On earthquakes, and other weighty matters...

As I was driving in to work (through the sewer) this morning just before the 0800 Morning Report news, Kim Hill (temporarily running the studio end until the Christchurch earthquake is passed by some greater event) was doing the “next hour” promos. These included an interview with a gent who puts the cause of the earthquake down to “rogue seismic waves” apparently. There is another very learned gent who puts the cause down to the gravitational effect of the moon. He was interviewed by John Campbell (no, I was watching netball at that time I think) who promptly got himself into trouble by "getting his personal opinion between the interview and the audience".

Now I am not about to critique the reasoning behind either of these theories; I know little to nothing of the rationale behind them. But the thought came to me that perhaps I should put onto (virtual) paper the probligo theory of the cause of the Christchurch earthquakes. I can present the theory with as much justification as either of the other two. Who knows? The ol' probligo could end up being interviewed on national tv!!! What a HOOT!!

Now, my caveat. I am a long-worn retiring accountant. My knowledge of seismic events would perhaps cover a reasonable sized postage stamp (do they still exist?). I know the difference between an up-thrust and a slip. I also confess that the last time I did three dimensional mechanics was about 45 years ago, and then for a period or two in a week.


The probligo theory of Christchurch earthquakes.

Recall that the first earthquakes were under Darfield, about 30km southwest of Christchurch.

Roughly, the geology of that area is continental rock underlying a broad expanse of alluvial plain, eroded from the Southern Alps. That underlying rock level is general fairly level though it is subject to increasing deformation toward the west. It forms a basin in which there is a considerable artesian water resource. The floor is not in one piece, but broken by more faults than I suspect the experts know about.

Principle 1 – Equilibrium

The theory is based upon the idea of equilibrium. The various pieces of the rock floor under the Plains are held in place horizontally by each other, and vertically by pressure from beneath countered by the mass of what is above. As the upper layers – the alluvial deposits – are comparatively fluid (compared with solid rock they are) it is a bit like a saucer of milk except that it is floating in a bigger bowl of golden syrup. To add to the picture, the saucer is not in one piece. It is fractured into a lot of smaller pieces. Those are being held in place by a flexible wall around the outside of the saucer. That is sufficient to prevent the saucer (which is somewhat denser than the underlying syrup) from leaking from beneath and sinking. A very good description of the geology can be found here.

That whole system is in an equilibrium. The saucer is replenished as quickly as the milk can leak out of the saucer. The total mass of the overlying deposits (the milk) is relatively constant.

Principle 2 – Cause of loss of Equilibrium

Land use in Canterbury has changed considerably over the past five years or so. Large areas have converted from low-intensity arable, beef and sheep farming to high-intensity dairying.

One of the consequences of that change is the very high increase in demand for water. Dairying is a high water use industry; the water content of the milk has to come from somewhere in addition to the normal by-products.

I have not found comparative statistics of the volumes of water drawn off each year over a longer period of time. Nor have I found the far more critical statitics in the change in artesian “head” in the various parts of the Canterbury area. The article I referenced earlier quoted costs in pounds rather than dollars, and mentioned a head of 9 feet in an artesian source 200 feet below surface. I interpret that to mean that water out of that bore was reaching 9 feet above ground level without pumping. The kind of detail I need is what height that bore runs to now. That number might give a clue as to the amount of water drawn from the aquifer and not replaced.

Why is this important? For the simple reason that a very good part of the mass above that saucer is (at least was) water. Draw that water off, reduce the mass holding the system in equilibrium, and the system then will try find a new equilibrium.

Principle 3 – “Local” and “area” effects of changes in the mass equilibrium.

Let us assume for the purposes of this exercise that 200 feet artesian layer covered the area between northeast Christchurch and Darfield. If I can assume that the 9 feet head has reduced to zero (3m loss) over the area of a 30km diameter circle, that could indicate the loss of something like 2 billion m3 (Pi * 15000*15000*3) of water, which unless the Blenheimers has really taken hold still represents 2 billion tonnes less of water holding that saucer together.

The question is whether that kind of regional (over a 30km circle) effect could have a local effect like the movement of two pieces of the saucer near Darfield. I believe that is a distinct possibility.

Further, once that initial movement has taken place the neighbouring pieces then have to readjust to form (hopefully) a new equilibrium.

Conclusion.

So there you have it. The probligo theory of what caused the Canterbury earthquakes. Too many cows drinking too much water and eating too much grass irrigated by too much water… Well, you gotta admit, it is just about as reasonable as George Gair (bless his cotton socks) suggesting a cow fart tax to alleviate global warming.

The Student Army

Get the title of "The Student Army" in your ears and what does it conjure? In my mind flickers of Tim Shadbolt, Helen Clark, the many many others at Auckland U in the early 1970's demonstarting (usually at the drop of a hat), drinking to excess (well, nothing has changed there), capping parades...

Here is a totally different picture for you...

From Grany Herald -

First, the power of nature. Now the power of Facebook.

Students are using their social networking skills to pull together a volunteer army of more than 1300 to help out the shaken Christchurch community.

