Researchers analyzing the May 2008 Wenchuan earthquake in China's Sichuan province have found that geological stress has significantly increased on three major fault systems in the region. The magnitude 7.9 quake on May 12 has brought several nearby faults closer to failure and could trigger another major earthquake in the region.

"One great earthquake seems to make the next one more likely, not less," said Stein, who has been collaborating with Lin and Toda for nearly two decades. "We tend to think of earthquakes as relieving stress on a fault. That may be true for the one that ruptured, but not for the adjacent faults."

In 1999, a 7.4 magnitude earthquake in Izmit, Turkey, was followed four months later by an M7.1 event in nearby Duzce. The devastating December 2004 Sumatra earthquake (M9.2) and tsunami were followed by an M8.7 quake three months later.

"Because the Tibetan Plateau is one of the most seismically active regions in the world, we believe there is credible evidence for a new major quake in this region," said Lin, a senior scientist in WHOI's Department of Geology and Geophysics. "The research community cannot forecast the timing of earthquakes, and there are still significant uncertainties in our models. But the Turkey and Sumatra events indicate that one major earthquake can indeed promote another.

Researchers see it as a domino-like effect, where the movement of one piece of Earth's crust means that another piece must move up, down, or away. While the stress in the crust gets reduced in some locations, it is transferred to other faults nearby.

With earthquakes, we can roughly forecast the probability of activity over broad ranges of time, magnitude, and location, but we cannot determine the exact value for any of these."

In addition to the broad prediction of earthquake triggering, the researchers have also forecasted the rate and distribution of seismic shocks greater than magnitude 6, a prediction that they plan to test from seismic stations over the next decade.

"Earthquakes do not kill people, buildings do," said Lin, who was a high school student in China when the devastating Tangshan earthquake struck. "There needs to be widespread education in earthquake preparedness, as well as systematic inspection of buildings in these regions of heightened risk. Every new building inspection and evacuation plan could potentially save lives."

"We hope the long-term forecasting allows the Chinese government to make it a priority to mitigate future damage," Toda added. "We recommend that Chinese scientists carefully observe changes in seismicity by installing new seismometers in the region."

"The recent quake reminded us that Earth scientists have a tremendous responsibility to work on issues of societal relevance," said Lin. "We don't want to create panic, but there is legitimate cause for concern and we have a major role to play in educating the public about what we know."

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Scientists scanning the deep interior of Earth have found evidence of a vast water reservoir beneath eastern Asia that is at least the volume of the Arctic Ocean. (view image)

The discovery marks the first time such a large body of water has found in the planet’s deep mantle.

The finding, made by Michael Wysession, a seismologist at Washington University in St. Louis, and his former graduate student Jesse Lawrence, now at the University of California, San Diego, will be detailed in a forthcoming monograph to be published by the American Geophysical Union.

The pair analyzed more than 600,000 seismograms—records of waves generated by earthquakes traveling through the Earth—collected from instruments scattered around the planet.

They noticed a region beneath Asia where seismic waves appeared to dampen, or “attenuate,” and also slow down slightly. “Water slows the speed of waves a little,” Wysession explained. “Lots of damping and a little slowing match the predictions for water very well.”

Although they appear solid, the composition of some ocean floor rocks is up to 15 percent water. “The water molecules are actually stuck in the mineral structure of the rock,” Wysession explained. “As you heat this up, it eventually dehydrates.

The researchers estimate that up to 0.1 percent of the rock sinking down into the Earth’s mantle in that part of the world is water, which works out to about an Arctic Ocean’s worth of water.

Wysession has dubbed the new underground feature the “Beijing anomaly,” because seismic wave attenuation was found to be highest beneath the Chinese capital city. “China is under greater seismic risk than just about any country in the world, so they are very interested in seismology.”

Water covers 70 percent of Earth’s surface and one of its many functions is to act like a lubricant for the movement of continental plates.

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The sea was host to a plethora of anaerobic microorganisms, but there were also a few members of a newly evolved variety: cyanobacteria. These adapted bacteria were the first to use water and sunlight for photosynthesis, producing oxygen as a by-product of their metabolism.

The cyanobacteria were a struggling minority at first, but scientists believe that these new microbes began to dominate with the help of meltwater from a few glaciers scattered across the young continents. These glaciers spent centuries scraping across the Earth collecting minerals, ultimately depositing their rich nutrient payloads into the oceans. The cyanobacteria flourished in the presence of the increased minerals, and the rapidly growing population was soon venting increasingly large amounts of its poisonous waste oxygen into the environment.

The underwater oxygen began to chemically react with the abundant iron, eventually scrubbing the seas clean of the element through oxidation. This series of developments was nothing short of an ecological disaster– oxygen was poisonous to most of primitive Earth's inhabitants, and many bacteria relied on the iron as a nutrient.

