olelog

The Romanian Cutremur.net has a nice figure showing the detached slab beneath Vrancea at
http://www.cutremur.net/modelul-cel-mai-larg-acceptat-pentru-zona-vrancea/
(Cutremur is Romanian for earthquake).
The slab is shown in light blue (marked as oceanic lithosphere).

This is a continuation of my post on the Vrancea earthquake Saturday 25 April 2009.

This is a continuation of my posts here and here.
(After this I'll return to my more usual themes)

1. Here are the main results of the recent donor conference for Somalia held in Brussels:
* International donors raised 165 million euros to help bolster Somalia's security forces and back an African peacekeeping force
* The European Commission contributed almost half (72 million euros)
* Sixty million euros will go to the AMISOM African peacekeeping mission, which numbers around 4300 troops, short of its 8000 troop target
* Twelve million euros will go to help build up the police force (including coast guard)

2. As a positive note I gather some of the money will create jobs in Somalia, but wonder about the rest, seen that the present Somali government hardly rules over more than most of the capital, Mogadishu, and that the radical Islamist al-Shabab group, which has links to al-Qaeda, operates freely in much of the capital, Mogadishu, and most of south and central areas of the country (while the northern Somaliland and Puntland act more or less as independent states). I am also worried because Somalia's transitional federal parliament has unanimously backed the introduction of Islamic Sharia law in the country after a vote over the issue was brought to parliamentarians last Saturday. The Islamist opposition leader Sheikh Hassan Dahir Aweys, who has just returned to the country after exile in Eritrea, has blankly called for African Union troops to leave Somalia before he talks to the government. Somalia does indeed look like a failed state beyond help.

3. Here are a few things said at the conference: Piracy is a symptom of anarchy and insecurity on the ground. More security on the ground will make less piracy on the seas. The cause of piracy is the poverty, the fact that the young fishermen have no perspective. The piracy attacks are a symptom of the lack of security. The restoration of peace and stability to Somalia is the only way to solve these problems. I agree to all of that, but ...

4.A future donors' conference is planned to raise funding for continued humanitarian and reconstruction assistance to Somalia.

5.Seen the situation it is impossible to get exact figures. A current estimate (for Somalia as a whole) is 9 million inhabitants of which 3.5 millions depend on food aid to survive. More than one million people have been made homeless by fighting in the past two years.

6.I don’t think that the present situation is Inch'Allah - let us instead pray for common sense, peace, and stability.

• http://www.radioalgoa.com/newsarticle.asp?NewsID=147140
• http://news.bbc.co.uk/2/hi/africa/8014212.stm
• http://www.google.com/hostednews/ap/article/ALeqM5jdZmEqPLeCk_Ib-BS13v4Cpl_B9QD97O5TQO0
• http://geography.howstuffworks.com/africa/geography-of-somalia.htm
• http://news.bbc.co.uk/2/hi/europe/8014902.stm
• http://news.bbc.co.uk/2/hi/africa/8016985.stm
• http://edition.cnn.com/2009/WORLD/africa/04/18/somalia.sharia/index.html?iref=24hours
• http://www.radionetherlands.nl/currentaffairs/region/europe/090424-somalia-donors-EU

Climate, Wars, Economics, and Pirates

First let us get things straight. Human beings lived in Africa long before Europe was populated. In other words the history of Africa didn’t start with the European colonisation of Africa. Neither is culture a European monopoly.

From the 25th century BC and onwards the Egyptians sent expeditions to the land of Punt, which is supposed to have been the Horn of Africa. If so a lot of things have changed since then, as the Land of Punt was known for producing and exporting gold, aromatic resins, African blackwood, ebony, ivory, slaves and wild animals.

Somalia became independent in 1960. It has been tormented by crude civil war most of the time since 1986. UN humanitarian troops landed in 1993 and started a two-year effort (primarily in the south) to alleviate famine conditions. The period of 1998–2006 saw the declaration of a number of self-declared autonomous states within Somalia. In January 2009, Ethiopian troops withdrew from Somalia following a two year insurgency. In short their is practical no law and order and the central Somalian government has little to say.

Today 85% of the population are Somalis, a population that CIA estimates at nearly 10 million people (another source says 4 million in 1979). The Somalis began populating the area around 1000 years ago. About 70 percent of all Somalis are nomads who travel with their herds through Somalia, Kenya, and Ethiopia. Today more than 3 million Somalis are dependant on food aid and 1.3 million are fugitives.

Only 1.64% of Somalia’s 637 657 km² is arable land with permanent crops on 0.04% of Somalia. Most of the country receives less than 500 millimeters of rain annually, and a large area encompassing the northeast and much of northern Somalia receives as little as 50 to 150 millimeters. One of the country’s biggest problem is the heavy loss of livestock suffered by the pastoralist communities in the worst drought in 30 years.

