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Toward Real-Time Earthquake Warnings


Exciting progress is being made in real-time earthquake warnings. It's an old idea, that you could hook up a radio to a seismograph and have it send you a message when it feels a quake. You'd have a useful amount of time to react—even five seconds would be enough for a classroom of kids to get under their desks, or for you to save that file you're working on. And with 30 seconds' warning, you could pull a fire engine out of its garage, start up your hospital's emergency power, do quick computer backups and prepare in many other ways.

The First Crude System

In 1989, in the days after the October 17 World Series quake in the San Francisco Bay area, Bill Bakun of the U.S. Geological Survey set up just such a system to alert workers in Oakland, 100 kilometers away, of aftershocks as they occurred. With 20 seconds of warning, workers in the wreckage of the collapsed Cypress Viaduct could get out of harm's way. (This background document contains the story.)

That concrete example got a lot of people thinking. Authorities in Mexico, for example, rigged up a simple alert system in 1993 that would set off alarms in Mexico City after a major earthquake off the coast of Guerrero province. Romania is building a system to warn the capital of Bucharest. And the Japanese early warning system, launched in 2007, was well displayed during the great March 2011 earthquake and its aftermath.

Once the basic idea is demonstrated, though, there are many questions that follow. Exactly who do you notify, and how? And what happens after that? And how complicated is it to monitor a whole region like Southern California, not just one locality like Guerrero, and alert the particular cities near the quake, not just one distant target city?

Pioneers in California

Southern California is a special case, where the Northridge quake in January 1994 caused some $20 billion in damages. That year an ambitious project called TriNet was launched, a joint effort of the USGS, Caltech, and the state of California to expand the network of digital seismometers in Southern California, quakeproof its data links, and tie it to the emergency-response providers. An early-warning system was part of the plan, although that was ultimately not constructed. But take heart anyway, because the part they did build will do more good.

Already in place is a system that detects an earthquake within one second and specifies its location and magnitude within 20 seconds. It displays maps of significant quakes and the extent of shaking within minutes of the event. And the Live Internet Seismic Service (LISS) is in operation displaying real-time seismograms from around the world.

Right now, emergency officials in California can have immediate pictures of what area has been shaken and how strongly, allowing them to rush help to where it's needed most. A robust Internet setup will handle up to a million hits per hour to inform the world what is happening. A dense network of GPS sensors is being monitored to detect signs of damage in large structures like dams, freeways, and buildings. And thousands of structures are sending strong-motion records to the earthquake engineering community for their use in improving the building codes.

State of the Art

The early-warning system, as originally envisioned, did not happen before TriNet's funding ran out in 2002. But the government folded TriNet into a much larger program, the Advanced National Seismic System, based on the benefits it's already demonstrated. One of the four basic goals of the ANSS is this: "Where feasible, for sites at distance from the epicenter, broadcast an early warning seconds before strong shaking arrives."

The cutting edge of the ANSS program is a near-real-time earthquake display program serving emergency responders and other officials in California. The general public can get earthquake notification service by e-mail that is pretty sophisticated. See what else is offered at the ANSS products and services page.

The experimental ElarmS program is learning to automatically detect and size earthquakes using just the first seconds of shaking, then alert areas farther away that seismic waves are coming. It's begin evaluated as part of the California Integrated Seismic Network (CISN) project.

Warning systems promise to save people's lives and a great deal of money. If only 1 percent of the costs of a single major earthquake can be saved, a warning system will pay for itself many times over.

PS: The ham seismology community has a place in this picture, too. The Public Seismic Network (PSN) is the longtime home of this ingenious group of amateurs.

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