On the anniversary of the biggest earthquake to hit Fukuoka in 200 years, we look back and offer tips for preparedness. I’m from Iran and I have experienced several earthquakes, both in Iran and Japan, ranging from minor to big and dangerous. I came to Japan around two and a half years ago. I’m very glad to have the opportunity to study seismology in Japan since it is one of the world’s leading centers of expertise on this subject.
Fukuoka’s Seismicity Revealed
The Kego fault line runs right through the middle of Tenjin in Fukuoka. And yet, in seismological terms, the area has been relatively quiet over the last couple of centuries. This makes it difficult to answer people’s questions about the safety of Fukuoka with regards to earthquakes. But, last year on March 20 the question was kindly answered. ‘Why kindly?’ you may ask. Before answering that, let me briefly explain what happened last year on March 20 in Fukuoka.
A Quiet Sunday…
It was about 10:55 Sunday and I was still in my bed, perhaps the same as many of you. Suddenly, I noticed my TV moving around on its shelf. I thought I was dreaming, but then I realized it was not only my TV; everything was shaking and getting stronger with each moment. As it got stronger, my education kicked in and I realized so far, I had felt P-waves, or primary waves – the first wave types released from a fault during an earthquake. Since they travel faster than other types of waves, they arrive first. So, you feel P-waves, then, depending on your distance from the source of the earthquake you will have a few seconds to prepare for the S-waves which are much stronger and more destructive. I call these seconds between the arrival of P and S waves the ‘last chance.’ And believe me, it really can be the last chance in some cases. Later in this article I’ll let you know what you can do during this time. Many earthquake early warning systems are based on this fact that less destructive P-waves arrive first. Some earthquake-resistant buildings are set up so that as soon as the P-waves are detected, the warning system of the building is activated.
Studying the Quake
The source of last March’s earthquake was estimated to be about 30km off the west Fukuoka coast in the Genkai sea, near Genkai Island. Its magnitude was 7.0 on the Richter scale. The fault that was the source of the quake was found through the study of aftershocks by Kyushu University Seismological and Volcanological Observatory (SEVO). The fault seems to follow the same trend as the Kego fault that passes trough Tenjin but extends into the sea. This is one of the reasons why I said earlier that our question about Fukuoka’s seismicity has been answered kindly. For seismologists, this terrible event contained much useful information. If the quake had happened on the land extension of the Kego fault, the damage could have been many times worse.
The Damage Done
During this earthquake one person died and about 50 were seriously injured. Several hundred people were injured to some degree, and around 300 buildings suffered varying degrees of damage. Genkai Island was particularly badly affected due to its proximity to the source and the older, traditional Japanese houses that are less resistant to shaking than engineer-built ‘mansions’. In Genkai Island about 120 houses were destroyed and 55 others partially damaged. In Fukuoka City too, traditional Japanese houses, particularly in the areas of Daimyo and Imaizumi, were the most heavily damaged; insurance payments for damages were estimated at approximately 15.8 billion. In Tenjin, windows were shattered and concrete cracked. Temples and shrines also suffered damage. Genti Toyokuni, a student of seismology at Kyushu University, surveyed the falling stones and statues of the temples; this can be a serious problem for people visiting shrines or temples to pray for safety during an earthquake. If an earthquake happens and you are in a temple, the area around stone statues should definitely be avoided.
It is important to note in comparison that in the Kobe earthquake in 1995, about 6,500 people died. In some ways, we have been fortunate in Fukuoka that we didn’t suffer so much. Furthermore, that tragic death toll in Kobe occurred in Japan, one of the best prepared countries in the world against earthquake hazards. An earthquake of similar magnitude to last year’s occurred in Iran in 2003 and caused around 30,000 deaths.
After the main shock of the Fukuoka earthquake, several smaller aftershocks happened around the source. An earthquake large enough to cause damage is usually followed by several aftershocks felt within the first hour. The rate of aftershocks decreases quickly; the decrease is proportional to the inverse of time since the main shock. Bigger earthquakes have more numerous and powerful aftershocks. According to my experience, the first week after an earthquake the size of Fukuoka’s is still the ‘red zone’, susceptible to strong aftershocks. However, even after two months some aftershocks could be felt, and exactly one month from the initial quake there was a very strong (6 on the Richter scale) aftershock. Sometimes before big earthquakes, moderate foreshocks happen, but in the case of the Fukuoka earthquake, no clear foreshock was reported. In the case of the Bam earthquake in Iran in 2003, foreshocks were reported the night before the earthquake but due to the lack of high-tech seismic networks, they weren’t officially noticed, unfortunately.
