Sanitation concerns in post-quake Christchurch
Wendy Zukerman, Australasia reporter
In the New Zealand city of Christchurch authorities are scrambling to restore water supplies and sewage systems which were severely damaged by last week’s 6.3-magnitude earthquake.
(Image: Jamie Ball/Rex Features)
Isolated cases of measles and gastroenteritis have been reported. According to Humphrey the gastro cases were likely to have been water-borne and the result of people brushing their teeth with contaminated water – rather than spread through human contact.
But, a Canterbury District Health Board spokeswoman told the New Zealand Herald: “There is an underlying potential for there to be a measles outbreak. There’s a chance of an outbreak of gastro diseases.”
Many residents are living in camps, where the poor sanitation and cramped living conditions are perfect for disease outbreaks.
On Friday, Cowles Stadium welfare centre – which provided accommodation for Christchurch earthquake evacuees – was forced to close because its water and sewage services were not considered reliable.
Radio New Zealand reported that the Christchurch City Council was “worried about disease” at the stadium, and said it could not “afford an outbreak of diarrhoea.”
All citizens are being encouraged to boil their water before consuming it.
At 12.51 pm local time today – precisely one week from when the earthquake struck, burying as many as 200 people - the city stood silent for 2 minutes.
Mental health is seen as a growing concern in the city, too. A doctor from a nearby hospital that has been helping patients told the New Zealand Herald, “We had walking wounded coming in initially on Tuesday – people with cuts, minor injuries and things like that. We are starting to get more people with shock coming in and I expect that to increase.”
The tectonic forces that are shredding New Zealand
The week of 22 February the New Zealand city of Christchurch felt the force of a 6.3-magnitude earthquake. The quake came just five months after an even larger one struck 40 kilometres west of Christchurch, near the town of Darfield. In fact New Zealand experiences around 14,000 tremors each year, although most are too small to be felt. They are a sign of the tectonic processes that are gradually shredding the country.
Why is New Zealand so prone to earthquakes?
Regions that lie close to a boundary between tectonic plates tend to feel more quakes than areas in the middle of a plate. New Zealand may have a total land area of just 27,000 square kilometres, but that area happens to coincide with the margin between the Pacific and Australian plates, leaving parts of the island very seismically active.
Which areas are most vulnerable?
Large areas of both North and South Islands have felt earthquakes with a magnitude greater than 5 within the past 200 years. This is because of New Zealand’s unique tectonic regime: despite its small size, the country feels the impact of three distinct regions of tectonic activity.
The relatively low-density continental crust of the North Island, which sits on the Australian plate, is forcing the dense oceanic crust on the Pacific plate beneath it in a process called subduction. This creates a so-called destructive plate margin that is nibbling away at the Pacific plate. Earthquakes are common where a subducting plate grinds against the underside of an overriding plate.
Something similar is occurring to the south-west of South Island. But here the sliver of continental crust lies on the Pacific plate, and it is the Australian plate that is being destroyed through subduction.
In between, the continental crust on the Pacific and Australian plates slide past one another on South Island, creating a conservative plate margin where crust is neither created nor destroyed. This area is still prone to earthquakes, most notably along the Alpine fault. Further away from these fault zones the ground is generally more quiescent. Christchurch is over 100 kilometres from the Alpine fault.
So what caused the Christchurch quake?
It was caused by a new fault – or, to be more precise, a previously unrecognised fault.
“The fault is likely to have existed previously – and possibly produced earthquakes before – but they have not ruptured recently, in a geological sense,” says John Townend at the Victoria University of Wellington, New Zealand. The unrecognised fault appears to be an offshoot from the Alpine fault. Unfortunately for the residents of Christchurch, that offshoot passes very near South Island’s largest city.
Are more quakes on the fault likely?
Earthquake prediction is an inexact science, despite tantalising evidence thatearly warning systems may be possible in some cases. But some seismologists are cautiously optimistic.
“An earthquake of this magnitude does a good job of releasing stress,” says Gary Gibson, a seismologist at the University of Melbourne, Australia. Townend agrees: “My interpretation of what we are seeing near Christchurch is temporary, albeit harrowing, activity in what is generally a relatively low-seismicity part of the broad plate boundary.”
What’s the long-term prognosis for New Zealand?
Even if Christchurch dodges major seismic activity in the near future, tectonic forces will continue to act on New Zealand. Hamish Campbell at the research consultancy GNS Science in Lower Hutt, New Zealand, says it’s “very unlikely” that the newly recognised fault will have any serious effect on the country’s geography, but activity on the Alpine fault may well do so.
