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Earth of fire

Actualité volcanique, Articles de fond sur étude de volcan, tectonique, récits et photos de voyage

Articles avec #eruptions historiques catégorie

Publié le par Bernard Duyck
Publié dans : #Eruptions historiques

Seven years ago, began a sudden and powerful eruption, described VEI 4 on Okmok volcano's caldera in the center of the Aleutian arc.

On 12 July 2008, the eruptive activity began just a few hours after a subtle increase in seismicity, followed by a short sequence of seismic swarm, noticed retrospectively.

The first explosions took away a part of the cone D, in the central-eastern sector of the caldera wide of 10 km. The most energetic phase takes place during the first ten hours of the event. Data from the GOES satellite and comparison with Puff ash dispersion model indicates a height of the initial eruption column 16 km.

 

Okmok eruption plume and of 12 July 2008 - doc. AVO

Okmok eruption plume and of 12 July 2008 - doc. AVO

Okmok - cumulative emissions of sulfur dioxide from 12 to 20.07.2008 - Doc. NILU / Nasa Earth Observatory

Okmok - cumulative emissions of sulfur dioxide from 12 to 20.07.2008 - Doc. NILU / Nasa Earth Observatory

Localistion of Okmok volcano in the Aleoutian arc - doc. AVO

Localistion of Okmok volcano in the Aleoutian arc - doc. AVO

Over the next five weeks, hundreds of millions of cubic meters of tephra and lahar deposits will cover much of the northeast of the island Umnak. Within the caldera, almost continuous hydrovolcanic explosions will accumulate several tens of meters of tephra, wet and fine grain. Explosive activity will completely disrupt the water table and standing waters in the caldera; a new tephra cone will be built, reaching finally 200 meters height. This eruption is the first volcanic event of phreatomagmatic dominance marking the US since the eruption of the maar Ukinrek (north of the Aleutian arc) in 1977.

On July 23, many lahars are noticed by a farmer; their formation is not identified with certainty: remobilization of ashes by rain, water vapor condensation syn-eruptive, water loss during wet ash falls, snow melts, or combination of factors?

 

The eruptive plume of Okmok seen on August 3, 2008 from a plane of Alaska Airlines flying at an altitude of 10.7 kilometers - photo Burke Mees

The eruptive plume of Okmok seen on August 3, 2008 from a plane of Alaska Airlines flying at an altitude of 10.7 kilometers - photo Burke Mees

On 2 and 3 August, the eruptive plume increases in height, strength and support of ashes; this coincides with an increase in the amplitude of tremor. This enhancement of activity do raise the alert level for aviation in Red by the AVO. During the first two weeks of August, the intensity of the eruption and the plume height decrease, and ash emissions stopped on August 19. A survey reveals a single vent contained in a tephra cone with steep walls.

Field observations in September, combined with the analysis of photographs will however indicate that the eruption occurred at the start of a series of vents, which opened during the first two weeks, and arranged on a 2 km line in the caldera. A tephra cone has been built above the 2008 longer active vent. The explosion and the collapse of craters, to the west of D cone, formed a depression that is filled with water and formed a lake of 0.6 km².

More details on the website of the AVO.

Caldera of Okmok - the newly formed cone and lake - Doc. AVO

Caldera of Okmok - the newly formed cone and lake - Doc. AVO

Sources :

- AVO / Alaska Volcano Observatory - link

- Global Volcanism Program - Okmok

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Publié le par Bernard Duyck
Publié dans : #Eruptions historiques
 Tambora, the caldera - Doc. Nasa 03.06.2009

Tambora, the caldera - Doc. Nasa 03.06.2009

To complete the serie on the Tambora, it is necessary to examine its evolution before and after the eruption of 1815.

The formation of the stratovolcano:

Based on the revelations of the bicentennial eruption , the former Tambora consists of superimposed sequences of lava flows (about 40%) and pyroclastic deposits. The layers are thick of 1 to 4 meters, laterally discontinuous, and with a dip of 20-30 ° from the center of the caldera.

Many radial dikes of 50 cm. to 3 m. thick, cross the substrate. In the eastern wall of the caldera, some dykes extend from the floor to a few meters from its edge, uninterrupted. A mismatch occurs in the formation, with generally older deposits in the northern areas of the caldera, and younger  in southern and eastern walls.

 

Gunung Tambora - photo boguairadek

Gunung Tambora - photo boguairadek

Tambora - reading of interbedded layers on the walls of the current caldera - photo Rizal Dasoeki / VSI

Tambora - reading of interbedded layers on the walls of the current caldera - photo Rizal Dasoeki / VSI

The morphology of the flanks suggests the pre-existence of a large cone (about 4,300 m. High), with a central vent, emitting lava flows that descended the steep flanks. Most pyroclastic have been produced by fragmentation in the eruption, leaving large beds of slag. Intermittent explosive eruptions have produced pyroclastic flows, whose deposits are found in the ravines away.
 

Diagrams reconstructing the original form of Tambora, left - and its current form, right - doc.Armstrong SompotanDiagrams reconstructing the original form of Tambora, left - and its current form, right - doc.Armstrong Sompotan

Diagrams reconstructing the original form of Tambora, left - and its current form, right - doc.Armstrong Sompotan

The evolution of the stratovolcano stopped with the formation of a first caldera in the western part of stratocône, approximately 4 to 5 km in diameter and 700 meters deep, asymmetrical to the future caldera of 1815. The formation of this first caldera is supposed to be related to an explosive eruption, or a ignimbritic episode.

This first caldera is partially filled by a series of thick horizontal lava flows confined entirely in the caldera. There are 16 different lava flows, most of 15-20 meters thick, and separated by  scoria and tuff, tick of several meters. In total, these formations are thick from 300 to 400 meters. They do not involve intrusive dykes and are not hydrothermally altered. Their composition is typically  clinopyroxene-
porphyritic, often with phenocrysts of plagioclase and olivine.

A brown tuff formation is the last that preceded the eruption of 1815, produced by a subplinienne activity and pyroclastic surge. The deposits are gray-brown to brown, thick of 5 to 10 meters, made up of semi-consolidated tuff in interbedded layers of yellowish-gray pumice and scoria.

 

Tambora 2013 - fumaroles on the floor of the caldera - photo Morten Haan / Germany Georesearch Volcanedo

Tambora 2013 - fumaroles on the floor of the caldera - photo Morten Haan / Germany Georesearch Volcanedo

After the eruption of 1815:

Proximal deposits, well exposed on the walls of the present caldera, consist of pyroclastic  and pyroclastic flows
deposits. Their deposition was influenced by the morphology of the first caldera, not yet filled at the start of the eruption of 1815.

