protecting the publicís health
America and the Caribbean is a high-risk region for volcanoes. In the
twentieth century, 76 percent of the deaths caused worldwide by volcanic
eruptions were in this region. In the last 10 years, nearly half of the
strongest eruptions in the world occurred in Latin America and the Caribbean.
Each volcano entails
specific risks. In addition, each risk can have a different impact depending
on the specific circumstances of the eruption, calling upon different
public health preparedness activities. The following are some of the most
common hazards resulting from volcanic activity.
- Lava. Contrary
to what most people believe, lava fronts advance at a very slow pace,
and do not constitute a significant hazard during volcanic activity.
- Rock and debris.
Although an active volcano may spew rocks and other debris over considerable
distances, the likelihood of this causing injuries or fatalities is
- Ash. The
fall of volcanic ash may constitute a direct health hazard. During a
volcanic eruption, a thick layer of ash may fall. It is a myth perpetuated
by the media, however, that ash fall is a major health hazard for otherwise
healthy individuals. In fact, there is very little serious danger posed
by volcanic ash. Although it may affect those with ongoing respiratory
illnesses, there is currently no evidence of excessive mortality due
to cardiopulmonary problems caused by inhaling ash. Ash falls, however,
can pose several other challenges for communities: Ash falls can fill
the air with a smoke-like mist that will significantly reduce visibility.
Impaired vision will increase the numbers of traffic and other accidents.
Roads can be slippery when covered with ash, and windshields will be
smeared with a thin deposit of wet ash.
of water supplies. Springs and rivers near volcanoes can become
contaminated with ash or acid rain, affecting the quality of the water
and even rendering it undrinkable. Strict monitoring by health authorities
In a very small number of cases, relatively heavy gases can lead to
deaths due to air pollution. Fortunately, in the case of most eruptions,
the winds blowing over the crater quickly scatter these gases.
When a volcano is under water, its eruption can cause the extremely
high waves known as tsunamis. Risk is low, but the consequences can
be so devastating that attention must be paid to the likelihood of this
flows. The avalanches of hot ash, pumice, rock fragments and volcanic
gas that rush down the sides of a volcanoknown as pyroclastic
flowsdo pose major risks. In Latin America and the Caribbean,
nearly 60 percent of all deaths due to eruptions are caused by pyroclastic
flows. They are a mixture of solids and gases that will destroy everything
in their path. There is no chance for survival in the direct path of
a pyroclastic flow. Evacuation is the only solution.
- Mudflows and
debris flows (lahars). Mudflows and debris flows from the slopes
of a volcano, also known by the Indonesian name lahars,
account for 42% of all fatalities caused by volcanic eruptions around
the world. Under the intense heat of the eruption, mountaintop icecaps
melt, or crater lakes overflow, and the resultant avalanche of mud and
debris leaves little time for evacuation before entire cities are razed
to the ground.
Planning for Volcanic Emergencies
When planning for
volcanic emergencies, it is necessary to view the various risks in perspective
and concentrate only on those that truly pose a serious threat to public
After compiling all
the necessary information on at-risk areas, existing vulnerabilities and
the likelihood of the various phenomena, plans should be produced to respond
to an eruption and its potential consequences.
During and after an
eruption, access roads are frequently blocked, basic services are interrupted,
and there is often a lack of human and physical resources for responding
to the emergency.
The best way to prevent
catastrophic events is by not allowing human settlements too near volcanoes.
When the settlements are already there and the volcano shows signs of
becoming active, the best response is the early evacuation of the population
to places away from the areas at risk.
A health-sector contingency
plan for volcanic emergencies must contemplate the following measures:
- Medical treatment.
Planning in this area includes search and rescue mechanisms, the
care of massive number of patients, the careful monitoring of air and
water quality, an assessment of the impact on public health and sanitary
needs, epidemiological surveillance and provision for the outbreak of
mental health problems.
- Supply management.
The emergency supplies and equipment needed to respond to a volcanic
emergency must be at hand well before the onset of the event. Unless
other types of disasters, emergency supplies must include light dust
masks and eye protection against ash falls.
- Training and
information management. Appropriate public information is essential
in the event of a volcanic eruption, particularly when mass evacuation
is needed. All community members should be aware of protection measures,
including specific information aimed at people with respiratory diseases.
The information should focus not only on the direct effects of the eruption,
but also on indirect effects such as water contamination. The plan must
also include ongoing training for health sector and relief and rescue
personnel, so that they are aware of all the points mentioned above.
Finally, it should
be noted that the plan must be tested through drills and participatory
discussions, in order to verify that health personnel are properly prepared
and feel comfortable with all the necessary steps. And the plan should
be updated periodically to take into account changes in resources and
From the guide
Volcanoes: Protecting the Publics Health, Pan American Health
Organization (PAHO), 2002.