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    More ways to measure earthquakes

    Someone mentioned the Mercalli scale of earthquake intensity, so I looked it up. The source that gives the most fleshed-out description of each level was at the Hawaiian Volcano Observatory site. The one that’s decribed in a way that sounds as if it might be very close to the original (which I assume was translated directly from Italian in the 1930’s) was at about.com:


    I. Not felt except by a very few under especially favorable circumstances.



    II. Felt only by a few persons at rest, especially on upper floors of buildings. Delicately suspended objects may swing.



    III. Felt quite noticeably indoors, especially on upper floors of buildings, but many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibration like passing truck. Duration estimated.



    IV. During the day felt indoors by many, outdoors by few. At night some awakened. Dishes, windows, and doors disturbed; walls make creaking sound. Sensation like heavy truck striking building. Standing motorcars rock noticeably.



    V. Felt by nearly everyone; many awakened. Some dishes, windows, etc., broken; a few instances of cracked plaster; unstable objects overturned. Disturbance of trees, poles, and other tall objects sometimes noticed. Pendulum clocks may stop.



    VI. Felt by all; many frightened and run outdoors. Some heavy furniture moved; a few instances of fallen plaster or damaged chimneys. Damage slight.



    VII. Everybody runs outdoors. Damage negligible in buildings of good design and construction slight to moderate in well built ordinary structures; considerable in poorly built or badly designed structures. Some chimneys broken. Noticed by persons driving motor cars.



    VIII. Damage slight in specially designed structures; considerable in ordinary substantial buildings, with partial collapse; great in poorly built structures. Panel walls thrown out of frame structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned. Sand and mud ejected in small amounts. Changes in well water. Persons driving motor cars disturbed.



    IX. Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb; great in substantial buildings, with partial collapse. Buildings shifted off foundations. Ground cracked conspicuously. Underground pipes broken.



    X. Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations; ground badly cracked. Rails bent. Landslides considerable from river banks and steep slopes. Shifted sand and mud. Water splashed over banks.



    XI. Few, if any (masonry), structures remain standing. Bridges destroyed. Broad fissures in ground. Underground pipelines completely out of service. Earth slumps and land slips in soft ground. Rails bent greatly.



    XII. Damage total. Waves seen on ground surfaces. Lines of sight and level distorted. Objects thrown upward into the air.





    Level XII sounds like the apocalypse, with the Earth actually convulsing and objects tossed like confetti.



    What I find interesting is the locution, “Everybody runs outdoors.” That’s the first thing you learn not to do when you live in earthquake country. (Yes, as those last two links indicate, Sunday isn’t the first time I’ve thought about this. The NHK special I referred to was very engagingly put together, even if it inevitably started giving off a sort of “which way do you think you‘ll die?” vibe toward the end, after an hour of computer models of pancaking highways and dramatizations of fires. Hasn’t stopped me from going to basement restaurants, or anything, though. Did I say something recently about avoiding parentheticals? Never mind. I’ll work on that next week.)

    5 Responses to “More ways to measure earthquakes”

    1. John says:

      Hah. Visiting NY dork in our office stood next to a picture window on the 27th floor during an earthquake. After the tremors subsided, we explained about windows having the propensity to opo out, and the unpleasant effects of a slight positive pressure inside tall buildings. Dude never went near another window that whole trip.

    2. Sean Kinsell says:

      Did he think it’d be cool to see the other skyscrapers in the neighborhood flapping in the breeze?
      Of course, given how many office desks are wedged among nice, tall bookcases, you have to watch which direction you run away from the window, too.

    3. John says:

      Our office kept file cabinets out of the way – in locked offices at the corners of the building. Our company’s lifeblood is IP. We had a very un-Japanese attitude to filing sensitve documents in plain sight. (And even our senior managers used computers, not typewriters.)
      Some stranger could walk into most Japanese offices and make off with a lot of important data.

    4. Sean Kinsell says:

      Well, things in Japan are still built under the presumption that everything is safe from crime.
      I hope your IP didn’t feel too undervalued, being relegated to corner offices like that, BTW.

    5. John says:

      We have legal restrictions to keep things confidential, especially when dealing with potential licensing partners. I routinely talked about things I could not dicsuss with my colleagues, in order to keep our internal development groups from contamination should the deal not close (often the case). The open Japanese office is a direct violation of just about every prudent procedure here in the States, so I had to book teleconference time in the corner conference rooms, so that there was no one but the IP documents to overhear me.