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43-663: Holuhraun ( [ˈhɔːlʏˌr̥œyːn] ) is a lava field just north of the Vatnajökull ice cap , in the Icelandic Highlands , in Suður-Þingeyjarsýsla , Northeastern Region , Iceland . The lava field was created by fissure eruptions. After a research expedition in 1880, the lava field was initially called Kvislarhraun [ˈkʰvɪstlar̥ˌr̥œyːn] . Four years later, it received its current name from geologist and geographer Þorvaldur Thoroddsen . Holuhraun

86-522: A 25 km-long (15.5 mi) fissure of at least 130 vents opened with phreatomagmatic explosions because of the groundwater interacting with the rising basalt magma . Over a few days the eruptions became less explosive, Strombolian , and later Hawaiian in character, with high rates of lava effusion . This event is rated as 4 on the Volcanic Explosivity Index , but the eight-month emission of sulfuric aerosols resulted in one of

129-432: A constant fog over all Europe, and a 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

172-451: A southwest to northeast direction. The system erupted violently over an eight-month period between June 1783 and February 1784 from the Laki fissure and the adjoining volcano Grímsvötn. It poured out an estimated 42 billion tonnes or 14 km (18 × 10 ^  cu yd) of basalt lava as well as clouds of poisonous hydrofluoric acid and sulfur dioxide compounds that contaminated

215-686: A thick haze to spread across western Europe, resulting in many thousands of deaths throughout the remainder of 1783 and the winter of 1784. The summer of 1783 was the hottest on record and a rare high-pressure zone over Iceland caused the winds to blow to the south-east. The poisonous cloud drifted to Bergen in Denmark–Norway , then spread to Prague in the Kingdom of Bohemia (now the Czech Republic) by 17 June, Berlin by 18 June, Paris by 20 June, Le Havre by 22 June, and Great Britain by 23 June. The fog

258-430: A wrinkled or folded sheet, while pillow lava is bulbous, and often looks like a pile of pillows atop one another. An important aspect of lava flow morphology is a phenomenon known as lava flow inflation. This occurs in pāhoehoe flows that have a high effusion rate, and initially forms a thin crust atop the lava flow. The fluid lava underneath the crust continues to increase due to the sustained high effusion rate, and thus

301-442: Is consistently increasing in quality, but the many micro factors directing lava flow and shape, such as source geometry and lava extrusion rate, limit the accuracy that is currently available. Laki Laki ( Icelandic pronunciation: [ˈlaːcɪ] ) or Lakagígar ( [ˈlaːkaˌciːɣar̥] , Craters of Laki ) is a volcanic fissure in the western part of Vatnajökull National Park , Iceland , not far from

344-507: Is no longer accepted. In the early hours of 29 August 2014, a small fissure eruption occurred in Holuhraun at the northern end of a magma intrusion which had moved progressively north, since 16 August, from the Bárðarbunga volcano. The progression of the magma intrusion was accompanied by an earthquake swarm . The eruption began just after midnight and stopped at 04:00 GMT. The active fissure

387-590: The Askja caldera , and the Bárðarbunga volcano is 41.39 km (25.7 mi) to the south-west of Holuhraun. Holuhraun is traversed by an unnumbered road, which connects to the Route F910 gravel road at both the east and the west ends. Located at the northern and southern extensions of the Bárðarbunga and Askja fissure systems, respectively, the soil is mainly composed of lavas derived from these volcanoes, either in

430-597: The Sahel of Africa, resulting in, among other effects, low flow in the River Nile . The resulting famine that afflicted Egypt in 1784 cost it roughly one-sixth of its population. The eruption was also found to have affected South Arabia and the already ongoing Chalisa famine in India. The Great Tenmei famine of 1782–1788 in Japan may have been worsened by the Laki eruption. In

473-695: The Treaty of Paris , which formally ended the American Revolutionary War . A huge snowstorm hit the South ; the Mississippi River froze at New Orleans and there were reports of ice floes in the Gulf of Mexico . Gilbert White recorded his perceptions of the event at Selborne , Hampshire , England: The summer of the year 1783 was an amazing and portentous one, and full of horrible phaenomena; for besides

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516-504: The Earth was exceedingly diminished. Hence the surface 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 1783–84 was more severe than any that had happened for many years. The cause of this universal fog is not yet ascertained ... or whether it was the vast quantity of smoke, long continuing, to issue during

559-462: The alarming meteors and tremendous thunder-storms that affrighted and distressed the different counties of this kingdom, the peculiar haze, or smokey fog, that prevailed for many weeks in this island, and in every part of Europe, and even beyond its limits, was a most extraordinary appearance, unlike anything known within the memory of man. By my journal I find that I had noticed this strange occurrence from June 23 to July 20 inclusive, during which period

