by analysis of the abovementioned observation data.

## (4) Storm Surge and Denudation Measures

### a. Promoting Storm Surge and High Wave Measures

To protect human lives and assets from storm surges and high waves caused by frequently occurring storm surges, a combination of structural and non-structural measures are being promoted such as the development of coastal levees and the issuing of flood prevention warnings.

### b. Promoting Coastal Erosion Measures

Since a variety of factors contribute to coastal erosion across the nation, the administrators of rivers, coasts, shipping ports, and fishing ports are coordinating to implement measures such as sand bypasses $ {}^{Note 1} $ and sand recycling $ {}^{Note 2} $ .

### c. Providing Disaster Prevention Information Regarding Storm Surges

To enhance disaster prevention activities at municipalities, the Japan Meteorological Agency provides each municipality with storm surge warnings and advisories for individual municipalities.

Also, to assist victims and aid restoration efforts in regions that ground subsidence occurred following the Great East Japan Earthquake, an “Hourly Tide Level Calendar” consolidating astronomical tide level (forecast values for tide level) is published along with other information regarding storm surges.

## (5) Tsunami Measures

### a. Promoting Tsunami Measures

In preparation for the large scale tsunami disasters created by earthquakes such as the massive earthquake which occurs along the Nankai Trough, region building for tsunami disaster prevention through multiple defenses that combine structural and non-structural measures against the biggest tsunami is being promoted through support extended to local governments for matters such as establishing tsunami flooding projections, designating warning areas, and drafting evacuation plans.

For the tsunami measures for coasts, structural measures are taken to develop coastal levees and so on necessary for resisting tsunami with relatively high frequency of occurrence, take earthquake and liquefaction measures, enable automatic/remote operation of floodgates, and develop coastal levees and seawalls with a tenacious structure including various structures such as “green coastal levees” in addition to non-structural measures taken to assist creation of tsunami and storm surges hazard maps and manage and operate floodgates and others effectively. In June 2014, the “Seacoast Law” was amended to improve the coastal disaster prevention and mitigation measures by locating disaster-mitigating forests at the coastal protection facilities which are developed integrally with coastal levees and forcing stipulation of operating rules of floodgates and so on. For the three major harbors where population and functions are concentrated, a study is conducted to ensure a sufficiently high protection level considering the height of tsunami which exceeds the tsunami with a relatively high frequency of occurrence.

For the tsunami measures for harbors, in order to maintain the harbor functions when a large-scale tsunami occurs, development of seawalls with a “tenacious structure”, creation of plans for elimination of obstacles in sea routes (reservation of sea routes in case of emergency), and other disaster prevention and mitigation measures are promoted.

Also, specified ports (86 ports) under the “Act on Port Regulations” have established “Councils on Tsunami Measures for Ships” to further improve tsunami measures for ships at each of the ports with the cooperation of relevant organizations.

For fluvial tsunami measures, in consideration of the liquefaction of levees and tsunami river reversal damages by the Great East Japan Earthquake as well as floodgate operators stricken by disaster, measures such as raising river levees, earthquake resistance and liquefaction measures for levees, automation and remote operation of floodgates are being promoted.