71-year-old Hawaii man dies after falling into lava tube

The last time neighbors saw 71-year-old Robert Hisashi Nishimoto was Saturday, when he was doing yardwork in front of his home in Hilo, Hawaii.

But a friend had not heard from him for days and began to grow worried.

On Monday, the friend called police, who went to Nishimoto’s home and made a startling discovery: while Nishimoto was clipping bushes, he had fallen into a tube created by an old lava flow — more than 20 feet underground — and died.

“It was a hole in the ground less than 2 feet in diameter,” said Lt. Rio Amon-Wilkins of the Hawaii Police Department. “I would assume he stepped on it and went straight down.”

“It does not look like he saw the hole there or he knew the lava tube was there,” he added. “The way the opening looked, it looked like it was probably like dirt, and he just happened to step on this place, and the conditions were as such, that he went through it.”

An autopsy conducted Tuesday found that Nishimoto had died “as a result of injuries consistent with falling,” authorities said.

Police said that Nishimoto did not have any immediate family. Efforts to reach other relatives Thursday night were unsuccessful.

Lava tubes are a ubiquitous part of Hawaii’s landscape, which has been molded by volcanic activity. They are formed during volcanic eruptions when hot lava is exposed to air, cools on the surface and hardens, insulating the lava underneath that continues flowing and creates the tube. The tubes can form in a matter of days.

Some have become tourist attractions, like the Thurston Lava Tube at Hawaii Volcanoes National Park. But the tubes also present a regular hazard and people do fall into them, said Lieutenant Amon-Wilkins. The accidents are rarely deadly.

A firefighter searching for missing pig hunters fell 100 feet into a lava tube obscured by brush in 2002, according to the Honolulu Advertiser. He was hospitalized but survived.

“I know there are lava tubes and caves like that on this island,” Amon-Wilkins said. “We live on an island with an active volcano, and this island was formed from five different volcanoes. This type of thing is extremely rare. I’ve never seen something like this.”

The tubes can be very small or very large, said Janet Babb, a geologist at the U.S. Geological Survey’s Hawaiian Volcano Observatory in Hawaii Volcanoes National Park. She said some tubes were so large that she had heard of bulldozers falling into them. Sometimes pieces of the “roof” of the tube cave in, creating what’s called a skylight.

She said she did not know the circumstances of Nishimoto’s death, but said the USGS had warned people to stay on marked trails in the park to avoid falling into tubes or other cracks in the ground.

Ken Rubin, professor of volcanology at the University of Hawaii at Manoa, said that depending on the landscape and the age of the tube, the ground above it could be brittle or several feet thick. Over time, the tubes become covered in plants and trees, he added.

He said without examining the tube Nishimoto fell into, it was not clear when or how it was formed. But he said it was likely created during a “younger” flow as opposed to one that occurred thousands of years ago. One more recent eruption that could have created the tube came in 1881, when lava from Mauna Loa flowed through what is now Hilo, he said.

He said older tubes tend to get buried or filled in.

When police arrived at Nishimoto’s house Monday, they did not immediately see anything amiss, Amon-Wilkins said. Nishimoto’s home, where he lived alone, looked undisturbed.

Then a patrol officer began exploring Nishimoto’s yard. There was a weed eater and a lawn mower out.

“The officer was just actually looking around in an area, and noticed some newer plant clippings and then came cross the hole,” Amon-Wilkins said.