Triangle of Life--surviving earthquakes

My sister who works as an Investigator for the Federal Public Defenders Office in Seattle and was sent a copy of this article by their Administrative Officer. I though it might be worth a read.

Basically, it states that the old "duck and cover" we were all taught during the cold war could get you killed in an earth quake. That it would be better to lay flat next to objects rather than under them.

If you wish to read it, click here.

Mike

I live in Central Cal, and have lived in quake country for most of my life (50 years). The reality of living with earthquakes is similar to living with hurricanes in Florida. You build strong buildings and take reasonable steps to prevent the major causes of damage. The last quake within 80 miles was 10 minutes or so ago. /ubbthreads/images/graemlins/smile.gif It was only a 3. It takes a 6 or better to do some real damage.

The building codes in California are such that most earthquakes don't hurt people very often in modern buildings. I've been as high as 7 floors in a major quake and, although the building had some damage, no-one was injured. Most injuries occur in older buildings that have not been retrofitted to code, or where the contractor skimped and cut corners.

We do little things that are not considered necessary in other parts of the country. They minimize the damage and the injuries;

Strap tall object to the walls with simple metal or nylon straps to keep them from falling on people.

Bolt foundations to the sill plates (I think that's right) to keep houses and foundations in the same place.

Bolt large, heavy equipment to the floor and, in some cases the ceiling too.

Gas mains have an automatic shut-off that can be tripped by major earthquakes.



The biggest problem I've encountered after a quake was loss of electricity for a few hours.

There will always be things like the miles of the Cyprus Superstructure that collapsed in the Loma Prieta quake, or the single spot on the bridge that broke. We analyze the failures and correct them. We reinforced every freeway overpass in California after the Loma Prieta quake.

The duck and cover is good advice if you have something sturdy to hide under like an old Steelcase desk.. If it's a K-mart special computer desk, you are better off next to it. Simple logic applied BEFORE a quake makes all the difference.

I'd worry more about hurricanes than quakes. Lots of people die in every one.


Daniel


P.S. There wan't much reason for this post, was there?

[ QUOTE ]
gadget_lover said:

P.S. There wan't much reason for this post, was there?

[/ QUOTE ]

The reason I posted this was simply to give people something to consider is all, just an fyi. It really has nothing to do with hurricanes as neither do the other posts in the Cafe, does it matter? This is the Cafe, I thought something like this could be posted here, I apologize if I was wrong. I can delete it if by your standards you feel it doesn't have any merit or is inconsequential.

Let me know.

Mike

Mike, working in downtown Seattle, earthquakes are something I take fairly seriously. I think a discussion of the problems and postulated solutions are very useful.

I'll try to post more on this when I get some more time.

FWIW, this has been covered a bit on the forums at www.equipped.org.

-john

[ QUOTE ]
_Mike_ said:
[ QUOTE ]
gadget_lover said:

P.S. There wan't much reason for this post, was there?

[/ QUOTE ]

The reason I posted this was simply to give people something to consider is all, just an fyi. It really has nothing to do with hurricanes as neither do the other posts in the Cafe, does it matter? This is the Cafe, I thought something like this could be posted here, I apologize if I was wrong. I can delete it if by your standards you feel it doesn't have any merit or is inconsequential.

Let me know.

Mike

[/ QUOTE ]

I think Gadget_Lover was refering to his own post. /ubbthreads/images/graemlins/ohgeez.gif /ubbthreads/images/graemlins/grin.gif

Possibly, only he can tell us. If that's what he meant, that's cool. Sorry I got un-ruly. /ubbthreads/images/graemlins/wink.gif

Mike

Maybe he feared that you were being prophetic or something. Was there a reason for your post? /ubbthreads/images/graemlins/grin.gif

DOH!!! /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/rant.gif /ubbthreads/images/graemlins/grin.gif

Sorry about that. I read my own post just before submitting it and realized I was just rambling. Probably prompted by the earthquake minutes before I read Mike's post. I was talking about mine, not Mike's.

