Lava Flow Hazards Zones of Hawaii

What Are Lava Zones?

There are 9 lava zones for the five volcanoes (Kīlauea, Mauna Loa, Mauna Kea, Hualālai, and Kohala) on the Big Island. Per the US Geological Survey, USGS, “the zones, ranked from 1 through 9, represent a scale of decreasing hazard as the numbers increase, based on the probability of coverage by lava flows.

Hawaiian lava flows generally advance slowly and can be easily avoided by people. However, lava flows can destroy everything in their paths—rainforests, buildings, roads, utility and communication systems, and whole communities. During the 1983–2018 eruption of Kīlauea Volcano at the Pu‘u ‘Ō‘ō vent, several people died because of the hazards associated with lava entering the ocean.

The likelihood that future lava flows will interfere with human activity and infrastructure increases as communities and other development encroach on Hawaii’s active volcanoes. USGS scientists characterize long-term lava flow hazards based on where and how often past lava inundation has occurred. When a new lava flow erupts, scientists use different methods to estimate where and how quickly it will travel downslope.

Lava-flow hazard zones vary across the Island of Hawai‘i

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 1800s, 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. The hazard boundaries are approximate, and the change in the degree of hazard is generally gradual rather than abrupt.

Lava flow travel times based on actual flow rates

Travel time estimates for a lava flow are based on the actual advance rate of the flow and, if known, the overall advance rate of earlier lava flows that passed through the same location. However, this method of forecasting travel time is highly uncertain, because factors that control flows are constantly changing—eruption rate, ground slope the flow is moving over, and complex behavior of ‘a‘ā and pāhoehoe flows.

What Lava Zone Is a Property Located?

Looking at Lava Zone maps can be tricky. As stated previously, the boundaries are gradual and not a hard set line. The current lava map is also 20 years old and provides a very broad look at Hawaii Island. Typically, you would need to overlay several maps including the lava zone map to identify if a property is located in a particular lava zone. As a Realtor, I educate Buyers on the areas and where to look based on their level of risk when purchasing. I primarily work with Buyers and Seller in the Kona area, which is on the west side of Hawaii Island.