The curse of the emeralds

"Listen to me,

because I am the first and the last,
I am the one who receives the honours
and the one who despises them...[]
I am the one who has fallen low
and the one who is beyond greatness."
The mother goddess after the ancient texts of Nag Hammadi (II-III century A.D.)

It is unknown when the first emeralds were discovered in the valley of Habach, in the Austrian province of Pinzgau, the only important locality of Europe where these green gemstones can be found.
It is sure that the ancient Romans know the richness in minerals of the Alps, however the oldest confirmed gem from Habach valley is the "Saint Louis" emerald of the French crown, forged in 1226, a 50 carat gemstone which isotopic signature matches the phyllite that characterize the region.
In 1669 the physician and naturalist Nicolas Steno visited a non specified locality in the Alps to study the emeralds found there - maybe it was the Habach valley. In 1797 the mining engineer of Salzburg, Caspar Melchior Balthasar Schroll, notes in his book "Jahrbuch für Berg- und Hüttenkunde", that "emeralds, until now were found only in the valley of Heubach in the Pinzgau".

Fig.1. A single crystal of emerald of the valley of Habach.

Fig.2. ... and many emeralds.

Despite rare and sporadic discoveries of large crystals without inclusions professional mining in Habach valley begun only in 1861. Here, nearly 2.200m a.s.l. tunnels were excavated into the rocks, a sequence of Biotite, Chlorite, Actinolite -and Tremolite bearing schists, rich in beryllium and chromium - essential elements to form under metamorphic conditions the emeralds.

Despite the invested effort, the wealth brought by the mining activities lasted short, in 1913 the English company owning the mine got bankrupt. Various companies and single holders followed in the years, all of them unsuccessful to gain profits from the mines. Then the Great War raged across Europe - there was no more interest in gemstones when people begun to starve.

Fig.3. Description of emeralds of the Habach valley and original specimens from the collection of Georg Gasser (1857-1931), eminent naturalist and author of a book about the minerals found in South Tyrol in the second half of the 19th century.

In 1950 to 1970 various mineral collectors tried their luck, but the hard work, the hostile environment and the isolation demanded a terrible toll - a kind of curse coming with all the things that men so desperately want to possess.
The German Carl Graab, heir of the mine after the second World War, got insane, Sebastian Berger, who some years later leased the mine, one day in 1986 gathered the entire explosive used for mining activity he could find and blasted himself to pieces.

Today the valley of Habach is still an important destination for mineral collectors, some rare emeralds can found in ancient landslide deposits consisting of the emerald bearing lithologies, or in the creeks and rivers coming from the mountains. Even the mine still exist, managed by a private collector, providing rarest specimens of the green fire for the enthusiast, hopefully with curse not included.

Bibliography:

KANDUTSCH, G. & WACHTLER, M. (2000): Die Kristallsucher - Ein Gang durch Jahrmillionen. Bd.2 Christian Weise Verlag, München: 160

A geologist riddle #3

Another geo-riddle, this time a bit challenging...

The photo shows a contact between a greenish in the foreground and a much brighter brownish lithology in the background. The appearance of these rocks reveal that they must have experienced some hard times in the past, but the contact is not the result of tectonic forces.
The green rocks contain a secret, revealed by some creeks in the landscape- a secret which brought great wealth to the inhabitants of the valley...

Further clues to solve the mysterious story of these rocks can also be found on my blog.

Understanding Black Glaciers

Glaciers are often covered by supraglacial debris in their ablation zone, in the Alps these "black glaciers", the geomorphologic term would be Debris Covered Glaciers (DCG), are relatively rare. In contrast such DCG are common in high mountain ranges like the Andes or the Himalaya, probably as consequence of the high sun-radiation levels in these regions.
Supraglacial debris is composed of material transported onto the glacier by rockfalls, avalanches, rubble of moraines and rocks melting out from the ice.

Fig.1. Huge erratic boulder on the Swiss glacier of Vorderaar after a picture published in a travel account of C. Wolf and M. Descourtis in 1785. By providing shadow and shelter to the underlying ice a pillar balancing the rock formed.

The thermal properties of this debris are profoundly different to blank ice and can significantly influence the glacier mass balance. Isolated rocks or a sparse cover, darker then the surrounding ice and snow, tend to absorb radiation of the sun and heat up, melting ice and increasing the loss of a glacier. A sufficient thick cover of rubble however isolates the underlying ice, and prevents or reduces melting and is so decreasing the loss of a glacier.
Research on the Swiss glaciers of Unteraar and Lauteraar have shown that a cover of debris ranging between a thickness of 5 to 20 centimetres shows higher temperatures on the superficial layer than the surrounding environment, however the thermal isolation is sufficient to reduces the ablation of the underlying ice by 32%.
The important influence of the debris cover on glaciers worldwide is however still poorly understand, hard to study and to quantify (variables like what kind of rock with connected physical properties is covering the surface and the highly variable thickness of the debris must be considered) and therefore neglected in many models to calculate future trends .

