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).