Plate tectonics
Discussion
Rather than bogging down the up to the minute discussion on Japan I thought I'd ask this here.
My understanding is that in the lead up to this quake there were a number of prior shocks that they only now can say were preshocks.
But can they determine that this the end of it or is it possible that an even bigger quake could occur over the next few days and this one get's downgraded to preshock?
Also any sensible discussion thoughts on whether astrological conditions do influence these in any way? Not from a direct cause, as we all know that this is just a release of built up pressure, but could it be the bit that provides the final trigger rather than waiting for just a pressure fault to occur, hence the coincedence?
And the tsunami itself, whilst dreadful, wasn't as high as I expected in my mind given the size of the quake. Had the epicentre been further offshore or in a deeper ocean trench would we have seen a much larger tsunami or conversely a much lesser one if occurring in shallower water.?
My understanding is that in the lead up to this quake there were a number of prior shocks that they only now can say were preshocks.
But can they determine that this the end of it or is it possible that an even bigger quake could occur over the next few days and this one get's downgraded to preshock?
Also any sensible discussion thoughts on whether astrological conditions do influence these in any way? Not from a direct cause, as we all know that this is just a release of built up pressure, but could it be the bit that provides the final trigger rather than waiting for just a pressure fault to occur, hence the coincedence?
And the tsunami itself, whilst dreadful, wasn't as high as I expected in my mind given the size of the quake. Had the epicentre been further offshore or in a deeper ocean trench would we have seen a much larger tsunami or conversely a much lesser one if occurring in shallower water.?
No real way at all to predict what's gonna happen in the future.
Have a look here to see all the recent earthquake activity around Japan: http://earthquake.usgs.gov/earthquakes/recenteqsww...
There's *A LOT*, by the way.
Have a look here to see all the recent earthquake activity around Japan: http://earthquake.usgs.gov/earthquakes/recenteqsww...
There's *A LOT*, by the way.
Also:
MOTORVATOR said:
And the tsunami itself, whilst dreadful, wasn't as high as I expected in my mind given the size of the quake. Had the epicentre been further offshore or in a deeper ocean trench would we have seen a much larger tsunami or conversely a much lesser one if occurring in shallower water.?
Not that high?MOTORVATOR said:
Rather than bogging down the up to the minute discussion on Japan I thought I'd ask this here.
My understanding is that in the lead up to this quake there were a number of prior shocks that they only now can say were preshocks.
But can they determine that this the end of it or is it possible that an even bigger quake could occur over the next few days and this one get's downgraded to preshock?
If this was a foreshock, then the scale of the earthquake to come would be completely unimaginable. To put it into context, today's earthquake was something like the 5th or 6th strongest in recorded history. My understanding is that in the lead up to this quake there were a number of prior shocks that they only now can say were preshocks.
But can they determine that this the end of it or is it possible that an even bigger quake could occur over the next few days and this one get's downgraded to preshock?
So, I guess it's possible but I really hope it isn't.
MOTORVATOR said:
Also any sensible discussion thoughts on whether astrological conditions do influence these in any way? Not from a direct cause, as we all know that this is just a release of built up pressure, but could it be the bit that provides the final trigger rather than waiting for just a pressure fault to occur, hence the coincedence?
What co-incidence are you referring to?If you're interested in plate tectonics I suggest a trip to Iceland....it's on the boundary of the European and North American plates. Here's an example
http://www.flickr.com/photos/chrisjohnbeckett/3516...
http://www.flickr.com/photos/chrisjohnbeckett/3516...
ewenm said:
MOTORVATOR said:
Also any sensible discussion thoughts on whether astrological conditions do influence these in any way? Not from a direct cause, as we all know that this is just a release of built up pressure, but could it be the bit that provides the final trigger rather than waiting for just a pressure fault to occur, hence the coincedence?
What co-incidence are you referring to?
ks about big moons, armaggedon etc without actually looking. Today the moon was some 40,000km off the closest it will come in 8 days time.I was just interested to know what anybody thought of the possibility of influence however small.
I think that maybe, just maybe, the effect of a "close moon" could bring on an earth quake, but only one that would have happened at some near point in the future anyway. It certainly couldn't "create" a quake from nowhere, as the plate stiction and buckling has to build up over a long time, to be suddenly released in a short, high energy event. So that just leaves the question, whats worse, an earthquake today, or one say a week on tuesday?? (the obvious answer being neither!)
Max_Torque said:
I think that maybe, just maybe, the effect of a "close moon" could bring on an earth quake, but only one that would have happened at some near point in the future anyway. It certainly couldn't "create" a quake from nowhere, as the plate stiction and buckling has to build up over a long time, to be suddenly released in a short, high energy event. So that just leaves the question, whats worse, an earthquake today, or one say a week on tuesday?? (the obvious answer being neither!)
I'm guessing if the maybe just maybe was correct then the earlier it happens the better as there is less energy built up in it?
