Why New Zealand doesn’t need to worry about a zombie apocalypse

New Zealand has been hit by three significant earthquakes in the last two days. Luckily not strong enough to do damage, and remote enough that even a larger shake would have been more nuisance than apocalypse. But they are a sharp reminder that we live on some very ‘shaky isles’. The next one might well bring tragedy.

The Christ Church Cathedral - icon of a city for nearly 150 years and the raison d;'etre for its founding in 1850. Now a ruin, due to be demolished.

The Christ Church Cathedral – icon of a city for nearly 150 years and the raison d’etre for its founding in 1850. Now a ruin.

It’s to get a better handle on that looming apocalypse that GNS Science have been exploring the Alpine Fault this past few months – drilling far down to set up an early warning system that will give us some prior hint when is about to rupture. Not if, but when – this fault moves every three centuries or so, and it last ruptured in 1717. Go figure.

Well, actually you don’t have to. A study published in 2012 indicated there was a 30 percent chance of a devastating quake occurring on that fault some time in the next 50 years – before 2062. Because probabilities are calculated as bell-shaped curves, this did not mean a quake would occur precisely in 2062; it meant the quake might occur any time from 2012 (low probability) through the mid-twenty-first century (high probability), to the early 2100s (a low chance of it happening that late, but a very high probability of it happening, if it hadn’t happened by then).

This fault is thought capable of generating quakes with magnitude of up to 8.3. Huge. A Civil Defence exercise held in 2013, built around that potential, can best be described as scary. While researching my book on earthquakes, I contacted the author of the exercise – who filled me in on the details. Uh…ouch.

For obvious reasons the science of earthquake engineering is well developed in New Zealand. Some of the world’s leading systems have been invented here, notably the lead-rubber base isolator. This is designed to keep a building ‘floating’ above its foundations. When an earthquake hits, the ground moves – but, thanks largely to its moment of inertia and the reduced energy being transmitted to it, the building doesn’t. Not so much anyway. The first system was installed in the early 1980s in what was then the Ministry of Works building, and major structures to receive it since have included Te Papa Tongarewa, the national museum; and Parliament buildings.

It’s a clever idea. And tricks like this – along with a raft of others – all have to be applied quite seriously in earthquake zones. One of the outcomes, certainly as far as civil defence planning is concerned, is that the likelihood of casualties during the quake is reduced. Buildings constructed with proper attention to earthquake-proofing won’t collapse, and if they’re done right, they also won’t shed parts that crush people beneath. That’s what caused most of the casualties in the 1931 Napier earthquake, for instance, which provoked New Zealand’s first serious earthquake-proofing regulations.

Study, inevitably, is ongoing. But what I can say is that New Zealand doesn’t need to worry about a ‘zombie’ apocalypse. The ‘earthquake’ apocalypse we’re actually facing is serious enough. For more…well, you knew I’d say this – it’s all in my book.

Copyright © Matthew Wright 2014

Click to buy from Fishpond.

Buy from Fishpond.

Click to buy from Fishpond

Buy from Fishpond

Click to buy e-book from Amazon

Buy e-book from Amazon

Forecasting New Zealand’s seismic apocalypse

This weekend’s tragedy on Japan’s Mount Ontake reminds us that life around the Pacific ‘rim of fire’ is often risky.

That string of tectonic plate collisions stretches around the whole circumference of the Pacific and has shaped life in many ways. It was cause of the 2011 tsunami that devastated eastern Japan. It gave the US Yellowstone. It provokes earthquakes. It has also shaped my home country, New Zealand – and has been doing so for at least the past ten million years. The obvious question is ‘what next’ – something that has exercised seismologists and vulcanologists for generations. One way of finding out is to look back into the past, figuring out where fault lines are and how often they move.

Karaka Bay - on the eastern side of the city where Port Nicholson opens out to the sea through a narrow channel.

Karaka Bay – on the eastern side of the Miramar ‘was-an-island-before 1460′ Peninsula

That’s certainly been a focus of ongoing work in New Zealand, which straddles the collision between the Australian and Pacific plates and is prone to massive earthquakes. And of all the historical quakes, it seems few were as spectacular as the series that ripped through the country around 1460, as an indigenous Maori culture began to emerge from its Polynesian settler origins. All of them were around magnitude 8 or higher. They began, it seems, in the south as the Alpine Fault moved. Then there was a quake off what is now Wellington. And another in the Wairarapa. And another at Ahuriri, creating the Te Whanganui-a-Orotu lagoon. Wham! Tsunami followed, 10 metres or more high.

