October 17, 2014 will mark the 25th anniversary of the Loma Prieta earthquake.
In 1988, a group of seismologists came out with a 30% probability of a M6.5 or higher quake in the Loma Prieta zone of the San Andreas fault occurring between 1988 and 2018. It happened a year later. After the dust settled and the fires were out, reporters wanted the answer to one question: was that the big one? The answer was no, not even close.
Aside from yoga and spin studios cropping up on every block, little has changed in the looks of the Marina District since 1989. Many of the replacements for red-tagged buildings of ’89 seem to have been built with a half-hearted attempt to match the 1920s architecture of the neighborhood and tend to stand out with a more modern stucco style.
Most of the 1.6 mile long two-tier Cypress structure collapsed, killing 42 people. Today, a much nicer greenbelt parkway meanders along the footprints of the collapsed freeway.
I would have liked to include the Embarcadero freeway and Candlestick Park with these photos, but I could not get my hands on any 1989 images without copyright restrictions to work with.
I know that the 1989 quake hits much closer to home for many than my previous 1906 earthquake mashups. I create these images not to sensationalize the devastation and suffering, but as a reminder of the past that tends to be quickly forgotten.
At the 1906 earthquake anniversary remembrance last year, I remember supervisor Scott Wiener proudly proclaiming to the crowd with enthusiasm: “We’re ready for the next big one!”
Well actually, we’re nowhere near ready. Many retrofit jobs are complete and new ordinances are speeding up the process, there’s still much work to be done.
If the ’89 quake taught us anything, it’s that San Francisco is woefully under-prepared for the next big one. The Loma Prieta quake was a mini rehearsal of what’s to come. Since the next big one may be similar to 1906, here’s how 1989 compared:
|Duration||Approx 60 seconds||8-15 seconds|
|Magnitude (Richter scale)||7.9 (modified from Richter’s original 8.3)||6.9 (10x less intense and 32x less energy release than 7.9)|
|Modified Mercalli Intensity||X (Intense)||IX (violent)|
|Shake Area||200,000 square miles||25,000 square miles|
|MMI Shakemap(red is bad)|
You can feel the difference between the two for yourself at the California Academy of Sciences’ shake table.
Seismologists predict two possible scenarios for the next big one: it may be very similar to 1906 or it may be a cluster of smaller quakes. The only certainty is that plate boundary stress has accumulated to the point that something big will happen soon.
You would think that San Francisco would have learned from 1906 and made sure that new buildings going up could withstand a similar quake, but in reality the opposite was true. In the rush to rebuild the city, fire codes were reduced and often completely overlooked immediately after 1906. Codes for wind loads and floor loads were reduced by as much as 50%. The priority was to rebuild the city as fast as possible.
The city has grown greatly since 1906. San Francisco’s population has risen from 460k to 837k, and sees over a million people on a typical workday and 14 million tourists a year. Only half of San Francisco’s geography was developed in 1906. Today the city is fully built out. The city has grown geographically too. The Presidio, Yerba Buena, Treasure Island, and SFO have been added. A few high rises in 1906 have grown to over 550 today, some three times taller than 1906’s tallest building.
In 1906, the SFFD had 580 firemen + 100 auxiliaries on duty. Today, SFFD has only 340 fire fighters on duty at a given time.
An insurance report predicted that an earthquake the size of 1906 could see as many as 48,000 buildings destroyed by fire unless the city can dispatch 142 manned engine companies. The city has only 42. To make matters worse, SFFD has a brownout policy that closes four to six companies on any given day for budget purposes.
One thing the city has done mostly right is its auxiliary water supply system. Large hilltop reservoirs are in place to gravity-feed hydrants and 177 cisterns are scattered around the city with 11 million gallons of standby water. However, these resources depend on a well-staffed fire department to deploy in a timely manner.
The city continues to grow, the probability of the big one continues to rise, and SFFD continues to be cut back.
The Loma Prieta quake had everything going for it. Most of the Bay Area was settled in front of their televisions tuned in to the World Series. Many Marina residents were still crowding the Marina Green and Fort Mason parks, enjoying an unusually warm, windless day.
The largest of the 35 fires after the quake broke out in the perfect place and under ideal conditions. The winds were uncharacteristically calm, demonstrated by the perfectly vertical column of smoke from the Marina fire. The large Marina District fire was bordered on three sides by fire breaks: the Marina Green, the bay, and a six-lane roadway. The bay was close enough that fireboat Phoenix could get an endless supply of water to the flames and hundreds of citizens volunteered to pull fire hoses.
Even with all the favorable conditions of October 17, the San Francisco Fire Department was pushed to its absolute limit that day, with 100% of its resources fully-deployed.
The next big one will likely go down something like this:
In the first minute, SFFD will experience a complete resource drain. It will respond to hundreds of immediate rescue needs including hundreds of fire calls and hundreds of building collapse calls.
In the first 15 minutes, at least 50 significant fires will break out that must be stopped immediately.
Every police officer, EMT, MD, and nurse in the city will be called upon to for immediate duty and challenged like never before. Resources in nearby cities will be drained with emergencies of their own and will face transportation infrastructure problems when they try to reach the city. Bridge approaches still cannot be counted on in all places. Ferries and helicopters will be in high demand and operate at capacity. Time and distance will be the immediate enemy.
“I’ll worry about it when it happens” is the prevailing attitude by many who are tired of hearing about the looming big one. And there’s not much more you can do–as long as you’re prepared. But I would bet that most people are not fully prepared or even know what to do the moment it strikes. The media will do its usual blitz of reminders about preparedness for the 25th anniversary of Loma Prieta, but it will all go largely ignored.
I see it every day: restaurants with wine bottles lining shelves above patrons’ heads, bars with towering rows of bottles and glassware up to the ceiling, heavy planters precariously balanced on ledges overhead, frame shop walls covered with glass frames with not even a string to hold them back, gargoyles and other accoutrements hanging on nearly century-old concrete buildings high above the streets. These things will come crashing down by the tons one day. Many businesses everywhere seem to have absolutely no regard for the impending big one. We’re not in Kansas here.
The best you can do now is have your emergencies supplies in order, make sure your home is retrofitted if necessary, and know what to do wherever you are (Hint: getting under a doorway only applies if you are in an old adobe structure and sprinting out of a building onto the sidewalk is probably the worst possible thing you can do.)