Lessons Learned from Japan’s Earthquakes

Japan is an island country in east Asia, situated in the northwest Pacific Ocean. Japan’s population is equivalent to 1.53% of the world’s total population, with over 125 million people, making it the 12th most populous country in the world. The population density is 876 people per square meter. Three-fourths of the country’s terrain is mountainous, and the rest is coastal plain, which has a highly dense population.

Japan is prone to earthquakes, and that’s because of its geographical location along the Pacific Ring of Fire. It is located where four tectonic plates converge: the Pacific, the Philippine, the Eurasian, and the North American plate, which causes frequent earthquakes. Japan experiences over 5,000 earthquakes a year, but some go unnoticed because of their low magnitude of 3-3.9. Over 150 earthquakes with a magnitude of 5 shakes the Japan archipelago. Japan also has 450 volcanoes, out of which 265 are active, which is 10 percent of the world’s active volcanoes. An earthquake below or close to the ocean triggers a tsunami. 

Japan’s historic earthquakes

The Great Kanto earthquake was the worst in Japanese history and caused 100,000 deaths. Another earthquake was the Great East Japan earthquake that happened on March 11, 2011, which also triggered a massive tsunami on the Pacific coast of northeastern Japan that killed 20,000 people. 

With Japan’s tragic earthquake history, Japan has learned a lot of lessons from its past and has adopted good practices in all other sectors. From its high-tech innovation for resilient infrastructure, disaster management, risk identification, preparedness, and finance management, there is so much for other countries to learn from. Here are some of the things that Japan did for earthquake management:

Disaster planning-

Disasters are uncalled for and unexpected. It’s important to be prepared so it doesn’t cause panic in the system or among the people. Emergency kits are provided to everyone. The government has issued detailed instructions, raising awareness among people and training programs for kids from school. Public access to local evacuation centers and emergency facilities is provided. 

Infrastructure- 

Infrastructure plays a big role in the development of the country, and since Japan is an earthquake-prone area, it’s important to build resilient infrastructure. Earthquake-resistant houses are designed to make In Japan, earthquake-resistant houses are designed to move with the earthquake so that they won’t collapse and cause injuries to people inside.

Earthquake-proof features in Japanese buildings

1. Strong building laws and regulations –

            All structures constructed in Japan must abide by its strict regulations. 

1. Investment-

More investment in infrastructure, as it’s 20% more expensive than the normal cost, but investment in infrastructure is an investment in people. In the long run, it saves from damage and financial disaster. 

1. Innovation- 

High-tech innovation approach to the new structure. 

• Construction material- 

Traditionally, Japan used wood extensively as a construction material. Wood is a highly ductile material; it is lighter, more resilient, and more resistant to bending than steel, stone, and brick. while earthquake vibration energy is high if the building is greater and heavier. 

• The comprehensive strength of wood is 9.5 times higher than concrete and twice that of steel. It’s also four times stronger than steel in terms of tensile strength and 225 times stronger than concrete. When steel and concrete collapse, they can break, while wood is durable and can reclaim its original state. High-rise steel is used for columns and beams instead of reinforced concrete. So as an earthquake-prone country, Japan has made wood and steel a choice for construction materials. 
• Menshin Structure technology:

To reduce the impact of earthquakes, the foundation of the structure rests on steel, lead, or thick layers of rubber, which allow the foundation to move. 

• Taishin structure technology:

beams, pillars, columns, and walls to be constructed at the bare minimum thickness to absorb ground shaking. This is only advised for low-rise buildings because of their aftershocks and repeated tremors. 

• Seishin Structure technology:

Rubber layers, seismic isolators, and shock absorbers are used in high-rises to isolate the building frame from the foundation of the building.

• Use of seismic invisibility cloaks:

      Earthquake energy can be redirected from the structure by burying a cloak of 100 concentric rings of concrete and plastic under the foundation, which force the seismic waves out of the structure.

• Building reinforcement-

Shear walls, diaphragms, cross-braces, moment-resisting frames, and the use of diagonal dampers, especially at the levels of the buildings, are common examples of building reinforcement techniques used in Japan for structures to withstand earthquakes. Shear walls stabilize the structure by supporting tension. Diaphragms help transfer force to the building’s vertical framework, which releases tension from the flooring. 

• Use of dampening in construction-

This reduces the magnitude of shockwaves at the time of an earthquake. 

• Use of pendulums in skyscrapers

      Tall, massive buildings have pendulums in the core, so they sway in the wind and moves in opposite directions to stabilize the building at the time of the earthquake. 

Refrences:

1. World Bank Group (2021) Learning from Megadisasters: A decade of lessons from the Great East Japan earthquake, World Bank. Available at: https://www.worldbank.org/en/news/feature/2021/03/11/learning-from-megadisasters-a-decade-of-lessons-from-the-great-east-japan-earthquake-drmhubtokyo (Accessed: 03 October 2023).
2. JRailPass (2022) Earthquakes in Japan: What to know, JRailPass. Available at: https://www.jrailpass.com/blog/earthquakes-in-japan (Accessed: 03 October 2023).
3. Yvonne (2022) Earthquakes in Japan: Why so common & what to do during one, VOYAPON. Available at: https://voyapon.com/earthquakes-japan/ (Accessed: 03 October 2023).
4. Henriques, M. (2022) How Japan’s skyscrapers are built to survive earthquakes, BBC Future. Available at: https://www.bbc.com/future/article/20190114-how-japans-skyscrapers-are-built-to-survive-earthquakes (Accessed: 03 October 2023).
5. O’Malley, A. (2023) Construction expertise from Japan: Earthquake proof buildings, PlanRadar. Available at: https://www.planradar.com/gb/japan-earthquake-proof-buildings/ (Accessed: 03 October 2023).