I attended an earthquake preparedness workshop presented by the U.S. Geological Survey (USGS) the other day where several large agencies and companies presented what they have to done to strengthen their part of the public infrastructure since Loma Prieta hit 25 years ago. Everyone agrees that Loma Prieta was just a wake-up call and this session was asking the question “did we wake up or what?” It was interesting to hear presentations from PG&E, San Francisco Water and Sewer (which runs Hetch Hetchy and supplies drinking water to Los Altos and the surrounding communities), CalTrans and more. After the presentations the speakers participated in a panel discussion to answer questions.
One common theme through all presentations was that in their efforts to strengthen their part of the infrastructure, the focus was on resiliency and not necessarily trying to “earthquake-proof” everything. The consensus was that it was next to impossible to earthquake-proof everything, if not technically, at least financially. Things will break. There will be disruptions” was heard over and over again. So the goal is to build so that it is easy to bring things back into service quickly.
The presentation by CalTrans was particularly interesting. They explained how over the years they learned that simply building bigger and stronger wasn’t the answer. They used the eastern span of the Bay Bridge as an example. Parts of the bridge are designed to fail during an earthquake. But the design is such that these components can be easily and quickly replaced without shutting the bridge down for weeks or even months. Another concern was all the overpasses. They have spent billions strengthening the support columns but CalTrans admits that some roads may be impassible for days after a major eqrthquake. Which brings me to the title of this article.
During the panel discussion the USGS moderator noted that all the major food stores bring in their supplies from the central valley over Interstate 580. If a bridge fails on that route, the food supply into the entire bay area will be severely impacted. How much? The moderator said there was over 300 trucks a day that use the 580 corridor. Think about it – 300 every day seven days a week, and each of those is probably two trailers full of food. That’s a lot of food. And another reason why we need to be prepared to be on our own for at least 72 hours without outside help. And some argue that 72 hours isn’t enough, but that’s for another article.