Laki eruption, Iceland

Transcription

1 Laki eruption, Iceland Eruption History and Atmospheric Effects Thor Thordarson Faculty of Earth sciences, University of Iceland 12/8/2017 1

2 Outline Atmospheric Effects of the Laki Eruption in Iceland Volcano-Climate interactions - background Laki eruption Eruption history Sulfur release and aerosol loading Plume transport and aerosol dispersal Environmental and climatic effects Concluding Remarks 12/8/2017 2

3 Santorini, 1628 BC Etna, 44 BC Tambora, 1815 Lakagígar, 1783 Toba, 71,000 BP Famous Volcanic Eruptions Krakatau, 1883 Pinatubo, 1991 El Chichón, 1982 St. Helens, 1980 Agung, 1963

4 Major volcanic eruptions of the past 250 years Volcano Year VEI d.v.i/e max IVI Lakagígar [Laki craters], Iceland Unknown (El Chichón?) Tambora, Sumbawa, Indonesia Cosiguina, Nicaragua Askja, Iceland * Krakatau, Indonesia Okataina [Tarawera], North Island, NZ Santa Maria, Guatemala Ksudach, Kamchatka, Russia Novarupta [Katmai], Alaska, US Agung, Bali, Indonesia Mt. St. Helens, Washington, US El Chichón, Chiapas, Mexico Mt. Pinatubo, Luzon, Philippines

5 Volcano Climate Interactions Key to Volcanic Forcing is: SO 2 mass loading, eruption duration plume height replenishment aerosol production, residence time 12/8/2017 5

6 Volcanic Forcing: sulfur dioxide sulfate aerosols SO 2 75%H 2 SO %H 2 O clear sky 1991 Pinatubo aerosols 12/8/2017 6

7 Stratospheric aerosols (Lifetime 1-3 years) H 2 S H SO 2 SO 4 2 CO 2 absorption (near IR) forward scatter backscatter More Reflected Solar Flux Solar Heating dynamic effect IR Heating absorption (IR) Less Upward IR Flux emission emission IR Cooling N 2 H 2 O Ash Reduced Direct Flux Enhanced Diffuse Flux SO 2 H 2 SO 4 Tropospheric aerosols (Lifetime 1-3 weeks) Less Total Solar Flux More Downward IR Flux radiative effect

8 Laki Eruption in Iceland (8 June February 1784) Second largest flood lava eruption in historical time Iceland s biggest natural disaster 12/8/2017 8

9 Laki Eruption What makes it special Lava = 14.7 km 3 Tephra = 0.4 km 3 SO 2 = 100 million tons Very big eruption with big impact! 12/8/2017 9

10 Laki Eruption - venue for Big Science Worked on it since 1983 Subject of 6 PhD studies; one more on the way and 1 MSc study 34 refereed journal papers published on different aspects of the eruption!

11 Benjamin Franklin (1784) During several of the summer months of the year 1783, when the effect of the sun s rays to heat the earth in these northern regions should have been greatest, there existed a constant fog over all Europe, and great part of North America. This fog was of a permanent nature; it was dry, and the rays of the sun seemed to have little effect towards dissipating it, as they easily do a moist fog, arising from water. They were indeed rendered so faint in passing through it, that when collected in the focus of a burning glass, they would scarce kindle brown paper. Of course, their summer effect in heating the earth was exceedingly diminished. Hence the earth was early frozen, Hence the first snows remained on it unmelted, and received continual additions. Hence the air was more chilled, and the winds more severely cold. Hence perhaps the winter of , was more severe, than any that had happened for many years. The cause of this universal fog is not yet ascertained. Whether it was adventitious to this earth, and merely a smoke, proceeding from the consumption by fire of some of those great burning balls or globes which we happen to meet within our rapid course round the sun, and which are sometimes seen to kindle and be destroyed in passing our atmosphere, and whose smoke might be attracted and retained by our earth; or whether it was the vast quantity of smoke, long continuing to issue during the summer from Hecla in Iceland, and that other volcano which arose out of the sea near that island, which smoke might be spread by various winds, over the northern part of the world, is yet uncertain. Laki Eruption - venue for Big Science

