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The earthquake which devastated the city of Padang in Sumatra, Indonesia, this week, killing more than 1100 people, may have been only a hint of worse to come. Since 2004, geologists have been predicting a far nastier earthquake in the region – a shallow tremor that will rip the sea floor apart, trigger a devastating tsunami and kill far more people.

"Another earthquake is on its way, and all it will take to trigger it is the pressure of a handshake," says John McCloskey, a seismologist at the Environmental Sciences Research Institute at the University of Ulster in Coleraine, Northern Ireland.

Padang experienced a magnitude-7.6 earthquake on 30 September, just after 5 pm local time. Images of terrified relatives waiting to identify dead bodies, their T-shirts clutched over their noses to mask the stench, military officials stalking between bright yellow, zipped-up body bags and centuries-old Dutch colonial mansions obliterated in an instant have flooded around the world.

At first, geologists assumed this was the earthquake they had predicting for many years. "Padang has bad geology," explains McCloskey. "It sits 40 kilometres above the most earthquake-prone stretch of the interface between the Indo-Australian and Eurasian plates."

This interface has not experienced the stress relief of an earthquake for over 200 years, according to McCloskey's analysis of historical coral growth rings, which show no sign of seafloor uplift. GPS measurements of the rate of plate motion suggest that there has been around 13 metres of movement in this area over the same period. "A shallow earthquake at the plate interface off Padang is long, long overdue," says McCloskey.
Freak event

Yet the earthquake which struck this week off Padang did not occur at the plate interface, which lies 500 kilometres offshore. The epicentre was just 45 kilometres from Padang, far away from the plate interface. What's more, it originated 80 kilometres underground, far deeper than the place at which the Indo-Australian and Eurasian plates crunch together.

Further evidence comes from the orientation of the rupture caused by this week's quake. "The rupture spread in a north-south orientation, rather than east-to-west, as we would expect along the plate interface," says McCloskey.

All the clues add up to the earthquake being a freak rupture of an ancient stressed fracture zone embedded deep within the Indo-Australian plate rather than slippage at the plate interface. "What we're looking at is probably a vestigial crack left over from some distant spreading centre," says McCloskey.

So, what kind of damage will the tsunami-triggering earthquake that the geologists have been predicting near Padang inflict? McCloskey has built computer models of over 125 scenarios in which shallow, powerful earthquakes at the interface off Padang jolt the sea floor, triggering tsunamis. In most, devastating tsunamis are generated. They will reach the city about 30 minutes after the earthquake hits.

His simulations suggest that 25 per cent of tsunamis would be over 5 metres tall as they reached the coast; the highest waves would be 12 metres tall. "In reality, of course, waves will gather height and become more turbulent as they power inland, which means they could be far higher over the city," says McCloskey.
Escape routes

If the people of Padang are well prepared, then most should survive, says McCloskey. Within 30 minutes, the young and the fit should be able to reach the 10-metre elevation contour that rises 2 kilometres back from the coast, he says, which would at least protect them from waves lower than 10 metres.

However, over 100,000 people – a seventh of the city's population – are blocked from running directly to higher ground by the barbed wire-laced, 10-metre-high walls of a huge military airport.

"Padang needs to build a tunnel under that airport, because if they don't these poor people will have to run parallel to the coast for several hundred metres while the tsunami is coming at them," says McCloskey. So far, no steps have been taken to build such an exit route. "Sometimes you despair," he says.

Source : Journal references: Earth and Planetary Science Letters, DOI: 10.1016/j.epsl.2007.09.034; Nature, DOI: 10.1038/nature07572

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As we know that, preservation to build a better world environment are necessary. For instance, we should consider on energy usage. Nowadays, many researchers invent new green technology. There's a lot more to green technology than renewable energy.

From more efficient aircraft to thread made from chicken feathers, the world is awash with ingenious ideas. So we have scoured research labs and start-ups, and made some hard choices. Here you will find our pick of the best ideas to make our planet a more energy-efficient place.

