A sesimic image of the whole Earth

[EnumaElish]

Kiss the Mediterranean goodbye. Ditto the Red Sea and its wonderland of coral reefs and exotic sea life. And prepare for the day when San Francisco has a gritty new suburb: Los Angeles. Indeed, much of Southern California, including the Baja Peninsula, will eventually migrate up the west coast to make Alaska even more gargantuan...

...Dr. Scotese drew a series of futuristic maps and, in the 1990s, found an ideal way to communicate his increasingly detailed visions of the terrestrial past and future: over the Internet. Today, Dr. Scotese’s Web site, www.scotese.com, which he started in 1998, showcases his work, called the Paleomap Project. Teachers use his animations, and his site has won scientific awards.

(From New York Times: Science)

 

[zankaon]

It's not a coincidence that the plasticity and adaptivity we call life evolved on a geological active planet. If there were no latter, then no liquid outer core, and no dynamo effect with protective magnetosphere, which shields us from the solar wind. Such unimpeded wind would erode away the atmosphere and then the oceans. The fault resides not with nature, but with our overwhelming successful agriculture, resulting in a hugh population. Nature's Maltusian ways will ensue if we are not more careful. A hugh population is more vulnerable to natural disasters. Urbanization and education are negative feedbacks on demographics. Such geological and biological evolution has been with us for a very long time.
http://en.wikipedia.org/wiki/Geologic_time_scale"
It would be highly improbable for it to end soon. Once life takes hold on a geologically active planet (even perhaps for an ice covered rogue planet) http://en.wikipedia.org/wiki/Rogue_planet" ,
it would seem probable to be quite robust to perturbation.

 

[billiards]

Has this been done?

I've seen tomographically derived "velocity models" of the Earth before. These can show features, such as anomalously fast slabs under continents (subducting plates) and anomalously slow blobs beneath hot spots (mantle plumes). But has anybody ever imaged the Earth with actual seismic data before?

I guess what I mean would be something like this: http://images.google.com/imgres?img...en&safe=off&rls=com.microsoft:*:IE-SearchBox"
But not just of the crust, but the whole Earth!

 

[Xnn]

A published http://www.pnas.org/content/106/44/18443.abstract" has found that recent changes in the climate of Baffin Island are unique over the past 200,000 years. This is notable because between 119 to 124 Kyears ago, the global climate was thought to be about 2C warmer than our current climate with sea levels approximately 7 meters higher. However, that past warming was driven by changes in the Earths orbit which resulted in the area near Baffin Island receiving significantly more sunshine during the summer. Most of the Greenland Ice sheet had also melted during that time. So, ice cores from Greenland are not fully intact further back in time than about 120K years ago which is sometimes referred to as Marine Isotope Stage 5E.

Ordinarily we would also expect a long term cooling trend to be currently occurring near Baffin Island. This is because the Earth's orbit has been gradually reducing the amount of summer sunshine in the Arctic for the past 8,000 years and this trend is expected to continue for another 4,000 years. However, this study is "clear evidence for warming in one of the most remote places on Earth at a time when the Arctic should be cooling because of natural processes."

Here's a http://www.colorado.edu/news/r/fa189a8186a324d8f62b5d55ba4b8969.html" to the press release and a quote:

The sediment cores were extracted from the bottom of a roughly 100-acre, 30-foot-deep lake near the village of Clyde River on the east coast of Baffin Island, which is several hundred miles west of Greenland. The lake sediment cores go back in time 80,000 years beyond the oldest reliable ice cores from Greenland and capture the environmental conditions of two previous ice ages and three interglacial periods.

The sediment cores showed that several types of mosquito-like midges that flourish in very cold climates have been abundant at the lake for the past several thousand years. But the cold-adapted midge species abruptly began declining in about 1950, matching their lowest abundances of the last 200,000 years. Two of the midge species adapted to the coldest temperatures have completely disappeared from the lake region, said Axford.

In addition, a species of diatom, a lake algae that was relatively rare at the site before the 20th century, has undergone unprecedented increases in recent decades, possibly in response to declining ice cover on the Baffin Island lake.

"Our results show that the human footprint is overpowering long-standing natural processes even in remote Arctic regions," said co-author John Smol of Queen's University. "This historical record shows that we are dramatically affecting the ecosystems on which we depend."

 

[apeiron]

Yes I live in Christchurch under the bit that hasn't been broken. But check the map and you can see that our story could be one of a large lateral fault in the middle of its creation.

At first I could believe this was unlikely (having good access to local scientists who know the geology). The story was the original quake was an existing mag 7 faultine buried under some 20k years of alluvial gravel. But recently it has become suggested it was instead four lesser cracks becoming lined up.

