Unsettled Earth

I love the west coast even though anyone with eyes can see it's a dangerous place. It's so mountainous! True, mountains are beautiful. But they are the remnants of violence.

If the face of a mountain is partly striped, as many of them are, you understand that the striping represents layers of sediment, layers of earth that accumulated downstream from somewhere else or settled at the bottom of the sea, then were buried by other layers until the weight was such that the lower layers became rock, way down under the surface of the ocean, or below many additional layers of the earth.

But remember: We're looking at a mountain. The striping is up there, not below our feet. How did it get up there? Not gently. Sediment rose from far below sea level to thousands of feet in the air through a succession of violent movements by seismic and volcanic forces powerful enough to literally rip apart the surface of the earth.

To see it happen, to perceive the violent power of the Pacific Coast's churning geological engine, you'd have to live tens of thousands of lifetimes. Except once in a while, it accelerates, so we can watch. Like now, on Mount St. Helens in Washington:

USGS Mt St Helens slab.jpg

According to this AP story:

If the skies are clear as forecast, volcano watchers who turn out for the reopening of the Johnston Ridge Observatory on Friday will get a spectacular view of a hulking slab of rock that's rapidly growing in Mount St. Helens' crater.

It's jutting up from one of seven lobes of fresh volcanic rock that have been pushing their way through the surface of the crater since October 2004.

The fin-shaped mass is about 300 feet tall and growing 4 feet to 5 feet a day, though it occasionally loses height from rockfalls off its tip, said Dan Dzurisin, a geologist at the U.S. Geological Survey.

It began growing last November, steadily moving west and pushing rock and other debris out of its way as it goes.

Mount St. Helens has been quietly erupting since a flurry of tiny earthquakes began in late September 2004. Scientists initially mistook the quakes as rainwater seeping into the hot interior of the older lava dome.

But it soon became clear that magma was on the move, confirmed by the emergence of fire-red lava between the old lava dome and the south crater rim a few weeks after the seismic activity began.

The volcano has continued pumping out lava ever since. Eventually, scientists expect the volcano will rebuild its conical peak that was obliterated in the May 18, 1980, eruption that killed 57 people.

The current growth of the new lava dome has been accompanied by low seismicity rates, low emissions of steam and volcanic gases and minor production of ash, the USGS said.

"Given the way things are going now, there's no hint of any sort of catastrophic eruptions," USGS geologist Tom Pierson said. "At any time, however, things can change."

"Any time" defined as from tomorrow morning until 10,000 years from now. A blip, in terms of the age of the Earth.

(P.S. I know, I know, I read the papers, I know what I'm supposed to be worrying about right now. News like this helps put my problems in perspective.)


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