Tuesday, May 3, 2011
Monday, May 2, 2011
Guatemala Sinkhole

Human activity, not nature, was the likely cause of the gaping sinkhole that opened up in the streets of Guatemala City on Sunday, a geologist says.
A burst sewer pipe or storm drain probably hollowed out the underground cavity that allowed the chasm to form, according to Sam Bonis, a geologist at Dartmouth College in New Hampshire, who is currently living in Guatemala City (map).
The Guatemala City sinkhole, estimated to be 60 feet (18 meters) wide and 300 feet (100 meters) deep, appears to have been triggered by the deluge from tropical storm Agatha.
But the cavity formed in the first place because the city—and its underground infrastructure—were built in a region where the first few hundred meters of ground are mostly made up of a material called pumice fill, deposited during past volcanic eruptions.
"Lots of times, volcanic pumice originates as a flow [of loose, gravel-like particles], and because of the heat and the weight, it becomes welded into solid rock," Bonis said.
"In Guatemala City [the pumice is] unconsolidated, it's loose," he said. "It hasn't been hardened into a rock yet, so it's easily eroded, especially by swift running water."
In general, the zoning regulations and building codes in Guatemala City are poor, Bonis said, and the few regulations that exist are often ignored. That means leaking pipes could have gone unfixed long enough to create the right conditions for the sinkhole. (Related pictures: "How Humans Can Trigger Earthquakes.")
In fact, Bonis thinks calling the Guatemala City chasm a sinkhole is a misnomer—a true sinkhole is an entirely natural phenomenon. There is no scientific term for what happened in Guatemala, he said, adding that he recommends the pit be dubbed a piping feature.
Guatemala Sinkhole Not a Sinkhole
Natural sinkholes generally form when heavy, water-saturated soil causes the roof of an underground limestone cavity to collapse, or when water widens a natural fracture in limestone bedrock.
But there is no limestone beneath the section of Guatemala City where the new sinkhole appeared, at least not at the depth at which the hole formed, Bonis said.
"There may be limestone thousands of meters beneath the city, but not hundreds of meters," he said.
Instead, nature likely sped up a process set in motion by human actions. (Related: "'Mud Volcano' in Indonesia Caused by Gas Exploration, Study Says.")
Recent eruptions of several volcanoes in Guatemala covered the city in a fresh layer of volcanic ash. If this material got into the city's pipes and drains, it may have clogged the passageways, making ruptures more likely, Bonis said.
Heavy rains from tropical storm Agatha may also have overloaded underground sewage or drainage pipes, leading to a growing cavity that eventually collapsed, Bonis speculated.
The geologist added that the new sinkhole shares remarkable similarities with a sinkhole that formed in Guatemala City in 2007.
"Both of these things occurred in the same general part of town. They look the same," he said. "It's more than a coincidence, especially if they trace" any faulty pipes associated with the 2010 sinkhole to pipes near the 2007 sinkhole.
Guatemala City Sewer Inspections a Must
The danger should not have been news to officials in Guatemala City, noted Bonis, who used to work for the Guatemalan government's national geology institute.
As part of a volunteer team that investigated the 2007 sinkhole, Bonis co-authored a report warning the Guatemalan government that similar holes will very likely keep appearing unless action is taken to inspect the city's sewer system for weaknesses. (Watch video of sewer divers in Mexico City.)
The government never replied, Bonis said—possibly due to a lack of funds.
"There's a minimum of regulation, because that's money that the government doesn't have," he said.
But, he added, "there's got to be ways of inspecting the sewer system. ... These are things that have to be done."

Tuesday, April 19, 2011
Wednesday, April 13, 2011
The iPad 2 is capable of glasses-free 3D

Who would’ve thought that we’d see glasses-free3D on the iPad 2? Well thanks to some researchers at France’s Engineering Human-Computer Interaction Research Group (EHCI), they’ve found a way to recreate the whole glasses-free 3D experience. The researchers developed a hack called the Head-Coupling Perspective which takes advantage of the iPad 2′s camera to track the position and movement of the tablet user’s head and adjusts the image onscreen accordingly. With this technology, they were able to recreate the 3D effect of looking into a box with objects in it. Instead of objects popping out at you like regular 3D, we see things going inwards instead. Words aren’t going to do justice to how amazing it looks, so hit the break to check out a video demonstration:
President of the Czech Republic a pen stealer?

As just about anyone who's ever worked in an office can attest, one of life's most festering annoyances are people who don't return pens that they borrow. Now it appears as though Czech Republic President Vaclav Klaus may be one of those people, and the citizens of the nation he rules over are none too pleased about it.
You see, Klaus, whose most notable prior controversy was probably his flat rejection of climate change science—a position that he even appeared on Glenn Beck's show to tour—was caught on video coyly pocketing a ceremonial pen during a recent visit to Chile. What's more, the brazen stylus heist took place in full view of the media during a ceremony to announce a trade agreement. The video shows Klaus clearly admiring the pen, then slowly moving it into one of his jacket pockets as Chilean President Sebastian Pinera speaks to the assembled members of the media.
Now, Reuters is reporting that some Czech citizens are accusing Klaus of being a kleptomaniac. But the president's staffers claim that he had every right to take the pen—and that he was, in fact, acting entirely in line with established Czech state protocols. "We at the Prague Castle always give such a pen to delegations, along with a notepad," presidential spokesman Radim Ochvat told the news agency.
You can watch video of the incident, complete with graphics and a humorous soundtrack, below:
Subscribe to:
Posts (Atom)




