Field of Science

Ancient Stories Provided An Early Warning About Potential Seattle Earthquakes

Oral tradition played – and still plays – an important role in many societies. The subjects of these stories range from fantastic fairy tales to myths, tales based on real persons, places or historic events. But interestingly enough, these stories may also represent attempts to record and transfer knowledge of past geological catastrophes as a warning from generation to generation. Read On...

How Volcanic Eruptions Inspired Artists

As diplomat in France, from 1776-1785, Benjamin Franklin noted in 1783 a strange, grey-bluish mist covering the sky above Europe. Franklin speculated that the cloud was some sort of volcanic dust, may transported from the wind from the Katla, famous Icelandic volcano,  to the European mainland. In fact in June 1783 the Laki on Iceland had erupted, one of the largest volcanic eruptions in historic times with worldwide effects on earth´s atmosphere, climate and history. 

But volcanic dust also influenced art and poetry.

A surprisingly colourful sunset inspired Norwegian artist Edvard Munch (1863-1944) to his famous painting “The Scream”. A distorted figure seems to be petrified screaming in pain, the red background reinforces the despair and agony. Munch himself noted:

"I was walking along the road with two friends - then the Sun set - all at once the sky became  blood red - and I felt overcome with melancholy.  I stood still and leaned against the railing,  dead tired - clouds like blood and tongues of  fire hung above the blue-black fjord and the city. My friends went on, and I stood alone, trembling with anxiety. I felt a great, unending scream piercing through nature."

Exceptional sunsets were observed above Oslo and in many other cities worldwide in the years 1885-92. The New York Times reports on November 28, 1883:

"Soon after 5 o’clock the western horizon suddenly flamed into a brilliant scarlet, which crimsoned sky and clouds. People in
the streets were startled at the unwonted sight and gathered in little groups on all the corners to gaze into the west.  Many thought that a great fire was in progress
....People were standing on their steps and gazing from their windows as well as from the streets to wonder at the unusual sight. The clouds gradually deepened to a bloody red hue,  and a sanguinary flush was on the sea…

Fig.1. Sunset seen in London in the year 1883, from SYMONS, G.J. (1888): The Eruption of Krakatoa, and subsequent phenomena.

The red-glowing sunsets were caused by volcanic ash, dispersed in the higher atmospheric layers the fine particles scattered the sunlight especially effective during sunset.

August 1883 the volcanic island of Krakatoa in Indonesia had annihilated itself in a gigantic eruption. Ash, volcanic dust and gases were send in the higher atmospheric layers, high above clouds and rain the particles would stay for years there, inspiring artists and poets, like English poet Alfred, Lord Tennyson (1809-1892):

"Had the fierce ashes of some fiery peak
Been hurl’d so high they ranged about the globe?
For day by day, thro’ many a blood-red eve...
The wrathful sunset glared..."

Munch however was not the first painter to be inspired by the range of sky-colors caused by a volcanic eruption. Famous English landscape painter William S. Turner (1775-1851) was so impressed by the sunsets in the years 1815-16 that he produced an entire series of paintings, showing the changes observed in the sky for almost one year (Turner will also go on painting more volcano-related paintings). 
In April 1815 the Tambora, also on Indonesia, had erupted, the largest volcanic eruptions in modern times. Also here volcanic particles and dust were injected in the stable stratosphere, scattering for years to come the sunlight and painting the sky in wonderful reddish, orange, bluish-violett colors, an inspiring and haunting view.


OLSON, D.; DOESCHER, R. & OLSON, M. (2004): When The Sky Ran Red - The Story Behind The Scream. Sky & Telescope, February: 28-35

This 1783 Volcanic Eruption Changed The Course Of History

The sun fades away, the land sinks into the sea,the bright stars  disappear from the sky,
as smoke and  fire  destroy  the world,
and the flames reach the sky.
The End of the World according to the “Völuspa“, a collection of Icelandic myths compiled in the 13th century.

June 8, 1783 marks the beginning of a volcanic eruption that will change history…

The true treasure of the North

GOLD! GOLD! GOLD! found in the Klondike river in the Yukon territory, Alaska. The news spread like wildfire, fueling the last great gold-rush of the United States in 1896-99.

