is already well known that volcanic eruptions - even if
they occur on the other side of the world - can have adverse
effects on weather conditions many thousands of miles away.
and although no specific evidence has, as yet, ever been
found in lighthouse records, it is possible that cooler
weather conditions may have had a direct effect on the seamen
and keepers who supplied and maintained the NLB's lights.
Such an event actually happened in the first half of the
1816, the year in which Capt. Taylor took command of the
newly-built "Pharos", has been often referred to as "the
year without a summer". Global cooling (as opposed to
global warming so commonly referred to nowadays) is now
known to be linked with major volcanic eruptions. In April
of 1815 such an occasion occurred with the cataclysmic eruption
of Tambora, a volcano on the island of Sambawa in
Indonesia - the most powerful eruption ever in recorded
Using the Volcanic Explosivity Index as a guide
to compare other eruptions, Tambora (VEI=7) was more violent
than that of Krakatau in 1883 (VEI=6). The eruption there
was heard 2,500 miles (4,000 km) away, and the subsequent
tsunami (or tidal wave), triggered by the eruption, was
said to have killed 36,000 people. To put it in perpective,
Tambora was about 150 more powerful than the eruption in
1981 of Mt St Helens (VEI=5) in the Amercan North-west.
Only four volcanic eruptions in "recent" times (that
is, in the last 10,000 years) have been assigned a VEI of
7. They are:
Tambora, Indonesia (1815)
Baitoushan, China-Korea border, (about 1050)
Kikai, Japan, (about 4350 BC)
Crater Lake, Oregon, USA, (about 4895 BC)
||10's of years
||100's of years
||St. Helens, 1981
||100's of years
||1000's of years
||10,000's of years
||Yellowstone, 2 Ma
Every thousand years or so, a volcano erupts somewhere
on the planet with enough power to significantly alter the
global climate for years afterwards. Prodigious quantities
of dust and sulphur aerosols are ejected into the atmosphere,
preventing the Sun's rays from reaching the ground. Universal
crop failures occur, temperatures drop dramatically, and
living creatures across the globe die off in large numbers.
Such an event occurred in 1815, on the island of Sumbawa
in Indonesia - the explosion of the great Tambora volcano.
Tambora is just one of many volcanoes in the archipelago
of Indonesia. It lies just east of the popular tourist destinations
of Bali and Lombok, and once it was a mammoth peak - over
4000 (over 13,000 feet) metres high. It is believed that
Tambora had been silent for 5000 years before the explosion
occurred1. Then, in 1812, Tambora awoke from
its slumber, when small eruptions of steam and ash began
to emanate from the mountain, accompanied by significant
earth tremors. This activity continued until 5 April 1815,
when the first great eruption occurred, generating
a volcanic column 25km (15½ miles) high. This blast was
heard over 1000 kilometres away. The worst, however, was
yet to come.
Five days later, on 10 April, a number of colossal explosions
occurred, creating columns of volcanic material that stretched
up to 40km (25 miles) into the sky. What goes up
normally comes down, so when these columns collapsed, they
formed pyroclastic flows - earth-hugging clouds of hot ash,
rocks and pumice, that rampaged across the island killing
everyone and everything in their path2. Almost
the entire population of the Tambora province, over 10,000
people, were killed instantly by these flows. In addition,
when these flows reached the sea, tsunamis up to 5m high
were formed, that careered into neighbouring islands across
the locality, killing yet more people in the immediate vicinity
of the volcano.
The lighter ashes and dusts stayed somewhat longer in the
skies, turning day into night for days across an area hundreds
of kilometres from the blast. When this ash fell back to
earth, it blanketed the ground so perfectly that all vegetation
was killed off, subsequently killing as many as 80,000 people
from famine and disease across many islands in the region.
All in all, over 90,000 people died as a direct result
of the eruption3 - the largest death toll from a
volcano in recorded history.
Tambora from the
The longer term effects of Tambora were felt across the
globe. In addition to the large quantities of ash, rocks
and dust ejected by the volcano, over 200 million tonnes
of sulphur dioxide gas were propelled into the stratosphere.
This had the effect of limiting the amount of sunlight that
reached the ground, so that temperatures, particularly across
the Northern Hemisphere, began to fall dramatically4.
Monsoon season was interrupted in India, possibly leading
to a deadly outbreak of cholera that insinuated its way
across the globe. Europe experienced widespread crop failures
just as it was recovering from the effects of the Napoleonic
Wars. Ireland had its first great famine. Devastating floods
hit China. In North America, 1816 is remembered as 'the
year without a summer', when snow fell during June and frost
was still widespread during the month of July.
It is believed that the Tambora eruption occurred when
ocean water, penetrating cracks and fissures, reacted with
magma deep inside in the volcano, causing a massive build
up of pressure to occur. Eventually the pressure became
too much to bear and the mountain literally blew itself
apart. Over 50 cubic kilometres of magma were ejected
in the ensuing blasts, significantly more than any volcanic
explosion since then.
Arising indirectly from the explosion of Tambora came one
of the best known works of horror fiction in modern times.
It happened that the poets, Lord Byron and Percy
Bysshe Shelley were living by Lake Geneva in 1816. As a
result of the bad weather, they spent much time that summer
with their friends and family entertaining indoors. During
one such meeting, Byron proposed that each member present
attempt to write a ghost story. Shelley's wife, Mary, came
up with a novel that is still remembered - Frankenstein.
In this way, the legacy of Tambora persists to the present
1 Tambora itself is believed to be around
50,000 years old.
2 Pyroclastic flows are, by far, the deadliest effect
of volcanoes. They travel at enormous speeds, are filled
with vast quantities of superheated rocks and ash, and will
displace all air, suffocating a person in seconds. Not a
nice way to go.
3 Some estimates put the death toll at 117,000.
4 The large quantities of sulphur aerosols in the
atmosphere were responsible for incredibly beautiful sunsets
across the globe. J.M. Turner rendered some of these sunsets
onto canvas in the autumn of 1815
Due acknowledgement is made to Woodpigeon on the
h2g2 website - - for the information above