The geological phenomenon that creates islands like the Hawaiian Islands is called hotspot volcanism. This occurs when a plume of molten rock rises from deep within the Earth's mantle and penetrates the crust, leading to volcanic activity. Over time, as tectonic plates move, the volcano may become dormant, creating a chain of islands. The Hawaiian Islands were formed through this process, resulting in a rich volcanic landscape and diverse ecosystems. This unique geological activity contributes to the islands' beauty and biodiversity, making them a fascinating study area for scientists.