[Arpe]

Source: Japan Moves, Earth Shifts on Axis - News - GIM International

Japan Moves, Earth Shifts on Axis
15/03/2011
Japan's earthquake appears to have moved the main island by 2.4 metres and shifted the Earth on its axis, according to scientists at Italy's National Institute of Geophysics and Volcanology. Speaking on Saturday, they said preliminary results of a study showed that Friday's 8.9-magnitude quake shifted the Earth on its rotational axis by nearly 10 centimetres.

‘We know that one GPS station moved (2.4 metres), and we have seen a map from GSI (the Geospatial Information Authority) in Japan showing the pattern of shift over a large area is consistent with about that much shift of the land mass,' Kenneth Hudnut, a US Geological Survey geophysicist, told broadcaster CNN.

This quake's impact on the axis was much greater than that of the 9.1-magnitude Indonesian earthquake in 2004, and probably second only to the Chilean quake of 1960, said the institute's director, Antonio Piersanti in a statement.

In 2010, scientists from US space agency NASA said the 8.8- magnitude earthquake that struck Chile that February was so strong that it may have shortened the length of a day.

Using a computer model, Richard Gross, a scientist at the space agency's Jet Propulsion Laboratory in California, found the quake likely shifted the Earth's axis by about 8 centimetres.

The shift of the axis on which the planet's mass is balanced slightly changes the length of time it takes the Earth to make a complete rotation; after the Chilean quake it meant that each day was about 1.26 microseconds shorter. A microsecond is one-millionth of a second.

The infinitesimal shift was slightly more than a similar change after the 2004 tremblor, Gross said. Even though the magnitude of the Chilean quake was slightly less, its location and the angle of its fault lines made it more likely to shift the axis.

The 2004 earthquake and tsunami in Southeast and South Asia permanently speeded up the Earth's rotation, shortening the succeeding days by about three microseconds, Gross said then. The time change occurred when that quake moved the Earth's axis by 2.5 centimetres.

[Chex]

Wow, crazy stuff! Well, the more we humans contaminate this giant mud ball, the more it will show us why we should be respecting it. It's just unfortunate that the ones to pay the bill will be generations down the line, for the atrocities started as far back as the industrial revolution and spiking in the 70's to now.. even though we claim to be doing what we can. Putting the almighty dollar above the eco system is just ignorant, but I doubt that will ever change until it is far far too late!

[RoxnDox]

Wow, crazy stuff! Well, the more we humans contaminate this giant mud ball, the more it will show us why we should be respecting it. It's just unfortunate that the ones to pay the bill will be generations down the line, for the atrocities started as far back as the industrial revolution and spiking in the 70's to now.. even though we claim to be doing what we can. Putting the almighty dollar above the eco system is just ignorant, but I doubt that will ever change until it is far far too late!

Umm, Chex, this is a result of an earthquake, not a result of anything we humans have done. Quakes like this have been going on for billions of years, as long as this planet has had crustal plates being recycled thru tectonic motions... Even a catastrophic meltdown would be nothing more than a tiny, barely noticeable blip and would be gone in the blink of an eye, as far as the planet is concerned.

We should be cleaner in what we do, and we should take a damn sight better care of the planetary ecosystem than we do, but in the long run (geologically speaking) whatever we do is pretty insignificant. As are we.

Jim

[Chex]

I wasn't meaning that we caused the quakes, but I'm sure our polluting and drilling etc are having a direct negative impact. And here I thought someone was down between the plates with a pry bar making a mess of things..

[RioRico]

Fire and Ice: Melting Glaciers Trigger Earthquakes, Tsunamis and Volcanos
Geologists Say Global Warming Expected to Cause Many New Seismic Events

Do I believe this? Ah, not really.
Is it worth studying? Yup.
Can we get a grant?

[Chex]

Sure, I grant you time off to go study it.. enjoy!

[Ratmagiclady]

Fire and Ice: Melting Glaciers Trigger Earthquakes, Tsunamis and Volcanos
Geologists Say Global Warming Expected to Cause Many New Seismic Events

Do I believe this? Ah, not really.
Is it worth studying? Yup.
Can we get a grant?

It's definitely worth studying, not cause the melting sometimes likely triggers some earthquakes (Less likely in the case of some kinds of faults, but sure it could and sometimes seems to happen with smaller quakes, and you know the weight of glaciers is enough to affect the land and push down on whole landscapes,) and certainly it's not like you can blame the whole Ring of Fire on it, but there is a lot of weight shifting around.

The notion would be that there's a lot of load around these faults, which tends to build up until something breaks or lets go, and at this point we never know what might be 'the last straw' that unloads that. The crust is generally pretty plastic, as well, so you never know, a kilojoule here, a kilojoule there, so by the time you get a ways down the line you could be kicking out some pretty serious chocks on some pretty big fault-loads.

The key word would be *trigger,* though, not 'cause' in the sense of providing the energy or being a necessary condition for a given quake to happen ever. You could pretty easily imagine a chain of events where kicking a twig sets off a rockslide, it doesn't mean that you're safe under a big pile of rocks if you banned twigs from it.

Why it's worth studying is cause if we want early warning about earthquakes, one of the most promising ways of doing it is if we can study and map all the loads down there deep under faults, it's very possible that with enough computing power we could keep a real-time model of most of the loads on some worrisome fault areas, and thus start building a profile of what the precursor activity would sound like, ...like with a fingerprint-sampling method, (where they actually match a fairly small number of comparison points, but it's enough to distinguish between about every fingerprint on Earth, mathematically-speaking. ) if, with real-time monitoring, you start seeing a match of certain projected micro-tremors or other signs, then you might start being able to forecast when it might all come down.