During or just after the formation of the caldera, the edges of it are known various collapses forming debris flows that spread over one or two kilometers on its floor. The floor of the caldera was then covered with sand and gravel from erosion of the walls and mudslides.

 

Tambora 07.2014 - pressurized gas escaping into the northeastern region of the caldera and sulfur deposits - photo Georesearch Volcanedo Germany

Tambora 07.2014 - pressurized gas escaping into the northeastern region of the caldera and sulfur deposits - photo Georesearch Volcanedo Germany

During the 19th and 20th centuries, lava flows and small lava domes were extruded on the floor of the caldera.

The Global Volcanism Program identifies three eruptive episodes since 1815 :
- In August, 1819, an eruption of VEI 2.
- In 1880 ± 30 years, an eruption of VEI 2 marks the southwestern part of the caldera.
- In 1967 ± 20 years, the northeastern part of the caldera is the seat of a small eruption.

 

Tambora - cumulative seismicity per month between April and August 2011, excluding tremor - PVBMG doc / GVP

Tambora - cumulative seismicity per month between April and August 2011, excluding tremor - PVBMG doc / GVP

In 2011, an increase of activity is reported between April and September 8 (PVMBG), with increased levels of Tambora alert to III (increased seismicity, tremor, and emissions of fumes). White plumes high of 50 to 70 m. above the edge of the caldera are reported.

In 2013, the alert level is raised to 2, based on seismic data and visual observations by the PVMBG.

Sources :

- Global Volcanism Program - Tambora

- Vulcanological Survey of Indonesia - Geology of Tambora volcano (2006)

- Armstrong Sompotan - Tambora

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Publié le par Bernard Duyck
Publié dans : #Eruptions historiques

The eruption of Tambora did not leave only victims ... Volcanic emissions affect the climate, and are also responsible for optical phenomena: that veil of aerosols, mainly sulfur dioxide / sulfuric acid, can change the colors of the sky at sunset.
 

 "Chichester Canal" by JMW Turner (1828)

"Chichester Canal" by JMW Turner (1828)

Professor Zerefos gave a key to this change, in an article in the Journal of the European Geosciences Union: "In the coloring of the sunsets, this is the way the brain perceives green and red which contains important information on the environment. "

The painters of the 19th century have reproduced these specific colors without understanding the cause.

This eruption has also allowed the artistic evolution of William Turner, who went from an agreed paint to the color magnification; his attraction to the representation of the atmospheres place him as a pioneer of "Impressionism". It will go even further, removing the descriptive side and limited to the colorful juxtaposition, as in his "Sunset" in 1840 ... according to some, "the first fruits of lyrical abstraction", another movement of yhe modern painting.
 

"Sunset" - by W.Turner (1840)

"Sunset" - by W.Turner (1840)

The climatic effects touching Switzerland will influence the literature of the time.

That year, a villa near Lake Geneva in Switzerland, home to Lord Byron. During the summer, it is visited by Mary Shelley and his immediate family; retained inside because of the incessant rain, Byron offers his guests to write each a ghost story.

Byron wrote a fragmented scenario that allowed a friend to be inspired to write "Dracula".

Mary Shelley, inspired by reading the Fantasmagoriana and under the influence of opium, had a nightmare where she has a vision of "a pale student looked at the thing he had animated." She finished writing "Frankenstein" in the spring of 1817.

"Frankenstein or the Modern Prometheus," is considered the precursor novel of science fiction.

John William Polidori will write about "The Vampire".

 

On the left, frontispiece of the 1831 edition of "Frankenstein" - to the right, Lord Byron - 1824 portrait by Thomas Phillips (1770-1845) - UK Government Art Collection - one click to visualize On the left, frontispiece of the 1831 edition of "Frankenstein" - to the right, Lord Byron - 1824 portrait by Thomas Phillips (1770-1845) - UK Government Art Collection - one click to visualize

On the left, frontispiece of the 1831 edition of "Frankenstein" - to the right, Lord Byron - 1824 portrait by Thomas Phillips (1770-1845) - UK Government Art Collection - one click to visualize

This period coincides with the publication of Lord Byron's poem "Darkness"  ... here are the opening lines:

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

 

Bright colors and dark thoughts ... inspired by the eruption of Tambora and his atmospheric effects.

 

Sources :

- Darkness, poème de Lord Byron - link

- European Geosciences Union - Famous paintings help study the Earth’s past atmosphere - 25.03.2014 - link

- Further evidence of important environmental information content in red-to-green ratios as depicted in paintings by great masters - C. S. Zerefos & al. - link

- Zerefos, C. S., Gerogiannis, V. T., Balis, D., Zerefos, S. C., and Kazantzidis, A.: Atmospheric effects of volcanic eruptions as seen by famous artists and depicted in their paintings, Atmos. Chem. Phys., 7, 4027-4042, doi:10.5194/acp-7-4027-2007, 2007.

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Publié le par Bernard Duyck
Publié dans : #Eruptions historiques

The effects were overall ... "the year without summer"

The eruption released a huge volume of sulphate aerosols, estimated at 175 trillion pounds or {175.1018 - Source E.Klemetti - A trillion is equal to one million to the third power ie a million million million (106x106x106), hence the term.} generating an atmospheric temperature decreases.

It has also disrupted the Jet Stream route over the Atlantic, which changed during four years the climate of the northern hemisphere.

Relative declines of temperatures in degrees centigrade related to eruptions - Doc. Berkeley

Relative declines of temperatures in degrees centigrade related to eruptions - Doc. Berkeley

Sulphate concentrations in the cores drilled in Greenland - Those of years 1815 and following are related to the eruption of Tambora - Doc. Dai, J .; Mosley-Thompson, E .; Thompson, L. G. (1991). "Ice core evidence for explosive volcanic eruption tropical year six years preceding Tambora". Journal of Geophysical Research (Atmospheres) 96 (D9): 17361-17366.

Sulphate concentrations in the cores drilled in Greenland - Those of years 1815 and following are related to the eruption of Tambora - Doc. Dai, J .; Mosley-Thompson, E .; Thompson, L. G. (1991). "Ice core evidence for explosive volcanic eruption tropical year six years preceding Tambora". Journal of Geophysical Research (Atmospheres) 96 (D9): 17361-17366.

In the spring and summer of 1815, a dry, persistent fog is observed in the NE. of the United States Fog blushed and weakens the sunlight, so that one can observe with the naked eye contours.

