Ask HN: Are thousands of Bay Area workers going to die in a big earthquake? | Hacker News Reader

Ask HN: Are thousands of Bay Area workers going to die in a big earthquake?

54 pointsstaunch17 comments

Looking at liquefaction maps of the Bay Area, it really seems like we're in for a huge disaster at some indefinite point in the future. Many buildings are very old, made of brick, and seem unlikely to survive a big earthquake.

1. Why is it that we have people working in San Francisco in buildings that we know will likely collapse in a large earthquake?

2. How is this legal? How are companies able to ignore the obvious safety implications of having people work inside deathtraps?

3. Will the families of workers get paid when workers are inevitably buried under tons of rubble?

4. Is there something workers can do to force their companies to provide earthquake life insurance and/or move out of unsafe buildings?

https://geomaps.wr.usgs.gov/sfgeo/liquefaction/maps.html

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Two points.

It's not so bad! And it could be really bad!

The not so bad case. The 6.9 Loma Prieta 1989 quake killed 63 people. 42 of those deaths were on the highway collapse. And since then we reinforced the highways and any building touched by construction in the last 30 years was seismically upgraded. Lots of property damage, but we've already paid for that with insurance and taxes. Btw SF's many wood frame buildings that lean against each other do quite well.

  Magnitude      | 30 year chance of one or more
  greater than

  7                51%
  7.5              20%
  8                4%

From:

https://pubs.usgs.gov/fs/2015/3009/pdf/fs2015-3009.pdf

The bad news is the 4% chance event. An 8 or (omg!) 9.0 earthquake. There are few buildings that would survive, some hospitals and data centers that are built to very high standards. (Like the datacenter at 365 Main for example, cool video here [1] about how that works. [2]).

Everything else is likely to be in really bad shape, with thousands of deaths and whole blocks leveled. Current standards don't go that high because it would be much too expensive. Imagine spending $5 million on every house and office building in San Francisco.

The other it-might-be-really-bad direction is that NY Times story below [3] points out that we don't really know how our new skyscrapers will behave even in 7.0 earthquakes, it seems quite possible that a few could fall over and wreck 2-3 blocks of other buildings.

Keep in mind that about 2,500 people die in car accidents every year in California. And that the 4% 8.0+ event only happens every 825 years.

So... not so bad! Could be really bad!

[1] https://www.youtube.com/watch?v=8OVDKZB9r1Q

[2] http://www.datacenterknowledge.com/archives/2009/04/14/quake...

[3] https://www.nytimes.com/interactive/2018/04/17/us/san-franci...

The 1906 quake (the biggest in recorded CA history) was a touch under 8.0, and it killed 3000. But the majority of the damage from it was from fires, which are a much smaller danger nowadays. Building codes are better as well. I'd be surprised if an 8.0 got into the thousands.

A 9.0 quite simply won't happen in CA, because our fault lines aren't capable of generating that magnitude.

If you notice the red brick circles in various intersections around the city. One of the problems with the fires after a quake is that running water may not work anymore, so they installed these cisterns filled with water to try to make sure firefighting water was available if needed.

A minor quibble. No one is predicting one but a 9.0 is not really impossible in the bay area. I think a careful seismologist would say "we aren't predicting one".

The Tohoku earthquake in Japan for example wasn't predicted.

"And yet the disaster of five years ago—a magnitude-9.0 megathrust earthquake off Tohoku, followed by a major tsunami and nuclear accident—came as a surprise. Until March 11, 2011, the consensus among seismologists was that a particular stretch of fault would observe certain rules, rupturing at consistent intervals in events of similar size." [1]

Another Tohoku earthquake quote:

"For decades, seismologists had believed that Japan could not experience an earthquake stronger than magnitude 8.4. In 2005, however, at a conference in Hokudan, a Japanese geologist named Yasutaka Ikeda had argued that the nation should expect a magnitude 9.0 in the near future—with catastrophic consequences, because Japan’s famous earthquake-and-tsunami preparedness, including the height of its sea walls, was based on incorrect science. The presentation was met with polite applause and thereafter largely ignored. Now, Goldfinger realized as the shaking hit the four-minute mark, the planet was proving the Japanese Cassandra right." [2]

This is an active research area and seismologists have a lot of interesting questions to figure out. For example, the Napa fault was discovered... after the Napa earthquake. [3]

And USGS scientists recently found that "the Hayward fault also extends south to connect with the Calaveras fault" and separately "the Hayward fault bends about 10 degrees to the right to connect smoothly with the Rodgers Creek fault underneath San Pablo Bay". [4]

There isn't really anything you can do with this info, a 9.0 is very very unlikely in our lifetimes, but I think it's interesting to know what the state of the art is.

[1] https://www.newyorker.com/magazine/2015/07/20/the-really-big...

[2] https://www.newyorker.com/tech/elements/shaken-beliefs-seism...

[3] http://www.latimes.com/local/california/la-me-quake-napa-fau...

[4] https://www.theverge.com/2016/10/19/13335816/earthquake-faul...

It's possibly more dangerous in terms of odds of dying to earthquake to live in Washington state because the building standards there were not updated to reflect the risk until 1994 or so, and for the roughly 5,000 living/working below the historic tsunami wave line from the last one, there is no escape if they can't get out in fifteen minutes.

https://www.newyorker.com/magazine/2015/07/20/the-really-big...

