
San Francisco’s Seismic Gamble - montrose
https://www.nytimes.com/interactive/2018/04/17/us/san-francisco-earthquake-seismic-gamble.html
======
mabbo
There are always ways to build the tall buildings safely- they're just more
expensive. These buildings aren't unsafe because there's no choice, they're
unsafe because the builders wanted to save money and the building code was too
loose to stop them.

Japan is a highly volitile region, tectonically speaking, yet they've managed
to build lots of tall buildings safely. How? By having some of the strictest
building codes in the world, yet allowing development within those rules.

Meanwhile, outside of SF itself, the Bay area refuses to build any real
density that's desperately needed, using earthquakes as (one of many) excuses
for NIMBYism and entrenched interests of landlords.

~~~
gibsonf1
As an architect in San Francisco, I would definitely prefer to be in a modern
high rise here over other buildings for safety purposes during an earthquake.
I am highly skeptical of this article as I have in depth knowledge of seismic
engineering, the building code and the updates after every earthquake around
the world to the code and engineering practices.

The leaning building across from my office, for example, has nothing to do
with seismic issues but basic design/engineering/construction flaws in not
extending the pile footings deep enough to solid ground as others in the area
have such as the new Salesforce tower.

~~~
whack
Your comment seems to echo that of another architect quoted in the article.

 _Ron Klemencic, the chief executive of Magnusson Klemencic Associates, the
company that did the structural engineering for Salesforce Tower, says he
agrees that water and sewage systems need higher strength requirements, but
not high rises. “Buildings falling on top of other buildings — that’s not
going to happen,” Mr. Klemencic said._

They never explained why Klemencic's reasoning. Care to explain why _"
buildings falling on top of other buildings — that’s not going to happen"_?

~~~
swampthinker
My understanding is that the way buildings collapse in Hollywood is not how
they collapse in reality. If the base of the structure begins to fail, it
doesn't fall over as a tower, but crumbles into itself.

~~~
komali2
The Twin Towers took out the blocks surrounding them. Literally they fell on
top of other buildings, even though they "collapsed into themselves."

I am very skeptical of anybody, no matter how experienced, that gets on the
news and says "that'll never happen," regardless of what the "that" is.

Has he considered a skilled terrorist cell lacing only the east side of
Salesforce Tower with explosives?

~~~
d0lph
Wouldn't there be bigger concerns, terrorist attacks really don't happen that
often.

It'd be like constantly worrying about protecting yourself from lightning.

~~~
komali2
You're right, but over the course of a building's lifespan, the "chance" is
greater, right? So the chance of a terrorist attack against salesforce tower
this year is less than the chance it might happen sometime in the next 30
years. I'm not good at statistics, though.

Anyway, this is why we have a lot of earthquake preparedness, though the
chance is 5% in the next 30 years.

It's not a "constant worry," so much as a plan. There's non-negligible chance
of terrorist attack, so they architect in such a way to prevent it being
catastrophic. There's a non-negligible chance of your office catching fire, so
they put green exit signs at the door. That sort of thing.

~~~
czep
> though the chance is 5% in the next 30 years.

Not even close. USGS estimates over the next 30 years are: 72% probability of
a M6.7 or higher 51% probability of a M7.0 or higher 20% probability of a M7.5
or higher

Source:
[https://pubs.usgs.gov/fs/2016/3020/fs20163020.pdf](https://pubs.usgs.gov/fs/2016/3020/fs20163020.pdf)

~~~
tenken
And?? California building codes have improved alot since the 1980s or so. I
remember the 1989 LA earthquake as I drove through the aftermath to visit my
grandma about 2 weeks after, I live on the Central coast.

All in all not since 1933 has CA lost more than 100 lives in an earthquake:
[https://en.m.wikipedia.org/wiki/List_of_earthquakes_in_Calif...](https://en.m.wikipedia.org/wiki/List_of_earthquakes_in_California)

That tells me our building codes are pretty damn good.

I work at ucsb and the catilina islands recently had a 5.2 about 2 weeks ago
and the building shook abit. But all in all unless we suffer an 8.0+ I'm not
terribly worried (knock on wood). To put that another way, realistically for
any moderate sized earthquake CA is generally well prepared in terms of
architecture, unless the big one hits ... In which case just kiss your butt
goodbye.

