Skip to comments.Vanity: Question about Seismic activity
Posted on 10/01/2007 5:22:14 PM PDT by Blogger
Posted this question on another thread but had very little response. As I look at the ring of fire right now, there is a massive amount of activity, BIG activity in the Pacific ocean towards Asia. There is also a lot of activity in South America and a little in Central America. The only thing on my chart on the west coast that registered at 4.0 or above was a small quake in Oregon.
Question is, with all of these plates shifting, and the plates around our nation's plates staying pretty quiet, what is this doing to our risks of a massive release? The answer I received was that maybe a lot of these smaller ones are enough to relieve the pressure build up. Any seismologists or other earthquake experts out there?
No one knows. There is not enough historical data to empirically answer your query
My understanding is there is always “massive” activity on the ring of fire, that just goes with the subduction. The plates that form the two sides of the San Andreas fault are moving lateral to each other, not one under the other like most of the ring of fire. The San Andreas blows off a big quake every 150 years or so. The last big one along the SA fault in Northern California was the 06 San Francisco quake, and in Southern California it was the 1857 Fort Tejon quake.
California is due for a big one on the SA, regardless of what is going on around the Pacific.
Maybe the Three Gorges Dam is at fault. ;-D
I would not want to be in Memphis if the New Madrid fault has a happy day
I’m not an expert but I’ve been watching quakes online for about 8 years. It usually is more active on the eastern side of the Pacific. I don’t know why. Just something I’ve observed over the years. However, looking at that map, it does seem unusually quiet over here on the Western-Hesmisphere-side of the ring of fire. Especially Alaska. I don’t know what that means, either. Hope I helped. :)
“I would not want to be in Memphis if the New Madrid fault has a happy day”
I’m not sure I’d want to be ANYWHERE in Southwest Missouri if New Madrid cuts loose, much less Memphis.
Firstly, I am not a seismologist. However, I do have an opinion.
I think there is very little correlation to what is happening on the other side of the world. The scale is too immense.
The theory of stress release does work on a local level though.
It seems that the scale(richter) scale of these earthquakes is huge. Quite a few 7s or higher. Seems unusual, but I could be wrong.
Very interesting about 1857 Fort Tejon quake.
New Madrid is interesting. I’ve been watching that one a while and it is pretty quiet for something that blew so big in 1811.
Of course, there is the seismicity of Yosemite as well. But these are things that we don’t think of so much when we think American earthquakes. We tend to think West Coast. And it has been oddly quiet.
I’m about 70 miles NW of New Madrid. All of my immediate family lives somewhere along the New Madrid fault.
Once you start looking at that stuff daily for years you realize it pretty much always looks like that.
I've noticed when people START looking at global seismic maps they really astonished at the level of activity. Also there's greater news coverage of worldwide quakes.
Not nearly as much as people think. Each whole number of magnitude is about 32 times more energy release.
The overwhelming majority of worldwide seismic stress is released in massive earthquakes. All the little quakes DON'T really add up.
For example, in Southern California it would take over 30,000 magnitude 4 quakes to release the same stress as a damaging magnitude 7 quake. So while people may comfort themselves when a 4.0 occurs there that "at least it's releasing stress" really it's irrelevant.
even the 7 & 8 pointers?
There have been 12 Mag 7+ quakes worldwide this year; in an average year, there are 18 such quakes. So, actually, we're a hair BELOW average in the number of such quakes.
However, there is on average 1 Mag 8+ quake a year, and we've had 3 already, so that number is above average. It's not a record for the number of such quakes.
There was an interesting article in a scientific journal a few years ago that showed some tentative evidence that there were decadal-scale cycles in subduction quakes vs. large strike-slip quakes (like the San Andreas)- almost all the 8+ quakes are subduction ones so you'd ger more of the REALLY big quakes in the subduction cycles, which we'd appear to be in now, if such a thing does exist.
There's certainly been no statistically glaring increase in large quakes, though.
To assume that stress must constantly build to the point where the result is a major quake seems erroneous. There are periods of time where continental plates slide along or under other plates more easily.
My geology professor used the analogy of a large bowl of oatmeal. As it cools, it hardens on top. Inside the bowl the oatmeal is still boiling and sending up the large bubbles of magma which propel the solid surfaces in different directions.
Given the size of our bowl of oatmeal, we often cannot visualize/predict tectonics on a world scale.
If this response wasn’t corny enuf, make yourself a pan of oatmeal. Then sit and observe the cooling oatmeal. If you want, you can even float some solids on the oatmeal to observe how they interact with each other as the food cools.
Sheesh, now I’m hungry. Off to the kitchen for............a bowl of oatmeal.
Merciless criticism from FRepers expected.
I felt an earthquake in the Pacific Northwest
this morning at 6:16am, but can’t find a
report. Is there a site that paralels the
international time zones? I’d like to see
if there was an earthquake somewhere in the
world at that time.
