North and South Hemisphere are they mass balanced

**arauca** · 03-24-12, 08:39 PM

Is there a mass balance between the north hemisphere and the South hemisphere.
Should the mass imbalance affect the tilt our planet ?

**arauca** · 03-25-12, 07:32 PM

Originally Posted by arauca

Is there a mass balance between the north hemisphere and the South hemisphere.
Should the mass imbalance affect the tilt our planet ?

apparently there is not much interest. but:
For information to anyone :
See the graphs also.
http://phl.upr.edu/library/notes/ana...flandandoceans

Here we present a quick analysis of the distribution of landmasses from the data generated as part of our Visible Paleo-Earth project. Previous post (here and here) showed the analysis done to a few periods. Now we have all 30 periods to compare (all individual analysis attached as a single ZIP file at the end). We plotted the distribution of land and ocean areas from 750 Mya to today, including North to South, and East to West ratios (Figure 1). The analysis shows an increasing small trend in the land to ocean ratio during this period. Suggesting that our planet has been steadily loosing oceanic water in the last 750 million years, among other explanations. There are associated variation due to movement of landmasses and glacial periods, but this trend seems specially true after 500 Mya.

Water can escape from our planet in various ways. Photolysis in the upper atmosphere dissociates water into hydrogen and oxygen, the hydrogen escapes to space and the oxygen usually combines with the crust creating oxides or forming carbon dioxide. Water also escapes by thermal processes. Some water is replenished from cometary impacts or from geological activity. Also impacts contribute to atmospheric and oceanic erosion (Chyba, 1990). The protection of Earth's magnetic field also complicate matters. All these factors combine to a net loss of water to space at a very small rate. This rate changed through time due to variations in solar luminosity, terrestrial heat flow, impact rates, crust size, and carbon reservoirs.

We fitted a straight line to the land to ocean ratio trend to get a sense of this potential oceanic loss (Figure 2). Assuming the same trend before 750 Mya, the fit suggest that landmasses started to appear about 1,900 Mya. However, we know that continents grew rapidly between 3,000 and 2,700 Mya (Condie, 1986), and there is even evidence of continental crust as old as 4,400 Mya (Wilde et al., 2001). We can explain this by assuming that the loss rate was slower in the past, probably due to the lower solar luminosity. The sea-leve curve (Hallam, 1984) was included in a plot of the land to ocean ratio for comparison (Figure 3).

If we assume the same loss rate in the future, our planet will have the same land and ocean area by 3,000 million years from today (now 29% land, 71% ocean). However, solar luminosity will increase due to helium fusion in the Sun and it is expected that Earth will loss its oceans much earlier, between 1,000 to 2,000 million years from now (Sackmann et al., 1993).

**Rhaedas** · 03-25-12, 08:32 PM

They are always in flux due to the tidal movement. From a percentage of the total Earth's mass, probably not a lot.

**arauca** · 03-26-12, 10:07 AM

Originally Posted by Rhaedas

They are always in flux due to the tidal movement. From a percentage of the total Earth's mass, probably not a lot.

Have you had a chance to see the charts ?

**origin** · 03-26-12, 10:21 AM

Originally Posted by arauca

apparently there is not much interest.

No, I think everyone just figured you would post the answer (that you already had) to your question, which you did.

**adoucette** · 03-26-12, 10:22 AM

Is the mass of the ice on top of the land considered when Antarctica and Greenland's mass is considered?

**arauca** · 03-26-12, 01:29 PM

Originally Posted by origin

No, I think everyone just figured you would post the answer (that you already had) to your question, which you did.

Be nice , stop talking for other people .

**arauca** · 03-26-12, 01:30 PM

Originally Posted by adoucette

Is the mass of the ice on top of the land considered when Antarctica and Greenland's mass is considered?

What ever it is , my question is the load disrtibution

**adoucette** · 03-26-12, 01:45 PM

So you don't know?

**Rhaedas** · 03-26-12, 01:59 PM

Originally Posted by arauca

Have you had a chance to see the charts ?

Actually the chart deals with area, not mass, so everything adds to 100%. It's really has little to do with your question as you phrased it. And your question, while a valid one, is a very complicated one. But as I said, the mass distribution does fluctuate, quickly with the tides, very slowly with continental movement and any other mass loss or gain. But overall, the surface area, even counting the thickness of the oceans and continents, are only a small part of the total earth mass, so while it will affect the spin and tilt, it's minuscule. Can I show the math right now, no...but I'm sure if I dove in and did some research I could find numbers to reflect it.

**arauca** · 03-26-12, 05:28 PM

Originally Posted by adoucette

Is the mass of the ice on top of the land considered when Antarctica and Greenland's mass is considered?

Interesting : Could it be as the poles ice melts ( depending which pole ) the earth axis will shift and so will the the hemisphere climate ?

