Advances in earthquake and tsunami sciences and disaster risk reduction since the 2004 Indian ocean tsunami
Satake Geoscience Letters
Advances in earthquake and tsunami sciences and disaster risk reduction since the 2004 Indian ocean tsunami
0 Earthquake Research Institute, The University of Tokyo , Yayoi, Bunkyo-ku, Tokyo 113-0032 , Japan
The December 2004 Indian Ocean tsunami was the worst tsunami disaster in the world's history with more than 200,000 casualties. This disaster was attributed to giant size (magnitude M ~ 9, source length >1000 km) of the earthquake, lacks of expectation of such an earthquake, tsunami warning system, knowledge and preparedness for tsunamis in the Indian Ocean countries. In the last ten years, seismology and tsunami sciences as well as tsunami disaster risk reduction have significantly developed. Progress in seismology includes implementation of earthquake early warning, real-time estimation of earthquake source parameters and tsunami potential, paleoseismological studies on past earthquakes and tsunamis, studies of probable maximum size, recurrence variability, and long-term forecast of large earthquakes in subduction zones. Progress in tsunami science includes accurate modeling of tsunami source such as contribution of horizontal components or “tsunami earthquakes”, development of new types of offshore and deep ocean tsunami observation systems such as GPS buoys or bottom pressure gauges, deployments of DART gauges in the Pacific and other oceans, improvements in tsunami propagation modeling, and real-time inversion or data assimilation for the tsunami warning. These developments have been utilized for tsunami disaster reduction in the forms of tsunami early warning systems, tsunami hazard maps, and probabilistic tsunami hazard assessments. Some of the above scientific developments helped to reveal the source characteristics of the 2011 Tohoku earthquake, which caused devastating tsunami damage in Japan and Fukushima Dai-ichi Nuclear Power Station accident. Toward tsunami disaster risk reduction, interdisciplinary and trans-disciplinary approaches are needed for scientists with other stakeholders.
Earthquake; Tsunami; Disaster risk reduction; Tsunami warning system; The 2004 Indian Ocean tsunami; The 2011 Tohoku tsunami
Introduction
On 26 December 2004, five months after the
inauguration of the Asia Oceania Geoscience Society (AOGS),
the countries around the Indian Ocean suffered from
the devastating tsunami. This tsunami, generated by the
Sumatra-Andaman earthquake (magnitude M 9.1), was
the worst tsunami disaster in the world’s written history,
and the casualties were not only from the Indian Ocean
countries but also extended to European countries because
many tourists were spending their Christmas vacations in
Asian countries.
This disaster was attributed to several factors. The
earthquake was huge and such a giant earthquake was not
expected in the Indian Ocean; thus tsunami warning
system did not exist in the Indian Ocean; and consequently
the coastal residents, tourists and governments did not
have knowledge on tsunamis and were not prepared for
such a disaster.
In the last decade, significant improvements have been
made in earthquake and tsunami sciences as well as in
their applications for disaster risk reduction. Scientific
developments include real-time estimation of earthquake
and tsunami source parameters, implementation of early
warning of earthquakes and tsunamis, historical and
geological studies of past earthquakes and tsunamis,
examination of probable maximum earthquake size, long-term
forecast of large earthquakes, new types of tsunami
observations in the open ocean and on the coast, and accurate
tsunami modeling and inversion. The disaster risk
reduction includes delivery of tsunami early warning messages
to officials and coastal residents, making tsunami hazard
maps or probabilistic hazard assessments, construction of
infrastructure such as speakers to disseminate the warning
messages, seawalls, evacuation signs, and designated
evacuation areas, as well as public education. During the
time period of such developments, the 2011 Tohoku
earthquake and tsunami occurred and caused devastating
tsunami damage in Japan and the Fukushima Dai-ichi
Nuclear Power Station accident. Some of the above
scientific developments helped to reveal the source
characteristics of this giant earthquake and tsunami, yet
they could not prevent the disaster.
In this review paper, I first describe the 2004 Indian
Ocean tsunami in section 2, then review developments
in seismology in section 3, followed by those in tsunami
science in section 4. The 2011 Tohoku earthquake and
tsunami are described in section 5. I then discuss efforts
and issues that show how scientific developments can be
utilized for disaster risk reduction in section 6.
The 2004 Indian ocean tsunami
The source of the Indian Ocean tsunami was the
Sumatra-Andaman earthquake on 26 December 2004
(Figure 1). The earthquake size, expressed by a moment
magnitude scale (Mw), was 9.1 (according to United States
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