Indonesia's Infamous Mud Volcano Could Outlive All of Us

 

Unstoppable. Lusi could spew mud for decades to come.

Since it roared to life in May 2006, a mud volcano near Indonesia's coastal city of Sidoarjo has swallowed homes, rice paddies, factories, and roads, killing 15 people, displacing 40,000, and harming the livelihoods of many more. As the ongoing eruption nears its 5th anniversary, observers wonder whether it will ever stop. The answer: Not anytime soon. A new study predicts the volcano will continue spewing significant amounts of mud for another 2 decades. A second study forecasts that it could grind on as long as 87 years.

The mud volcano has inflicted a punishing blow to the region of Java island 700 kilometers east of the capital, Jakarta. Nicknamed Lusi, a contraction of lumpur (Indonesian for mud) and Sidoarjo, the volcano has so far disgorged 144 million cubic meters of mud, some of which now covers an area roughly twice the size of New York City's Central Park. Much of the mud has been diverted to a nearby river, where it has formed a new 83 hectare island and extended a natural delta. Compensation and mitigation have cost at least $767 million, according to Humanitus, a nongovernmental organization in Melbourne, Australia, that is studying the disaster's social impact. That is a fraction of the real economic toll, which is still being tallied.

Lusi may be a harbinger of disasters to come. "Like a volcanic eruption, a mud eruption is just the effect of geological activity, and I'm sure in the future another mud volcano must erupt in this region," says Soffian Hadi Djojopranoto, a geologist with the Sidoarjo Mudflow Mitigation Agency. "We need very serious research to understand this phenomenon."

Despite being the most intensely studied mud volcano ever, scientists have failed to agree on the cause of the eruption, which began in the early-morning hours of 29 May 2006. Mud suddenly started gushing out of vents 200 meters from a rig drilling an exploratory gas well. Drilling logs indicate problems with the well several hours before the eruption, and many scientists believe there was an underground blowout. Others, however, suggest that a magnitude-6.3 earthquake that occurred 2 days earlier and 280 kilometers away activated a local fault. Despite the uncertainty, the Indonesian government pressured the Bakrie family, majority owners of the drilling company and one of the country's wealthiest families, to foot most of the bill for compensation and mitigation.

Debate now centers on how Lusi's plumbing works. "The most important piece of work now is to estimate the longevity," says Richard Davies, a geologist at Durham University in the United Kingdom. That will determine if mud-handling countermeasures are sufficient. Dueling hypotheses have led to different forecasts. Davies argues that the eruption is driven by pressurized water from a deep aquifer in permeable material beneath an impermeable rock layer. He argues that the wellbore pierced the impermeable rock, allowing water to gush up and sweep overlying mud to the surface. Modeling this scenario using combinations of known quantities, such as total ejected mud volume after 1 year and 3 years and assumed parameters, including aquifer size, Davies and colleagues arrived at an estimated longevity of 26 years, published online on 24 February in the Journal of the Geological Society. They also predict that the ground around Lusi will subside up to 475 meters from its original elevation, with mud filling the crater.

Others augur that Lusi will be kicking around far longer. Michael Manga, a geologist at the University of California, Berkeley, contends that pressure and fluid originate not in the deep aquifer but in a shallower mud layer. In a paper in review, his team predicts that an ever-widening circle of subterranean mud will get sucked into the volcanic system and pushed to the surface. The model "is a new way of thinking about how eruptions work," Manga says. His team estimates a 50% chance that the eruption will last 40 years and a 33% chance that it will drag on for 87 years.

The predictions are getting a mixed reception. Peter Flemings, a geologist at the University of Texas, Austin, has not seen Manga's results, but he says his "gut feeling" is that tapping into a large permeable aquifer, as Davies proposes, would produce the volume of material spewing from Lusi. The "absolutely critical assumption," Flemings says, is the aquifer's size—and calculating that from limited data, he says, "is fraught with uncertainty." Davies's subsidence projections, meanwhile, "look big," says Heri Andreas, a geophysicist at the Institute of Technology Bandung in Indonesia. GPS surveys of ground deformation show that after an initial period during which the ground was sinking up to 4 centimeters per day, subsidence has tapered off to just several centimeters per year.

