Improvement of Tsunami Countermeasures Based on Lessons from The 2011 Great East Japan Earthquake and Tsunami — Situation After Five Years

Abstract

The 2011 Great East Japan Tsunami exposed many hidden weaknesses in Japan's tsunami countermeasures. Since then, many improvements have been made in both structural measures (numerical simulations, coastal defense structures, building damage assessment and control forests) and nonstructural measures (warning/observation and evacuation). This review summarizes the lessons and improvements in the five-year time period after the 2011 event. After five years, most of the lessons from the 2011 tsunami have been applied, including more realistic tsunami simulations using very fine grids, methods to strengthen coastal defense structures, building evacuations and coastal forests, improved warning content and key points to improve evacuation measures. Nevertheless, large future challenges remain, such as an advanced simulation technique and system for real-time hazard and risk prediction, implementation of coastal defense structures/multilayer countermeasures and encouraging evacuation. In addition, among papers presented at the coastal engineering conference in Japan, the proportion of tsunami-related research in Japan increased from 15% to 35% because of the 2011 tsunami, and approximately 65-70% of tsunami-related studies involve numerical simulation, coastal structures and building damage. These results show the impact of the 2011 tsunami on coastal engineering related to academic institutions and consulting industries in Japan as well as the interest in each tsunami countermeasure.

Assessment of Educational Methods for Improving Children’s Awareness of Tsunamis and Other Natural Disasters: Focusing on Changes in Awareness and Regional Characteristics in Japan

“…These authors show that awareness of tsunamis on the Sanriku coast was higher because it had been impacted by recent tsunami (in 1896 and 1933) whereas the Sendai coast had not, and infer that this elevated awareness led in most places to more effective evacuation behaviors. A similar conclusion was reached in earlier investigations within the Sanriku region by Ando et al (2013) [8], and in the analysis by Day and Fearnley (2015) [9], who emphasized that prior learning about hazards and evacuation behaviors is essential for effective human evacuation behavior in response to warnings from even the most advanced alarm and defense systems.…”

Numerical Simulations of Large-Scale Sediment Transport Caused by the 2011 Tohoku Earthquake Tsunami in Hirota Bay, Southern Sanriku Coast

“…Suppasri et al, 2016). Therefore, we simulated a scenario in which the first and second dikes did not break.…”

Development of a Tsunami Inundation Analysis Model for Urban Areas Using a Porous Body Model

“…Tsunami predictions in urban area have been conducted by using several kinds of models [4]. For example, Arikawa and Tomita [5,6] coupled a Storm surge and Tsunami simulator in Oceans and Coastal areas (STOC) [7] and a Super Roller Flume for Computer Aided Design of Maritime Structure in 3D (CADMAS-SURF/3D) [8] using a volume of fluid (VOF) method to efficiently simulate tsunamis from the source to run-up in both directions, and Suwa et al [9] also developed a model integrating a Smoothed Particle Hydrodynamic (SPH) method and a two-dimensional nonlinear shallow water wave (NSWW) model (TUNAMI-N2 [10,11]).…”