Researchers who analyzed a history of tsunamis along the Pacific coast of Japan’s Tohoku region have learned that seawalls higher than 5 meters reduce damage and death, while coastal forests also play an important role in protecting the public.
The analysis was performed by researchers at Tohoku University, Maryland Institute College of Art, the University of Michigan and Purdue University.
The researchers studied data from tsunamis in 1896, 1933, 1960 and 2011.
“These events have caused large loss of life and damage throughout the coastal region, and there has been uncertainty about the degree to which seawalls reduce deaths and building damage,” said Jeremy D. Bricker, an associate professor in the International Research Institute of Disaster Science at Tohoku University in Japan.
The Japanese have embarked on a 10-year reconstruction project costing about 31.5 trillion yen, or about $255 billion, which includes the construction of tsunami seawalls along Tohoku’s Pacific coast.
The heights and construction methods of sea walls vary widely from one community to another, and even within the same town.
Findings also showed the protective value of coastal “tsunami control” forests.