The radiation chart pasted below was posted by a Japanese blogger. It represents a large spike in radiation, which the blogger attributes to the Sep 14 2014 anomaly at Fukushima. I am unable to verify because I'm having trouble translating the page and decoding the location for the chart.
This is quite a spike.
Please see this pdf I created of images from the event including:
Early morning flashes (TEPCO cam)
Strange gray cloud over Daiichi at dawn (Futaba cam)
Pink mushroom cloud over Daiichi morning (Futaba cam)
My hypothesis is hot fuel rod fragments or melted corium are fissioning on the floor of the port. Perhaps the X1 class solar flare that came impacted Earth that day may have contributed.
I have no way of testing my hypothesis. I've seen what looked like "fire" in this location before. Please see my pdf of "scary" Fukushima screenshots, focusing on the shots from the summer of 2013 https://www.dropbox.com/s/6c1j0jnp061w7uc/Scary%20Fukushima%20W
My other piece of circumstantial evidence is TEPCO's announcement that it plans on cementing the port
Kimura, Shunsuke (2014, Sep 3) TEPCO coating seafloor at Fukushima port with special cement mixture. The Asahi Shimbun,http://ajw.asahi.com/article/0311disaster/fukushima/AJ201409030043
However, it is worth noting that 5 days later the East Coast of the US is showing higher than ordinary rads under the jet stream:
From Netc.com at 10:45 AM US Eastern Standard Time
Today's Jet Stream, seen in an animated format at Weather underground matches up pretty well to the elevated rad readings above (source here).:
Of course, the source for the elevated rads could be closer to home as well.