Cascadia Subduction Zoneedit this page
From Seattle Wiki
The Cascadia Subduction Zone is a giant fault running off the coast of the Pacific Northwest. It is where the Juan de Fuca plate slides under the North American plate. When stress builds up between the plates an earthquake goes off sometimes accompanied by tsunamis. It's one of the biggest dangers towards Seattle. The last time it went off was in 1700.
[edit] Potential Hazard to Seattle
The Cascadia Subduction Zone is in close enough range (how far?) to Seattle to cause serious damage (requires magnitude or number) to the city. It would be "the big one" we all anticipate. A Cascadia Subduction Zone earthquake would be around 9.0 magnitude (what does "around" imply about the uncertainty?). The shaking would be so strong that you would barely or not be able to stand in it for an eternity of about four minutes (awkward use of infinites).
Brick buildings would certainly collapse (evidence?). So areas like Pioneer Square would be obliterated. Even with retrofits, brick constructions will still be severely damaged (because bricks move back and forth). Suburban housing (houses) with wooden frames could (may) be less damaged if anchored to their foundations (figure required to demonstrate this principle).
Seattle also has a lot of area built on fill (which area?). In an earthquake, fill turns to liquid and structures on it can't be supported (how do we know this?) ,so they (what kind) collapse as their foundations sink into the ground (all the way under?). Qwest Field, Safeco Field, Harbor Island, the waterfront, and the industrial district are all built on landfill. These areas will be the most damaged. However, Safeco Field was built on pylons which were drilled into bedrock (not sitting on fill) and will be relatively unaffected by an earthquake.
Experts debate what would happen to downtown's skyscrapers. In a normal quake they are some of the safest areas, but a Cascadia quake would be much stronger (how much?). Some argue they (people?) could not handle so much shaking and would collapse. Others say some should remain standing (is this an opinion?). Even if they can stand, the debris from all of their (who? what?) damage like glass or other building material could bury the streets along with pedestrians and automobiles . (What is being done to minimize this risk to pedestrians and automobiles?)
Other structures at risk include highways and bridges. Notably the Alaskan Way Viaduct which is already at plan to be replaced due to earthquake risk. (this is not a sentence)
Tsunamis would not pose a risk to Seattle because Puget Sound is protected by the Olympic Peninsula. (What about the Olympic Peninsula decreases the risk to Seattle?)
It would still be the worst disaster Seattle has ever experienced. (Figure comparing predicted damange to past disaster would make this more clear)
The threat is not very well known (how do we know this? Figure, chart, statistics?). So if you are visiting or living in Seattle, be prepared and remember that you are in giant earthquake country (giant is not a number, is Seattle know by this phrase?)(whoever wrote all the parenthesis is a tad obnoxious).