A new publication by SCHERLER et al. has analyzed 286 glaciers in the Himalaya using satellite images recorded from 2000 to 2008. The research confirmed that more than 65% of the glaciers are retreating with an average of 10 meters per year; however glaciers without debris cover are much faster in this general retreat then glacier with cover.

Fig.2. The glacierized Himalayan border region of Bhutan (bottom) and Tibet (top) seen in a satellite image. From the crest of the mountain range clean glaciers flow northwards onto the Tibetan Plateau, while DCG flow south into densely forested valleys. The debris cover on the glaciers depends of the topography of the surrounding mountains; steep slopes provide much more debris in form of rockfalls than gentle slopes (ASTER-image by NASA, 08 June 2006).

Many of the debris covered glaciers appear to be stable but the underlying ice shows no movement, it has become dead ice - former glacier ice that is not longer connected to the active glacier.

The research shows that to predict the behaviour of single glaciers the debris must be considered, also the comparison between well studied areas, like the Alps, to poorly covered high mountain ranges is not sufficient or even possible, more fieldwork, research and data on the mysterious DCG is essential.

Bibliography:

SCHERLER, D.; BOOKHAGEN, B. & STRECKER, M.R: (2011): Spatially variable response of Himalayan glaciers to climate change affected by debris cover. Nature Geoscience. doi:10.1038/ngeo1068

Namazu: The Earthshaker

According to Japanese myth the cause of earthquakes is the giant catfish Namazu or Namazu-e (the second term refers to the woodcuts of Namazu) living buried in the underground. Namazu is one of the yo-kai (in a very broad sense translatable as "monster"), creatures of Japanese mythology and folklore that were associated or caused misfortune or disasters. By moving his tail he can shake the entire earth and unfortunately he loves to cause trouble and havoc.

Fig.1. Japanese wood-block print showing a mythic catfish that causes earthquakes. Private collection, Berkeley, California (figure from KOZAK & CERMAK 2010). The horizontally outstretched catfish divides the picture in two parts, in the upper part there are rich merchants, in the lower part mourning people who have lost everything by the earthquake. The aftermath of the earthquake is depicted as possibility to redistribute the wealth; rich people have to divide their wealth with the poor to restore the general "cosmic" balance.

Namazu can be controlled only be the god Kashima, which with help of a powerful capstone pushes the fish against the underground and in such doing immobilized him. However the god sometimes got tired or is distracted from his duty and Namazu can move a bit and cause an earthquake.

Fig.2. The god Kashima immobilize with help of a capstone a guilty Namazu, demonstrating to a bunch of small catfishes, representing earthquakes of the past, the severe punishment for their behaviour (here a similar depiction of other punishments). However the catfish tries to defend his behaviour as response to his envy to other fish species, much more appreciated and popular in the traditional Japanese cooking (figure from LEWIS 1985).

Already in the Tokugawa period (1603-1868) the giant catfish was as a river deity associated to natural disasters, not surprisingly caused by water like floods or heavy rainfall. In these early traditions however namazu acts often as a premonition of danger, warning people from an imminent catastrophe or by swallowing dangerous water-dragons prevents even disasters.
Earthquakes, as apparently trembles of earth, were explained by movements of deities or creatures supporting the Japanese main islands, these creatures included gods, giants, an ox, dragons or snakes and a fish.
The dragon was a very old and powerful symbol imported from China and was in old times the main culprit of earthquakes, however during the 18th century, a giant Namazu gradually replaced the giant dragon in the popular imagination. This change from dragon to Namazu was minor, because dragons were also associated to water and rivers and so were closely related to the catfish in the popular imagination.
During the 19th century and after the earthquake of Edo (modern Tokyo) in October 1855 the wrongdoings of Namazu became more a punishment of human greed, it was believed that the catfish by causing havoc forced people to redistribute equally their wealth, in this role Namazu became yonaoshi daimyojin, the "god of world rectification".

Fig.3. Namazu in the form of yonaoshi daimyojin perpetuating his harakiri (in Japanese "Seppuku namazu", 1855) - with his sacrifice he will provide gold and money, dropping from his belly, for the poor people (figure from University Vienna). Some of these depictions have also magical powers: whoever take them home will be protected from earthquakes and experience "10.000 years of luck".

The classic images of Namazu (more than 300 are today known) were mainly a response of the Edo earthquake - by trying to depict also "positive aspects" (redistribution of wealth) of the earthquake the artists hoped to rise the morals of the survivors. Namazu was used also in satire, he is represented as a good-for-nothing, a coward acting only when the gods are gone, a reference to the aristocracy and incompetent civil servants.

Fig.4. A Namazu, representing the earthquake of Edo (modern Tokyo) in October 1855, is attacked by peasants and concubines (here a similar version), in the background help for the catfish is approaching - craftsmen, who will take profit of the reconstruction of the city. The earthquake of Edo, which killed thousand of inhabitants, coincided with the traditional "month without gods", believed a period when all of the gods gather in a secret temple. Taking advantage of the absence of Kashima, the coward Namazu rebelled and caused destruction and sorrows in the human world (figure from Wikipedia).

