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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The explosion of a volcano located in present-day China might have caused a mass extinction 260 million years ago, adding more evidence that volcanoes might have been to blame for some of the world’s most catastrophic die-offs. Because the eruptions occurred in a shallow sea the researchers were able to study both the volcanic rock and the overlying layer of sedimentary rock containing fossilized marine life [AP], giving researchers a better picture of how the explosion altered the balance of life.
The injection of hot lava in a sea would have produced a massive cloud formation that could spread around the world, cooling the planet and producing acid rain [AP], according to the study, which was published in Science and led by paleontologist Paul Wignall. Based on analysis of the volcanic and sedimentary rock at the eruption site, the scientists hypothesized that ash and lava spewed from a sea covering the volcano, showering plants and animals with atmospheric carbon. “When fast flowing, low viscosity magma meets shallow sea it’s like throwing water into a chip pan there’s spectacular explosion producing gigantic clouds of steam” [Telegraph], says Wignall.
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West Africa has a history of severe, prolonged “mega-droughts,” according to a new study, and researchers say that another one is inevitable, although they can’t say when it might occur. Says lead researcher Tim Shanahan: “It’s disconcerting – it suggests we’re vulnerable to a longer-lasting drought than we’ve seen in our lifetime…. If the region were to shift into one of these droughts it would be very difficult for people to adapt; and we need to develop an adaptation policy” [BBC News].
The study, which examined sediment samples on a lake bottom to trace the climate history back 3,000 years, reveals that the infamous 1970s drought of the African Sahel region, which lasted several decades and killed more than 100,000 people, was actually a “minor” event…. “What’s disconcerting about this record is that it suggests the most recent drought was relatively minor in the context of the West African drought history” [New Scientist], says Shanahan. The researchers found that decades-long droughts similar to the 1970s event occur every 30 to 60 years, but that even more severe, century-long droughts have reoccurred as well. The most recent mega-drought began in 1400 and lasted until 1750, during which time forests grew up in dry lake beds.
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Researchers have found that droughts kill pine trees faster when temperatures are higher, a piece of information that bodes ill for forests in a warmer world. A new study examined the effect of dry conditions and temperature on the pinion pine, a hardy evergreen that lives in the American Southwest, and found that “together, drought and temperature can kind of provide a double whammy,” said David Breshears, a researcher involved in the experiment [Reno Gazette Journal].
Researchers could isolate the impact of heat due to the unusual environment where the experiment took place. The study was conducted in Biosphere 2, a glass and steel laboratory that includes recreations of the planet’s savannas, deserts, oceans and forests…. Half the pinions studied were kept in normal temperatures, the others in an environment 7 degrees warmer. Some trees in each group were then deprived of water to simulate droughts common in the past [AP]. Trees subjected to higher temperatures died five times faster than the other trees, suggesting that even short droughts could produce widespread tree mortality in a warmer climate [AP]. The study was published in the Proceedings of the National Academy of Sciences.
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Next month, meteorologists will fan out across the U.S. prairie to chase storms, and to try to catch tornadoes in the act of forming. Pulling together truck-mounted radar, UAVs, wind meters bolted to car roofs, webs of stationary sensors and a generous dash of adventure, 100 scientists with 40 vehicles will spend a month tracking the huge formations of clouds called supercells that occasionally spawn twisters. From a mobile field command vehicle, this army of scientists will conduct a data-gathering war on nature’s baddest storms [Wired].
This ambitious effort from the National Oceanic and Atmospheric Administration (NOAA) and the National Science Foundation (NSF) aims to discover exactly what turns a fierce thunderstorm into a twister. The project, called Vortex2, follows the first Vortex project in the mid-1990s, which documented the entire life of a tornado for the first time. The new project will include “more detailed sampling of a storm’s wind, temperature and moisture environment, and lead to a better understanding of why tornadoes form — and how they can be more accurately predicted” [AP], says the NSF’s Stephan Nelson.
The urgent need for better prediction was demonstrated just last night, when a tornado ripped through the Arkansas town of Mena, killing three and demolishing houses, churches, a factory, and even the town’s city hall.
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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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Tropical rainforests are often considered one of the world’s greatest protections against global warming, as the lush forests can absorb huge amounts of carbon dioxide, the main greenhouse gas behind climate change. But shifting weather patterns can transform the rainforest from an ally to a hindrance: According to an international study, a 2005 drought in the Amazon rainforest killed trees and released more greenhouse gas than the annual emissions of Europe and Japan [Reuters].