I do wish, even for the big one, that CA invested in an early warning system
like Japan has ... Imagine a 5-50 seconds _warning_ of an earthquake, that
would save lives, not stricter building codes:
[https://youtu.be/OXXZouxPT7U](https://youtu.be/OXXZouxPT7U)

Here is a better, live example of the early warning:
[https://youtu.be/n-FMpNBfna8](https://youtu.be/n-FMpNBfna8)

~~~
ScottBurson
An early warning system might be nice, but stricter building codes are what is
going to save lives. Japan has those too.

It's also worth pointing out that there has arguably not been a large quake
close to a major city center in California since 1906 (for some values of
"large" and "close"). The 1994 Northridge quake, which did some $15B in
damage, was probably the best recent preview we have. Loma Prieta certainly
did serious damage, despite being (as I recall) some 75 miles from San
Francisco.

The real test is when the Calaveras Fault that runs up the east side of the SF
Bay breaks. The last time was 1868, when there wasn't much there; estimated
magnitude was 6.3 to 6.7. A quake of that size on that fault now — and it's
getting to be likely, in the next two or three decades — is going to make a
hell of a mess. We'll find out then how well a lot of things hold up.

------
JackFr
Weird that the word "Japan" occurs 0 times in an article about skyscrapers and
earthquakes.

I realize the focus of the article is SF, but when the author elaborates on
our lack of experience with skyscrapers in earthquakes, with no mention at all
of Japan, it makes me think that this is just a clueless scare piece rather
than any kind of thoughtful analysis.

~~~
vincvinc
Funny, earlier today I just happened to see this Tokyo earthquake footage of
skyscrapers swaying violently:

[https://www.youtube.com/watch?v=ACKMPD6MySs](https://www.youtube.com/watch?v=ACKMPD6MySs)

Then, in the article, I read about San Fransisco:

"the issue of seismic safety of high rises was “never a factor” in the
redevelopment plans"

I can not imagine any positive outcome here.

~~~
sdrothrock
> Funny, earlier today I just happened to see this Tokyo earthquake footage of
> skyscrapers swaying violently

It's unclear from your comment, so I wanted to clarify for other people who
may not know: skyscrapers are intentionally built such that they sway, as that
helps to disperse the energy more than a rigid structure.

[http://www.businessinsider.com/earthquake-resistant-
building...](http://www.businessinsider.com/earthquake-resistant-
buildings-2011-3#the-e-defense-table-is-a-shifting-base-intended-to-simulate-
an-earthquake-7)

[https://earlywarninglabs.com/old/ewl/skyscraper-
safety/](https://earlywarninglabs.com/old/ewl/skyscraper-safety/)

------
komali2
Those of you actually living / working in the Bay Area, I highly recommend
looking into "NERT" \- Neighborhood Emergency Response Team[1].

It's about 18 hours of training on disaster preparedness, earthquake safety,
triage, and search and rescue. The idea is twofold - the more citizens that
can handle themselves and their families for the first 72 hours of a disaster,
the more people that have a 72 hour timeline to death (trapped, injured) the
professionals can find and rescue.

The second is that there is literally no city in the world that has the fire
department resources to handle a catastrophic disaster (>8 earthquake,
tsunami) without "significant loss," and so trained volunteers can do a great
deal to "fill the gap."

In the 1989 earthquake untrained volunteers were critical in helping the SFFD
get water into hoses [2] when the mains went down. Last count I heard is that
there's about 2,000 NERTs now trained in the city. Imagine having 2,000 basic-
trained volunteers helping out in a disaster. Incredible. To put it in
perspective, there's only about 1,500 employees of the SFFD.

There's a city-wide drill this weekend, actually, and they need victim
volunteers. If you want to get painted with gruesome injuries and scream at
people in green hardhats, it could make for a great time! [4]

If you aren't in the bay area, check out the FEMA equivalent, "CERT." [3]

[1] [http://sf-fire.org/neighborhood-emergency-response-team-nert](http://sf-
fire.org/neighborhood-emergency-response-team-nert)

[2]
[http://cdn.abclocal.go.com/content/kgo/images/cms/349779_128...](http://cdn.abclocal.go.com/content/kgo/images/cms/349779_1280x720.jpg)

[3] [https://www.ready.gov/community-emergency-response-
team](https://www.ready.gov/community-emergency-response-team)

[4] [https://www.eventbrite.com/e/victims-needed-volunteer-for-
th...](https://www.eventbrite.com/e/victims-needed-volunteer-for-the-nert-
citywide-drill-tickets-44821250567)

edit- by the way, this training is free, and comes at no obligation to
actually run into burning buildings should a disaster happen (they want you to
take care of your home, family, and neighbors before anything else)

------
cwal37
_" Right now the code says a structure must be engineered to have a 90 percent
chance of avoiding total collapse. But many experts believe that is not
enough.

“Ten percent of buildings will collapse,” said Lucy Jones, the former leader
of natural hazards research at the United States Geological Survey who is
leading a campaign to make building codes in California stronger. “I don’t
understand why that’s acceptable.”"_

One way that reads to me is that an event over some threshold has a high
probability to cause the complete collapse all of those buildings. 90% doesn't
seem like a very high threshold either, if it corresponds straight out to a
1-in-10 event that seems quite bad. If it's a 90% chance of survival in a
1-in-100 event, that's better, but not great.

