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November 22, 2013
(20 Sept. 2012) --- Mount Shasta, California is featured in this image photographed by an Expedition 33 crew member on the International Space Station. The Cascade Range includes many impressive stratovolcanoes along its north-south extent, some active over the past few hundred years. Mount Shasta in northern California is among the largest and most active (over the past 4,000 years) of the volcanoes in the Cascades. The summit peak of the volcanic structure is at an elevation of 4,317 meters above sea level, and is formed by the Hotlum cone -- the location of the most recently recorded (1786) volcanic activity. The summit is high enough to retain snow cover throughout the year, and several small glaciers are present along the upper slopes of Shasta. Immediately to the west of the summit peak, but still on the upper slopes of Shasta, is the Shastina lava dome complex, reaching 3,758 meters above sea level. Two dark lava flows that originated from the Shastina complex and flowed downslope (toward the northwest) are visible in the lower part of this image. These contrast sharply with the surrounding vegetated (green) lower slopes and the barren upper slopes (gray) of Shasta. The Black Butte lava dome complex forms another, isolated hill on the lowermost slopes of Shasta near the town of Weed, CA (right). Geologists have mapped prehistoric pyroclastic flow and mudflow (also known as lahars) deposits from Hotlum cone and the Shastina and Black Butte lava dome complexes to distances of 20 kilometers from the summit of Shasta. As Mount Shasta has erupted within the past 250 years and several communities are within this hazard radius, the United States Geological Survey's California Volcano Observatory actively monitors the volcano for signs of activity.