When Rob Holcombe and his husband bought a studio on Hawaii’s Big Island in 2015, they knew it was in an active volcano zone.
But the Berkeley, Calif., couple had fallen in love with the place and gambled that molten lava would stay away from the forested getaway overlooking the Pacific that Mr. Holcombe describes as a “Garden of Eden.”
“We figured we could get insurance, and it was worth the risk,” said the 52-year-old computer programmer. The couple did get insurance, but it won’t cover much lava damage.
Their second home is one of hundreds threatened by renewed eruption at Hawaii’s Kilauea volcano, which has already destroyed more than four dozen houses and other structures, threatened a geothermal power plant and forced the evacuation of hundreds of residents since May 3.
The properties are in subdivisions built decades ago as part of an ambitious development push by local officials, despite geologic maps at the time that showed the areas were in hazard zones for lava.
An impetus for the development was providing a new revenue source after Hawaii became a state in 1959, said Mary Begier, a realtor in Hilo, Hawaii. At the time, the remote lots weren’t intended to hold homes because they lacked basic infrastructure, she said.
Over time, thousands of homes sprung up as the area, known as lower Puna, became one of the most affordable places to live in the Aloha State. A three-bedroom home there costs as little as $200,000, or about half the $400,000 median home price on Hawaii’s largest island. Some more expensive homes have been built there in recent years.
“It’s easy to say in hindsight we shouldn’t have done that,” Ms. Begier said, referring to the development. “But where would those families be if we had not done that?”
Gavan Daws, a Honolulu-based historian, said developers early on played down the volcanic risk.
“Would you offer land for sale and tell the people there is a volcano and stress the word ‘active’?” asked Mr. Daws, who co-wrote the 1985 book “Land and Power in Hawaii: The Democratic Years,” which chronicles how land projects in the 1950s and ’60s turned lava fields below the world’s most active volcano into subdivisions with thousands of homes.
Daryn Arai, deputy planning director for Hawaii County, said many of the subdivisions in question were created in the 1960s before the county came out with detailed lava-flow hazard maps a decade later. “So I can only assume that these subdivisions were permitted based on the limited information available at that time,” Mr. Arai said.
Lono Lyman, who served as county planning director in the 1980s and manages 4,500 acres of family-owned land in the eruption zone, said shortsightedness on the part of local developers helped drive the development.
“People wanted to make a buck, and it was cheap land being sold,” said the 70-year-old Mr. Lyman. “They saw an opportunity.”
About 200 acres of Mr. Lyman’s mostly agricultural land have been inundated with lava in the latest eruption. But Mr. Lyman played down the impact on his own property, saying he is most concerned for the residents who are losing their homes.
Even some builders say developers never should have built homes in the lava fields. “It was a real lush, green forest, but I don’t think they should have built a subdivision there because there was a lava flow underneath,” said Mark Ferreira, a general contractor in Hilo. “They should have known better.“
Though precise risk-assessment maps didn’t come out until the 1970s, the hazards were well known: Federal officials say lava-flow hazard maps were available for the Kilauea area since the 1940s, and the volcano had erupted at least a dozen times in the century before land sales began in earnest in the 1960s.
“Anybody who lived over there knew very well about the dangers of the volcano,” said George Cooper, a former Hawaii lawyer who specializes in land issues and who co-wrote the book with Mr. Daws. He said many of the initial sales of undeveloped lots were directed at buyers from out of state.
“They thought people would want to buy a piece of Hawaii, and the prices were so low,” said Mr. Cooper, who now lives in Cambodia.
In 1983, after a lull, Kilauea rumbled back to life and has remained in a continuous eruption since. Some communities were inundated by lava soon after, and over the years hundreds of homes have been lost.
What has alarmed local officials this time is the fact that the latest eruption has occurred about a dozen miles away from the previous site, in an area that hasn’t erupted in more than a half-century and where many homes are concentrated.
“This is like a new phase of the long-term eruption,” said Michael Poland, a geophysicist with the U.S. Geological Survey in Vancouver, Wash. “In this area, eruptions tend to last weeks to months. The longer it goes on, the more potential there will be additional areas will be impacted.”
That uncertainty has set the general lower Puna community on edge. Like many home buyers, Mr. Holcombe said he and his husband, Christian Jusinski, were drawn there by the relaxed, junglelike setting. The deck on the two-story home they bought in Puna Beach Palisades for $300,000 overlooks the ocean.
The couple had planned to retire there in a year, but if the home gets swallowed up by lava, their insurance won’t nearly cover the losses, Mr. Holcombe said.
“It’ll be a massive stress in our retirement plans if the house is lost,” Mr. Holcombe said from California. “The loss of the area, the dream, is unimaginable.”
—Jim Oberman contributed to this article.
Write to Jim Carlton at email@example.com