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Indiscriminate Force Rocks Japan

Posted by Wesley Dodson on May 3, 2011
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The staggering 9.0 magnitude earthquake that struck off the coast of Japan March 11 sent a thirty foot tall tsunami raging up to six miles inland, with diminished waves reaching all the way to the Pacific Islands and the shores of North America. In Japan, thousands are dead, and the devastation is stunning. On Thoughts from Kansas, Josh Rosenau reflects that due Japanese diligence may have spared millions of lives, noting “the earthquake in Haiti last year, which was 100 times weaker, killed 230,000.” On Observations of a Nerd, Christie Wilcox recounts her experience in Hawaii, from watching the disaster unfold on television to waiting for the “eerie tsunami sirens” to wail. And Greg Laden screens a collection of videos showing the initial havoc in Japan.

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Comments

  1. #1 Joffan
    May 3, 2011

    Another huge difference is that most of the Japanesse fatalities, as far as I could gather, were due to the tsunami, not the earthquake. So the difference in earthquake fatalities between the two events is even larger – perhaps close to a factor of a thousand.

    It would be more instructive, comparing the two, to look at comparable sized communities which are a comparable distance from the epicentre, or (following Remo) experienced comparable ground accelerations.

    Also, I’d like to quibble with the use of “thirty foot tall” to describe the tsunami. Not the measurement – the adjective. “Thirty foot high” better captures the nature of this implacable deluge.

  2. #2 healthphysicist
    May 3, 2011

    I have had several of my comments never post on Laden’s blog.

    He had to “review” them first.

    Beware.

  3. #3 Remo
    May 3, 2011

    Oops, I forgot to post the shake map for Haiti. Here it is: http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/2010rja6/

  4. #4 Remo
    May 3, 2011

    Echoing and expanding on mpatel’s thoughts, you really can’t compare Haiti and Japan. Look at the USGS shake map for Japan. Although there was a huge area affected, no place would you expect ground acceleration to reach more than 0.5g. Ref: http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/c0001xgp/ (I note that there were several locations in Japan where the actual shaking exceed 1g. Actual shaking is also influenced by soil type, wave type, and local geography. Computer modeling is imperfect)

    However, with Haiti, 300,000 people lived in a region where the expected shaking would exceed 1.0 g and another 2 million lived in a region where they would be predicted to have ground shaking on the order of 0.3 to 1.0 g.

    Yes, the lack of building codes and construction standards was a large contributor to Haiti’s death toll. But there was also a very large population living in an area of violent shaking.

    I live in California. The building standard for new home construction here is to survive (with damage) shaking of 1.0 g. But we have a large stock of older homes that don’t meet this standard. Still, these older homes are better constructed than most of Haiti’s.

    If Haiti had modern construction standards, there would have been significant less loss of life (rough guess a decrease of 10x to 100x), but it still would have been a severe event because of the proximity to the earthquake epicenter.

  5. #5 mpatel77
    May 3, 2011

    Though true that the Japanese reaction to the earthquake was very diligent, I think the increased loss of life in Haiti’s earthquake can be attributed more to the fact that the epicenter of the quake in Haiti was approx. 10 miles from the capital, while Japan’s epicenter was approx. 80 miles from Sendai (closest city to the epicenter). Another reason for Haiti’s larger number of fatalities could be due to the fact that the Japanese infrastructure, policies/procedures and disaster recovery plans are designed to take earthquakes into account.