1. 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.

2. 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.

3. 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.

4. 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.