WHAT ARE VOLCANOES?
The term VOLCANO signifies a mountain or hill with
an opening or vent from which gaseous liquid or solid materials
from the earth's interior are ejected. The term is also used
for mountains, hills, or craters formed by the accumulation or
removal of materials during past volcanic events even if no active
vent is presently existing.
WHAT IS A VOLCANIC ERUPTION?
This is the process wherein volcanic materials such as lava,
fragmented rocks or gases are emitted or ejected through a crater,
vent or fissure on to the earth's surface to form new deposits.
WHERE ARE VOLCANOES IN THE CARIBBEAN?
The Caribbean has several volcanoes distributed all over the
Region. Those that been recorded as having erupted are classified
as active volcanoes. The others are classified as inactive.
Presently, the most active is the Soufriere
Hills Volcano in Montserrat.
EXPECTED HAZARDS
There are several processes that occur on the slopes
of the volcano that pose hazards to man and his environment.
Most of the hazards are directly caused by volcanic eruptions.
-
BLASTED
PROJECTILES: Large projectiles can damage buildings;
if these are hot they can start fires.
-
MUD FLOWS (lahars): Frequently accompany volcanic
eruptions and can be lethal. Lakes can mix with volcanic
rock and debris to form a near-solid flow which engulfs
all in its path.
-
PYROCLASTIC
FLOWS: Mixtures of hot gases, ash, fine pumice and rocks;
danger lies in the density and temperature of the ash and
rock fragments. Pyroclastic flows can move at very high
speeds, possibly over 100 km/h. Hazards include body surface
burns, inhalation injuries and asphyxia.
-
GASEES:
These may be asphyxiants which are concentrated near the
volcanic crater or fissure or respiratory irritants which
are more dispersed and can be harmful at lower concentrations.
-
LAVA
FLOWS: These are flows of extremely hot molten rocks
extruded by the volcano. The viscosity and high temperature
make these flows very dangerous and they are capable of
destroying all in their path.
-
LOCAL
EARTHQUAKES: Possible loss of human life and property.
-
TSUNAMIS:
Tsunami is Japanese for "tidal wave", the seismic
wave that can hurtle across oceans at up to 600 miles per
hour (800 km/hour). Occurrence is unpredictable and
can destroy coastlines.
LIKELY IMPACT
The effects that can be expected from these are the damage
and injury or death by impact, incineration, burial and bulldozing.
Another hazard that is also directly related to volcanic eruption
is the fall of volcanic materials ejected from the crater.
EMERGENCY ACTION
Volcanic eruptions are preceded by signs, some of which are
not detected by instruments, nor observed by Volcanologist.
The following are some points that should be taken into account
to effectively respond to a volcanic eruption:
Community Preparation
BEFORE THE ERUPTION
-
Demarkation
and evacuation of areas of risk.
-
Formulation
of and familiarization with search and rescue plans.
-
Preparation
of hospital emergency plans to cope with large influx
of patients with burns, lung damage and trauma.
-
Identification
of facilities to collect and analyse ash for toxic elements
and drinking water quality.
-
Facilities
and equipment for monitoring air.
-
Plans for
procurement of emergency supplies.
- Report any and all unusual physical changes around volcanoes
to the Seismic Research Unit, e.g. the drying up of vegetation,
rumbling sounds, earthquakes, landslides and other possible
abnormalities.
DURING THE ERUPTION
-
Pay attention
to Warnings, which would include evacuation notices and
escape from area as quickly as possible.
-
Listen to
the radio for information and advice.
-
Find shelter,
but NOT in a building with low-pitched or flat roof, if
heavy ash is falling.
-
Avoid basements
and closed spaces where gases may accumulate.
-
Wear protective
clothing over head and body if you have to move in an
ash shower.
-
Breathe through
a handkerchief.
-
Always carry
a flashlight, even during the daytime.
MITIGATION MEASURES
-
Establish permanent
danger zones (4 to 6 km radius circle) around the summit
of active volcanoes.
-
Educate population
about Volcano risks.
-
Improve Warning
and Evacuation Systems.
-
Identify resources
needed for emergency response.
VOLCANOES IN THE CARIBBEAN
On 25 June 1997, pyroclastic flows from an eruption resulted
in the first deaths directly caused by the volcano. Ten (10)
people were confirmed dead while another 10 were missing and
presumed dead.
On 17 July 1995, the Soufriere Hills Volcano in Montserrat began
erupting. The severity of eruptions progressively increased
and two years later, the volcano had made most of the island
uninhabitable. It also caused severe disruption tof the economic
and social life of the island, resulting in more than half the
population leaving.
On 8th May 1902, Mt Pelée, in Martinique erupted. A glowing
avalanche (pyroclastic flow) from the eruption destroyed the
town of St Pierre and its 28,000 inhabitants. Only one person,
a prisoner, survived.
In 1902, the Soufriere volcano in St Vincent erupted.
The eruption began on 6th May, 1902 and continued until 30th
March, 1903. 1,565 people were killed and extensive damage was
done to agriculture in the areas around the volcano. The Soufriere
volcano erupted again in 1979.Between 2001,Kick'em Jenny also
showed signs of activity which placed the suronding islands
on yellow alert.
The Caribbean has
many volcanoes and has suffered the consequences of volcanic
eruption on several occasions.
Soufriere
Volcanos
While Montserrat's Soufriere Hills Volcano is the only one in
the region that is currently erupting, the volcano known to
have erupted most frequently this century is Kick 'em Jenny,
an undersea volcano located about 8 km north of Grenada. Kick
'em Jenny is known to have erupted at least eleven (11) times
since it was first identified in 1939
Additional Sources of Information
Montserrat
Volcano Home Page
Seismic Research
Unit (University of the West Indies)
Volcanoes