~~~
cmsmith
Current building codes are intended to design to a 10% probability of collapse
in the "Maximum Considered Earthquake", which is roughly a 2475-year event.
The 2475-year event has a 2% chance of occurring during the (assumed 50 year)
lifetime of a building.

~~~
gruez
>the (assumed 50 year) lifetime of a building

what happens afterwards? is the building supposed to be torn down?

~~~
cmsmith
Nah, the building is (mostly) just as good at the end of that time. It's just
a convenience to make the probabilities easier to conceptualize. If we
designed buildings such that the design earthquake had a 5e-6 daily chance of
occurring, we'd just be confused.

~~~
chris_va
This reminds me of my favorite unit of measurement:
[https://en.wikipedia.org/wiki/Micromort](https://en.wikipedia.org/wiki/Micromort)

If there is a 10% chance of collapse every 2475 years, that is ~1.1/10million
per day chance, or 0.11 micromorts. That assumes 100% death during a collapse,
and that the person spends all day in one of these buildings.

0.11 micromorts/day is very low, which makes the design criteria reasonable.
Of course, I suspect our ability to predict infrequent events with any degree
of accuracy is unlikely.

------
danielvf
This got me wondering what the Salesforce tower’s builders countermeasures
were for the soil and seismic issues. Surely they tried to do something.

Here’s an article about what they did. (Skip the fluff in first third, it does
get down to details later.)

[http://www.structuremag.org/?p=11635](http://www.structuremag.org/?p=11635)

~~~
60654
Because of soil issues, the Transbay Terminal (Salesforce) builders had to
anchor the foundations in the bedrock, which is unfortunately deep under
layers of landfill and soft sand. But this fill and sand is exactly what will
get liquified during a big one, so they didn't have much choice.

But what's weird, IMO, is that some of the shorter highrises like the
Millennium Tower were approved to be built not anchored, but on pylons
floating in the soil layer:

[https://sf.curbed.com/2016/9/16/12945600/why-millennium-
towe...](https://sf.curbed.com/2016/9/16/12945600/why-millennium-tower-
sinking)

[https://sf.curbed.com/2016/9/15/12930402/millennium-
towner-s...](https://sf.curbed.com/2016/9/15/12930402/millennium-towner-
sinking-foundation-buildings)

