What are my risks?
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.).
| Island |
Volcano
|
Age (million
years) |
| Kahoolawe |
Kahoolawe
|
1.0 |
| Lanai |
Lanai |
0.81-1.5
|
| Molokai
|
East Molokai
|
1.3-1.75 |
| |
West Molokai
|
1.5-1.8
|
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).