One for the geologists. It took twenty years, so this was the slowest “CT” scan ever done. They used seismic waves from Earthquakes and “numerical simulations” (and we know what they are). But possibly these models are not worthless. Apparently these blobs of hot rock under the Pacific and Africa are 5,000 km across, and may have been there for 250 million years. In any case, the full press release is below. There’s no mention of heat that might be coming up from this big ball of magma and how that might influence ocean currents, or whether it even changes on a timescale that matters (Hey we have one “CT” scan. We can’t get a trend from that. I just wonder… — Jo
..
CT scan of Earth links deep mantle plumes with volcanic hotspots
[Science Daily] Scans prove that plumes of hot rock anchored at core-mantle boundary rise to form island chains
University of California, Berkeley, seismologists have produced for the first time a sharp, three-dimensional scan of Earth’s interior that conclusively connects plumes of hot rock rising through the mantle with surface hotspots that generate volcanic island chains like Hawaii, Samoa and Iceland.
Essentially a computed tomography, or CT scan, of Earth’s interior, the picture emerged from a supercomputer simulation at the Department of Energy’s National Energy Research Scientific Computing Center (NERSC) at the Lawrence Berkeley National Laboratory.
While medical CTs employ X-rays to probe the body, the scientists mapped mantle plumes by analyzing the paths of seismic waves bouncing around Earth’s interior after 273 strong earthquakes that shook the globe over the past 20 years.
Previous attempts to image mantle plumes have detected pockets of hot rock rising in areas where plumes have been proposed, but it was unclear whether they were connected to volcanic hotspots at the surface or the roots of the plumes at the core mantle boundary 2,900 kilometers (1,800 miles) below the surface.
The new, high-resolution map of the mantle — the hot rock below Earth’s crust but above the planet’s iron core — not only shows these connections for many hotspots on the planet, but reveals that below about 1,000 kilometers the plumes are between 600 and 1,000 kilometers across, up to five times wider than geophysicists thought. The plumes are likely at least 400 degrees Celsius hotter than surrounding rock.
“No one has seen before these stark columnar objects that are contiguous all the way from the bottom of the mantle to the upper part of the mantle,” said first author Scott French, a computational scientist at NERSC who recently received his Ph.D. from UC Berkeley.
Senior author Barbara Romanowicz, a UC Berkeley professor of earth and planetary science, noted that the connections between the lower-mantle plumes and the volcanic hotspots are not direct because the tops of the plumes spread out like the delta of a river as they merge with the less viscous upper mantle rock.
“These columns are clearly separated in the lower mantle and they go all the way up to about 1,000 kilometers below the surface, but then they start to thin out in the upper part of the mantle, and they meander and deflect,” she said. “So while the tops of the plumes are associated with hotspot volcanoes, they are not always vertically under them.”
Ancient anchors
The new picture also shows that the bases of these plumes are anchored at the core-mantle boundary in two huge blobs of hot rock, each about 5,000 kilometers in diameter, that are likely denser than surrounding rock. Romanowicz estimates that those two anchors — directly opposite one another under Africa and the Pacific Ocean — have been in the same spots for 250 million years.
French and Romanowicz, who also is affiliated with the Institut de Physique du Globe and the Collège de France in Paris, will publish their findings in the Sept. 3 issue of the British journal Nature.
Earth is layered like an onion. An exterior crust contains the oceans and continents, while under the crust lies a thick mantle of hot but solid rock 2,900 kilometers thick. Below the mantle is the outer core, composed of liquid, molten iron and nickel, which envelopes an inner core of solid iron at the center of the planet.
Heated by the hot core, the rock in the mantle rises and falls like water gently simmering in a pan, though this convection occurs much more slowly. Seismologists proposed some 30 years ago that stationary plumes of hot rock in the mantle occasionally punched through the crust to produce volcanoes, which, as the crust moved, generated island chains such as the Galapagos, Cape Verde and Canary islands.
The Hawaiian Islands, for example, consist of 5 million-year-old Kauai to the west but increasingly younger islands to the east, because the Pacific Plate is moving westward. The newest eruption, Loihi, is still growing underwater east of the youngest island in the chain, Hawaii.
