Using a novel device that simulates earthquakes in a laboratory setting, a Los Alamos researcher and his colleagues have shown that seismic waves - the sounds radiated from earthquakes - can induce earthquake aftershocks, often long after a quake has subsided.
The research provides insight into how earthquakes may be triggered and how they recur.
In a letter appearing today in Nature, Los Alamos researcher Paul Johnson and colleagues Heather Savage, Mike Knuth, Joan Gomberg, and Chris Marone show how wave energy can be stored in certain types of granular materials - like the type found along certain fault lines across the globe - and how this stored energy can suddenly be released as an earthquake when hit by relatively small seismic waves far beyond the traditional "aftershock zone" of a main quake.
Science & Technology
With over 3.5 million registered users (up from 600,000 two years ago), StumbleUpon has left the techie niche and has become mainstream. But unlike Google which makes its billions from helping you find what you're looking for, StumbleUpon helps you discover content that you may not be looking for but will probably find interesting.
Eleven previously unknown animal and plant species have been discovered by scientists in a remote forest region that they say is like "paradise".
Three salamanders with ballistic tongues were among the finds that astounded researchers recording wildlife in the forest in Central America.
In addition to the new species, the researchers also found 5,300 previously catalogued species in the cloud forest in La Amistad National Park in Costa Rica. The area is one of the least spoilt in the world, after its human inhabitants deserted it centuries ago.
The remoteness of the park and the lack of human interference there have allowed it to flourish as one of the most ecologically valuable ecosystems in the world.
Three salamanders with ballistic tongues were among the finds that astounded researchers recording wildlife in the forest in Central America.
In addition to the new species, the researchers also found 5,300 previously catalogued species in the cloud forest in La Amistad National Park in Costa Rica. The area is one of the least spoilt in the world, after its human inhabitants deserted it centuries ago.
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The remoteness of the park and the lack of human interference there have allowed it to flourish as one of the most ecologically valuable ecosystems in the world.
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| Plate tectonics is driven by heat flowing from the Earth's interior, and a stoppage would slow the rate of the Earth's cooling, just as clamping a lid on a soup pot would slow the soup's cooling. |
Plate tectonics, the geologic process responsible for creating the Earth's continents, mountain ranges, and ocean basins, may be an on-again, off-again affair. Scientists have assumed that the shifting of crustal plates has been slow but continuous over most of the Earth's history, but a new study from researchers at the Carnegie Institution suggests that plate tectonics may have ground to a halt at least once in our planet's history-and may do so again.
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| The TCS system is compatible with the NATO UAS control standard and is capable of all levels of flight and sensor control of NATO standard UASs. |
Raytheon recently completed initial testing of the Tactical Control System's (TCS) command and control capabilities for the U.S. Navy's MQ-8B Fire Scout unmanned helicopter. The testing was conducted Dec. 15, 2007, at the Webster Field annex, Naval Air Station, Patuxent River, Maryland.
The most intense meteor shower of the year hits Earth tonight. If the skies are clear and you live at high northern latitudes, then you could see dozens of Quadrantid meteors streaking over the pole.
Or you might spot a plane full of astronomers racing northward, trying to find out how this unusual meteor shower was created, and whether it is the shrapnel of a celestial explosion witnessed in the 15th century.
Like other meteor showers, the Quadrantids appear when Earth moves through an interplanetary stream of debris, which hits the upper atmosphere at more than 40 kilometres a second, vaporising to become the brilliant trails we see as shooting stars.
Or you might spot a plane full of astronomers racing northward, trying to find out how this unusual meteor shower was created, and whether it is the shrapnel of a celestial explosion witnessed in the 15th century.
Like other meteor showers, the Quadrantids appear when Earth moves through an interplanetary stream of debris, which hits the upper atmosphere at more than 40 kilometres a second, vaporising to become the brilliant trails we see as shooting stars.
LIVERMORE, Calif. -- U.S. troops blew up enemy bridges with explosives in World War II to slow the advance of supplies or enemy forces.
In modern times, patrollers use explosives at ski resorts to purposely create avalanches so the runs are safer when skiers arrive.
Other than creating the desired effect (a destroyed bridge or avalanche), the users didn't exactly know the microscopic details and extreme states of matter found within a detonating high explosive.
In fact, most scientists don't know what happens either.
In modern times, patrollers use explosives at ski resorts to purposely create avalanches so the runs are safer when skiers arrive.
Other than creating the desired effect (a destroyed bridge or avalanche), the users didn't exactly know the microscopic details and extreme states of matter found within a detonating high explosive.
In fact, most scientists don't know what happens either.
Scientists have developed a machine which is capable of reading our mind and revealing our most private thoughts.
American researchers from Carnegie Mellon University in Pittsburgh, found that, with the aid of a sophisticated scanner and computer programme, they were able to determine how the brain lights up when thinking about different subjects.
American researchers from Carnegie Mellon University in Pittsburgh, found that, with the aid of a sophisticated scanner and computer programme, they were able to determine how the brain lights up when thinking about different subjects.
What part of you is only 1% to 3% of your body's mass, yet uses 20% of all the oxygen you breathe? Your brain! Here are ten more brain facts:
- Your brain needs a continuous supply of oxygen. A 10 minute loss of oxygen will usually cause significant neural damage. Cold can lengthen this time, which is why cold-water drowning victims have been revived after as much as 40 minutes - without brain damage.
- Your brain uses a fifth of all your blood. It needs it to keep up with the heavy metabolic demands of its neurons. It needs not only the glucose that is delivered, but of course, the oxygen.
- Your brain feels no pain. There are no nerves that register pain within the brain itself. Because of this, neurosurgeons can probe the brain while a patient is conscious (what fun!). By doing this, they can use feedback from the patient to identify important regions, such as those used for speech, or visualization.
- Your brain needs a continuous supply of oxygen. A 10 minute loss of oxygen will usually cause significant neural damage. Cold can lengthen this time, which is why cold-water drowning victims have been revived after as much as 40 minutes - without brain damage.
- Your brain uses a fifth of all your blood. It needs it to keep up with the heavy metabolic demands of its neurons. It needs not only the glucose that is delivered, but of course, the oxygen.
- Your brain feels no pain. There are no nerves that register pain within the brain itself. Because of this, neurosurgeons can probe the brain while a patient is conscious (what fun!). By doing this, they can use feedback from the patient to identify important regions, such as those used for speech, or visualization.
LIVERMORE, Calif. -- Samples of the material picked up during the NASA Stardust mission indicate that parts of the comet Wild 2 actually formed in an area close to the sun.
