Environmental Change Risk

TOP > Organization > Hazard and Risk Evaluation Research Division > Environmental Change Risk

Professor: Shunichi Koshimura(Concurrent)
Associate Professor: Keiko UDO
Assistant Professor: Masakazu HASHIMOTO

The Environmental Change Risk Laboratory identifies destructive mechanisms of disasters in coastal areas and rivers, such as tsunamis, storm surges, high waves, flood, droughts and environmental contaminations, in order to quantify disaster risks and develop efficient disaster prevention/mitigation measures. There are concerns about the increase of disasters caused by sea level rise, changes in annual rainfall and glacial melt due to climate change, and these factors are also important subjects of our studies.


Figure 1 Map of the Tohoku region and distributions of downward crustal deformation, tsunami watermark height and seawall height before the earthquake and tsunami, and shoreline retreat due to the event. Significant beach shoreline retreat of several hundred meters and consequent coastal land losses, especially in the vicinity of river mouths and seawall breaches, extended over a large area from Iwate Prefecture to Fukushima Prefecture, causing serious problems in the reconstruction process.  
Figure 2 Curve of beach loss rate in Japan for sea level rise of 0.0 to 1.0 m and future projection of beach loss rate in Japan for sea level rise of 0.6 m. The rate is estimated to be 47% for a sea level rise of 0.26 m (the minimum value of global average sea level rise at the end of 21st century; IPCC, 2013) and 91% for a  sea level rise of 0.82 m (the maximum value of the sea level rise). Beaches are important for disaster mitigation, ecosystem conservation, and tourism. The impact of future sea level rise on coastal areas is significant. 
Figure 3 Detection of disaster damage by automatic digital surface model (DSM) generation using satellite images. Comparison of the histograms of surface object height before and after the 2011 tsunami for each land use shows that the coastal forest and residential district had significant damages.