As part of Volcano Preparedness Month, DNR’s Division of Geology and Earth Resources has put together this fantastic profile on our most prominent volcano, Mount Rainier. Read through and learn how this peak that adorns our license plates and can be seen from the Peninsula to the Palouse has shaped our state’s breathtaking landscape.
Location: Pierce County, WA
Elevation: 4,392 m; 14,410 ft
Nearby towns: Orting, Seattle, Tacoma, Yakima
Mount Rainier produces andesitic and dacitic lava flows, pumice, and lahars.
The areas prone to lahars are determined in part by figuring out where lahars traveled in the past. Evidence of massive lahars is still abundant in many of the valleys that drain Mount Rainier. The figure at right shows the distribution of lava flows and lahars mapped at the surface compared to hazard zones (gray shaded areas). Much of the volcanic deposits have been either eroded or buried by rivers, glaciers, and human development.
ERUPTION AND LAHAR HISTORY
Modern Mount Rainier started erupting only 500,000 years ago with intermittent eruptions and mudflows thereafter.
Mount Rainier still issues steam and gases from fumaroles near the summit crater, which melt the snow and ice at the crater, as well as melt the summit icecap, forming caves…
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