The rocks on either side of the Alpine fault are grinding past each other quickly – at around 30 millimetres per year. The southern part of South Island has moved at least 480 kilometres relative to the northern part within the past 25 million years. That rate of movement is “colossal”, says Campbell – and not far off the displacement seen on the world-famous San Andreas fault in California, which is itself a conservative plate margin.
Fast forward several million years and New Zealand will continue to twist and turn. The activity that is already shredding the country will ultimately see South Island “split in two along the Alpine boundary”, says Campbell. The town of Kaikoura would be at the northern tip of one island, with Greymouth at the southern tip of the other, he predicts.
The Alpine fault that runs along the mountainous spine of South Island marks the boundary between the Australian and Pacific plates. It now appears likely that the Christchurch quake resulted from a previously unknown fault extending directly eastward from the Alpine fault.
It first came to light last September when a stronger but less calamitous quake shook Darfield, 40 kilometres west of Christchurch. Seismologists believe the latest quake resulted from …
Today’s fatal earthquake near Christchurch in New Zealand confirms that a country already riddled with major fault lines has gained another one, say seismologists.
“Christchurch has never been identified as a major earthquake zone, because no one knew this fault ran beneath,” says Roger Musson, a seismologist at the British Geological Survey in Edinburgh.
New Zealand experiences thousands of earthquakes each year, because it lies on the boundary between the Pacific and the Australian tectonic plates. To the north-east, the Pacific plate is subducting beneath New Zealand’s North Island, and to the south-west, the Australian plate is subducting beneath the South Island. Between these two subduction zones lies theAlpine fault, running along the mountainous spine of the South Island.
It now appears likely that the Christchurch quake resulted from activity on a fault extending directly eastward from the Alpine fault that remained unknown until last year, says Musson.
The new fault first came to light last September when a stronger but less calamitous quakeshook Darfield, 40 kilometres west of Christchurch. Musson says the latest quake probably resulted from an eastward continuation of activity on the same fault. “It has probably not moved for tens of thousands of years, so lots of strain built up,” says Musson.
Christchurch was understandably unprepared for activity on a fault that is only now making its presence known. But two factors made today’s damage worse. The quake was just 5 kilometres down, limiting the amount of energy it dissipated before reaching Christchurch from its epicentre just 10 kilometres away. Also, the rock on either side of the fault accelerated almost three times as fast as in a typical quake, says Musson, so the shaking was extra violent – and significantly greater than the levels Christchurch’s structures have been designed to withstand
A series of floods have been affecting northeastern Australia, primarily in the state of Queensland and its capital city, Brisbane, since October 2010. The floods have forced the evacuation of thousands of people from towns and cities. At least 22 towns and over 200,000 people have been affected. Damage initially was estimated at around AU$1bn (£650m). This estimate was later revised up to AU$10-11bn.
Vast areas of Southern and Central Queensland, an area the size of Germany and France combined, were affected by the flood. About 300 roads were closed, including nine major highways. Coal railway lines were closed and numerous mine sites flooded. The floods have boosted fruit and vegetable prices.
The floods were a result of heavy precipitation caused by Tropical Cyclone Tasha that combined with a trough during the peak of a La Niña event. The 2010 La Niña weather pattern, which brings wetter conditions to eastern Australia, is the strongest since 1973. Isolated flooding started across parts of the state in early December. On 24 December a monsoonal trough crossed the coast from the Coral Sea, bringing torrential rain that fell in a broad swath from the Gulf of Carpentaria to the Gold Coast. By 28 December the worst of the rain had passed. The conditions also led to a large influx of snakes, as well as some crocodiles.
While flooding has been widespread across Queensland, major flooding has mainly occurred in the three river basins.
- Fitzroy River basin, including the Dawson and Nogoa Rivers
- Burnett River basin
- Condamine River/Balonne River basin, part of the Murray-Darling basin.
A later flood event affected the Mary River basin
Fitzroy River basin
The flooding initially forced the evacuation of 1,000 people from Theodore and other towns, described as unprecedented by the acting chief officer of the Emergency Management Queensland. The military transported residents by helicopter to an evacuation centre at Moura.
Emerald was cut-off by road on 29 December as the Nogoa River rose. By the next day, the river surpassed the 2008 flood peak level of 15.36 m (50.4 ft). At the peak of the flooding, 80% of the town was flooded, the worst the town ever experienced. 1,200 Emerald residents registered as evacuees.