Until now, evidence for the plume and hotspot theory had been circumstantial, and some seismologists argued instead that hotspots are very shallow pools of hot rock feeding magma chambers under volcanoes.
Romanowicz, who uses seismic waves to study Earth’s interior, had previously worked with French, then a graduate student, on a tomographic model of the upper 800 kilometers of the mantle, which showed periodic hot and cold regions of rock underlying hotspot volcanoes. The new study completes that picture down to the core-mantle boundary.
She noted that if higher temperature alone were responsible for the rising plumes, they would be only 100-200 kilometers wide, ballooning out only when they approach the surface. The fact that they appear to be five times wider in the lower mantle suggests that they also differ chemically from the surrounding cooler rock.
This supports models where the material in the plume is a mixture of normal mantle rock and primordial rock from the dense rock anchoring the plume at the core-mantle boundary. In fact, lava emerging from hotspot volcanoes is known to differ chemically and isotopically from lava from other volcanoes, such as those erupting at subduction zones where Earth’s crust dives into the upper mantle.
The supercomputer analysis did not detect plumes under all hotspot volcanoes, such as those in Yellowstone National Park. The plumes that feed them may be too thin to be detected given the computational limits of the global modeling technique, French said.
Millions of hours of computer time
To create a high-resolution CT of Earth, French used very accurate numerical simulations of how seismic waves travel through the mantle, and compared their predictions to the ground motion actually measured by detectors around the globe. Earlier attempts by other researchers often approximated the physics of wave propagation and focused mainly on the arrival times of only certain types of seismic waves, such as the P (pressure) and S (shear) waves, which travel at different speeds. French used numerical simulations to compute all components of the seismic waves, such as their scattering and diffraction, and tweaked the model repeatedly to fit recorded data using a method similar to statistical regression. The final computation required 3 million CPU hours on NERSC’s supercomputers, though parallel computing shrank this to a couple of weeks.
Romanowicz hopes eventually to obtain higher resolution supercomputer images of Earth’s interior, perhaps by zooming in on specific areas, such as that under the Pacific Ocean, or by using new data.
“Tomography is the most powerful method to get this information, but in the future it will be combined with very sensitive gravity measurements from satellites and maybe electromagnetic sounding, where people do conductivity measurements of the interior,” she said.
Full press release Berkley News.
Wonder how this ties in with plate tectonics, if at all.
61
Yes. I would say the science is not settled.
70
This sadly is not a clear map as it shows continents and present day tectonic plates in the same colour. Note a line between Australia and Antarctica which marks the present day tectonic plate and active spreading ridge between two continents. It looks like the hot spot zone follows that line only partially and then stops. Since active spreading continues along the black line I see no reason why this hotspot should not continue. Indonesia is cold, which is strange. The Western Africa trend appears to correspond to mid-Atlantic spreading ridge with Iceland being a hot spot as it should be. However this is on the edge of the image which makes it unclear.
This is a classic situation in science. People spend their money, time and intellectual prowess to generate images like this and guys like me immediately interpret and look for inaccuracies. This however is a normal process. Such images generate more questions and the scientific dance commences ie science never is settled.
90
I will have to read the paper to really understand this graphic. Previous oceanographic work has picked up tectonic mega trends that are not easily explained by current Plate Tectonic Theory.
International Geology Review
The North Pacific Megatrend
N. Christian Smoot & Dong R. Choi
pages 346-370
http://www.tandfonline.com/doi/abs/10.2747/0020-6814.45.4.346?journalCode=tigr20#.VezXd5eyEgQ
ABSTRACT: Megatrends are trans-basin features comprised of fracture zones and seamount/island chains. They appear to be hot lines rather than isolated hot spots. The North Pacific Megatrend begins in Japan, crosses the trench in the form of the Geisha Guyots, skirts along the northern Mapmaker Seamounts, encompasses the Hawaiian chain, and passes through the Clipperton and Clarion fracture zones to the East Pacific Rise. The Central Pacific Megatrend bifurcates at the East Pacific Rise (Easter vortex), and the northern branch passes northward to meet the North Pacific Megatrend. The excess magma in the channel is directed eastwardly under the Galapagos chain to form the Cocos and Carnegie ridges, which pass onto the South American continent. This feature is surrounded by Precambrian mantle material and underlain by an earthquake band.