For more robust projections, says Manga, "we need more and better data." And more is at stake than scientific models. Long-term social, ecological, and infrastructure programs can't be planned "until this geological phenomenon is better understood," says Humanitus Director Jeffrey Richards. Humanitus is organizing a May symposium in Surabaya at which Richards hopes experts will forge a consensus on what studies are most likely to reveal Lusi's geological secrets. Davies would like to see a well drilled into the aquifer some distance from Lusi to measure pressures. Other options are 3D seismic surveys of the subsurface.

Numerous efforts to plug the volcano have failed. Fortunately, the mud flow is now manageable, says Djojopranoto. After peaking at 180,000 cubic meters per day in early 2007, the rate has tapered to 10,000 cubic meters per day. A system of 6- to 7-meter-high earthen dikes encloses some 700 hectares of ponds where mud and water is collected and then pumped into the Porong River, where it is adding to a natural delta downstream. The impact on the Porong has been minimal, given that it historically carried heavy sediment loads from magmatic volcanoes upstream, Djojopranoto says.

Environmentalists claim that authorities are understating some of Lusi's ill effects. Studies by nongovernmental organizations in 2007 indicated that high sedimentation was smothering marine life, particularly bottom-dwelling creatures like snails, says Pius Ginting of the Indonesian Forum for Environment. An ongoing concern, he says, is the mud's toxicity, which he claims is laden with carcinogenic polyaromatic hydrocarbons—a contention that Djojopranoto says has never been independently verified.

In Lusi's vicinity, the mitigation bureau has rerouted roads and resettled most families. Mud volcano tourism is providing income, says Djojopranoto, but "not enough to revive the economy." Even after the eruption ends, Lusi may erupt periodically or ooze mud for centuries. "On east Java, we have mud volcanoes that have been active for hundreds of years," Djojopranoto says. None, however, compare in size, in societal harm, or in the puzzles that Lusi continues to present to scientists.

Source : http://news.sciencemag.org/sciencenow/2011/02/indonesias-infamous-mud-volcano-.html?ref=hp

More Evidence Against Dark Matter?

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Nothing hidden. Without dark matter, MOND neatly explains the relation between the mass of visible matter in a gas-rich galaxy like this one and the galaxy's rotation speed.

Thousands of physicists, astrophysicists, and astronomers are searching for dark matter, mysterious stuff whose gravity seems to hold the galaxies together. However, an old and highly controversial theory that simply changes the law of gravity can explain a key property of galaxies better than the standard dark-matter theory, one astronomer reports. That claim isn't likely to win over many skeptics, but even some theorists who favor the standard theory say the analysis hands them a homework problem they should solve.

"The standard theory should explain this, and it doesn't yet. That's fair to say," says Simon White, a cosmologist at the Max Planck Institute for Astrophysics in Garching, Germany, who was not involved in the current analysis.

In 1933, Swiss astronomer Fritz Zwicky suggested the existence of dark matter when he found that the galaxies in a particular cluster swirl about each other too fast to be bound by their gravity alone. In the 1970s, American astronomer Vera Rubin and others discovered that the stars at the edges of individual galaxies also appear to move too fast to be held by the gravity of the stars in the center. Those outer stars ought to move more slowly than the ones circling closer in—just as Jupiter orbits the sun more slowly than Earth. Instead, the speed of the stars generally increases with the distance from the galactic center, eventually flattening out at a maximum value. That observation seemed to clinch the case for some sort of dark matter.

Or did it? In 1983, Mordehai Milgrom a physicist at the Weizmann Institute of Science in Rehovot, Israel, found that he could explain the so-called galaxy rotation curves without dark matter if he simply assumed that on the galactic scale, dynamics and gravity worked a bit differently from what Isaac Newton postulated. Specifically, Milgrom assumed that for very small accelerations, the square of the acceleration, not just the acceleration, is proportional to the gravitational force.