12 PROMOTED The French naturalist M. Mourgue de Montredon was the first to tie the dry fog of 1783 to an eruption in Iceland; He did so in a lecture at the Royal Academy of Montpellier, on 7 August OTHERS J. L. Christ, German naturalist [1783] Prof. C. G. Kratzenstein, Univ. Copenhagen [1784, B. Franklin. US ambassador in Paris [1784] S. Palsson, Icelandic naturalist [1784]

13 Laki pumice Laki crater Laki NE cone -row Laki - Eruption History 12/8/

14 Eruption History I Laki eruption (8 June February 1784) 12/8/ explosive; tephra = 0.4 km 3 Effusive; lava = 14.7 km 3

15 Laki: Eruption Data Laki fissure The Laki eruption lasted for 8 months, with continuous effusive emissions into the troposphere, as well as 10 El Chichón-size eruptions to a height of km, into the lower stratosphere. 12/8/

16 Sub-Plinian Explosive Phases High magma discharge & intense fountaining scoria/ash fall Gas-charged subplinian eruption columns lava fountains Laki pumice particle-rich gas phase fountain-fed lava Lining of degassed magma Extremely efficient vent degassing > 70% of dissolved gas released 12/8/

17 Laki eruption columns: heights H = 8.2Q 1/4 central vent or short fissure 12/8/

18 Atmospheric Mass Loading of Sulfur and Other Volatiles 12/8/

19 Sulfur Measurements plume column 490 ppm S vents lava 205 ppm S rising magma 350 ppm S magma in reservoir 1675 ppm S 12/8/

20 Laki 15 km 200 Mt sulfuric aerosols 98 Mt SO 2 column plume 122 Mt SO 2 vents 24 Mt SO 2 lava rising magma 139 Mt SO 2 H 2 O = 235 Mt magma in reservoir Mt (megaton) = 1x10 9 kg = 1 Tg 12/8/

21 Sulfur Loadings by Laki-2 12/8/

22 Plume and Aerosol Dispersal 12/8/

23 Laki Haze: Records of Dispersal Covered the northern quarter of the globe Eyjafjallajökull 2010

24 Laki Haze: Records of Dispersal Covered the northern quarter of the globe

25 Plume and Aerosol Cloud Transport

26 Aerosol Removal -Tropospheric Dispersal 25 Mt remained climatic effects aloft for >1 year 175 Mt removed, >1000 kg H 2 SO 4 environmental effects per km 2 Plumes and aerosols transported within the polar jet stream and dispersed to the surface by subsiding air masses in high pressure cells 12/8/

27 Impact Radiative of Flood Effects Basalt of Eruptions Laki Loading >200 megatons of sulfate aerosols for 1 year 12/8/

28 Atmospheric effects: Environmental Impact Science, 19 Nov /8/

29 Laki and the Haze Famine Environmental Disaster! killed >75% of livestock and >20% of the population at the time Skull from excavation at Búland farm Sulfur and fluorine contaminated ash fall led to the haze famine

30 Environmental Impact Elsewhere The Dry Fog van Swinden 1783 Now some days before the 24 June (at Franeker thence from the 19 th ) a certain continuos haze was seen, but this excited no attention, since this phenomenon is not unusual here,.. But on the 24 th day of the month the haze, which was stronger than on the preceding day, brought with it a very distinct sulfurous odor..many experienced very troublesome headaches and respiratory difficulties, similar to that which they experienced while the atmosphere around us was filled with the vapor of burned sulfur... In the morning of the 25 th the fields showed a very sad appearance. The green color of the trees and plants had disappeared and the earth was covered with drooping leaves. One would easily have believed that it was October or November. Moreover the injury, and falling of leaves, lasted for some time. 12/8/