It's always good to share information, Mike.


To throw out my own opinion....

Earthquakes are not a big deal. They are easy to prepare for and damage/injury is usually confined to the epicenter and buildings that have never been brought up to code. Places I frequent are all built to code.

Tornadoes and Hurricanes, on the other hand, can be so bad that well constructed buildings (cat 5 hurricane) are damaged and they impact a very large area. I'll take quakes any day.

Daniel

Daniel,

Thanks for clearing that up. I've seen enough of your posts to know better than that and then to shoot my mouth off. I am a real dummy!

Please accept my apologies.

Mike

[ QUOTE ]
gadget_lover said:
To throw out my own opinion....

Earthquakes are not a big deal. They are easy to prepare for and damage/injury is usually confined to the epicenter and buildings that have never been brought up to code. Places I frequent are all built to code.


[/ QUOTE ]

Well, life looks pretty different sitting here in downtown Seattle. If I was in a residential area, I might feel differently. I think most of the buildings downtown are up to code, but even so, I think most of the older buildings (like the one I am in) would not fare well at all in a major earthquake. I suspect the newer ones would be fine. The main issue is a lot of them are brick or unreinforced (or under-reinforced) cement. While a lot of retrofitting has been going on, all I have to do is think about what brick is going to do under stress. Then, if you get outside, there is all the stuff falling off buildings. Then, consider Seattle is built on landfill. It seems liquifaction is a potential. Not to mention, my building is right next to the viaduct, which keeps threating to fall over as it is. Not safe inside, not safe outside. We'll just asume we won't have tsunami issues.

Of course, things could be just fine, but I do think there is a fair risk where I'm at.

-john

I'm in a downtown Seattle building that was completed in 1983, so it should be at least reasonably up to code.

From one of my websites, comes the following text:

------------------------------------------------------------------------------------------------------------------------
At 10:54am Feb 28 2001, a magnitude 7.0 (later downgraded to 6.8) earthquake shook downtown Seattle. Although the structural integrity of my building does not appear to have been compromised, the interior of my home sustained virtual total damage.


IMMEDIATE EFFECTS: The quake started as a single "thump", which I mistook for the roofers dropping a piece of machinery on the roof. Several seconds later, a north-to-south swaying motion became evident, which increased in intensity over the next 15-20 seconds. By this time, it was no longer possible for anybody in the building to stand unaided. The dominant sounds were those of breaking glass and large bangs & thumps from furniture, large appliances, and home electronics falling to the floor; and of doors banging back and forth. A loud slow rattling noise was also evident, along with various creaks, cracks, and groans from the building's structure itself. The sound of the elevator car slamming into the walls of the elevator shaft was also evident.

At around 30 seconds, the breaking glass and falling object noises became spaced farther apart as fewer and fewer objects remained upright. The water was thrown out of toilets and fishtanks (those which didn't come down), and hanging fixtures banged against walls or broke off the ceiling.
Finally, at approximately 40 seconds, the violent swaying subsided, and was pretty much gone around ten seconds after that.

A buzzing noise became evident after everything stopped moving. Three sources were located: a computer monitor soaked in water from the fishtank, an outlet strip shorting out from water entry, and the fishtank pump running dry after too much water was thrown out of the tank.
No other damage to live electrical systems was found.

Down the 3rd floor hall, I heard a toliet flush, and then the sound of splashing water and that of something being knocked over and breaking. Presumably, the toilet flooded and its owner was pawing through debris to find their plunger or some towels.

Structural damage to the building was limited to a fractured facade on the north wall (broken off at the roofline, but remained attached by its embedded rebar), numerous cracks on interior joints, several fractured & buckled cinderblock flooring plates on the surface of our outdoor rooftop courtyard, and several ceiling tiles in the lobby ruined by water running down from another busted can on the 4th floor.
------------------------------------------------------------------------------------------------------------------------

<humor>

Now ya see, that's what I mean. Ya live in earthquake country and you don't do things like putting water sources over computers.


