Jun Sasaki / Professor / Division of Environmental Studies
Department of Socio-Cultural Environmental Studies / / Coastal engineering, Estuarine and coastal environment, Hydro-environmental engineering

Career Summary
1991: Received B.S. in Engineering (The University of Tokyo)
1993: Received M.S. in Engineering (The University of Tokyo)
1996: Received Ph.D. in Engineering (The University of Tokyo)
1995: JSPS Research Fellow (The University of Tokyo)
1997: Research Associate (The University of Tokyo)
1999: Associate Professor (The University of Tokyo)
1999-00: Visiting Researcher (Asian Institute of Technology)
2002: Associate Professor (Yokohama National University)
2007: Visiting Researcher (University of Florida)
2009: Professor (Yokohama National University)
2013: Professor (The University of Tokyo)

Educational Activities
Graduate School: Coastal Environmental Infrastructure Studies, Environmental Restoration, Rehabilitation and Mitigation

Research Activities
Water quality processes and environmental restoration in Tokyo Bay:
Tokyo Bay is considered one of the most polluted bays in the world, suffering from hypoxia and anoxia from late spring to early fall. The poor water quality can partially be attributed to a reduction in tidal flats and shallow water areas, which have the function of water purification. Restoration of the environment of the bay, including the construction of artificial tidal flats, is currently a major concern. To promote environmental restoration, it is necessary to delineate a picture of the future considering physical, chemical, and biological processes. We are therefore involved in modeling environmental processes and predicting future environments to obtain information that can be used for determining more effective measures and consensus building among stakeholders.

Coastal disaster mitigation:
Tsunamis and storm surges are devastating coastal disasters, especially in Japan and other Asian countries. We have performed tsunami and storm surge disaster surveys for the 2004 Indian Ocean tsunami, the 2006 Java tsunami, the 2010 Mentawai Islands tsunami, the 2011 Tohoku earthquake and tsunami, and the 2013 storm surge Hayan in the Philippines, among others, and have been working on how to mitigate the effects of such disasters. Numerical simulation is a powerful tool for predicting disasters and considering measures. We have adopted a state-of-the-art unstructured grid community ocean model called FVCOM that can finely express bathymetry and topography in coastal areas. Using this model, we have developed a numerical prediction system and applied it to tsunamis and storm surges, including the 2004 Indian Ocean tsunami and the 2011 Tohoku earthquake and tsunami, and intend to use it for potential future tsunamis in Tokyo and Kanagawa. We have also developed a prediction system for the initial spread of radio-nuclei Cs134 and Cs137 caused by the accident at the Fukushima Daiichi nuclear power plant in 2011.

Environmental conservation and sustainable use of mangrove coastal areas:
Mangrove forests are considered valuable coastal vegetation, functioning as a habitat for a multitude of organisms while stabilizing coastal wetlands and mitigating the effects of coastal disasters. The deforestation of mangroves due to, for example, the development of shrimp farming ponds has recently been a serious problem, especially in southeast Asian countries. For sustainable use of mangrove coastal areas, it is crucial to restore mangrove forests and to stabilize coastal lands. To this end, we are currently monitoring mangrove restoration projects using bamboo fences and revetments along the upper Gulf of Thailand and evaluating the different measures used in an effort to come up with better management for sustainable use of mangrove coastal areas.

1) Chen, C., Lai, Z., Beardsley, R.C., Sasaki, J., Lin, J., Lin, H., Ji, R., and Sun, Y.: The March 11, 2011 Tohoku M9.0 Earthquake-induced tsunami and coastal inundation along the Japanese coast: A model assessment, Prog. Oceanogr., 123, 84-104, 2014.
2) Lai, Z., Chen, C., Beardsley, R., Lin, H., Ji, R., Sasaki, J., and Lin, J.: Initial spread of 137Cs from the Fukushima Dai-ichi Nuclear Power Plant over the Japan continental shelf: A study using a high-resolution, global-coastal nested ocean model, Biogeosciences, 10, 5439-5449, 2013.
3) Sasaki, J., Ito, K., Suzuki, T., Wiyono, R.U.A., Oda, Y., Takayama, Y., Yokota, K., Furuta, A., and Takagi, H.: Behavior of the 2011 Tohoku earthquake tsunami and resultant damage in Tokyo Bay, Coastal Eng. J., 54(1), 1250012, 2012.
4) Sasaki, J., Kanayama, S., Nakase, K., and Kino, S.: Effective application of mechanical circulator for reducing hypoxia in an estuarine trench, Coastal Eng. J., 51(4), 309-339, 2009.
5) Rasmeemasmuang, T. and Sasaki, J.: Modeling of mud accumulation and bed characteristics in Tokyo Bay, Coastal Eng. J., 50(3), 277-308, 2008.

Other Activities
Member of Japan Society of Civil Engineers (JSCE)
Executive Chair, Coastal Engineering Committee, JSCE
Member of Japan Association for Coastal Zone Management (JACZS)
Chair, Planning and Management Committee, JACZS
Member of Japan Society for International Development (JASID)
Member of American Geophysical Union (AGU)
Advisory committee member of national and local governments, including Ministry of Land, Infrastructure, Transport and Tourism, Fisheries Agency, Ministry of Environment, Chiba Prefectural Government, and Kanagawa Prefectural Government

Future Plan
My future plan is to continue studying coastal environment, coastal disaster mitigation, and sustainable use of coastal areas in developing countries. I will focus more on environmental restoration measures in polluted bays, including technological aspects, feasibility, and consensus building among stakeholders, which should be balanced with disaster mitigation and public and private use. I am also enthusiastic about accepting more foreign students from developing countries and promoting studies on the coastal problems facing their mother countries.

Messages to Students
One of our missions is to study practical problems in coastal areas and to come up with better solutions. I welcome students from developing countries to join forces with us in our struggle to conserve sustainable coastal areas. Also welcome are students and researchers who are interested in basic studies and pure technologies related to coastal engineering and hydro-environmental engineering, including the development of numerical models and/or the elucidation of physical processes. It is my great pleasure to construct a research network with former students studying in my laboratory.