16 years ago...

Discussion in 'Off-Topic Discussions' started by Mr. Engineer, Oct 18, 2005.

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  1. Mr. Engineer

    Mr. Engineer member

    16 years ago today --

    The Battle of the Bay was on.

    Was a hot "Indian Summer" day

    Proved that most buildings are built well enough to stand a major quake.

    The Loma Prieta earthquake of 1989 proved that our basic infrastructure isn't so bad afterall. When smaller quakes in other areas of the world kill hundreds of thousands, we sustained major damage to only specific areas (where most deaths occurred). In all, less than 100 people were killed (most on the Cyrpress Structure which was down the street from the old 'hood) It could have been much worse.

    Interesting note: Intel didn't lose a single lot of IC's at their Santa Clara plant. Attesting to a well-built building with a solid emergency plan to back it up.
     
  2. JLV

    JLV Active Member

    It was a 7 on a Richter scale and 100 got killed. This one in Pakistan was 7.6, just a little stronger, but killed thousands. :rolleyes:
     
  3. gkillion

    gkillion New Member

    Correct me if I'm wrong, but I've heard the Richter scale is exponential...ie an 8 is ten times stronger than a 7.
     
  4. Mr. Engineer

    Mr. Engineer member

    LP was 7.2. And yes
     
  5. JLV

    JLV Active Member

    Ok, it seems it is logarythmic sclae and not linear as I supposed. But then that means that both earthquakes can´t be compared at all. A 7.4 earquake is 60% stronger than a 7.2%, and in engineering terms it does make a difference.
     
  6. Mr. Engineer

    Mr. Engineer member

    But earthquakes themselves, along with relative building strengths is not linear either. Most of the damage from LP occurred more than 100 miles from the epicenter in Oakland and SF in area where liquifaction occurred (and vibration was even heavier). I am better that even if the quake was 7.6, there would have only been similiar damage to the area. I have a friend from Iraq - he said that nearly all buidlings are built from unreinforced concrete - his house in Mousel was three stories tall and would probably pancake.
     
  7. BillDayson

    BillDayson New Member

    It was 5:04 PM PDT and I was in Redwood City at the time, at my desk putting my stuff away and thinking about getting to a sports bar or someplace to watch the A's play the Giants in the bay bridge world series. When the earthquake started up I kind of thought it was cool, thinking that it would add a nice California touch to the national baseball coverage.

    Then the shaking suddenly went dramatically down in frequency and up in magnitude. (A geologist later told me that it was probably the building's resonant frequency.) Whatever, suddenly tiles were falling out of the ceiling, filing cabinets were toppling over and some of my coworkers were yelling. I remember suddenly being scared and thinking that 'this ain't no game'. I stood in a doorway (in retrospect I probably should have been under my massive steel government-issue desk.) Then suddenly as it had started, it was over. I tried to call my family but the phones were dead. One of my bosses appeared and hollered for everyone to get out of the building, so everyone got out of the building.

    The streets were filled with people coming out of the surrounding buildings like ants out of a disturbed anthill. Broken glass was all over the place. There were firetrucks slowly prowling the streets, apparently looking for gas leaks. We gathered around a parked car listening to the car's radio, but only one or two radio stations were on the air. They were excitedly saying something about the bay bridge having collapsed, but I couldn't believe that. (It turned out to be an exaggerated rumor of the fact that one small section had partly broken, but I had visions of the whole massive thing splashing into the bay.)

    Eventually I got home where there was no damage to speak of and power was still on, my family all checked in and were fine, and we settled in to watching the disaster coverage on TV stations which were coming back up with emergency generators. It was kind of harrowing, with big swathes of the bay area (including SF itself) without lights, as word of the huge freeway collapse in Oakland spread, as police, fire and hospitals were broadcasting calls for all off-duty personnel to report, and reports surfaced that nobody was having any luck getting through to Santa Cruz which seemed to have fallen off the map. (We feared the worst.)

    (A couple of years later Los Angeles experienced a very similar seismic event in their early-morning Northridge earthquake.)

    But as Mr. Engineer says, it could have been infinitely worse. In Pakistan, it was. He's also right that sound building codes and good construction practices can do wonders in minimizing the effects of moderately large earthquakes. (I guess nothing can minimize the biggest ones like the one that generated the tsunami.)

