Alaska Volcano Observatory

Looking south at the southern caldera rim from above Turquoise Cone. This prominent portion of the southern caldera wall represents a pre-caldera stratocone that was almost entirely destroyed in the caldera-forming eruption 9,400 years ago. The stream in the middle ground drains the southern half of the caldera, flowing southwest (right) through the southern outflow canyon, a 100-m deep, 500-m wide break in the caldera wall.