Chaos Crags

Over the last 3 million years, regional volcanism in the Lassen segment of the Cascade arc constructed a broad platform of volcanic rocks. In periods of about 50,000 - 200,000 years, concentrated volcanism occurred in localized areas. These "volcanic centers" are defined as large, long-lived edifices erupting the full range of lava compositions from basalt to rhyolite.

Chaos Crags, located northwest of Lassen Peak, erupted 1,100 years ago and is the youngest unit of the Eagle Peak sequence.