Maori refer to the 1460 Wellington quake as Haowhenua – the ‘land swallower’. Superficially that’s a paradox; the quake created land, raising the channel between Miramar, then an island. But the quake also triggered tsunami, washing far around the coasts and inundating settlements and gardens on the south coast of the Wairarapa. For Maori, the key issue was the loss of food-stuffs by a disaster that had, literally, swallowed their land.

It's all in an ordinary industrial-style street.

This movie studio in central Miramar was underwater before 1460.

A succession of quakes of this magnitude remains unprecedented. Seismology, to date, has usually treated quakes as independent events. And yet it’s clear that earthquakes occur in clusters, and seismologists have been asking questions of late that point to connections. One of those is interactions between fault lines. A quake on one fault might deliver enough energy to a nearby fault to trigger it, providing that fault was already under stress. There is also the effect of ‘slow quakes’. This only emerged in the early twenty-first century when GPS measurements revealed that, at certain points where the Pacific plate dives under the Australian – usually east or west of the New Zealand land mass itself – there are areas where the two slip slowly, but not smoothly. Huge earthquakes follow, but the energy released is spread out over months and not detectable by conventional instruments.

What these quakes seem to do is stress shallower fault lines, east in the plate interface. Current analysis indicates that a slow-slip quake under Kapiti island in early 2013 was likely cause of the succession of conventional quakes that struck in a semi-circular arc around Kapiti from mid-2013 – the Cook Strait and Grassmere quakes of July and August; the Eketahuna quake of January 2014; and the Waipukurau quake of April 2014.

All were severe quakes, but not in the league of the 1460 series. As yet the jury’s still out on the linkages. If the hypothesis is right though, the issue is obvious. Slow quakes might provoke successions of conventional shallow quakes in New Zealand. And if the 1460 sequence was one of those, it’s clear these quakes can be large indeed.

That begs a question: what would happen were New Zealand to suffer a similar quick-fire succession of huge quakes? That’s something I’ve tackled in my book Living on Shaky Ground (Penguin Random House). I won’t repeat the details here – suffice to say, it’s spectacular and I can’t help thinking that Mars looks appealing about this time of year.

Copyright © Matthew Wright 2014

Click to buy from Fishpond.

Buy from Fishpond.

Click to buy from Fishpond

Buy from Fishpond

Click to buy e-book from Amazon

Buy e-book from Amazon

Living On Shaky Ground

I’ve got three books being published between now and February.

Here’s a preview of Living On Shaky Ground: the science and story behind New Zealand’s earthquakes. It’s being published by Penguin Random House on 26 September. My advance copy arrived a few days back. And after thirty years and over 50 books, I have to say that the thrill of receiving the advance, unseen by anybody else except the publishers and the printers – never goes away.

My advance 'author copy' of Living On Shaking Ground - with its delivery packaging...

My advance ‘author copy’ of Living On Shaky Ground – with its delivery packaging…

And here it is in its 'natural habitat', a bookshelf, lined up with both editions of my last book on earthquakes.

And here it is in its ‘natural habitat’, a bookshelf, lined up with both editions of my last book on earthquakes.

The book includes over 50 photos I took myself, a lot of science text on earthquakes, and the story behind some of New Zealand’s bigger ones. The main – er – thrust of it it isn’t about the past, of course, but the future – what’s going to happen next?

More soon. And if you want to buy…it’s available for pre-order now, via New Zealand’s online bookstore Fishpond.

Copyright © Matthew Wright 2014

Click to buy print edition from Fishpond.

Click to buy print edition from Fishpond.

Ever get that feeling of quake deja vu?

Monday was the provincial anniversary holiday in Wellington, New Zealand. Kind of cool – the provinces were abolished in 1876, but we still get the holiday.

Around 4 pm the house began shaking – slowly at first and then quite violently. We get a lot of small quakes. This wasn’t one of them. In fact, it seemed up there with last year’s big quakes.

The science behind it is fascinating. New Zealand has an automated seismic network that publishes estimated figures to the internet in near-real time. The first official figures – calculated by the duty seismologist – were available within fifteen minutes, with a final refined value just over an hour afterwards. This quake, at magnitude 6.2 and with an epicentre near Eketahuna in the Wairarapa, was classified ‘severe’. It was 33 km deep – felt widely, but not so destructive as the shallow quakes that hit Christchurch in 2010-11 and Wellington in 2013. It occurred in the Pacific plate subduction zone, where the plate is being driven down by the Indo-Australian plate riding up over it. It’s no coincidence that this is right under New Zealand – the islands are a product of that collision.

