Scenes from Peru prove the basic rule of earthquake safety: "earthquakes don't kill people, buildings kill people. Building codes really work," said Dr. William Leith.
Dr. Leith is with the United States Geological Survey.
Proof? The 1989 San Francisco quake in which most of the city stood because of strict building codes enforced, but that was a magnitude 6.9 quake.
Peru's was an 8--shaking buildings there with more than 30 times as much energy.
Could San Francisco have stood that?
"I am sure a magnitude 8 in California would cause less damage than the one in Peru, but... there would be significant damage. What is problematic is the older buildings that were built earlier in the 20th century," said Dr. Leith.
The cost of retrofitting these buildings remains very high," said Leith.
That's why this United State Geological Map is important: it shows where chances of severe shaking from quakes are highest, thus where spending money to meet code is most important not only on the West Coast, but the New Madrid fault.
It's the scene of major earthquakes in the early 1800's and now threatening Memphis , St. Louis and Evansville Illinois.
Many of their larger buildings are not up to earthquake code though the Midwest's many wood-frame houses are.
"Wood frame houses are generally earthquake resistant. They're more flexible," said Leith.
The East Coast, including New York City, has increased risk zones as well - not as likely as the West Coast, but with more death and destruction if a big quake does hit because there are so many more old buildings.