Seriously, people who live in places that seldom have earthquakes tend to be hurt more. They aren't prepared like we are in central California.

A few simple tips;

Tall furniture does not fall over if strapped to a stud. Nylon staps or plumber straps.

Appliances don't "walk across the floor" if you use hold down straps in addition to their leveling legs.

Cabinet doors should latch closed. This keeps dishes safer.

Large items like pictures and mirrors should not be over a bed. They tend to fall in a real good quake.

Don't take a job or apartment in a building that is unreinforced masonry.

Don't try to stand or run during a big quake. Get under or next to a sturdy desk before the gyrations get bad. (You did strap that desk to the floor, didn't you?)

There's lots of others.

Sorry to hear that the 2001 quake got you so bad Craig. I hope your fish made it OK.

Daniel

[ QUOTE ]
gadget_lover said:
Don't take a job or apartment in a building that is unreinforced masonry.


[/ QUOTE ]

Jee, thanks for the tip! ::sarcasm/irony:: I'll have to work on that.

Seriously,

1) I'm not sure how many of us would pass on a good job because the building isn't earthquake friendly.

2) It isn't really clear a lot of times exactly how well a given building will fare. For example, a cement building with rebar should probably be fine. One without, not so fine. So how do you know a building has rebar, or how much?

-john

I really hate quakes. I don't have to put up with them here but when I did live where they happened I really hated the ones that came at night when I was asleep. I'd hear all ot the things in my room clinking and wobbling around and by the time I'd finally wake up enough to realize what was happening -- it would be over.

I don't know if anyone else feels that way, but I think that's one of the most disturbing ways to come out of a sound sleep that there is.

[ QUOTE ]
gadget_lover said:
Sorry about that. I read my own post just before submitting it and realized I was just rambling. Probably prompted by the earthquake minutes before I read Mike's post. I was talking about mine, not Mike's.

It's always good to share information, Mike.


To throw out my own opinion....

Earthquakes are not a big deal. They are easy to prepare for and damage/injury is usually confined to the epicenter and buildings that have never been brought up to code. Places I frequent are all built to code.

Tornadoes and Hurricanes, on the other hand, can be so bad that well constructed buildings (cat 5 hurricane) are damaged and they impact a very large area. I'll take quakes any day.

[/ QUOTE ]

It depends on the magnitude. There are very few buildings that can survive a 9.0 (the super quakes caused by thrust fault systems can provide 9.0 plus quakes that last for several minutes). Perhaps a building on a shock isolator (is that the right term?) like some city halls are can survive a quake this size, but the average building in a standard foundation probably won't. The last recorded 9+ quakes took place in the 1960s (Alaska and Chile, IIRC). IIRC, the Alaskan 9.2 lasted 4 minutes (an eternalty in quake time). I don't recall how long the 9.5 Chile quake lasted. Also, my understanding is that the coast of Oregon, Washington, Canada, and the very north of California has a "Mega Thrust" fault system that produces 9.0 sized quakes on average about once every 300 years (according to people that dig up the Earth and look for evidence of past quakes). The historic geological evidence suggests the quakes do NOT happen in even intervals, but instead AVERAGE one every 300 years (some occurances much shorter time, some much longer). The last such quake was believed to have occured around 1700, based on geographical evidence (digging).

My understanding is that even well built buildings are in trouble once you get into the severe quake range (8.0 and above).

The majority of private housing (even those with modern construction) can potentially have failure with quakes in the 7+ range, depending on the condition of the ground (filled ground is worst), length of the quake, depth of the quake, and other factors.

The Bay Area's faults are typically IIRC slip-strike (sideways faults) and do not have as much stored energy as the dip-slip and mega-thrusting faults. Still, a quake in the 7.0-8.0 range is possible, and would devastate many parts of the area (especially places constructed on filled land, and buildings built before the stricter codes). Even well built private homes could potentiall have problems though, its no gaurantee.

Me? I'll take the hurricanes. I'd rather have warning to get out of dodge. A killer quake can come any instant, and once it starts you have to ride it out and hope for the best. With a hurricane, while they happen more frequent, you have time to leave. I feel safer knowing in advance when the poop hits the fan.

