves one may not care about the other. And the last two books are a different animal entirely from the rest.
Start with the thing nobody tells you: this shelf is two subjects wearing one coat. Volcanoes and earthquakes come from the same cause, the plates of the Earth grinding against each other, so bookshops and school units file them together and this shelf inherited that. But your child may not have inherited it. A child who loves lava is often loving fire, color, and a mountain exploding, and has no interest whatsoever in plate tectonics. A child who loves earthquakes is usually loving something else, the idea that solid ground isn't solid. Find out which one you have before you spend money. The second thing worth knowing is what the pictures are made of, because for this obsession that is the entire difference. Seymour Simon and the DK Eyewitness and the National Geographic reader are real photographs of real eruptions, and that is what almost every volcano-obsessed child is actually after. The Magic School Bus is a cartoon, and it's the only funny book here and the only gentle one. Then there are the last two, and they are not fact books at all. They are novels, they are about real disasters, and people die in them. Reach for whichever one fits the child in front of you tonight.