Lucy Jones of the USGS discusses areas of California where there have been clusters of earthquakes in four-year periods at Caltech on Thursday. The symposium was held to coincide with the 20th anniversary of the Landers earthquake. (Walt Mancini / Staff Photographer)

A session of the Japanese parliament is being rebroadcast on a screen at the front of a classroom at Caltech.

Without warning, a "ping" sound is heard on audio, and a message bar at the bottom of the screen informs viewers that an earthquake has struck off the coast of Japan. It's the beginning of the devastating March 2011 tsunami disaster on the east coast of Japan.

It will be more than one minute before the members of the Japanese parliament start to feel the shaking and look up at the swaying lights. But in that time, the broadcast has been interrupted with public announcements about the earthquake, residents of affected areas have been warned to take cover, planes, elevators and subways have stopped, lives have been saved.

"Millions of people got warnings before they felt the shaking," said Doug Given, earthquake early warning coordinator for the USGS.

Given was one of the speakers at a U.S. Geological Survey conference Thursday at Caltech to mark the 20th anniversary of the magnitude 7.3 Landers earthquake on June 28, 1992. The Landers quake was linked to three deaths and an estimated $92 million in damage.

The conference at Caltech brought together government officials, emergency workers and the media to learn from USGS scientists what happened at Landers and what would be different today, based on tools the USGS now provides.

Scientists now have an array of sophisticated earthquake products for Southern

California, such as "ShakeMaps," which show the severity of shaking in various geographical regions; earthquake probability models; and PAGER (Prompt Assessment of Global Earthquakes for Response), which gives estimates of potential fatalities, costs and exposed populations in about 20 minutes from the start of a quake.

The information allows first responders to react to the areas where need is greatest. It also prioritizes inspections of bridges and overpasses where they are most needed.

Lucy Jones, a USGS seismologist who got the nickname "Earthquake Mom" after appearing on TV with her sons after an earthquake, said the data in the ShakeMaps used to take months to produce.

"All of the things we can give you now in minutes" took months in Landers, she said.

Jones, who was one of the scientists at the Landers quake, spoke on the USGS Operational Earthquake Forecasting project, an effort to provide communities with information that can be used to make decisions in advance of potentially destructive earthquakes.

While scientists cannot predict earthquakes, they know earthquakes occur in clusters. When an earthquake occurs, the likelihood of another quake increases.

"It's been really quiet for the last 18 years," Jones said during a conference break. "Don't count on it lasting."

But progress to warn residents immediately after an earthquake, such as was done in Japan, has stalled in the United States.

According to Given, California has a test system in place, but it's just a test system "put together with duct tape and baling wire."

Going the next step will take additional government funding, which hasn't been available in recent years, Given said. The system would take two to three years to develop given funding, he said.

What people could do with even a few seconds warning of a pending earthquake is substantial. People can be warned to take cover, automated systems can react or shut down. It's feasible, it works and it's worth it, said Given.

"It can protect lives and property," he said.