I mean, sure, as long as things are stable, the weight of the building will
keep it in place. But I don't think anyone knows how the soft layer underneath
most of SOMA will behave, when a big earthquake comes. People know it will
undergo liquification, but by how much, and what will it do to buildings on
"floating" foundations, that's not certain...

~~~
wahern
You assume, based on the journalists' innuendo, that friction piles are per se
not seismically safe. That's wrong. Friction piles are well studied and used
for tall towers in seismic zones all around the world, including Japan.

That the Millennium Tower is sinking asymmetrically doesn't necessarily mean
the design was flawed, even in a high-risk earthquake zone. It could be
flawed, but the very fact that it's sinking doesn't tell us that. It could
merely be that out of the hundreds of towers constructed globally each year,
Millennium Tower was the unlucky outlier which defied the otherwise carefully
weighed odds.

------
czep
"Witnesses on the morning of April 18, 1906, described the city’s streets as
rising and falling like a ribbon carried by the wind."

"one out of every four buildings in the Bay Area might not be usable after a
magnitude 7 earthquake"

"At a time when the average price of a home in San Francisco is above $1.2
million..."

Why aren't people pricing in an earthquake discount? This is so totally
irrational, housing in SF should be cheaper given the certain risk of an
earthquake and consequent large probability of severe damage. And even if your
house isn't destroyed, good luck finding a contractor post-earthquake. Even
now contractors are so hard to find, over priced, and many do shoddy work, I
can't imagine why people don't see this coming and stop paying this much for
something that may fall down any day now.

~~~
kazinator
> _Why aren 't people pricing in an earthquake discount?_

Because it's a matter of insurance, and thus reduced to a recurring premium
bill.

Why not price all maintenance costs and electricity too? Living in this house
for the next fifty years will cost you all these utility bills; you should get
a discount from the purchase price to reflect that! :)

~~~
banachtarski
Lol nobody has earthquake insurance. It's exorbitantly priced.

~~~
jiveturkey
11% of homeowners have earthquake coverage in CA.

[http://www.latimes.com/business/la-fi-agenda-earthquake-
insu...](http://www.latimes.com/business/la-fi-agenda-earthquake-
insurance-20171002-story.html)

Like all insurance, the price reflects the risk vs the number of buyers. If
more people had it, the price would be less exorbitant.

~~~
positr0n
I'd think that 11% of CA homeowners is large enough that you have already hit
the economies of scale and the price is largely a factor of risk. Quintupling
that number is not going to reduce the price.

~~~
kazinator
The number won't quintuple __unless __the price is reduced. Of course if 89%
of the people were cheerfully willing to pay what the 11% are paying, then the
price wouldn 't change. And in that imaginary world, 89% would be covered.

The question is why don't the insurance people work a bit harder to broaden
the coverage; they could make more money even at a lower price point.

Perhaps, those who are not covered are too resistant; they are not willing to
get the coverage even at a reasonable price because of the way they perceive
the risk/benefit. So that is to say, maybe it's a "hard sell".

------
davidhegarty
Love every opportunity to link to this story:
[http://www.slate.com/blogs/the_eye/2014/04/17/the_citicorp_t...](http://www.slate.com/blogs/the_eye/2014/04/17/the_citicorp_tower_design_flaw_that_could_have_wiped_out_the_skyscraper.html)

The Citigroup building in NYC had a fundamental design flaw that could cause
it to collapse.

~~~
bigger_cheese
That story is pretty well known in Engineering circles - we used it as an
ethics case study at my Australian University.

------
songzme
Apparently South Michigan is the safest place to live from natural disasters:
[https://www.quora.com/What-is-the-safest-place-to-live-in-
th...](https://www.quora.com/What-is-the-safest-place-to-live-in-the-USA-that-
is-least-likely-to-be-effected-by-earthquakes-tsunamis-volcanic-eruptions-or-
similar-events#!n=12)

~~~
_jn
IIRC, Las Vegas is also pretty high on that list, hence the data centers.

------
chiph
> The goal of the code, say proponents of a stronger one, should be the
> survival of cities — strengthening water systems, electrical grids and
> cellular networks — not just individual buildings.

I'm not sure how you'd prevent water & sewer lines from breaking during an
earthquake - they're surrounded by earth (or secured along concrete walls in
buried vaults) so they're going to get motion & shear all along their length -
so not much room to flex. Assuming they were made of a flexible material and
not cast iron.

One of the reasons why the 1906 earthquake was so devastating were the fires
afterwards, where the fire companies couldn't get water.

~~~
ceejayoz
After the 1906 earthquake, SF started adding large, distributed cisterns to
store water throughout the city. I'd imagine there are lots of similar sorts
of tweaks you could make - more a focus on a distributed, resilient _grid_
than preventing pipe breaks entirely.