31 Laki plumes Distal Effects 25 Mt 175 Mt Dry Fog 175 Mt of H 2 SO 4 aerosols removed from the atmosphere in summer and fall of 1783 (Thordarson and Self, 2003) equivalent to deposition of 1000 kg sulfuric acid per km 2 widespread damage to vegetation and crop in Europe consistent with pollution from acid precipitation significant increase in mortality in England; up to 25% (Grattan et al., 2003) 12/8/

32 Atmospheric Effects: Climatic Impact 12/8/

33 Historical Records Summer 1783 unusual weather hot July in W-Europe very intense thunderstorms cold in North Atlantic, Alaska (?) snow fall in Poland cold and rainy in Japan Winter landmark winter in Europe and E-US long winter, intense frost inland seas and straits froze over ice on Mississippi at New Orleans moderate in Eurasia and Japan (?) intense spring floods in Europe 12/8/

34 Summer of 1783 Unusually Thor Thordarson Hot July in 1783 (Thordarson and Self 2003) Global Circulation Modelling (Oman et al 2006

35 Significant at 90% level Reconstruction from Luterbacher et al. (2004) Anomalies based on 31 yr mean,

36 12/8/2017 Reconstruction from Luterbacher et al. (2004) 36 Anomalies based on 31 yr mean, Significant at 90% level

37 12/8/2017 Reconstruction from Luterbacher et al. (2004) 37 Anomalies based on 31 yr mean, Significant at 90% level

38 Temperature Records Europe and Eastern US Temperature record Europe Frequency of zonal weather type in the period T = -1.3 o C 12/8/

39 50 mb after heating Aerosol cloud Jet stream axis Tropopause North Pole Tropics Aerosol heating decreases Equator-Pole temperature gradient, decreasing height gradient, and makes jet stream (polar vortex) weaker. This idea is under investigation with climate modeling. 12/8/

40 Laki Cloud Cover and Precipitation Anomaly Summer 1783 Strong decreases in cloud cover over northern India and northern Sahel region of Africa (from -4 to -10%) Some increases in cloud cover over Europe and Northern Asia Less precipitation over northern India and northern Sahel region of Africa (from -1 to -3 mm/day) Significant precipitation decreases over both the Nile and Niger River watersheds lead to decreased runoff from those rivers. Laki weaken the African and Indian monsoon circulations.

41 Volcano Fatalities The most typhus deadly Tambora epidemic eruptions in of Ireland killed the 35% 20th spread of century the to England people were and on the Scotland, Sumbawa 1902 Pelée killing (48,000 eruption 65,000. in 2 on years, Bad Martinique, 10,000 harvests immediately which in India killed The 1783 Laki eruption killed 75% of all the livestock produced and 29,000 38,000 and a cholera the from 1985 hunger epidemic, Nevado and which disease) del spread Ruiz and eruption, to 44,000 Asia and on Europe Lombok which and (the killed 21% 160 great of >23,000 km all to cholera the the from people east. pandemic mud on flows Iceland. of (lahars) the century). from the melted ice cap on the top of the volcano. Thor Thordarson Simkin et al. (2001)

42 Fatalities from Laki deaths in Iceland 25% increase in death rates in France and UK 0.5 million dead in India due to Laki induced changes in the monsoon pattern 1 million dead in Japan due to crop failure and subsequent famine Thor Thordarson Schmidt et al. (2011&2012)

43 Tephra fall and infrastructure 10 to 30 cm required to collapse buildings depends on construction type roof span pitch angle ~7.8kN/m 2 ~1.3kN/m 2

44 air space air closed airports closed airspace mechanical damage

45 electricity falls of volcanic ash can disrupt supply ash properties soluble components dry/wet fine/course size distribution systems low voltage more vulnerable than high

46 water supplies Tephra fall and sulfuric haze can cause contamination of water supplies three main types turbidity acidity chemical tephra fall clean-up results in high water usage

47 Impact on ground transport?

48 Effects of lava flows destruction & construction Heimaey, Iceland 1973

49 Thank You