In one of the worst hot spots, Kashiwa Chiba, they measured 57.5 microSv/h.
It is an empty area surrounded by houses or factories.
10/18/2011, citizens reported they measured 20 micro Sv/h to the city government.
When they dug the ground 20cm deep, it was 57.5 micro Sv/h.
They covered the spot with a seat and put sand on top of it all.
The 3m area is now a forbidden zone.
The city government states it is hard to assume that it has something to do with Fukushima because it’s higher underground.
However, radioactive particles might have sunk or government secretly abandoned radioactive debris to the area with no notice.
Actually the area is owned by the city government. Until 10 years ago, there was a municipal house there.