Why is Kalapana (an area inundated by lava in 1990) in Zone 2, while Leilani Estates (which has not as recently been inundated) is in Zone 1?

Kalapana is about 13 km (8 mi) downslope of Kīlauea’s east rift zone. During Kīlauea’s current east rift zone eruption, lava flows took 6 years to first reach Kalapana (in 1989) before the area was more completely inundated with lava over a period of about 9 months in 1990. Lava flows then spared this area for 20 years, until they once again threatened Kalapana Gardens in 2010-2011.

Leilani Estates, on the other hand, is located entirely on Kīlauea’s lower east rift zone, and the next eruption in this area could start within, or immediately adjacent to, the subdivision. The most recent lower east rift zone eruptions were in 1955 (left), when one of the vents erupted lava along the southernmost boundary of Leilani Estates, and in 1960, when lava inundated the village of Kapoho.

There is evidence of eruptive vents both north and south of Leilani Estates. But, unfortunately, many of the volcanic features indicative of the active rift zone—craters, cinder cones, steaming vents—are disguised by lush vegetation or have been removed by quarrying or grading, which leads to a false sense of security.

The concern is that when—not “if”—the next eruption occurs on Kīlauea’s lower east rift zone, active vents and lava flows will directly impact Lelani Estates, and will do so for as long as the eruption continues. Thus, the Zone 1 designation for the subdivision is appropriate.