The summer of 1816 was marked in the northern hemisphere by extreme conditions, to the point that calls 1816 "the year without summer". Temperatures generally decrease by 0.7 ° C-3 ° C, enough to cause problems for global agriculture for many years. In June, frosts are reported in Connecticut and snow in the states of New York and Maine. These conditions last for the next three months which reduces plant growth period and leads to disastrous harvests.

Many American historians speak of the "Year Without a Summer" as a key motivation for the westward movement and the rapid settlement of what is now western and central state of New York and US Midwest. In New England, many people were victims of the 1816, nicknamed "Eighteen hundred and froze to death", ie "The year 1800 where he froze to death" and there are dozens of thousands of farmers who left for the northern Midwest (which then constituted the Northwest Territories), where they hoped to find a richer soil and better growing conditions for vegetation.

Asia was hit: in China, unusually low temperatures combined with torrential rain did fall rice production in Yunnan, with a famine in the key. In other provinces, the fields were ravaged by the summer frost or snow. Taiwan, however, characterized by a tropical climate, known frost and snow.

Europe has experienced this "volcanic winter" : cold and rainy, snowy winters ... followed by the flood of large rivers and floodings, crop failures, famine and typhus epidemic ... The continent, not yet restored of the Napoleonic Wars knew subsistence riots, with looting grain stores.
 

Summer 1816 - temperature anomalies recorded in Europe - doc.CNCEP

Summer 1816 - temperature anomalies recorded in Europe - doc.CNCEP

 BRESSAN prices of various foodstuffs - price increase in development in the years 1816-1817 in Europe - Tambora foodprices - Development of costs in the years 1816 to 1817 of major items of food in Europe.

BRESSAN prices of various foodstuffs - price increase in development in the years 1816-1817 in Europe - Tambora foodprices - Development of costs in the years 1816 to 1817 of major items of food in Europe.

This decline reached 1 to 1.5 ° C below normal in the British Isles. (Oppenheimer 2003), where the summer is cold and wet - rain and snow fell incessantly in July 1816 - leading to a lack of harvests and famine. Typhus hit many villages in England and Scotland. In Ireland, nearly 800,000 people are infected with the epidemic and 4,300 die of the combined ravages of starvation, dysentery and fevers.

In Hungary and Italy, there are reports of red-brown snow events throughout the year ... the case is volcanic ash in the atmosphere.

Switzerland, private of access to the sea and supply, experienced a famine and subsequent violence as the government declared a state of emergency. It is estimated that the mortality rates in 1816 were two times higher than average, with a total of 200,000 deaths.

The situation is similar in France, in all provinces. Various testimonies coming illustrate it.

On the wall of a house in Heiligenstein, Alsace, we read:
Im Jahr 1817 ist diese Hütte gebauet worden, in welchem ​​Jahr für ein man Furtel Wäissen bezahlte 120 fr für ein Sack Erdapfel 24 fr für ein Wein Ohmen 100 fr. Jacob Stiedel.
(In 1817 the cottage was built and this year we paid 120 francs for a measure of wheat for 24 francs a potato bag, 100 francs for a Ohmen (50 liters) of wine Jacob Stiedel. .)

 

The Hungersjohr in Heiligenstein - Gustave Graetzlin

The Hungersjohr in Heiligenstein - Gustave Graetzlin

Nebinger Leonard (born 1794), who was the mayor, tells in his memoirs that terrible year:
"1817 was a year of incredible expensive. A quarter of wheat worth 150 francs. There was some wine and it was sour. Eight days before the harvest snow fell up to half the height of a shoe, so that in many broke the stocks and many trees on the ban of the town and in the forest broke under the snow. That year they could not work the soil vineyards as it had rained. In this quarter of famine, one ohm of Klevener (a white wine Alacien) of 1811 was worth 80 francs, a wheat quarteau 150 francs, a potato sack 24 francs, a measure of beans 15 to 16 "sous". The farmers market no longer able to know what they were asking, so more than once, when they had exaggerated, people overthrew what they had on their display and the poor, who stood behind them their flying often imitated by German officers who were still in the region. The poor were in the forest, in the cuts were picking herbs, cooked them, hacked them like cabbage and ate them. But all we managed to eat that year did not feed so that people still hungry an hour later. Many people died of starvation in the vicinity of Strasbourg and we found two dead children in a field of clover where they ate young shoots. "

Alsace is marked in 1817 by an unprecedented wave of emigration, with 5191 emigrants in six months, attributed to the scarcity and occupation by Allied soldiers and their horses, more mouths to feed. (Alsatian Emigration to the United States, 1815-1870)

 

Lecouteur Michel, who studied the aftermath of the eruption of Tambora in its region, reported in an article entitled "Eruption in Indonesia, famine in Normandy"

"After a poor spring, rainy and humid summer of 1816 helped to reduce crop yields, leading to a rise in grain prices, exacerbated by speculation of farmers who had fairly large barns to shelter their crops and their financial reserves to not to hurry to deliver their grain to market, millers, bakers, retail blattiers grain sellers, and other intermediaries.
In autumn 1816 the rising price of wheat is widespread but variable depending on whether or remains in Neufchatel or Forges. If it remains moderate a while in Rouen, it culminates soon in Doudeville and Yvetot.
The manifestations of popular discontent are increasing, especially as factories poach that wool production decreases, causing misery. On the coast, we find that the herring seems to desert the Normandy coast. Fishing, critical resource for many coastal villages, is not good. "The people are suffering," said a police report from November 1816. The sub-prefect appeals to charity, under "the inclemency of the seasons, the stagnation of trade and the fishing defect" Even misery around Saint-Valéry, while in Havre is stressed "the gravity of the situation, the bad harvest and the doldrums of other forms of activity."

{...} It was not until the first quarter of 1818 as the supply of food is sensitive. Prices remained high but confidence had returned, and police action asserted their effectiveness. Rouen, from 16 January, the price of bread was far from 5 cents a pound down to 3 under 3 cents. However, if the situation improved in March, the Attorney General points out: "Many workers are busy, but their salaries have fallen so low that it does not have enough to feed themselves and their families ....
»

 

The Normans health is affected: Dr. Bartholomew Artus Vingtrinier, doctor of Epidemics, notes that in 1817 and 1818 an epidemic affection raged in Le Havre. The symptoms were: "pain in the limbs, loss of strength, precordial anxiety, rumbling, nausea, belching, vomiting materials bilious green or profuse watery diarrhea; intense thirst, dry mouth, bitter scanty urine, burning; most often, happy ending, but long convalescence; members hardly resume their force. ". He said the most likely cause is sudden and frequent alternatives in temperature which took in these two years.