    But Japan has good building codes and Kobe still ate it after a similar Loma Prieta-sized earthquake. Apparently the problem there was the geology and the location of the earthquake. The Japanese had built a lot of Kobe on landfill next to mountains rising out of the sea. The earthquake waves propagated in towards shore, reflected off the mountain rock and formed interference patterns right under the city. So where the waves added, the soft soil liquified and buildings and structures toppled. But only a short distance away the waves canceled and damage was minimal. Apparently that spottiness was repeated all over the city, with major devastation over here and little damage over there.
     
  8. Mr. Engineer

    Mr. Engineer member

    I was working for a semi company in Fremont right down at the edge of the wetlands. A few pieces of etch equipment was not put on levelling pads. When the earthquake hit, only a few engineers/techs were in the fab. The unlevelled tools rolled forward a bit, pulling the pumps which were in the chase outside of the cleanroom though the wall an into the cleanroom. From then on the rule was to level all equipment and earthquake strap it immediately.

    As far as my house - no damage. My now ex-wife was over 9 months pregnant and was screaming. My son was born a week later...

    Kobe happened because of the arrogance of the Japanese engineers. They thought they were so much better than the average American engineer -- (if you have ever worked in Japan, you would understand this mentality). Alas, Kobe proved that their designs were not as good as they thought and was a definite wakeup call. Do I think we will have a major quake in my lifetime? Of course - I just hope I am not up here on 280 next the the Stanford Linear accelerator when it happens... (or on the Dumbo)

    We never lost power and the telephones worked like they are supposed to (contrary to popular belief, modern phone service doesn't overload if too many people are making a call, it simply limits the amount of calls that can be made. If you pick up your phone and you don't have a dial tone, wait a few minutes - it will turn on once a circuit becomes available. --- additionally, a certain percentage of lines are always left open for emergency services). We did lose cable almost immediately
     
    Last edited by a moderator: Oct 18, 2005
  9. Tom57

    Tom57 Member

    I had just left work and was walking down Montgomery St. in SF with a co-worker. We had just crossed Kearny, and I couldn't figure out why I was stumbling all of a sudden. Then there was glass busting out on the ground floor buildings. I turned around to see a car moving through the intersection, going maybe 2 mph. The driver couldn't control the car, and it veered (careened?)into a light pole. Then my internal alarm went off, and I said "earthquake" to my coworker/friend, who was from NY, and perhaps hadn't felt one like that (neither had I, it turned out).

    We quicky high-tailed it up towards Chinatown where the buildings are much shorter. I had no idea that the earthquake was as severe as it was until after I said goodbye to my co-worker and I made my way to the transbay terminal to catch the bus to Oakland. On the way, I saw huge gaping holes in the street where the pavement had given way. There were reports that the bay bridge had "collapsed." I boarded the bus anyway, since the driver had no idea either. We were turned back before the bridge.

    After much wandering around, I finally made it home by midnight via the ferry. It was only after I got home and flipped on the tv that I saw how severe it was.

    Hard to believe it was 16 years ago.
     
  10. John Bear

    John Bear Senior Member

    Nearly 6,000 days. Where did it go?

    Marina had just left SF airport heading east. The pilot had the interesting decision -- wonder if there is company policy on this -- and chose not to tell the passengers until just before the plane landed in Dallas. I was visiting my publisher in Berkeley, and if I hadn't stayed for the second cup of coffee, I'd have been on the Cypress structure.
     
  11. adireynolds

    adireynolds New Member

    Right, 5:04pm! The first earthquake I ever experienced, and I wasn't even remotely near the epicenter. I was down in Monterey, in the Army, and work had just ended. A colleague of mine and I were on the ground floor of our office building (a converted WWII barracks), when all of a sudden it sounded like about 100 crazed kids running full speed across the room upstairs. We couldn't figure it out, then it hit me -- earthquake! We ran outside, and watched as the asphalt rippled, as waves on the sea would do.

    That's probably one of the scariest things I've ever experienced . .. not being able to trust the solid ground you're walking on to be, well, solid!

    We didn't experience any damage that far south, but I'll certainly never forget the experience.

    I was just in India a couple of weeks ago, and was in Gujarat -- home of the massive quake in 2001. There are still plenty of signs of damage left even from that one. I read that for this latest quake, the Gujaratis were able to offer a lot of practical aid and support, thanks to their recent tragic experience and subsequent improvements in their own building codes, infrastructure, etc.

    Cheers,
    Adrienne
     

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