Comments about technological history, system fractures, and human resilience from James R. Chiles, the author of Inviting Disaster: Lessons from the Edge of Technology (HarperBusiness 2001; paperback 2002) and The God Machine: From Boomerangs to Black Hawks, the Story of the Helicopter (Random House, 2007, paperback 2008)

Wednesday, October 13, 2010

Chile's Other Reason to Celebrate: Earthquake Safety

The miner-rescue count is now 9 and going up by the hour. This piece from the NY Times summarizes why Chile has reason to be proud of persisting with its efforts to locate the miners of San Jose and get them out. And Americans can be proud of assisting with equipment and expertise.

It's easy to forget during the actual rescue, but the first pilot hole to reach Los 33 stands as one of the most remarkable achievements in the entire saga. The men had been out of food for two days when help arrived.

The blitz of media attention is a little embarrassing (I think of the quote about the White House press corps, the "herd shot round the world") but it helps offset the lack of press attention earlier this year to Chile's world-class achievements in earthquake safety. The Maule temblor on February 27, 2010, was extremely powerful (magnitude 8.8) yet caused remarkably little death and destruction. Only one percent of tall buildings were damaged beyond repair. The biggest damage showed up in individual masonry dwellings not built to code, and bridges built before modern seismic code requirements.

While it's unfair to draw direct comparisons to Haiti, because the focus of the Haitian temblor was close to a major population center, I find it striking that while the Chilean temblor released 500 times as much energy as the one in Haiti, fewer than 800 people died in Chile, compared to 220,000 in Haiti.

The reason for Chile's rigorous attention to strong design and good construction materials: that southern nation gets the Big Ones. Chile suffered the most powerful earthquake ever recorded, the 9.5 magnitude monster of 1960 near Valdivia. Located on the Ring of Fire and therefore subject to frequent if smaller reminders, Chileans have never forgotten the danger they face. With each earthquake, Chilean engineers study the damage and tune up their building codes. As an example, Engineering News Record reported that the Chilean quake showed the need for more confinement of the steel reinforcement in tall buildings' concrete load-bearing walls.)

Over time, nature takes the bad buildings away and better ones take their place. Here's a link to a piece I wrote on earthquake engineering for Invention&Technology.

We could learn much from the Chileans, such as: "Don't get fancy with steel moment-resisting frame buildings by designing them to the bare minimum of the earthquake code. Go with what's worked." This should have been obvious after the Northridge earthquake, but we need reminders.

Another lesson for the US comes from the 1995 Great Hanshin Earthquake in Kobe. Quake-prone regions like the Los Angeles basin put themselves at risk by refusing to mandate the installation of seismic shutoffs on all natural-gas service lines. After horrific experiences in Kobe, where people were trapped in burning rubble and firefighters could not reach them, the Japanese passed a simple mandate that requires gas shutoffs in all occupied buildings, old or new.

In Southern California, because of political resistance, many building owners are not required to install seismic gas shutoffs or excess-flow valves. Why does it matter? The LA basin has two million wooden buildings; an earthquake will start fires, break gas lines and knock out water supplies to hydrants. This will leave firefighters to hunt for ponds and swimming pools. If an earthquake strikes that is big and close, and during a workday when residents are gone and therefore unable to shut off their gas immediately, there is risk of a firestorm big enough to jump interstate highways. While the term "firestorm" was often used in the San Bruno gas-explosion news accounts, a real firestorm is something else entirely.

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