For the past 28 years, Milgrom's idea, known as Modified Newtonian Dynamics (MOND) has generated a long-simmering debate. Many researchers argue that ever more evidence from clusters of galaxies, the largest scale structure of the universe, and the afterglow of the big bang points to the existence of dark matter. Still, a few researchers counter that when they look at the details, MOND does a better job—at least on the galactic scale.

Now, in the latest shot from the MOND side, Stacy McGaugh, an astronomer at the University of Maryland, College Park, reports that MOND can explain an observed correlation between the mass and the rotation speed of galaxies—that is, the speed of those outer stars—called the baryonic Tully-Fisher relation. MOND researchers had tried to do this before, but for their models to work, they had to make an untested assumption about the relationship between a star's mass and the amount of light it puts out. That assumption introduces a large uncertainty, weakening the argument.

To avoid that problem, McGaugh gathered data from various sources on 47 galaxies that contain more hydrogen gas than stars. The mass of the gas can then be estimated directly. McGaugh made a plot of visible mass versus rotation speed for the galaxies. He then plotted the prediction that comes straight out of MOND in a few lines of algebra. The MOND line went right through the data. "You draw the line and the data fall right on it," McGaugh says. "No muss, no fuss." He reports the result in a paper in press at Physical Review Letters.

Crucially, McGaugh finds very little scatter in the data—just what would be expected if the mass of gas and stars was directly determining the rotation speed. It's not clear exactly what dark-matter models would predict, McGaugh says. However, such models make no strong connection between the amount of visible matter and the rotation speed. Indeed, galaxies with the same mass of dark matter can have different numbers of stars. So it would be surprising if dark-matter models yielded such a tight correlation.

"I think the data are good, and the fact that MOND fits is striking," says White, who has worked extensively on simulating the evolution of the universe. "I think Stacy is right in holding this up and saying [to dark-matter modelers], 'Look at this [correlation]. Go see if you can explain it.' " Still, White says, dark matter can explain the variations in the afterglow of the big bang and other cosmological data with which MOND struggles.

But whether MOND is right may be beside the point, says Jerry Sellwood, a theoretical astrophysicist at Rutgers University in New Brunswick, New Jersey. "The real strength of Stacy's paper is that it points to something that can't be explained in cold dark matter, irrespective of whether MOND is right." At the least, Sellwood says, McGaugh deserves credit for keeping others honest about what their models can do.

Souce : http://news.sciencemag.org/sciencenow/2011/02/more-evidence-against-dark-matte.html?ref=hp

East Coast Winds Would Support a Stable Power Grid

Blowin' in the wind. Electricity output from individual turbine farms can vary greatly (colored lines), but linking them up along whole coastlines can smooth out total power production (thick black line).

Individual wind turbines and even whole wind farms remain at the mercy of local weather for how much electricity they can generate. But researchers have confirmed that linking up such farms along the entire U.S. East Coast could provide a surprisingly consistent source of power. In fact, such a setup could someday replace much of the region's existing generating capacity, which is based on coal, natural gas, nuclear reactors, and oil.

In terms of potential, wind-energy resources are tremendous. One estimate puts it at nearly five times as much as the world's entire existing electricity demand. And for environmentalists and anticarbon advocates, wind offers an energy source that does not require drilling, mining, or enriched uranium—and its carbon footprint is essentially zero.

But wind is erratic. A region might get gale-force winds one day and dead calm the next. To balance things out, engineers have proposed linking up wind farms to take advantage of wind variability across a wider area. But until now, no one had ever quantified whether meteorological conditions would justify such a linkup.

In the new study, energy policy analyst and electrical engineer Willett Kempton of the University of Delaware, Newark, and colleagues did just that. "Instead of just looking at the statistics of connecting turbines," he says, "we also decided to look at the meteorology." First the researchers chose a region known for its relatively constant winds. They compiled 5 years of wind data from 11 offshore weather-monitoring stations buoyed along 2500 kilometers of the East Coast. They estimated how much power offshore wind farms could produce if they had been placed at the same locations as the monitoring stations—which would be the case under current wind-farm configurations. Then they calculated the combined power output of the farms if they were all connected into a single grid.