This site gives a brief overview of subduction quakes (megathrust):

http://www.pgc.nrcan.gc.ca/seismo/hist/anniv.qa.htm

Other sites go into more detail about the 9.5 in Chile and the 9.2 in Alaska. The only reason the death toll was low in Alaska, IMO, was the sparse population in 1964.

While a 9.0 is nothing to sneer at, an awful lot depends on how close you are to it's epicenter. The futher you are the less damage it does. In general, a quake less than 5 does not do any damage.

We had some quakes just under a 4 that were only 2 miles away. That fault was not on the maps. The jolts were quite noticable. We seldom notice more distant quakes. A 6 something 60 miles away is not noticed at all.

There are maps that show how much damage to expect street by street in the event of a quake on any particular fault. I seem to recall that it would take an 7.5 on the nearest recorded fault to do damage at my house. I use these maps when evaluating sites for new data centers.

I was 40 mile from the epicenter of the 7.1 Loma Prieta in 1989. It felt like the house was swaying, but there was no damage.

I tried to find the list of magnitudes and damage zones, but did not find it. Each magnitude has a defined area of damage. A 5.5 is expected to cause minor damage within 1 mile of it's epicenter, or something like that.

Yes, I dread the day that a 9.5 quake hits a populated area. That's more than 1000 times more movement than the 6.3 that was my worst so far. I was less than 10 miles from that one. It looks like an 8.25 is the highest recorded in California since the middle 1800s.

The reason I prefer quakes is that you don't know where the hurricane is going to go, so you can run, but you don't know if you are safe.

Daniel

[ QUOTE ]
John N said:
[ QUOTE ]
gadget_lover said:
Don't take a job or apartment in a building that is unreinforced masonry.


[/ QUOTE ]

Jee, thanks for the tip! ::sarcasm/irony:: I'll have to work on that.

Seriously,

1) I'm not sure how many of us would pass on a good job because the building isn't earthquake friendly.

-john

[/ QUOTE ]

"earthquake friendly". I like that. It sounds so much better than "Earthquake Safe".

You are right about that. It reminds me of a recent "terror alert" concerning the Golden Gate bridge at commute hour. A woman was hysterical because she had to cross the bridge to get to work and felt she had no choice but to cross the bridge despite the possibility of bombs and such.

I had to conclude that either her job was more important than her life, or that she did not really believe the warning. Her hysteria told me she belived. I could not figure out why she was crossing the bridge.

If you would pass on a jood job because there's a poison manufacturing plant next door, why not look elsewhere if you live near a fault and the building is unsafe?

Daniel

Daniel,

Make sure you look at point#2 of that post. Even if you would pass if the building wasn't up to snuff, how would you really know (I know, in some cases it might be obvious, but in many, I'm not so sure).

So while I'm on a job interview, should I ask them to cover all the earthquake protection features of their building? I would kind of assume this is a good way to get yourself unhired before you even start (because you are obviously a nut, or...).

-john

I guess I've lived in the SF Bay area too long. You can look at a brick building and see the attachement points for the retrofit. You can look inside for the steel cross members that are almost impossible to completely hide. Large diagonal beams are a good clue that it was upgraded.

I don't see why you can't sit in an interview and when asked "Any other questions?", respond with something like "It's beautiful building. Did you have to do much to it after the quake last year?"

Concrete buildings are harder to assess. I've seen buildings designed to carry a lot of weight at the phone company. I've also seen contractors bring in diamond tipped, water cooled hole saws so they could penetrate the rebar when installing equipment. Imagine our dismay when we learned that the contractor had cut through the rebar every 18 inches in a 100 by 30 foot section. The engineer decided he had compromised less than 25% of the rebar and that it was still safe enough to use. So yes, you will have to ask questions about concrete structures.

BTW, I've never turned down an applicant for inquiring intelligently about safety concerns, but I'm not really normal.

Daniel