The enormous tsunami which swept Japan in the March 11th earthquake was an enormous shock to those of us involved in making scientific programming. Every year, NHK's science team had produced programs warning of the fatal dangers of natural disasters: earthquakes, typhoons, landslides. We rang alarm bells hoping to save the lives of viewers. But it was all to no avail, and the tsunami took over 20,000 lives. How can we learn from this tragedy, and pass on those lessons to future generations? What can we bring to the table as makers of science programs? We bent all our energies to the task, with this question ringing in our minds.
Damage in the city of Kesennuma. Image courtesy of Takeshi Shibasaki.
Our first task was to collect the extensive footage of the enormous tsunami, and to thoroughly analyze it. The earthquake had struck in the daytime, so many local residents had captured the tsunami on digital cameras and mobile phones. Minutes after the earthquake, NHK bureaus in the region dispatched camera crews to record the event, and the NHK helicopter was miraculously able to take off from Sendai Airport just before it was consumed by the tsunami. This meant the NHK could secure an unprecedented volume of tsunami footage. Tens of hours of footage were carefully played on a huge screen and we searched for pictured residents who might be able to offer eyewitness accounts.
In particular the clear HD footage captured by a reporter at the NHK Kamaishi bureau shows an astonishing sight. Residents were seen fleeing from homes that were being swallowed up by the tsunami. Immediately after the disaster our team had gone to every evacuation center and residential area with a local map and portable DVD player in hand in order to capture the testimony of those who had, against all odds, survived the onslaught of the tsunami. The extraordinary experiences and bravely captured footage show just how fast the tsunami hit the coast and swallowed up those who had no chance to flee. It is a chilling testament to the destruction and speed of this tsunami.
While gathering residents' testimony, we also examined the captured footage, GPS wave buoy and other records showing tsunami movements. We had decided to attempt the CGI recreation of the tsunami using this data. Having been created offshore, how did its height change, in what order did it hit the coast, and how fast and how far had it come inland? We were certain that answering these questions would be vital to future tsunami planning. We asked the leading scientist in tsunami simulation to handle the calculations, while NHK's CGI team used the resulting data to create top-quality CGI. A particularly useful network came to light: the unattended cameras set up by NHK across Japan, usually referred to as "weather-cams." These cameras recorded everything from the moment after the quake to the coming of the tsunami, with no break. It made it possible to see the tsunami's route and size at any given moment. As many governmental wave gauges set up along the coast were destroyed by the tsunami, this footage was a key component in calculating the tsunami simulation.
Other important factors were the tsunami spawning point and the mechanism by which it was created. A scientist researching seabed faults around Japan gave us data on the position of the fault and the size of the movement which was reflected in the calculations. As they also used geographical data inland, such as elevation and breakwaters, we were able to recreate in detail just how a vast tsunami swept so far inland. It shows exactly how the shapes and depths of coastal bays affected the size and shape of the vast tsunami.
Immediately after the quake, our cameraman and colleague Takashi Hokoi leapt onto a helicopter to shoot the tsunami from above. He explains: "I watched countless tragedies unfold in front of my eyes. One that stayed with me was a man trapped on the bed of a truck. Another was a group of young children stranded on the rooftop of a school building. I was later able to meet them through the program. Despite all our losses, there were some lives saved that day. Being able to share that with viewers has been a great comfort to me."
The analysis of residents' testimony and the footage has shown how evacuating to high ground as fast as possible was vital in saving lives. We must ensure this important lesson is passed on to future generations, and work to minimize any future loss of life. To that end we plan to continue a scientific examination of the earthquake and tsunami. Today Japanese researchers are planning submersible studies and drilling research of the Japan Trench. We hope to constantly follow its movements, and keep viewers informed of the changes occurring beneath our feet. We must give meaning to the many lives taken by the tsunami.
Publicist Note: Surviving the Tsunami airs September 28 on most PBS stations. Please check your local listings to confirm when it will air near you. This program was originally produced and broadcast in Japan by NHK, Japan's public broadcaster.