NW coast accel.uplift?
9 messages in this thread
How long has accel. been in progress? Is rate of accel. increasing? Any
volcanic activity studies showing unusual rates of change ECT. I
notice an increase in the media on the disaster prepardness aspect
currently. Any thoughts or observations?
Hi, Paul–
Welcome to the forum/section!
I have not heard of an accelerating uplift in the Pacific Northwest; but I am
no expert and perhaps someone else here will have more to say on that.
Any increases in disaster preparedness may have more to do with increased
awareness of earthquake possibilities based on recent determinations of
prehistorical quake sizes and dates in the area, which I have heard about.
Also, things like Mt. St. Helens tend to provoke some such activities whether
or not they are part of such a pattern.
–Doug
Paul and Doug
I saw the news that reported increased uplift in the PNW, but not much data was
given. Again tonight there was a report that earthquake and volcanic activity
has increased but there was no time table given. I am curious as to if it has
increased in the last 20 years but may still be much less than any other
increase of 40 or 80 or xx years ago and thus is just a normal cycle change,
and perhaps might even still be less than 40 or 100 years ago.
It would be nice if we could actually get enough info off the TV to actually
learn something.
Lanny
In the January 1993 issue of _Earth_ magazine is an article abou the
Olympic-Wallowa Lineamant, which I think is part of what you're talking about.
We have enough faults down here in So. Cal., so I haven't been keeping up with
the NW ones. Earth is published by Kalmback Pub. (800)533-6644. It's a good
general interest geologyish magazine, published by the publishers of
_Astronomy_.
Firstly I apologise for the second message under new subject header on same
subject,but it appeared the first message vanished.I'm still learning to
navigate the system.
From what I understand,there isn't much seismic activity in the Pac.NW but
when quakes do occur they can be in the mag.8+ range.With so little activity in
the area I don't beleive they have any real construction codes such as Ca. has
implemented.Having experienced the 9.2 mag. quake in Anchorage in 1964 I can
understand the concern people may have in that area.This should be interesting
to watch.
Paul
This is still part of "The Ring of Fire", don't look for a constant predictable
rate of change. Rather such activities tend to be intermittent and dramatic in
the changes they bring.
Doug.. Paul must have seen the news report on some Univ. of Oregon geologists
who have been measuring NW coast uplift, and are predicting a major (9 richter)
quake in the not distant future. I am relying on memory, but it seems to me
the Juan de Fuca plate is plunging downward under the North American plate at
an accelerated rate. There is not a whole lot left of this plate, so I
visualize a sort of final gulp as it plops into the mantle.
— Bill
Hi, Bill–
A final gulp seems reasonable if plates are pulled down by the subducted parts
of the plate – when there is little left at the surface, there would seem to be
less drag to resist the pull. This seems to getting us into the battle zone
between those who figure on such a subduction pull and those who figure push
from spreading zones is the main force.
–Doug
Doug.. It's the friction … smaller interface between the plate and the
underlying structures… which suggests to me that motion would be somewhat
accelerated when a plate was in the process of terminal subduction, whatever
the force (push or pull) that was causing it. Bill