Mt. Rainier, USA.

21/06/2011

 
Mount Rainier is a glacial covered stratovolcano situated on the western seaboard of the USA. It is the highest of the peaks at 4392 m in the Cascade Range and my personal favourite of the Decade volcanoes.
Picture
Taken by Lyn Topinka, Rainier with Tacoma in the foreground.
With its towering position over the cities of Seattle and Tacoma it is seen a great hazard of the future, particularly with threat of lahars because of the large amounts of ice, and snow on its flanks and summit. This is the major reason for its inclusion as a Decade Volcano. However there are other hazards, in the past debris avalanches caused by the collapse of part of the edifice have travelled very long distances and can reach as far as the Puget Sound. An event such as this occurred around 5600 years ago in a similar but larger event to that which occurred at St. Helens in 1980. Of course a large eruption of Rainier would also be accompanied by the usual ensuing volcanic hazards (Pyroclastic Density Currents, Ashfall, Lava flows).

The main edifice is around 500,000 years old and is composed of mostly lavas which have built up over time.  It is unclear when Rainier last event minor event was with different souces stating different things! According to the GVP an event occurred back in 1894 which involved minor activity at the summit. It has been a while since any major activity has been seen, with up to VEI 4 events occuring in the past as is shown on the GVP. With a volcano such as Rainier any future eruption it is highly probable that it would be preceeded by warning signs such as deformation, hydrothermal activity and degassing increases. Despite the location of Rainier, there is a lot more work to be done on the volcano to understand its history and hence its potential future!

Picture
Rainier as taken from the space needle on a very hazy day!

I am afraid that posts will be a little more sparse and irregular over the coming months due to an extremely busy summer (getting married and a dissertation to complete!), however I should get back to regular posting by the end of July!

Sources
USGS
Global Volcanism Program
Sisson, T.W., 1995. History and Hazards of Mount Rainier, Washington. USGS. Open-File Report 95-642.
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