Another doctor, Dr. Lemercier, studied him CBPP outbreak that hit in April 1816 over Lignières-la-Doucelle, a town near Carrouge. "The disease, says Dr. Lemercier in a report dated June 1, 1816, began to show in the town of Lignères about April 15. During this month, the air was alternately wet and dry, high winds blew, the rigors of winter have reappeared in the last fortnight. The contrast of the hot sun and cold and humid atmosphere caused chest inflammations, pleurisy, catarrh, rheumatism, apoplexy ....
On 27 April, when I arrived in the town, there were 40 individuals dead or dying. Are there was a total of 101 people sick, 42 ​​have died.
It was not possible to open the bodies of the dead. "


In a feature story, a letter writer who crossed Burgundy in 1817 noted: "The beggars, many yesterday, are more today. At each relay, a troop of women, children and old men gathered around the car." Another observer, came from the British Isles, remarked, always about Burgundy, that the number of destitute " although important, do attained in any way that those who besiege the traveler in Ireland. "

 

Sources :

  • Global Volcanism Program – Tambora
  • Eruption blog / Eric Klemetti : 194 years since the great Tambora eruption
  • Michel Lecouteur - Eruption en Indonésie, famine en Normandie - Communication personnelle.
  • Grand Québec : 1816, l’année sans été / la disette de 1816 - link
  • La Gazette de Montréal -  An Indonesian volcano made Montreal's summer of 1816 miserable – link 


 

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Publié le par Bernard Duyck
Publié dans : #Eruptions historiques

The "direct" effects of the eruption of 1815 :

It's estimated that thousands of people died from the direct effects in the four months following the eruption.

Important pyroclastic flows, toxic gas clouds, and tsunamis are responsible of the first victims on Sumbawa, about 10,000 people.

With spraying the top of the volcano during the eruption, the erupted volume during the first day is around 150 cubic kilometers of ash, and 25 cubic kilometers of ignimbrites. The ashes are falling up to 1,300 km of Tambora, burying the vegetation of the surrounding islands, and polluting the drinking waters. Acid rain caused by gaseous emanations will kill the few remaining plants and poison the soil for years. Although it is difficult to quantify, it is believed that the resulting famine, to crop failure, will cause the loss of over 80,000 lives. (According to the sources of Zollinger and Raffles)



 

Isopacks of Tambora ash fallout, covering South Sulawesi, Bali, Lombok, East Java and southern Borneo. - The base map was taken from NASA picture and the isopach maps Were traced from Oppenheimer (2003).

Isopacks of Tambora ash fallout, covering South Sulawesi, Bali, Lombok, East Java and southern Borneo. - The base map was taken from NASA picture and the isopach maps Were traced from Oppenheimer (2003).

The writings of the time testify :

«  On my trip towards the western part of the island, I passed through nearly the whole of Dompo and a considerable part of Bima. The extreme misery to which the inhabitants have been reduced is shocking to behold. There were still on the road side the remains of several corpses, and the marks of where many others had been interred: the villages almost entirely deserted and the houses fallen down, the surviving inhabitants having dispersed in search of food ...
Since the eruption, a violent diarrhoea has prevailed in Bima, Dompo, and Sang'ir, which has carried off a great number of people. It is supposed by the natives to have been caused by drinking water which has been impregnated with ashes; and horses have also died, in great numbers, from a similar complaint.
 »

( Lt. Philips, ordered by Sir Stamford Raffles to go to Sumbawa./ cité par Oppenheimer 2003)

Tambora caldera - sulfur gases rise from the caldera - 1988

Tambora caldera - sulfur gases rise from the caldera - 1988

The "Lost Kingdom of Tambora."

Two scientists from the University of Rhode Island are interested there since 1986 : Haraldur Sigurdsson and Steve Carey. In 1988 during an exploration of the caldera, one of their guides speak to them of fragments of pottery and bronze coins found in the jungle, 25 km west of the caldera.

 

2004.08 - Excavation of Tambora - doc.Siggurdsson - Lewis Abrams - Univesity of Rhode Island via AP

2004.08 - Excavation of Tambora - doc.Siggurdsson - Lewis Abrams - Univesity of Rhode Island via AP

The scientists will use a ground-penetrating radar to examine the volcanic deposits of 1815. The excavations, carried out in association with the Indonesian Institute of Volcanology in 2004, appear promising result : in a ravine under 3 meters of ash, traces of an habitation and bronze dishes, ceramic pots were found intact and the rests of a woman charred and wrapped by lava
when she was about to take a glass bottle
, which melted under the heat. The objects have a kinship with those circulating at that time in Vietnam and Cambodia, and show a certain standard of living. Another body is found fixed at the door.

Excavations of Tambora - area bounded by teams from the University of Rhode Island and result of excavations. - A click to view - Photo URI newsExcavations of Tambora - area bounded by teams from the University of Rhode Island and result of excavations. - A click to view - Photo URI news

Excavations of Tambora - area bounded by teams from the University of Rhode Island and result of excavations. - A click to view - Photo URI news

This village, located five kilometers inland, was safe from hackers who controlled the maritime traffic ... and it is likely that its inhabitants were buried and charred by a pyroclastic flow.

Archaeological finds suggest a culture specific to Sumbawa, abruptly and completely swept by the eruption of Tambora 1815. The people were known as merchants in the East Indies; Honey, horses, Sappan wood to produce a red dye, sandalwood for incense and medicines, were the subject of the trade. The decorations found on everyday objects suggest a language related to the Mon-Khmer groups and different from the dialects of Indonesian. The civilization of Sumbawa had also intrigued the Dutch and British explorers in the early 1800s; they were surprised to hear a language spoken nowhere else in Indonesia.

This discovery opens a window in fact over a culture that Sigurdsson do not hesitate to call "The Pompeii of the East".




Roll of strings found in the charred remains of a house - photo Rik Stoetman
 

Skeletons of people of Tambora caught in a pyroclastic flow - a click to enlarge - Images Rik StoetmanSkeletons of people of Tambora caught in a pyroclastic flow - a click to enlarge - Images Rik Stoetman

Skeletons of people of Tambora caught in a pyroclastic flow - a click to enlarge - Images Rik Stoetman

Complete coil of rope within remnants of a collapsed building. - Image Rik Stoetman

Complete coil of rope within remnants of a collapsed building. - Image Rik Stoetman

Sources :

  • Global Volcanism Program – Tambora
  • Scientific American  - April 10, 1815: The Eruption that Shook the World
  • "Plinian and co-ignimbrite tephra fall from the 1815 eruption of Tambora volcano". Bulletin of Volcanology 51 / Sigurdsson, H.; Carey, S. (1983)
  • Nat Geo  - "Lost Kingdom" Discovered on Volcanic Island in Indonesia - link
  • Past Horizons, adventures in archeologia – Lost Kingdom of Tambora - By Rik Stoetman and Dan McLerran. - link

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Publié le par Bernard Duyck
Publié dans : #Eruptions historiques
The eruption of Tambora ...  two hundred years ago -1 - the course of the eruption.

