10 years on: the 2011 Great East Japan Earthquake and Tsunami
In remembrance, Prof David Tappin discusses the importance of tsunami anniversaries11/03/2021
It is a time for remembrance; on the 11th March 2011 at 2.46 in the afternoon, a 9.1 magnitude earthquake off the east coast of Honshu Island, Japan caused a tsunami up to 40 metres high that flooded local coastlines, causing over 18,500 fatalities and over 280 billion dollars’ worth of damage. This was the most recent devastating tsunami, and its magnitude was a major surprise. Seven years previously, in 2004, in the Indian Ocean, another surprise earthquake generated tsunami resulted in over 220,000 deaths. Afterward, there was still some uncertainty over where these events would strike, and Japan demonstrated that the hazard was global but, also, that their mechanisms (earthquake or submarine landslide) might not be as clear cut as first observations might suggest.
Over the past 20 years there have been a number of devastating tsunamis, which suggests that we are living in the ‘Age of Tsunamis’. Perhaps the first of these important recent events was in 1998, in Papua New Guinea, where 2,200 people died in tsunami up to 15 metres high. Here the earthquake magnitude 7.1 was too small to explain the tsunami height, and for the first time, a submarine sediment failure, termed a slump was proved to explain the tsunami. At that time submarine landslides were not considered effective at causing hazardous tsunamis; and the landslide was identified by new technology available to map the seabed, with the surveys mainly funded by Japan. Six years after the Papua New Guinea tsunami, in December 2004 over 220,000 people died in the devastating tsunami that struck the eastern Indian Ocean. Then in March 2011 the Japan tsunami struck. Here, although the earthquake generated most of the tsunami along the low-lying Sendai Plain, the very high, up to 40 metre elevations, father north along the ‘Sanriku’ coast have been proposed as being from a secondary, submarine landslide. This is still not completely certain, but without the Papua New Guinea tsunami of 1998, it would have been an impossible idea.
The tsunami events of 1998, 2004 and 2011 were catastrophic, with many hundreds of thousands of fatalities, but they all resulted in improved understandings of tsunami mechanisms and tsunami hazard which led to improved mitigation; there are now tsunami warning systems in all the world’s major oceans, whereas in 2004, only the Pacific was covered. The recent earthquake event in New Zealand testifies to the importance of these global warning systems; here there was no dangerous tsunami, but if there had been many lives would have saved.
Our knowledge base today, to plan and respond to tsunamis is far beyond anything considered possible 20 years ago. The result is that all the major ocean basins have warning systems. Devastating tsunami events are, fortunately, quite rare, but not impossible. In this context rather than letting time subdue our memories of these devastating events, anniversaries are important, both in remembering and honouring those who died and suffered in them, but also in reminding us that they will happen again in the future, and when they do we will be aware and prepared. Today’s anniversary of the Japan 2011 tsunami is critically important in this respect.
Tappin, D.R., Evans, H.M., Jordan, C.J., Richmond, B., Sugawara, D., Goto, K., 2012. Coastal changes in the Sendai area from the impact of the 2011 Tōhoku-oki tsunami: Interpretations of time series satellite images, helicopter-borne video footage and field observations. Sedimentary Geology 282, 151-174.
Tappin, D.R., Grilli, S.T., Harris, J.C., Geller, R.J., Masterlark, T., Kirby, J.T., Shi, F., Ma, G., Thingbaijam, K.K.S., Mai, P.M., 2014. Did a submarine landslide contribute to the 2011 Tohoku tsunami? Marine Geology 357, 344-361
David Tappin is a BGS scientist, and Visiting Professor at University College, London, who has researched tsunamis for over 20 years, including those in Papua New Guinea, the Indian Ocean and Indonesia. After the Japan 2011 tsunami struck, he participated in a number of post-tsunami field surveys in Japan and published on the possibility that the tsunami was in part caused by a submarine landslide. Most recently he has researched the Indonesian tsunamis of 2018 in Palu, Sulawesi and the Sunda Strait.
Prof David Tappin
World Water Day 2023: groundwater photo stories
A showcase of groundwater use from around the world highlighting how developing groundwater has benefited the lives of many people.
New seabed geology maps for offshore Yorkshire
Offshore Yorkshire is the latest map to be released in BGS’s series of fine-scale digital seabed maps.
New BGS karst report released for Hampshire and Wiltshire
The report details the evidence for karst processes in areas of soluble rocks that have not previously been considered karstic.
Dr Corinna Abesser appointed BGS Policy Director
Dr Abesser will be supporting BGS staff in the translation of their science outputs to inform policy and regulation as well as advising senior management on policy-related issues.
Melinda Lewis awarded prestigious Whitaker Medal for outstanding contribution to hydrogeology
Melinda Lewis, BGS Honorary Research Associate, has been awarded the Geological Society Whitaker Medal, recognising outstanding long-term contributions to hydrogeology.
BGS welcomes two new board appointments for 2023
Prof Carol Frost, professor emerita of the faculty of geology and geophysics at the University of Wyoming, and Dr Jenny Pyper, former CEO of the Utility Regulator for Northern Ireland and interim head of the Northern Ireland Civil Service, will take up their positions on the BGS Board from 1 March 2023.
Six BGS datasets for assessing shrink–swell subsidence hazards
Shrink–swell subsidence is one of the most significant geological hazards affecting the UK. BGS has six datasets to help assess the problem.
The Kahraman Maraş earthquake sequence, Turkey/Syria
Two large earthquakes occurred within hours of each other on 6 February 2023.
One year on: reflections on the Hunga Tonga-Hunga Ha’apai volcanic eruption
The eruption of the Hunga Tonga-Hunga Ha’apai Volcano in January 2022 has highlighted a global unpreparedness for the impacts from large-scale global events.
New geological map of the Maltese Islands published
The new map, commissioned by Malta’s Continental Shelf Department, is the first update for almost 30 years.
Work complete on 1000 solar panels at BGS
More than 1000 energy-saving solar panels have been installed at BGS’s headquarters in Keyworth, Nottinghamshire.
Updated radon map for Great Britain published
The UK Health Security Agency and BGS have published an updated radon potential map for Great Britain.