reply to post by Lil Drummerboy
I do not spend a lot of time on ATS. I visit from time to time. I do have an interest in earthquakes since we have had swarms in Arkansas. But I don't
know anything about Oregon. I have never been there and I am not very familiar with earthquake activity there other than there are usually dots on
Oregon on the USGS website.
The dream struck a chord with me. Hopefully it was just some subconscious thing and not prophetic.
The seismic activity in the western United States is very, very interesting. It is also prone to severe disasters. If you look it up, you will find
stories from the past several centuries of 100 foot high tsunamis hitting the Oregon coast.
Here is why:
As depicted are the major fault lines running along the western United States. The major and obvious one is the San Andreas, which crosses through
California and then proceeds up off the coasts of Washington and Oregon. This is where the nonsense about California slipping into the ocean comes
from. Geologically speaking, if the North American plate were a subduction zone, and dipped under the Pacific plate, this would be possible. However,
almost all the time, the lighter Oceanic plate (Pacific) dips under the heavier, denser plate (North American plate).
HOWEVER, the San Andreas is a transverse fault line, meaning there is very little vertical change (Aside from mountains changing shape). Instead, in a
transverse fault line, the two plates glide, or more rather, grind against each other in a side by side motion. Generally, these types of earthquakes
are lesser magnitude than subduction zones, which brings us to the areas of Northern California (Far north) and the Oregon and Washington coasts.
As you can see in the diagram, there are several sub-faults to the North East of the San Andreas. The main one known as the Juan De Fuca plate (which
includes the Blanco fracture zone). Ever wonder why all those volcanoes from the tip of Northern California all the way to Canada are there? It is
because the Juan De Fuca plate is a SUBDUCTION zone. That part of the oceanic lithosphere, ever so often, dives under the North American plate. What
this does, is it not only injects magma under the North American plate, but also millions of tons of water. This caused these volcanoes to form.
Whenever there is a major earthquake on the Juan de Fuca, it not only has the potential to create massive tsunamis that are right off the coasts, but
the injection of lithospheric material and water create, well, imagine combining super hot silica (magma) and arctic cold water...big boom. This is
why these volcanoes erupt, most of the time.
Which brings us to today. There was recently a 6.9 near the lower edge of the Juan De Fuca, in fact right at the junction of the Mendocino fracture
zone and the beginning of the Juan de Fuca plate. This raises concern because if another were to hit there, it is possible that a local volcano that
has been known to be relatively active, could erupt. Ever seen Mt. Shasta erupt? That would be the most likely event, if additional earthquakes were
to take place, imho.
edit on 14-3-2014 by 1Providence1 because: (no reason given)