PAHOA, Hawai'i — Civil defense officials and scientists who study Kilauea Volcano stress that the recent flow of lava into the remote Wao Kele O Puna rain forest poses no immediate threat to homes or populated areas, but the lava incursion does have an unsettling aspect to it.

The slow-moving column of molten rock recently ventured into land rated as Lava Hazard Zone 3 under the classification system scientists use to gauge the risk of lava inundation in each part of the Big Island.

By contrast, almost all of the flows in recent years were confined to the riskiest Zone 1 areas that are smack on Kilauea's East Rift Zone, or Zone 2 areas such as land immediately downslope from the rift zone. There are nine zones in all, with Zone 1 being the riskiest, and Zone 9 the safest.

Areas of the Big Island that are classified as Zone 3 include not only Pahoa Village and booming Puna subdivisions such as Hawaiian Paradise Park, but also Hilo, Kea'au, Pahala, Mountain View and Captain Cook.

None of those communities are immediately threatened, and most of those areas are classified as Zone 3 because of risks from lava from Mauna Loa, which isn't erupting. But the incursion of lava from Kilauea onto Zone 3 land underscores the potential for damage in areas that the general public may not regard as particularly vulnerable to volcanic flows.

The flow has moved in the general direction of Pahoa and the rural Puna subdivisions that have been the scene of rapid population growth during a building boom that has lasted for more than a decade.

Jan Ikeda, who manages Jan's Barber & Beauty Shop in Pahoa Village, said the lava flow has sparked much discussion and concern from her customers, but "nobody knows anything about it."

"Nighttime, they go out on the porch and they see the red glow and everything, but they don't know what's happening," she said. "We have a lot of customers, and all day they're saying, 'Let's hope the lava is not coming our way.'

"I guess if we all say our prayers, maybe she'll just stay where she is," said Ikeda, who has her business, her home and land that she owns in the area. "My whole livelihood is here, so naturally we're all worried, but it can happen anywhere. It can go to Hilo."

Big Island residents have been relatively lucky in that most volcanic activity in recent years has been within Hawai'i Volcanoes National Park and in unpopulated areas, said Troy Kindred, administrator of the Big Island Civil Defense Agency. But the new flow serves as a reminder of the risks of living almost anywhere on an island composed of five volcanoes.

"If you want long-term security, life on the side of the world's most active volcano is probably not what you really want," said Jon Olson, who lives in the Leilani Estates subdivision on Kilauea's East Rift Zone.

"Magic always has a price, right? So, we live in one of the most magical places in the world."

LOTS OF HOMES

Big Island Planning Director Chris Yuen said the county estimates there are about 5,000 homes in the Lower Puna subdivisions that include Hawaiian Paradise Park, Ainaloa Estates, Orchidland Estates and Tiki Gardens; and nearly 4,000 more in areas south of that, such as Leilani Estates, Vacationland, Kapoho and Nanawale Estates.

The county approved huge subdivisions in those areas in the 1950s, 1960s and 1970s that had well more than 25,000 lots, and all of that property is now included in Lava Zones 1, 2 or 3.

Yuen said those areas are the fastest growing on the island, with the county issuing about 1,400 building permits in 2005 and 2006 for the area that includes Hawaiian Paradise Park and the areas of Puna south of it. "It's just a huge number of homes that have been built," he said.

The current Kilauea eruption began more than 24 years ago, and its lava flows have usually headed to the southeast. Some of those flows were destructive, and the eruption so far has burned nearly 200 homes and other buildings, including Kalapana Village.

The lava has covered about 29,000 acres, but most of the time the flows headed down the south face of the rift zone through unpopulated areas and continued toward the ocean.

The current flow emerged from a fissure that opened east of Kilauea's Pu'u O'o crater on July 21, collected in a lava "pond," and was released when the northeast edges of the pond collapsed on July 26.

Since then, the lava has been channeled to the north and northeast, according to a new paper prepared on the flow by Jim Kauahikaua, Hawaiian Volcano Observatory scientist-in-charge. Each flow has stalled miles from any populated areas, and scientists don't expect the flow to progress much farther unless there is a significant change.

KEEPING WATCH

To scientists taking the long historical view, the direction the new flow is taking isn't particularly startling. Kauahikaua explains in his paper that much of Puna north of the East Rift zone was covered in a 60-year eruption that took place in the 15th century.

More recently, an 1840 Kilauea flow advanced across what is now the Nanawale Estates subdivision, according to Kauahikaua. That subdivision, which was created in 1960, has almost 4,300 lots on 1,134 acres.

Scientists have set up cameras that monitor the flow 24 hours a day and the county has set up a new Web site to keep people informed. Even so, Kindred said not everyone has a clear grasp of what is going on.

"We get a lot of calls from people who will go outside and see the glow on the horizon," Kindred said. "That's a wake-up call for a lot of people."

Ikeda, the Pahoa Village barber shop owner, and Leilani Estates resident Olson both wondered how the authorities would manage if the lava were to threaten Highway 130, which is the only highway in and out of the area.

Olson said he believes it is just a matter of time until that happens. There has been talk about a second road for years, but nothing has been built.

Reach Kevin Dayton at kdayton@honoluluadvertiser.com.