And now we have had a 6.3 very shallow fault that looks like an extension of the previous line of stress. And in turn, that there is a further big chunk of potential fault inbetween now waiting to go. A line that in fact runs through my house along with the rest of the unbroken part of town.

So any experts out there want to look at the maps and hazard some opinions?

It is already accepted here that smaller lateral faults to the Alpine fault are assembling into larger ones all down the east coast of New Zealand. There are a bunch of about seven (including the Hope, Awatere, etc) running from Wellington down to Kaikoura, and one known to be assembling at the southern end. Christchurch would now be the same happening even further south. And perhaps wanting to complete the job in six months, six years, who knows?

Check this geonet map to see early view of where the Christchurch faults lie.
http://www.geonet.org.nz/earthquake/quakes/recent_quakes.html

Here is the story on the laterals further north.
http://en.wikipedia.org/wiki/Marlborough_Fault_System

And then this comment from our top earthquake guru, Kelvin Berryman, just yesterday about the new questions.

Berryman said the faults associated with the September 4 and February 22 quakes were separated by what may be at least two more hidden faults underneath Christchurch.

Aftershock patterns suggested at least two north-east-south-west trending faults lay between the east-west Greendale Fault exposed at the surface in September last year and the fault under the Port Hills.

Scientists originally thought there had been 17km of subsurface rupture between Halswell and Taylors Mistake. However, that had been refined to movement over an 8km-wide and 8km-long area.

"It's not a big fault. It hasn't had a lot of movement on it in the past. "The quake occurred at the periphery of the September 4 aftershock cloud. "The stress front has arrived there and found a piece of the crust that was primed and ready to go."There was no indication how long it was since the Port Hills fault last moved, Berryman said.

"It has not been determined before now in any geological maps or geophysics work. "It could have moved before, but it might be the first time it ruptured in the last 100 million years," Berryman said.

http://www.stuff.co.nz/national/chr...-a-metre-taller-after-Christchurch-earthquake

 

[Astronuc]

Primordial Gases Deep in Earth May Reveal How Planet Formed

http://news.yahoo.com/primordial-gases-deep-earth-may-reveal-planet-formed-114003576.html

Mark Kendrick, an Earth scientist at the University of Melbourne in Australia, and colleagues collected serpentine rocks that had one been in the mantle, under the crust, but were uplifted where tectonic plates had collided.

Kendrick studies noble gas and halogen geochemistry of crustal fluid and Ar-Ar geochronology. Mark Kendrick is a QEII research fellow at the University of Melbourne School of Earth Science. His work uses noble gas isotopes and halogens to investigate the role of fluids in the Earth's crust and mantle. His current projects are focused on testing the extent to which these elements are recycled from the atmosphere and ocean into the mantle by tectonic processes operating at convergent plate margins. However, using noble gases and halogens as fluid tracers to investigate the origin of fluids in economic mineral deposits including the role of abiogenic methane in gold deposits remains an area of special interest.

http://theconversation.edu.au/profiles/mark-kendrick-4508


Salty water and gas sucked into Earth interior helps unravel planetary evolution
http://newsroom.melbourne.edu/news/n-636

Noble gas and halogen evidence on the origin of IOCG mineralising fluids (2008)
http://www.cprm.gov.br/33IGC/1338068.html

 

[Ophiolite]

The issue is well summarised by Miller in this recent note in PNAS.

"Recent workers aiming to assess histories of eruptible magma and consider consequences for eruption hazards tend to fall into two camps, as described in Barboni et al. (1). In the first camp are the “cold storage” advocates, who suggest that magmatic materials are crystal-rich and ineruptible, perhaps even subsolidus, throughout most of their history, but that they become briefly eruptible as a result of thermal rejuvenation.
.
The second camp is composed of those who favor “warm storage” and estimate that during much and perhaps most of >105 y magma system histories eruptible magma is stored beneath volcanoes."
.
It remains to be seen whether the cold storage or warm storage view has greater validity; perhaps more likely, different systems have different storage styles, or the reality of typical magma system behavior incorporates elements of both."

In the same issue of PNAS the case for warm storage is made by Barboni et al who say " The increasingly popular notion that steady-state magma chambers are highly crystallized, and thus only capable of erupting during brief (<1 ka) reheatings, implies that melt detection beneath volcanoes warns of imminent eruption...we show that arc magmas may generally be stored warm (are able to erupt for >100 ka). Thus geophysical detection of melt beneath volcanoes represents the normal state of magma storage and holds little potential as an indicator of volcanic hazard."

If cold storage were the only, or the predominant mechanism, then detection of melt beneath a dormant volcano provides advance warning of potential eruption. One would expect that as our detectors become more sensitive, our software more sophisticated, our grasp of the mechanisms acting within magma chambers more refined, that it will be possible to predict eruptions with a high degree of accuracy. At present we are far removed from this.