Historic Resource Study, Crater Lake National Park, Oregon, 1984
V. Geological and Biological Information on Crater Lake Area
D. Volcanic Parks
1. Importance in National Park System
Mounts Garibaldi, Baker, Glacier Peak, Rainier, St. Helens, Adams, Hood, Jefferson, Three Sisters, Mazama, Shasta, and Lassen Peak all are part of a long string of volcanoes stretching in a broad arc from South America north and west toward Alaska, Japan, and Indonesia. Referred to with respect as the “Ring of Fire” because of its frequent and dramatic eruptions, this chain includes about seventy-five percent of the world’s 1,300 active volcanoes. In the Cascade Range, the high peaks we admire today have all been active for the last million years at least, with Mounts Baker and Rainier in Washington and Hood in Oregon all restless even into the nineteenth century. In the twentieth century, Lassen Peak was the center of attention on this continent from about 1914 to 1921 as it periodically expelled steam, volcanic rock fragments, and lava. Even its violence, however, has been immensely overshadowed by the spectacular self-destructive explosion of Mount St. Helens on May 18, 1980. All this activity tends to suggest that the Cascade Range is not volcanically dead, but only dormant, thereby making it one of the best areas in which to observe volcanic movements today. Four of the National Park Service’s volcanic parks–Lassen Volcanic NP, Mount Rainier NP, Crater Lake NP, and Lava Beds NM–are connected with the Cascade chain. Oregon itself has a wider variety of volcanic rock than any other state, and its variety of volcanism and long period of activity is unexcelled even by Hawaii.