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Top>Opinion>What the "2011 Tohoku - Pacific Ocean Earthquake" Has Left the Tokyo Metropolitan Area


Hirokazu Hirano

Hirokazu Hirano [Profile]

What the "2011 Tohoku - Pacific Ocean Earthquake" Has Left the Tokyo Metropolitan Area

Hirokazu Hirano
Professor, Faculty of Policy Studies, Chuo University,
Areas of Specialization: Structural engineering, seismic engineering, environmental simulation

1. Introduction

First of all, I would like to send my deepest sympathy to all those suffering from the Tohoku - Pacific Ocean Earthquake.

At 14:46 on March 11th, 2001, a major 9.0-magnitude earthquake, where a fault shifted five hundred kilometers north and south, and two hundred kilometers east and west twenty-four kilometers deep off the Sanriku Coast (roughly a hundred and thirty kilometers east-southeast of the Oshika Peninsula) has struck. This earthquake had about forty times more energy than the 7.9-magnitude Great Kanto Earthquake of 1923 did, it was the strongest earthquake in the history of Japan, and it was the fourth strongest earthquake in the world as of the twentieth century. The March 7th earthquake, which is believed to be a foreshock, and the tsunami warnings are still fresh memories. The extent of the damage becomes clearer by the moment, and here, I would like to relay my experience to the residents of the Tokyo Metropolitan Area.

2. An Unforeseen Major Earthquake

At the beginning of the theses that I wrote four years ago 1),2), I stated that (if there were to be a major unforeseen earthquake) it would occur within the next thirty years, it would be an ocean-trench earthquake like the one off the coast of Miyagi Prefecture-which has a 99% probability rate, the Tokai Earthquake, which can occur at any time, and the Tonankai and Nankai earthquakes (abbreviated), which have 50% probability rates-and that it would powerfully excite ground motion for a somewhat long period of time. In addition to the earthquake off the coast of Miyagi Prefecture with an expected magnitude of 8.0 (1/30th the energy of the March 11th earthquake or less), the Sanriku Coast earthquake and Fukushima/Ibaraki Prefecture Coast earthquakes had started a chain reaction. This is what is believed to have generated such enormous amounts of energy. It was most certainly an unforeseen major earthquake.

Furthermore, it is believed to have been an earthquake that lasted for a somewhat long period of two to twenty seconds because it was an ocean-trench earthquake. The fault slowly moving far distances may have caused the massive tsunamis. Furthermore, although it cannot be said for certain because it is impossible to conduct detailed investigations about land areas at the moment on March 15th, there is the strong possibility of damage including the outer walls and ceilings falling off of structures such as tall buildings, the damaging of large bridges, the overflowing of oil storage tanks, nuclear fuel storage pools, and so on due to sloshing. All we can do is wait for further investigations.

1) A Study on Sloshing Behavior of Floating-Roof-Tank-The Experiment of Vibration with .PHI.4000 Tank Model, Proceedings of the Japan Society of Civil Engineers, A, Vol.63, No.3, pp.444-453, 2007.6.
2) Experiment Method Proposal on Sloshing Behavior of Real Scale Floating-Roof-Tank Using Wave Generator System, Proceedings of the Japan Society of Civil Engineers, A, Vol.65, No.3, pp.568-573, 2009.9.

3. Lessons for Those of Us Living in the Tokyo Metropolitan Area

It is no exaggeration to say that this is the first major earthquake that those of us who live in the Tokyo Metropolitan Area have ever encountered. We have gone through various kinds of training, but have we been able to apply what we have learned?

(1) During the Earthquake

During the earthquake, I was holding a meeting on the eleventh floor of the Japan Coast Guard building (part of the Ministry of Land, Infrastructure, Transport and Tourism). At first, the floor was shaking up and down for a minute. After a little while, the floor started to shake side to side periodically for ten seconds at a time. The time lag between the shakes up and down and the shaking from side to side told me that the epicenter was far, and the period being a little long told me that it was an ocean-trench earthquake. As I immediately turned on my portable radio (which I always carry with me), I heard that there was an earthquake measuring seven on the Japanese intensity scale in Kurihara City, and that there was a warning of a large tsunami. I called off the meeting and started to gather information from the Japan Coast Guard headquarters right away. About fifteen minutes later, I saw footage of the tsunami on the monitor.

(2) Commuter Refugees

By 17:00, we realized that it was impossible to get home and decided to stand by at the University's Korakuen campus. During a disaster, it is important to go home after waiting a while instead of trying to get home right away if there is traffic gridlock.

