The Kauaʻi volcanoThe oldest main island
Kauaʻi is the oldest of the eight main Hawaiian islands, built by a single great shield volcano that rose from the sea about five million years ago. When the top of the shield collapsed it left a caldera 16 to 19 kilometres across, the largest in the Hawaiian Islands, which later filled with thick lava flows.
The main volcano went quiet around four million years ago, but small eruptions on the eastern side continued sporadically until about half a million years ago. Its highest summits, Kawaikini at 1,598 metres and Waiʻaleʻale beside it, catch so much rain, around 430 inches a year, that Waiʻaleʻale is one of the wettest places on Earth.
Waimea Canyon & Nā PaliWhat rain does to a volcano
All that rain has carved the old volcano into some of the most dramatic landscapes in the Pacific. Waimea Canyon, sometimes called the Grand Canyon of the Pacific, cuts through layers of lava that ponded in the old caldera, its red and green walls telling the story of eruption after eruption.
On the north and west coasts, waves and streams have shaped the knife-edge ridges of the Nā Pali Coast, which is reached on foot by the Kalalau Trail, or by boat and helicopter. Look closely at the cliffs and you can see the volcano's lava flows stacked like the pages of a book.
