Resilient Infrastructure
Lessons Learned from the 2011 Great East Japan Earthquake and Tsunami
It has been 10 years since the Great East Japan Earthquake and Tsunami occurred on 11 March 2011. The Association of Pacific Rim Universities (APRU) hosted an event to mark the occasion with four speakers discussing the events of the Tsunami, policy changes, and lessons learned from the catastrophic event. The event included speakers from the International Research Institute of Disaster Science (IRIDeS) at Tohoku University in Japan.
On 11 March 2011, a 9.0-9.1 magnitude earthquake occurred off of the north eastern coast of Japan. This earthquake caused a series of large tsunamis that destroyed much of the north eastern coastline of Japan’s main island. During the tsunami, the Fukushima Daiichi nuclear power plant was damaged. Following 2011, Japan reduced their energy demand on nuclear plants from 20% to a few percent, and the design of cities have changed as well in terms of what types of structures can be built close to coastlines.
~~~~ What Happened? ~~~~
Professor Fumihiko Imamura (IRIDes Tohoku University, Japan) discussed an overview of the events that occurred leading up to the 2011 Great East Japan Earthquake and Tsunami. Japan has an integrated system of sensors and seismic meters around Japan that detect early signs of earthquakes and tsunamis. The combination of sensors work together in conjunction with computer models to function as a tsunami warning system.
According to Professor Imamura, in 2011 the tsunami warning system estimated smaller waves than what occurred. This happened because the system recognized the instantaneous earthquake and issued an alert immediately; since tsunami waves can arrive at the shores before an earthquake is finished, an alert must be sent out quickly in the early stages of the earthquake. The warning system relies on a historic registry of earthquake locations, frequency, duration, and magnitude.
The initial 2011 earthquake lasted three minutes in duration and was one of the most catastrophic earthquakes ever experienced in Japan. At that time the tsunami warning database had about 100,000 models of earthquake samples, damage projections, and size of tsunami generated. Research continues to improve this warning system. During the initial stages of an earthquake, the computer models need to review existing data sets quickly, to determine the areas that will most likely be affected by a possible tsunami.
Following the events of the 2011 tsunami, a new ISO standard on Disaster Risk Reduction was developed. Artificial intelligence and machine learning is a promising technology to help improve the speed at which event outcomes are determined at the onset of an earthquake.
~~~~ Archiving History ~~~~
“While the past doesn’t change, what we think is important about the past changes.” - Professor Andrew Gordon. Professor Andrew Gordon is a historian at Harvard University. He spoke about the importance of archiving, and revisiting historical events to provide new perspective.
One of Gordon’s projects is the Digital Archive Project. This was created to document and archive all kinds of data and information related to major events. The goal was to set up an archive of all the digital records associated with the 2011 Tsunami including items like tweets, and social media posts.
During and immediately after the 2011 Tsunami, lots of materials were archived, but sustaining interest in archiving projects can prove to be challenging. According to Gordon, sustaining interest can be achieved by relating “foreign disasters” to a local scale, and relate previous disasters to ongoing or future disasters in other parts of the world. For example, hurricane prone areas may want to consider how they can react, and rebuild after a devastating event. A digital archive allows the world to learn and prepare for events that have already happened. This can assist with policy development and preparedness in disaster prone areas.
~~~~ Policy and Community ~~~~
Kanako Iuchi (IRIDeS, Tohoku University) spoke about the impact of different policy mechanisms that were used to help rebuild after the disaster. Iuchi spoke about the two approaches typically used in policy making: a top-down approach, and a bottom-up approach.
In a typical response to national emergencies, the national level of government provides funding for infrastructure after a natural disaster (top-down approach). Funds are normally earmarked for specific projects. Letting a community tell a national level what is needed would be considered a bottom-up approach.
One fundamental approach that made the rebuilding unique in Japan was the means by which funds were allocated. In some cases, local governments could apply with a request for funding based on their needs. Two successful examples were shown in smaller communities: Kerobe, Kamaishi and Moune, Kesennuma. The communities determined what was most important for the prosperity of their communities and created a clear list of requirements. In both cases, the locally developed proposals were cheaper and more effective than the original government proposals.
In Kerobe, Kamaishi City, 40% of houses were destroyed by the Tsunami. The initial plan was to build a levee to protect the coastline from future disasters. The local community was strongly against this plan because the levee would impact their biggest industry: seaweed processing. The processing facilities need to be near the shoreline with the ability for machinery and boats to roam freely.
After consultation, a new community redevelopment plan was created, whereby houses were built on higher ground, and the road was designed to be at a higher elevation to act as a levee to protect households. The workplace for the seaweed processing plant was located near the water level. In the event of a tsunami, the workplace could be evacuated, and homes would be protected.
This is an example of a cohesive community clearly voicing their concerns and providing a clear set of priorities needed for their community to thrive. This method is more challenging for larger cities with many leaders of multiple industries, but it is an approach that has shown positive results with the right applications.
~~~~ Hazard Awareness ~~~~
Professor Shunichi Koshimura is a Civil Engineer with the International Research Institute of Disaster Science at Tohoku University. The events of 2011 are considered a super-cycle event, meaning that the earthquake magnitude, tsunami size, and damage was far higher and rare than previous events. The earthquake in 2011 was the fourth most powerful earthquake recorded in history.
Immediately after the tsunami, there was a period of time where it was deemed not safe to enter the area due to debris, downed infrastructure, and ongoing aftershocks. Once deemed safe to enter, damage was surveyed by in-person visits to the areas, and with the use of satellite imagery. In the past ten years, developments in unmanned aerial vehicles (UAVs) and cameras now make it possible for survey’s to be completed regardless of ground conditions.
Coastlines in Japan have hazard maps, which identify high risk areas for tsunamis. These maps can be helpful for development planning, but are not all-encompassing. In 2011, there were areas affected that were not identified on local hazard maps. The hazard maps at the time would not have been able to predict all of the affected areas since the tsunami was a super-cycle event.
The function of a hazard map is to identify high risk areas, but areas not indicated still have the potential for risk, as shown by the events of 2011. Engineering design standards changed after the events of 2011, and construction of large barriers known as seawalls increased around the country. Seawalls are large structures located along coasts, and coves to protect low-lying communities from tsunamis, while allowing ships to pass around the walls.
Earthquake and Tsunami simulation software continues to improve, and provide more accurate disaster modeling. These models help with planning new infrastructure projects that are resilient against natural disasters.
The above photos are an example of a seawall and coastal protection located in Yamaguchi prefecture. The wall acts as a barrier against large waves to protect the cove. Boats can pass freely around the wall. (Cohen, 2018)
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The disaster science community is making continual progress in knowledge sharing about the risks that face countries, cities, and communities around the world. This conference held by the Association of Pacific Rim Universities (APRU) was free for all to attend, and it attracted audiences from around the world.
Warning systems, archiving, policy, planning, engineering standards, and preparedness all have a part to play in the design and continual improvement to healthy infrastructure and communities. In the case of Kerobe, Kamaishi City, a giant sea wall could have been built to protect a city, but changing the location of housing and roadways provided a better solution for the community.
Scientific and engineering communities continue to work to improve the tools that make design of new resilient infrastructure possible. There is still a gap between the sciences and the social sciences, but stories like those from Kamaishi City show that the gap is closing, and great infrastructure can be achieved by engaging directly with the communities they serve.
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Nathan Cohen - May 2021
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You can watch the original presentation 10 years after the Great East Japan Earthquake and Tsunami (session I) online hosted by the APRUSecretariat
The Japan Disasters Digital archive can be viewed online https://jdarchive.org/en
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