Also French businessman Loicq de Lobel decided in 1898 to try his luck in the new world. Even if not directly interested in searching for gold, he hoped to make a living by selling equipment to the prospectors. So the family de Lobel, his wife and four children, following the famous Chilkoot Trail ventured into the northern wilderness, first by feet and later by boat. To distract herself from the perils of the voyage, de Loicq´s wife, which name is not recorded, botanized along the way. She collected for the very first time specimens of the endemic lady's-slipper orchid, Astralagus, bearberry, Epilobium, arnica and a blue-flowering bellflower.

 “… everywhere there were nice flowers, at our arrival at Glenora we found lots of flowering plants...”
The de Lobel family lived for a time in the Yukon territory, then moved to the Aleuten Islands, to finally return to France. The Klondike Gold Rush ended as suddenly as it began, only few found great riches and fortune. However the collected plants by the de Lobel became known as “Klondike River Herbarium” and represents still today a unique botanic treasure.


THINARD, F. (2013): Das Herbarium der Entdecker - Humboldt, Darwin & Co. - botanische Forscher und ihre Reisen. Haupt-Verlag: 168

April 18, 1906: San Francisco´s Wicked Ground

O, promised land
O, wicked ground
Build a dream
Tear it down
O, promised land
What a wicked ground
Build a dream
Watch it all fall down
San Andreas Fault

Maybe the first persons to note something unusual in early morning of April 18, 1906 were the sailors on board of the “Wellington“, just entering the bay of San Francisco. The captain reported later that the ship “shivered and shook like a springless wagon on a corduroy road” even if the sea was as “smooth as glass“.
At the shores of Ocean Beach the worker Clarence Judson was swimming in the sea, when he was grabbed by a strong current and sucked into the deep – only with great effort he reached the safe shore.

I tried to run to where my shoes, hat and bathrobe lay, but I guess I must have described all kinds of figures in the sand. I thought I was paralyzed. ...[]... I jumped on my bathrobe to save me.

In Washington Street the police sergeant Jesse Cook observed a terrifying spectacle:

The whole street was undulating. It was as if the waves of the ocean were coming toward me, billowing as they came ...[]...Davis Street split right open in front of me, []… A gaping trench. . . about six feet deep and half full of water. Suddenly ...[]... sprang up on the sidewalk at the southeast corner while the walls of the building I had marked for my asylum began tottering. Before I could get into the shelter of the doorway the walls had actually fallen inward..

George Davidson, professor for Geography, woke up from the tumult coming from the streets. He grabbed his watch on the desk and noted the length of a first quake – 60 seconds – followed by a second – again 20 to 40 seconds long . His observations – 5:12 a.m. in the morning – will later be used to determinate the official time of the great earthquake of San Francisco in 1906. 

So early in the morning, many people were still asleep and killed in their beds, those who escaped gathered in the streets. Despite the earthquake most of the city seemed still intact and surprisingly quiet.

In 1906 San Francisco was already considered a great and ambitious, but also corrupt and infamous, city with more than 400.000 inhabitants; it had experienced an incredible growth since 1848 thanks to the discovery of gold in the rivers of California. Now it was an important harbour to the Pacific Ocean and a modern trade place, many shops sold the newest technologies in film equipment. The earthquake of San Francisco will become the first natural disaster of this magnitude to be so well documented by photographs and film footage (even in colour).
This growth and achievements were however possible only by cheap and fast construction methods and so most buildings in San Francisco were made of wood and not exceptionally stable. San Francisco had burned to the ground six times in the past century and experienced stronger earthquakes in 1865 and 1868, when 30 people were killed. However the modern fire equipment – horse driven and steam powered water pumps – was believed to be capable to fight every fire.
Fig.1.Earthquakey Times“, a caricature by Ed Jump of the October 8, 1865 earthquake in San Francisco. While he was working as a newspaper reporter in San Francisco, Mark Twain experienced the earthquake which he describes in his 1872 book “Roughing It.” – “It was just after noon, on a bright October day. I was coming down Third Street. The only objects in motion anywhere . . . were a man in a buggy behind me, and a [horse-drawn] streetcar wending slowly up the cross street. . . . As I turned the corner, around a frame house, there was a great rattle and jar. . . . Before I could turn and seek the door, there came a terrific shock; the ground seemed to roll under me in waves, interrupted by a violent joggling up and down, and there was a heavy grinding noise as of brick houses rubbing together. I fell up against the frame house and hurt my elbow. . . A third and still severer shock came, and as I reeled about on the pavement trying to keep my footing, I saw a sight! The entire front of a tall fourstory brick building on Third Street sprung outward like a door and fell sprawling across the street, raising a great dust-like volume of smoke! And here came the buggy-overboard went the man, and in less time than I can tell it the vehicle was distributed in small fragments along three hundred yards of street. . . . The streetcar had stopped, the horses were rearing and plunging, the passengers were pouring out at both ends. . . . Every door, of every house, as far as the eye could reach, was vomiting a stream of human beings; and almost before one could execute a wink and begin another, there was a massed multitude of people stretching in endless procession down every street my position commanded. . . . For some days afterward, groups of eyeing and pointing men stood about many a building, looking at long zig-zag cracks that extended from the eaves to the ground…

