The eruption of Samalas in 1257 is a major volcanic event of the Middle Ages , the consequences of which had a strong impact on the Earth. The existence of a major eruption ( volcanic explosivity index 7) on that date was first attested by the paleoclimatology (several unusually cold years) and traces of sulfates recorded in ice cores as well in Arctic in Antarctica , on the same date, confirming the global scale of the event 1. An interdisciplinary work (involving field geology and the exegesis of Indonesian manuscripts) made it possible in the 2010s to identify the volcano involved.
Traces in the ice cores
The ice caps are a unique source of information about the planet’s past: each winter, a layer of ice is added to the top of the cap, trapping air bubbles. By analyzing the air trapped in the ice, one can thus reconstruct very precise time series on the composition of the atmosphere over the past centuries. The Greenland Ice Sheet Project is an international project ( US , Denmark , Switzerland ) to take the harp of ice cores and use the information. The drilling begins in 1971 2 .
The measurement of sulfate over 2000 years shows peaks corresponding to volcanic eruptions: eruptions historically well known as that of Vesuvius in 79 or that of Tambora in 1815 , the plume reaches the stratosphere , are in the measurement. However other peaks do not correspond to any known eruption, and this is the case of the most important of all, located in the late 1250s. However, the measure in Greenland alone does not allow to determine if the we are dealing with an eruption of planetary importance, or a more modest event but located near the place of measurement. A few years later, similar measures in Antarcticashow a peak at the same time, reinforcing the idea of a rash that impacted the planet (although the assumption of simultaneous events in both polar regions can not be ruled out completely) 1 .
In the early 1990s , the comparison between the volcanic ash (also trapped in the ice) collected in both polar regions shows a great similarity in appearance and Geochemistry , confirming a common origin. Moreover, the fallout is about the same amplitude in the two polar areas, which points to a volcano located in the intertropical zone 3 .
The volcanologists have researched for thirty years volcanoes candidates to the eruption proved by circumstantial evidence 4 . In 2000, the date of the eruption and the magnitude of its consequences are well identified, but its location remains a mystery, several volcanoes like El Chichón in Mexico , the Quilotoa in Ecuador and a Saudi volcano have been implicated 5 , 6 . El Chichón attracted a lot of intention: his geochemistry seemed to correspond to the ashes found in the ice, he had a sulfur emitting eruption in 1982and traces of an eruption around 1250 were found. However, the study on the site showed that this eruption was much too small to explain the observed sulfate peak, with an estimated VEI 4 7 , 6 .
At the beginning of the 2010s, French (Franck Lavigne, Paris 1 ) and Indonesian teams reviewed dozens of little-studied volcanoes in the Indonesian archipelago in search of traces of a corresponding eruption. Their work helped to identify almost certainly the eruption of 1257 with a caldera present on the island of Lombok near Bali , the Segara Anak Caldeira . The site is of a size compatible with the scale of the event 1257. The Carbon dating 14 twenty-one samples of trees buried in the pyroclastic deposits is perfectly consistent with an eruption in 1257 6. The last doubts were raised with the geochemical identification of the ash to those found in the ice cores, and the modeling of the volcano which allowed to evaluate the volume of ejecta in the range 33-40 km³, consistent with the evaluations based on measurements of ice cores 8 .
The study of an ancient Javanese manuscript , Babad Lombok ( babad meaning ” Chronicle “) written on palm leaves and kept at the National Museum of Indonesia in Jakarta , provided historical evidence of the event, and put a local name on the volcano: the Samalas . This narrative indicates that a city named Pamatan, which was the capital of Lombok Kingdom (on which there is virtually no other source), was buried during the eruption by what evokes fiery clouds . of excavationson the site could thus give rise to a major archaeological discovery that has been compared to an ” Asian Pompeii ” 6 , 9 .
Sequence of the eruption
The Samalas culminated at about 4,200 meters above sea level and was 8 to 9 kilometers in diameter 10 , 6 . This cone had formed “well before 12,000 BC. AD “. The “new” Rinjani , much more recent, which still flanked the old volcano east 11 .
The original volcano disappeared during the eruption. The gas pressure in the magma chamber caused the eruption of the volcano. In this type of volcano ( gray volcano ), the lava is too viscous to be evacuated easily, but a riser eventually establishes itself. The magma chamber is depressurized, and the whole edifice collapses on itself, forming a huge crater of 6 km by 8.
The eruption would have produced a volcanic plume reaching 43 kilometers altitude 10 . With a volcanic explosive index of 7, it is called “mega-colossal” and seems to have been the most violent of the last 10,000 years 12 . Of volcanic clouds have descended the slopes of the mountain, a distance of 25 km to the coast in three directions, leaving up to 35 meters of pyroclastic deposits 6 , 10 .