00
Fascinating, as a geologist it makes sense to me.
70
Can you assist with my questions at #18, below?
00
East Pacific ridge is the fastest spreading, and yet no deep rooted heat plume, no obvious up-welling.
I fail to see how that can make good sense or any sense to a geo, if PT mechanics is the accepted model of spreading.
00
“French used very accurate numerical simulations of how seismic waves travel through the mantle, and compared their predictions to the ground motion actually measured by detectors around the globe.”
Sounds like model validation. I wonder what other branch of science could learn from this?
60
I actually had a bit of a problem with that very sentence. How are the authors able to determine that their numerical simulations are “very accurate”? They surely aren’t confusing accuracy and precision, are they? If the models are “accurate” solely because their results coincide with existing real-world measurements, what are the simulations for?
I’m guessing that more research is needed.
20
What’s happening in Hawaii, according to the new “CT”? Volcano, HI looks like a good place to settle–just cool enough in winter to grow apples and apricots, A little too cool to get bananas. Tropical latitude, temperate growing climate. But, it does seem at risk for lava flow from Kilauea. Anyway, you can fly over the big island, and see lava pools, and clouds arising from the lava flow into the Pacific.
Also, what is happening in the Antarctic? Is ice being melted from below, or not?
40
Yes it is being melted from below:
University of Texas: Researchers Find Major West Antarctic Glacier Melting from Geothermal Sources
First evidence of under-ice volcanic eruption in Antarctica – 2008
(wwwDOT)bas.ac.uk/media-post/first-evidence-of-under-ice-volcanic-eruption-in-antarctica/
Underwater volcanoes discovered
http://www.livescience.com/15006-underwater-volcanoes-discovered-antarctica.html
20
The Arctic also has major geothermal activity. Note the dance around any impact on Arctic ice melt and emphasis on CO2 release.
Volcanoes Erupt Beneath Arctic Ice — June 27, 2008
40
Following up on the possible Volcano-Climate link.
Iceland Volcano Cleared in Case in Extreme Winter of 1783-84 — April 13, 2011
(Rosanne D’Arrigo publications: (WWWDOT)researchgate.net/profile/Rosanne_DArrigo/publications
Just in time for the gathering of Paris-ites.
Polar ice cores reveal volcanic eruptions – July 2015
ANYTHING to get rid of a solar link to climate. (There is some work being done on connecting low solar activity to increased earthquake/volcanoes.)
Rosanne D’Arrigo also changes her tune in this more recent publication:
Volcanic cooling signal in tree ring temperature records for the past millennium: VOLCANISM AND TREE RING RECORDS 08/2013
(wwwDOT)researchgate.net/publication/260722295_Volcanic_cooling_signal_in_tree_ring_temperature_records_for_the_past_millennium_VOLCANISM_AND_TREE_RING_RECORDS
Stacked Volcanoes Falsify Models (May 25, 2013) by Willis Eschenbach
20
Following up on the solar cycle -volcanic activity possibility.
Does the solar cycle modulate seismic and volcanic activity? October 1989
A May 3, 2013 study by a department of the US government says They found no significant pattern between solar activity and more or larger earthquakes.
This is interesting because THE HOCKEY SCHTICK reported a few months earlier, on January 17, 2013, a new paper:
10
Now that’s what I call global warming! Now, how to stop it?
80
Send down James Mason and Pat Boone to throw Naomi Klein into the core, she’s the biggest wet blanket we’ve got and our only hope!
111
With Klein able to project searing sanctimony, the magma doesn’t stand a chance. I almost feel sorry for it.
30
You tax it, silly.
Either that or you can give $T to the rich people around the world by trading Eruption Certificates hedge fund.
