Elderly man who fell, died in lava tube identified

Local News

The elderly man that fell into a lava tube and died on his property has been identified as 71-year-old Robert Hisashi Nishimoto.

Police responded to a report of an elderly man who had not been seen or heard from in several days. Upon arrival, police located Nishimoto and Hawaii Fire personnel were called to assist in retrieving the victim.

It appeared Nishimoto had fallen through a soft area of ground into the lava tube.

His closest friends told KHON2 that they knew something was wrong when Nishimoto failed to show up for lunch on Monday afternoon.

“We waited for him and he never showed up, which is really unlike him because usually he’s early and if he’s not coming he would call us,” said his best friend Richard Mashiyama.

After texting Nishimoto with no response, Mashiyama and another friend drove to his house and saw first responders recovering Nishimoto’s body.

Hawaii Island police say Nishimoto was likely tree trimming in his yard when he fell through a soft area of ground into a lava tube. 

Mashiyama heard that he was last seen by a neighbor in his yard on Saturday.

“Hopefully, if it happened on Saturday, he was dead from Saturday— I sure hate to think he suffered.” He said.

The incident happened in the Kaumana area in Hilo.

Experts said the tube located near Kaumana Cave, a very large public lava tube, was most likely created during the 1880-1881 Mauna Loa lava flow.

A lava tube forms when the surface of the flow and the bottom of the flow solidify but the middle part stays molten, explained one UH geologist.

“Lava can continue to flow through that middle part and that’s how lava manages to get from the vent to the front of the flow where it’s advancing over the ground in a pahoehoe lava flow—so they’re very common,”  said Scott Rowland, a geologist at the University of Hawaii Manoa.

Rowland said Nishimoto likely fell through a skylight, which is a hole in the ceiling of the lava tube.

“Skylights form naturally either during the eruption or after the eruption,” said Rowland.

“If the whole area is overgrown and you can’t really see where you’re walking, then it’s hard to tell,” he explains.

He said tall trees can even grow out of skylights. “So if it’s an old flow, the trees may actually have their bases in the skylight and coming out of it.”

He said the skylight in Nishimoto’s yard could have always been there but hidden, or it recently formed.

“Rocks are not static, things do change,” he said. “If there are earthquakes perhaps rocks get weaken a little bit or if there’s a heavy rain then soil that might have helped block a pre-existing skylight might get washed away or into the tube.”

“It is rock on the bottom and likely uneven and jagged so yeah it’s definitely serious if one falls into a skylight,” he said.

He warns people who live or walk near previously active lava flows to watch their step.

“Again if it’s covered with brush it may be hard to find or see,” he said.

Nishimoto’s friends say he was a former USC professor who loved to travel all over the world and that he will be missed.

Nishimoto was transported to Hilo Medical Center where he was pronounced dead. An autopsy determined Nishimoto died as a result of injuries consistent with falling.

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