602-399: The contaminated grass, while humans deaths were mostly from the subsequent famine. The parish minister and provost of Vestur-Skaftafellssýsla , Jón Steingrímsson (1728–1791), grew famous for the eldmessa [ˈɛltˌmɛsːa] ("fire mass ") that he delivered on 20 July 1783. The church farm of Kirkjubæjarklaustur was endangered by a branch of the lava flow that halted not far from

645-434: The convective eruption column to altitudes of about 15 km (50,000 ft). The eruption continued until 7 February 1784, but most of the lava was ejected in the first five months. One study states that the event "occurred as ten pulses of activity, each starting with a short-lived explosive phase followed by a long-lived period of fire-fountaining". Grímsvötn volcano, from which the Laki fissure extends, also erupted at

688-469: The eastern side of Holuhraun, in the Kverkfjöll area. Hrímalda [ˈr̥iːmˌalta] , Urðarháls [ˈʏrðarˌhauls] and Kistufell [ˈcʰɪstʏˌfɛtl̥] are to the west of Holuhraun, with Dyngjuháls [ˈtiɲcʏˌhauls] and Trölladyngja beyond. The Dyngjujökull glacier, which is part of Vatnajökull, is to the immediate south. Holuhraun is about 15 km (9.3 mi) south of

731-458: The entire "structure" increases in size, up to four meters in height. This anomaly can expose important physics and mechanisms behind lava flow that was not previously known. The structure of lava fields also vary based on geographic location. For example, in subaqueous lava fields, sheet flow lava is found near volcanoes characterized by fast-flowing centers, like the Galapagos Rift , while on

774-534: The farm while the Rev. Jón and his parishioners were worshipping in the church. The spot at which the lava diverted away from the church became known thereafter as Eldmessutangi [ˈɛltˌmɛsːʏˌtʰauɲcɪ] ("Fire Mass Point"). This past week, and the two prior to it, more poison fell from the sky than words can describe: ash, volcanic hairs , rain full of sulfur and saltpeter , all of it mixed with sand. The snouts, nostrils, and feet of livestock grazing or walking on

817-429: The form of flows or alluvial deposits of volcanic origin. The geological configuration, along with the presence of nearby subglacial volcanoes such as Bárðarbunga and Grímsvötn , is responsible for the risk of jökulhlaups , which have affected Holuhraun repeatedly. Until 2014, the surface of the lava field was of an older lava flow, which was assumed to have erupted from a vent associated with Askja in 1797, but this

860-445: The grass turned bright yellow and raw. All water went tepid and light blue in color and gravel slides turned grey. All the earth's plants burned, withered and turned grey, one after another, as the fire increased and neared the settlements. There is evidence that the Laki eruption weakened African and Indian monsoon circulations, leading to between 1 and 3 millimetres (0.04 and 0.12 in) less daily precipitation than normal over

903-671: The haze dissipated in the autumn. The winter of 1783–1784 was very severe; the naturalist Gilbert White in Selborne , Hampshire , reported 28 days of continuous frost. The extreme winter is estimated to have caused 8,000 additional deaths in the UK. During the spring thaw, Germany and Central Europe reported severe flood damage. This is considered part of a volcanic winter . The meteorological impact of Laki continued, contributing significantly to several years of extreme weather in Europe. In France,

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946-545: The lanes and hedges that they rendered the horses half frantic, and riding irksome. The country people began to look, with a superstitious awe, at the red, louring aspect of the sun; ... Benjamin Franklin recorded his observations in America in a 1784 lecture: 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 greater, there existed

989-412: The lava flow when it was fluid. The ridges and patterns on top of the lava field show the direction of the lava channels and the often active lava tubes that may be underneath the solidified "crust." It can also reveal whether the lava flow can be classified as pāhoehoe or 'a'ā . The two main types of lava field structures are defined as sheet flow lava and pillow lava . Sheet flow lava appears like

1032-663: The main eruption site, on 5 September. The new fissures were substantially smaller than the older fissure. By 7 September, the lava flow had extended 11 km (6.8 mi) to the north, and had reached the main western branch of the Jökulsá á Fjöllum river. The eruption showed no visible activity in the southern fissure, on the evening of 7 September. The lava flow is considered to be the largest in recent decades in Iceland and covered 44 km (17 sq mi) on 29 September. The volcanic eruption in Holuhraun continued with similar intensity as