Gollum in Wellington airport passenger terminal - a marvellous example of the model-maker's art.

I don’t have a photo of the Wellington airport eagles, but this is Gollum – taken last year – near the model that fell into the foodcourt. Click to enlarge.

Where I live the ‘felt intensity’ was at the high end of V on the Modified Mercalli scale. Damage around Wellington included the Weta workshop model of a Hobbit eagle  in the airport terminal, which crashed into the food-court. It was worse across the lower North Island in centres like Palmerston North. Fortunately nobody was killed or hurt.

Quakes have been on the rise in New Zealand lately. Archaeological work reveals that quakes cluster in decades-long patterns. The late twentieth century was one of the calmer periods. And now it looks as if we’re back in the action again. Christchurch, alas, may have simply been the beginning. Are they linked? Possibly. Certainly a quake in one area can increase stresses in a fault nearby that’s already under tension. But there also seems to be a general process of rising and falling activity.

The Christ Church Cathedral - icon of a city for nearly 150 years and the raison d;'etre for its founding in 1850. Now a ruin, due to be demolished.

The Christ Church Cathedral, Christchurch – photo I took in early 2013. Click to enlarge.

Best case is it will settle down. Worst case – well, there is a disturbing precedent from the fifteenth century, where a succession of massive quakes estimated at magnitude 8+ tore along the length of the country over just a few decades. One of them, circa 1460, struck just south of Wellington and filled in one of the two harbour entrances, the Te Awa-a-tia channel. Motukairangi island – modern Miramar – became a peninsula and the water within its hills swampy terrain. Peter Jackson’s studio is built on the uplifted land.

It's all in an ordinary industrial-style street.

Warehouses opposite Peter Jackson’s Park Road headquarters, Miramar – under water until 1460. Click to enlarge.

Maori named the quake Haowhenua (‘the land destroyer’). The evidence is still visible as the flat land of Miramar and the Wellington airport flats – and as beach lines at Turakirae Head. The name seemed a puzzle – a ‘land destroyer’ that produced uplift? Then archaeologists discovered evidence of 10-metre tsunamis at the same time.

The question is not ‘if’ this will happen again – but ‘when’. New Zealand has many fault lines – the largest is the Alpine Fault, which moves about every 300 years and generates quakes of magnitude 8+. We are due for one, statistically, within 50 years. Recent studies point to the existence of other large faults each side of the South Island. They are still being researched. Scary? No.  We have to accept the reality as it unfolds – and be prepared.

Do you live in an earthquake zone? If not, what natural disasters do you face?

Copyright © Matthew Wright 2014

Coming up: More writing tips, science geekery and humor. But hopefully not more quakes. For a while, anyway.

Mindless parking warden droogery in a quake-hit city

I posted last week about the way central Wellington had quietened after the July earthquake.

The dis-assembled crane in Luke's Lane - filling the lane - with the teetering lift shaft and 30-ton slab atop visible behind, propped up by another crane. Funny, why haven't the parking wardens ticketed the crane?

The dis-assembled crane in Luke’s Lane – filling the lane – with the teetering lift shaft and 30-ton slab atop visible behind, near the boom of another crane. Click to enlarge.

I think it was largely because the two largest central city parking buildings had been shut down – and parking in the streets is a lottery in the face of the Wellington City Council’s parking enforcers –  whose mind set, to me, was summed up when they deployed a spy car whose occupants intimidated motorists and issued tickets to drivers for ‘parking offences’ while they were actually on the road, waiting to turn left.

An earthquake emergency, it seems, makes no difference. Here are photos I took on Monday of Luke’s Lane, where an external lift shaft adjacent to one of the parking buildings was left unsafe in the 6.5 magnitude July quake. The 6.6 magnitude shake of Friday 16 August finished the job; it was at high risk of collapse, urgent demolition indicated. One of the biggest mobile cranes in the country was brought up from the South Island – with the help of 10 flatbed trailers and prime-movers – to remove a 30-ton slab of concrete at the top of the collapsing shaft, as the first stage of the demolition process.

Meanwhile a security company was asked to keep the public out of the lane over the weekend. While they were doing it, the Council’s parking enforcers ticketed their vehicles.

