When
I gave a presentation on natural phenomena and family history last year, I was
asked about whether and when we might experience a major volcanic eruption in
Yellowstone. I said I did not expect such a thing for thousands of years yet
and that we should not worry too much about it.
Coincidentally,
shortly afterward National Geographic
magazine featured the region in its May 2016 issue. The magazine had previously
reported on the volcanic eruptions there in August 2009 (When Yellowstone Explodes). In that issue was a map showing what
areas had been impacted by major eruptions during the last 18 million years.
Great outpourings of lava have occurred at intervals of about 2.2 million
years. The deposits are spread along a line extending 430 miles from northern
Nevada to northwest Wyoming which resulted as the North American plate moved
across a hot spot in the Earth’s mantle. The last eruption occurred about 640
thousand years ago suggesting it will be a very long time before we have to
worry about another event.
 |
Map
of volcanic fields resulting from major eruptions of the Yellowstone
supervolcano over the past 18 million years published by National Geographic in
August 2009
Eruptions
of this supervolcano have never affected human populations but the fear
remains. Occasionally articles will appear in magazines and scientific reports
about the NEXT BIG ONE and whether it will happen much sooner that what the
timing of previous episodes may indicate. A story appeared on the National Geographic website last week by
Victoria Jaggard titled Yellowstone
Supervolcano May Rumble to Life Faster Than Thought.
I
remain convinced that we do not have to be concerned about being wiped out by a
Yellowstone eruption, at least within the next several hundred generations. But
eventually it will happen.
With
our lifetimes we have witnessed the effects of volcanoes spreading death and
destruction in many part of the world. The most affected regions are those on
the edges of tectonic plates such as the Ring of Fire around the Pacific Ocean.
Historically
there are many examples of ash and lava spreading over areas inhabited by
humans. Most resulted in the deaths of scores of people and, for that reason,
are worth reviewing in any family history study. Researchers may find that some
of their ancestors were affected by the spread of volcanic ash and gas:
sickness of themselves or their livestock; damage to environment and its impact
on agriculture; and even death.
The
devastation in Pompeii certainly would have ended many family lines when the
mountain exploded in AD 79. We know communities nearby volcanoes can be quickly
buried by lava and ash and their residents killed or forced to evacuate.
Deleterious effects of ash and poisonous gases thrown into the atmosphere can
be measured around the globe for many years after a major eruption.
Among
the many that resulted in major death tolls are:
Year
|
Volcano
|
Location
|
Death Toll
|
1815
|
Mount
Tambora
|
Indonesia
|
100,000
|
1883
|
Krakatau
|
Indonesia
|
36,000
|
1902
|
Mount
Pelée
|
Martinique
|
30,000
|
1985
|
Nevado
del Ruiz
|
Columbia
|
23,000
|
1600
|
Huaynaputina
|
Peru
|
15,000
|
1792
|
Mount
Unzen
|
Japan
|
15,000
|
1783
|
Laki
|
Iceland
|
10,000
|
Laki, Iceland
A
major eruption in Iceland in June of 1783 resulted in millions of tons of ash
and gas being ejected into the lower troposphere. Over several months it spread
across Europe and into the Middle East. It has been estimated that over 23,000
people perished as a result of the toxic plume.
Tambora
The
last major eruption in Tambora in April 1815, its early explosions heard over
800 miles away. More than 90,000 people died in Indonesia alone. Over 24 cubic
miles of gas and particulate were pushed into the stratosphere which then,
within weeks, spread around the world. The Earth was blanketed by a shadowy,
poisonous veil which caused havoc with climatic conditions: sunlight was
reflected back into space; temperatures at the surface were cooled, and weather
patterns were completely disrupted. The year following the Tambora eruption has
been called the Year Without Summer
because in most parts of the world in 1815, conditions were wet, cold and just
plain miserable!
Krakatau
The
paroxysmal eruption of Krakatau in Indonesia in August 1883 also spread dust
and gas around the world. The initial blast was heard more than 2,000 miles
away in Australia. A tsunami, almost 150 feet in places rolled over coastlines
around the Pacific Ocean. Similar climatic disruption occurred as was caused by
the Tambora event. In this case, reports were transmitted around the world
almost simultaneously due to the improvements in broadcast technologies. Due to
its proximity in time to today, this event has been more studied than any other
volcanic event and provides a significant example of what can – and probably
did – happen when such natural phenomena occur.
 |
Lithograph:
The eruption of Krakatoa, and subsequent
phenomena. Report of the Krakatoa Committee of the Royal Society (London,
Trubner & Co., 1888)
Mount Pelée
More
recently the top of Mount Pelée was blasted apart in May 1902. A resulting pyroclastic
avalanche rolled down over the city of Saint Pierre killing virtually everyone
in its path. Residents failed to heed the warnings of the eruption which began
three weeks before the major event, assuming that only lava would be produced
as had been the case previously. Many even stayed to observe the beginnings of
the eruption, much as they do around other volcanoes around the world such as
in Hawaii. In the end people failed to take seriously the power of a volcano
and paid with their lives.
In
terms of family history studies, volcanic events may have played an important
role in changing the lives of many families in the past, in ways similar to
that of the four outlined here. Such life-altering effects may have resulted
from eruptions which occurred on the other side of world; a knowledge of
natural history might be useful.
