Unit 7 Tsunami Aftermath and Response

1 Introduction to
2 Tsunamis of
   the Past
3 Plate Tectonics
4 Tsunami Generation
5 Tsunami Propagation
6 Tsunami Inundation
7 Tsunami Aftermath
   and Response

7.1 Lesson

Essential Question:
What can we do to minimize damage and prevent loss of life in the future? What lessons can we learn from tsunami survivors?

Enduring Understanding:
Each tsunami event teaches us something: We learn about how natural disasters affect human beings, including risk factors and short and long-term impacts, which helps us prepare for future disasters. Tsunamis teach us about the limitations of resources and technology, and reinforce the need for tsunami preparedness, through education, improved technology and increasingly comprehensive warning systems.

Each tsunami event teaches us something: We learn about how natural disasters affect human beings, including risk factors and short and long-term impacts, which helps us prepare for future disasters. Tsunamis teach us about the limitations of resources and technology, and reinforce the need for tsunami preparedness, through education, improved technology and increasingly comprehensive warning systems.

The 1946 tsunami lead to the development of the Tsunami Warning System. The first tsunami warning center established in the United States was the Pacific Tsunami Warning Center (PTWC) in Ewa Beach, Hawai‘i. The center, originally known as the Honolulu Observatory, was established in 1949 as a direct result of the devastating tsunami of April 1, 1946, triggered by the magnitude 7.4 earthquake in the Aleutian Islands.

Since then, tsunami events continue to spur emergency management agencies and scientists to improve the worldwide Tsunami Warning System. The need for such a system was never more evident than during the December 26, 2004 Indian Ocean tsunami, which caused the greatest damage and loss of life in recorded history: 18 countries around the Indian Ocean were affected by the waves, 297,898 people were killed or listed as missing and presumed dead, well over a million people were left homeless, and the economic losses exceeded $10 billion.

The 2004 tsunami underscored the need for warning centers in the Indian, Atlantic, Mediterranean and Caribbean Oceans and signaled an urgent need for tsunami education and preparedness at local and national levels.

One group of people showed remarkable resilience during the 2004 event, thanks to knowledge passed down from their ancestors, a reminder of the power of knowledge, which may come in many forms.



7.2 Event

The psychological effects of a natural disaster can be long-lasting. Survivors of a tsunami may experience fear, trauma, injury, and grief.

There is no precise timeline to indicate the phases effects that occur in a natural disaster and they vary depending on the type of disaster. However, generally speaking, these phases have been and are observed during and after tsunami events.

Photo by: Centers for Disease Control and Prevention

Catharsis in the Telling

Fusayo Ito survived the May 22, 1960 tsunami that devastated Hawai‘i, but as a consequence suffered from nightmares and feared the sound of water. It took her many months before she could return to the downtown Hilo area. She did not evacuate when warnings sounded, because she had built her house near the place where she had sought safety from the 1946 tsunami and where waves had not previously reached. She was caught by a wave and said, “And then the floor gave way and the house started to go into pieces, I guess, and I just, zoom, went down with the house. And fell right down in the crack. I got stuck. And the house was ‘creak, creak, creak’ cracking around, and the house just collapsed on me and I fainted.” Mrs. Ito woke up and saw the stars as she floated on a window screen in the water full of debris, unable to stand, until the Coast Guard rescued her.

Fusayo Ito found catharsis in sharing her story. In the 1990’s she went to the Pacific Tsunami Museum once a week to share her tale with spellbound audiences of visitors.
Photo by: Pacific Tsunami Museum


Japan 2011

Despite having an excellent early earthquake warning system, the March 11, 2011 Honshu, Japan 9.0 earthquake and tsunami were devastating: 19,263 dead and missing, over $200 billion damage in Japan and $30 million damage in Hawai‘i, and brought worldwide attention to other areas of vulnerability, as with the Fukushima Daiichi nuclear accident, and other post-disaster consequences, including an expensive and lengthy clean up and recovery period.

NOAA and the Smithsonian made a series of videos that made use of some of this footage and reviews how tsunamis are formed, how they travel and how the warning system works.

Video Link One
Video Link Two
Video Linkk Three

Lessons Learned

After the event, researchers sought to understand what had happened among the population during and after the event. Overall there was a high survival rate, 96% in inundated areas of several municipalities studied after the event, attributed to effective education and evacuation procedures.

Several areas of weakness were identified, however. Coastal towns had a minimum of 20-25 minutes to evacuate before the first tsunami wave arrived. What happened?

  • Evacuation maps under-represented the worst case scenario in terms of tsunami inundation and some evacuation centers were not located far enough inland or on high enough ground.

  • Researchers determined that the expectation of official warnings may have slowed evacuation, where natural warnings may have been heeded sooner.