As the team reports online today in the Proceedings of the National Academy of Sciences, at no time during the 5-year span of the study did the winds die down completely along the hypothetical grid. That means it would have been possible for the hypothetical offshore wind-power grid to generate electricity continuously for all of that time. Moreover, Kempton explains, linking the wind farms showed "a tremendous amount of smoothing" of power output. Farms located, say, in the Northeast might be operating at full tilt under gale-force winds, while the southeastern portion of the grid languishes under sunny skies and tepid breezes. As the wind data showed, he added, the quick swings between high- and low-power generation periods that are characteristic of individual wind farms slowed down dramatically within the simulated grid, taking days instead of hours or even minutes. By creating a wind-power grid, he says, "you can make a rapidly changing and unsteady source of power a slowly changing and stable one."

This is the first time a study has demonstrated that offshore East Coast wind energy can provide "a relatively reliable supply of smooth power," says environmental engineer Mark Jacobson of Stanford University in California. The findings are "important," he says, because the wind resources of the region are "tremendous and could theoretically supply all U.S. electric power demand."

The findings are "amazing," agrees Cristina Archer, a specialist in wind energy meteorology at California State University, Chico. Kempton's team shows "that an uninterrupted power supply from winds along the most populated and most energy-demanding coastal area in the country, and perhaps in the world, is possible."

Source : http://news.sciencemag.org/sciencenow/2010/04/east-coast-winds-would-support-a.html?ref=hp

Can Geoengineering Halt Sea-Level Rise?

Extreme. Launching trillions of tiny lenses into space to block the sun may halt sea-level rise.

Launching sun-blocking aerosols into space or growing vast new forests could help cool the planet, but such "geoengineering" schemes will have a tough time stopping sea-level rise by the end of the century, a new study suggests. More extreme schemes could help, however, as might combining geoengineering with drastic cuts in greenhouse gas emissions.

Scientists hope that geoengineering could, in addition to curbing global warming, stop sea-level rise by cooling the planet enough to slow glacier melting and flow. Rising waters are a threat to coastal cities around the world—and even with strict cuts in emissions, scientists believe sea levels will rise significantly by 2100.

The new study is the first to estimate how much geoengineering might reduce sea-level rise, says study leader John Moore of Beijing Normal University in China. According to a model developed by Moore and colleagues, without geoengineering, sea levels would rise between 50 to 100 centimeters over the next century. Relatively modest geoengineering schemes would help only a bit. One of the these schemes would involve mimicking large volcanic eruptions, like the 1991 eruption of Mount Pinatubo—the second largest of the past 100 years—which shot sunlight-blocking sulfate aerosols high into the atmosphere. Moore's team found that pumping a Pinatubo-worth of sulfates into the stratosphere every 4 years would limit sea-level rise to about 30 centimeters. A similar effect would be achieved by combining biomass power plants that capture their CO₂ with vast new forests and enormous quantities of biochar—a form of charcoal that locks away carbon from the air.

To cut sea-level rise to zero, Moore says researchers would need to combine these approaches with drastic cuts in greenhouse gas emissions—or employ "extreme geoengineering" strategies. These could include injecting aerosols at Pinatubo levels into the atmosphere every 18 months instead of every 4 years, or launching trillions of tiny lenses into space, the team reports online this week in the Proceedings of the National Academy of Sciences.

These extreme geoengineering approaches are potentially hazardous, however, as blocking sunlight can alter rainfall patterns and even damage the ozone layer, Moore says. "I think that sucking CO₂ out of the atmosphere is the best way to stop sea-level rise before 2100." That could be accomplished with the biomass power plants and new forests considered in the study, or by massively scaling up CO₂ removal techniques currently deployed in spacecraft and submarines.

Geochemist Ken Caldeira of the Carnegie Institution for Science in Stanford, California, says the findings are "worthy" but that it's too early to decide which approach is best. "Significantly more study is needed before we are justified in making general claims." Every geoengineering method has pros and cons, Caldeira says, and involves a tradeoff of costs, risks, and effectiveness.

Source : http://news.sciencemag.org/sciencenow/2010/08/can-geoengineering-halt-sea-leve.html?ref=hp