Tuesday, 20 September 2011

Rikuzen Takata (4) geography and the tsunami

There has been a lot of comment that people built recklessly in places that were known to be tsunami places.  The implication being that had they not been so foolish, they wouldn't have faced such tragedy. While there is a grain of truth in the statement, it shows little understanding of the Sanriku. The coastline is a vast series of inlets and peninsulas, of river valleys and hills. Principle settlements tend to be close to the rivers, in the valleys.  The hills have some housing but tend to be wooded.  Along the coastline there is little flat land.

A seismologist would undoubtedly be able to use logarithms to work out the reach of a tsunami with all kinds  of variables; however on the ground it can be impossible to see much logic in the sweep of the flow. Houses on a small hill on the point of the bay were find where as houses much further back were swept away.  We cleaned up a rice field well over a km from the sea in Otomo,  in front of the Junior High School (which can be seen on the map below),.  From where we were we had little sense of the direction of the sea -and there was dispute among group members over which it was.  Both were right and the water apparently came from both sides of the peninsula.  The first floor of the JHS school was engulfed, the primary school next door which was a couple of metres higher was OK.

The points were much safer than the inlets, even if they were only slightly elevated.  The angle at which the tsunami approaches seems to have a lot to do with the scope of destruction.

Many people died on high ground on ground they thought was safe - where previous tsunami hadn't reached.

A Map of Rikuzen Takata showing schools, and key public buildings
A terrain map -  looking at this you can see that the roads, trainlines, schools, and town centre in the map above
are build on the flat.

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