Hi, my name is Julian Thomson and I'm in Wellington which is New Zealand's capital city.
Wellington is renowned for it's wild windy weather.
But also there are several active geological fault lines in the area which cause earthquakes.
One of these fault lines goes right through the city itself, which is a major hazard.
I'm going to be asking some geoscientists from GNS Science to tell me what they know.
We're going to go around the area into several places
to take a close-up look at the fault line itself.
The reason why we have earthquakes and faults in Wellington is because we are riding a plate boundary.
The two plates are effectively in collision
and that collision is giving rise to the land as we know it.
New Zealand is literally being pushed up.
The Wellington Fault runs right through this part of the world
and it is just one of a large number of faults
that form a zone running right through the eastern side of the North Island.
Here we are on the top of Mount Victoria, central Wellington,
and we're going to look at the Wellington Fault, starting off at the very southern end.
It runs out into Cook Strait behind this large hill with the microwave station on top,
through the built-up area of Wellington, out into the harbour
and it runs right along the edge, and then up the Hutt Valley.
This is a great spot, this is a scenic spot on the Wellington coast of Cook Strait
This is Red Rocks Point. Just to the southwest we've got Sinclair Head
And further to the southwest you can see the South Island with the Kaikoura ranges.
This is a fabulous place to see the basement greywacke rocks
that the Wellington fault cuts through.
The most striking thing here is how it's all vertical,
and what we're looking at are the old layers
that accumulated horizontally on the sea floor,
and they're now in the vertical.
The rocks have literally been squashed together, concertinaed,
resulting in a huge amount of shortening of the Earth's Crust, effectively.
What we've got here is the main transportation hub for Wellington.
we've got the main trunk railway here which services all of the North Island,
as well as the domestic trains for Wellington.
We've got the state highway one,
and then on the other side of that we've got the ferry terminal as well as the port.
So this is the real main hub of transportation for Wellington.
Not only have we got all this hub here, but coming in a line underneath that building,
passing under the railway, under the road bridge
and through that silo out into the harbour is the Wellington Fault.
Here we are on the main Hutt Road coming through to Lower Hutt,
and we're standing on the intersection of Te Mome Road and Hutt Road.
If you look over here, we're seeing the roofs of the houses
at almost the same level as the street.
This means that this land where we're standing has lifted up
relative to the other side a few meters over here.
All these houses are built on one side of the fault line,
and we're standing on the other.
The Wellington fault actually goes straight through here along the line of these trees,
straight down the middle of this median strip.
You'll see that the houses have been set back, and this was done on purpose
because they knew where the fault was, they mapped it, and put the houses on either side.
We're at California Park here, the Wellington fault is really well expressed in this park.
Let's go for a walk and I'll show you what it has to say.
This is ground surface that were on, used to be an old riverbed of the Hutt River,
the Wellington fault's moved up and sideways, and that's this bump that we see,
and that's how they knew where the fault was,
to keep the houses away California Drive.
We're on the South bank of the Hutt River here,
and the Hutt River at this place, is crossing the fault almost at right angles.
As it's eroded away the North bank, it's exposed the Wellington fault.
It is right at the downstream end of that bluff
where the brown gravels meet the blue gravels.
This is the best exposure of the fault.
Last earthquake happened about 300-400 years ago. When will it happen next?
Well, we do whole lot of earthquake research geared at two points.
One, perhaps to figure out when it will happen next,
but more importantly, to get the infrastructure and the community resilient for when it does happen.
It takes generations for a community to build resilience
so even if you could predict an earthquake, it doesn't protect the infrastructure
It's a probability thing, and the probability of it moving in the next 50 years is about 10 percent.
Well that's been quite a journey, it's been perhaps a bit more than I expected.
I've lived in Wellington for a number of years
and I've not seen all of those views and learnt all of those things
that I just found out on with wonderful tour.
It's also made me quite thoughtful about the the reality
of having a an active fault line going through our hometown.
I hope you've enjoyed the experience, and I hope you've learned a lot.
If you want to find out more or do some trips of your own,
go to our website, there's lots of information there all about the Wellington fault.