There are two hundred years, Sumbawa, an island in the group of the Lesser Sunda islands in the Indonesian archipelago, was hit by one of the largest eruptions in the modern times ... The Tambora, this large stratovolcano that forms the peninsula Sanggar, entered in eruption after a period of calm that had lasted since the 8th century.

Gunung Tambora caldera - left photo: Bognairadek -  right, photo 03.06.2009 satellite EO-1 NASA - a click to enlarge Gunung Tambora caldera - left photo: Bognairadek -  right, photo 03.06.2009 satellite EO-1 NASA - a click to enlarge

Gunung Tambora caldera - left photo: Bognairadek - right, photo 03.06.2009 satellite EO-1 NASA - a click to enlarge

This eruption will decapitate the volcano : his height pass from 4,300 meters before the cataclysm to 2851 meters, and form a caldera with a diameter of 6 km, 1,250 meters deep.. Described as a rare volcanic explosivity index of 7, it will be about six times more powerful than that of Mount Pinatubo in 1991, or four times that of Krakatoa in 1883. Considered as the deadliest eruption of the last 10,000 years, it have local and global climate impact.
 

The eruption of Tambora ...  two hundred years ago -1 - the course of the eruption.

Before we examine the consequences, see the unfolding of this extraordinary eruption.

The volcano did not wake up without warning ... the activity starts to manifest by earthquakes felt, a year before the eruption, to Australia (Self et al. 1989)

On the evening of April 5, 1815, a short Plinian eruption, accompanied by explosions heard to Makassar on the island of Sulawesi, and Batavia (now Jakarta) on Java, lasts two hours. It propels a plume of ash to 33,000 meters high. On April 6, most numerous explosions are recorded and ashfall reported on Java.

After a few days of relative calm, the second phase of the eruption began on April 10, to 19 hours ... much more powerful. Three pillars of fire rise and merge into 20-21 hours (three vents that will merge to form one) then it is the whole mountain ablaze !  Pumice rain down, some up to 20 cm in diameter, and the ash takes over. This paroxysmal energetic Plinian phase will last very little time and produce an eruptive column of 30-43 km., according to different sources. Towards 22-23 hours, high winds are reported, which may coincide with the collapse of the Plinian column. The successive flows and pyroclastic surges covering the Sanggarr peninsula and destroy the village of Tambora. A tsunami of up to four meters affects most Indonesian islands.

April 11, loud explosions are heard over 2500 km. The ash fall on West Java and Sulawesi. A second tsunami, lower, is noted on Madura, north of Java.

The explosions cease on April 15, but ash cloud continues to surround the volcano until April 23.

Isopacks of Tambora ash fallout, covering South Sulawesi, Bali, Lombok, East Java and southern Borneo. - The base map was taken from NASA picture and the isopach maps were traced from Oppenheimer (2003).

Isopacks of Tambora ash fallout, covering South Sulawesi, Bali, Lombok, East Java and southern Borneo. - The base map was taken from NASA picture and the isopach maps were traced from Oppenheimer (2003).

Stratigraphy of the deposits from the eruption of Tambora in 1815 - doc.Sigurdsson "Lost Kingdom of Tambora" / Armstrong Sompotan.

Stratigraphy of the deposits from the eruption of Tambora in 1815 - doc.Sigurdsson "Lost Kingdom of Tambora" / Armstrong Sompotan.

During 2 to 3 days, the darkness is total within 600 km. accompanied by tropospheric cloud of an air pocket hot at first, then very cold, as reported to Banjuwangi, at 400 km. of the volcano. These cold temperatures were recorded in India, two weeks later.

The erupting volume is estimated of 160 cubic kilometers of ejected trachy-andesitic pyroclastic materials. To better capture the volume, ash statements in Makassar / Sulawesi had a density of 636 kg / m². Near the volcano, the thickness of the deposits reached thirty meters.

Ash cover of at least 1 cm. an area of ​​500,000 km², and their extension depends on monsoon winds blowing then from east to west (550 km. to the west, 400 km. to the north and 100 km. to the east).

At sea, the rafts of pumice and ash agglomerates, reach up to 1 m. thick on several kilometers wide, and will hinder the navigation during several years.

Ash and gas reached the stratosphere : the coarser ash particles begin to fall within 1 to 2 weeks, but the finer remain several months to several years in the atmosphere at an altitude of between 10 and 30 km .

The number of victims depends on the sources: in addition to 10,000 direct victims of  pyroclastic flows, it is estimated that on Sumbawa, 38,000 people died of deprivation and 10,000 on Lombok (Zollinger 1855). Another source gives 48,000 and 44,000 deaths respectively on Sumbawa and Lombok (Petreschevsky 1949). Additional victims number in Bali and East Java because of the famine. Oppenheimer change the total number of victims in 2003: at least 71,000  !

Portrait of Sir Thomas Stamford and cover of his book "The history of Java" - a click to openPortrait of Sir Thomas Stamford and cover of his book "The history of Java" - a click to open

Portrait of Sir Thomas Stamford and cover of his book "The history of Java" - a click to open

An historical report :

Only a good year after the eruption, a detailed report of the disaster is published by Sir Thomas Stamford, naturalist and English governor of Indonesia, in his "History of Java" (1817). It will be incorporated in the "Principles of Geology" of Lyell in 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.

The eruption of Tambora ...  two hundred years ago -1 - the course of the eruption.

“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.

 

Sources :

  • Global Volcanism Program – Tambora
  • Scientific American  - April 10, 1815: The Eruption that Shook the World
  • Eruption blog / Eric Klemetti : 194 years since the great Tambora eruption
  • "Plinian and co-ignimbrite tephra fall from the 1815 eruption of Tambora volcano". Bulletin of Volcanology 51 / Sigurdsson, H.; Carey, S. (1983)
  • Self, S. et al., 1984, Volcanological study of the great Tambora eruption of 1815,Geology; v. 12, no. 11, p. 659-663
  • World Drizzles - "The History of Java" –Thomas Stamford Raffles

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Based on satellite imagery, the VAAC Tokyo reported on November 20, 2013 / 7:17 UTC that a surtseyan eruption starts (from an estimated depth of -50 m), feeding a plume from a height of 600 meters, emerging about 500 meters south of Nishino-shima.

