Thursday, February 9, 2017

Todays Highlights

Volcanoes and the Cascadia Subduction Zone

I have long wondered about the relationship between the colliding plates and when "Old Shakey" arrives, how it will affect our volcanoes.

In this image you can see how the San Juan de Fuca plate grinds down under the North American plate. When it reaches a certain level, it begins to heat up and liquify. Which is why we have volcanoes in the areas that we do.

According to Wiki:
The Juan de Fuca plate moves toward, and eventually is shoved beneath, the continent (North American plate).  Here, the oceanic crust of the Pacific Ocean has been sinking beneath the continent for about 200 million years, and currently does so at a rate of approximately 40 mm/yr.
At depths shallower than 30 km (19 mi) or so, the CSZ (Cascadia Subduction Zone) is locked by friction while strain slowly builds up as the subduction forces act, until the fault's frictional strength is exceeded and the rocks slip past each other along the fault in a megathrust earthquake. Below 30 km (19 mi) the plate interface exhibits episodic tremor and slip.
The width of the Cascadia subduction zone varies along its length, depending on the angle of the subducted oceanic plate, which heats up as it is pushed deeper beneath the continent. As it becomes hotter and more molten, it eventually loses the ability to store mechanical stress and generate earthquakes

So my question was: will "Old Shakey" suddenly waken our sleeping volcanoes again?
KTVZ had a timely and interesting special report on the subject here.

You can also get associated seismic updates here, at the Cascades Volcano Observatory.

And in other news:


This is what my month has felt like

I leave you with this final thought for the day:
As I ponder things and people it occurred to me that when we become obsessed with the utter destruction of a thing/idea/person/company we hate, far too often we end up becoming a carbon copy of that thing we hate.

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