An entrepreneurial Canterbury University student created a Facebook event page that brought 300 students, carrying shovels and wearing gumboots, on to the streets of Halswell and Hoon Hay ready to help affected residents yesterday.

The event page, Student Volunteer Base for Earthquake Clean Up, has 1356 people willing to help and the number is climbing rapidly as 5000 invitations are awaiting students to reply.

University student Sam Johnson created the Facebook page to gather the support of students during their extra week of holidays.

"We have a spare week to do some good for the community. It's the perfect opportunity to come out and do something decent," he said.

The event page reads: "Basically what needs to be done is door-knocking in teams and offering to help clear properties. Wheelbarrows, shovels, gumboots, yardbrooms ... hunt them out!"

Mr Johnson, 21, said he got the idea from other Facebook events created after the quake.

Hoon Hay resident Ellen Cooper said what the students were doing for the community was heartening.

"If anyone has never had faith in young people, well, now they should."

She said the students knocked on her door and asked if they could "do any hard labour".

Christchurch City Council gave the students a priority list of the most damaged areas.

TV news last night showed a group of about 30 digging silt from a major road and clearing the channelling on each side. From the wide views it looked like they had cleared some 200m of 4 lane street, judging by the piles of silt along the roadside. Now that is considerable effort seeing they are using shovels and wheelbarrows.

Another group (different area?) was digging out private driveways and access.


More power to their arms.

Oh, Canterbury...

Pick any of the major news outlets - TVNZ, TV3, nzherald, even yahoo.com.au or just google "christchurch"

I have tears in my eyes, an ache in my heart.

Canterbury, what can we do?

In all of the raruraru about Egypt...

This is THE best article I have seen on the people behind the popular uprising that led to Mubarack resigning.

Early in 2008, workers at a government-owned textile factory in the Egyptian mill town of El-Mahalla el-Kubra announced that they were going on strike on the first Sunday in April to protest high food prices and low wages. They caught the attention of a group of tech-savvy young people an hour's drive to the south in the capital city of Cairo, who started a Facebook group to organize protests and strikes on April 6 throughout Egypt in solidarity with the mill workers. To their shock, the page quickly acquired some 70,000 followers.

But what worked so smoothly online proved much more difficult on the street. Police occupied the factory in Mahalla and headed off the strike. The demonstrations there turned violent: Protesters set fire to buildings, and police started shooting, killing at least two people. The solidarity protests around Egypt, meanwhile, fizzled out, in most places blocked by police. The Facebook organizers had never agreed on tactics, whether Egyptians should stay home or fill the streets in protest. People knew they wanted to do something. But no one had a clear idea of what that something was.

The botched April 6 protests, the leaders realized in their aftermath, had been an object lesson in the limits of social networking as a tool of democratic revolution. Facebook could bring together tens of thousands of sympathizers online, but it couldn't organize them once they logged off. It was a useful communication tool to call people to -- well, to what? The April 6 leaders did not know the answer to this question. So they decided to learn from others who did. In the summer of 2009, Mohamed Adel, a 20-year-old blogger and April 6 activist, went to Belgrade, Serbia.

(I bolded that bit as a teaser.)

I will not c&p the rest of it - as strong as the temptation might be. It is a detailed piece of power writing.

And, I suspect, it highlights why the orthodox "great powers" have come to grief in their attempts to introduce democracy to...[name the country of your choice].

Read it, think about it. It is one of the best I have read in a very long time.

A quick visit to the past...

Isn't it curious to revisit blog posts like this one, five years after the event?

The news this week - best summary I have found comes from the Guardian...

The defector who convinced the White House that Iraq had a secret biological weapons programme has admitted for the first time that he lied about his story, then watched in shock as it was used to justify the war.

Rafid Ahmed Alwan al-Janabi, codenamed Curveball by German and American intelligence officials who dealt with his claims, has told the Guardian that he fabricated tales of mobile bioweapons trucks and clandestine factories in an attempt to bring down the Saddam Hussein regime, from which he had fled in 1995.

"Maybe I was right, maybe I was not right," he said. "They gave me this chance. I had the chance to fabricate something to topple the regime. I and my sons are proud of that and we are proud that we were the reason to give Iraq the margin of democracy."

The admission comes just after the eighth anniversary of Colin Powell's speech to the United Nations in which the then-US secretary of state relied heavily on lies that Janabi had told the German secret service, the BND. It also follows the release of former defence secretary Donald Rumsfeld's memoirs, in which he admitted Iraq had no weapons of mass destruction programme.

I remember the news video of that speech well. I recall posting that I had the strong impression Powell was speaking with at least one of his minders (Cheyney? Rumsfeld?) "holding a gun" to his side.

Be that as it may, I hope that Mr Janabi has been able to comfort his conscience with the 20 talents of silver... sorry, German citizenship and Mercedes Benz car that he was given for his story.

More important, take the time to go back and re-read the commentary from the link I gave at the beginning. That was the beginning of the legacy he created.