The recent events of Christchurch and surrounding areas have been unforeseen by those in the know obviously for some time, until the 7.1 quake in September. But this quake happened a fair distance away from Christchurch and was linked to an alpine fault.
The real shocker, for scientists and citizens was the February quake of 6.3 centered near Lyttelton. This quake, like it's predecessor, was shallow and very damaging (loss of life is always damaging) but to the scientists amazement happened in an area not seen as a possible fault line. But should they have been amazed? Should they have in fact done their homework and seen that like most geothermally active areas, earthquake fault lines are bound to be evident.
Yes, geothermically active. Ok, the twin volcanic cones of Lyttelton harbour and Akaroa Harbour have been inactive for many thousands of years, but it's fair to say earthquakes in the area may have been prevalent throughout history. No, not recent history of European occupation, throughout the time the volcanoes became inactive. Let's not forget, this Christchurch area is geothermically active with Hamner Springs not far away, tectonic plate action throughout the whole Canterbury area, and as illuminated, ancient volcanoes. It all points to a fact that with the existence of volcanoes, there is plate action as volcanoes are effectively plate pressure valves.
I applaud the governments decision to rebuild Christchurch, and the resilience of the people of Christchurch and Lyttelton, but I have this nagging thought that the earthquake sequence is not going to end in the short term. In fact, crystal ball gazing I see a deserted city, especially if it shaken up by two more 6 and above quakes. People can only stand so much, and the real risk is that more people could die if they remained in the area, a very real risk. Remember, the 7.1 did some damage and no loss of life, the weaker 6.3 killed 180 plus people and did severe damage. The more recent 5.5 and 6.3 only compounded the problem.
I suppose we should also celebrate uniqueness. How many modern earthquakes (since records began) have had a series of very strong aftershocks that did more damage than the original? Physically, socially, and mentally?
New Zealand, wake up to the fact that many people from Christchurch might want to become your neighbours, move their businesses to towns or cities away from a nil customer base, and generally want in their own minds to be safe for themselves, their elderly, and their children. The one guarantee is that humans will adapt and change, there is no guarantee the Christchurch earthquakes will stop in the short term. Open your arms and welcome them to their new homes.
28/5/2017 editted to add - I suppose I'm a quack - Kaikoura Quake attests to my summations.
hmm - yeah but with every big quake aftershocks come and go for about 2 years then it is quiet again.
ReplyDeleteI come from westport originally - Murchison earthquake happened qwhen my dad was 13 and had aftershocks - then Inangahua when I was 11 - I remember aftershocks then difference is that Westport has such a small population - but the road and train though the Buller Gorge was unable to run so Westport was more or less cut off - and a family died in Inangahua then also -
Anyhow I think that though there may be a couple more big ones people will on the whole sit it out - thats what my friends and family and eeryone I know intends to do - I have only had one friend leave the place.
The port hills fault opened up on Sept 8th The Boxing Day quake was the Port Hills fault also - Greendale has not had a big aftershock - but many small ones some still haopening if u look at the addresses of the quakes. both the Greendale fault and the Port Hills fault were not known to the scientists as they had not moved for 16000 years -- but yes I am suprised they didn't know about the Port Hills fault cos of the volcanoes -- and this latest one is another fault again.
Greendale fault is not under Chch - is in the middle of the Canterbury plains - back in the day it would have been under the ocean and the plains formed over the fault line I guess. I don't think it is connected to the Alpine fault (the one which causes the disruption on the West oast and which threatens Wellington)
I heard a scientific prediction when I was in ChCh after the Feb quake that all these new and small fault lines they were discovering would probably all move during this time - but that with every new movement the pressure is pushed East - so the next fault to move will be east of the currently moving fault. I have noticed on http://quake.crowe.co.nz/ (which gives the most detailed and up to date info) that the addresses are moving east. After Feb 22nd many of the aftershocks were in Port Levy -- now since Monday there are a whole lot of new ones at Pidgeon Bay - East of Port Levy.
What this means to me is that these quakes will move off the land into the ocean and become less devastating until eventually they settle. BUT - it also means that the pressure out West has not been released - SOOOO ..... the Alpine fault remains the earthquake risk that it was before ChCH -- and therefore Wellington is still at much of a risk of the 'big one' as it was - if people are going to move from ChCh they better not think of moving to Wgtn I reckon. Best to stay in ChCh better the devil u know and all that!
Personally I would rather not be in Wgtn for the big one - the buildings there seem less sound than the ones in ChCh were - and sooo many built on hillsides
Impressive response. Science is 90% historical and 10% certainty.
DeleteIsn't it funny how the larger shakes are always around full moon. Ken Ring might have had something there, tis a pity people shut him up, he might have had some valuable info to share.
ReplyDeleteI have a bad feeling about Chch's future, I kinda feel it will all end with a real biggin and then settle down.
Wellington in a big earthquake will crumble, it is built on rotten rock which will disintegrate. Hubby and I were relieved when we moved out of the area.
Anyone, given time and a fair smattering of commonsense could agree with Ring (and others) I have always supported the cosmic science of planets etc having gravity effects.
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