Decade Volcanoes (and Mount Rainier in particular)

By Jack Brummet, Seattle Metro Editor

The Decade Volcanoes are sixteen volcanoes "identified by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) as being worthy of particular study in light of their history of large, destructive eruptions and proximity to populated areas."  I live fifty miles from one of them.

click to enlarge - licensed from Wikipedia Commons

According to the Wikipedia, "Mount Rainier is a massive stratovolcano located 54 miles (87 km) southeast of Seattle in the state of Washington, United States. It is the most topographically prominent mountain in the contiguous United States and the Cascade Volcanic Arc, with a summit elevation of 14,411 feet.  Mt. Rainier is considered one of the most dangerous volcanoes in the world because of its large amount of glacial ice."

The three summits of Mount Rainier

In an eruption, Mt. Rainier could produce massive lahars that would threaten the whole Puyallup River Valley.  A lahar is a mudflow or debris flow composed of a slurry of lave, rocky debris, mud, and water. 

Hazard Map showing potential mud and lava flows

The U.S. Geological Survey says that "150,000 people live on top of old lahar deposits of Rainier. Not only is there much ice atop the volcano, the volcano is also slowly being weakened by hydrothermal activity. According to Geoff Clayton, a geologist with a Washington State Geology firm, RH2 Engineering, a repeat of the Osceola mudflow would destroy Enumclaw, Orting, Kent, Auburn, Puyallup, Sumner and all of Renton.  Such a mudflow might also reach down the Duwamish estuary and destroy parts of downtown Seattle, and cause tsunamis in Puget Sound and Lake Washington."

IAVCEI's list of the 16 decade volcanoes:


Avachinsky-Koryaksky, Kamchatka, Russia
Colima, Jalisco and Colima, Mexico
Mount Etna, Sicily, Italy
Galeras, Nariño, Colombia
Mauna Loa, Hawaii, USA
Mount Merapi, Central Java, Indonesia
Mount Nyiragongo, Democratic Republic of Congo
Mount Rainier, Washington, USA
Sakurajima, Kagoshima Prefecture, Japan
Santa Maria/Santiaguito, Guatemala
Santorini, Cyclades, Greece
Taal Volcano, Batangas, Luzon, Philippines
Teide, Canary Islands, Spain
Ulawun, New Britain, Papua New Guinea
Mount Unzen, Nagasaki Prefecture, Japan
Vesuvius, Naples, Italy

Mount Rainier in 1895

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