Which, if you wanted to study the effect of melting glaciers and rising sea levels on local seismic activity, you might learn a lot about how to do. That the glaciers are melting is bad on all kinds of counts, but it's also potentially relatively-easier to get data, cause in those glaciers and other surface phenomena is a whole bunch of relatively-easy-to-measure and calculate (compared to deep-underground) *weight* that's *changing on human-study timescales* and doing so fairly observably.

Which basically means, to test that theory, you might be able to correlate a fairly-easil-chartable input with what data can be gleaned about what's going on deeper in the ground. Could be very worthwhile.

In terms of disaster potentials, rising sea levels and coastal erosion and other changes a lot of inhabited land isn't really built around do somewhat increase the *vulnerability* to things like tsunami, (and of course storm-surge,) whatever the source of those.


Of course, in terms of what could be *done* about what's causing all that glacial melt in the first place, well, I think the bigger lessons of this disaster, if not previous ones, is how darn vulnerable these big power grids and fossil fuel infrastructures are to things like this, and how just maybe reliance on certain big fossil fuel and nuclear systems for darn near *everything* just isn't the guarantee of prosperity it's claimed to be by some, to begin with...

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Last edited by Ratmagiclady; 03-21-2011 at 05:58 AM.

[Chex]

Here in BC, Canada we've often joked about when the big one hits our coast it very well could take the entire Vancouver island. Places like Hope could become ocean front etc.. After seeing the magnitude of damage from Japans Tsunami I can see how far inland it could go.. of course it wouldn't stay though. I was listening to David Suzuki the other day, and he was saying how fast the ice is receding in Greenland, and when it all melts, it could raise ocean levels by 1-2 meters. even scarier is what he said about a giant iceberg that is slowly melting in Antarctica could raise ocean levels up to 6 meters. Sure people would have time to react to melted ice.. but think of the land displacement! Think of how many people live in within the 20-40 feet above sea level range...

[MRRiley]

Happens just about every time there is a big quake... the next one will just knock it in a different direction... The earth changes every day...

[Chex]

Yup, Just makes me wonder why so many people choose to live in such area's.. I agree Japan is beautiful, as is Hawaii, but with all the possibilities of catastrophy I think I would consider relocating. Obvisouly thats easier said than done for most people and their families.. but if its something you really wanted (a safer environment) then you would do what you can to work towards it. To think of how many people live along the ring of fire, and depend on its ocean wildlife for food etc, it sure can rear its ugly head on its dependants.

[RoxnDox]

I wasn't meaning that we caused the quakes, but I'm sure our polluting and drilling etc are having a direct negative impact. And here I thought someone was down between the plates with a pry bar making a mess of things..

Ah, my bad... I agree, we do a lot of things that have a short-term (by my standards) negative impact. And we ought to be doing a better job as stewards of the resources available to us, if we wish our species and associated ecosystems to continue as they are...

Jim

[RoxnDox]

Yup, Just makes me wonder why so many people choose to live in such area's.. I agree Japan is beautiful, as is Hawaii, but with all the possibilities of catastrophy I think I would consider relocating. Obvisouly thats easier said than done for most people and their families.. but if its something you really wanted (a safer environment) then you would do what you can to work towards it. To think of how many people live along the ring of fire, and depend on its ocean wildlife for food etc, it sure can rear its ugly head on its dependants.

Heck, everywhere has some sort of hazard... I grew up in hte Seattle area. We never worried back then about really big quakes, but we knew there were reasonably big ones, and we knew about the various volcanic hazards. When I was in the Midwest (Nebraska) it was all about tornadoes and blizzards. Florida has its hurricanes. Etc. etc... Wherever ya go, *something* is gonna get you eventually And you have to live somewhere, so might as well accept the risks and live where you want.


Jim

[Chex]

Yeah but how many lives do blizzards and hurricanes and even volcano's take commpared to earthquakes and tsunami's... I live in the snowbelt just west of the Rockies in BC, Canada, we have plenty of avalanches and lots of snow.. the only thing that could really pose a major catastrophy here would be if one of the dams on the river let go and washed us down the valley.. But only the one dam would actually poise a threat by only giving us about 5 minutes to prepare. The other would give us about 30 minutes or more.

[RoxnDox]

Yeah but how many lives do blizzards and hurricanes and even volcano's take commpared to earthquakes and tsunami's... I live in the snowbelt just west of the Rockies in BC, Canada, we have plenty of avalanches and lots of snow.. the only thing that could really pose a major catastrophy here would be if one of the dams on the river let go and washed us down the valley.. But only the one dam would actually poise a threat by only giving us about 5 minutes to prepare. The other would give us about 30 minutes or more.

Oh, I don't argue that tsunamis can cause much larger casualty counts. Deaths by direct quake effects are pretty rare, what causes most of them is buildings collapsing due to shoddy construction (i.e. Haiti, China, various Middle Eastern countries), and, of course, tsunamis. My point is simply that there's no place truly "safe", it's all a matter of risks vs benefits. River valleys make good farming but carry the risk of floods. Volcanos produce rich soils but carry the risk of mudslides, lahars, eruptions, etc. Coasts support trade by ship as well as fishing (and are the prettiest places to live ) but carry the risk of tsunamis, storms, etc. Inland prairies are (boringly) nice farmland and ranchland but you get tornados and blizzards. It's just a balance, no matter where you are.

Jim (on Puget Sound, in quake country but high enough to not worry about waves or volcanos)

[Chex]

Yeah but the way I see things here.. I have more of a chance of being bored to death than a natural disaster getting me.