  • Many people died unnecessarily because they took too long to evacuate or did not evacuate due to social or parental responsibility, lack of education or being skeptical of warnings.

  • Walking, running or cycling would have been more effective in saving lives when widespread use of cars and other motor vehicles caused traffic congestion in some areas.

  • Many people returned to the evacuation zone too early, underscoring the need to better educate people that the first wave may arrive later than official estimates, that tsunamis are a series of waves, and that the largest wave may not be the first.


7.3 Aftermath

The destruction wreaked by a tsunami can take months, even years to clean up and rebuilding is expensive and time-consuming. The effects of a tsunami disaster may be structural, physical and psychological and can impact many levels of society from individuals to municipalities and state-level leaders and institutions. The effects, from the trash and debris to the effects on survivors, may be seen and felt for years to come.

Initially, efforts are made to keep people safe and healthy when many areas remain inundated. Buildings may be wrecked or structurally compromised. Survivors live in temporary shelters and are then often moved into more permanent, but still temporary housing as they slowly try to return to a normal way of life. School is interrupted and classes occur in public open places such as gymnasiums.

Cities and broader governments must decide how and where to rebuild and where to allocate finite resources, in an effort to build improved resiliency through better locations and disaster-resilient structures. Seawalls, such as those seen in Japan, are controversial. Some say they helped to blunt the force of tsunami waves and suggest that if they are tall enough, they will be more effective. Others say they contribute to a complacent populace who may not take natural or official warnings to evacuate seriously.


Where Does all the Debris Go?

The March 2011 Japanese tsunami swept an estimated 5 million tons of debris out to sea, with likely about 70% sinking and 1.5 million tons left floating. The debris is difficult to track, and Nikolai Maximenko and Jan Hafner of the International Pacific Research Center (IPRC) at the University of Hawaii attempted to simulate how the debris would disperse using a Surface Currents from Diagnostic (SCUD) model, which makes use of satellite data on sea surface height, ocean surface winds, as well as data from drifting ocean buoys and observer sightings. Eventually most of the debris is predicted to end up in “the garbage patch” that makes the rounds in the North Pacific Gyre. The model shows objects sitting at or just below the water line rather than large objects like fishing vessels, which move at higher speeds with exposed surfaces acting like sails.

Volunteer Efforts

Emergency response and official responses to clean-up are limited. Volunteers can provide much needed support and relief to communities suffering from the effects of a tsunami. Volunteer efforts range from teaching to clean up, to coordinating volunteer work forces and preserving the memories of hard-hit communities.

Engineering Solutions

Is it possible to build structures that may slow down or withstand the force of tsunamis? A tsunami-resistant building would provide a vertical evacuation site in cases of locally-generated tsunamis where there isn’t enough time to move to higher ground or follow evacuation routes to safety. A building must therefore survive the initial earthquake, contain space for evacuees above flood elevation, withstand tsunami-induced forces and battering rams and be fire resistant. Efforts have been made to build houses and structures on stilts, for example, or to change the shape of pilings so that forces associated with tsunamis do less damage to buildings.



Tsunami resilient structures should be reinforced concrete and allow for flow-through if possible. Following the 2004 tsunami, homes on pilings were built in many areas. This type of structure may work for floods and could work for tsunamis if there were no debris in the water. 






Steel-reinforced concrete pilings would seem to be the ideal design for tsunami resilient, but the bent over steel-reinforced concrete pilings of a Samoan falae after the 2009 Samoan tsunami illustrate the complexity of the problem. A common shipping container became the battering ram that took the building down.
Photo by Pacific Tsunami Museum/Walter Dudley

In 2005, tsunami resilient homes were built in Ban Tub Nua, Thailand, but by 2006 residents had filled in lower levels to make use of the extra space, thereby destroying the tsunami resilient design elements.
Photo by Pacific Tsunami Museum/Walter Dudley

7.4 Prepare

Education in schools has been shown to be key in saving lives. Researchers recommend a school-community approach that includes staff, children and parents. It is essential for parents to know that either the school is in a safe location or that staff and children are well-trained in evacuation procedures. This trust may prevent unnecessary risks taken by panicked parents driving through evacuation zones to retrieve their children.


Case Study: Effective Education in Schools, Japan 2011

In Kamaisihi, northeast of Japan, researchers found that the philosophy of tendenko probably played a role in saving lives. Students there had participated in an 8-year tsunami education project that taught the concept of tendenko: in the event of a tsunami, run single-mindedly to high ground and save yourself. Researchers had observed that time and again families would die trying to save each other. The deeply held ties of family and community drew people back into danger and death. Tendenko is predicated on trust: trust that every person will recognize warning signs and work single mindedly to save themselves by moving to high ground as quickly as possible.

