Page 103 - Volcano and Geothermal Tourism

80 The Americas

Hydrogen chloride/hydrochloric acid from tephra have been documented on Mt Semeru
Another volcanic gas posing potential health in Indonesia and on Galeras volcano in Colombia
hazards for tourists is chlorine. Chlorine gas is (Baxter and Gresham, 1993; Thouret et al, 2007).
emitted from volcanoes in the form of hydrogen In the incident on Galeras, three tourists and six
chloride and hydrochloric acid (HCl) (USGS, volcanologists were killed while visiting the caldera
2009a). Exposure to HCl can irritate eyes, mucous of the volcano when a small eruption occurred
membranes and the skin. It can further induce without warning. The victims were pelted with
coughing, burning of the throat and a choking volcanic bombs >1m in diameter for approximately
sensation (Stephenson et al, 1991). Exposure to 15 minutes and sustained devastating head and
concentrations over 35ppm will irritate the nose, chest injuries along with other impact injuries
throat and larynx after short exposure. However, (Baxter and Gresham, 1993). Volcanic bombs from
exposure to concentrations >100ppm can result in this small eruption were found 1km beyond the
acute laryngeal spasm or pulmonary edema rim of the caldera (Baxter and Gresham, 1993).
(Stephenson et al, 1991). Recently it has been Aside from impact injuries, tephra can cause
noted that when active lava in coastal regions health problems through inhalation and contact
flows into seawater, the results produce a dense with the skin and eyes. For example, newly fallen
HCl mist that is referred to as volcanic laze volcanic ash can have acid coatings and be very
(Heggie et al, 2009). This process occurs when the abrasive to the skin (Hansell et al, 2006). If inhaled,
lava entering the ocean rapidly boils, vaporizes fine ash particles can cause respiratory irritation
seawater, and produces a white plume containing and chest discomfort as well as corneal abrasions
a mixture of HCl and concentrated seawater that and conjunctivitis.
is a brine with a salinity about 2.3 times that of Moreover, acute short-term conditions such
seawater and a pH of 1.5–2.0 (Heggie et al, 2009). as nasal irritation and dry coughing can occur.
Table 5.2 displays the seawater chloride reactions For tourists with asthma or other respiratory
that produce HCl. Exposure to this dense volcanic conditions, ash can cause the lining of the airways
laze is known to have caused the death of tourists to produce more secretions which can easily
in Hawai‘i (Heggie et al, 2009). result in more severe concerns. The severity of
any such incident will naturally be influenced by
duration of exposure and the presence of
Tephra and ash crystalline silica and any volcanic gases mixed
Tephra is a general term describing fragments of with the ash. Long-term exposure to crystalline
volcanic rock and lava that are blasted into the air silica can result in silicosis and conditions such as
by explosions or carried upward by hot gases and chronic obstructive pulmonary disease (COPD)
lava fountains (USGS Volcano Hazards Program, (Hansell et al, 2006).
2009a). Tephra fragments are classified by size with Heavy or frequent amounts of volcanic ash
fragments <2mm in diameter labelled as ash. pose an additional threat to the structural
Tephra fragments that are between 2 and 64mm in capabilities of tourist facilities such as hotels and
diameter are called volcanic cinders or lapilli, and ski lodges. Such conditions from volcanoes like
when >64mm in diameter are called volcanic Japan’s Mt Usu have had considerable impact on
bombs or volcanic blocks. Tourist fatalities resulting the hot-spring resort town of Toyako-Onsen on
the island of Hokkaido (Hirose, 1982). Moreover,
another major concern about volcanic ash is the
Table 5.2 Seawater chloride reactions that produce HCl threat it poses to aviation and tourist transport
operations. For example, visibility is greatly
MgCl (sea salt) + H O (steam) = MgO (periclase) + 2 HCl (HCl gas)
2 2 reduced during ash falls, and roads, highways and
2 NaCl (sea salt) + H O (steam) = Na O (sodium oxide) + 2 HCl airport runways become slippery or impassable
2 2
when ground ash becomes wet.
CaCl (sea salt) + H O (steam) = CaO (lime) + 2 HCL (HCl gas)
2 2 Moreover, volcanic ash particles can remain in
Source: USGS Volcano Hazards Program, 2009 the atmosphere for years and be spread globally by

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