There are various versions of the myth with slight modifications; in some narratives the god doesn't use a rock, but a sword to nail the Namazu onto the ground. According to another version it is the god Kadori controlling the catfish, with the help of a giant and magical pumpkin. Also the main villain can be represented by a giant eel - Jinshin-Uwo - or a giant earthquake beetle - Jinshin-Mushi.

Fig.5. A version of Namazu controlled by Kashima with a sword (figure from Wikipedia).

Fig.6. ... and Kadori using a giant gourd made of a pumpkin (figure from SanAndreasFault.org).

Fig.7. A picture by the Japanese artist Kadzusa-ya Iwazô of 1842 lampooning the myth of Namazu, a Tanuki (a sort of mythical raccoon-dog with the ability to enlarge voluntarily parts of his body) is subduing the catfish with his giant scrotum (figure from Kuniyoshi Project).

Bibliography:

KOZAK, J. & CERMAK, V. (2010): The Illustrated History of Natural Disasters. Springer-Verlag: 203
LEWIS, T.A.(ed) (1985): Volcano (Planet Earth). Time-Life Books: 176

Online Resources:

SMITS, G. (): Earthquakes in Japanese History. (Accessed 17.03.2011)

A geologist riddle #2

An ulterior riddle for geoenthusiasts:

A crowd - but what are these people doing? Are they bemoaning somebody or something?
A woman seems to point out with her outstretched arm – a possible culprit for these sorrows?

23 January, 1556: The Jiajing Great Earthquake

"In the winter of 1556, an earthquake catastrophe occurred in the Shaanxi and Shanxi Provinces. In our Hua County, various misfortunes took place. Mountains and rivers changed places and roads were destroyed. In some places, the ground suddenly rose up and formed new hills, or it sank abruptly and became new valleys. In other areas, a stream burst out in an instant, or the ground broke and new gullies appeared. Huts, official houses, temples and city walls collapsed all of a sudden."
Contemporary witness report, found on Wikipedia.

The northern provinces of Shaanxi and adjacent areas were a densely populated region of the Ming-dynasty China (1368-1644).
The fertile soil of the plateaus of inner China had for centuries attracted people and the slopes consisting of the soft loess were used to dig caves as humble, but functional, homes.
It was in part a result of this type of construction that the January 23, 1556 earthquake (estimated magnitude of 8 to 8.3, epicentre located near the city of Huashan) caused such terrible destruction and devastation.
Many caves collapsed immediately killing the occupants and deadly landslides occurred - 97 counties in the provinces of Shaanxi, Shanxi, Henan, Gansu, Hebei, Shandong, Hubei, Hunan, Jiangsu and Anhui were hit. In some regions 60% of the population was killed, in sum presumably more than 820.000 people died - the greatest loss of human lives in written history.
As so often, the earthquake was followed first by devastating fires, then by famine, causing riots and starvation. For a half year after the earthquake aftershocks were recorded, significantly slowing down the reconstruction of the infrastructure.

In Chinese records this earthquake is often referred also as the Jiajing Great Earthquake, after emperor Jiajing ruling China at the time (1521 to 1567).

In contrast to other countries, like the nearby Japan, in China, where disastrous earthquakes also occurred frequently in history, no depictions of earthquakes can be found. A chief present Chinese seismologist at the State Seismological Bureau in Beijing, when asked why no historical images of earthquake disasters exist in China, simply answered "because they are not nice. We, in China, paint only beautiful and pleasant motives."


Bibliography:

KOZAK, J. & CERMAK, V. (2010): The Illustrated History of Natural Disasters. Springer-Verlag: 203
Figure 1: "The earth goat" symbol according to the Chinese animal zodiac.

Pseudoscience and prophecy of earthquakes

The self-declared seismologists Raffaele Bendani (1893-1979) affirmed in 1923 to have developed a method to foresee precisely earthquakes.
Lots of Italian sites have published in the last days such a presumed claim of Bendani that a swarm of earthquakes will destroy the Italian capital of Rome and cause worldwide havoc on the 11.05.2011 and subsequent year on the 5/6.04.2012.

Bendani was born in the Italian city of Faenza (Ravenna, Emilia-Romagna) and became interested in earthquakes after 1908, impressed by the devastations caused by the great earthquake of Messina in this year. He worked as mechanic and used self constructed seismographs to study the movements of earth. In 1923 he claimed to foresee an earthquake that would hit 2. January 1924 "with the probable epicenter in the Balkan Peninsula", not as claimed by the media the Italian province of Marche, a notoriously seismic zone. There was in fact one notable earthquake mentioned in this year in Italy, exact on the 2. January 1924 near the city of Senigallia with a magnitude of 5.6 after Richter, causing minor harms. Curiosly the online article affirms that Bendani missed the date by two days, so I assume the presumed prediction and the real earthquakes were never checked by the journalists. Despite the vague location of the epicenter, newspapers dedicated at the time to Bendani some coverage as "he who can predict earthquakes."