Somali has a 3,025 km long coastline. In 2005 ca. 700 foreign fishing trawlers were illegally active in Somalian waters. For years other countries have dumped nuclear and toxic waste off the coast of Somalia. After the tsunami in 2005 some of this waste washed ashore with disastrous results for the coastal population like skin diseases and mouth bleedings.

So what can you do in Somalia for a living. Crops gone, livestock gone, fish gone, and no social security. One solution is taking aid helpers as hostages to get ransom money. It has been done lately. There is however bigger money in piracy. And the pirates are local heroes. They are the revengers of those foreigners that destroyed the fishing industry and they provide money.

Eyl in Puntland is the location of most of Somalia's casualties from the 2004 Indian Ocean Tsunami. It has about 3 million inhabitants and has become something like the capital of the Somalian pirates. As the so-called pirate capital it is where the high seas hijackers often steer their captured vessels. Special restaurants in the town cater for the captive crews. With their expensive tastes in fancy houses, cars and women, the pirates have brought boom times to the local economy. The Puntland government has acknowledged that they are relatively powerless to stop pirate activities.

To recapitulate: Somalia is one of the poorest, most violent, least stable countries anywhere on Earth. It suffers from severe drought and its people face hunger and violence on a daily basis.

How can you stop the piracy. Much is said these days about warships and other military or paramilitary actions. No doubt such things are necessary. But without improving the humanitarian situation for all Somalis, the problem will not be solved. This is an extremely difficult task for the international community.

I wonder if the international conference held these days in Brussels, and sponsored by the United Nations and the European Union, that aims to raise at least euro128 million ($166 million) in donations for Somalia's nascent security forces and for the African Union peacekeeping contingent there, leads to any decisive results.

• http://www.time.com/time/world/article/0,8599,1892376,00.html
• http://www.latimes.com/news/nationworld/world/la-fg-somalia-pirates15-2009apr15,0,165660.story

See also my post: http://my.opera.com/nielsol/blog/2009/04/20/floods-in-somaliland

I must admit that at my first glance I skipped the following title in the newest issue of Science as of no interest: Anomalous Fractionations of Sulfur Isotopes During Thermochemical Sulfate Reduction. So what? Just to say how difficult it may be to see what hides behind that sort of titles. If the title had included the words “Great Oxidation Event”, I might have woken up earlier.

Now I have read the paper (in full). There is a lot of chemistry in it, and it is all about laboratory experiments, so it is indeed no read for lesser mortals. If, however, we call the aforementioned ‘fractionations’ MIF (if you really want to know “MIF” is short for "mass-independent fractionation", otherwise just forget it), and state that MIF are present in many sedimentary rocks older than 2.4 billion years, but are virtually absent in younger rocks, even I begin to get slightly more interested. Reading the editor Richard Kerr’s comments here and here helped poor me quite a lot further.

What we are discussing is in fact the “Great Oxidation Event”. Oxygen has not always been as abundant in the atmosphere as it is today. Most scientists believe that for half of Earth's 4.6-billion-year history, the atmosphere contained almost no oxygen. We and other animals need oxygen (to breathe). You cannot evolve animals like us without having a significant amount of oxygen. Without the Great Oxidation Event, we would not be here. No dinosaurs, no fish, no snakes, no monkeys or donkeys - just a lot of microorganisms. Based on sulphur isotopes (MIF, if you like) that oxidation event was dated at 2.4 billion years ago. As far as anyone knew MIF could have happened only under solar ultraviolet radiation in an oxygen-free atmosphere The new laboratory results reported in Science mean that this is not necessarily so, but in fact they challenge such a relatively late arrival of this "Great Oxidation Event."

The paper suggests that the newly discovered chemical reactions reopen the question of early oxygenation. If an oxygen-free atmosphere is not the sole source of MIF sulphur after all, it is possible that oxygen was present in the atmosphere before the MIF signal disappeared. The sulphur isotope record of sedimentary rocks may well be linked to the biological evolution of Earth, but perhaps in ways different than previously thought.

So, how early was oxygen's rise? - 3.5 billion years ago? 2.7 billion years ago? 2.4 billion years ago? There is evidence that oxygen levels also rose 1.3 billion years ago and again before the Cambrian Explosion, a rapid proliferation of animal life that began 540 million years ago. Some researchers believe increasing levels of atmospheric oxygen helped trigger the Cambrian Explosion. A couple of weeks ago I also posted about the Great Ordovician Biodiversification Event that started around 470 million years ago.

Anyway, the current idea of an early oxygen-free atmosphere (before 2.4 billion years ago) will probably still reign for some time to come.

Reference:
Anomalous Fractionations of Sulfur Isotopes During Thermochemical Sulfate Reduction
Yumiko Watanabe, James Farquhar, and Hiroshi Ohmoto (17 April 2009)
Science 324 (5925), 370. DOI: 10.1126/science.1169289.