MOTORVATOR said:
Rather than bogging down the up to the minute discussion on Japan I thought I'd ask this here.
My understanding is that in the lead up to this quake there were a number of prior shocks that they only now can say were preshocks.
But can they determine that this the end of it or is it possible that an even bigger quake could occur over the next few days and this one get's downgraded to preshock?
Also any sensible discussion thoughts on whether astrological conditions do influence these in any way? Not from a direct cause, as we all know that this is just a release of built up pressure, but could it be the bit that provides the final trigger rather than waiting for just a pressure fault to occur, hence the coincedence?
And the tsunami itself, whilst dreadful, wasn't as high as I expected in my mind given the size of the quake. Had the epicentre been further offshore or in a deeper ocean trench would we have seen a much larger tsunami or conversely a much lesser one if occurring in shallower water.?
Sort of. What can happen is that you'll get successive earthquakes (aftershocks) in the same region as the original after a major quake. Sometimes, these small aftershocks can surpass the magnitude and intensity of the original quake - and they'll become the main quake and the previous largest quake as you said will become a 'foreshock'. If it's from a different region it counts as a different quake and you can get one leading to another quake. Typically, the aftershocks follow a similar pattern of decaying ferocity and frequency, with the first 24 hours being the most dangerous. Have a look at Omori's' Law and Bath's Law if you're remotely interested, it's hardly the most exciting aspect of Geology though!My understanding is that in the lead up to this quake there were a number of prior shocks that they only now can say were preshocks.
But can they determine that this the end of it or is it possible that an even bigger quake could occur over the next few days and this one get's downgraded to preshock?
Also any sensible discussion thoughts on whether astrological conditions do influence these in any way? Not from a direct cause, as we all know that this is just a release of built up pressure, but could it be the bit that provides the final trigger rather than waiting for just a pressure fault to occur, hence the coincedence?
And the tsunami itself, whilst dreadful, wasn't as high as I expected in my mind given the size of the quake. Had the epicentre been further offshore or in a deeper ocean trench would we have seen a much larger tsunami or conversely a much lesser one if occurring in shallower water.?
Japan lies smack bang on an area which is known as the 'Ring of Fire', basically an area of really high tectonic plate activity, hence there's so many volcanoes and earthquakes in the region. They get hundreds of earthquakes a year, with most of them barely registering, but because subduction is occurring (one plate being squeezed beneath another and almost consumed), hence the plate grumbling and the multiple small shocks, it's prone to occasional tectonic slip and colossal earthquakes like today.I forget the statistics but there's a massive percentage of the world's volcanic activity and earthquakes in this area.
As for the effect of the moon - it has nothing to do with it. Of course the sun and moon do affect weather, but plate tectonics are a completely different ball game. Sadly, when there are coincidences like this occur, people are going to jump to conclusions (there was a 'supermoon' in 2005, and Hurricane Katrina). Have a look at the Bad Astronomy blog (link below) and other more informed sources (stay away from the media when it comes to this stuff, it's shocking how the facts get twisted) and form your own opinions. The daily wail should be flogged in public for their scaremongering pseudoscience.
http://blogs.discovermagazine.com/badastronomy/201...
The Moons gravity will have AN effect, whether that is enough to provide the trigger is another thing. It does move quite a bit of water about as we can see from the tides.
Tsunami size in terms of depth depends on loads of stuff, amount of vertical motion at fault line, length of the fault which moved, ocean floor profile, coastal features, tide (moon again!), etc.
Amount of energy release was bloody massive!
Tsunami size in terms of depth depends on loads of stuff, amount of vertical motion at fault line, length of the fault which moved, ocean floor profile, coastal features, tide (moon again!), etc.
Amount of energy release was bloody massive!
The upper mantle consists of continents and islands mainly,and they effectively 'float' on the surface of the planet.When one plate meets another
is when earthquakes occur.Usually the more dense plate will force the other beneath it.Sometimes mountain ranges are pushed up when these plates meet,like the Alps.
is when earthquakes occur.Usually the more dense plate will force the other beneath it.Sometimes mountain ranges are pushed up when these plates meet,like the Alps.
Gnits said:
The Moons gravity will have AN effect, whether that is enough to provide the trigger is another thing. It does move quite a bit of water about as we can see from the tides.
Tsunami size in terms of depth depends on loads of stuff, amount of vertical motion at fault line, length of the fault which moved, ocean floor profile, coastal features, tide (moon again!), etc.
Amount of energy release was bloody massive!
The effect of tide on plate tectonics is not a well researched field (at least it wasn't when I was at university). But it's entirely plausible that it could have an effect -the water moved around by the tides does carry a hell of a lot of weight. Tsunami size in terms of depth depends on loads of stuff, amount of vertical motion at fault line, length of the fault which moved, ocean floor profile, coastal features, tide (moon again!), etc.
Amount of energy release was bloody massive!
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