Tuesday, July 15, 2014


Mt. Hood from the Portland, OR area
(Lynn D. Townsend)
I like living in the Pacific Northwest (PNW) and except for short stints in California and Texas during my time in the Army, I have lived here my whole life.

One thing you have to contend with living here is vulcanism.  That is: volcanoes.

Now we don't have hurricanes and we don't really get tornadoes (and if we do they are small and limited in damage).  But, especially on the coast, we have earthquakes and volcanoes.  Both are caused by plate tectonics, the movement of Earth's crust plates.  Here in the PNW we live with the results of the subduction of the Juan de Fuca plate under the North American Plate. (This is part of the "Ring of Fire" that surrounds the Pacific Ocean with volcanic activity.) This causes . . . volcanoes.  Now this is a eons long process and the Cascade Volcano Arc has been active for 37 million years.  But just 34 years ago, Mt. St. Helens erupted catastrophically with loss of life and a large amount of economic damage.

Living with volcanoes is a double-edge sword.  We have beautiful mountains and other geological features as a result.  Where I grew up in Southeast Idaho there were lava plains and Craters of the Moon National Monument.  We could see extinct volcanoes on the desert floor north of town.  When I moved to Washington State a few years before Mt. St. Helens erupted, I learned about columnar basalt and Mt. Rainier, the tallest volcano in the US outside of Alaska.  Then on May 18, 1980, Mt. St. Helens erupted and the resulting ash plume buried the town I lived in in nearly 6 inches of ash.  That after the ash blocked out the sun at 1:00 P.M. turning day into night.
Mt. Rainier from my deck. (S. Evan Townsend)

But still, I love volcanoes.  From my back deck I can, on a clear day, see two Cascade volcanoes: Mt. Rainier and  Glacier Peak.  Admittedly, I can only see the tops of them as they peek out from behind the other Cascade Mountains.  But still, I can see them.  With binoculars on a very clear day I have see volcanoes as far away as Mt. Hood in Oregon.

Because of PNW volcanoes, I can visit without too long of drives Yellowstone National Park, Crater Lake, the Columbia River Gorge (formed by fire and ice), and see pretty mountains whenever I drive west.

Now, there are worries.  Mt. Rainier is close to heavily populated areas such as Tacoma and Seattle and is overdue for an eruption.  It is being eaten from the inside by sulfuric acid and if part of it collapses without an eruption, it can send lahars into the populated Puyallup River Valley south of Seattle.  Even today you can see the evidence of lahars in Western Washington were valleys will have abnormally flat floors where a lahar "spackled in" the valley.

The beauty of the PSW is born of fire (volcanoes) and ice (ice age glaciers).  We love it.  But we have to be aware of its dangers.

1 comment:

  1. I love geology! Having a geophysicist father, I learned to appreciate both volcanoes and faultlines and the cool rock formations they create. It's dangerous, sure. But everywhere has their dangers. I'd rather live with earthquakes than tornadoes.