HILO, Hawai'i — Almost 24 years after the start of the Pu'u 'O'o-Kupa'ianaha eruption of Kilauea, the volcano has become the single sight that most visitors to the Big Island want to see. It also represents a hazard many residents have learned to keep a wary eye on.

Scientists with the U.S. Geological Survey figure the eruption that began on Jan. 3, 1983, is Kilauea's most productive in five centuries. It has covered more than 45 square miles with lava, including almost nine miles of highways, and added about 570 acres of lava land to the Big Island.

It also has destroyed 189 homes and other structures, most of them in the Kalapana area. The last time its scorching lava burned a building was in 2002.

The prolonged eruption was complemented by the dawn of the Internet age, making Kilauea a worldwide tourist attraction for the first time since it rose up out of the sea 50,000 to 100,000 years ago.

WHERE'S THE LAVA?

Now an estimated 2 million people a year visit Hawai'i Volcanoes National Park, and Chief Ranger Talmadge Magno guessed that 90 percent of them come to watch the lava flows.

"The way media gets out nowadays, people track daily what's going on with the volcano," said Magno, who has worked at the park for 14 years. While people used to drop in at the park almost as an afterthought on their tour of the Big Island, "I think now it's a definite destination."

That has been enhanced in recent years with the boom in the cruise ship industry. When the cruise ships dock, there is an extra surge of visitors to the park.

"The whole demographic has changed, the island has just gotten more populated, there's more access to the island with more aircraft, and our tourism is definitely up," Magno said.

For residents, the long eruption taught hard lessons about the risks of living on the volcano's East Rift Zone.

KALAPANA TRAGEDY

Big Island Civil Defense Administrator Troy Kindred remembers going to Kaimu as a boy, and "when I used to go down there, there was just not an awareness of what was on top of the hill there."

When lava from the eruption buried Kalapana, Kaimu Bay and the nearby subdivisions, "that was a tremendous tragedy, I know people down there, people who used to live down there, and that was a very, very difficult and hard lesson," he said.

Vastly improved maps and global positioning systems make it easier to figure out what the risks might be, and people are now "way more akamai about at least assessing" where they are in relation to the rift zone, he said.

"I think that people — Realtors and land purchasers and home builders — are given the opportunity to take a look at where their house is or their potential home, and make an informed decision about buying there," Kindred said.

However, some of these lessons have been learned and then forgotten or overlooked in the past.

BUILDING ON RISK

An eruption along the East Rift Zone destroyed Kapoho Village in 1960, but that same year the county approved the subdivision of Leilani Estates about eight miles away on the same rift zone. That subdivision has 2,266 lots, and building there has accelerated during the recent real-estate boom.

According to the U.S. Geological Survey publication "Volcanic and Seismic Hazard on the Island of Hawaii," Leilani Estates sits in the highest risk zone for lava inundation.

Reach Kevin Dayton at kdayton@honoluluadvertiser.com.