Earthquake Research in Japan Hideki Shimamura, 2003

Earthquake Research in Japan

Hideki Shimamura
Professor, Graduate School of Sciences, Hokkaido University
24 September, 2003

“….The Great Hanshin-Awaji Earthquake was of the secondary type I referred to earlier, in other words a direct-hit-type tremor. As you will recall, this type of earthquake is caused by the bending and distortion that the Japanese archipelago is constantly undergoing, so there is a possibility that they can occur anywhere throughout the archipelago. Compared with the ocean-trench-type quakes that are limited to the areas off the Pacific and Japan Sea coasts, the direct-hit-type earthquakes can be particularly devastating and are especially fearsome since these secondary-type earthquakes can take place anywhere. In terms of frequency of repetition in the same place, however, whereas ocean-trench-type earthquakes tend to recur once every 80-150 years, the interval between these direct-hit secondary earthquakes taking place in the same area is said to be extremely long, at least about 1,000 years”

“….Another concern is what would happen to nuclear power plants in the event of an earthquake. For example, the Hamaoka Nuclear Power Plant is located within what would likely be the epicenter zone in the case of the so-called “Tokai earthquake,” which it is feared could arrive at any time. This facility is designed to withstand an acceleration rate of 450 gals. Actually, Hamaoka has four nuclear reactors, with reactors number one and two being able to withstand up to 450 gals. Reactors number three and four, built later, are a bit stronger, but even so only a portion of their equipment can withstand up to 600 gals. Thus, the emergency core cooling system, a critical mechanism, is still only designed to withstand 450 gals.

Be that as it may, higher acceleration rates than these have been recorded during recent earthquakes. For example, during the Western Tottori Earthquake of 2000, at a location eight kilometers from the epicenter, and moreover on bedrock, acceleration of 575 gals was recorded. We realized that for the first time thanks to the seismographs that have recently been positioned on bedrock beneath the surface in various places. Generally speaking, during an earthquake the swaying is most pronounced on the surface, and that was true in this case as well. But in any event, 575 gals is clearly a much greater value than the assumed level of 450 gals. Therefore, many seismologists are beginning to believe that such data may indicate that we have a significant problem on our hands.”

“Another problem is the assumed earthquake magnitudes relied upon in the construction of nuclear power plants. Their designs assume maximum exposure to direct-hit-type quakes of M6.5. …”

Q: You spoke of the situation at the Hamaoka Nuclear Power Plant. In that regard I read in the press statements made by academic experts Dr. Kiyoo Mogi, [former chairman of the Earthquake Assessment Committee for Areas under Intensified Measures against Earthquake Disasters], and Dr. Katsuhiko Ishibashi [of Kobe University] at an international conference held in Sapporo this summer [the general assembly of the International Union of Geodesy and Geophysics] to the effect that nowhere else in the world has a nuclear power plant like the one at Hamaoka been built at a location where a major earthquake is forecast, based on such a low earthquake magnitude assumption. Is it true that the situation at Hamaoka is really unique in the world? And in reference to these “assumed” magnitude levels, are these figures that the electric power companies just come up with on their own when they want to construct new nuclear power plants?
A: Let me begin by addressing your last question. These design guidelines are established by the national government, not the individual electric power firms, and they determine how things proceed. The criteria for designing the construction of nuclear power plants [Examination Guide for Seismic Design of Nuclear Power Reactor Facilities] were established in 1978 and, after being partially revised in 1981, have remained unchanged since. In addition, in 1995 after the Great Hanshin-Awaji Earthquake, the then Ministry of International Trade and Industry issued a report entitled “Earthquake-Resistance Safety for Nuclear Power Plants” that affirms that adequate countermeasures for earthquakes are ensured for nuclear power plants from the time of construction through operation. In other words, since the design guidelines have not fundamentally changed at all since 1978, there is criticism to the effect that they do not incorporate the advances made in seismology since then.
In reference to conditions outside Japan, there are other nations that are, like Japan, frequently hit by earthquakes. For example, Taiwan is another country that is earthquake-prone. So in that sense, we can say that the building of nuclear power plants in certain other countries is also risky.
Another thing to remember is that although the European continent is a very stable continental mass subject to few earthquakes, about once every millennium it is directly hit in very mysterious fashion by an exceptional kind of inland direct-hit-type quake. For example, in the fourteenth century [1356] the city of Basel in Switzerland was leveled by an earthquake. For that reason, we have no scientific proof to conclude that such a devastating earthquake will not again hit, say, France or Germany. We do not know why the Basel earthquake occurred where it did at that time, but we can venture to say that there is certainly a possibility that this kind of quake will occur again somewhere on the European continent. end quote

Emergency Core Cooling System

The assumption that ECCS work at all was an act of faith in 1967 by the AEC, GE and the United States Government. The assumption that ECCS would in fact work in case of earthquake of any size was also an act of faith.

Semi scale tests took place only after the First Fukushima Diiachi nuclear reactor had already gone on line.

The disaster was not merely the result of uniquely Japanese characteristics, as the Diet dubiously found. It was the result of excellent salesmanship by the United States nuclear authorities and government, who obviously had no clue and who, knowing this (for they had previously acknowledged they didnt know by their commissioning of the Ergen Report) abided no opposition to the siting of the US reactors in Japan. At Fukushima and elsewhere.

Everything said by nuclear industry is a self serving attempt at defense in this matter. In ECCS do not work in Japan, the validity of decisions to deploy reactors anywhere on the assumption that ECCS will work are called into question.

The failure of the back up pumps at Fukushima Diiachi are cited as the cause for the disaster.

In fact the ECCS in all reactors affected at Fukushima Diiachi in March 2011 were all fitted with ECCS which did not require any external power to function. The ECCS at Fukushima Diiachi failed to prevent core overheat, containment failure and meltdown. This is contrary to the public sales pitch given to the public by nuclear authorities from 1967 on. What the hell they told TEPCO is anyone’s guess.

3 Responses to “Earthquake Research in Japan Hideki Shimamura, 2003”

  1. CaptD Says:

    Many believe that the Quake was the REAL CAUSE of Fukushima’s triple meltdowns, yet the MSM continues to cover over that fact using the Tsunami to protect the Nuclear Industry, because Fukushima PROVED that Nature can destroy any land based nuclear reactor, any place anytime 24/7/365!

    The quake has caused serious damage to all of Japans reactors, that is why they remain off line despite what their Gov’t says…

    The SORE (San Onofre Reactor Emergency) is a perfect example of a US reactor design failure that is now just being discussed in the MSM. (see the great technical comments by ex Nuclear worker)

  2. CaptD Says:

    We are lucky that the new Chairwomen of the US NRC is a highly respected Geologist because the NRC needs to start giving much more importance to potential Earth Quakes than they have in the past, illustrated by the fact that US reactors are not build to anywhere near the degree of Earth Movement standards as the ones in Japan and we all know how Fukushima faired when struck by a BIG Earth Quake…

    BTW Many in Japan and elsewhere believe that the Quake not the Tsunami was the true cause of the Fukushima triple meltdown; which if true would be yet another reason to NEVER allow SORE (San Onofre Reactor Emergency) to ever be restarted!

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