For the second time in the past two weeks, a Niu Valley property has suffered damage from a falling boulder.

The incident, which happened sometime Monday or Tuesday, occurred two houses down from last week's rock fall.

The boulder, measuring 3 1/2 feet by 2 feet, smashed through the property of Glen and Wendy Taira, landing in the family's backyard. Along the way, it damaged a fence and a drain hose that sits about 6 feet from the home, in the 6000 block of Haleola.

Last week, a boulder scraped the side of a home, smashing a gutter, crushing a flower bed, tearing a hole through a cinderblock wall and finally landing on the sidewalk in front.

On Tuesday, the residents of the second damaged home noticed a tear in the fence.

"We saw the hole in the fence yesterday morning. My husband saw something on the side of the house; when he investigated he found the boulder," Wendy Taira said.

"When the first boulder fell last week, there was no break in the fence, so it must have happened sometime early this week," she said. "We called a police officer and asked whether I need to call the Department of Land and Natural Resources. He said the boulder came from a private property owner and that it wasn't their jurisdiction.

"I'm concerned. If it's going to happen it's going to happen, but something should be done about the other rocks," Taira said.

Neighborhood residents are more worried about a boulder they have nicknamed "The Killer." The large boulder, which appears to be the size of a small car, is perched above the homes.

"We estimate it's probably a few tons. It's been up there for the last 20-some odd years since we've lived here. It looks very precarious. The more we look at it, we think it's going to be a real problem when it falls because momentum of that one coming will be worse than the others," Taira said.

Traci Morita, whose parents' family home was struck by the boulder last week, yesterday said the family has been in talks with an insurance company, which is assessing the situation.

The back-to-back incidents illustrate O'ahu's deadly history of rockfalls, which includes the 1999 Mother's Day rockslide that left eight people dead and 50 hurt when tons of boulders crashed into the pool below Sacred Falls.

Other incidents include Thanksgiving Day 2002, when two boulders the size of garbage Dumpsters rumbled down the hillside above the Lalea condominium in Hawai'i Kai, forcing the evacuation of 26 families for 11 months.

Also in 2002 came the death of 25-year-old Dara Onishi, who was killed when a 5-ton boulder crashed into her Nu'uanu bedroom as she slept.

To address the problem, the state is in the middle of a two-year, $14 million plan to reduce the risk of rockslides.