On 21 November, the Japan Coast Guards / JCG and the Japan Meteorological Agency / JMA notes that the "new island" is 200 meters in diameter. Photos show the plume and ash / rocks forcefully expelled from the crater.




 

Cypressoïde plume and water vapor off the Nishino-shima volcano on 11/20/2013 - hydromagmatic phase of the surtseyan eruption - photoGetty pictures

Cypressoïde plume and water vapor off the Nishino-shima volcano on 11/20/2013 - hydromagmatic phase of the surtseyan eruption - photoGetty pictures

Nishino-shima and the site of the eruption November 20, 2013 - photo Japan Coast Guards

Nishino-shima and the site of the eruption November 20, 2013 - photo Japan Coast Guards

 Nishino-shima, the 11/21/2013 - formation of a tuff / scoria cone - projections of bombs and gas / ash /steam plume - photo Japan Coast Guards via Japan Daily Press

Nishino-shima, the 11/21/2013 - formation of a tuff / scoria cone - projections of bombs and gas / ash /steam plume - photo Japan Coast Guards via Japan Daily Press

From November 24, the Coast Guard reported that the lava comes out of the crater.

The island continues to build in December so that the 24.12, only a small channel separates the new Niijima of Nishino-shima, filled with water discolored in orange. On the map of expansion by the JCG, we can see how the island has increased between 13 and 24 December 2013.

Nishino-shima - The 24/11/2013, aerial phase of the eruption: the strombolian explosive activity accompanied by a plume of ash and lava - photo Japan Coast Guards

Nishino-shima - The 24/11/2013, aerial phase of the eruption: the strombolian explosive activity accompanied by a plume of ash and lava - photo Japan Coast Guards

3D views of Nishino-shima - the tip of the volcano is in green bronze - doc MLIT - a click to enlarge3D views of Nishino-shima - the tip of the volcano is in green bronze - doc MLIT - a click to enlarge

3D views of Nishino-shima - the tip of the volcano is in green bronze - doc MLIT - a click to enlarge

Progression of the new island between November and 12/21/2013 - photo Kyodo / AP

Progression of the new island between November and 12/21/2013 - photo Kyodo / AP

Nishino-shima, left, separated from Niijima, right, through a narrow channel - Territorial fusion is coming, and the appellation "volcano" could be changed to "adventitious cone" - 12.24.2013 / JCG.

Nishino-shima, left, separated from Niijima, right, through a narrow channel - Territorial fusion is coming, and the appellation "volcano" could be changed to "adventitious cone" - 12.24.2013 / JCG.

Map of the progression of lava flows and the extension of the new island, between November 20 and December 26, 2013 - Doc JCG

Map of the progression of lava flows and the extension of the new island, between November 20 and December 26, 2013 - Doc JCG

On December 26, 2013, the Japan Coast Guard confirms that the two islands are joined. The closure by coalescence of the lava flows left a small lake, of temporary existence, which eventually disappear through evaporation. As the new island merged with the former, it will again name Nishinoshima.
December 26, 2013, Niijima joined Nishino-shima - photo JCG

 

December 26, 2013, Niijima joined Nishino-shima - photo JCG

December 26, 2013, Niijima joined Nishino-shima - photo JCG

An aerial inspection by the Geological Survey of Japan on February 28, 2014 shows emissions of gas and steam at the two cones of the last eruption.The flows in all directions reach the sea to the east, south-southeast and west-northwest.

Situation on 16 February 2014,  lava is flowing in all directions - Doc. Japan Coast Guards

Situation on 16 February 2014, lava is flowing in all directions - Doc. Japan Coast Guards

Nishino-shima: 28/02/2014 Inspection by the Geological Survey of Japan

Nishino-shima: 28/02/2014 Inspection by the Geological Survey of Japan

Nishino-shima: 28/02/2014 Inspection by the Geological Survey of Japan - the two cones are degasing and a small lake, imprisoned by lava flows joining, is in evaporation phase.

Nishino-shima: 28/02/2014 Inspection by the Geological Survey of Japan - the two cones are degasing and a small lake, imprisoned by lava flows joining, is in evaporation phase.

After a period of lava flows in all directions, the active craters, at the number of 3 in August, continues to spit lava at a rate of 200,000 cubic meters each day ... and lava accumulates mainly eastward.

Nishino-shima on 03/06/2014 - photo JCG / AIST

Nishino-shima on 03/06/2014 - photo JCG / AIST

Evolution between December 4, 2013 and July 4, 2014 - Doc Arukazan.jp

Evolution between December 4, 2013 and July 4, 2014 - Doc Arukazan.jp

 Nishino-shima on 08/26/2014 - photo JCG

Nishino-shima on 08/26/2014 - photo JCG

 Map the extension of cast between November 22, 2013 and August 12, 2014 - Doc. eri.u-tokyo

Map the extension of cast between November 22, 2013 and August 12, 2014 - Doc. eri.u-tokyo

Uncertainties are issued by scientists about the stability of the building, and the risk of flank collapse, current volcanic islands is concerned.

Nishinoshima - evolution and distribution of lava flows - On the cross section,  you can see an accumulation of the lava flows to the east (right side of the diagram) - doc eri.u-tokyo

Nishinoshima - evolution and distribution of lava flows - On the cross section, you can see an accumulation of the lava flows to the east (right side of the diagram) - doc eri.u-tokyo

The lava flows will then move towards the northeast and in September, to the north and west ... engulfing the former island of which remain only a thin plot.

The Coast Guard measured (on aerial photos) the area of the island, which reached 1.89 km² on October 16, nearly nine times the size of the volcano had the first time he was seen.

For Professor Setsuya Nakada, a volcanologist of the Seismic Research Institute of the University of Tokyo, "the eruption will last a few years."

 

Nishino-shima: the 16/10/2014, the lava almost entirely covered the former island - photo JCG

Nishino-shima: the 16/10/2014, the lava almost entirely covered the former island - photo JCG

Nishino-shima: the rest of the former island and the active cone, the 11/15/2014 - Mainichi Photo

Nishino-shima: the rest of the former island and the active cone, the 11/15/2014 - Mainichi Photo

Sources:
- Japan Coast Guard
- Geological Survey of Japan
- Japanese media

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St. Helens - explosion in the crater on October 1, 2004 / 12:16 PDT. - Photo John Pallister / USGS

St. Helens - explosion in the crater on October 1, 2004 / 12:16 PDT. - Photo John Pallister / USGS

In late September, an anniversary at St. Helens : the resumption of the volcanic activity after the eruptive crisis of 1980-1986.