At Unosumai, Kamaishi City, all children successfully evacuated the Kamaishi Higashi
Middle School and Unosumai Elementary School, located 800 m inland from the pre-tsunami shoreline following the earthquake. Tsunami evacuation training had been conducted in Kamaishi schools since 2005 and 5-10 hours of annual class time was spent on learning about the tsunami hazard (D. Harding and B. Harding, 2011; MSN Sankei News, 2011). Due to the unexpected height of the tsunami, the children abandoned plans to stay on the 3rd floor of their school building to evacuate uphill, and then had to relocate further uphill twice more during the event. Their training had stressed that they should assess the situation as they see it and be able to respond to changing events, and this most likely saved many lives on March 11th.
(Fraser, S.; Leonard, G.S.; Matsuo, I. and Murakami, H. 2012.)

Tsunami Evacuation Guidlines


7.5 Remember

Tsunami Survivors Tell Powerful Stories

Stories are powerful teaching tools, whether they are passed on through oral traditions or preserved and shared in museums like the Pacific Tsunami Museum. Tsunami survivors’ memories and recounted experiences can teach others about loss, resilience and empathy, and underscore the need for heeding warnings, whether official, unofficial or natural.


"La 'Elima," a Song to Remember

The 1868 earthquake and tsunami devastated settlements along the South Kona coast on Hawai‘i’s Big Island and is commemorated in the popular and haunting mele “La ‘Elima.” Children who were lead to safety in caves were thought to be among the victims, but were rescued five days after the tsunami. Locally-generated tsunamis may be among the most dangerous, as emergency managers may not have the time to issue official warnings. In the event of a strong earthquake, seek higher ground immediately. Local tsunamis may be generated by earthquakes, landslides or volcanic activity.

Click image to enlarge

Preserving Memories

After a tsunami occurs, teachers and students from elsewhere may reach out to sister schools to help commemorate and preserve the experiences of survivors and their families. Projects such as The Memory Project, which reaches out to orphaned children who have experienced significant loss, are one way to foster intercultural exchange. High school students from Ithaca, NY wrote to students in Aceh, Indonesia, whose portraits they painted or drew and through the exchange, learned about the impacts a devastating tsunami can have on individual survivors and their communities.


The Pacific Tsunami Museum

Museums can provide essential information as repositories of tsunami knowledge that value human life and experience. The Pacific Tsunami Museum in Hilo, Hawai‘i, founded in 1993, provides tsunami education to residents and visitors. The museum fosters community skill-building and tsunami education dissemination and serves as a hub for community leaders and emergency managers to strengthen their tsunami mitigation, education and preparedness activities. Tsunami photographs, maps, oral histories, scientific papers, documents, videos and artifacts are archived in the museum.

Mission statement: Through education, no one in Hawai‘i should ever again die due to a tsunami.

Museum outreach projects include an annual Tsunami Story Festival organized around specific themes and remembrances and the Hawai‘i Tsunami Education Curriculum: Kai E‘e, a place-based and culturally relevant education project for Hawaiians and Pacific Islanders funded by the U.S. Department of Education. Education and outreach projects such as these should be ongoing in every tsunami-prone community for the purpose of educating residents and visitors to prepare for the next tsunami.


7.6 Review

Take the following practice quiz to review content covered in Unit 7.

  1. Which tsunami event lead to the development of the official Tsunami Warning System?

  1. How did the people of Simeulue Island, off the west coast of Indonesia, survive the 2004 Indian Ocean tsunami when they were located only 40 kilometers away from the epicenter of the earthquake?
    Thanks to an extensive and efficient official tsunami warning system that included sirens, television and radio alerts, signs leading to safe zones, and yearly evacuation drills in schools.

  1. What was the 96% survival rate of several Japanese municipalities attributed to after the 2011 tsunami event?

  1. What is the philosophy of tendenko, credited in part for successful evacuation of all of the children at Kamaishi Higashi Middle School and Unosumai Elementary School?

  1. Time and again education and training have proven to be the most critical elements in saving lives during a tsunami emergency. What should you do to prepare for the inevitable tsunami that will strike Hawai'i?

  1. What is the safest way to evacuate in the event of a tsunami?

  1. How should tsunami evacuation plans be designed when considering potential effects from an earthquake, such as bridge collapse or downed power lines, and evacuation during inclement weather that has made regular evacuation routes impassable due to flooding?

  1. Why are tsunami survivors' stories important?

  1. Local tsunamis may be generated by earthquakes, landslides or volcanic activity. What should you do in the event of a strong earthquake, once the earth stops shaking?

  1. What is the role of the Pacific Tsunami Museum in Hilo, Hawai'i?