NHK has learned that a survey by a Japanese research institute shows national treasures or important cultural assets at 656 locations across the country are at high risk from flooding or landslides in the event of heavy rain.

The chief researcher at the Nara National Research Institute for Cultural Properties, Takata Yuichi, surveyed properties at 2,585 locations listed in the Cultural Affairs Agency's database, using the Geographic Information System and the land ministry's hazard maps.

The analysis also found that national treasures or important cultural assets in 80 of the locations face a particularly high risk from landslides.

Takata also used a hazard map created by NHK that reflects data provided by municipalities to study areas with a particularly high risk of flooding.

The results show that buildings at 22 locations are in areas that are expected to see flooding of 3 meters or higher.

Takata said recently the number of downpours have increased, raising risks for cultural properties. He said the emphasis has been on measures to safeguard them against fires, but authorities need to take steps to protect them from disasters caused by rain.

Concentrated heavy rain has been observed more frequently in recent years due to reasons including the impact of climate change.

In 2020, the main building of Aoi Aso Shrine in Kumamoto Prefecture, a national treasure, was inundated above floor level.

Last year, the building of the Igarashi family in Niigata Prefecture, a national important cultural property, collapsed after a landslide.