~~~
komali2
Even in 1989 they couldn't get water, they had to suck it out of the bay.

~~~
ceejayoz
That appears to be part of the water supply plan (makes a lot of sense to use
the water they've got there), and the cistern system appears to have partially
functioned:
[http://www.sfmuseum.net/quake/revawss.html](http://www.sfmuseum.net/quake/revawss.html)

> The upper zone of the AWSS, however, functioned normally through the
> earthquake period, and was used to suppress earthquake-caused fires.

Looks like they're building more: [http://abc7news.com/news/over-30-cisterns-
to-be-built-in-sf-...](http://abc7news.com/news/over-30-cisterns-to-be-built-
in-sf-to-prepare-for-earthquake/68515/)

------
0xcafecafe
Of all the natural disasters, I seem to shudder at earthquakes the most. May
be because I am biased by witnessing the destruction brought by the 2001
earthquake in India. The thought that at any moment, without warning, the safe
abode you are in might come crashing down on you is pretty scary.

I wonder with human population increasing and with the shortage of urban land
needing highrises, what is the long term solution to this.

~~~
f_allwein
The long term solution would be having enough energy to modify the earth
enough in order to prevent earthquakes.

From [http://mkaku.org/home/articles/the-physics-of-
extraterrestri...](http://mkaku.org/home/articles/the-physics-of-
extraterrestrial-civilizations/) :

"For example, a Type I civilization is a truly planetary one, which has
mastered most forms of planetary energy. Their energy output may be on the
order of thousands to millions of times our current planetary output. Mark
Twain once said, ”Everyone complains about the weather, but no one does
anything about it.“ This may change with a Type I civilization, which has
enough energy to modify the weather. They also have enough energy to alter the
course of earthquakes, volcanoes, and build cities on their oceans."

~~~
adrianN
It seems a lot easier to build floating cities than to cool Earth's core
enough to stop earthquakes.

~~~
jacquesm
That would be a very stupid thing to do because it would also stop the Earth
magnetic field which helps to shield us from cosmic radiation.

~~~
adrianN
When we have the technology to cool Earths core(!), we'll also be able to make
our own magnetic field.

~~~
kaybe
Stopping plate tectonics also has longterm consequences for the deep carbon
cycle and climate which we'd better be prepared to handle. Though we probably
have to tackle that particular problem way before.

------
Tistel
Great/Scary article. Has anyone worked in the tilting building? Are there
cracks in the walls? Is the soil compaction expected to stop (some max density
type thing)? I think they stopped the tower of Pisa tilting by injecting
concrete under it. It must be difficult to not exasperate they problem at the
start of the injection (I am guessing they have to remove some material
first).

~~~
whafro
I knew someone who lived in the building, and while she didn't report cracks
in the walls, she did say that things would reliably roll toward one corner of
her apartment if they weren't secured.

~~~
tlb
14 inches over 58 stories works out to 0.10 degrees. That doesn't seem like
enough to make anything roll. You might have to shim your billiard table.

~~~
greeneggs
Your math is wrong. The relevant angle is not 14 inches over 58 stories, it is
14 inches over the horizontal length of the building.

I'm not sure what this. Guessing maybe 120 feet, e.g., gives a tilt of 180/pi
* arctan(14/12/120) = 0.56 degrees.

~~~
yaakov34
Sorry, you are the one with the wrong math. The building is out 14 inches at
the top. You divide that by the height to get the angle. What you calculated
is the lean for a building which sank 14 inches on one side. That would be way
worse - an excursion of [edit] 6 feet at the top.

------
product50
Very one sided article and full of scaremongering.

There is no comparison with building codes of other countries which are
earthquake prone (such as JP or TW), only example is provided (Millennium
Tower) and it is unclear if liquifaction will only affect skyscrapers or 1-2
storey buildings too.

------
flyGuyOnTheSly
>Previous earthquakes have revealed flaws with some skyscrapers. A widely used
welding technique was found to rupture during the 1994 Northridge earthquake
in Los Angeles. (Many buildings in San Francisco and Los Angeles have not been
retrofitted.)

That statement really boggles the mind.

How do you own some of the most valuable property in the world, and not
maintain it in the simplest of ways against something that could literally
destroy your investment? After 24 years of knowing that your building was in
danger?