Police sergeant Jesse Cook was the first person to report a fire in a grocery in Clay Street, some hours later there where already fifty in the entire city. The fire fighters realized horrified that the water pipers in the underground were broken and the hydrants in the city useless. The firestorm rages in the city for three days and will be responsible for 90 percent of the 28.000 destroyed buildings.

The journalist Arnold Genthe is thrilled by the scenery and the devastation caused by the approaching fire, unfortunately he discovers that his camera was damaged during the quake. “I found that my hand cameras had been so damaged by the falling plaster as to be rendered useless. I went to Montgomery Street to the shop of George Kahn, my dealer, and asked him to lend me a camera. “Take anything you want. This place is going to burn up anyway.” I selected the best small camera, a 3A Kodak Special. I stuffed my pockets with films and started out….
He will take some of the most famous photos in history.
Fig.2.Looking Down Sacramento Street, San Francisco, April 18. 1906“, photography by Arnold Genthe.

In Jackson Street the owner of the “Hotaling´s Whiskey” distillery decides to remain and fight the flames . He pays 80 men to sprinkle 5.000 barrels of whisky with water pumped out from the sewer system. Later he will mock all those who claim that the earthquake was send by god by coining a new advertising slogan for his products:

If, as some say, God spanked the town, for being over frisky – why did He burn the churches down an save Hotaling´s Whiskey?

Army troops were soon ordered into the city to help the firefighters and prevent panic and looting. Despite the fact that martial law was never proclaimed, the major authorized policeman and soldiers to shoot looting persons – “Obey orders or get shot” was the grim warning on some improvised signboards.
Guion Dewey, a businessman from Virginia, wandering onto the streets of downtown San Francisco minutes after the quake, experienced the best and worst of human behaviour, as he later reported in a letter to his mother:

I saw innocent men shot down by the irresponsible militia. I walked four miles to have my jaw set. A stranger tried to make me accept a $10 gold piece. I was threatened with death for trying to help a small girl drag a trunk from a burning house, where her father and mother had been killed. A strange man gave me raw eggs and milk . . . (the first food I had had for twenty-two hours). I saw a soldier shoot a horse because its driver allowed it to drink at a fire hose which had burst. I had a Catholic priest kneel by me in the park as I lay on a bed of alfalfa hay, covered with a piece of carpet, and pray to the Holy Father for relief for my pain. . . . I saw a poor woman, barefoot, told to “Go to Hell and be glad for it” for asking for a glass of milk at a dairyman’s wagon; she had in her arms a baby with its legs broken. I gave her a dollar and walked with her to the hospital. . . .I was pressed into service by an officer, who made me help to strike tents in front of the St. Francis Hotel, when the order was issued to dynamite all buildings in the vicinity to save the hotel. I like him, and hope to meet him again. When he saw I was hurt, which I had not told him, not yet having been bandaged, he took me to his own tent and gave me water and brandy and a clean handkerchief.

The earthquake and the firestorms killed estimated 3.000 to 4.000 people, destroyed 28.000 buildings and the infrastructure of the entire city – but in a surprising rush people rebuild their homes and life, and just three year later most of San Francisco looked as if the earthquake never happened.

