Earthquake-proofing your furniture

Since its publication in March 2005, this forecast has undergone repeated improvements in seismic motion prediction methods and underground structure models, and the forecast from April last year was revised, with the probability now higher for the majority of cities. Looking at prefectural capitals, the range is from 0.7% in Morioka to 89.5% in Shizuoka, with Tokyo at 19.7%, Osaka at 59.5%, and Nagoya at 44.4%. If the probability is relatively high, it will increase a little each year. How to interpret the predicted probability is a tricky issue, but the Headquarters for Earthquake Research Promotion considers 0.1% to 3% to be slightly high, and 3% or more to be high.

Assuming we are to be hit by an earthquake of magnitude 6-weak within the next few decades (perhaps tomorrow), I would like to emphasize three points for further promoting earthquake countermeasures: (1) adoption of designs that will cause no damage in an earthquake of magnitude 6-weak, (2) the urgency of seismic assessments and seismic reinforcement, and (3) earthquake countermeasures for furniture and fixtures.

The current Building Standards Act assumes a rare earthquake of intensity 5 or so, with the goal of no damage. It also assumes an extremely rare earthquake of intensity 6+ to 7, with the goal of no fatal damage such as collapse. As a result, buildings constructed under the current Building Standards Act may suffer various damages, even if they do not suffer fatal damage, in a case of intensity 6 or so. Of course, this is not the case for all buildings, and damage will be small for buildings designed to have a high level of damage resistance, such as high-rise buildings and buildings that incorporate seismic isolation and vibration control structures. If we are prepared to be hit by an intensity 6 or so within the next few decades, construction costs will increase somewhat to ensure no damage. However, the increase will be less than the cost of repairs and compensation after damage.

Buildings constructed before 1981, when the current Building Standards Act did not apply, may or may not suffer fatal damage such as collapse in an earthquake of magnitude 6. In order to prevent fatal damage, it is necessary to carry out earthquake resistance inspections and reinforce the buildings as necessary. Even if reinforcement is not possible, the worst damage can be prevented if you have the knowledge of what will happen and where the dangers are.

When preparing for an earthquake with a seismic intensity of 6 or less, it is also important to prevent injuries. Even if injuries occur, if they cause problems in recovery activities and daily life after the earthquake, the impact will be immeasurable. The overwhelming majority of injuries occur due to furniture falling over or moving. Damage caused by furniture during major earthquakes has been widely known through re-enactment experiments using a large shaking table called E-Defense and experiences using a shaking vehicle, but if the earthquake is a seismic intensity of 6 or less, the damage will be devastating. Furniture with casters will move around, and tall furniture will fall. Lighting fixtures hung from the ceiling will swing and hit the ceiling. Items placed on top of dressers and other furniture will fall. Televisions placed on a stand will fly away. Now that we understand the need to prevent furniture from falling over or moving, what should we do in reality? You may hesitate because you don't want to damage furniture or buildings, or because it looks bad, but I would like to advise you to consider various countermeasures before making a decision. For example, in the case of a problem of preventing a television placed on a stand near the sleeping area from hitting the sleeping area directly. The basic idea would be to fix the TV to its stand, but other options include lowering the TV, raising the bed, installing an emergency earthquake warning on the TV, getting a smaller TV, moving the TV farther away, or throwing it away. If you come to the conclusion that fixing the TV is the only option after all, then it makes sense, doesn't it?