When is the next serious quake likely to happen?
There's no easy answer, unfortunately. One USGS expert, Brian Atwater, puts the risk of an earthquake in Washington at "about one in 10... across the next 50 years." Another study says there is a 99.7% chance of California suffering a quake of 6.7 magnitude over the next 30 years.

How much warning will we get?
If we're lucky, a few seconds. "We don’t have any good way to predict earthquakes," says Jim Dieterich, chair of the USGS National Earthquake Prediction Center. “In terms of short-term warning—from a few days or weeks—with high reliability, we’re just not there at this point." California's 2004 temblor occurred without a single precursive quake. But even seconds can be useful: In Japan, thanks to an innovative early warning system, trains stop as soon as a quake begins.

Are U.S. buildings earthquake-proof?
Not enough of them. Even though California instituted one of the "best building codes and construction practice in the world" after quakes in the 70s and 80s, more than 80% of its buildings were constructed before then. An Oregon study found that more than 1,000 state buildings — including schools and hospitals — would be vulnerable to collapse in a major quake. And the impact of even a "moderate" (i.e 6.5 magnitude) quake in the Central and Eastern US is of "real concern," according to seismologist Mary Lou Zoback. In the unlikely event of one hitting New York City, it could cause "more than $1 trillion" in damages and an untold number of deaths.

Can our infrastructure withstand a quake?
No, and this would be where a large earthquake would have the most effect. The American Society of Civil Engineers said last year that 26% of the nation's bridges are "structurally deficient," which means that many would be destroyed by even a minor quake. "We have plenty of buildings that fall down on their own, even without earthquakes," one engineer told USA Today.

What are doing to make ourselves more prepared?
Oregon and Washington are both spending millions on retrofitting schools, bridges, highways and state buildings to withstand earthquakes. Meanwhile seismologists are working to improve their "earthquake forecasts."

Do the recent earthquakes increase the chances of one in the USA?
Experts say no, though evidence suggests that severe earthquakes may provoke temblors some years later. The Chilean quake last weekend might well have been caused by deep stresses in the earth's crust caused by the 9.5 quake that hit the country in 1960.

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