What are my risks?

• Eruptions on Maui?!
• Vog and Laze Hazards

Eruptions on Kauai

The Island of Maui was formed from two principle volcanoes: Haleakala and West Maui. Haleakala is about 0.41-0.86 million years old and West Maui is about 1.2-1.6 million years old. They are considered "dormant" volcanoes.

The following table lists general age information for Kahoolawe, Lanai, and Molokai volcanoes (Macdonald, Abbott and Peterson. Volcanoes in the Sea, 2nd Ed.).

Is there a threat of a volcano erupting on Maui again?

Haleakala's long eruptive history and recent activity indicate it will erupt in the future. Though dormant now, about 1790 (quite recent in geologic time) two minor flows at lower elevations along the southwest rift zone of Haleakala reached the sea and altered the southwest coastline of Maui. In addition, numerous eruptions have occurred there in the past 10,000 years.

Several hundred years have passed since Haleakala last erupted. Vulcanologists (people who study volcanoes) attributed this to the constant northwestward movement of the pacific Plate. This movement has shifted Maui a few kilometers from a molten rock reservoir. Thus, eventually, Haleakala will become extinct.

Today, earthquake records indicate internal adjustments are still taking place in the earth's crust. At present, however, no volcanic activity of any form is visible in the crater nor at any other place on the island of Maui. Perhaps Haleakala could erupt again; we just don't know.

Dr. Ken Rubin, Assistant Professor and Dr. Mike Garcia, Professor
Department of Geology and Geophysics
University of Hawaii, Honolulu, HI 96822

Vog and Laze Hazards for Kauai County

Although volcanoes in Maui County are either dormant or (probably) dead, volcanic hazards do affect the county. Volcanoes spew noxious plumes of acidic gases. The resulting vog and laze effect many communities across the county.

When a volcanic erupts, sulfur dioxide within the molten rock is converted to sulfuric acid. The resulting plume is known as vog (volcanic fog). Gases are also produced at the ocean. When the lava enters the ocean, hydochloric acid is produced - called laze (lava haze). Both of these gases can contain particulate matter, such as volcanic glass or trace metals.

Vog and laze are carried by winds across the county. The impacts include:

• obscured views;
• lower agricultural yields for certain crops;
• adverse health effects for people with respiratory or heart conditions; and
• acidified rainwater catchment tanks (which, in turn, produces a secondary hazard of leached lead in local water supplies).