SF's Millenium Tower, which is tilting, will probably not do well.

> An 8 or (omg!) 9.0 earthquake. There are few buildings that would survive, some hospitals and data centers that are built to very high standards.

San Francisco already had a dozen or so steel skyscrapers by the time of the 1906 earthquake. They all survived the earthquake well, though some succumbed to fire.

  The earthquake damage was inconsiderable. Every
  building on both side of Market Street stood against
  the earthquake. The modern steel-frame buildings
  were unhurt, and that style of structure stands vindicated.
  The city has to rise from the ashes of
  conflagration, and not from the ruins of an earthquake.
  (California State Board of Trade, 1906).

(From https://www.aisc.org/globalassets/aisc/awards/tr-higgins/pas...)

I work in one of those pre-1906 buildings--a 10-story steel skyscraper that was one of the very first on the West coast. Whenever there's a small earthquake the whole building jumps, like a truck hitting a bump in the road. While disconcerting, from everything I've read[2] these buildings are quite safe. They were built to be earthquake resistant (though obviously the science and engineering was nascent back them), but more importantly they were built with riveted steel framing. Riveted connections have proven to be extremely resilient and in combination with other (perhaps accidental) behaviors of the materials and framing techniques they perform remarkably well.

Seismic safety isn't necessarily difficult and certainly isn't anything new. But because labor is expensive (it's why nobody rivets anymore and bolted connections aren't more common) seismic engineering in our era is dominated by high-tech solutions and designs that work with cheaper building methods and cheaper materials. Old tech isn't per se unsafe, and some old tech is better than modern tech, it's just not cost effective.

[2] From literature about the 1906 earthquake and other major earthquakes, various seismic studies (see paper, above), and random stuff like articles discussing the strength of riveted hulls in ship building. Caveat: I'm not an architectural engineer or anything of the sort.

When I started a software dev contract in a Southern California high-rise, I had to undergo 2 hours of earthquake safety training before I could start working.

I think it would be unusual for any Bay Area employer to require any earthquake safety procedures, despite a far higher potential for risk to life and limb.

Very few buildings will collapse in a Bay Area earthquake, but the number is not zero. Far more will be "damaged" and that may still involve plenty of lives lost.

San Francisco I'm not as worried about- the east bay and parts of the peninsula (esp. Foster City) would concern me more.

Best link I've found: http://gis.abag.ca.gov/website/Hazards/?hlyr=liqSusceptibili...

I'm not sure how many brick buildings there actually are. (After the 1906 and 1989 quakes, the flimsiest buildings were knocked down.) San Francisco has fewer brick buildings than most major cities...

And it's also something people (including the government) are aware of and watching carefully. San Francisco retrofits its brick buildings -- over 2,000 by the year 2008 -- and it actually made headlines that there were 150 at that time which hadn't already been retrofitted.

https://www.sfgate.com/news/article/150-S-F-brick-buildings-...

The New York Times recently did an article on the topic: https://www.nytimes.com/interactive/2018/04/17/us/san-franci...

The short answer is that while a natural disaster is possible, the time frame between disastrous earthquakes is long enough for people to get by anyway. Builders do have a legal standard to follow, but whether that standard is safe enough is another question entirely.

Re insurance, many employers offer benefits packages that include basic life insurance coverage for employees, which would likely offer some compensation. YMMV.

Just like in 1906, it won't be the earthquake that kills the most people but the resulting fires.

Think of the forest fires that burnt down Santa Rosa.

In a dense city like SF, it will only take the fire spreading to a few adjacent blocks before it overwhelms the fire departments ability to put it out and that will be it. SF will turn into Coffey park.

Companies don't force people to come and work for them. People make that choice. As of earthquake protection in SF, unfortunately most of the owners don't have earthquake insurances because the premiums are ridiculous. In other words, companies might have earthquake protections in SF if they own their office buildings. Otherwise, not sure it's their responsibilities.

I mean, things aren't really that different from when the Loma Prieta hit. Most of the people who died in that earthquake were on the bridge when it happened. It caused a lot of property damage and injuries but not many fatalities.

That was a magnitude 6.9 earthquake. For context, it has been speculated (source: https://www.newyorker.com/magazine/2015/07/20/the-really-big... ) that the next "really big one" could be in the range of 9.0.

> If the entire zone gives way at once, an event that seismologists call a full-margin rupture, the magnitude will be somewhere between 8.7 and 9.2. That’s the very big one.

I'm not well-versed in earthquakes, but from what I know the Richter magnitude is logarithmic in scale, I can't really even imagine in my head what a 9.0 quake is like.

I'm glad OP / someone is asking these questions, I often wonder about this myself, being a tech worker in San Francisco.

This is for the PNW. The Bay Area is south of that. We won't be hit by one that big. "The big one" here will be an 8, not a 9.

There are geological reasons (stiffness of dirt I think) that a big one near the California coast isn't likely to be that significant. The next earthquake will probably be another Loma Prieta. The ground just isn't very likely to transmit the energy far from the epicenter. Also it's the Hayward fault that's likely to go next.

Yes and thousands of Bay area workers can also die from Alien attack.

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