The front of the Imperial Palace can be seen from the Japan Coast Guard building, and we saw that no cars were moving in either direction on Uchibori Street by the Sakuradamon Gate at the Imperial Palace due to a traffic jam, and that the sidewalks were filled with pedestrians. At 18:00, I left the Japan Coast Guard building and headed toward the Korakuen campus on foot. On the way there, I saw cars stuck in traffic and emergency vehicles having a hard time getting from place to place. The sidewalks were so crowded that everyone seemed to be bumping into each other. It took an hour and a half to get from Sakuradamon Gate to the Korakuen campus after passing through Takebashi and Suidobashi.

At the Korakuen campus, we tried to keep the students from leaving the premises and heading home until modes of transportation became operable again. This was a very good idea because keeping the students apart from such huge crowds was the best way to protect them. We understood how badly they wanted to rush back home, but it was important to consider their safety first and discourage them from leaving. The training at the Korakuen campus for distributing items such as emergency food, emergency water, and thermal sheets had paid off. This was one case where the guardians were able to confirm that their children were safe as long as they were on campus.

I had work to do early in the morning at the Tama campus so I left the Korakuen campus at four in the morning when Shinjuku Station was less crowded, went to Shinjuku-Nishiguchi Station on the Oedo Line, and reached my home in Nagayama on the Keio Line from Shinjuku at five-thirty. Consequently, I got home at the same time I would have if I had waited around impatiently at a major station for the trains to run. The information I had received until that time made me realize just how important the information I gathered from my portable radio was and how important it is to always keep a radio in my bag.

4. What the Residents of the Tokyo Metropolitan Area Must Bear in Mind

It has now been four days since the earthquake struck. At this point, the most important thing to do is rescuing the victims and sending relief to the survivors.

However, the opposite is now happening in the Tokyo Metropolitan Area. A major sign of this is the shortage of supplies due to people hoarding. The supermarkets in Tama New Town are lined up with over two hundred customers at opening time and there are repeated limits on entry. Everything from rice, bread, natto (fermented soybeans), instant noodles, and mineral water to disposable diapers are disappearing from the shelves. Gasoline, kerosene, portable gas stoves, dry-cell batteries, and other resources are also being stockpiled. The items that would normally be sent to afflicted areas first are disappearing because of a number of consumers hoarding them in the Tokyo Metropolitan Area. The immediate hoarding of bare necessities in the Tokyo Metropolitan Area must be avoided because we already have plenty of them. Now is the time for each and every one of us to stay calm and not gather more than what we need. My wish is for each and every one of us living in the Tokyo Metropolitan Area to first place priority on those in the afflicted areas.

5. What the Residents of the Tokyo Metropolitan Area Can Do to Help

There are now rolling blackouts in the Tokyo Metropolitan Area and it is affecting our commuting, but this has not had much of an impact on our usual way of life. There is more that we can do aside from not stocking up on resources. The residents of the Tokyo Metropolitan Area can also conserve more energy. First, we must make sure that we do not use energy excessively. As it is also subject to rolling blackouts, Building No. 11 of the Faculty of Policy Studies, which I belong to, is doing what it can to conserve energy. It may not be much, but in the daytime, we are turning off our fluorescent lights in the hallways that have windows, we use only half the lights in the laboratories, and we are using only one of our three information laboratories. These are things that can also be done in every home. Just a little energy conservation is what any resident in the Tokyo Metropolitan Area can do to help, and this adds up to part of the disaster recovery process.

6. Conclusion

The number of fatalities continues to grow every moment. There are also further reports of damages such as the explosion at the Tokyo Electric Power Company's Fukushima I Nuclear Power Plant. Meanwhile, there is absolutely no information on the damage of land areas other than on what has happened in the coastal areas. We have no idea of how much more damage there is to come. It may take five years, ten years, or even longer until full recovery. It is up to all of us, who live in the Tokyo Metropolitan Area to help, no matter how insignificant our help may be.

March 15th, 2011

Hirokazu Hirano
Professor, Faculty of Policy Studies, Chuo University,
Areas of Specialization: Structural engineering, seismic engineering, environmental simulation
Born in Tokyo in 1955. Graduated from the Department of Civil Engineering (currently the Department of Civil and Environmental Engineering) of the Faculty of Science and Engineering, Chuo University in 1979. Joined Mitsui Engineering & Shipbuilding Co., Ltd. after completing the Master's Program of the Chuo University Graduate School of Science and Engineering with a major in civil engineering. Served as a Part-Time Lecturer at the Chuo University Faculty of Science and Engineering and as an Assistant Professor/Associate Professor at the Faculty of Policy Studies. Assumed the position of Chuo University Professor in 1998. Holds a PhD in engineering.
Conducts both experiments and numerical analyses to perform research regarding the prevention of swaying in structures due to factors such as wind and earthquakes. In addition to authoring research theses, has developed various types of vibration control devices that use simple mechanisms for preventing swaying. Such devices are used at companies such as Metropolitan Expressway Co., Ltd. Received first royalties from his patent at Chuo University.