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Maps showing volcanic hazard zones on the island of Hawai`i were first prepared in 1974 by the U.S. Geological Survey and were revised in 1987. The current map shown below, divides the island into zones that are ranked from 1 through 9, based on the probability of coverage by lava flows. Other direct hazards from eruptions, such as tephra fallout and ground cracking and settling, are not specifically considered on this map; however, these hazards also tend to be greatest in the areas of highest hazard from lava flows.

Hazard zones from lava flows are based chiefly on the location and frequency of both historic and prehistoric eruptions. Historic eruptions" include those for which there are written records, beginning in the early 1800's, and those that are known from the oral traditions of the Hawaiians. Our knowledge of prehistoric eruptions is based on geologic mapping and dating of the old flows of each volcano. The hazard zones also take into account the larger topographic features of the volcanoes that will affect the distribution of lava flows. Finally, any hazard assessment is based on the assumption that future eruptions will be similar to those in the past.

Hazard zone boundaries are approximate. The change in the degree of hazard from one zone to the next is generally gradual rather than abrupt, and the change can occur over the distance of a mile or more. Within a single hazard zone, the severity of hazard may vary on a scale too fine to map. These variations may be the result of gradual changes that extend across the entire zone. For example, the hazard posed by lava flows decreases gradually as the distance from vents increases. There may be abrupt changes, however, in the relative hazard because of the local topography. For example, the hills behind Ninole stand high above the adjacent slopes of Mauna Loa and consequently are at a much lower risk from lava flows than the surrounding area, even though the entire area is included in a single zone. To determine the hazard differences within a single zone, more detailed studies are required.

Hazard Zones for Lava Flows on the Island of Hawai`i

Hazard zones from lava flows on the Island of Hawai`i are based chiefly on the location and frequency of historic and prehistoric eruptions and the topography of the volcanoes. Scientists have prepared a map that divides the five volcanoes of the Island of Hawai`i into zones that are ranked from 1 through 9 based on the relative likelihood of coverage by lava flows.

Zone Percentage of area covered by lava since 1800 Percentage of area covered by lava in last 750 years Explanation
1 greater than 25 greater than 65 Includes the summits and rift zones of Kilauea and Mauna Loa where vents have been repeatedly active in historic time.
2 15-25 25-75 Areas adjacent to and downslope of active rift zones.
3 1-5 15-75 Areas gradationally less hazardous than Zone 2 because of greater distance from recently active vents and/or because the topography makes it less likely that flows will cover these areas.
4 about 5 less than 15 Includes all of Hualalai, where the frequency of eruptions is lower than on Kilauea and Mauna Loa. Flows typically cover large areas.
5 none about 50 Areas currently protected from lava flows by the topography of the volcano.
6 none very little Same as Zone 5.
7 none none 20 percent of this area covered by lava in the last 10,000 yrs.
8 none none Only a few percent of this area covered in the past 10,000 yrs.
9 none none No eruption in this area for the past 60,000 yrs.

Hazard zones for lava flows on Kilauea Map of hazard sones for lava flows on Kilauea

The flows erupted since 1800 are shown in gray and dated. Twenty-eight percent of the area encompassed by Zones 1 and 2 on the east half of the volcano has been covered by lava since 1955. The major housing subdivisions on the slopes of the volcano are shown in green.

The hazard map for Kilauea shows the relative degree of hazard from lava flows for different areas of the volcano. Zone 1 is the most hazardous; it consists of the summit area and rift zones because Kilauea's frequent eruptions originate in these areas.

Zone 2 includes the areas that are adjacent to, and downslope from, the east rift zone. The entire area south of the east rift zone lies in this zone. Lava flows are most likely to travel in this direction because the ground slopes downhill from the rift zone to the ocean. The area north of the lower east rift zone, which includes Pahoa, is also in Zone 2. Here the land slopes away to the north as well as the south, and flows can advance in either direction. 

Zone 3 includes the areas north of the upper east rift zone and both north and south of the southwest rift zone. Less than 5 percent of the area in Zone 3 has been covered with lava in historical time, but more than 75 percent has been covered in the last 750 years.

No area on Kilauea is ranked Zone 4, but the area south of Kilauea's summit is classed as Zone 5. This flank of Kilauea is currently protected from lava flows by the location of the summit caldera and by north-facing fault scarps (steep slopes or cliffs that form as the result of movement along faults). Because of those topographic barriers, almost none of this area has been affected by lava flows during historical time, although nearly half of it has been covered within the last 750 years. 

