Monday, March 21, 2011

Tales from Japan: Earthquakes Cause Liquification Nightmare in Chiba

Amidst all the news and busyness of recent events, I actually saw Chiba (my local prefecture) shown on the news for the first time last night, after a week of watching the aftermath in Tohoku and the nuclear crisis in Fukushima.

A manhole erupted from the ground during an earthquake in Chiba, photo from Sankei News, JAPAN

Chiba`s biggest problem at the moment is not damage from tsunamis, which pummeled towns in the east after the barrage of earthquakes along the pacific plate, but "land liquification."  A lot of land in Japan, particularly near Tokyo bay and other coastal areas is artificial.  And these areas of artificial land react to large earthquakes by turning to liquid and that as you can see by the pictures below causes a number of structural problems for those cities, as well as poses a very real danger to those living in affected areas.  The ground is literally sinking beneath their own feet, homes, roads, power lines are slowly sinking into the earth with each aftershock or subsequent earthquake.  The once prestine beautiful bay area has turned into a swamp overnight.


Liquified ground that has formed a quicksand type trap

A school in the city of Urayasu flooded from water seeping up through the ground.

A power pole sinks deeper into the weakening land as a result of continued aftershocks

A parked car sinks deeper into the ground in the city of Choshi as result of liquification

A diagram explaining liquification from the Asahi Newspaper
A short translation: Normal land has air bubbles that act as a cushion and protect from rising water pressure.  Liquified land has only sand and not enough air in it to maintain its integrity.

This liquification phenomenon is the great risk of building on artificial land.  Many of course who chose to live in these areas understood the risks, but it is difficult to watch as entire communities sink slowly into what used to be ocean over 30 years ago.  In contrast to these cities along Tokyo Bay, the inland areas of Chiba have sustained little infrastructural damage.  Prominenet cities like Urayasu and Ichikawa that boast high populations are struggling to deal with these problems at the moment.  Most of the extremely liquified areas are nearly inaccessible to the public at the moment, while some areas are now beginnning to allow traffic and people back in.

This certainly brings to mind the parable of the man who built his house on the sand and the other one who built upon the rock. Matthew 7:24-27

Will be posting more information as I am able, the aftershocks have died down quite a bit the last few days, but I just felt one as I typed this sentence.
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