Are you certain that it wasn't merely the death rattle of Seattle's soul as it collapses under the vile weight of the Marxist leviathan?
I assume that you've tried at least a couple of different search engines with obvious keyword phrases such as "earthquake October 2007" "washington earthquake" "washington seismic activity" etc. etc
The U of W has a seismic lab with the traditional scrolling papers and wiggling pens that the hair-in-a-can 'journalists' rush to at the slightest tremor....they would probably know :-)
I followed all the links on Drudge’s Quake Sheet.
Nothing but a quake in Seattle this afternoon in
registering the low 3’s. Nothing at 6:16am.
I’ve been looking for you too Jo. I saw one seismograph that had a minor blip around that time (if I’m reading correctly). You haven’t had any weird ear sounds or headaches today have you?
Here’s one of the seismographs with a blip
This page may also possibly be of interest
If that page doesn't give you the information that you want, you should harass the people at the U of W here....... be sure to adopt a belligerent demeanor if you call:
Earth and Space Sciences
(Geology, Geophysics, Geological Sciences)
University of Washington
Johnson Hall 070 Box 351310
4000 15th Avenue NE Seattle, WA 98195-1310
Phone 206-543-1190 Fax 206-543-0489
He’s pretty conservative on such things but he should give you a knowledgeable answer.
There is no ‘norm’ to measure it by.
My my. You are definitely on the
top of your snark tonight. Love it!
The answer is no, they are not enough to prevent a massive, large event from occurring.
Your question has been described as being the difference between a “minute of terror” and a “decade of fear”. Studies in the Pacific Northwest have pretty much proven the “minute of terror” part. They went out to deep offshore oceanic chasms and took core samples from the bottom. Quakes show up in the samples because there is always a signature “falling” of sediment from up above when a moderate to large quake happens.
These studies helped pinpoint the last great seismic event in the Pacific Northwest/Cascade zone, IIRC a Magnitude 9+ that happened Jan 20, 1699, that disrupted 1,000 miles of the Pacific Coast and sent a tsunami to Japan that they still have preserved written records about.
So the “small ones” are not really relieving tension, they are an effect, as huge blocks of rock are cracked and crumbled and crushed. It could even be argued that the small ones cause the plates to become more interlocked, thus increasing the likelihood that a large one will happen, albeit possibly further out on the time scale.
Sadly, no number of “small ones” will stop the plates. But neither will the “big ones”.
Stategerist and I have already met and he was quite helpful.
Glad to read of it.
Thanks for your kind note.
Why thank you for your kind words :-)
Here's a nice piece of cheesecake for you.
I was thinking more on the order of 6+ for any significant stress relief.
Even then, it is an extremely inexact science and probably will remain so for my lifetime.
It’s Darksheare’s fault.
I thought that was a given..?
Just noticed your post inferring that I had
experienced a phantom earthquake due to sensory
instability caused by a headache.
Come to think of it, I did have an extra helping
of Just Lori cake left over from the Puget Sound
Freeper party AND I finished the “Congratulations”
What? Couldn’t let a good cake go to waste.
<<< applauding Jo Nuvark’s dedication to avoiding waste as well as her attention to proper nutrition, particularly when it involves Essential Food Items such as cake. I seem to recall Cake as having a particularly prominent position in the Food Pyramid, right alongside Ice Cream, Steak and “An Occasional Whisky”.
Gotta be real careful with Just Lori’s “geocake”!
I remember the big one we had here in 2000/2001 (?) I was online FReeping and there was a long rolling quake that went on forever. Somehow it never occurred to me to get out of the house, or go under the metal desk where I was sitting. Rather, I stood up and grabbed both computer monitors so they would not fall and get damaged... I laugh every time I think about it. All my early childhood training apparently GONE!
Of course, as an adult I know how to prioritize what's important! ;) I can say proudly that as soon as I could stand up straight I posted the BREAKING NEWS about our PNW earthquake! Yes, the COUNTRY knew because of me :)
Everybody in our building ran OUTSIDE where it was SAFE... under all those power lines on the tide flats. Getting across the parking lot reminded me of all the times I’d been on a train .... trying to get to the dining car.
FWIW you might try watching the Lost & Found ads for Dogs/Cats&Birds. There SEEMS to be loose correlation between rise in pets running away and earthquakes. The more pets gone the higher the magnitude. This is after ruling out other factors like 4th of July or heavy storms. The 89â Loma Prieta quake had a surge of pets running away about a month prior. Also there were at least 2 beachings of either dolphins or some sort of a rare whale
[...Cake has a particularly prominent position
in the Food Pyramid, right alongside Ice Cream,
Steak and An Occasional Whisky”...]
Darn right! It’s called the Hypo Glycemic
Exchange Diet. Anything sweet. Chocolate is
essential. Wait... did you say “Snicker”?
Now you’ve done it.