Waimea Canyon travel guide

Waimea Canyon is a large canyon, approximately ten miles (16 km) long and up to 3,000 feet (900 m) deep, located on the western side of Kaua i in the Hawaiian Islands. Dubbed the "Grand Canyon of the Pacific" by Mark Twain, the canyon was formed by a deep incision of the Waimea River arising from the extreme rainfall on the island's central peak, Mount Wai ale ale, among the wettest places on earth.
Geologically the canyon is carved into the tholeiitic and post-shield alkalic lavas of the canyon basalt. The lavas of the canyon provide evidence for massive faulting and collapse in the early history of the island. The west side of the canyon is all thin, west-dipping lavas of the Napali Member, while the east side is very thick, flat-lying lavas of the Olokele and Makaweli Members. The two sides are separated by an enormous fault along which a large part of the island moved downwards in a big collapse.
The canyon has a unique geologic history—it was formed not only by the steady process of erosion, but also by a catastrophic collapse of the volcano that created Kaua i.
Like the other Hawaiian islands, Kaua i is the top of an enormous volcano rising from the ocean floor. With lava flows dated to about 5 million years ago, Kaua i is the oldest of the large Hawaiian islands. Roughly 4 million years ago, while Kaua i was still erupting almost continuously, a portion of the island collapsed. This collapse formed a depression, which then filled with lava flows. (...) more....