A tree on a mountainside outside the boundaries of an artillery range in Fukushima Prefecture is believed to have been the victim of a stray 155-mm howitzer shell from an exercise Friday, Ground Self-Defense Force officials said Saturday.
GSDF officers were investigating whether the errant 60-cm long, 40-kg shell felled the tree on the slopes of the 1,124-meter Mount Kawauchi. The mountain is some 5 km northwest of the GSDF firing range, the officials said.
The GSDF detected the fallen tree from a helicopter during a search operation that resumed early Saturday with 500 personnel.
Some employees at six nearby hot-springs resort reported hearing a loud, heavy sound, they said.
The GSDF said the incident occurred around 3 p.m. Friday and that the howitzer shell was one of four rounds fired during an exercise conducted by the 6th Artillery Regiment, based in Koriyama, in central Fukushima Prefecture. The regiment said it will suspend shelling exercises until the cause of the incident is established.
The firing range straddles the villages of Tenei and Nishigo in southern Fukushima Prefecture. Vacation houses and resorts dot the area, but authorities said there have been no reports of damage or injuries.
The GSDF said the FH-70 howitzer has a maximum range of 30 km. GSDF officials said when used in live ammunition drills, the howitzer is usually aimed at a target about 6 km away, within the 20-sq.-km firing range.
According to GSDF data, debris covers an area about 40 meters by 30 meters when a shell impacts.
The FH-70 howitzer is 12 meters long. It was developed jointly by Britain, Germany and Italy and has been manufactured under license in Japan since 1983.