Researchers say that the 2005 drought slowed the growth of trees, thereby slowing their absorption of carbon dioxide, and also killed off trees, which emitted carbon dioxide as they rotted. Researchers say that if global warming brings more dramatic weather patterns and dryer conditions to the Amazon, as some climate models predict, the rainforest could even accelerate global warming. Says lead researcher Oliver Phillips: “For years, the Amazon forest has been helping to slow down climate change. But relying on this subsidy from nature is extremely dangerous…. We cannot take this carbon sink for granted” [CBC].
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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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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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Two groups of geologists have found evidence that the Indian Ocean tsunami that devastated coastal towns in Southeast Asia in 2004 wasn’t the first massive wave to pummel those shores, but the last tsunami of equivalent size occurred about 600 to 700 years ago. That long gap might explain how enough geological stress built up to power the huge undersea earthquake that launched the killer waves four years ago, researchers said [AP].
One group of researchers took sediment samples on a barrier island off the west coast of Thailand, while the other group dug into the soil in a northern region of Sumatra. The surge of a tsunami brings with it a great deal of sediment that rushes inland; the bigger the tsunami, the deeper and further inland the layer of sediment it leaves behind. In locations where those deposits aren’t disturbed by wind or running water, they can be used as a historical record of tsunami after more layers are added later [BBC News].
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In a new study, researchers looked at the role of cyclones in Earth’s carbon cycle. They found that cyclones (an umbrella term for hurricanes, typhoons, and tropical storms) can transfer terrestrial organic carbon, in the form of plants, soil, and fossils, to the bottom of the oceans and prevent it from entering the atmosphere. In just a few days a single typhoon can dump the same amount of carbon to the bottom of the ocean as an entire year of rain. The storms do this by ripping mud and decaying vegetation off the land, and flushing it down rivers in huge floods and out to sea [New Scientist].
The study, published in Nature Geoscience [subscription required], conducted on the LiWu river in Taiwan, focused on how cyclones sequester carbon rather than how much carbon they bury. Nevertheless, the researchers warn that the amount of carbon sequestered by cyclones is a pittance compared to the amount of carbon generated by human activity. “The current amount of carbon dioxide building up from manmade sources is about 100-1,000 times faster than this carbon (burial) from the interaction between the cyclones, erosion and forests,” said Robert Hilton of Cambridge University who was one of the authors. “In terms of the manmade carbon cycle this is not going to save us. But it illustrates that the earth has natural ways of dealing with carbon dioxide,” he said [Reuters].
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The May earthquake in China’s Sichuan province that killed 70,000 people may lead to further destruction. According to a new seismic study, the magnitude 7.9 earthquake in May increased the stress on nearby faults, and therefore heightened the risk of further quakes. Stress on the nearby Kunlun, Xianshuihe and Min Jiang faults has increased, they say, doubling the risk that one of them will unleash a magnitude 6.0 or 7.0 tremor in the next decade [Discovery News].
Those three nearby faults are now under more stress because of a domino-like effect where the movement of one piece of Earth’s crust forces another piece to move up, down and away, geophysicists reported. “One great earthquake seems to make the next one more likely, not less,” said [study coauthor] Ross Stein of the U.S. Geological Survey. “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” [Reuters].
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In the destructive heart of hurricane season, climate scientists have come out with some alarming news: the most powerful storms have gained wind strength over the past 25 years as a result of gradually warming ocean waters, and global warming is likely to continue that trend. It’s hardly welcome news, as Gulf Coast residents are still recovering from this week’s close call with Hurricane Gustav and Caribbean islanders are warily eyeing several new tropical storms gaining strength over the Atlantic.
The new study is likely to renew the debate over global warming’s effect on major storms: [T]here has been controversy about whether these hurricanes will get more intense and numerous, with many claiming the data are not good enough to discern a real trend upwards in recent years…. Today’s study, by Prof James Elsner of Florida State University, concludes that the strongest tropical cyclones – the general term for intense storms such as hurricanes and typhoons – are getting stronger, with the greatest increase recorded in the North Atlantic and northern Indian oceans [Telegraph].
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In a congressional hearing yesterday, a supplier of the “FEMA trailers” used after Hurricane Katrina admitted that the company has known for years that the trailers contained dangerous levels of formaldehyde. But the chairman of Gulf Stream Coach said his company failed to disclose to Hurricane Katrina evacuees or the government its internal findings that formaldehyde in some units exceeded a federal health standard by as much as 45 times in 2006 [Washington Post].
Gulf Stream received over $500 million from the Federal Emergency Management Agency (FEMA) for 50,000 trailers that housed displaced Gulf Coast residents after the devastating 2005 hurricanes. But Gulf Stream chairman Jim Shea deflected blame for the evacuees’ chemical exposure to FEMA, saying that the agency turned down the company’s offer to conduct thorough tests on the trailers.
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