On September 23, 2004, after four years of "seismic calm," a swarm of small-magnitude and shallow earthquakes begins under the lava dome that has formed in 80-86.

Seismicity will increase, until it opens on October 1, 2004 on a series of explosions associated with ash plumes, starting from a vent located on the SW edge of the old dome. A quieter stage follows next.



 

Cracks in the Crater Glacier S. Helens on 2.10.2004 following the consecutive inflation due to the new activity - photo Mike Poland / USGS

Cracks in the Crater Glacier S. Helens on 2.10.2004 following the consecutive inflation due to the new activity - photo Mike Poland / USGS

Photogeological map of the crater of St. Helens on 29.11.2004 - different new domes in late November and their position relative to the dome 1980-86. Note that the new dome bisects the Crater Glacier, now called East and West Glacier - Doc John Pallister / USGS

Photogeological map of the crater of St. Helens on 29.11.2004 - different new domes in late November and their position relative to the dome 1980-86. Note that the new dome bisects the Crater Glacier, now called East and West Glacier - Doc John Pallister / USGS

On October 11, a new phase of construction of the dome begins with  hot lava hardened spines that dot the surface of the glacier. These successive spines will accumulate for three years to form the new dome with a height of 460 meters.

Lava spines characterize peleans type domes, surmounted by protrusions or "needles". (classification Blake 1990 / in Bardintzeff 1998)

Between 2004 and 2008, the growth of the dome is made, not by effusion, but by a continuous extrusion of lava spines, strongly degassing.

The volume of extruded lava onto the crater floor is estimated at almost 92 million cubic meters.

 

St. Helens crater - the needle 27.10.2004 - USGS Photo

St. Helens crater - the needle 27.10.2004 - USGS Photo

St. Helens crater - the new dome and the spine (in the foreground )  27.05.2005 - photo JHScurlock / USGS

St. Helens crater - the new dome and the spine (in the foreground ) 27.05.2005 - photo JHScurlock / USGS

 The dome in the crater of St. Helens as seen from the north 10.08.2005 - USGS Photo

The dome in the crater of St. Helens as seen from the north 10.08.2005 - USGS Photo

St. Helens - Panoramic from south crater rim on 27.07.2006 - photo and annotations Willie Scott / USGS

St. Helens - Panoramic from south crater rim on 27.07.2006 - photo and annotations Willie Scott / USGS

St. Helens - the new dome and her spine, that cut the Crater Glacier into two - the 05.10.2006 - USGS Photo

St. Helens - the new dome and her spine, that cut the Crater Glacier into two - the 05.10.2006 - USGS Photo

 St. Helens - the new dome seen from the north 30.05.2008 - USGS Photo

St. Helens - the new dome seen from the north 30.05.2008 - USGS Photo

The period 2004-2008 was only marked by two major explosions, the first January 16, 2005, without notables warning signs. The second takes place on March 8, 2005, after a "subtle" increasing of the seismicity in the previous hours.
 

Plume from the explosion of March 8, 2005 - photo USGS

Plume from the explosion of March 8, 2005 - photo USGS

Sources :

- USGS Volcano hazards program : St Helens 2004-2008 renewed volcanic activity

- photos d'archives USGS / Cascade volcano observatory.

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The eruption of the Capelinhos 1957-1958:

After 12 days of earthquakes, on September 23, 1957, around 6:30, the sea surface begins to boil, and vapors are emitted one kilometer NW of the lighthouse.
Three days later, the activity increases: black ash and steam are emitted off the coast.

On 27 September, at 6:45, a submarine eruption begins 300 meters from Ponta dos Capelinhos. A cloud of mud, solid fragments and gas amounts to about 1,000 meters, and reach an area of 1,200 meters around. The surrounding buildings undergo their first damage: broken windows, tiles falling from roofs. The next day, the ashes cover the extreme west of the island of Faial, requiring the evacuation of Norte Pequeno and Canto.

Faial - Initial phase of the eruption of Capelinhos 1957 - José Agostinho Espolio do TC-Museu de Angra do Heroismo / Siaram.

Faial - Initial phase of the eruption of Capelinhos 1957 - José Agostinho Espolio do TC-Museu de Angra do Heroismo / Siaram.

Faial - Eruption Capelinhos 1957 - plume and base surges; scale is given by the lighthouse in the foreground - do Espolio TC José Agostinho-Museu de Angra do Heroismo / Siaram

Faial - Eruption Capelinhos 1957 - plume and base surges; scale is given by the lighthouse in the foreground - do Espolio TC José Agostinho-Museu de Angra do Heroismo / Siaram

 Faial - Capelinhos eruption, the plume in 1957 - photo Sailfeed.

Faial - Capelinhos eruption, the plume in 1957 - photo Sailfeed.

The Surtseyan phase will last seven months and a half : big explosions, accompanied by gas and black ashes cypressoïdes plume, will succeed, and formed from 10 October an island named Ilha Nova, The eruption will experience periods of high activity, alternating with other more quiet ... October 29, the island reached a diameter of 800 meters and a height of 99 meters. It will disappear into the sea on October 30.

In November, the frequent ash emissions will create new islands that will unite to form an isthmus linking to Faial.

Capelinhos eruption plume cypressoïde and training Ilha Nova - photo Nova casa portuguesa

Capelinhos eruption plume cypressoïde and training Ilha Nova - photo Nova casa portuguesa

Capelinhos eruption plume cypressoïde and building of  Ilha Nova - photo Radiopico.

Capelinhos eruption plume cypressoïde and building of Ilha Nova - photo Radiopico.

Mid-December, began an transient subaerial effusive phase . A fault opens on the eastern part of the cone, where seven streams of lava amount to 10 -15 meters high arise. Then the activity focuses on three fireplaces with Strombolian explosions at short intervals.

From May to October 1958, the volcano in a subaerial phase with Strombolian characteristics. The passage of the underwater phase to the land phase is marked by a seismic crisis in the night of 12 to 13 may, during which 450 aftershocks recorded. The eruption has periods of high explosivity, accompanied by projections of incandescent lava fragments more than 500 meters in height, interspersed with episodes of effusive character, and the emission of lava flows of variable viscosity.

The eruption is weakening from September 58, and a last emission of lava is observed on October 24. After thirteen months of operation, the main cone is 160 meters high; the total volume of material emitted, lava flows and tephra of olivine basalt, is 174 million cubic meters ... the island grew from 2.4 km ².

