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What
are my risks?
Big Island's Active Volcanoes
Hawaii
County residents are at risk from active volcanoes - lava
flows and airborne fragments, explosive eruptions, volcanic
gases, ground cracks and settling, earthquakes,
and tsunami.
Currently,
Hawaii County has 4 volcanoes classified as active:
- Kilauea,
actively erupting since 1983;
- Mauna
Loa, which last erupted in 1984 and is building
for a new eruption in the next few years; and
- Loihi,
which erupted in 1996.
- Hualalai,
which last erupted in 1801, is thought to erupt again
within the next 100 years.
Lava
Flow Hazard Zones
Lava
flows are the volcano hazard most likely to seriously
threaten people and property on the Island of Hawai`i.
The U.S. Geological Survey (USGS) prepares and periodically
revises maps of lava-flow hazard zones for the island.
These zones are based on the locations of probable eruption
sites, likely paths of lava flows, and how frequently
lava has covered an area in the geologic past.
The
island of Hawaii is divided into zones according to the
degree of hazard from lava flows. Zone 1 is the area of
the greatest hazard, Zone 9 of the least. To read more
about a particular volcano or zone, click
here.
Vog
and Laze Hazards for the Island of Hawaii
Besides
lava, volcanoes spew noxious plumes of acidic gases. The
resulting vog and laze effect many communities on Hawaii.
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).
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