It's easy to see how strange cultural taboos could get formed with this type of thing. Imagine a bunch of people in a tribe doing something on a beach (I don't know, eating crayfish or something). All of a sudden a huge explosion erupts on the horizon and the air is filled with a sulphuric stench. The medicine man/chief/authority figure says 'the gods are not pleased, we should not eat the crayfish'. They gather up all the crayfish and throw them back into the sea. The eruptions stop. Thus : the people stop eating crayfish for fear of upsetting their god.