http://environment.newscientist.com/channel/earth/mg19526141.600-huge- sea-level-rises-are-coming–unless-we-act-now.html

At one point the Great Alpine Fault is less than 150km from Christchurch and combined with the geology of the Canterbury plains parts of Christchurch and North Canterbury could experience collapse of masonry buildings. If the quake happened today the waterlogged soil would cause quite a bit of liquifaction in Kaiapoi and slope failrures in the Port Hills suburbs.

It is more equivalent to the Great Wellington quake circa 1850 that lifted much of the CBD above sea level.

I designed something very similar for my parents place on the beach in Sag Harbor… we didn’t build it (I was not yet an engineer and there was never any money), but aside from using regular pontoons rather than foam filled, it was exactly the same.

After everyone stopped laughing they realized I was serious. Eleven year olds often are more serious than you expect.

respectfully
BJ

Preditions for sea level rise will be less precise than predicting faultline earthquakes because scientists can’t simply look at the past to narrow down the range of options for the future. Your guesstimate of sometime between next week and next century is reasonable given the limited knowledge currently available of the various causal mechanisims and there potentially cmplex and non-linear interactions.

To date the best prediction paleoseimologists have been able to cme up with for the Great Alpine Fault is 50% probability within 30 years, 90% probability within 100 years, 95% probability it will register 7.9 +/-0.25 and involve betwee 300km and 500km of the northern most portion of the Great Alpine fault.

What sort of time frame are we talking here? Sometimes I’m not sure whether the sea will rise next week or next century.
jh

Those sea level maps show that a 1 metre rise can affect river levels up to several hundred metres inland. In most pleces this will be like having a permanent spring tide. This is going to dramatically reduce peak river flow capacities so there will be more frequent floods in places like Greymouth, Blenheim, North/east Christchurch and across the Napier/Hastings Motorway. We are going to have to make the hard decision that London has made and actually return much of our flood plains to the role nature intended them to have instead of trying to build ever higher stopbanks.

A one metre increase in sea levels is effectively a one metre reduction in the height of groynes, sea walls and other coastal defences. This is going to be major problem on some of our most important tourist highways particularly in south Westland and north of Kaikoura where roads (and the railway) can’t be moved away from the ocean.

We only need to look to our nearest neighbour to see how they deal with tens and hundreds of refugees. Is that how we are going to treat the millions of people currently living in low lying areas?