They said it’ll work for CO2…
00
I think it is highly likely that gravitational influences due to Milankovitch Cycles and lunar precession influence this molten rock resulting in more or less heat flowing into tbe ocean, apart from the redistribution of warm ocean water. The lunar pull on the earth alone can vary by up to 47% due to changes in precession. This has to influence climate. See David Dilley video at https://youtu.be/w4hbKF5-qUE
60
An additional thought – CO2 might be released from within the earth’s crust as gravitational influences open up cracks and fissures allowing trapped gases to escape.
40
Something I found out a few years ago is that the sea level is not level, even when you allow for the tidal effects. In fact the “sea level” varies by tens of meters from one part of the globe to another. This is as a result of the uneven spread of the mass of the planet resulting in different gravitational impacts. Given that these hotspots will have a density impact due to the heat differential, and also may have an impact due to the differing chemistry of the hotspots, are these hotspots related to variations in sea level?
150
I tried to find a graphic of what you are talking about but in a short time it was hard because the images are polluted with those related to CAGW. I found this gravity anomoly map, however. Also, due to deliberate tampering with data I find it increasingly difficult to trust any data relating to CAGW, not even daily temperatures.
http://earthobservatory.nasa.gov/Features/GRACE/Images/geoids_sm.jpg
80
Thanks David,
Comparing the gravitational anomaly map with deep mantle plumes there are some similarities. Most particularly there are strong positive gravity field anomalies and deep mantle plumes under Papua New Guinea, then stretching East, then curving South to the East of New Zealand.
The opposite similarities (strong negative gravity field anomalies and no deep mantle plumes) occur both South of India and in the Caribbean.
20
KM,
I think it also depends on the type of material in the mantle.
I’m no geologist, but I vaguely remember reading somewhere that basaltic magma has different density and magnetic properties from granitic magma. This might lead to different gravitational effects?
40
From what I’ve read, can not see any connection. This is worth a read.
10
I couldn’t see any mention of density in that page you linked, so went searching
http://courses.washington.edu/ess439/ESS%20439%20Lecture%203%20slides.pdf
There appears to be significant differences in density.
I large amounts, I suspect that is going to cause gravity anomalies.
Maybe.
20
Andy, that is correct. basaltic magmas are rich in iron heavy olivine. Granitic magmas are rich in silicon/potassium/calcium minerals like quartz and feldspar. Their specific gravity is less. Is Why continents ‘float’ on top of the mantle.
30
Good little video on how mass and gravity effect sea levels and how that is taken into account the way sea level is defined: https://www.youtube.com/watch?v=q65O3qA0-n4
40
And what might a gradual upward expansion of the Pacific ocean bed do to sea levels around the world.?
80
There have been numerous theories about what the crust does in the deep oceans. One of the more convincing theories is that the crust is formed at mid ocean ridges, then moves away, and gradually cools, increasing density, so, from a side-view, if that was possible, you’d see the mid oceanic crust bowing downwards as it is more dense.
With regards to subduction zones, a similar theory states that at a subduction zone, the mass of the crust which is descending, is large enough that it pulls the crust along.
With regards to regional stress maps, some of my former lecturers, and student colleagues published this work, based on analysis of “borehole breakout” orientation, which is interesting (to me, at least). an updated version has also been worked on, a summary is here
Although it’s about the crust, this collection of material on Lithospheric Dynamics by Mike Sandiford is pretty easy to read, and explains a lot. the website is not young, and although Mike has moved away from geodynamics and geology to focus on things related to AGW (featuring on ‘our’ ABC to tell us gloom and doom stories), I still have a lot of respect for him, his geological work, and the prodigious amounts of red wine he could consume on geology field trips.
30
It seems that after centuries of scientific advancement and the ability to understand large amounts of varied influences on the natural world, warmists are taking us backwards by removing numetous known influences on climate and reducing them to one single variable, CO2, which, as we all know is of no consequence anyway.
80
Steve McIntyre looks at the latest so called ocean 2K hockey stick. More incredible BS.
http://climateaudit.org/2015/09/04/the-ocean2k-hockey-stick/
60
Does anyone wonder why the center of the earth is hot? Like seriously surface of the sun hot??
The quick google explanation is that “There are three main sources of heat in the deep earth: (1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements.
Now, it atrikes me that since we have barely scratched the earths surface (only drilling 10 – 20km) we cannot put these three theories to any type of scientific test. Unless i am mistaken?
