Earth scientists say that from all appearances, Taiwan should be rocked periodically by devastating earthquakes. The island sits on the boundary between the Philippine Sea tectonic plate and the Eurasian plate, and geologists describe the area as one of the most seismically active in the world. Here, the colliding plates move so rapidly that they build mountains at a rate of almost 4mm per year. [Researcher Alan] Linde said that in geological terms that is almost like “growing mushrooms”. “It’s surprising that this area of the globe has had no great earthquakes and relatively few large earthquakes” [BBC News], says Linde.
Now, Linde and his colleagues think they have an explanation for Taiwan’s seismic silence in the region’s typhoons–the tropical cyclones that originate in the northwest Pacific Ocean. Their new study suggests that the typhoons passing over the island have been triggering quakes that harmlessly release fault strain over hours and days rather than destructively over seconds or minutes. And these slow earthquakes, they speculate, may be staving off a big one [ScienceNOW Daily News].
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In chunks of rock quarried from a Russian mountain range, physicists have found perfect “quasicrystals,” a type of material that researchers previously thought could only be created in a lab. Quasicrystals display ordered arrangements and symmetries but are not periodic—that is, they are not defined by a single unit cell (such as a cube) that simply repeats itself in three dimensions [Scientific American]. Instead, quasicrystals have two different geometric structures that alternate, and that are organized in ways which create complex patterns and symmetries. When such a pattern is laid out in two-dimensions, the resulting design is often called Penrose tiling.
Quasicrystals were first created in the lab in 1984, and physicist Paul Steinhardt, a coauthor of the current study, says the hunt for naturally occurring quasicrystals began about 10 years ago. “The latest issue surrounding quasicrystals has been could nature ever make them? … When we make them in the lab we try very hard to make perfect quasicrystals, but nature has no such goal” [Discovery News]. The researchers put out a call to mineralogists around the world, asking them to send in likely rock samples for testing.
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Robotic explorers on Mars get a lot of veneration for their daring feats, as well they should–but let’s not neglect the robots that are busy exploring the most inaccessible regions of our own planet. On Sunday, a robot submarine known as Nereus dove to a depth of 6.8 miles to investigate the Mariana Trench in the western Pacific Ocean. Nereus descended all the way to the deepest cranny of the trench, a spot known as the Challenger Deep, and spent more than 10 hours making observations in a spot that is deeper than Mount Everest is high.
For the expedition, the team had to build a new breed of remotely-operated submarine … which is capable of going deeper than any other while still filming and collecting samples. Sunday’s dive makes it the world’s deepest-diving vehicle [currently in operation], and the first vehicle to explore the Mariana Trench since 1998 [New Scientist]. So far, researchers have released only a single image (pictured), showing Nereus’s robotic arm scooping up sediment.
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Even before North Korea announced that it had conducted its second underground test of a nuclear weapon, scientists around the world were putting together a picture of what had happened. With a combination of seismic and radiation monitoring, scientists expect to soon have a working idea of how far the rogue nation’s nuclear program has advanced.
At 9:55 a.m. local time on Monday, two seismic monitoring stations on the Japanese coast detected seismic waves coming from the area where North Korea last tested a nuclear weapon, in 2006. The region has little natural seismic activity, and experts noted that the waves didn’t match patterns produced by earthquakes. Movements along natural fault lines transmit most of their energy through ’s-waves’, whereas explosions at a single point release a greater proportion through compressional p-waves. In the waves detected in Japan, the s-wave component was just one-fifth that of the p-wave. “You can’t say it’s impossible for a natural earthquake, but it would be very rare,” says Gen Aoki of the Japan Meteorological Agency in Tokyo [Nature News].
Experts note that the network of blast detectors intended for the Comprehensive Test Ban Treaty, which has not yet come into force, seems to have perfectly identified the explosion as a nuclear test, despite its small size. [In 1998, the U.S. Senate] rejected the CTBT partly over fears that countries could cheat, by claiming small covert weapons tests were earthquakes. The detection of the North Korean test raises hopes that the Senate will no longer be able to object [New Scientist]. But scientists had to do more than simply show that an underground explosion had sent ripples through the earth; they also have to determine how big the bomb was, and prove that the tremors weren’t caused by conventional explosives.
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A leading geothermal company has been rocked by an explosion from a well drilled deep into the earth, which was part of a system that converts the heat from buried rocks into clean, green energy. On Friday evening at the South Australian test site, a burst of pressurized water and steam blew through the well “cellar,” the 22-foot deep concrete structure set in the ground through which the deeper well is drilled.
In geothermal energy systems, wells are drilled two or three miles deep and water is circulated past the hot rocks at that depth to collect heat; the resulting steam is then used to run turbines in a power plant. Geodynamics, the Brisbane-based company that operates the South Australia well, is widely tipped as being closest to making the technology cost effective. Geodynamics holds the rights to a potential power supply of up to 10 gigawatts trapped in a 1000-square kilometre slab of hot granite deep under the town of Innamincka in South Australia [New Scientist]. But this accident is an embarrassment for the cutting-edge company. No one was injured by the blast, but the company was forced to suspend work on its first demonstration power plant, and a nearby highway was diverted.
