There is nothing to suggest that any
ancient civilization would have been able to predict volcanic
eruptions thousands of years hence.
Therefore the inclusion of this
section is due to super-volcanoes fitting the global cataclysm
category, and because we shouldn't rule out any possibilities, no
matter how remote. Also, keep in mind that
a pole shift type event
might be predictable, and a pole shift could be the trigger for an
eruption - so they don't necessarily happen in their own due course.
In general, if a global cataclysm triggers volcanic eruptions,
active volcanoes presently exist on every continent except for
But the type of volcano that can single-handedly harm the
entire planet in a substantial manner is a super volcano.
What is a Supervolcano?
A supervolcano is an arbitrary definition for volcanoes that can
have the largest of eruptions. It is such a recent term, the
spelling of the word is not yet set in concrete, but we'll use the
spelling most commonly used.
While there is no precise measurement
used to qualify a volcano as "super", the word is used to describe
volcano that can threaten global civilization. A supervolcano will
either wipe out all of humankind, or make a very good attempt to do
It is the only local, natural event that has such power, and ranks
comets and asteroids as a force of nature we should fear.
Supervolcanoes tend to be active over millions of years. They erupt
less frequently than other volcanoes, but when they do erupt, they
are substantially more intense.
They are rare enough to be missing
from modern history, and we only know they have ever occurred due to
geological studies of the clues they have left for us.
Supervolcanoes of the Past
These are the largest supereruptions we are aware of - they all have
Volcanic Explosivity Index of 8 (VEI-8) which means they have
thrown out at least 1,000 km³ Dense Rock Equivalent of ejecta.
ejecta is the most important criteria in terms of risk to
the survival of our species.
Local disasters will not affect our
continued existence, but this level of ash in the atmosphere will
create immense difficulties for the entire planet.
26,500 years ago - Lake Taupo, NZ - 1,170 km³
74,000 years ago - Lake Toba, Sumatra - 2,800 km³
254,000 years ago - Whakamaru, NZ - 1,200-2,000 km³
640,000 years ago - Yellowstone, USA - 1,000 km³
2.1 million years ago - Yellowstone, USA - 2,500 km³
2.5 million years ago - Cerro Galan, Argentina - 1,050 km³
4 million years ago - Atana Ignimbrite, Chile - 2,500 km³
4.5 million years ago - Yellowstone, USA - 1,800 km³
6.6 million years ago - Yellowstone, USA - 1,500 km³
27.8 million years ago - La Garita Caldera, USA - 5,000 km³
29.5 million years ago - Sam Ignimbrite, Yemen - 5,550 km³
As an indication of how massive these supereruptions were, Mt St
Helens had just 1.2 km³ of ejecta, and Krakatoa had 25km³.
While it might be possible to discern eruption patterns for
individual volcanoes, collectively it becomes much more random.
Hopefully scientists will be able to forewarn us of the next one to
How Bad Can a Supervolcano Be?
supereruption of Toba caused temperatures to drop globally by
between 3 and 9 degrees Fahrenheit, as much as 18 degrees in some
places, killed 80-90% of humans and destroyed as much as
three-quarters of all vegetation in the Northern Hemisphere. (1)
Substantial amounts of ash were distributed across southern Asia. In
India, the ash was typically six inches thick, and at one site it
reached an extraordinary depth of twenty feet.(2)
Tephra is the fragmental material created by a volcanic eruption.
Different types of tephra are determined by size - anything larger
than 2.5 centimeters is called a "bomb", and ash is the smallest.
Volcanic ash is quite different to the ash you get from burning
something. Because it is a fragment of glass or rock, it has sharp
edges - if you breathe it in, you will damage your lungs. These tiny
pieces will combine with the moisture in your lungs and form a type
eruption of Mount Tambora in 1815 was minor compared to a supereruption, but serves as an example of the types of problems we
could face. It ejected an estimated 36 cubic miles of ash and
pumice, rising as much as 30 miles into the stratosphere. This cloud
drifted around the world, visually affecting the atmosphere above
both Europe and the USA.
