Part 2 of  PhD student Geoff Hellman’s in depth study of the eruption of the Laki volcano and the effects it had worldwide. He has kindly allowed us to publish some of his writing.

Annus Mirabilis

Earthquakes, in Italy and elsewhere

Southern Italy and Sicily showing the Calabrian Earthquakes (Wikipedia)

The series of earthquakes which struck Calabria and Messina between the 5^th of February and the 28^th of March 1783 was the most severe to strike Italy since the Sicily earthquake of 11^th of January 1693, which killed some 60,000 people. During a period of nearly two months of activity a series of five quakes in Sicily and the Calabrian region of southern Italy, killed an estimated 35,000 to 50,000 people and devastated many towns and villages.

Over 1,500 of these deaths were due to a tsunami which was triggered by the major collapse of Monte Paci into the sea near the town of Scila on 6^th of February. Many of its inhabitants being fearful for their safety thought it safer to spend the night on the beach away from any buildings that might collapse, where they were overwhelmed by the deluge.

Several other earthquakes and tremors of minor importance occurred during mid- summer and December. On 6^th of July there was an earthquake in the regions of the Jura, Franche-Comté, Burgundy and Geneva, minor quakes in Maastricht and Aachen on 8^th of August, and tremors in northern France on 23^rd of December.

Volcanic Eruptions in Europe

Although the Laki eruption is the most famous, the Grimsvôtn eruptions were not the only ones that took place in 1783. Towards the end of February a submarine eruption occurred at Fuglasker, off the Reykjanes Peninsula in the south west of Iceland. This event continued until the summer of that year and formed the shortly lived Island of Nýey (New Island), which vanished soon afterwards.

There was also quite a lot of volcanic activity in Italy. On the 17^th February, it was reported that Etna had erupted, and this was followed within a few days by Stromboli and probably Vulcano, thus adding to the destruction caused by the Calabrian and Sicilian earthquakes. Six months later, on the 18^th August there was a small eruption, of little consequence, on Vesuvius, which began that volcano’s 1783-1794 eruptive sub-cycle.

Volcanic activity of some sort was also reported to have taken place in the early summer at the Gleichberg mountain in Thuringia, Germany, but hard evidence is singularly lacking, and it could all be an elaborate hoax.

The Hot Dry Fog and Blood-Red Sun

The summer of 1783 is best known for the abnormally hot, persistent, sulphurous, dry fog, which was generated by the Laki eruption and which pervaded Europe and much of the northern hemisphere for the second part of the year. Some of the more bizarre contemporary explanations blamed the haze on the Calabrian earthquakes, evaporations from the soil, atmospheric electricity, meteors and the debris from the tail of a comet. However, Professor Kratzenstein of Copenhagen University and the French naturalist, M. Mourgue de Montredon correctly identified its origin as being due to a volcanic eruption in Iceland.

Locations and timing of the first appearance of the Laki haze in June 1783 in the Northern Hemisphere ( Thordarson & Self (2003))

The first appearance of the fog outside Iceland was around the 10^th of June in the Faeroe Islands, Bergen and Trondheim, when there was a fall of volcanic ash and acid rain. There were also reports that ships sailing between Denmark and Iceland experienced an ashfall which coloured their decks and sails black. According to Geikie, there was a fall of ash in Caithness, Scotland, which spoiled the crops, and caused it to be called “the year of the ashie”, and Venice, in Italy, experienced a haze of dust so rich in iron that it was attracted to a magnet. In western and southern Europe, a fine haze was first noticed between the 16^th and 19^th of June and by the 26^th, almost all Europe was shrouded by a thick, evil-smelling, dry fog which made the eyes smart, triggered headaches and caused great distress to those suffering from asthma or similar conditions.

Locations and timing of the first appearance of the Laki haze in June 1783 in Europe (Thordarson & Self (2003))

In the following extract from The Natural History of Selborne, Gilbert White gives a vivid impression of his experience of the fog.

The Natural History of Selborne

Gilbert White, writing in his journal on 7^th of July, said that, “The heat overcomes the grass-mowers & makes them sick”.

“At Sallon the fog sometimes diffused a very disagreeable smell…which some believed to be sulphurous…It was hurtful to the eyes… persons whose lungs were weak, found disagreeable effects from it. The inhabitants of the Champsaur informed me that several people in the neighbourhood had violent pains in the head…”

van Swinden wrote that: “In the afternoon of the 24^th (June) many experienced very troublesome headaches and respiratory difficulties, similar to that which they experienced while the atmosphere around us was filled with the vapour of burned sulphur. Asthmatics experienced a return of asthma.” 

Antonín Kodytek, a teacher in Kunvald, eastern Bohemia, made much of the heat when writing in his journal:

” … in summer there was such a heat that if there were not for the unusual fog which shaded the sun, perhaps everything would have been burnt by the sun’s heat. Because the rising morning sun could not be seen due to the fires and then from six to nine o’clock the sun looked like a red hot iron ball, then from nine to three or four o’clock it shone more intensely, but looked sad, which made the people wonder.”

By the 30^th of June it had reached Moscow, and the following day, the Altai Mountains of central Asia, some 7,000 km. from Iceland.

There are many reports from Europe and further afield describing the fog and the violent storms resulting from it. Benjamin Franklin, the American ambassador to France, writing from Paris in 1784, said:

“…during several of the summer months of the year 1783, when the effect of the sun’s rays to heat the earth in these northern regions should have been greater, there existed a constant fog over all Europe, and great part of North America. This fog was of a permanent nature; it was dry, and the rays of the sun seemed to have little effect towards dissipating it, as they easily do a moist fog, arising from water. They were indeed rendered so faint in passing through it, that when collected in the focus of a burning glass they would scarce kindle brown paper.”

He then goes on to ponder the cause of the fog, being one of the first to suggest that it was volcanic in origin:

“Whether it was adventitious to this earth, and merely a smoke, proceeding from the consumption by fire of some of those great burning balls or globes which we happen to meet with in our rapid course round the fun, and which are sometimes seen to kindle and be destroyed in passing our atmosphere, and whose smoke might be attracted and retained by our earth; or whether it was the vast quantity of smoke, long continuing; to issue during the summer from Hecla in Iceland, and that other volcano which arose out of the sea near that island, which smoke might be spread by various winds, over the northern part of the world, is yet uncertain.”

However, Josepho Toaldo, writing of the fog which arrived in northern Italy on the 18^th of June and lasted for a large part of August, thought that it was caused by the earthquakes in Calabria:

“Abbiamo considerate questa nebbia, ch’era secca ed alta, come un polverio eccitato dale concussion della terra, o come un fumo delle interne fermentazioni, dai venti portato sopra luoghi distanti, come sopradi noi dalla Calabria.”

A report dated 29^th of September, 1783, which appeared in the Gentleman’s Magazine shows that the thick fog had not only reached, but was still prevalent along the Mediterranean coast of Africa:

“By the late mails from Africa it appears that the fogs in summer were thicker and more suffocating all along their coasts than with us in England, and that in the Archipelago, and along the Mediterranean sea, they were so thick as to render the communication dangerous.”

The reason of course, for the sun’s blood-red colour was that it was being viewed through the extremely dense fog of volcanic pollution.

As if the fog were not enough, it was frequently interrupted by violent storms, accompanied by intense thunder and lightning, which in many cases caused loss of life to both people and livestock, as well as considerable damage to crops and property.

Next week: Violent Storms and Great Balls of Fire

Related Stories: The Laki Eruption of 1783 by Geoff Hellman

Robert Burns and the Laki Volcano of 1783