Tuesday 17 October 2017

Natural Disasters and Family Misfortunes 8: Volcanoes

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:
Death Toll
Mount Tambora
Mount Pelée
Nevado del Ruiz
Mount Unzen

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.


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!


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.