抄録
Coastal forests that were entirely washed away by the 2011 Tohoku earthquake and tsunami turned into driftwood, increasing the tsunami damage. It is desirable that coastal forests should not be washed away by a tsunami even if they are knocked down. Using Google Earth images and 10-m mesh land elevation data, we investigated the relationship between types of forest damage (washed away or not) and topography in 17 coastal forests that were attacked by tsunamis of 6-16 m in height. In case of a tsunami height of <10 m, either a ground elevation of >3 m at the front of the forest, or an elevation of >1.2 m at the front and an elevation of >2 m at the rear of the forest was essential for coastal forests to not be washed away. In case of a tsunami height of >10 m, 4 factors were important for coastal forests to not be washed away : a ground elevation of >2 m at the front of the forest, a distance of >130 m from the shoreline to the forest, a forest width of >190 m between the front and the rear of the forest, and a ground slope steeper than 0.085 mm-1 from the front to the rear of the forest. These findings can be applied to new countermeasures against anticipated Nankai Trough large-scale earthquakes and tsunamis.
https://ror.org/0447kww10 