Man, that crane is one big sucker.

Man, the boom alone fills the lane – now waiting for the rest of the crane to arrive.

The Council admitted that the incident was over the top, but you have to wonder about the corporate culture that cultivated this mind set in the first place.

What would happen if the guards weren’t there and the slab fell? You can imagine it crushing some passing pedestrian – and the corpse being found next day with infringement notice taped to the forehead for loitering in a legal roadway.

Reducto ad absurdium? Maybe.

Copyright © Matthew Wright 2013

Wellington struck by more severe quakes – 16 August

As I write at 5.30 pm, my desk is rocking to three quakes in quick succession, the largest at magnitude 6.3. These are just the latest in a string that have hammered my city, Wellington in a few hectic hours this afternoon, just a month after another swarm that, we were all hoping, might be over.

Soon after the biggest – a 6.6 magnitude shock – swept over the city at 2.31 pm, the streets were filled with cars and people, getting out of town. Here’s a photo I took with my phone looking across to Parliament buildings, at the base of Molesworth street.

Pedestrians and cars at the bottom of Molesworth Street, Wellington, after the magnitude 6.6 shock of 16 August. Aftershocks up to 5+ magnitude were still rolling in when I took this.

Pedestrians and cars in unusual number at the bottom of Molesworth Street, Wellington, after the magnitude 6.6 shock of 16 August. Aftershocks up to 5+ magnitude were still rolling in when I took this.

Really, of course, we have to think of these quakes as a single large event – one with punctuated movements. What’s more, there have been other quakes around the country, likely triggered by the latest re-eruption. The ones rocking Wellington are all centred on a fault line under Cook Strait, near the South Island town of Seddon – which has taken a severe hammering.

I’d like to extend a very warm and grateful thanks to all those who got in touch with me, within a few minutes of the news spreading – and from as far away as the US – to ask how things were going. I very much appreciate your kind thoughts – thank you.

There are no injuries reported. More soon.

Copyright © Matthew Wright 2013

Thoughts on a quietening city after earthquakes

I like Wellington, as a city. It is a compact place, a Saturday evening stroll through the café district an exciting wash of colour, people, smells and sound. Yet since a wave of earthquakes began sweeping over my city, nearly three weeks ago, the city centre is quiet.

Courtenay Place, Wellington 10 August 2013. I took this hand-held with my SLR, exposure time 1/6 second, ISO rating of 800. Hand held on a sixth-second exposure time. Just saying.

Courtenay Place, Wellington 10 August 2013. I took this hand-held with my SLR, exposure time 1/6 second, ISO rating of 800. Hand held on a sixth-second exposure time. Just saying.

Normally these streets would be way more crowded on a Saturday evening. Even the opening of ‘New Zealand’s Got Talent’ across the road didn’t do more than make that side of the street look normal for a Saturday night.

I took this with my phone - quality's not quite up to SLR standard.

I took this with my phone – quality’s not quite up to SLR standard.

I don’t think it’s worry about another quake. Our seismologists are good; the risk’s low.  People are philosophical about the risks and nobody I’ve spoken to is worried. No, that’s not the problem. I suspect a large part of it is the fact that half the parking buildings are closed. Other parking building owners have elevated prices to ‘highway robbery’ level in response.

Parking on the street is suicidal in the face of a vicious guilt-on-existence Council parking enforcement system – and you don’t have to be in a carpark to be ticketed. For a while they had an enforcement spy car roaming the street photographing drivers and ticketing people that included one motorist waiting to turn. I am not joking, it got to court. The Council lost, and the incident did nothing for their repute.

Another phone picture. I wonder about this building. The upper floors are a timber-frame add-on, which to me says that in a really big quake they'll perform differently from the reinforced concrete structure below.

Another phone picture. I wonder about this building. The upper floors are a timber-frame add-on, which to me says that in a really big quake they’ll perform differently from the reinforced concrete structure below.

Elsewhere, a few buildings are empty in the face of structural cracking and safety concerns. But the main new look is the profusion of bucket cranes with glaziers atop them, replacing broken windows.  I thought I’d share a few images I took.  I used my phone, so they’re not quite up to SLR standard. But hey…

Apart from the parking difficulty, people are philosophical, cheerful – quakes are part of life, sure. But not something to get wound up about. It wasn’t the ‘big one’. And it’s been a useful wake-up call. Next time, we’ll be better prepared.

Copyright © Matthew Wright 2013