Volcano Watch — Hazards of lava viewing

The eruption along Kīlauea's East Rift Zone continues with little change from past weeks. The lava is transported underground in a tube from the active vents on the flank of the Pu'u'O'o cone to the ocean at Kamokuna along the eastern side of the active flow field.

There are many hazards around the active lava flows and at the ocean entry. Despite repeated warnings over many years about these hazards, we often encounter people on the flow field who have placed themselves in great jeopardy by entering these hazardous areas.

The area inside Hawaii Volcanoes National Park where the flows are currently active is closed because of the many hazards. Park rangers issue citations to people who enter this area. The bulldozed road from Kalapana to Royal Gardens subdivision is controlled by Hawaii County Civil Defense, and access is limited to area residents and to scientists. Despite these restrictions and the long, hot hike into the area, we continue to encounter people close to the active flows.

The natural hazards they encounter near the flows are most severe where the lava meets the ocean. Here, the unprepared encounter dense, acidic fumes, scorching heat from the flows, sharp and rugged surfaces, steam explosions that can shower large areas along the coast with hot spatter, cinder, or incandescent blocks, and the swift killer, the bench collapse.

As lava enters the ocean, much of it is fragmented into the fine, black sand that made Kaimu famous. The flows then cover the sand and continue to build new land. However, sand is a poor foundation for the new land and occasionally slides into the ocean, carrying its load of new lava flows and the unwary visitors who venture onto them. In the past several weeks, a lava bench measuring about 200 by 800 feet slid away. These slides occur with little warning, so our staff rarely ventures out onto these new benches.

Before you decide to go to the edge, ask yourself the question, "How fast can I run across 200 feet of rough lava?" If the answer is more than 5 seconds, you are literally gambling with your life. Several years ago, one visitor to the Park who ventured beyond the area closure signs onto a bench discovered that he could not run fast enough; he was killed as the bench slid away.

When benches slide away into the sea, they produce small, local tsunami that wash back onto the land. These tsunami can carry large rocks up onto the bench, or wash people off the bench and out to sea. Because seawater is heated where lava enters the sea, boiling water from the tsunami constitutes an additional hazard. Several Park visitors who ventured beyond the area closure signs have been seriously burned by scalding hot water that enveloped them from a rogue wave. Had they been there during a bench collapse and ensuing tsunami, they, too, would probably have been killed.

The newest and least stable lava bench along the ocean is not always easy to identify because numerous surface flows may have completely buried the old sea cliff. This does not mean it is safer, only that the added weight of lava on top of the sand is greater and that a long time may have elapsed since a slide has occurred. If anything, such conditions increase the likelihood of a slide in the area.

Farther inland, other hazards lie in wait for the unwary. The most dangerous of these is the methane explosion. Methane is produced in large quantities as the flows cover vegetation. This gas can travel in tubes underground for several hundred feet and is eventually ignited by the flows or by fires set by the flows. The methane not only bums, but it also explodes violently. These explosions can be heard more than a mile away as dull, booming sounds. In such explosions, small craters are created when rocks -- and any people standing on those rocks -- are blown into the air. We who monitor the eruption walk on top of the youngest (sometimes still hot) flows, rather than near the margins of flows adjacent to burning vegetation.

We urge all visitors to be patient and wait until the lava flows are safely accessible. The hazards are varied and can be deadly. When the flows can again be viewed safely, we will inform the National Park Service, who, in turn, will provide safe access to the flows for all visitors.