So where does this heat come from really? Why was there so much heat involved with planetary formation in the first place? How is it sustained? Are our theories correct?
80
Regarding the sun there’s the Electric Sun hypothesis which could be transferred to explaining earths heat generation, like a dynamo effect?, just thinking.
60
The interaction between the sun’s flux and cyclical patterns of power release from within earth seem connected. It seems that when the sun is quietest, is when there are more geomagnetic storms… and vice versa.
Those of us who live in the NH may have pondered the question of why we experience winter when the earth is nearest to the sun, and vice versa.
Also, since apparently the earth spends the majority of its time in an iced-over state, and we are likely exiting from the current interglacial period, what could be the mechanism for that?
I think it’s likely to be impossible to figure out how these things work if one neglects to factor in the electric sun/electric universe ideas.
I wonder if the earth is something like a rechargeable battery. Most of the time its charge is low enough (during the long glacial periods) that most of the surface is uninhabitable, or only minimally habitable. But during interglacials, its charge is increased sufficiently to warm up more of the surface and allow plants, animals, and people to thrive. Perhaps as the interglacial ends, the quieter sun fails to recharge the earth sufficiently to balance the released energy that escapes from the earth.
20
Interesting ideas there, from our known observations of atoms and molecular activity energy and heat are relevant to the activity or speed of these base elements of our existence, these ideas always seem to stir up divisions and bias amongst scientists which is good for debate but I agree that nothing should be dismissed until we fully understand what we are actually dismissing.
00
Very Good observation Sonny!
Plausible explanations perhaps. But nothing is actually known.
30
In a more honest world, scientific theories that are not testable and falsifiable would carry a disclaimer and not be presented to the world with such arrogant certainty. When did it become an admission of inadequacy for the best and brightest minds to simply say “we do not know, it is a complete mystery, so your guess is as good as mine”.
20
It is to their eternal shame that there are those who choose to use their great talents to hide truths. Truths and facts however do not cease to exist just because those with great talents have chosen to ingore them.
20
A most excellent comment indeed sir.
00
From the seabed many volcanoes spew,
Lava pillows forming islands anew,
And mixed through the gas,
Of the fast growing mass,
Is much juvenile water too.
100
Juvenile water! Brilliant!
20
This is actually interesting . One question I have is “Why are some spots hotter than others?”
The gooey bit near the middle has been churning around for quite a while. I would think it would have evened out the temperature.
20
Al Gore thinks its a few million degrees just 2km below the crust. His cluelessness is mind-boggling.
http://wattsupwiththat.com/2009/11/16/gore-has-no-clue-a-few-million-degrees-here-and-there-and-pretty-soon-were-talking-about-real-temperature/
50
From the link to berkeley.edu that Jo provides above (Full press release Berkley News), has the press release, and at the bottom of this page has a link to another paper called “Earth’s magnetic field could flip within a human lifetime”
Comparing the two maps on each press release I note —
When looking at the volcanic hotspot map, the hotspots running from Antarctica through Africa, up the Atlantic, through Western Europe and to the Arctic appears to be approximately the same route as the path taken when the magnetic flip happens.
How strange. Might be just a coincidence or something else.
50
Hmm, I guess that some of those areas they were ASSuming subduction is not happening…
30
“Very accurate numerical simulations” ie. modelling so you don’t need to do any test drills for oil that is barely a few kilometres down- no more dry oil wells pull the other one. Whereas petro-physicists know you have to assume a result to do seismic work that depends on various correlations.
20
I am afraid that I did not even understand the graphic.
What are the black circles with a green centre? Not described in the key.
Are the red bits the volcanically active areas or are they subterranean strata of increased temperature? Tomography (I think) means depiction of cuts (ie layers). Is that what the graphic is?
20
Have stood on the crater edge at Mt Yasur in Vanuatu while the ground thumps under my feet as molten gobs of lava blast upwards,
have watched molten lava on the big island of Hawaii run into the ocean.
Now I better read this above.
10
Thin hot plumes eh?
…
Oh! The super duper computer model doesn’t have the granularity to identify thin hot plumes?
