Geology of Katmai

Eroded bluff on the edge of the Valley of Ten Thousand Smokes

Ash in the Valley of Ten Thousand Smokes is now eroding into intricately carved badlands in many places.


Most people who visit Katmai fly to their destination. Above the land and water, people see a land pockmarked with ponds and lakes, cut with deep valleys, and rippled with glacial moraines—all of which is set next to the rugged spine of active volcanoes. Katmai National Monument was established in 1918 because of its geology. The stories of the rocks, volcanoes, fossils, and glaciers of Katmai reveal the formation of this landscape.
Fossils: Katmai contains many fossil bearing rocks.
Geologic Formations: What rock is underneath your feet? How old is it? Find out here.
Glaciers and Glacial Features: Glaciers have been and continue to be Katmai’s sculptor.
Valley of Ten Thousand Smokes: Unique on the face of the earth, this 40 square-mile area so enthralled early explorers that they lobbied for the creation of Katmai National Monument.
Volcanoes: Over one dozen active, and many more dormant, volcanoes lie within Katmai’s boundaries.

Did You Know?