Many places suffered their worst winter on
record. The winter at Yale University, in Connecticut USA, was 7°F
below average. In Europe, food shortages were commonplace. Riots
broke out, and armed groups looted farms. Ireland was worst hit,
where the famine was believe to cause the spread of typhus,
infecting 1.5 million people and killing 65,000. It was known as the
Year Without Summer.
In the last 600 years, only one year has been
colder - 1601, following the eruption of a Peruvian volcano.
Krakatoa eruption of 1883 caused a series of tsunamis, up
to 100 feet in height, killing tens of thousands of people. The
final explosion was deafening, and was heard 3,000 miles away.
Research into some likely large eruptions from 6th century (El Chichon) and 13th century (Proto Krakatoa) suggest that they may
have also caused famines, in each case leading to a widespread
plague outbreak, and possibly, in the case of the former, causing
the Dark Ages.
Chlorine gases emitted can damage the ozone layer.
On top of the
damage we have already inflicted via
CFCs, the eruption of a supervolcano could deplete the ozone layer to such an extent that it
becomes another deadly side-effect. The increase in ultra-violet
radiation would cause skin cancer in humans and damage crops.
The excellent Supervolcano, by Dr John Savino & Marie D. Jones,
includes an in-depth, fictional account of a Long Valley supereruption. Based on current scientific understandings, it is
Here's a brief excerpt:
Within days and weeks of the supereruption, the suspension of air
routes, the inability to bring cargo in and out of the most deeply
affected areas, and the virtual decimation of
the Grain Belt, the
area of our nation responsible for the vast majority of our grain
food sources, all contribute to a growing sense of desperation and
panic among survivors anxious to find food.
It only takes 0.04
inches of ash to close airports, and the wide swath of blanketed ash
would literally shut down every major and minor airport for
thousands of miles across the country.
Because even a small amount of ash can clog an engine, road
transportation is heavily curtailed, and trucks and machines
normally engaged in the moving of supplies from one state to another
find themselves immobilized.
Electrical equipment shorts out, and
wide areas experience power outages and rolling blackouts, rendering
communication via computers and phones obsolete.
The description continues, pointing out the importance of short-wave
They tell of food riots and contaminated water, of violence
and anarchy. Although the USA is the worst hit, the suffering is
global. Greatly decreased food production means mass starvation and
social unrest. It is a truly horrific scenario.
While we can only
hope and pray it does not happen in our lifetime, it will certainly
happen one day. It would be extremely unlikely that mankind can ever
tame even the smallest of volcanoes, so it would appear that a
global catastrophe via a supervolcano is entwined in human destiny.
This map shows the extent of ash fall from the last three eruptions
Candidates for a 2012 Eruption
We know of roughly 50 supervolcanoes that have ever existed, and
most of those are now extinct.
Others are believed to be dormant,
while a few are currently active - listed here under their common
Toba (Sumatra, Indonesia) - supereruption 74,000 years ago, which
was the largest volcanic eruption anywhere on Earth within the last
25 million years. Most humans did not survive this eruption, and in
theory it caused a population bottleneck that may have contributed
to our evolution, or at least our genetic makeup. Toba may have been
active within the last several hundred years
Yellowstone (USA) - last erupted 630,000 years ago. It has been
speculated that the force of a Yellowstone eruption would be the
equivalent of one thousand Hiroshima bombs exploding per second (3)
Long Valley (California, USA) - last erupted 760,000 years ago (600
km³ of ejecta).
Valles Caldera (New Mexico, USA) - last erupted 1.15 million years
ago (600 km³ of ejecta)
Lake Taupo (New Zealand) - supereruption just 26,500 years ago. Has
erupted roughly every thousand years since, with the most recent,
1,800 years ago, being considered the largest in recorded history,
100x larger than Mt St Helens. Fortunately it was not recorded, for
New Zealand was yet to be settled by humans.
