More than 60 percent of municipalities in the northeastern prefectures of Iwate and Miyagi do not plan to relocate their city or town halls despite being designated as areas at risk of flooding in the event of a large-scale tsunami, a Kyodo News survey showed.

Eleven out of 18 municipalities, which were severely damaged in the March 2011 earthquake and tsunami disaster, are instead taking precautions against natural catastrophes by moving their disaster-response capabilities to higher ground, according to the survey.

Photo taken in February 2022 from a Kyodo News helicopter shows the town office of Onagawa (top C) in Miyagi Prefecture. (Kyodo)

The municipalities are drawing lessons from what happened in disasters in recent years including in 2011 when municipal offices were damaged and many officials were killed.

Similar situations also occurred in 2015 when torrential rain triggered floods in eastern and northeastern Japan and in 2016 when twin megaquakes hit Kumamoto and neighboring Oita prefecture in southwestern Japan.

As the offices were unable to function properly, the local governments subsequently failed to function properly and their initial responses and support for victims were delayed.

Following the 2011 enactment of a law on community development to prevent tsunami disaster, Iwate, Miyagi and Fukushima prefectural governments released forecasts on areas at risk of flooding in case of a large-scale tsunami by 2022. The data covered 37 municipalities.

Kyodo News surveyed the 37 municipalities in January to February this year, and found that nine municipalities each in Iwate and Miyagi had offices in areas that could flood, while Fukushima had none.

Of the nine in Miyagi, four municipalities, such as the town of Onagawa, suffered damage from the tsunami and had just relocated their offices. But they were still in areas vulnerable to flooding.

When the 37 municipalities were asked if they planned to relocate their offices given their location, just two said they would while 11 said they had no plans.

Among the reasons not to relocate, Otsuchi town in Iwate said it plans to move to a facility on higher ground when the tsunami warning is issued, while Ishinomaki city in Miyagi said it plans to respond from a center located on the second floor and above that they hope will be safe.

Others said they could still maintain operations as the flooding is not expected to be severe.

In the survey, five municipalities said they were undecided about relocating. Of them, Kuji city in Iwate said it is considering whether relocating is necessary.

The designation of areas at risk of flooding was made on the assumption that a powerful quake similar to the magnitude-9.0 that hit eastern and northeastern Japan on March 11, 2011 or a megaquake in the Japan and Chishima trenches off the country's northern Pacific coast had occurred, coupled with adverse conditions such as high tides and the collapse of breakwaters.

Among the designated areas, the maximum immersion depth is expected to be 9.06 meters in Kamaishi, 7.8 m in Noda, 6.9 m in Otsuchi, 6.85 m in Kuji, all in Iwate Prefecture. In Miyagi Prefecture, the highest depth is assumed to be 3.82 m in Onagawa.

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