When people hear that I’m studying seismology, the first question they ask is about predicting earthquakes. The prediction of earthquakes has always been one of humanity’s dreams. In fact, predicting the time of an earthquake is just one side of the story and there are institutes and researchers working on this type of prediction. But, most seismologists are working on ‘strong ground motion prediction’. Strong ground motion prediction is based on investigating the existing seismological aspects and the ground condition of each place to determine what would happen during future earthquakes and what amount of shaking could be expected. Some people may think that predicting the time of an earthquake is important, and it is. However, if we know how much shaking to expect and our buildings are prepared for that, then no matter when the earthquake happens, we will be safe.
Perhaps most foreigners have heard about Japan’s seismicity. There is a ‘ring of fire’ that surrounds the Pacific Ocean and includes Japan. Seismologists refer to a Global Seismic Hazard map, showing the parts of the world at the highest risk: east and south Asia, Japan, Indonesia and surrounding areas, south-western China and north India plus Pakistan, Turkey and Iran. Eastern Europe, especially Greece and Italy, has a higher risk, too.
Seeing the damage and casualties caused by earthquakes even in prepared countries such as Japan shows us that we must always be aware of earthquakes wherever we are. Even in advanced, developed countries, we are not perfectly protected against earthquakes, so we should spare a thought for the tragic stories of earthquake disasters in developing countries.
Time: 10:53 March 20, 2005
Magnitude: 7 (Richter scale)
Official Name: Fukuoka Prefecture Western Offshore Earthquakes
Seriously injured: 50 (approx.)
Injured: Up to 1,000 (approx.)
Damaged buildings: 300 (approx.)
Most damaged area: Genkai Island.
Estimated insurance payouts: 15.8 billion
Legend has it…
Since humanity began, we’ve been concocting interesting explanations for the natural phenomena that affect us. With the benefit of hindsight, some may seem a little eccentric…
Japan- The great catfish Namazu is curled up under the sea with the islands of Japan resting on his back. The god Kashima holds a heavy stone over his head to keep him from moving. Occasionally when the god lets his guard down, the catfish is able to squirm around. This causes earthquakes.
Siberia- In Kamchatka, the god Tuli drives the sled that carries Earth. It is pulled by flea-infested dogs. When the dogs stop to scratch themselves, the Earth shakes.
America- The Gabrielino Indians believe that Earth is carried by turtles on their backs. One day after arguing, three of the turtles decided to swim east, and the others swam west. The earth shook and cracked. They couldn’t swim far because of the heavy land on their backs, so they stopped and made up. But, occasionally, the turtles that hold up the world argue again, and the earth shakes.
Peru- The ancient Maimas believed that earthquakes were caused by the footsteps of a god when he came to earth to count the number of people. Residents wanted to make his job easier and quicker, so they ran from their houses shouting ‘I’m here, I’m here!’. Going outside was a good move; the houses would often have crumbled under the force of the earthquakes.
- There are an estimated two earthquakes every minute around the world.
- The largest earthquake recorded was in Chile in 1960. It was 9.5 on the Richter magnitude scale, caused over 6,000 deaths and triggered a tsunami that affected people here in Japan and Hawaii.
- The earliest known earthquake detection device was invented in 132 A.D. by a Chinese philosopher. It was a large jar with a system of pendulums and carved dragon’s heads that could detect vibrations as far as 600km away.
- Earthquakes are incredibly powerful; on the Richter scale, a magnitude 4 quake will release the approximate equivalent of 1,000 tons of TNT, or a small nuclear weapon. A magnitude 9 quake will release as much energy as around 32 trillion tons of TNT.
You Should Know
There are several guides available that explain what to do before, during and after an earthquake. Everyone should find and read one of these. You can start with the one in this issue! However, I’d like to share some of my experiences and comments.
There are things that you should do before an earthquake. One of the most important is to anchor any unstable things in your home e.g. TV, ornaments, fragile things and anything on the wall. It is not difficult to find clips in the 100 Yen shops to secure your things at home. Never place heavy objects over beds, and keep heavy objects lower than the head height of the shortest member of the family. If you have a desk or table, try to keep the space beneath it empty. During an earthquake, something as simple as a desk can help so much as shelter. When buying a desk, don’t hesitate to pay a little more for a stronger one; it could save your life. Keep your bed away from windows to prevent falling broken glass and before going to sleep, close the curtains. As I said in the beginning, P-waves are the precursor of an earthquake and give you valuable seconds to prepare. It is difficult to recognize them but it is possible. P-waves’ shaking is vertical (up and down) and similar to acoustic waves. If you are near to the source you may hear a loud noise similar to an approaching airplane. Several people who live near Uminonakamichi reported hearing a very strong roaring sound during the earthquake.