Seismology was still a young scientific discipline at the time of the earthquake in San Francisco, in part as a result of the lack of appropriate equipment like sensible tools to measure the tremors of earth. Worldwide there were only 96 seismographs operating, none of these in California. In the aftermath of the disaster, only three days later, the Governor of California announced the formation of the State Earthquake Investigation Commission, led by geologist Andrew C. Lawson of the University of California.
The commission concentrated its work on the San Andreas Rift, a nearby valley until then considered of minor interest and mapped geologically only in short sections. For two years Lawson and his team followed the rift along ponds, streams and hills on foot and horseback. They recognized that the rift follows almost the entire coastline of California for more than 1.000 kilometers (620 miles). During the April 18, earthquake almost 480 kilometers (300 miles) of this rupture were displaced horizontally, not vertically, as geologists had previously believed to be the source of earthquakes. The commission had discovered that earthquakes can be generated also along so called strike-slip faults.
The epicenter of the earthquake was at first located at the point with the largest observed displacement on land – however today the epicenter is believed to be situated below the Pacific Ocean, in accordance to the seismic waves coming from the sea as observed by the first eyewitnesses.
The results of the scientific investigation of the San Francisco earthquake led Henry Fielding Reid, a geology professor at Johns Hopkins University in Maryland, to propose a new theory regarding the origin of earthquakes, later dubbed the “theory of elastic rebound“. Reid’s hypothesis will have a revolutionary impact on the young science of seismology.


SLAVICEK, L.C. (2008): The San Francisco Earthquake and Fire of 1906. Great Historic Disasters. Chelsea House Publishers: 128
STARR, J.D. (1907): The California Earthquake of 1906. A.M. Robertson, San Francisco

Clash of the Titans: The Science behind the Iceberg that sank the Titanic

The tragedy of the “unsinkable” Titanic – lost in the cold water of the Atlantic – became part of history and pop culture, but the story of the main culprit that caused the disaster is mostly forgotten and only vague descriptions and some photos exists of the supposed iceberg(s). One famous photography taken from board of the cable ship “Minia, one of the first ships to reach the area in search for debris and bodies, shows a tabular iceberg, an unusual shape for icebergs in the northern Atlantic. The crew found debris and bodies floating in the vicinity and the captain assured that this was the only iceberg near the point of the collision. However most surviving Titanic testimonies described later the infamous iceberg with a prominent peak or even two.

Fig.1. The moment of the collision according to the sailor Frederick Fleet - one of the two men on duty as lookout in the night of the disaster (after EATON & HAAS 1986).

Fig.2. Journalist Colin Campbell, a passenger of the "Carpathia" - the first ship to approach the scene of the disaster the next morning and save the surviving passengers of the Titanic - described the iceberg for the "New York Tribune" (after EATON & HAAS 1986).

Fig.3. One of the many icebergs photographed in the morning of April 15, 1912. The passengers on the ship “Prinz Adalbert”, still unaware of the disaster of the previous night, reported later to have noted a “red smear” at the waterline of the white iceberg.

Fig.4. Photography of an iceberg from the cable ship "Minia", one of the first ships to reach the area in search for debris and bodies. The crew found debris and bodies floating in the vicinity of the depicted iceberg and the captain assured that this was the only iceberg near the scene of the collision (after Titanic & Nautical Resource Center).

Fig.5. Another iceberg, photographed five days later from board of the German ship “Bremen”, claimed to be the Titanic iceberg based on the vicinity to the location of the disaster and the description of the iceberg according to survivors. An "authentic" photography of the iceberg that sank theTitanic was worth a lot of money for the eager press, this also explain why so many photographs of icebergs were taken at the time.

Fig.6. Photography taken from board of the ship “Birma” of the same iceberg as seen by the passengers of the “Carpathia” (see also Fig.2.) – the first ship to approach the scene of the disaster and save the surviving passengers of the Titanic – and published at the time in the “Daily Sketch”. This iceberg has in fact some remarkable similarities to the iceberg as described by survivors of the disaster.  
Despite the question if one of the photos shows really the culprit iceberg, the remarkably number of spotted icebergs emphasizes the notion that in 1912 a quite impressive number of these white titans reached such southern latitudes.

The icebergs encountered in the North Atlantic originate mainly from the western coasts of Greenland, where ice streams deliver large quantities of ice in the fjords which lead to the Baffin Bay. Every year ten-thousand of small and large pieces of ice drop from the front of the glaciers and are pushed by the West Greenland Current slowly to northern latitudes, far away from ship routes. Following first the coast of Greenland this current is diverted by the Canadian coast to the south, forming the Labrador Current that circumnavigates Newfoundland and delivers the iceberg to the warm Gulf Stream. A more than 5.000km long journey full of obstacles and incessant erosion by the sun, the water and the waves. Only estimated 1 to 2% of large icebergs will, after a period of 1-3 years, reach latitude 45°N, crossing one of the most important route for ships of the entire Atlantic Ocean.

