In the Weintraub column from today’s Bee, he looks at the continued vulnerability, against all prudent thought, still existing in the Bay Area around earthquakes, after having suffered one of the world’s major ones a mere 100 years ago this year.
Some things ring eternal, and counting on luck is so in California
Here is an excerpt.
Daniel Weintraub: 100 years later, Bay Area more vulnerable than ever
By Daniel Weintraub -- Bee Columnist Published 2:15 am PDT Tuesday, April 18, 2006
The last time a big earthquake struck the San Francisco Bay Area, the 1989 Loma Prieta quake, Charles Kircher was trapped in an elevator between floors of an office building in Mountain View.
Kircher, who studies earthquakes for a living, knows that when the next big one hits, he - and the rest of us - will be lucky to get off so easily.
Kircher, a civil engineer based in Palo Alto, is the author of a comprehensive study that looks at the great San Francisco earthquake of 1906 - which struck 100 years ago today - and asks what would happen if a similar quake struck in the same place in 2006.
The short answer is that the disaster could be the human and economic equivalent of a couple of Hurricane Katrinas. The quake could kill thousands, seriously damage tens of thousands of buildings and leave nearly a half-million people homeless. The economic devastation would last for years, if not decades.
"We're talking about a large amount of damage and a large amount of loss," Kircher says.
To estimate the effect of another huge quake, Kircher melded two approaches. One was to go back and look at actual reports of damage in the 1906 quake and estimates of the kind of shaking that must have caused it. The second was to rely on models of shaking that form the heart of our current seismic safety building codes.
He then wedded that information with the latest databases showing where people live, work and travel around Northern California, what kind of buildings we have and how well they are engineered to withstand the kind of shaking that such an earthquake would bring. The result is the most up-to-date scenario of the potential consequences of a repeat of the disaster that destroyed San Francisco 100 years ago.
To put it in context, consider that the 1906 quake came at a time when about 400,000 people lived in San Francisco and only about 1 million people inhabited the entire 19-county region that felt the quake. Today, the city's population has doubled, and 10 million people live in the region. The value of the buildings in the area is estimated at $1 trillion.
Despite vast improvements in technology and stricter building codes, a similar, magnitude 7.9 quake today would be devastating. Among Kircher's conclusions:
* Between 800 and 3,400 people would die in building collapses alone, with the number depending on whether the earthquake hit at night or during the day. Many more could die in fires that start after the shaking stops.
* Between 80,000 and 120,000 residential buildings would suffer serious damage, forcing 250,000 households to evacuate and leaving at least 400,000 people homeless.
* Between 7,000 and 10,000 commercial buildings would suffer major damage, including 40 percent of all commercial buildings in San Francisco and San Mateo counties.
* Most of the Bay Area's highway bridges would suffer damage to their approaches and would likely be closed for at least several days. The Bay Bridge, which was damaged in the 1989 Loma Prieta earthquake and is now being replaced, would be damaged and likely closed for weeks. The tube that carries Bay Area Rapid Transit trains under the bay would suffer extensive damage and probably be closed for at least two years, disrupting service to more than 150,000 passenger trips daily.