The caldera resulting from the eruption was then filled with water. The level of the lake is 2000 meters above sea level. Three smaller volcanic cones have formed in the caldera 11 . One of them, Barujari , is always very active.
In a publication in 2017, a Chinese team found in sediment lake on one of the Paracel islands traces of volcanic material likely coming from Samalas 13
Consequences of the eruption
The eruption has undoubtedly devastated, and made partially uninhabitable for decades, the island of Lombok, as well as Bali and western Sumbawa . The king Javanese Kertanagara annexed in 1284 the island of Bali to his own kingdom, without encountering strong resistance. This could be explained by the fact that the island has been permanently depopulated and disorganized by the eruption 6 .
The Samalas eruption has caused, according to a recent study based on geochemical traces, the most important release of gas (notably sulfur dioxide and chlorine gases ) in the stratosphere of the common era , before the eruption of Tambora in 1815. , much better documented. The release is estimated at 158 million tonnes of sulfur dioxide, 227 million tonnes of chlorine, and 1.3 million tonnes of bromine 14 Such a release of gas has a significant effect on climate, through a phenomenon known as global darkening name .
Thus, the years immediately following the eruption were colder than normal in many parts of the world. This cold period, evidenced both by paleoclimatic traces such as dendrochronology 15 , 16 and by direct historical evidence, led to poor harvests.
Thus England suffered a serious famine in 1258, and some researchers now make a connection with the eruption. This episode is related in the Chronica Majora 17 . A common grave containing 10 to 15,000 skeletons was discovered in the eastern part of London in the late 1990s . First attributed to the Great Plague , it eventually turned out to have been built for the victims of the 1258-59 famine. The population of London at the time was around 50 000, which gives an idea of the scale of human losses 18 .
Abnormally high food prices have also been reported in several European countries, causing social unrest and perhaps the emergence of the flagellants’ movement in Italy 5 . In Japan , the Azuma Kagami reports a cold and rainy summer and poor harvests causing starvation 16 .
However, a research article published in January 2017 16 relativizes this effect on the climate, noting that North America does not seem to have been affected by this cooling and suggests that the food situation in England and Japan was already difficult before the eruption, which would have only aggravated an existing crisis.
Link with the Little Ice Age
A question that remains to be debated is whether this effect on the climate was only transient or whether the eruption was a cause of the switch from the medieval climatic optimum to the Little Ice Age 14 . If the direct effect of aerosols on the climate is brief, because they are rapidly disappearing from the atmosphere, volcanic winter may have triggered feedbacks (changes in ocean currents , progression of ice-covered surfaces) with long-term influence on the climate. Recent modeling work 19 of the transition to the Little Ice Age incorporates volcanic forcing (including the eruption of samalas, but that of Kuwaeparticular) among the causes taken into account. The experience of one-to-one removal of model forcings (volcanoes, changes in Earth’s orbit, variation of greenhouse gases, and variation in solar radiation) shows a significant influence of volcanism.
- ↑ a and b ( in ) Clive Oppenheimer , ” Ice core and palaeoclimatic evidence for the timing and nature of the great mid-13th century volcanic eruption ” , International Journal of Climatology , vol. 23, n o 4,, p. 417-426 ( ISSN 0899-8418 , DOI 10.1002 / joc.891 )
- ↑ ” Ice Core ” [ archive ] (accessed November 27, 2017 )
- ↑ ( in ) JM Palace , S. Germani and GA Zielinski , ” Inter-hemispheric transport of Volcanic Ash from a 1259 AD Volcanic Eruption to the Greenland and Antarctic Ice Sheets ” , Geophysical Research Letters , vol. 19, n o 8,, p. 801-804 ( ISSN 0094-8276 , DOI 10.1029 / 92GL00240 ).
- ↑ ” Investigation on the eruption that marked the Middle Ages ” [ archive ] , on CNRS The newspaper (accessed November 19, 2017 )
- ↑ a and b ( in ) Richard B. Stothers , ” Climatic and Demographic Consequences of the Massive Volcanic Eruption of 1258 ” , Climatic Change , vol. 45, n o 2, p. 361-374 ( ISSN 0165-0009 , DOI 10.1023 / A: 1005523330643 ).
