Update on the Magnitude 7.3 outer-rise earthquake on December 7 off Miyagi Prefecture. (Yesterday's report is here.)
It looks something may have happened at Fukushima II Nuclear Power Plant. According to TEPCO, there was a small rise in pressure in the reactor building, which is to be kept at a negative pressure to prevent radioactive contamination from spreading into the environment.
Jiji Tsushin (12/7/2012):
TEPCO: Fukushima I Nuke Plant "No abnormality", Fukushima II [reactor] building pressure rise
TEPCO announced that there was no new abnormality in Fukushima I and II Nuclear Power Plants. The quake measured on site was small, and it didn't affect the water injection into the reactors or the cooling of the spent fuel pools.
However, in Fukushima II (Daini) Nuke Plant, the pressure inside the Reactor 1 building rose a little. At 5:20PM, workers lowered the pressure by manually operating [the system that] pumps out the air.
TEPCO's manager Masayuki Ono explained "It's not very serious", even though he acknowledged the company did not know the cause of the pressure rise. According to TEPCO, there is no leak of radioactive materials in the environment.
Ah the famous last word, "No leak of radioactive materials in the environment".
There were 11 people injured in the M7.3 earthquake. There was a M6.2 earthquake 13 minutes after the M7.3 earthquake, but the Japanese tweets say there was no media report on that one, other than in the data pages of Japan Meteorological Agency and other meteorological news sites. Many people say they did indeed felt two shakes.
Right now, some people are trying to figure out what the hell is "autaah raizu" earthquake (and remember, "r" and "l" are indistinguishable to the Japanese) - a transliteration of "outer-rise" earthquake".