Pee-n-grow

Manufacturing artificial fertiliser is a highly energy intensive process that consumes roughly 1 per cent of the world's energy supply. As odd as it sounds, using sterile, nitrogen-rich human urine instead could prevent the emission of more than 180 million tonnes of C02 each year. Urine collection systems with basement storage tanks have been built by the Stockholm Environmental Institute in more than 800 apartments in rural China, saving an estimated 20 tonnes of C02 emissions annually.

China: available now

Magnetic fridge

The two biggest consumers of electricity in the home - air conditioners and refrigerators - may soon become much more energy efficient thanks to a new method of cooling. Magnetic refrigeration subjects metal alloys to a magnetic field, causing them to cool down. Camfridge, based in Cambridge, UK, says its fridges and air conditioners will cut energy usage by around 40 per cent in comparison with conventional models.

Cambridge, UK: under development

Green machine

The world's first "virtually waterless" washing machine could soon slash the water and energy demands of dirty laundry. Prototypes developed by UK start-up Xeros rely on thousands of polarised nylon beads. These stick to dirt and gobble up stains, leaving clothes dry, and using 90 per cent less water and 40 per cent less energy than conventional washers and driers combined. If the estimated 300 million households worldwide with existing washers switched to these machines, annual C02 emissions would drop by 28 million tonnes.

Leeds, UK: available 2010

Better windows

Increase the number of layers of glass or plastic in a window and you'll save big on heating and cooling. Visionwall of Edmonton in Alberta, Canada, makes a quadruple-glazed window consisting of two layers of rigid polyethylene sandwiched between two glass layers which cuts heat loss by a factor of 4 compared with conventional double-glazed windows.

Edmonton, Canada: available now

The power of pond scum

Green algae grow like mad when fed CO2, and if turned into biofuel can yield up to 100 times the biofuel per hectare as corn, soy or sugar cane crops. Petroalgae of Melbourne, Florida, plans to license their first 2000-hectare commercial alga biodiesel plant in China next year and says the green stuff can ingest C02 straight from the smokestacks of power plants. If emissions from all the world's power plants were harnessed for alga growing and recycled as biodiesel, C02 emissions would drop by roughly 9 billion tonnes per year.

Melbourne, Florida, US: available 2010

Methane harvesting

Methane extracted from animal waste can be used as a fuel. The world's largest biogas plant in Penkun, Germany, was completed in 2008 and converts 84,000 tonnes of manure a year into usable fuel. The liquid manure, along with maize and grain, is fed into fermenters where the biomethane generates 20 megawatts of electricity and 22 megawatts of heat for the town's 50,000 inhabitants.

Penkun, Germany: available now

Superconducting grid

Up to 10 per cent of all electricity produced is lost before it even reaches the intended user due to inefficiencies in the grid. American Superconductor based in Devens, Massachusetts, has developed a superconducting wire that cuts transmission line losses threefold when chilled to -196 ° C. In 2008, the company supplied the wire for the world's first superconducting transmission line, a 600-metre, 574-megawatt cable in New York state.

US: available now

Giant microwave ovens

Known for their ability to warm food using little energy, microwaves could soon save the chemicals industry massive amounts of electricity by heating chemical reagents in much the same way. Each year, chemical manufacturers in the UK alone consume the equivalent of the electricity produced by 20 coal-fired power plants. Recent tests suggest that microwaves can cut energy requirements for heating in chemical production by as much as 90 per cent.

UK: under development

Pleasant light

Light-emitting diodes can produce the same light as incandescent or even compact fluorescent lighting for only a tiny fraction of the energy. However, the light they produce is pale and cool, which means people are reluctant to use them. UK-based company Oxford Advanced Surfaces has the answer. It is developing phosphorescent screens that convert blue-tinged LED light into the warm white light we are used to from conventional bulbs. Worldwide adoption of LEDs could cut global energy consumption for lighting in half, the company says.

UK: under development

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