A 7.3 earthquake [5] hit near Fukushima. That is large earthquake … bigger than the 1989 San Francisco earthquake [6] (But it is much smaller than last year’s 9.0 Japanese earthquake, which produced almost 1,000 times [7] more energy.)
The location was very close to last year’s earthquake. The epicenter of the 2011 earthquake is shown on the left, and of today’s quake on the right:
[8]
Here are webcam videos showing today’s shaking at Fukushima:
A mini tsunami – only 1 yard high [9] – resulted in Ishinomaki, a city in Miyagi prefecture. The earthquake appears to have caused only very limited [10] injuries and property damage.
There are no reports of damage at the Fukushima Daiichi nuclear complex – the nuclear reactors which melted down last year.
There are reports of rising pressure [11] at the Fukushima Daini complex 7 miles away … which narrowly avoided melting down [12] last year. But so far it looks like the problems are minor and contained.
While we dodged a bullet this time, we’ve repeatedly noted [13] that there is a very real danger that an earthquake could damage the fuel pools at Fukushima. For example, we noted [14] in February:
Scientists say that there is a 70% chance [15] of a magnitude 7.0 earthquake hitting Fukushima this year, and a 98% chance within the next 3 years.
Given that nuclear expert Arnie Gundersen says that an earthquake of 7.0 or larger [15] could cause the entire fuel pool structure collapse, it is urgent that everything humanly possible is done to stabilize the structure housing the fuel pools at reactor number 4.
Tepco is doing some construction at the building … it is a race against time under very difficult circumstances, and hopefully Tepco will win.
As AP points out [16]:
The structural integrity of the damaged Unit 4 reactor building has long been a major concern among experts because a collapse of its spent fuel cooling pool could cause a disaster worse than the three reactor meltdowns.
***
Gundersen (who used to build spent fuel pools) explains that there is no protection surrounding the radioactive fuel in the pools. He warns that – if the fuel pools at reactor 4 collapse due to an earthquake – people should get out of Japan, and residents of the West Coast of America and Canada should shut all of their windows and stay inside for a while.
The fuel pool number 4 is apparently not in great shape [17], and there have already been countless earthquakes near the Fukushima region [18] since the 9.0 earthquake last March.
And Germany’s ZDF tv quotes nuclear engineer Yukitero Naka as saying [19]:
If another earthquake occurs then the building [number 4] could collapse and another chain reaction could very likely occur.
Today’s earthquake may show that the fears that a 7.0 earthquake could damage the fuel pools are overblown. But given that the Japanese government said today [20] that an 8.0 earthquake is possible, and given that another monster earthquake is likely [14] at Fukushima, stabilizing the fuel pools is urgently needed as a national security [21] concern.
And see this [22].