Study shows higher ground not high enough for some tsunami-prone communities

Kyodo

At least 21 of the dozens of communities in northeastern Japan whose residents had moved to higher ground after being swamped by massive tsunamis in the past were flooded by the March 11 tsunami, officials of the Cabinet Office said at a panel meeting Sunday.

Yoshiaki Kawata, a Kansai University professor who heads the expert panel of the government’s Central Disaster Prevention Council, pointed out the necessity of moving to higher elevations. According to his analysis, most of the 21 communities in Iwate and Miyagi prefectures hit by the recent tsunami were only around 10 meters above sea level.

“Elevations should be sought based on the biggest possible scale (of tsunami). If people compromise and opt to settle in areas close to what used to be urban areas, it could lead to damage on a large scale,” Kawata said.

According to the Cabinet Office, residents in 43 communities moved to higher ground — either collectively or individually — after massive tsunamis triggered by the 1896 Meiji-Sanriku Earthquake, while those in 98 communities, including some of the 43, moved higher after the 1933 Sanriku Earthquake. Following the 1960 Chilean Earthquake, one community found that the ground it was located on had been thrust up to a higher elevation.

The office has found in its study that of those communities, at least 21 also suffered damage from the March 11 disaster, including a district in the town of Otsuchi, Iwate Prefecture.

Only nine communities that moved higher were spared the devastation caused by the recent tsunami waves, including one that now forms a part of the city of Ishinomaki, Miyagi Prefecture.

Kawata noted that the local communities ravaged by the March 11 tsunami may face difficulties in forming the consensus needed if they are to move collectively to a higher location.

Even if some communities do relocate higher, some residents may move back to down again, placing priority on living closer to where they work, he said.