Again a magnum grid calculations are unable to resolve macro and micro occurrences.
Somewhere between 20 years of seismic wave tracking and their computer model, they’ve lost the plot.
This isn’t a CT scan, it is an imaginary scan.
40
At the very least this large-scale blob contour image with respect to PT would presume its convection (T mapping), but is not consistent with the mechanism and mechanics PT proposes. Oh well, let’s move the goal posts a bit, or better still, lets ignore it – that’s a good one.
Maybe the seismic velocity variation isn’t recording T at all (otherwise it would correspond with the geothermal data geographically, and it’s not even close), for that is simply the implicit presumption made by tomographers, or rather, the interpreters of tomography. Well, if it’s T, or Delta T in action, then why is it in totally the wrong places for where the PT mechanism requires it to be?
Oh noes! you can’t call the mechanism into question! That’s sacrosanct!
But data isn’t? Logic isn’t?
A more reasonable working presumption would be to say the seismic variation tomography inferred is not necessarily a singular measure of T variability, as assumed. Something else can produce it. But geology will stick with the standard meme, as pope-ish persons in the upper towers of the discipline will wail, “Yee must believe or be damned!”
Well I don’t, and I’m not. And it’s not even my problem. Their data does not fit their mechanism. That’s a real problem.
Joe, if you want data on heat flow input you need to look at surface geotherm maps and their correlations with topo, geo structures, and gravity anomalies, as tomography is practically incoherent for that purpose.
20
The first thing that struck me was the nice big hot spot in the belt where El Nino forms.
………
The second thing that struck me was the nice big hot spot in the belt where the gulf stream starts off the coast of Africa.
Simplified for the kiddies:
https://web.archive.org/web/20051119165345/http://www.uwsp.edu/geo/faculty/ritter/images/maps/ocean_currents.jpg
http://oceanservice.noaa.gov/education/kits/currents/media/conveyor_slideshow/26-conveyer-belt-6s.jpg
From the NOAA page:
http://oceanservice.noaa.gov/education/kits/currents/06conveyor2.html
40
Yes, I noticed the central Pacific hot spot as well. Obviously CO2 in the atmosphere not only transmits heat to the bottom of the ocean, but right down through the mantle to outer core.
But using low-energy light bulbs will soon stop that.
10
Yes, I noticed the central Pacific hot spot as well. Obviously CO2 in the atmosphere not only transmits heat to the bottom of the ocean, but right down through the mantle to outer core.
But using low-energy light bulbs will soon stop that.
10
How did that happen?
00
In school they taught us that G is the gravitational constant …but did you know that NASA JPL recently found that it cycles with half the period of Jupiter’s orbit? And did you know that the terrestrial interhemispheric heat engine just so happens to alias a 208 year cycle? Ignorance can be difficult to overcome.
I’ve put forth a very serious challenge:
https://tallbloke.wordpress.com/2015/06/11/atmospheric-convection-what-does-it-mean/comment-page-5/#comment-106912
Dare to face observation.
What you were taught in school may have been wrong…
00
E.M.smith the Chiefio has a new take on this stuff, rather interesting. New measurements of the temperature in the Earths core show it as hot as the surface of the sun. He is postulating with figures that the Earth is heated from within and the sun modulates how much heat leaves the Earth. That would easily explain a quite sun and a L.I.A.
01
[…] Mapping hot deep columns of molten rock in the top 3000km thick layer Share this:TwitterFacebookPrintPinterestGoogleEmailLinkedInLike this:Like Loading… […]
00
I think this is not an original result. An April 2001 paper in Nature, by different authors, said much the same thing. Paywalled, but here’s an article about it titled “The Four Pistons of Earth”.
http://www.spacedaily.com/news/earth-magnetic-01c.html
And a quote: “In effect, we have found that the solid Earth is being churned by a four-piston heat engine with two immense sinking cold slabs and two equally large rising hot plumes.”
20
I got this comment from geologyjim, when referencing this page, on https://notalotofpeopleknowthat.wordpress.com/2015/09/09/arctic-summer-sea-ice-trends/ site.
The link geologyjim supplies is most interesting.
10