Family KiwiDutch are visiting family in Christchurch New Zealand and my Aunt and Uncle are talking about their experiences during and after the 2010 and 2011 earthquakes.
It’s amazing the things that happened (or didn’t happen) in the September, December, February and June quakes: each quake was a unique experience with unique consequences because they came from different faults and directions.
Damage varied from massive in the September quake to minimal in the later ones or in come cases visa versa.
We talk about that “zones” that houses have been labelled and what the colours mean.
A “Red zone” house or business means that either the land or the building or both are beyond repair, and the Government has descided for areas deemed Red, that trying to fix severely broken infrastructure such as water and sewerage and power over, over and over again is no longer a viable option.
Subsequently, if you are Red, the government will pay out the value of your land as per the registered valuation of 2007, your insurer should then pay for the for building and you have to take this option within two years and go and live elsewhere.
Red Zoned properties will be bulldozed and at the moment the thinking of the people of most people is that Red zoned areas will be allowed to revert back to nature… back to their undeveloped state. However, since the government has spent so much money buying out so much land, some fear that maybe five or ten years down the track, the government may be tempted to invest in wholesale land strengthening of the red zones and bring them back to a state suitable for development.
This however is a much more long term idea and one that doesn’t sit easily with any the friends and relatives I’ve spoken with. They would far rather that it be turned into a permanent nature reserve or recreational areas of some sort.
So, what caused some areas to become Red? There are a many possible answers to this question but there are several main causes.
The first is due to liquafaction. When the subterranian soils are mostly sandy and an earthquake strikes, the land literarally turns to liquid as the soil vibrates. Small fissures and tiny volcano like structures appear along with large and small cracks and the water table is forced upwards shooting out tons of silt and water through all of these new openings . Often, since the sewerage network is broken at the same moment, sewerage is mixed into the liquafaction as well.
Liquafaction can irritae skin, chokes plant growth, is a heavy soupy sludgy mass when wet and once it dries out it makes a fine corrosive dust that is easily windblown. For every centimeter of liquifaction that makes it’s way to the surface, the land benieth it will have sunk by the same amount.
Liquafaction also causes the land to settle back unevenly once the land becomes solid again, causing houses to warp, twist or break away. The second event that turned many areas Red, was Lateral Spread.
During an earthquake you have a large underground wave surging upwards towards the earths surface and it will come faster to the surface in places where ground surface resistence is lower. Riverbeds and the water above them offer very little resistance so the riverbed is quickly pushed upwards.
This causes the sides of the river to be pushed outwards and severely distorts the surrounding land as the push effect is in turn transferred onwards.
In areas around both of Christchurch’s rivers (the Avon and the Heathcote) where the soil beneith was also predominantly sandy then the combination of Lateral Spread and liquifaction caused land to sink in some neighbourhoods as much as 1.5 meters (almost 5 feet).
For many areas close to Christchurch’s Avon River, the new lower ground level meant that homes were no longer a satisfactury distance above the water table either, so flooding become an issue after every heavy rainfall and with every rainfall and the continuing aftershocks (almost 10.000 to date since Sept 2010) more liquification continued, further sinking the land.
In areas like Avonside which already had historical problems with semi-regular floods from the river during high spring and winter tides the land is now lower than the river at normal flow and libal to continue sinking.
As land damage was assessed, areas were catagorised into zones. “Red” means that land repair would be prolonged and uneconomic, ‘Orange” means that further assment is required, “Green”means that repairs or rebuilding can begin and “White” means that more mapping and assessment is needed or is still underway (broadly speaking many of the white zone areas are on or around the Port Hills, where subsidence of retaining walls and the threat of rockfalls are the perdominant factor in their zoning).
So… that’s your lesson in geotechnical engineering for the day… But what does it have to do with my photographs?
Well, our discussion about the various zones led us to the plight of the house where my grandparents lived for many many years.
It’s the house where they spent almost all of their later lives, the house with the front bedroom with the big double bed that my sister and I shared whenever we stayed overnight.
It’s here in the “best” living room next door to that bedroom where my mother and her three brother’s fessed up to all their childhood misdemeanour’s after a long day celebrating my Grandparents 50th Wedding Anniversary.
Among other things, they confessed: close shaves with dynamite, a wire bobby-trap over a bridge that claimed the local constable as it’s victim instead of the school bully who was late that day and a certain West Coast hill fire that a certain Uncle (in his childhood) lit accidently when a matches and secret cigarette combination went horribly wrong.
It might not have been so bad had Granddad not been in the local Volunteer Fire Brigade at the time.
