BY ON 4/14/17
AT 6:19 AM
An eruption of Mount Etna recently caught out some BBC
journalists who were filming there. The footage was extraordinary and
highlighted the hazards volcanoes pose to humans and society. 
Since 1600, 278,880 people have been killed by volcanic activity, with many of
these deaths attributed to secondary hazards associated with the main eruption.
Starvation killed 92,000 following the 1815 Tambora eruption in Indonesia
Since the 1980s, deaths related to volcanic eruptions have been
rather limited, but this is not entirely a result of increased preparedness or
investment in hazard management—it is significantly a matter of chance.
Research shows that
volcanic activity has shown no let up since the turn of the 21st century—it
just hasn’t been around population centers. Indeed, there remain a number of
volcanoes poised to blow that pose a major threat to life and livelihood.
Vesuvius , Italy
Known for its 79AD eruption,
that destroyed the towns of Pompeii and Herculaneum , Vesuvius is still a significant hazard given
that it overshadows the city of Naples
It is also known for a particularly intense form of eruption. Plinian (after Pliny the Younger who was the
first to describe the 79AD event) eruptions are characterized by the ejection
of a vast column of gas and ash that extends into the stratosphere, far
higher than commercial airliners fly.
Were such an eruption to occur at Vesuvius today, it is likely
that much of the population would already have been evacuated as a precursory
swarm of earthquakes would likely herald its imminent approach. But those who
remained would initially be showered with huge pumice rocks too large to be
kept aloft by the column of gas.
Then, as the volcano began to run out of energy, the column
itself would collapse, causing smaller particles of rock (from fine ash to
small boulders) to fall from the sky and back to Earth at high velocity.
Asphyxiating clouds of gas and pulverized rock—pyroclastic density
currents—would then flood down the slopes of the volcano, annihilating anything
in their path. Such gas-ash features have been known to travel tens of
kilometers and at terrifying speeds, potentially turning modern Naples into a new Pompeii
Nyiragongo, Democratic Republic of Congo
This central African volcano has erupted several times over the
last few decades and while its eruptions aren’t particularly explosive, it
produces a particularly runny—and dangerous—form of lava. Once effused, this
lava can rapidly move down the flanks of the volcano and inundate areas with
little or no warning.
In 2002, the lava
lake at the volcano’s summit was breached, resulting in streams of lava
hurtling toward the nearby city of Goma
Fortunately, warnings had been issued as the volcano’s unrest
has made it the focus of intense research—and over 300,000 people were
evacuated in time. Should such an event occur again, we have to hope that the
authorities are equally prepared, but this is a politically unstable area and
it remains seriously vulnerable.
Popocatepetl , Mexico
“Popo”, as the locals call it,
is just 70km southwest of the one of the largest cities in the world: Mexico City
In recent times, and indeed throughout much of its history, eruptive
events at Popo have consisted of similarly isolated ash plumes. But these
plumes coat the mountain in a thick blanket of ash that, when mixed with water,
can form a dense muddy mixture that has the potential to flow for many
kilometers and at relatively high speeds.
Such phenomena, known as “lahars”, can be extremely deadly, as exemplified by
the Nevado del Ruiz disaster of
1985 when around
26,000 people were killed in the town of Armero ,
Colombia
The Nevado del Ruiz tragedy was the direct result of volcanic
activity melting ice at the volcano’s summit, but a large volume of rainfall or
snowmelt could feasibly generate a similar lahar on Popo. This could flow
down-slope toward nearby settlements with little or no warning.
Krakatoa , Indonesia
Otherwise named Krakatau, Krakatoa’s name is infamous; 36,000
people were killed by the tsunami triggered by its 1886 eruption,
that released more energy than 13,000 Hiroshima
The new island is named Anak Krakatau (Child
of Krakatoa) and since the 1920s, it has been growing in episodic phases,
reaching about 300 meters in height today. New and significant activity
commenced in 2007 and since this time, further episodes of activity were noted
at the volcano, most recently in March 2017.
No one knows for sure whether or not the spectacular growth of
Anak Krakatau means it may one day repeat the catastrophe its “father”
unleashed, but its location between Indonesia’s two most populated islands,
Java and Sumatra, means it poses a grave threat to life.
Changbaishan , China
Few have heard of this volcano in a remote part of Asia —and its last eruption was in 1903. However, its history
tells a rather scarier story. In around 969AD, the volcano produced one of the
largest eruptions of the last 10,000 years, releasing three times more material
than Krakatoa did in 1886.
One of the chief hazards is posed by the massive crater lake at
its peak (with a volume of about nine cubic kilometers). If breached, this lake
could generate lahars that would pose a significant threat to the 100,000
people that live in the vicinity.
In the early 2000s, scientists began monitoring the hitherto
under-monitored volcano, and determined that its activity was increasing,
that its magma chamber dormancy was coming to an end, and that it could pose a
hazard in the following decades.
Further complicating things is the fact that Changbaishan
straddles the border of China
and North Korea
Matthew Blackett is
Senior Lecturer in Physical Geography and Natural Hazards at Coventry University