Bendani was an honest man who believed his own predictions, but he developed his entire theory ignoring the modern concepts of geology and especially plate tectonics - not yet recognized by the scientific community until the second half of the 20th century.
In the years Bendani continued to promote his "seismogenetic" hypothesis further: Earthquakes are caused by the gravitational pull of the moon on the earths crust helped by the aligned of the other planets. An idea that on a first superficial view seems reasonable, however improbable, became stranger and stranger in the following years.

To fit better his predictions he assumed an 11-year cycle, influenced by the activity of sun, he also invented a supplementary planet between Sun and Mercury, which he called, after his hometown, Faenza, to explain the presumed patterns of earthquakes.
Today there is still a foundation which conserves his work and according to the curator in Bendani´s papers there is no precise date and location for earthquakes in 2011. So already this is an unfounded claim diffused by uncritically sites in internet.

The dream to effectively predict an earthquake has inspired and generated both scientific and pseudoscientific work.
Many various methods and observations have been suggested as forecasting tools appearing at first look convincing, however no scientifically accepted forecasting method yet exists.
Some people remain convinced they can forecast earthquakes by pseudoscientific means, the proposed methods range from psychic experiences, weather, unusual animal activity, earth tides, eclipses, planetary alignments, unusual sounds, astrology and just plain ability. However most of them can not present a convincing physical mechanism for their method.
Such individuals take inevitable random coincidences or near hits as proof that their methods are valid, ignoring the failures, false alarms and invalid claims (the method of cherry picking - so often adopted by pseudoscientists).
On average, there are seventeen earthquakes of magnitude 4 or more somewhere in the world every day of the year and strong earthquakes with a magnitude 6 or higher occur somewhere on earth all three to six days.
A forecast that remains vague, missing exact position, time and magnitude is worthless as by plain chance it can hit an earthquake. Science can provide long-term statistical forecast of earthquakes, seismic activity is not distributed randomly on earth but concentrated on already mapped belts.

Fig.2. Earthquakes with a magnitude greater than 6 after Richter of the last 100 years. It is obvious from this figure that by shear chance it is possible to predict that somewhere an earthquake of such magnitude will occur (data from Exploring Africa's Physical and Cultural Geography using GIS).

The idea of planetary alignments, when several planets aligning relative to Earth influence the crust by their gravitational force, causing earthquakes is one of the most favourite explanation for earthquakes by pseudoscientists and the media.
In 1974, a book appeared forecasting doom during one such alignment that would occur in 1982. The book reportedly sold a large number of copies, especially in southern California, but finally there were no large earthquakes near the predicted time.
More recently there was the so-called Grand Alignment of May 5, 2000, when Earth and five other planets, plus the Sun and Moon, all came close to falling on a line. There were similar forecasts of earthquake disasters, but again none occurred - Astrology to predict earthquakes simply doesn't work.

Bibliography:

SHERMER, M. (2002): The Skeptic Encyclopedia of Pseudoscience. ABC-CLIO: 903
Figure 1: "The fool" according to an Italian Tarot-deck, image from Wikipedia.

The Expanding/Growing Earth

The geological model at the end of the 19th century was characterized by a static earth, slowly cooling and therefore shrinking until the molten interior became completely frozen.
The accumulating observations that continents once were connected led to the formulation of various hypotheses allowing vertical and horizontal movements of earths crust.
In the middle of the 20th century a new idea proposed that earth is in fact expanding, and the continents are remnants of old crust surrounded by younger rocks generated along the mid ocean ridges, explored between 1920-1960.

In 1956 Laszlo Egyed, professor of the geophysical institute of the Eötvös-University in Budapest, based on observations of variations in the sea level, proposed that earth was constantly growing. He explained the increase in volume of the planet by modification of mineral phases in the interior, with different specific densities. A much stranger idea to explain the assumed phenomena was proposed by the German physicist Pascual Jordan in 1966 - the increase of earth was imputable to the general dilatation of the space-time continuum.
Most work in the Expanding Earth/Growing Earth hypothesis was done by the German engineer Klaus Vogel, developing elaborate models of the continents fitting on a much smaller earth (20% smaller then today).

Fig.1. Warren Cray and Klaus Vogel discussing a model to illustrate the hypothesis of an Expanding Earth previous of 1988 (from OLDROYD 2007).

Influenced by the models of Vogel, the Australian geologist S. Warren Carey (1912-2002) became one of the most eminent supporters of the Expanding Earth.
The complex geology of New Guinea had convinced Carey that complex movements of earths crust were necessary to explain the structural geology of mountains. He developed a model encompassing mid ocean ridges and transform faults, but denied categorically subduction zones ("Subduction is a mythos!"), as superficial features of a very complicated cone structure, reaching down until the earth´s core.

However the Expanding Earth hypotheses failed to provide a convincing mechanism to explain a mass/volume gain, also simply measurements by satellites, as even Carey admitted, could disprove an increase in the radius of Earth ... as these data do, despite various other evidence.
Surprisingly (or maybe not) internet provided a second life to this idea...journalist and geologist Peter Hadfield summarizes the entire case:

"Why are so many people willing to believe a nutty 19th century idea over 50 years of solid and growing evidence for plate tectonics?
Because scientists are always conspiring to keep the truth from us, of course."