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About 2.7 billion years ago, the primordial seas already hosted the first photosynthetic microbes, the blue-green algae that took in carbon dioxide and released oxygen into the air. But they were outnumbered by methane-producing bacteria called methanogens [that] thrived in nickel-rich seas. The high amounts of methane that this early life pumped into the environment prevented oxygen accumulation in the atmosphere because the methane reacted with any oxygen, creating carbon dioxide and water [Science News], according to one theory. Now, a group of researchers say they’ve found the trigger that allowed oxygen to build up, and therefore allowed for a profusion of oxygen-breathing life.
The secret was the concentrations of the metal nickel, according to the new study, published in Nature. The scientists found that by analysing a type of sedimentary rock known as banded-iron formations they could monitor levels of nickel in the oceans of the early Earth dating as far back as 3.8 billion years ago. They found there was a marked fall in nickel between 2.7 billion and 2.5 billion years ago [The Independent]. That stretch of time correlates with what researchers call the Great Oxidation Event, when oxygen began to take hold in the atmosphere.
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The earthquake that hit central Italy in the middle of last night, reducing some towns to rubble and killing at least 90 people, was foretold by an Italian seismologist–but his warnings were ignored, according to news reports. However, many researchers say that the seismologist’s predictions were based on inadequate evidence, and say the Italian government was right not to publicize his predictions, as they would only have spread panic.
The region felt its first tremors in mid-January. Scientists say that tremors do not necessarily indicate that a larger quake is on the way, but seismologist Giampaolo Giuliani grew increasingly concerned. He published his warnings, which received some attention; according to Italian newspapers, vans with loudspeakers drove around the town of L’Aquila one month ago telling locals to evacuate their houses. Then Giuliani, who based his forecast on concentrations of radon gas around seismically active areas, was reported to police for “spreading alarm” and was forced to remove his findings from the Internet. “Now there are people who have to apologize to me and who will have what has happened on their conscience” [Reuters], he told an Italian newspaper.
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The Alaskan volcano Mount Redoubt erupted last night with four large explosions, sending an plume of ash 50,000 feet into the air, the Alaska Volcano Observatory reported. The volcano lies only 100 miles southwest of Anchorage, Alaska’s largest city, but geologists say that current wind patterns are likely to carry the ash cloud to the north. “It looks like (Anchorage) might dodge the bullet,” Alaska Volcano Observatory geophysicist Peter Cervelli said [Anchorage Daily News]. Mudflows are also possible on nearby rivers.
The 10,200-foot Mount Redoubt last erupted during a four-month period from 1989-90…. Alaska volcanos typically explode and shoot ash upward, sometimes to 50,000 feet, high into the jet stream. An eruption of Redoubt on Dec. 15, 1989, sent ash 150 miles away into the path of a KLM jet, stopping its engines. The jet dropped more than two miles before the crew was able to restart engines and land safely at Anchorage [Fox News]. This time, Anchorage airport officials say they’ve canceled some flights, but have no immediate plans to close the airport.
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Antarctic researchers have succeeded in mapping a mountain range that is as tall and impressive as the Alps and yet invisible to the naked eye, since the entire range is hidden beneath miles of ice. The international expedition (which 80beats covered when it set off in October) used radar, gravity sensors, and other instruments mounted on airplanes to chart the contours of the mighty Gamburtsev mountains, but say the results mostly revealed new mysteries. For example, researchers expected to see a plateau formation, indicating that the peaks had been worn down over millennia. Instead, says researcher Robin Bell: “They are incredibly rough mountains — they look like alligators’ teeth” [Nature News].
“The surprising thing was that not only is this mountain range the size of the Alps, but it looks quite similar to the (European) Alps, with high peaks and valleys,” said Fausto Ferraccioli, a geophysicist at the British Antarctic Survey…. He told Reuters that the mountains would probably have been ground down almost flat if the ice sheet had formed slowly. But the presence of jagged peaks might mean the ice formed quickly, burying a landscape under up to 4 km (2.5 miles) of ice [Reuters]. Researchers say that understanding the behavior of polar ice sheets is crucial to scientists trying to predict the impacts of global warming.
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If all goes as planned, the Orbiting Carbon Observatory (OCO) will be blasted into space early tomorrow morning, and will become the first spacecraft dedicated to studying carbon dioxide, the leading greenhouse gas driving global warming. Researchers say the satellite will answer long-standing questions. Thirty billion tons of carbon dioxide waft into the air from the burning of fossil fuels each year. About half stays in the air. The other half disappears. Where it all goes, nobody quite knows…. The new data could help improve climate models and the understanding of the “carbon sinks,” like oceans and forests, that absorb much of the carbon dioxide [The New York Times].
