Washington Roadcut and Mount Mazama Ash

September 20, 2018

Mount Mazama roadcut (1)

Photographer: Rebecca Roush 
Summary Author: Rebecca Roush 

Mount Mazama was a cluster of volcanoes in central Oregon that were destroyed during a series of ancient, massive eruptions. An eruption 7,700 years ago created a 30-mi (48 km) high column of pumice and ash. Note that the height of this column is estimated based on, among other factors, the volume and distribution of the ash deposits. Winds carried this ash across much of the Pacific Northwest, including to this roadcut on the North Cascades Highway, near Diablo Lake, Washington. The amount of ash distributed by Mount Mazama was over 40 times greater than the ash from the 1980 eruption of Mount St. Helens. Thus, the resulting ash layer that formed from Mazama's explosive eruption is sufficiently thick to be used as a geological time marker by geologists. Photo taken on June 22, 2018.

Photo Details: Camera: HTC 0PJA2; Exposure Time: 0.017s (1/60); Aperture: ƒ/2.2; ISO equivalent: 80; Focal Length: 4.7mm.