**arauca** · 03-30-12, 11:05 AM

The earth gravity is not evenly distributed on the earth , and the earthquakes follow the line along the the line of higher gravity along the pacific ring of fire and along American continent west coast

**Rhaedas** · 03-30-12, 02:28 PM

http://www.universetoday.com/67435/e...ty-seen-in-hd/

That's not an exact correlation. Earthquakes are more frequent along fault lines because...well, fault lines slip because the whole thing is in motion and stress. Keep in mind that that gravity field map required very high precision, so it's not like we're talking about big values of difference between the high and low points. So the main cause of earthquakes has much more to do with plate tectonics of the earth.

**arauca** · 03-30-12, 03:35 PM

Originally Posted by Rhaedas

http://www.universetoday.com/67435/e...ty-seen-in-hd/

That's not an exact correlation. Earthquakes are more frequent along fault lines because...well, fault lines slip because the whole thing is in motion and stress. Keep in mind that that gravity field map required very high precision, so it's not like we're talking about big values of difference between the high and low points. So the main cause of earthquakes has much more to do with plate tectonics of the earth.

If you look at this map carefully and compare the pacific and the Atlantic zone and give your impartial opinion
http://bgi.omp.obs-mip.fr/index.php/...avity-Map-WGM#
or I might find you same more detailed

http://www.zonu.com/detail-en/2009-1...the-world.html

Now if you follow the path pf earthquakes ion the Paccific by Indonesia Japan Alaska
At the same time you can follow a path through China Turkey into Italy
I am familiar with the fault lines.

**Rhaedas** · 03-30-12, 04:37 PM

I would suspect that you find greater values at fault lines due to the compression of the crust there. Density will affect gravity.

Also, look at the values being discussed. The range of the map is +/- 60 mGals difference. Standard gravitation is 976 to 983 Gals, so this map is showing very small percentages from normal.

**arauca** · 03-30-12, 05:45 PM

Originally Posted by Rhaedas

I would suspect that you find greater values at fault lines due to the compression of the crust there. Density will affect gravity.

Also, look at the values being discussed. The range of the map is +/- 60 mGals difference. Standard gravitation is 976 to 983 Gals, so this map is showing very small percentages from normal.

I appreciate your comment . but whatever the difference are small so they are, should they be accepted ?
Because they are at fault would it not indicate that there below the crust some anomaly ?

**Rhaedas** · 03-30-12, 06:16 PM

Alright. Why do we not get earthquakes at all the places that have higher gravity? Why do we get earthquakes at faults that are at lower gravity? If this was the root cause there would be correlation.

Why do we find some points on earth that have higher gravity? Simple, there's more mass there. Either because of the composition or the density, or a combination. Some faults have rocks at high pressure, some don't, so we'll find variations there.

**arauca** · 03-30-12, 08:18 PM

Originally Posted by Rhaedas

Alright. Why do we not get earthquakes at all the places that have higher gravity? Why do we get earthquakes at faults that are at lower gravity? If this was the root cause there would be correlation.

Why do we find some points on earth that have higher gravity? Simple, there's more mass there. Either because of the composition or the density, or a combination. Some faults have rocks at high pressure, some don't, so we'll find variations there.

It could very well be if there is a subduction, naturally the thickness of the crust will be greater sitting in the mantle until, it become dissolved into the mantle. My point is that it seams earthquakes follow the higher gravity point on the earth.

**~~RealityCheck~~** · 04-01-12, 10:39 PM

Originally Posted by arauca

It could very well be if there is a subduction, naturally the thickness of the crust will be greater sitting in the mantle until, it become dissolved into the mantle. My point is that it seams earthquakes follow the higher gravity point on the earth.

Ahhh, I see what you're getting at.

Just like if the ice melts in summer at the poles and redistributes around the oceans until the next winter, and so making the poles 'more gravity effect' when of 'local weight' is greater from additional winter ice....

....you are 'mirroring' this sort of local weight/gravity' compared to 'distributed weight' variation to gravity effect between when subducted materials 'build up' locally in the mantle as solids are accumulated there and their associated gravity effects accumulated also, and when the 'front' of that subduction accumulations are 'melted' and distributed around the internal 'ocean' of magma and so decreasing the gravity effect previously associated with the localised the formerly solid accumulations before 'melting' into magma and distributed 'non locally'?

Am I reading you right, mate? If so, you have a very interesting take on it regarding 'gravity' effect variations between solid local masses and melted 'non local' distribution of the masses and the gravity effects that go with it. I am curious what the discussion about this will produce and whether it does have any (or not) implications for the current prediction models for earthquakes, volcanoes and gravity-redistribution effects on plate techtonics in general.

Sort of UNDER-CRUST 'mountains' mirroring the on-crust mountains created by plate collisions/subductions (except the on-crust mountain material takes longer to 'erode away' and redistribute less widely, while the under-crust 'mirror' mountain material melts more quickly and redistributes more widely in the magma 'ocean' so gravity effect variations would 'cycle' more frequently than would gravity variations associated with on-crust mountain 'cycles')?

It would be interesting to know what data and theories currently take into account about these factors/cycles as you imply with your OP etc posts.

Thanks for the intriguing OP arauca, it certainly makes one think about what's going on in, and on, the earth in a slightly different way!

Back tomorrow. Cheers!

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