Iliamna Volcano

About Iliamna Volcano:

• It is located in southwest Alaska, United States.
• It sits in the Chigmit Mountains within Lake Clark National Park and Preserve.
• It soars to 10,016 feet (3,053 m) tall from nearby Cook Inlet.
• Iliamna is a stratovolcano, characterised by its steep, conical shape and periodic explosive eruptions.
• It comprises andesite lava flows and pyroclastic rocks on a base of Jurassic-era granite.
• The volcano is not a symmetric cone but is made of a summit peak and four other peaks that make a 5-km-long ridge.
• Most of the volcano is covered by perennial snow and ice, and numerous glaciers radiate from the summit area.
• Large avalanche deposits occur on the flanks of the volcano, particularly down the Umbrella Glacier on the southwest side of the volcano.
• The volcano is currently considered dormant, as the most recent reported eruption occurred in 1876. 

What is a Stratovolcano?

• It is a tall, steep, and cone-shaped type of volcano.
• Unlike flat shield volcanoes, they have higher peaks.
• They are typically found above subduction zones, and they are often part of large volcanically active regions, such as the Ring of Fire that frames much of the Pacific Ocean.
• Stratovolcanoes comprise the largest percentage (~60%) of the Earth’s individual volcanoes, and most are characterized by eruptions of andesite and dacite, lavas that are cooler and more viscous than basalt.
• These more viscous lavas allow gas pressures to build up to high levels. Therefore, these volcanoes often suffer explosive eruptions.
• They are usually about half-half lava and pyroclastic material, and the layering of these products gives them their other common name of composite volcanoes.
• At the peak, stratovolcanoes usually have a small crater. The crater may be filled with water or ice, or it may contain a volcanic dome during a period of relative inactivity.