Left, Map of Capelinhos deposits - doc. Bulletin of Volcanology - Capelinhos 1957-1958, Faial, Azores: deposits Formed by an emergent surtseyan eruption - by PDCole et al. - Right, retrospective in pictures - a click to enlarge.Left, Map of Capelinhos deposits - doc. Bulletin of Volcanology - Capelinhos 1957-1958, Faial, Azores: deposits Formed by an emergent surtseyan eruption - by PDCole et al. - Right, retrospective in pictures - a click to enlarge.

Left, Map of Capelinhos deposits - doc. Bulletin of Volcanology - Capelinhos 1957-1958, Faial, Azores: deposits Formed by an emergent surtseyan eruption - by PDCole et al. - Right, retrospective in pictures - a click to enlarge.

The damage is significant on neighboring villages, Capelo, Praia do Norte and Cedros; cultivated fields are covered with a thick layer of ash, but no victims.

The affected people are forced to migrate, significant between 1957 and 1960. The Azorean Refugee Act of September 2, 1958, authorized the emigration of 1,500 people in the United States.

The village of Capelo after the eruption - photo A soma dos dias.

The village of Capelo after the eruption - photo A soma dos dias.

 Faial - a house roof collapsed under the weight of ash - photo A soma dos dias.

Faial - a house roof collapsed under the weight of ash - photo A soma dos dias.

Since then, the costal erosion reduces cone ... in the sixties, ten meters flanks of the volcano are lost each year in the Atlantic Ocean.

Faial - Vulcão dos Capelinhos - the lighthouse brand the old shoreline - a spatter cone was erected in the tuff cone - Geoparque Azores

Faial - Vulcão dos Capelinhos - the lighthouse brand the old shoreline - a spatter cone was erected in the tuff cone - Geoparque Azores

Faial - Vulcão dos Capelinhos - The ignimbrite layers are exposed by erosion - Geoparque Azores

Faial - Vulcão dos Capelinhos - The ignimbrite layers are exposed by erosion - Geoparque Azores

Faial - Vulcão dos Capelinhos - NO tip eroded - layers of lava and dykes (bluish) among the red ash - photo courtesy of Marco Fulle / Stromboli on line

Faial - Vulcão dos Capelinhos - NO tip eroded - layers of lava and dykes (bluish) among the red ash - photo courtesy of Marco Fulle / Stromboli on line

  For volcanophilatélistes - commemorative stamps 50th anniversary of the eruption  For volcanophilatélistes - commemorative stamps 50th anniversary of the eruption

For volcanophilatélistes - commemorative stamps 50th anniversary of the eruption

Sources :

- Bulletin of Volcanology - Capelinhos 1957–1958, Faial, Azores: deposits formed by an emergent surtseyan eruption – by P.D.Cole & al.

- The Capelinhos Eruption: Window of Opportunity for Azorean Emigration

- A soma dos dias - link

- Stromboli on line – Azores - Surtsey-like Cones on Faial (September 2009) - link

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Japanese and Salvadorans anthropologists found three skeletons, dating from 1,600 years, in the site of Nueva Esperanza, located 70 kilometers southeast of the capital San Salvador.

The bones match those of two adults 25 to 35 years, and a child from 7 to 9 years old, in good condition. Two of them are sitting with crossed legs, similar to the position of remains found on archaeological sites in Guatemala, Kaminaljuyú and in Mexico, Teotihuacan, both centers of power in pre-Columbian Mesoamerica.

The skeletons were discovered under a layer of volcanic ash about two meters thick, which allowed a good storage.

 

Nueva Esperanza - the bones in volcanic ash - photo Agencias / Ciencia y Tecnologia through Emol

Nueva Esperanza - the bones in volcanic ash - photo Agencias / Ciencia y Tecnologia through Emol

Region Nueva Esperanza was covered by ash gigantic eruptions of the volcano Ilopango between the 5 and 6th centuries, which led to the conservation of prehispanic archaeological evidence of a pueblo, probably living fishing and salt production.

Left, presentation of burial by Akira Ichikawa, a Japanese archaeologist - photo KPMR News - right, excavations - Photo AFP / ChinaPost Left, presentation of burial by Akira Ichikawa, a Japanese archaeologist - photo KPMR News - right, excavations - Photo AFP / ChinaPost

Left, presentation of burial by Akira Ichikawa, a Japanese archaeologist - photo KPMR News - right, excavations - Photo AFP / ChinaPost

Ilopango caldera :

Ilopango caldera, 11 km.on 8, is occupied by one of the largest lake in Salvador, 72 km ².  It is under the control of regional faults of Salvadoran central graben. Four major explosive eruptions, of rhyolitic-dacito nature, are reported from the late Pleistocene to Holocene, accompanied by pyroclastic flows and deposits that covered the country.

The final collapse, which produced the current caldera results from the eruption Terra Blanca Joven / TBJ, which devastated the Mayan cities.

The caldera and Lake Ilopango - photo Nasa

The caldera and Lake Ilopango - photo Nasa

Lago de Ilopango and Volcán Chinchontepec - Photo Mauro Arias

Lago de Ilopango and Volcán Chinchontepec - Photo Mauro Arias

According to Robert A. Dull, University of Texas at Austin, the TBJ eruption would produce 84 km ³ of tephra (revised volume based on TBJ deposits found in Nicaragua and offshore), twenty times more than the St Helens eruption in 1980. Its volcanic explosivity index  and dating were reviewed respectively VEI 6.9 (about the eruption of Tambora in 1815) and between 526 and 536 years.

This Plinian eruption and deadly pyroclastic flows accompanying could explain "the hiatus Maya", a collapse affecting the Mayan society in the southern Lowlands at the end of the Preclassic period.

It would also be involved in the overall cooling of years 535-536, 18 months of covered sky, poor harvests and famine, described by Roman and Chinese
historians.

Deposits of Tierra Blanca Joven eruption in a quarry near Cojutepeque, 9 km ENE of the Ilopango caldera - Photo Giuseppina Kysar, 1999 (Smithsonian Institution)

Deposits of Tierra Blanca Joven eruption in a quarry near Cojutepeque, 9 km ENE of the Ilopango caldera - Photo Giuseppina Kysar, 1999 (Smithsonian Institution)

Sources :

- KPMR News - Descubren tres osamentas de al menos 1.600 años de antigüedad en El Salvador – 07.04.2014 - link

- Emol – Cinecia y Tecnologia - El Salvador: Hallan osamentas humanas de 1.600 años bajo las cenizas de un volcán – link

- Global Volcanism Program - Ilopango

- Historica - Volcán de los Cerros Quemados. – link

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