Bibliography:

OLDROYD, D.R. (2007): Die Biography der Erde. zur Wissenschaftsgeschichte der Geologie. Zweitausendeins-Verlag: 518

From Contractional theory to modern geology

Modern Plate Tectonics is the Grand Unified Theory of modern geology, however like many other theories it developed slowly, and in it actual form is only 50 years old. Plate tectonics is essential to understand the shape and distribution of continents, the genesis of mountains and sedimentary basins, the structure of mountains, why earthquakes and volcanoes occur and how dangerous they can become.

Already after the first maps of the American continent were published (1507 and after) and become public, the similarity between the coast of Africa and America intrigued geographers and naturalists, and this fascination continued in the following centuries. In 1620 the English philosopher Francis Bacon noted the jigsaw form in his "Novum Organum" and claimed that "it's more then a curiosity", and 38 years later the munch Francois Placet published a small booklet entitled "The break up of large and small world's, as being demonstrated that America was connected before the flood with the other parts of the world." He argued that the two continents were once connected by the lost continent of "Atlantis", and the sin flood beaked them apart.
The idea of the biblical flood explaining the shape of earth remained popular for the next 250 years.

Fig.1. Illustration from Thomas Burnet´s book "The Sacred Theory of the Earth", published in 1684, where he tries to explain the fitting shapes of the continents by the biblical flood. Parts of the crust of earth broke up (first drawing), releasing water from the underground. This water covers the entire planet (second drawing), and finally flowing back in the fissures leaves back a shattered crust that now forms islands and continents (last drawing).

The great French palaeontologist Buffon in his "Les Epoques de la Nature" (1717) not only addresses the age of earth, but also speculates about a former land bridge connecting Irland and America to explain the distribution of fossil shells found on both landmasses.
The American president and naturalist Benjamin Franklin by trying to explain fossils found on the summits of mountains propose in a letter to French geologist Abbd J. L. Giraud-Soulavie in 1782:

“Such changes in the superficial parts of the globe seemed to me unlikely to happen if the earth were solid to the center. I therefore imagined that the internal parts might be a fluid more dense, and of greater specific gravity than any of the solids we are acquainted with, which therefore might swim in or upon that fluid. Thus the surface of the earth would be a shell, capable of being broken and disordered by the violent movements of the fluid on which it rested.”

The great German naturalist and geographer Alexander von Humboldt explored South America from 1799 until 1804, and observed that the similarities between the two coastlines were not only restricted to a morphological pattern, but also to the geological features: mountain chains that seemed to end on one continent continued on the other, the Brazilian highland remembers the landscape of Congo, the Amazonian basin has it's counterpart in the lowlands of Guinea, the mountain ranges of North America are - geologically - very similar to the old European mountains and rocks in Mexico resemble those found in Ireland.

Fig.2. Columnar Jointing in the basalts of Regla, Mexico, as depicted in Alexander von Humboldts (1810) „Pittoreske Ansichten der Cordilleren und Monumente amerikanischer Völker.“, the accompanying text explains:
“The basalts of Regla, which are presented on this copper plate, are an incontrovertible proof of this identity of forms, which is noted on the rocks of different climates. Travelled mineralogist need only to look at this drawing to recognize the basalt forms in Vivarais, in the Euganean Mountains or in the foothills of Antrim, in Ireland. The smallest coincidences observed in the European rock-pillars are also found in this group of Mexican basalts. Such a great analogy let us assume a similar principle of formation acting under all climates in various temporal epochs, the basalts covered by compact limestone and clay-slate must be of different age than those who are resting on layers of coal and boulders."

But still the flood argument was a strong one, and so Humboldt argued that the Ocean represents a large, ancient river bed, flooded subsequently by the biblical catastrophe and forming the Atlantic Ocean.

The French zoologist Jean-Baptiste Lamarck (1744-1829) developed a surprisingly new hypothesis. To explain the discovery of fossil marine animals on the dry land he proposed that the continents "move" slowly, but irresistible, around the globe. The east coastlines of the single continents were eroded by the sea, but in the same rate new sediments were deposited on the west coast, so doing, the dry land in the past was a marine ground many times.
Unfortunately, also for the lack of evidence for his theory, Lamarck was not able to find a publisher for his "Hydrogéologie", and printed in 1802 on his own behalf 1.025 copies, but only a small number of books could be sold.

The new century saw the birth a new hypothesis to explain the shape of Earth, the Contractional theory, formulated by the American geologist James Dwigth Dana (1813-1895), explained mountains and continents as products of a cooling and subsequently shrinking earth.
After the theory of Dana the modern continents represent remnants of the former earth crust or at least the first parts of earth that solidified after the formation of the planet.
The Austrian Geologist Eduard Suess published in his multi-volume work "Das Antlitz der Erde” (1883-1909) this hand coloured map, showing the primordial continent - "cores" today separated by younger during the contraction of Earth formed and today water filled basins. He also suggested that the deep-sea trenches along the border of the Pacific are zones where the ocean floor plunges beneath the continents.