During an earthquake, first of all try to stay calm. If it’s at night and you are in bed, get underneath it if possible, or cover yourself with your covers or futon. If you can, get under a strong desk or table. Remember, don’t use the stairs (or an elevator) during an earthquake. If you are in a car try to keep away from underpasses and overpasses, stop in a safe area and stay in the vehicle. Earthquakes that happen at night have more casualties because people are asleep or resting. I remember an earthquake in northern Iran that caused about 40,000 deaths in 1990. In the hospital I spoke to a boy who was the only survivor from a family of eight. He said that as soon as he felt the shaking, all he did was cover himself with his futon. During an earthquake, people are often injured by falling debris or sharp falling objects. As such, something as simple as pulling your covers over your head can help your chances of survival.
Presented here is a snapshot of some of the earthquake-related products readily available in Japan. There are many different items on offer, and we are not recommending any one over the other. Earthquake safety is a serious business, so however you decide to prepare yourself, just make sure you do!
- MUJI Bosai Survival Pack- Be prepared and stylish at the same time! Contains a water-proof radio with mobile phone charger, candles, water preservers, gloves, medical plasters, and much more. 10,500 yen at MUJI
- Emergency Clothes Set- Ultra-compressed set comprising t-shirt, gloves and towel. Very small and light, comparable to the tissue packs given out on the street in size. 1,050 yen at INCUBE
- Emergency Nalgene Bottle Set- Nalgene, the world’s greatest bottle-makers, offer this set complete with survival sheet, poncho, pen-knife, gauze, and more. 5,460 yen at INCUBE
- Anti-Slip Pads- Perfect for stopping your furniture sliding around your faux-wood appartment floors during an earthquake. Could save in damage repair. Medium size: 1,302 yen at INCUBE
- Wind-Up Radio- Can run on batteries or mains, or wind-up in an emergency. Listen to radio for emergency broadcasts, plus recieve TV audio. Comes with built-in flashlight, too. 6,609 yen at INCUBE
- Earthquake Procedures Mug- Contains (in Japanese) important things to remember to survive an earthquake. Drink from it every day and be well prepared! 630 yen at INCUBE
- Pocket Stove- A top seller after last year’s quake, this mini stove cracks open to reveal a store of combustible blocks. Use during an earthquake, when gas is turned off. 945 yen at Ishii Sports
- Freeze-dried Food- Long lasting, light and securely packed, freeze-dried food should always be kept on hand in case of emergency. Large variety available. From 294 yen at Ishii Sports
- Shatter Prevention-A roll of thin plastic for sticking to your windows. Prevents glass from shattering and falling everywhere during a quake. 1,029 yen at INCUBE
- E-Call- An emergency whistle that is so powerful it can be heard up to 700m away. Invaluable should the unthinkable happen and you need to alert others. 567 yen at Ishii Sports
The Fukuoka Bosai Centre - Learn Earthquake Safety and Have Fun, Too!
Don’t be fooled into thinking this place is only for kids. The Fukuoka Citizens’ Disaster Prevention Center presents useful information about disaster safety in a fun and memorable way. Education and practice is the best way to protect yourself, so try the amazing earthquake simulator: a room that shakes up to magnitude 7 on the Richter scale. There is also a typhoon-wind simulator with wind speeds up to 30m/ sec. There’s much more too – fire extinguisher training, emergency procedures training, even first aid training for groups. Visit or call for more details. The Center welcomes international visitors, and information is available in English, Korean, Chinese and French.
Fukuoka Citizens’ Disaster Prevention Center
1-3-3 Momochi-hama, Sawara-ku, Fukuoka
Mon., last Tue. of each month, New Years (12/28-1/4)
Get More Information!
- Fukuoka City Hall (1F) - Visit to get your Earthquake Emergency Procedures booklet in English, Korean, Chinese, Japanese and Portuguese. Located behind IMS Building in Tenjin.
- Rainbow Plaza (IMS Bldg. 8F) - Carries ‘Living in Fukuoka’, a comprehensive guide for foreigners living in Fukuoka (in English, Chinese and Korean), which has a section on Earthquake safety.
- Your Local Ward Offices - Some ward offices carry copies of ‘Living in Fukuoka’ and they should be able to provide you with a Welcome Pack with some useful information when you go through the Alien Registration process.
- Love FM - Turn on your radio for the latest information during a disaster. Love FM (76.1 Mhz, 82.7 in Kitakyushu, 82.5 in Western Fukuoka) offers information in 10 languages. NHK (612 Khz AM, 540 Khz in Kitakyushu- search the web for full listings) offers detailed information in Japanese.
Kego Fault’s Recent Activity: www.hinet.bosai.go.jp/topics/FKO20050320 (J only)
Kyushu University Seismological Group: http://www.sevo.kyushu-u.ac.jp/HYPO/index-e.html
The latest earthquakes in the world: http://earthquake.usgs.gov/eqcenter/recenteqsww/
Earthquake Research Institute of University of Tokyo: http://www.eri.u-tokyo.ac.jp/index.html
Prof. David A. Johnson’s March 2005 Quake Homepage: http://www.seinan-gu.ac.jp/~djohnson/fukuokaquake/
Student of Seismology at Kyushu University