Fig.7. Schematic map of marine currents (blue= cold; red = hot) around Greenland, probable region of origin (West Greenland) and hypothetical route of the iceberg that hit the Titanic.

Apparently in 1912 icebergs were spotted remarkably often in this region and various hypotheses tried to explain this “anomaly”.  The years before 1912 were characterized by mild winters in Europe and possibly the northern Atlantic. It was therefore speculated that the (relative) warm temperatures increased the melting rate and activity of the calving glaciers on Greenland. 
Also a strengthened Labrador Current, pushing cold water and icebergs much more to the south, was proposed to explain the ice field that in the cold night 100 years ago forced various ships to stop along the Atlantic route. 
Both  hypotheses are based on the recorded values of Sea Surface Temperature (see this diagram by the Woods Hole Oceanographic Institution), which show an alternation of a warm and cold period  in 1900-1920.
A recent hypothesis – promoted by NG – proposes that an exceptional high tide prevented much of the larger icebergs to run, as normally would happen, on ground along the coasts of Baffin Bay. However considering that this tide occurred just some months before (January 1912) and the average velocity of an iceberg is low (0,7km/h~0,6mph), the Titanic iceberg had to take a straight course to arrive in time for his rendezvous with history – April 14, 1912.

Based on iceberg counts along the shores of Labrador and later in the Atlantic, also the year 1912 don’t seem to be necessarily such an anomalous event, but the disaster raised considerably the interest (and maybe perception) of the public for icebergs.

Fig.8. Iceberg counts (estimated before 1912) at 48°N, data compiled from the International Ice Patrol Iceberg Database.

In the days after the disaster bypassing ships encountered and photographed various icebergs. Some eyewitnesses claim to have noted red paint on some of them; however there is no conclusive evidence that one of these spotted white giants is really the iceberg that sank the Titanic. At least some weeks later the culprit iceberg, captured by the warm water of the Gulf Stream, melted and disappeared forever into the Atlantic Ocean.


EATON, J.P. & HAAS, C.A. (1986): Titanic Triumph and Tragedy. Haynes Publishing: 352
SOUTH, C. et al. (2006): The Iceberg That Sank the Titanic. The Natural World documentary film – BBC

April 10, 1815: The Eruption that Shook the World

I had a dream, which was not all a dream.  
The bright sun was extinguish’d, and the stars  
Did wander darkling in the eternal space,  
Rayless, and pathless, and the icy earth  
Swung blind and blackening in the moonless air;
Morn came and went – and came, and brought no day
Darkness” (1816) by Lord Bryon (1788-1824)

In the year 1816 Europe was slowly recovering from the Napoleonic wars, ended just one year earlier. After years of desperation and destruction people hoped for better times – but the summer that came was rainy and cold and on the fields the crops did not mature or rotted away, famine and diseases were the consequences. Also the north-eastern states of the US experienced snowstorms and frost in the middle of summer. The year 1816 has come to be known as the “year without a summer.

Fig.1. Development of costs in the years 1816-17 of important articles of food in Europe. Especially crops and bread, essential for the large and poor populations on the continent, experienced a massive increase in costs due the failed harvests. Meat was still a precious resource available only to a limited group of persons at the time; the reduced livestock therefore could still satisfy the demand (modified after ABEL 1974).

The strange behaviour of the weather was unexplainable at the time. Nobody could imagine that the origins of the strange phenomena were to be found on the opposite side of earth, where an entire mountain had annihilated itself in the largest volcanic eruption of modern history.
The estimated 4.000m high volcano of Tambora on the island of Sumbawa in Indonesia erupted with an intensity of VEI 7 – 100x stronger than Mount St. Helens. During the peak of eruption April 10, 1815 the mountain lost 1.300m height and catapulted estimated two million tons of debris, particles and sulphur components into the higher layers of the atmosphere. These aerosols reduced the solar radiation on earth’s surface and influenced worldwide weather patterns for years to come.
Thousands of people died by the direct effects of the four month lasting eruption, like poisonous clouds and gas, large pyroclastic flows and tsunamis. In the surrounding area of the volcano the vegetation was killed and the soil poisoned for years. Many more suffered from the climatic effects and the aftermath of the eruption. Almost the entire northern hemisphere, in a period with already cool climate, experienced an ulterior drop of temperatures, famine and diseases spread over the world.