Fig.3. Hand coloured map showing the primordial continent -"cores" according to the Austrian geologist Eduard Suess "Das Antlitz der Erde" (The Face of the Earth) published in various volumes in the years 1883 to 1909.

But the theory of Dana and other “earth contraction” supporters couldn’t explain the irregular distribution of mountain ranges on earth and why areas with strong tectonic movements and earthquakes alternate with "quiet" areas, according to this idea, such features had to be distributed randomly on the surface of a cooling and shrinking body.

George Darwin, the son of Charles R. Darwin, explained the formations of the continents as result of the detachment of the moon from earth 57 million years ago by centrifugal forces.
The American geologist Frank Taylor in contrary tried to prove that the moon was captured by earth some 100 million years ago, and the resulting tide waves rip apart the single continent on the surface of the planet.

Antonio Snider-Pellegrini, an American scientist living in Paris, was the first in 1858 to publish a reconstruction of America and Africa forming a single continent. But in absence of a mechanism to explain such movements, he relayed again on the great flood, an obsolete idea even for those times.

To be continued...

Fig.4. This 1858 reconstruction by Antonio Snider-Pellegrini represents one of the first maps of a former supercontinent. In contrary to other naturalist of the time, Snider-Pellegrini assumed still a sudden and very fast movement, imputable to the biblical flood.

Bibliography:

FRISCH, W.; MESCHEDE, M. & BLAKEY, R. (2011): Plate Tectonics - Continental Drift and Mountain Building. Springer-Publisher: 212
MILLER, R. & ATWATER, T. (1983): Continents in Collision. Time-life books, Amsterdam: 176

Listening to the whispers of a volcano

"Descendant, descendants

It is about You
Today illuminates tomorrow with its light.
Listen:
Twenty times since the sun rose and if History does not lie,
Vesuvius burst into flames
Always exterminating those who tarried."
Commemorative plaque in the village of Portici, remembering the eruption of Vesuvius in 1631.

As so eloquent explained by many commenter's, the photo shows the volcanologist Frank Alvord Perret listening with the help of a selfmade geophone to the whispers of volcanic activity in the Campi Flegrei.

Fig.1. F. A. Perret with an improvised "geophone," listening to subterranean noises at the Campi Flegrei, Italy, probably in 1906-1907 (the photo was published in 1907). As an able technician, Perret probably used a microphone to amplify the rumours from inside the earth; a cable can be seen in front of his face connecting the geophone to a loudspeaker positioned on his ear, in the other hand he holds a battery or control device. Photo from "The Day’s Work of a Volcanologist." The World’s Work, V. 25, November, 1907.

Frank Alvord Perret (1867-1943) was an American inventor and volcanologist, he studied particularly the volcanoes of the Canary Islands, Japan, Hawaii, Martinique -the infamous Pelee nearly killed him - and Italy, especially the area of Naples became his favourite field of research.

He studied physics at the Brooklyn Polytechnic Institute, but didn't graduate and became self-educated as an electrical engineer. As a gifted inventor and technician for a period he worked in the laboratories of Thomas Alva Edison, developing new motors, dynamos and batteries. In 1886 he became independent with his own "Elektron Manufacturing Company", witch in the followings years experienced a notable success.
His health began to fail in 1902, however, and while on a recuperation visit to the Caribbean, he stopped by Martinique to visit the ruins of St Pierre, the desolation of destruction experienced here impressed him profoundly.
In 1904 during a visit in Italy Perret meet Raffaele V. Matteucci, director of the volcanological station of Mount Vesuvius, who got him interested even more in the young field of volcanology.
Do ongoing problems in his health in 1906 he abandoned definitively his business to dedicate himself to a less strenuous and dangerous engagement: studying active volcanoes!
He observed Vesuvius in the years 1906 to 1921, dedicating to the eruption of 1906 "the clearest and most complete report ever of a volcanic eruption and its aftermath" (Milderd Giblin, in 1950). Mildred Giblin from the Geophysical Laboratory of the Carnegie Institution of Washington, the former working place of Perret, commended Perret's work by stating that the:

"scientific contributions of Mr. Perret are unique in that no other volcanologist had the time and opportunity to make so thorough and varied observations on so many types of active volcanoes. He was a daring and sagacious researcher, indefatigable in his quest for information. He was a proficient and discerning photographer, and his publications are freely illustrated with fine pictorial records."

During the eruption of 1906, the strongest since 1631, Perret and Matteucci used the Osservatorio Vesuviano - an observation building constructed in 1841 on the north-eastern slope of Vesuvius, as base.
The volcano spit out rocks and lapilli, and strong earthquakes occurred.
Perret remembers:

"In the building it was difficult to cross the rooms maintaining the balance if not by holding a hand against the wall."

Perret abandoned the building to see if the tremors occurred also outside:

"The effect was the same. Like the mantle of a steel boiler, the entire mountain was pulsating and vibrating continuously."