Once the oceans' supply of iron was exhausted, oxygen began to seep from the sea into the air. The free oxygen they produced reacted with the air, gradually breaking down the methane which kept the Earth's atmosphere warm and accommodating. It took at least a hundred thousand years– a short duration in geological terms– but the Earth was eventually stripped of her methane, and with it her ability to store the heat from the sun. Temperatures fell well below freezing worldwide, and a thick layer of ice began to encase the oxygen-saturated planet.

Almost every living thing on Earth died as a result of this massive bacteria-induced climate change, an event known as the oxygen catastrophe.

The survivors of the oxygen catastrophe eventually adapted to consume the abundant oxygen and produce carbon dioxide. This greenhouse gas very gradually made its way into the atmosphere, increasing in concentration and nudging temperatures back into the hospitable range over millions of years.

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One man's meat is another man's poison. Just a line separates life from death.

It's got the same climate as Earth, plus water and gravity. A newly discovered planet is the most stunning evidence that life - just like us - might be out there. The discovery was announced today by a team of European astronomers, using a telescope in La Silla in the Chilean Andes.

The Earth-like planet that could be covered in oceans and may support life is 20.5 light years away, and has the right temperature to allow liquid water on its surface.

The new planet, which orbits a small, red star called Gliese 581, is about one-and-a-half times the diameter of the Earth. It is the first exoplanet (a planet orbiting a star other than our own Sun) that is anything like our Earth. Gliese 581 is among the closest stars to us, just 20.5 light years away (about 120 trillion miles) in the constellation Libra. It is so dim it can be seen only with a good telescope.

It has a mass five times that of Earth, probably made of the same sort of rock as makes up our world and with enough gravity to hold a substantial atmosphere.

Astrobiologists - scientists who study the possibility of alien life - refer to a climate known as the Goldilocks Zone, where it is not so cold that water freezes and not so hot that it boils, but where it can lie on the planet's surface as a liquid. This new planet lies bang in the middle of the zone, with average surface temperatures estimated to be between zero and 40c (32-102f). Lakes, rivers and even oceans are possible.

The surface gravity is probably around twice that of the Earth and the atmosphere could be similar to ours.

Although the new planet is in itself very Earth-like, its solar system is about as alien as could be imagined. The star at the centre - Gliese 581 - is small and dim, only about a third the size of our Sun and about 50 times cooler. The two other planets are huge, Neptune-sized worlds called Gliese 581b and d (there is no "a", to avoid confusion with the star itself).

The Earth-like planet orbits its sun at a distance of only six million miles or so (our Sun is 93 million miles away), travelling so fast that its "year" only lasts 13 of our days. The parent star would dominate the view from the surface - a huge red ball of fire that must be a spectacular sight. Its sun is an ancient star - in fact, it is one of the oldest stars in the galaxy, and extremely stable. If there is life, it has had many billions of years to evolve.

This makes this planet a prime target in the search for life. According to Seth Shostak, of the Search for Extraterrestrial Intelligence Institute in California, the Gliese system is now a prime target for a radio search.

The real importance is not so much the discovery of this planet itself, but the fact that it shows that Earth-like planets are probably extremely common in the Universe. There are 200 billion stars in our galaxy alone and many astronomers believe most of these stars have planets.

Related: Star System 'Just Right' for Building an Earth.

An Earth-like planet is likely forming 424 light-years away in a star system called HD 113766, say astronomers using NASA's Spitzer Space Telescope.

Scientists have discovered a huge belt of warm dust - enough to build a Mars-size planet or larger - swirling around a distant star that is just slightly more massive than our sun. The dust belt, which they suspect is clumping together into planets, is located in the middle of the system's terrestrial habitable zone. This is the region around a star where liquid water could exist on any rocky planets that might form. Earth is located in the middle of our sun's terrestrial habitable zone.

"The timing for this system to be building an Earth is very good," said Carey Lisse, of the Johns Hopkins University Applied Physics Laboratory, Baltimore, Md. "If the system was too young, its planet-forming disk would be full of gas, and it would be making gas-giant planets like Jupiter instead. If the system was too old, then dust aggregation or clumping would have already occurred and all the system's rocky planets would have already formed."

According to Lisse, the conditions for forming an Earth-like planet are more than just being in the right place at the right time and around the right star - it's also about the right mix of dusty materials.

Lisse says that HD 113766 does not contain any water ice, carbonates, or fragile organic materials; stuffs that makes up infant solar systems and comets.

Studies tell us that metals began separating from rocks in Earth's early days, when the planet's body was completely molten. During this time, almost all the heavy metals fell to Earth's center in a process called "differentiation." Lisse says that, unlike planets and asteroids, the metals in HD 113766 have not totally separated from the rocky material, suggesting that rocky planets have not yet formed.

"The material mix in this belt is most reminiscent of the stuff found in lava flows on Earth. I thought of Mauna Kea material when I first saw the dust composition in this system - it contains raw rock and is abundant in iron sulfides, which are similar to fool's gold," said Lisse. Mauna Kea is a well-known volcano in Hawaii.

"It is fantastic to think we are able to detect the process of terrestrial planet formation. Stay tuned - I expect lots more fireworks as the planet in HD113766 grows," he adds.

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