My grandparents, my cousins, sister and I listened agast as the revelations poured out from my mother and her brothers and for every gasp of near disaster there were also tears of laughter at all the funny bits, and in the end we laughed so much it hurt.
It’s here in my Grandmother’s kitchen that I have many a fond memory of my earliest baking efforts, and in their back, less formal living room, many an hour playing card games on folding tray tables tucked up snuggly to well padded armchairs.
The fireplace was in a deco style, with creamy yellow tiles and a thick glass window in the log burner benieth and a poker that I liked pushing embers around with.
The steps by the front door that were painted a shade of blueish grey, that when I was small seemed huge and mountainous, but amazingly they got smaller in later years. The steps out the back by the kitchen lead to my Grandfathers extensive and highly productive and prized vegetable garden, with the garage at the end of the drive and the glasshouse on the other end of the garage.
It’s also a house that is now in the Red Zone that will shortly be no more.
We drove there and I spoke to the neighbour to ask if she thought it would be ok if I took photos, (and explained why), she said Yes, she thinks it’s fine: she knows the disabled man living there at the moment but he’s due to move out very soon, his stuff is being packed up into boxes and stacked in the backroom (That used to be the sunroom that Grandad slept in).
She doesn’t think he would mind, he’s out at work at the moment.
I learn from the neighbour that there are only six people left living in the street, the rest have moved away and the land is slowly getting worse with every decent aftershock.
Liquifaction seeps out over everything every time it rains, subsidence is random in depth but everywhere, she advises to drive down the centre of the roads because a few of the puddles in the neighbourhood are hiding really deep sinkholes.
Since the street is almost empty and some of the few who are left are due to move sooner than later, the City Council won’t be repairing the streets any more… the streets will just slowly continue their process of disintigration as the aftershocks of various sizes continue and nature takes back it’s own.
She tells me that because all the houses in the street are due for demolition soon, that the City Council paid contractors who used to keep the garden neat next door for the disabled neighbour haven’t been there since sometime just after last February’s quake, …so apologies that it’s looking so much more run down that it would in normal circumstances.
I make my way gingerly down the drive.
It’s a short but very emotional journey… the steps out the front are still painted that same shade of blueish gray, the front lawn that had once been my Grandmother’s prize flower garden is now overgrown and derelict, there are deep cracks in the driveway and there is black silty liquefaction over and between the plants all down the side of the drive.
Looking closely there are cracks and chips all over the brickwork of the house, the back steps are now covered up with a ramp for the tenant currently living here, but I remember being daring and jumping off the very top step.
The glass house is gone from behind the garage, there is a small one planted on the other side of the garden where Grandad’s compost heap used to be, but the garage is full of cracks and the garden at the back is as overgrown as the one at the front. Soon, the bulldozers will come, and not just this house, but the whole street and neighbourhood will be razed.
Next time I am in New Zealand this area might be so without landmarks and so overgrown that I may have difficulty finding this spot again.
I wipe away a few tears, say my goodbyes and head slowly back down this familiar driveway of former hopscotch and running races one last time.
I won’t be here to see the bulldozer snuff out the physical life of the place, but that doesn’t matter, it lives on in many happy memories and that’s the way whole neighbourhoods will be for many Christchurch residents now anyway.
We shed a tear for the past but we must always be hopefull that a bright eyed future beckens.
Room on right: I remember it as the sun-room that was also Granddad’s bedroom, to the left of it is the kitchen, and on the other side of the back steps, the laundry.
Cracks continue up the drive and literally cut the garage in half… both through the floor and the brickwork.(I’m pretty sure my father , and ex-carpenter, built this workbench for Granddad, it’s a replica design of one he built in his own garage and still stands today).
Granddad’s glasshouse used to be here, behind the garage.
The room on the left was the guest bedroom, the double bed my sister and I shared had the headboard under the window that faced the drive. The room on the right was Gran’s “best” living room, the one with the china cabinet in it, and where the revelations came to light when the family met together after a day out celebrating my Grandparents 50th… that night will be remembered fondly for the rest of my days.
Granddad’s sunroom on the corner and the less formal, cosy little living room with the window onto the driveway next to it. I’ll miss the yellow Deco fireplace and stacking things up in the airing cupboard to the left to it…
Already, even in the cracks of the driveway, nature fights to return…
The guest bedroom, the headboard was under this window, my sister and I got to listen to the children’s stories on the radio on Sunday mornings whilst having toast on a tray in bed..
Back steps, (obscured by the ramp) with Grandma’s kitchen: by her own admission, she wasn’t a great cook, but her sponge cakes were mind bogglingly tall and light, her slices (bars) and biscuits (cookies) could have revelled any bakery any day of the week and the metal cake tins were always full.
Liquefaction just piles up…