One day Perret awoke in the bed of the observatory by a strange rumour, a buzzing heard in the ear in contact to the pillow. Rising his head the rumour disappeared, Perret rose from the bed and put the iron bars of the bedstead between his teeth - now he could feel a constant tremble emanating from the underground.
Perret had discovered the Harmonic tremors, constant vibrations often preceding a volcanic eruption, generated probably by uprising magma inside the volcano. Some days later Vesuvius entered in the most active phase of the eruption.

Fig.2. Example of seismograph recording of harmonic tremor by the USGS, image from Wikipedia.

In 1911 he was one of the initiators of the first permanent monitoring stations installed on the crater of the Halemaumau on Kilauea, and in 1912 Perret begun with his research on the Hawaiian volcano, here he carried out the first direct measurements of the temperature of molten lava.

When in 1929 the Pelee on the French Caribbean island of Martinique erupted, Perret was one of the first geologists to visit the volcano. In the three years of volcanic activity he conducted numerous observations and investigations, and in 1930 he built a small hut on the crest of Morne Lenard above the Rivière Blanche valley.
Here one day he was surprised by two pyroclastic flows, rushing from the crater of Pelee, following the two valleys delimitating the crest. Luckily he survived unharmed; his only remorse was the inability to recover some gas probes from inside the flow.
He studied the island and the mountain discontinuously for the next ten years, and could often be observed during field investigations, well-dressed with Van Dyke beard and straw hat.
In 1932 he founded the volcanological museum in Saint-Pierre, which still today carries his name, to educate the native population but also to remember them of the dangers of an active volcano.

In 1940 Perret returned to the United States, dedicating himself to the compilation of various books about volcanoes, he could publish them only in part until his dead, just three years later.

Bibliography:

LEWIS, T.A.(ed) (1985): Volcano (Planet Earth). Time-Life Books: 176
LOCKWOD, J.P. & HAZLETT, R.W. (2010): Volcanoes Global Perspectives. Wiley-Blackwell Publishing: 540
PERRET, F. A. (1924) The Vesuvius Eruption of 1906. Washington, DC, Carnegie Instution.
PERRET, F. A. (1935) The Eruption of Mt. Pelée, 1929-1932. Washington, DC, Carnegie Instution.

Online Resources:

GIDWITZ, T. (2005): The Hero of Vesuvius. (Accessed 18.01.2011)
KIEFFER, S.W. (05.02.2011): A shocking James Bond volcano breaks windows 8 km away! (Accessed 07.02.2011)
SMITH, J. (2005): Frank A. Perret 1867 - 1943. Carnegie Institution of Washington. (Accessed 18.01.2011)
USGS ed. (25.08.2005): A pioneering volcanologist narrowly beats the Reaper. Hawaiian Volcano Observatory (Accessed 18.01.2011)

A geologist riddle #1

A tentative riddle with an image I came across accidentally: a gentleman using his mobile phone?

Probably not - but then who is it and what is he doing and why?

17 January, 1995: The great Kobe earthquake

In the morning of the 17 January 1995 at 5.46 (local time) a strong earthquake shattered the Japanese city of Kobe and despite many constructions and buildings were assumed earthquake-proof, more than 6.000 people were killed and more than 300.000 people lost their homes.

The earthquake generated along the intersection of the Nojima fault with the Suma fault, 16 kilometres below the Akashi strait, 20 kilometres to the west of the city.
The main shake was preceded by a series of weak trembles, registered only by the seismometer in Osaka, then for 14 to 20 seconds earth trembled reaching a magnitude of 7.2 after Richter (7 according to the Japanese intensity scale - shindo, the strongest possible value), the strongest earthquake in West Japan since 1923.

Fig.1. Fault model of Yoshida et al. (1996) for the 1995 Kobe earthquake. Two rectangles represent the surface projections of the fault segments and thick lines indicate their shallower sides. The solid star with a focal mechanism solution is the epicenter of the main shock determined by Katao et al. (1997), and gray lines are active fault traces, after KOKETSU et al. 1998.

The earthquake damaged seriously the traditional buildings of the housing area in the west and east of the city; people were surprised asleep in their homes and killed or injured by the collapsing houses. The expressway of Hanshin, opened in 1962, was build according to the earthquake-resistant directives of the time; however it collapsed in 1995 for a length of 5 kilometres.

Fig.2. Damage from the Great Kobe - also named Hanshin - Earthquake is kept intact at the Earthquake Memorial Park near the port of Kobe. The elevated Hanshin Expressway, in the background, was partially toppled by the earthquake, image from Wikipedia.

It was not expected that Kobe could be hit by such a strong earthquake, in fact the earthquake did generate from a local thrust faults-system, not directly connected to the subduction zone of the Philippine Sea Plate southwest of the island of Honshu.

The harbour of Kobe, one of the most important in the world, was severely damaged and inundated by water coming from the underground, eyewitnesses-accounts report from fountains of water coming from fissures of the ground. The vibrations of the earthquake compacted the sand used to rise up artificially the harbour, and groundwater was pushed out of the vacancies of the sediment, the soil became liquefied and many fundaments of construction simply toppled in the water-sand mixture.



