Given the general fear regarding radiation levels around Japan, this seems the perfect time to give a short introduction to this important topic. There is a lot of confusion regarding radiation and radiation poisoning and this article will try and break it down. 

Radioactive decay
Japan Earthquake Increases Flood Risk In Fukushima


During the 2011 Tohoku Earthquake in Japan, the ground level sank along the coast near Onahama Port,  Fukushima Prefecture. This has caused recent average tide levels to rise by about 40cm.

A tide level recording from Onahama Port shows the tide level fluctuations at the time of the quake and the subsquent increase in tide levels.


Tide level at Onahama, Fukushima Prefecture.
image source: JMA