Rockhampton had nearly a week to prepare for an expected flood peak from the Fitzroy River, which courses through the centre of the city. The airport was closed on 1 January. A metal flood barrier was erected around the terminal to prevent flood-borne debris from causing damage to the structure. An evacuation centre was set up at the Central Queensland University. The Bruce Highway leading south out of Rockhampton was closed to traffic. The river peaked at 9.2 m just short the of the predicted 9.4 m maximum.
The Port of Gladstone reduced its export capacity because the coal stockpiles at the port were saturated and further coal deliveries could not be made by rail. The Goonyella railway line which services a number of coal mines in the Bowen Basin was closed for one week and shipments of grain were also delayed.
Burnett River basin
The swollen Burnett River at Gayndah, 350 kilometres (220 mi) north west of Brisbane.
The central Burnett towns of Gayndah and Mundubbera saw major flooding on 28–29 December. The Burnett River peaked at 18.25m at Mundubbera—the highest river height since 1942—inundating more than 20 houses. Downstream at Gayndah, the river peaked at 16.1m with floodwaters reaching two houses. Both towns were isolated for several days and there was major disruption to the potable water supply and local agricultural production.
Condamine/Balonne River basin
Flooding in Dalby was the worst since 1981. The town’s water purification system was flooded, resulting in water restrictions that have hampered clean-up efforts. 112,500 litres (24,700 imp gal; 29,700 US gal) of water were transported to the town of 14,000 residents. Warwick was isolated when all roads into the town were cut-off.
Floodwaters are passing downstream along the Balonne River and threaten the towns of Surat and St George. The river is expected to peak at 12.5m at Surat and 14m at St George. The New South Wales towns of Angledool, Goodooga and Weilmoringle are expected to be isolated when floodwaters from the Balonne reach the Culgoa and Bokhara Rivers.
Mary River basin
Heavy rain in the Mary River catchment on 8-9 January 2011 lead to flooding at Maryborough and Gympie. The Mary River at Maryborough was expected to initially peak at 8.5m at midday 9 January with some houses and businesses inundated. A second peak is expected to arrive from rain falling upstream later that day. At Gympie, the Mary River is expected to peak at 16m, possibly increasing to 17m—over the major flood level—if rain continues to fall.
Toowoomba flash flood
In the Darling Downs, the city of Toowoomba was hit by flash flooding after more then 160 millimetres (6.3 in) of rain fell in 36 hours to 10 January 2011; this event caused four deaths in a matter of hours.
Nearby, Gatton saw voluntary evacuations as the Lockyer Creek rose to a record height of 18.92m, exceeding the previous record set in the 1893 Queensland floods. The surge passed through the Lockyer Valley town of Withcott, where the force of the water pushed cars into shops and forcing the evacuation of hundreds of people. The scene was described by an onlooker as “like Cyclone Tracy has gone through it … If you dropped an atom bomb on it, you couldn’t tell the difference.” Grantham was also hit hard by the flooding rains. Houses were left crumpled by what Premier of Queensland Anna Bligh described as an “inland tsunami“. Nine people were confirmed dead, with the toll expected to double that figure, and 66 were missing.
In South East Queensland, the Wivenhoe Dam filled to a level equivalent to 122% of its supply capacity, leading operators to open all five flood gates on 29 December. Brisbane experienced its wettest December since 1859.
On 11 January 2011 at around 2:30 pm EST, the Brisbane River broke its banks leading to evacuations in the Brisbane CBD and the suburbs of Fortitude Valley and West End. An evacuation centre was established for flood-affected residents at the RNA Showgrounds in Bowen Hills.
Avatar is about our battle for earthly resources reflected in how we view the natural world, its cultures and ourselves. As a film experience, it uses latest special effects to show a adventure ‘about’, ‘in’ and ‘for’ the environment; however it does so much more than this, in the way it very intelligently develops a series of themes on a number of levels.
A US Marine, Jake Sully, is tasked with finding out about what seems at first an alien environment, getting to know its inhabitants, and thereby enable his military bosses to discover how to conquer it for the precious mineral and so rescue Planet Earth from an energy crisis.
With the help of his new companion Neytiri, a girl of the Na’vi people, he struggles, but eventually succeeds, in learning about the natural world around, how he can not only tolerate it, but work and play within it, and gain to respect it. Animals and plants that at first are appear hostile, are shown to be defensive, just as he was first. Through gaining and consolidating his skills and knowledge, Jake learns how to source the basics – food, water and warm – by a growing understanding of the rhythms of nature. There are strong resonances here with regards to children’s desire to ‘be outdoors’ and the bush experiences encouraged as part of outdoor education, so often lacking in what has become known as ‘nature deficit disorder’ in many highly urbanized young people.