Many survivors claimed later that help was poorly organised, in the following days food, water and cloths became scarce. People travelled on overcrowded streets to the nearby city of Osaka to organize these goods. The national government changed its disaster response policies in the wake of the earthquake and improved construction directives to account modern understanding of earthquakes and their occurrence.

Bibliography:

KOKETSU, K.; YOSHIDA, S. & HIGASHIHARA, H. (1998): A fault model of the 1995 Kobe earthquake derived from the GPS data on the Akashi Kaikyo Bridge and other datasets. Earth Planets Space, 50: 803-811

Mount Etna: Significance in the history of volcanology

The oldest volcanic deposits of Mount Etna are 230.000 years old; the constant activity of the volcano has been noted for the last 3.500 years and especially the last 400 years are well documented.

Historic eruptions are recorded for the year 479 B.C., 1329, 1381 and 1536, one of the largest and most destructive eruptions was a flank eruption in March-July 1669 which produced the cinder cone of Monti Rossi and a 14 km long lava flow which, despite it was partially deviated from its path by an artificial dam, destroyed part of the city of Catania, obstructed the harbour and caused  a lot of victims.
 
Cinder cones on the slopes of Etna erupted again in 1763, 1811, 1852, 1865, 1879 and 1892. In the 20th century, concentrated on two main branches extending from the crest, lava erupted in 1908, 1910, 1911, 1918, 1923, 1928, 1942, 1947, 1949 and 1950-1951, 1964, 1968, 1971, 1981, 1983, 1989 and 1991 (the most voluminous eruption since 1669) to 1993.
 
The activity continues well into the 21th century. Since 2001 Etna is more or less active (in 2002 and 2003 the volcano produced spectacular ash plumes), with a short pause in 2008, since 2011 the volcanic activity increased again.

The constant activity and the spectacular size of the volcano made it an important destination of early travelling geologists.

Fig.1. The volcanic eruption of Etna explained by a whirlwind emanating from the underground, according to Comte A. de Bylandt-Palstercamp (1836): "Théorie des volcans". This reconstruction was based by observations of ancient scholars and myths, especially the believe that earth is formed by the interactions of the four elements: water, earth, fire and air.

Lord William Hamilton (1730-1803), British ambassador in Naples, became fascinated by volcanoes and Mount Vesuvius. Hamilton used the vegetation cover to estimate the age of the lava flows of Vesuvius and also for the vegetation covered cinder cones of Mount Etna he assumed a very old age. These old ages implied that volcanoes can be active for thousand of years, maybe even longer times, an important insight in a time when earth was considered only 6.000 years old and volcanoes only local features, with little to no significance in shaping the landscape.
  Fig.2. View of Mount Etna from Hamilton´s "Campi Phlegraei, Observations on the Volcanoes of the Two Sicilies"; Plate 36, Mt. Etna (1776), based on a painting by Pietro Fabris (an artist hired by Hamilton to illustrate his research); the volcano was quiescent when they visited Sicily in 1769. The lower slopes of the mountain are dotted with minor cones, the prominent double cone of Monti Rossi (on the left) had been formed during the great eruption of 1669, together with a huge lava flow (visible behind the buildings) that had threatened to engulf the city of Catania.

Based on the assumed local nature of volcanoes, the French geologist Elie de Beaumont, following research by the eminent German geologist Leopold von Buch, published in 1838 a study suggesting that Etna lavas had been erupted in thin sheets on a subhorizontal surface, accumulating to a considerable thickness and only later tilted and pushed upwards by intruding magma. Volcanic craters where according to this popular hypothesis caused by the elevation of the ground, breaking apart the lava would simply flow out of the so formed hole.
Charles Lyell visited Etna on a number of occasions and in 1858 published a monograph: "On the Structure of Lavas which have consolidated on Steep Slopes: with Remarks on the Mode of Origin of Mount Etna and on the Theory of "Craters of Elevation."
From the morphology and flow characteristics of historic and ancient lava flows he deduced that they had solidified on steep flows, also he recognized that the lava flows came from two distinct eruptions, so he argued:

"...we must abandon the elevation-crater hypothesis: for although one cone of eruption may envelop and bury another cone of eruption, it is impossible for a cone of upheaval to mantle round and overwhelm another cone of upheaval so as to reduce the whole mass to one conical mountain."

Finally a volcanic eruption in the Mediterranean Sea will confirm Lyell´s observations and make it clear that volcanic mountains don´t form like a bubble, but grow over time: this important event in the history of geology will be the birth of the island of Ferdinandea, explored by the crew of the ship "Etna".

Fig.3. Topographic map of Mount Etna in 1823 (reprinted in 1844 in Leonhard "Vulkan Atlas") by Mario Gemmellaro, displaying lava flows, cones and villages in the surroundings of the volcano.

Bibliography:

RUDWICK, M.J.S (2005): Bursting the limits of time - The reconstruction of Geohistory in the Age of Revolution.The University of Chicago Press, Chicago, London: 708RYMER, H.; FERRUCCI, F. & LOCKE, C.A. (1998): Mount Etna: monitoring in the past, present and future. Geological Society, London, Special Publications 1998; v. 143; p. 335-347