Earthquakes are unexpected and unavoidable disasters. Many researchers have tried to predict the time and magnitude of great earthquakes, but it has been an impossible task so far. Thus, disaster mitigation, and not prevention, has become Japan’s main focus since 2008. The concept of mitigation is to decrease, avoid, and control the damage of natural disasters, such as earthquakes and tsunamis. In wake of this, the Japanese government published a guide for disaster mitigation. The mitigation guide stresses the importance of communication within neighborhoods, the knowledge of evacuation sites, etc., but most importantly, in my opinion, the guide stresses the evaluation of the strength of buildings and the importance of built-in furniture. Of course the advice to citizens in the guide is helpful and important, but it’s going to be nowhere near as effective in saving lives as focusing on the evaluation of building structure, safety, and natural disaster withstanding, which, in less technical terms, is “getting at the route of the problem.”
One of the most popular new structure systems is ‘base isolation,’ usually used for skyscrapers. According to “Seismic Base Isolation Technique for Building Earthquake Resistance,” “The concept of base isolation is explained through an example building resting on frictionless rollers. When the ground shakes, the rollers freely roll, but the building above does not move. Thus, no force is transferred to the building due to the shaking of the ground; simply, the building does not experience the earthquake.” Though higher floors will shake more than lower ones, the building has a much greater chance of withstanding the earthquake.
Another popular technique is the ‘damping structure,’ also used for huge-sized buildings, such as apartments and public institutions. Satuya Soda, a doctor of engineering at Waseda University, expresses, “The term high-damping structure as used here refers to a structure equipped with dampers [link on further explanation of dampers below] designed to absorb seismic energy and to protect the main structural members from significant damage, even when exposed to an extremely strong earthquake ground motion.” Additionally, since damping structure is cheaper than base isolation, this technique, though not yet common in houses, is in the process of being directed towards the housing market.
The above two mentioned techniques are the most commonly used earthquake damage prevention techniques used in Japan, though not the only ones. Additionally, Japan has adapted its basic architectural materials and design to cope with natural disasters.
“An Update on Building Damage from the Tohoku Earthquake”: http://japanpropertycentral.com/2012/02/an-update-on-building-damage-from-the-tohoku-earthquake/
Seismic Base Isolation Technique for Building Earthquake Resistance: http://articles.architectjaved.com/earthquake_resistant_structures/seismic-base-isolation-technique-for-building-earthquake-resistance/
High-damping Structure Systems to Improve the Seismic Safety of Buildings and Houses: http://www.sci.waseda.ac.jp/english/researchprofiles/creative/subject01_4.html