Eyeing Earth from cloud top to seabed

Earth scientists are beginning to live what they once considered an impossible dream. They are establishing systems to monitor our entire planet continuously, from the outer fringes of the atmosphere to the deepest seabed. They even are beginning to track the grinding of rock upon rock that generates earthquakes.

They are linking communications systems to shunt these data to whomever can work them into useful knowledge. Often this now can be done in minutes instead of hours, days, or weeks. An unprecedented cooperation is developing among nations so that earth scientists will no longer look at our planet in the old, fragmented way.

These technological developments have brought humanity to the brink of "great opportunities," said American Geophysical Union president John Orcutt at a meeting of the group last week in San Francisco. A few of many instances of such opportunities presented at the meeting illustrate this.

Scientists at the Scripps Institution of Oceanography in La Jolla, Calif., where Dr. Orcutt is deputy director, have developed a way to use the worldwide seismic observing network to image earthquake ruptures. Within 30 minutes or less, they can trace the entire crustal rupture that produces a quake anywhere in the world. This information is much more valuable than merely pinpointing the quake epicenter. "This is important for tsunami warning systems in which you need to know a path - not just the original location - of an earthquake," explains Scripps scientist Peter Shearer.

Meanwhile, in North America, the EarthScope project is establishing a continent-wide network of GPS locators, seismographs, and other instruments to study what's happening below the crust.

The network, which will cover the United States and reach into Canada and Mexico, is beginning to track the interaction of the two great crustal plates that respectively carry the Pacific Ocean and the continent. Its prime feature is an observatory in Parkfield, Calif., which has placed instruments nearly two miles deep into the Earth right up against the San Andreas fault to record every creep, rattle, and grind. The goal is "to get into the heart of this [earthquake] machine" and test scientists' speculations as to how it works, says William Ellsworth, a geologist with the US Geological Survey in Menlo Park, Calif.

Networks of satellites already on orbit or soon to be launched are beginning to provide detailed observations of the workings of the atmosphere, ocean, and continental crust over the entire planet. These data are shared globally through an unprecedented cooperation among 58 nations called the Global Earth Observation System of Systems.

Orcutt noted that it will take high-volume high-speed communications to make the most of such sharing. Such a system, now under development, will shunt data a thousand times faster than current "high speed" broadband Internet links. Orcutt added that a strong commercial incentive exists to develop this system. It would allow movie studios, for example, to transmit a digital motion picture directly to theaters, where it could be shown in real time.

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