Phlegraean Fields (Naples, Italy) - supererupted 39,000 years ago
(500 km³ of ejecta), with other major eruptions since. Could have a
major eruption within decades.
Active - but no evidence they are capable of wiping us out
Kikai Caldera (Japan) - supererupted 6,300 years ago. Still active,
with minor eruptions occurring as recently as 2004
Laacher See (Germany) - potentially still active, erupted 12,900
Mount Tambora (Sumbawa, Indonesia) - last erupted in 1815, killing
at least 71,000 people.
Aira (Japan) - erupted 22,000 years ago (400 km³ of ejecta), but is
still very active. In 1914 an eruption caused the evacuation of
23,000 people. The city of Kagoshima is very close by.
The Yellowstone caldera is an active place, and there are regular
reports that could cause some people to be concerned.
because we have only been monitoring this area for less than a
century, it's impossible to tell whether the current activity is
relatively normal, or if it is unusual and an indicator that
something is up.
A 25 mile section of the caldera rose 5 inches between 1997 and
2003. Prior to this, the whole caldera has risen, fallen, risen,
Between 1923 and 1975 it rose 3-4 feet. Geysers start and
stop mysteriously. In an average year the region has thousands of
earthquakes too small for people to feel underneath them.
Paranoid folk might want to keep their eye on the Yellowstone Webcam
Long Valley is rated by the U.S. Geological Survey as a bigger risk
than Yellowstone. Magma is bubbling beneath the surface, and strong
earthquakes are not uncommon - in 1980 it had four which measured 6
on the Richter Scale.
Paoha Island in the nearby Mono Lake was
created from an eruption just 350 years ago.
This caldera is also showing signs of unrest. Containing a large
portion of the city of Naples, a supereruption similar to the one
39,000 years ago would devastate Europe. Since the late 60s the
caldera has risen by 3 meters.
Even more worrying, scientists are
preparing to drill into the volcano, an act that some experts
consider irresponsible, and could result in an eruption.
In early 2010 the Icelandic volcano
Eyjafjallajokull caused weeks of
travel chaos, due to airlines not willing to risk their engines by
flying jets in zones that could be stricken with ash.
In the greater
scheme of things this is a minor volcano, yet it still manages to
grind local air travel to a halt. A supervolcanic eruption would
render us completely useless...
Government to the Rescue?
Two years prior to the Mt St Helens eruption of 1980, scientists
predicted that an eruption would occur within 22 years.
such information be made public about an imminent Yellowstone
eruption? For example, if a study predicted an eruption in the next
10 years, the economic upheaval created by half of America
relocating could be too much to bear.
Leaders might choose to ignore
the possibility and cross their fingers. Like they (unfortunately)
did with New Orleans.
Plenty of conspiracy theorists have discussed
the possibility of governmental secrecy (at the
Above Top Secret
forum, the Yellowstone topic has over 600 pages of posts), but of
course proof is lacking otherwise it would be fact, not theory.
Where is Safe?
The relative lack of volcanoes make Australia and southern Africa
the places to be...
Having said that, Australia may not have any active volcanoes, but
it did, and it will. The most recent eruptions occurred in South
Australia (5,000 years ago), Victoria (10,000 years ago) and
Queensland (13,000 years ago).
For millions of years the level of
activity in Australia has been decreasing, but small eruptions are
still likely in the future. See
The Volcanic Earth by Lin Sutherland
for details and maps of Australian volcanoes. It also includes
future scenarios, and predicts that eruptions that could affect us
would be small, with the main hazards being lava flow and bushfires.
Australian eruptions would be a minor inconvenience compared to the
climatic disturbances for Australia coming from supervolcanic
Some useful, official sites, for monitoring Yellowstone:
Supervolcano, by Dr John Savino & Marie D. Jones p37
(2) Supervolcano, by Dr John Savino & Marie D. Jones p123
(3) Supervolcano, by Dr John Savino & Marie D. Jones p37