Annual variations in the amount of carbon dioxide in the atmosphere suggest that the carbon sinks may “fill up” some years and be unable to absorb more of the gas. These fluctuations make it hard to predict future conditions, says principal investigator David Crisp, of NASA: “People are asking us to predict how much the climate will change over the next 50 years…. How can I tell you how much CO2-induced climate change there’s going to be if I don’t know how much CO2 there’s going to be in the atmosphere?” he says. Even if it were possible to predict how much CO2 humans will put into the atmosphere, “that’s still only half the puzzle,” he says. “I still need to know how much is going to be absorbed by the earth” [Technology Review].
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The devastating earthquake that killed 80,000 people in China’s Sichuan Province last May may have been triggered by a recently built hydropower dam that lies only three miles from the quake’s epicenter, some researchers are arguing. The several hundred million tons of water piled behind the Zipingpu Dam put just the wrong stresses on the adjacent Beichuan fault, [says] geophysical hazards researcher Christian Klose [Science, subscription required].
The 7.9 magnitude earthquake left more than five million people homeless. It remains a raw and emotional topic for most Chinese, and the government has been quick to quash any suggestion that Zipingpu may have been responsible for the catastrophe. Researchers have been denied access to seismological and geological data to examine the earthquake further [Telegraph]. The few researchers who have investigated the subject are now urging restraint in government plans to build more dams, but they say their advice is unlikely to be heeded.
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Natural disasters took a deadly toll in 2008, killing more than 220,000 people and causing a total of $200 billion in damages–a 50 percent increase in costs over 2007. A new report sums up the damages wrought this year by weather and geology; the deadliest disaster was the cyclone that battered Myanmar in May, killing an estimated 130,000 people and causing losses of $4 billion, and the costliest was the earthquake that struck China’s Sichuan province, killing an estimated 70,000 and causing losses of $85 billion.
The new figures come from an annual assessment of global damages by the reinsurance giant Munich Re, which offers backup policies to companies writing primary insurance policies. Reinsurance helps spread risk so that the system can handle large losses from natural disasters [AP]. Munich Re has a financial interest in understanding global weather patterns, and board member Torsten Jeworrek says the uptick in losses from natural disasters is another indication that global warming is already having widespread effects. “Climate change has already started and is very probably contributing to increasingly frequent weather extremes and ensuing natural catastrophes,” he said [BBC News].
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In a happy accident for science, a geothermal energy company drilling a borehole near the Hawaiian volcano Kilauea drilled right into a magma chamber, giving researchers a glimpse of a primal geological force. The unprecedented discovery could act as a “magma observatory,” allowing scientists to test their theories about how processes transformed the molten rock below Earth’s surface into the rocky crust that humans live on today [Wired News].
Volcanologist Bruce Marsh described the discovery at the ongoing meeting of the American Geophysical Union, saying that it’s “the first time a magma has been found in its natural habitat…. Before, all we had to deal with were lava flows; but they are the end of a magma’s life. They’re lying there on the surface, they’ve de-gassed. It’s not the natural habitat. It’s the difference between looking at dinosaur bones in a museum and seeing a real, living dinosaur roaming out in the field” [BBC News].
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An asteroid that crashed into the earth 65 million years ago may not have been the cause of the dinosaurs‘ extinction, a group of researchers are arguing. Instead, that impact may have been just a prelude to the main event, when a wave of volcanic eruptions spewed out massive clouds of sulfur dioxide, clouding the air and bringing showers of acid rain. The researchers are basing their theory on studies of an area in India called the Deccan Traps, which was convulsed with volcanic activity around 65 million years ago. At least four waves of massive eruptions spread successive sheets of thick basalt across the land for more than 500 miles, and they piled into a plateau more than 11,000 feet high over thousands of years [San Francisco Chronicle].
The new research on the Deccan Traps volcanoes, announced at the ongoing meeting of the American Geophysical Union, are the first major challenge to the asteroid theory that has dominated dinosaur extinction studies for three decades. That theory posits that a six-mile-wide asteroid slammed into Mexico’s Yucatan peninsula, creating the Chicxulub crater and cooling the climate so drastically that the majority of life forms went extinct in what’s known as the Cretaceous-Tertiary (or K-T) extinction. But geologist Gerta Keller and her colleagues argue that the impact occurred well before the massive die-offs began. By examining sediment layers, the team found that the crater impact appears to have occurred about 300,000 years before the K-T boundary, with virtually no effects to biota. “There is essentially no extinction associated with the impact,” Keller said [LiveScience].
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While Indonesia is still rebuilding following the devastating 2004 earthquake and tsunami that killed more than 130,000 people on the island of Sumatra alone, scientists are warning that several other major earthquakes are likely to occur in the region over the next decades. A new study examined the growth records of coral reefs off the coast of Sumatra, and say they show evidence of repeated bursts of earthquakes that relieve pressure on the Sunda fault. A shock in 2007 may be the beginning of a new cycle, researchers say.
Says study coauthor Kerry Sieh: “If previous cycles are a reliable guide we can expect one or more very large west Sumatran earthquakes … within the next two decades” [Reuters]. As if to illustrate the point that the Indian Ocean is seismically active, reports are coming in that a 5.9 magnitude earthquake struck last night off the coast of Sumatra; happily, there have been no reports of casualties or damages, and authorities say there is no risk of a tsunami.
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