------
jasondc
I thought the massive water tank at the top of One Rincon Hill , to control
swaying in the event of earthquakes, was interesting:
[https://www.sfgate.com/bayarea/article/One-Rincon-tower-
feat...](https://www.sfgate.com/bayarea/article/One-Rincon-tower-features-
water-tank-on-top-to-3299035.php)

~~~
ggcdn
Straight from the article:

> The damper system has no connection with the seismic safety of One Rincon.
> It is always a challenge to build a tall structure in earthquake country,
> and One Rincon's engineering response was to use outriggers, tall reinforced
> concrete columns built around the core of the building.

------
briandear
> For years the city restricted building height to 500 feet in most
> neighborhoods.

Surely that’s a typo? Because that is kind of insane.

~~~
darkerside
Why? That's about a 50 story building.

~~~
Zarel
Yes, which is way higher than I'd expect, given SF's general opposition to
high-rises. According to Google, the actual limit is 40 feet.

Example article I found: [https://recklesslyoptimistic.com/san-franciscos-
height-restr...](https://recklesslyoptimistic.com/san-franciscos-height-
restrictions-and-the-city-s-dark-future-c7796fafb07c)

~~~
darkerside
Here's another article cutting a height restriction near 500 feet.

[http://www.structuremag.org/?p=11635](http://www.structuremag.org/?p=11635)

There are probably more height restrictions in different areas, and a 500 foot
limit is actually quite restrictive. It would have prevented Salesforce Tower.
The Empire State Building is over 100 floors.

------
jumelles
It's not an if, it's a when. You couldn't pay me enough to live in SF.

------
sho
This presentation is absolutely fantastic. Hard to remember a better example
of digital journalism well used. No gimmicks - just relevant information
intuitively presented. Excellent!

~~~
gumby
My mileage aired from yours: I would have been happier simply wth pitctures
rather than something that hijacked the scrolling and interrupted the flow of
reading. Reading on an iPad fwiw.

~~~
sho
I actually went and tried it out on an iPad too. I admit it's not as nice an
experience - in fact it almost seems buggy, scrolling up past the top of the
viewport before the JS notices and suddenly pushes it back down. They could
improve that. At least make it less jarring.

------
nextstep
Reason no. 42614 not to live in the San Francisco Bay Area.

~~~
komali2
Don't live in Houston because hurricanes and flooding.

Don't live in New York or Chicago because cold.

Don't live in Seattle because rain.

Don't live in Taipei because earthquakes and a bunch of cruise missiles
pointed at it.

Don't live in Seoul because artillery and a dictator across the street.

Don't live in Miami because hurricanes.

Don't live in Madison, WI because tornadoes.

Don't live in Hill Country because ambulance will take 20 minutes to get to
you when you step on a rusty barn nail.

~~~
dbasedweeb
Cold and rain seem like they don’t belong on that list unless you’re homeless.

~~~
komali2
There is a reason I moved from cold and rain to an earthquake risk city.

Some people will take death over ever having to shovel again.

------
lmilcin
It seems shockingly irresponsible that it is allowed to build high rises in
areas that can undergo liquefaction.

No matter how strong the building is if the ground gives up it must fall over.

~~~
elgenie
IIRC the proper way to handle that is by anchoring the foundation of the
building to the bedrock underneath the layers which can undergo liquefaction.
That's done by means of drilling as deep as necessary to put the foundation
and then adding pylons on which the building rests.

Depending on how deep the liquefaction-prone layers go, that's could be an
option that's realistic _only_ for a high rise.

~~~
lmilcin
And how does that relate to Millennium tower which has already "sunk a foot
and a half"?

What if high rise building is anchored through all liquefaction-prone layers
but the layers start to shift (they are on slight incline) when they get
liquified? I am not expert but I can imagine it is possible that, if the
structural support is long enough, just few inches of lateral movement may
completely compromise the support.

~~~
stale2002
Because the millennium tower did NOT do the correct thing, and did not anchor
it to bedrock.

They would be having problems if they did it the right way.

------
kozikow
Shameless plug: At my company, tensorflight.com, we use computer vision on
satellite/aerial/street view imagery to extract factors used for predicting
the earthquake damage. For example, construction type or the number of stories
mentioned in the article.

Given factors extracted by us, to get the full picture you may use open source
catastrophe modelling software, Hazus released by FEMA.

