ports, and fishing ports are coordinating to implement measures such as sand bypasses $ ^{Note 1} $ and sand recycling. $ ^{Note 2} $

## ③ Providing Disaster Prevention Information Regarding High Tide Levels

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

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 high tide levels.

## (6) Tsunami Measures

## ① Promoting Tsunami Measures

In preparation for the largest scale tsunami disasters following great earthquakes along the Nankai Trough, building regional tsunami disaster prevention through multiple defenses combining hard and soft measures against the biggest tsunamis is being advanced and regional authorities are being supported for measures such as establishing tsunami flooding projections and drafting evacuation plans.

Also, as a lesson from the Great East Japan Earthquake, relevant ministries and agencies worked closely to reevaluate the hazard map creation manual.

For tsunamis with a comparatively high rate of occurring (once every several decades to every one hundred and several decades), coastal levees are being developed along with earthquake resistant measures. In case of occurrence, coastal levees and breakwaters with a structure that steadfastly maintains effectiveness even when the tsunami flows over the levee crown will be developed and at the three major ports where population and functions are concentrated, protection standards reflecting the likelihood of high tsunamis with a comparatively high rate of occurring will be evaluated and also the automation and remote controllability of floodgates and land locks will be promoted.

Also, specified ports (85 ports) under the “Act on Port Regulations” have established a “Council 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 will continue to be promoted.

For the four river systems in the Tohoku Region, the lessons learned from the Great East Japan Earthquake will be applied to the formulation of earthquake and tsunami measures, geographic changes to the surrounding river mouth area such as land subsidence following earthquakes will be reflected in changes to the “Basic Policy for River Improvement” and the “River Improvement Plan” that follows the basic policy will be formulated and changed, and initiatives for regional reconstruction and town planning such as the development of river levees in the river mouth area will be promoted in coordination with the region.

For the tsunami measures of airports, in preparation for great earthquakes along the Nankai Trough, for airports that may be affected by tsunami disasters, the formulation of tsunami evacuation plans for the protection of human lives was carried out. Following this, rapid restoration measures to restore airport functions as soon as possible in the event of a tsunami disaster will be evaluated.

For the tsunami measures of railways, the conditions of evacuation guidance when tsunamis occurred after the Great East Japan Earthquake will be inspected and fundamental thinking for evacuation (speedy evacuation is the most effective and important measure, etc.) for the largest scale tsunamis following something like the great earthquakes along the Nankai Trough will be reflected in the response guidelines and case studies compiled for passenger railways to secure safety when tsunamis occur to promote initiatives by railway companies.