Hephaistos (heh-FAIS-toss) is the blacksmith god, the god of volcanoes and hot fires and smelting metal ore to make iron. People said he lived inside volcanoes, and when they erupted it
was because Hephaistos was moving around.
Hephaistos was Hera's son, and was not thought of as having had any father. People said that Zeus had thrown him off Mount Olympus down to earth, and he had injured his legs in his fall and couldn't walk well.
This story shows his connection to the earth in several ways: Hera, Gaia's daughter, is an earth goddess, and her son is also earthy. He is thrown from Mount Olympus down to the earth, and he crawls on the earth instead of walking with his head high like a sky god. Of course the god of volcanoes would have to be an earth god and not a sky god, because volcanoes are inside the earth.
In some stories, Hephaistos is married to Aphrodite, but they never seem to get along very well. She likes Ares better.
To find out more about Hephaistos, check out these books from Amazon or from your local library:
D'aulaire's Book of Greek Myths, by Edgar and Ingri D'Aulaire.
Greek Religion, by Walter Burkert (reprinted 1987). By a leading expert, for adults. He has sections on each of the Greek gods, and discusses their deeper meanings, and their function in Greek society.