Hazard zones for lava flows on Mauna LoaMap of Mauna Loa lava flow hazard zones

The flows erupted in the last 150 years are shown in gray and dated. The major housing subdivisions are shown in green.

Zone 1 on the lava flow hazard map for Mauna Loa includes the summit region and the recently active parts of the rift zones.

Zone 2 consists of areas on both sides of the northeast and southwest rift zones. Since both of Mauna Loa's rift zones form prominent ridges, all the areas in Zone 2 are downslope of potential eruption sites. About 20 percent of this area has been covered by lava in historical time, 5 percent since 1950.

Zone 3 includes other areas on Mauna Loa in which the hazard is gradationally lower than in Zone 2. During the past 750 years, lava flows have covered about 15 to 20 percent of Zone 3 on Mauna Loa. These areas are less affected by rift activity than Zone 2, although the area of Zone 3 that lies on the northwest flank of the volcano is vulnerable to eruptions originating at vents on that flank. The 1859 lava flow covers 10 percent of this area. The part of Hilo that lies south of the Wailuku River is included in Zone 3 of Mauna Loa.

Two areas on Mauna Loa are classed as Zone 6 because they are currently protected from lava flows by the local topography. One of these is the Naalehu area; the other is the slope southeast of the present summit caldera.

Between 1868 and 1950, lava flows from the southwest rift zone reached the ocean during five eruptions. Flows from four of these eruptions traveled to the sea in 3 to 48 hours. Since 1900, Mauna Loa has erupted 15 times, with eruptions lasting from a few hours to 145 days. After the 1950 eruption, Mauna Loa was quiet for 25 years. It reawakened with a 1-day summit eruption in 1975.

The most recent eruption of Mauna Loa occurred in 1984. This eruption originated at the summit and, within a few hours, migrated to the northeast rift zone. The resulting lava flows advanced to within 4 miles of Hilo before the 3-week-long eruption ended.

Hazard zones for lava flows on Mauna Kea and KohalaMap of lava flow hazard  zones of Mauna Kea and Kohala 

The summit and upper slopes of Mauna Kea comprise Zone 7 on the lava flow hazard map. Lava covered about 20 percent of this zone in the last 10,000 years.

Zone 8 includes the lower slopes of Mauna Kea. Most of this area has not been affected by lava flows for the past 10,000 years. The part of Hilo that lies north of the Wailuku river is within this zone.

Zone 9 consists of Kohala, the oldest volcano on the island, which last erupted about 60,000 years ago. Although it is impossible to know if this volcano is extinct or only dormant, the volcanic hazard there is extremely low.

Hazard zone for lava flows on Hualalai

Map of lava flow hazard zones of Hualalai

The entire volcano comprises Zone 4.

Hualalai is much older than Kilauea and Mauna Loa, and its eruptions occur far less frequently. In the last 3,000 years, Hualalai has erupted near its summit, along the northwest and south-southeast rift zones, and from vents on the north flank of the volcano. Twenty-five percent of the volcano is covered by flows less than 1,000 years old.

Hualalai last erupted in 1800-1801 from several vents on the northwest rift zone. Large flows spilled down both sides of the ridge formed by the rift zone and quickly reached the ocean. One of these flows lies south of Kiholo Bay, and part of the Kona Village resort is built upon it. Another flow underlies the northern end of the Keahole (Kona) Airport. Other major eruptions occurred about 300 and 700 years ago. A large flow from the 700-year-old eruption forms the north side of Keauhou Bay, south of Kailua.

All of Hualalai is included in Zone 4. The flanks of the volcano do not have a distinctly lower hazard than its rift zones because the distance from the vents to the coast is short and the slopes are steep.

Which subdivisions are in each lava hazard zone?

Lava Zone 1

  • Leilani Estates
  • Kapoho (some areas, but not everything)

Lava Zone 2

  • Black Sand Beach
  • Nanawale Estates
  • Hawaiian Beaches and Shores and Parks
  • Kapoho (some areas, but not everything)
  • Kehena
  • Puna Beach Palisades
  • Kalapana Seaview Estates
  • Kaimu-Makena Houselots

Lava Zone 3

  • Ainaloa
  • Tiki Gardens
  • Hawaiian Paradise Park
  • Hawaiian Acres
  • Fern Acres
  • Fern Forest Estates
  • Volcano and all of Hilo town