This ‘fish out of water’ feeling is highlighted when he comes across animals and plants that glow at night, when disbelief and uncertainty are replaced by wonder and ‘being’ in the moment. Disbelief makes way for ‘taking charge’ when Jake must choose his own animal to ride. Here the animal might kill if he shows fear, but accepts his rider when they none. An animal in the natural state can ‘smell’ fear and reacts negatively to it; a false move – running – might mean death for the person, as a mistake!
These experiences give way to a fresh awareness of the fragility and sacredness of all life, so values now come to the fore. When killing an animal, Jake is seen to make peace with its spirit – acknowledging a new concept that he had likely not considered before he came to Pandora.
With all this new-found awareness, of the natural world, all of its many aspects and the tribe’s connectedness to it – Jake realizes that the very people who brought him to Pandora, and their technology, seek only to take what they want and move on with it.
This same technology, which provided the ‘way in’ to this other world by way of the Avatar Programme, now threatens its very existence. The invasion of men and machines – for the minerals and resulting wealth, and against the indigenous peoples and their sacred lands – is no less a metaphor than a historical truth. Whether it is the American Indians versus the US Government, or the prospectors going into the Amazon Basin – or indeed, some would argue, the Iraq War – this game of White invader going after local people for their natural resources, is a pattern all too familiar. However, familiarity does not breed contempt as some have argued, since history keeps on repeating, yet we are not listening!
Despite reaping deep and massive destruction to the landscape and ecology – if not unlike a nuclear, than certainly similar to the Amazon burning! – an invasion is ostensibly halted with Nature’s help.
Avatar holds a candle to our entire approach to the natural world, drawing in historical presumptions that block our potential understanding of the future us and our relationship with the planet, and through this, everyone who calls it home. Only those with the true and growing understanding of Nature and our range of responses, can we see our way forward to a life lived in harmony on our planet.
If the world of Pandora is so easily likened to our burning habitats, invading countries and displacing indigenous peoples now, Avatar – for its make-believe take – is uncomfortably more real than we would like!
In The Times online
‘As rescue efforts work around the clock to pull survivors from the rubble, geologists around the world have put their day-to-day calculations and lab meetings on hold and are already sifting through seismic data collected at the time of last night’s earthquake in Haiti.
This isn’t a case of clinical academic curiosity. Predicting what is likely to happen in the next hours and days is vital for a well run rescue operation. Following an earthquake of this magnitude, aftershocks are to be expected and people in the region will need to know where, when and what size tremors they face.
The magnitude of the quake (7.0 on the Richter scale), which occurred at 21.53 GMT, was not extraordinary. But it’s proximity to Port-au-Prince – 15km (10 miles) – and that it occurred at such a shallow depth - 8km (5 miles) - were a unusually destructive combination. “Closeness to the surface is a major factor contributing to the severity of ground shaking caused by an earthquake of any given magnitude. Furthermore, shaking tends to be greatest directly above the source,” said Dr David Rothery, a planetary scientist at the Open University.
MY VIEW: Scientists with instrumentation may appear ‘absent-minded professor-types’ but their work and awareness is not only vital to understanding of the Earth, but how and when it is safe to respond the very real and tragic consequences such as Haiti’s earthquake.
Excerpts from The Times online: http://timesonline.typepad.com/science/2010/01/haiti-earthquake-scientists-and-rescue-workers-1.html
‘The reasons for depth being an issue are twofold. First, the energy from the quake spreads out in a spherical wave into the surrounding area, meaning the closer you are to the source, the less dissipated the force. Second, deeper beneath the earths surface the temperature and pressure is so great that the rocks bend and squash rather than rupturing. An analogy can be made with toffee – it bends when its warm but shatters when cold.
The earthquake was caused by a similar type of movement that occurs on the San Andreas fault: A sideways slip occurred on a fault that marks part of the northern edge of the Caribbean Plate and the North American Plate. Geologist Chris Rowan illustrates the tectonics in this posting on the Highly Allochthonous blog. http://scienceblogs.com/highlyallochthonous/2010/01/tectonics_of_the_haiti_earthqu.php
A magnitude 7.0 earthquake struck Haiti this evening, causing extensive damage to the capital, Port-au-Prince, and probably causing many casualties. The map below shows where the main shock occurred (red), as well as the epicentres of the numerous aftershocks (orange) that occurred in the following 5 or 6 hours (and continue even as I write).