Lucy Jones is sitting in a tall chair in a conference room near her office in Pasadena, Calif. She is having makeup applied, preparing for a sit-down with a television crew from the National Geographic Channel. Only two days before, Hurricane Katrina had roared through New Orleans and other Gulf Coast areas, stranding and killing thousands. Images of destroyed homes, desperate crowds and--after Hurricane Rita--interminable evacuation traffic make it easy to imagine a catastrophe that could have an even bigger impact on the national psyche: a high-magnitude earthquake under Los Angeles or San Francisco. As a seismologist and scientist-in-charge for southern California for the U.S. Geological Survey (USGS), Jones has been thinking and talking about the possibility for most of her professional life.

Jones takes the TV crew out to the nearby Eagle Rock fault under the La Loma Bridge in west Pasadena. It's not as famous as the San Andreas fault, but it suits the purposes of the program, which is about scientists' reactions to disaster movies. She explains to the camera that the worst-case scenario for Los Angeles is a big quake when the hot Santa Ana winds are blowing. These breezes from the east would spread fires created by breaks in natural gas lines and the arcing of power lines. "That could remove chunks of real estate," she says, then adds that California will not fall into the ocean. ("There's nowhere for it to fall to.")

A recent study by Jones's colleague Ned Field and others estimates that the losses from a major earthquake (about magnitude 7.5, perhaps a little smaller than the "Big One") under the Puente Hills fault in Los Angeles could total $250 billion and leave several thousand people dead, similar to the 1995 magnitude 6.9 Kobe earthquake in Japan. Another study finds that the San Francisco Bay Area has a 25 percent chance of getting hit with a magnitude 7 or greater earthquake in the next 20 years. Indeed, several years ago the Federal Emergency Management Agency (FEMA) had called such an earthquake one of the three most probable catastrophes threatening the U.S.--the other two were a terrorist attack in New York City and a direct hurricane strike on New Orleans.

The media like to tap Jones's expertise not just because she knows how to explain complicated geology but also because she knows how to soothe an anxious audience. "Lucy has the trust of the general public," says Tom Jordan, director of the Southern California Earthquake Center in Los Angeles, "and they look to her for guidance about how citizens should prepare for and respond to earthquakes. She's both a media star and a respected authority." After the September 11 terrorist attacks and anthrax mailings, the Los Angeles Times called for "a Lucy Jones for bioterrorism" for the region, someone who can inspire trust and therefore encourage cooperation during emergencies.

Jones did not plan on becoming a practitioner of geophysical soothing. After completing her Ph.D. in geophysics at the Massachusetts Institute of Technology, she ended up in 1983 working for the USGS in southern California, where she had grown up. She made her scientific mark studying and applying the statistics of earthquakes. She found, for example, that only a small percentage of earthquakes will prove to be foreshocks. With fellow USGS seismologist Paul Reasenberg, she combined empirical data for aftershock sequences and derived rules for aftershock probabilities once a main shock has occurred (every earthquake has about a 5 percent chance of being followed by a larger one). She continues to analyze temblors statistically and frequently collaborates with her husband, Egill Hauksson, a seismologist at the California Institute of Technology.

But it is being a spokesperson after major quake events that has made Lucy Jones a household name in California. She began making media appearances after the 1986 Palm Springs earthquake but probably made the biggest impression on southern Californians by holding her toddler during television interviews after both the magnitude 6.1 Joshua Tree and magnitude 7.3 Landers earthquakes in 1992. A key attribute: "I have the ability to speak in sound bites, to get the succinct statement," she observes.

Over the years, as she has spoken to the press, she has learned that scientific accuracy is not the top priority after a serious quake--rather people want to be reassured. "People are far more afraid of earthquakes in proportion to the risk they actually pose to their lives," she says. Statistics from the National Safety Council show that an American's lifetime odds of dying in an earthquake is about one in 120,000--by comparison, dying in a transportation accident is 1,500 times more likely.

Jones says her ability to relieve anxiety was never intentional but is something she has thought about after the fact. "My theory is that people are afraid of earthquakes because they are out of [their] control. But seismologists give it a name and a number and a fault, and this puts it back in the box of controllable experiences. Even if an individual doesn't understand what happened, somebody does." In her move to a more explicitly comforting role, she thinks being a woman has helped--"I think that part of it is the female image in the situation. You feel better when Mommy tells you it's okay." After a second she adds, "It's the only time that being a woman in science has been a help!"

The reassuring approach that Jones embodies was missing in the recent hurricane relief efforts. "What happened to FEMA wasn't a surprise," she opines. "They have taken that agency and moved it into Homeland Security, told everybody in the agency that what they're working on is terrorism, and people with interest in natural disasters left [their jobs] if they could." She notes that in the current political climate "terrorism matters more than natural disasters." Jones worries that she and her colleagues have lost the attention of emergency managers, even though "a lot of the things you do in response to earthquakes are the same as you do in response to terrorism," such as training first responders and ensuring efficient communications channels.

Jones recently turned 50, and as she has progressed in her career she's become more involved in issues surrounding the earthquake threat in California. She just completed a term as chair of the California Seismic Safety Commission, a political appointment made by Governor Gray Davis. The commission, an independent board, advises state officials on matters affecting earthquake safety. Members review all legislation, such as those for construction codes, and offer their advice.

One issue revolved around a money-saving proposal to exempt community colleges from the Field Act, which requires stronger construction of schools. It costs 3 percent more to build tougher buildings, and one survey after an earthquake found the damage to Field Act buildings was only 0.3 percent of the value of a building versus 18 percent for non-Field Act buildings. Jones and the commission used such statistics to dissuade lawmakers from exempting the colleges, although Jones expects the bill to be resubmitted.

"It's a real eye-opening experience for me, to see how things don't help people until there's legislation about them," remarks Jones, who is also a member of the California Earthquake Prediction Evaluation Council, a body that examines specific predictions of temblors. Come the next midsize quake in California, or even the Big One, bet on Lucy Jones doing her part--not only explaining the science but also soothing the soul.