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Through the release of CO2 and other gases, earthquakes and volcanoes do more than simply relieve planetary flatulence. Without such greenhouse gases in our atmosphere to hold in some of the sun’s radiant heat, the planet would in short order become frigidly inhospitable to most known forms of life.
But, no matter its importance to life on this planet, what’s going on deep within the Earth remains the subject of speculation and cause for intense studies for now.
“Unfortunately, we can’t visit the core of the Earth, below the mantle, or the mantle itself,” Wu said. To do so would require the ability to “drill down” either by means of a bore hole or penetrating technology to a depth of more than 2,900 kilometers, more than five times deeper than the TAIGE R survey will reach
A major phase of the TAIGE R project experiments will take place this spring. It will involve more than 1,000 seismometers to monitor 14 land explosions set off at depths of about 60 meters. A host of sensors and seismometers will also be deployed from the American research ship R/V Marcus Langseth for marine experiments off the coast of Taiwan in the spring of 2009. This phase will involve blowing huge bubbles near the ocean surface and monitoring the seismic waves they create.
Far outpacing the omnipresent forces of erosion, the peaks of Taiwan are rising 2 or 3 centimeters a year in places. That’s quite the growth spurt in geological terms, and because the mountain-building process is so active there, Taiwan has been the focus of many prior and current international geological studies.
“In Taiwan, land keeps pushing up, and gravity pulls on it, and it comes down. So it is a very lively place in that sense,” Wu said. Landslides are commonplace, and residents take them in stride.
“You certainly have to be careful where and how you build roads. I’ve come across several fresh landslides right after they had closed roads and my Taiwanese colleagues would say, ‘Oh don’t worry, in another two hours the road will probably be open again,’” Wu said.
The high-resolution images provided by the TAIGER survey are expected to result in the most detailed map ever of Taiwan and its mountains. Imaging is expected to extend from 12,900-foot mountain peaks to the Earth’s upper mantle some 370 miles underground.
But Wu and others believe that all the commotion at Taiwan’s surface is just an indication of far deeper forces. The TAIGER project will afford a “rare geological test of theory” that ultimately could help architects and engineers build safer structures, Wu said.
“Mountain building is not only in the crust, but also in the upper mantle, probably driven by forces that might be much deeper than previously understood,” Wu said. “My view is that one problem that keeps us from predicting earthquakes is that we don’t really understand all the processes in question. We know the crust is moving and strain is accumulating and eventually it will break. But when does it start to break and where are the faults? Some are probably too deep to be probed, but some are shallow enough for us to image.”
By providing a better understanding of the forces involved in mountain building and the earthquakes to which that process gives rise, Wu also hopes that TAIGER might give scientists a better idea about which major faults to monitor for the purpose of early warning for earthquakes. For some potentially hazardous faults in Taiwan, a warning of 40 seconds or more for a metropolitan area may be possible.
“Some people might ask the question, ‘What is the use of this information if we will only know 40 seconds before the earthquake?’
“Maybe this would not be so useful for city dwellers who face a congested highway as they try to evacuate the city,” Wu said. “But on the other hand, even in cities, high-speed transport could be stopped, people could evacuate tall buildings and many businesses, particularly in the semi-conductor industry, which is very big in Taiwan, could have enough time to shut everything off. If you have tens of minutes, you can do all kinds of things. And if we could eventually predict within a few days of an earthquake, then we could effectively prevent loss of life.”
— Susan E. Barker
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