BY ON 4/14/17 AT 6:19 AM
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, by volcanic activity, with many of these deaths attributed to secondary hazards associated with the main eruption. Starvation killed 92,000 following the 1815 in
, for example, and a
volcanic tsunami killed 36,000 following the . 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.
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.
Known for its , that destroyed the towns of
Pompeii and Herculaneum, Vesuvius is still a significant hazard given
that it overshadows the city of
and its surrounds, that are home to over 3 million people. Naples
It is also known for a particularly intense form of eruption. (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
Republic of Congo
This 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.
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.
, is just 70km southwest of the one of the largest cities in the world:
, home to 20m
people. Popo is regularly active and its most recent bout of activity in 2016
sent a plume of ash to an altitude of five kilometers. 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 , can be extremely deadly, as exemplified by the when around 26,000 people were killed in the town of
by a lahar with a volcanic source that was 60km away. 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.
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
atomic bombs. The eruption
destroyed the volcanic island completely, but within 50 years, a new island had
appeared in its place. Hiroshima
The new island is named (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.
Few have heard of this volcano in a remote part of
Asia—. 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 , 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
Given such a geo-politically sensitive location, the effects of any volcanic
activity here would likely be very hard to manage. North Korea