Fig.2. "Volcano and fishing proas near Passoeroean, on the Java coast, Indonesia" by Thomas Baines (1820-1875).

Only one year later a detailed account of the catastrophe was published first in the “History of Java” (1817) by the English governor of Indonesia and naturalist Sir Thomas Stamford Bingley Raffles (1781-1826) and later incorporated in Lyell’s “Principles of Geology” (1850):

Island of Sumbawa, 1815. – In April, 1815, one of the most frightful eruptions recorded in history occurred in the province of Tomboro, in the island of Sumbawa, about 200 miles from the eastern extremity of Java.
In the April of the year preceding the volcano had been observed in a state of considerable activity, ashes having fallen upon the decks of vessels which sailed past the coast. The eruption of 1815 began on the 5th of April, but was most violent on the 11th and 12th, and did not entirely cease till July. The sound of the explosions was heard in Sumatra, at the distance of 970 geographical miles in a direct line; and at Ternate, in an opposite direction, at the distance of 720 miles. 

Out of a population of 12,000, in the province of Tomboro, only twenty-six individuals survived. Violent whirlwinds carried up men, horses, cattle, and whatever else came within their influence, into the air; tore up the largest trees by the roots, and covered the whole sea with floating timber. Great tracts of land were covered by lava, several streams of which, issuing from the crater of the Tomboro mountain, reached the sea. So heavy was the fall of ashes, that they broke into the Resident’s house at Bima, forty miles east of the volcano, and rendered it, as well as many other dwellings in the town, uninhabitable. 

On the side of Java the ashes were carried to the distance of 300 miles, and 217 towards Celebes, in sufficient quantity to darken the air. The floating cinders to the westward of Sumatra formed, on the 12th of April, a mass two feet thick, and several miles in extent, through which ships with difficulty forced their way. The darkness occasioned in the daytime by the ashes in Java was so profound, that nothing equal to it was ever witnessed in the darkest night. 
Although this volcanic dust when it fell was an impalpable powder, it was of considerable weight when compressed, a pint of it weighing twelve ounces and three quarters. “Some of the finest particles,” says Mr. Crawfurd, “were transported to the islands of Amboyna and Banda, which last is about 800 miles east from the site of the volcano, although the south-east monsoon was then at its height.” They must have been projected, therefore, into the upper regions of the atmosphere, where a counter current prevailed.  

Along the sea-coast of Sumbawa, and the adjacent isles, the sea rose suddenly to the height of from two to twelve feet, a great wave rushing up the estuaries, and then suddenly subsiding. Although the wind at Bima was still during the whole time, the sea rolled in upon the shore, and filled the lower parts of the houses with water a foot deep. Every prow and boat was forced from the anchorage, and driven on shore.  
The town called Tomboro, on the west side of Sumbawa, was overflowed by the sea, which encroached upon the shore so that the water remained permanently eighteen feet deep in places where there was land before. Here we may observe, that the amount of subsidence of land was apparent, in spite of the ashes, which would naturally have caused the limits of the coast to be extended.  

The area over which tremulous noises and other volcanic effects extended, was 1000 English miles in circumference, including the whole of the Molucca Islands, Java, a considerable portion of Celebes, Sumatra, and Borneo. In the island of Amboyna, in the same month and year, the ground opened, threw out water, and then closed again.

In conclusion, I may remind the reader, that but for the accidental presence of Sir Stamford Raffles, then governor of Java, we should scarcely have heard in Europe of this tremendous catastrophe. He required all the residents in the various districts under his authority to send in a statement of the circumstances which occurred within their own knowledge; but, valuable as were their communications, they are often calculated to excite rather than to satisfy the curiosity of the geologist. They mention, that similar effects, though in a less degree, had, about seven years before, accompanied an eruption of Carang Assam, a volcano in the island of Bali, west of Sumatra; but no particulars of that great catastrophe are recorded.


ABEL, W. (1974): Massenarmut und Hungerkrisen im vorindustriellen Europa. Versuch einer Synopsis. Hamburg-Berlin: 427
BOER, de J.Z. & SANDERS, D.T. (2002): Volcanoes in Human History: The Far-Reaching Effects of Major Eruptions. Princeton University Press: 295
OPPENHEIMER, C. (2011): Eruptions that Shook the World. Cambridge University Press: 392