Some overall pictures would be good. And overall of the pool. Is the coping good all around?
Those look like typical expansion contraction cracks in unreinforced concrete. But because I'm not there and we don't have more pictures, that's more of a guess.
All concrete cracks, the goal is to control cracks. Pools crack less because they are very high strength cement over a intense rebar cage, the water inside tends to moderate temperature changes.. Decks crack more because they are usually poorly reinforced thin structures that move all over the place as temperature changes. That is what is probably happening here. But without a site visit one can't really be certain. I know a couple concrete guys in Sacramento but regrettably none where you are.