- ↑ a , b , c , d , e , f and g ( en ) Franck Lavigne , Jean-Philippe Degeaia , Jean-Christophe Komorowski , Sebastien Guillet , Vincent Robert , Pierre Lahitte , Clive Oppenheimer , Markus Stoffeld , Céline M. Vidal , Surono , Indyo Pratomo Patrick Wassmera , Irka Hajdas , Danang Sri Hadmokoland Edward Belizal of , ” Source of the great AD 1257 eruption mystery unveiled, Samalas volcano, Rinjani Volcanic Complex, Indonesia ” , International Journal of Climatology , vol. 23, n o 4,, p. 16742-16747 ( ISSN 0899-8418 , DOI 10.1073 / pnas.1307520110 , read online [ archive ] ).
- ↑ ( in ) CAM Nooren, ” Tephrochronological evidence for the Late Holocene eruption of El Chichon volcano history, Mexico ” , Geofísica internacional , vol. 48, n o 1, ( ISSN 0016-7169 , read online [ archive ] ).
- ↑ ( in ) Celine Vidal , ” Dynamics of the Major Plinian eruption of Samalas in 1257 AD (Lombok, Indonesia) ” , Bulletin of Volcanology , Springer Berlin Heidelberg flight. 77, n o 9,, p. 73 ( ISSN 1432-0819 , DOI 10.1007 / s00445-015-0960-9 , summary [ archive ] ,read online [ archive ] )
- ↑ ( in ) Robin Wylie, ” Volcano Monster Detectives Uncover Ancient Eruption (Op-Ed) ” [ archive ] , on livescience.com , (accessed November 20, 2017 ) .
- ↑ a , b and c ” The mystery of the greatest volcanic eruption of the last millennium is solved “, Le Monde , ( read online [ archive ] )
- ↑ a and b ( in ) Heryadi Rachmat , ” Petrogenesis of Rinjani Post-1257-Caldera-Forming-Eruption Lava Flows ” , INDONESIAN NEWSPAPER ON GEOSCIENCE , vol. 3, n o 2
- ↑ ” Eruption of volcano Samalas ” [ archive ] , on ipgp.fr (accessed 25 December 2016 )
- ↑ ( in ) Li Kuang Sun , ” A great volcanic eruption around AD 1300 Recorded in lacustrine sediment from Dongdao Island, South China Sea ” , Journal of Earth System Science , Springer India flight. 126, n o 1,, p. 7 ( ISSN 0973-774X , DOI 10.1007 / s12040-016-0790-y ,summary [ archive ] , read online [ archive ] )
- ↑ a and b ( in ) Céline M. Vidal , Nicole Métrich , Jean-Christophe Komorowski , Indyo Pratomo , Agnes Michel , Nugraha Kartadinata and Vincent Robert , ” The 1257 Samalas eruption (Lombok, Indonesia): the single greatest stratospheric gas release of the Common Era ” , Scientific Reports , vol. 6, n o 1, ( ISSN 2045-2322 , DOI 10.1038 / srep34868 ).
- ↑ ( in ) F. Gennaretti , D. Arseneault , A. Nichol , L. Perreault and Y. Begin , ” Volcano-induced shifts in diet millennial tree-ring chronologies from northeastern North America ” , Proceedings of the National Academy of Sciences , flight. 111, n o 28,, p. 10077-10082 ( ISSN 0027-8424 , DOI 10.1073 / pnas.1324220111 )
- ↑ a , b and c ( in ) Sébastien Guillet , Christophe Corona , Markus Stoffel , Myriam Khodri Franck Lavigne , Pablo Ortega and Nicolas Eckert , ” Climate response to the Samalas volcanic eruption in 1257 Revealed by proxy records ” , Nature Geoscience , vol . 10, n o 2, p. 123-128 ( ISSN 1752-0894 , DOI 10.1038 / ngeo2875 ).
- ↑ ( in ) Bruce MS Campbell , ” GLOBAL CLIMATES, THE 1257 MEGA-ERUPTION OF SAMALAS VOLCANO, INDONESIA, AND THE ENGLISH FOOD CRISIS OF 1258 ” , Transactions of the Royal Historical Society , vol. 27, p. 87-121 ( ISSN 0080-4401 , DOI 10.1017 / S0080440117000056 ).
- ↑ Dalya Alberge, ” Mass grave in London reveals how volcano caused global disaster ” [ archive ] , on The Guardian , (accessed December 4, 2017 )
- ↑ ( in ) Heather J. Andres and WR Peltier , ” Regional Influences of Natural External forcings on the Transition from the Medieval Climate Anomaly to the Little Ice Age ” , Journal of Climate , vol. 29, n o 16,, p. 5779-5800 ( ISSN 0894-8755 , DOI 10.1175 / JCLI-D-15-0599.1 ).