Why are there volcanoes here, what do they have in common and how do they differ?

In recent years, spectacular volcanic eruptions have repeatedly occurred on the Reykjanes Peninsula in Iceland and also on Kilauea in Hawai'i, attracting numerous tourists to the active volcanoes. The eruptions mainly produce lava and lava fountains, which is why they are classified as relatively harmless. The lecture will explain why volcanoes erupt in Iceland and Hawai'i, which, although quite similar, are fundamentally different in their plate tectonic classification. In other places, such as around the Pacific, completely different types of volcanoes are formed, which are often classified as very dangerous volcanic eruptions due to their extremely explosive activity. The difference to these volcanoes will also be explained in the lecture.