• http://www.sciencemag.org/cgi/content/abstract/324/5925/370
• http://sciencenow.sciencemag.org/cgi/content/full/2009/416/1?rss=1
• http://www.sciencemag.org/cgi/content/summary/324/5925/321a
• http://www.astrobio.net/news/article541.html
• http://www.redorbit.com/news/science/1672551/origins_of_sulfur_in_rocks_tells_early_oxygen_story/index.html?source=r_science
• http://www.geologytimes.com/research/Origins_of_sulfur_in_rocks_tells_early_oxygen_story.asp

More technical note:
Chemical elements often have more than one form. While the number of protons and electrons are all the same, the element may have forms with a greater or lesser number of neutrons and consequently a different atomic weight. Sulphur has four naturally occurring isotopes none of which are radioactive (isotopes that are not radioactive are called stable isotopes). Although 95 percent of sulphur has an atomic weight of 32, the other 5 percent is composed of sulphur with atomic weights of 33, 34 or 36. The relationship between the amounts of 33, 34 and 36 are predictable based on the differences in their weights, but in the early sedimentary rocks examined, the relationship was often anomalous. Mass-independent fractionation (MIF) refers to any chemical or physical process that acts to separate isotopes, where the amount of separation does not scale in proportion with the difference in the masses of the isotopes. Mass-independent fractionation processes are less common than other sorts of isotopic fractionations, and they occur mainly in photochemical (and spin-forbidden) reactions. Observation of mass-independently fractionated materials can therefore be used to trace these types of reactions in nature and in laboratory experiments. It has been argued that sulphur-bearing minerals in sedimentary rocks older than 2.4 billion years formed from native sulphur (S) and/or sulphate (SO₄^2–: S⁶⁺) produced by ultraviolet (UV) photolysis of volcanic sulphur dioxide (SO₂) in an oxygen poor atmosphere, and thus that the record of anomalously fractionated S isotopes is evidence for the transition from an anoxic to oxic atmosphere about 2.4 billion years ago.

Could decomposition of dead cyanobacteria (blue green algae) be involved in the production of anomalous sulphur isotope relationships?

As plate tectonics are the cause of most earthquakes, it is no wonder that those earthquakes tell us a lot about plate tectonics. Sometimes, however, it takes a long time to read the message.

Two years ago I wrote a minor post about Solomon earthquakes that occurred in April 2007. In the meantime these earthquakes have been thoroughly studied, and a paper on some of the findings has just been published in the journal Science. The earthquake is sort of special, a.o. because it occurred at a three-plate boundary, or triple junction. Below is a simple situation map.


The New Georgia Island Group of the Solomon Islands is one of four places where an active or recently active spreading ridge has subducted beneath an island arc. The spreading ridge pushing the small Solomon Sea Plate and the Australian Plate apart is being subducted beneath the Pacific Plate. The situation is rather complicated because the two plates descend beneath the overriding plate at different rates and directions.

According to the study the event began in the Australian Plate and moved across into the Solomon Sea Plate and had two centers of energy separated by lower energy areas, which is noticeable as we normally think earthquakes should stop at the plate boundaries. When the earthquake moved from one plate to the other, it quickly changed direction, mimicking the different plate motion directions of the plates involved. The authors are confident that the fault slip in the two main locations are different by 30 to 40 degrees. That behaviour during an earthquake has probably never been observed before, but it most certainly has happened here before, according to the authors.

Before about half a million years ago, the easternmost segment of the Woodlark Basin spreading ridge was subducting beneath the westernmargin of the Solomon Islands, and the ridgetrench triple junction migrated northwesterly at around 110 to 120 mm/year. The differences in plate subduction rates and directions produced a slab window, which today lies beneath the southern New Georgia Islands. (When a mid-ocean spreading ridge subducts, it typically splits apart at depth to form two tapered slab edges separated by asthenospheric mantle within an inter-slab gap called a slab window).

A cartoon in the paper shows how the Solomon Sea Plate and the Australian Plate subduct as two different layers (slabs) beneath the overriding Pacific plate, with a slab window at depth (shown as increasing empty space between the two coloured slabs). The surface subduction boundary is marked by a red line.




• http://www.sciencemag.org/cgi/content/short/324/5924/226
• http://news.yahoo.com/s/ap/20090409/ap_on_sc/sci_solomon_tsunami_1
• http://www.eurekalert.org/pub_releases/2009-04/ps-sie040609.php
• http://www.geologytimes.com/research/Solomon_Islands_earthquake_sheds_light_on_enhanced_tsunami_risk.asp
• http://earthquake.usgs.gov/eqcenter/eqinthenews/2007/us2007aqbk/finite_fault.php
• http://earthquake.usgs.gov/eqcenter/eqinthenews/2007/us2007aqbk/
• http://walrus.wr.usgs.gov/tsunami/solomon07/index.html