Kısaca
Volcanic eruptions were Hephaestus"s forge, earthquakes were Poseidon"s rage. Every natural event had a god.
In Ancient Greece, natural events were the work of gods. Lightning storms were weapons thrown by Zeus, king of gods, at his enemies.
When Zeus got angry in his throne on Mount Olympus, the sky darkened and lightning struck. Volcanic eruptions came from Hephaestus"s underground forge. Earthquakes were Poseidon striking the ground with his trident.
This belief system gave people a way to explain the world. In pre-scientific times, mythology was essential for making sense of seemingly random events.
Source: Classical Mythology Studies