1075-603: The most important climatic and socially significant natural events of the last millennium. The eruption, also known as the Skaftáreldar [ˈskaftˌauːrˌɛltar̥] (" Skaftá fires") or Síðueldur [ˈsiːðʏˌɛltʏr̥] produced an estimated 14 km (18 × 10 ^  cu yd) of basalt lava, and the total volume of tephra emitted was 0.91 km (1.2 × 10 ^  cu yd). Lava fountains were estimated to have reached heights of 800 to 1,400 m (2,600 to 4,600 ft). The gases were carried by

1118-527: The other hand pillow lava fields are found near more slow-flowing centers, like the Mid-Atlantic Ridge . The extent of large lava fields is most readily studied from the air or in satellite photos, where their commonly dark, near-black color contrasts sharply with the rest of the landscape. Current computer models are mostly unable to predict the placement of lava fields due to the inability to anticipate random environmental influences. Computer modeling

1161-421: The population died in the famine after the fissure eruptions ensued. (Some sources specify a death toll of between 9,000 to 9,500 people.) Approximately 80% of sheep (190,500 head), 50% of cattle (11,500 head) and 50% of horses (28,000 head) died because of dental fluorosis and skeletal fluorosis from the 8 million tons of fluorine that were released. The livestock deaths were primarily caused by eating

1204-476: The previous few weeks. The lava field covered 63 km (24 sq mi) in late October. On 11 November, it was reported that the lava field extended to 70 km (27 sq mi) and more than 1 km (0.24 cu mi) in volume - the largest in Iceland since the Laki eruption of 1783. The eruption ended on 27 February 2015. The Holuhraun lava field measures more than 85 km (33 sq mi) and

1247-519: The same year, Mount Asama erupted in Japan ( Tenmei eruption ). The eruption may have affected a drought in eastern China. An estimated 120,000,000 tonnes of sulfur dioxide was emitted, about three times the total annual European industrial output in 2006 (but delivered to higher altitudes, hence its persistence), and equivalent to six times the total 1991 Mount Pinatubo eruption . This outpouring of sulfur dioxide during unusual weather conditions caused

1290-563: The sequence of extreme weather events included a failed harvest in 1785 that caused poverty for rural workers, as well as droughts, bad winters and summers. These events contributed significantly to an increase in poverty and famine that may have contributed to the French Revolution in 1789. Laki was only one factor in a decade of climatic disruption, as Grímsvötn was erupting from 1783 to 1785, and there may have been an unusually strong El Niño effect from 1789 to 1793. In North America,

1333-703: The soil, leading to the death of over 50% of Iceland's livestock population, and the destruction of the vast majority of all crops. This led to a famine which then killed at least a fifth of the island's human population, although some have claimed a quarter. The Laki eruption and its aftermath caused a drop in global temperatures, as 120 million tonnes of sulfur dioxide was spewed into the Northern Hemisphere . This caused crop failures in Europe and may have caused droughts in North Africa and India . On 8 June 1783,

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1376-546: The summer from Hekla 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. According to contemporary records, Hekla did not erupt in 1783; its previous eruption was in 1766. The Laki fissure eruption was 70 km (45 mi) east and the Grímsvötn volcano was erupting about 120 km (75 mi) northeast. Katla , only 50 km (31 mi) southeast,

1419-463: The time, from 1783 until 1785. The outpouring of gases, including an estimated 8 million tonnes of fluorine and an estimated 120 million tonnes of sulfur dioxide , gave rise to what has since become known as the "Laki haze" across Europe. The consequences for Iceland, known as the Móðuharðindin [ˈmouːðʏˌharðɪntɪn] ( mist hardships), were disastrous. An estimated 20–25% of

1462-404: The volcanic fissure of Eldgjá and the small village of Kirkjubæjarklaustur . The fissure is properly referred to as Lakagígar, while Laki is a mountain that the fissure bisects. Lakagígar is part of a volcanic system centered on the volcano Grímsvötn and including the volcano Þórðarhyrna . It lies between the glaciers of Mýrdalsjökull and Vatnajökull , in an area of fissures that run in

1505-452: The volume is around 1.6 km (0.38 cu mi). Several names were proposed for the new lava field in the Holuhraun area, among them Flæðahraun , Nornahraun , and Urðarbruni . Finally, the decision was to keep the existing name Holuhraun , which is also consistent with current geological thought. Lava field The final morphology of a lava field can reveal properties such as internal structure, composition, and mechanics of

1548-414: The wind varied to every quarter without making any alteration in the air. The sun, at noon, looked as blank as a clouded moon, and shed a rust-coloured ferruginous light on the ground, and floors of rooms; but was particularly lurid and blood-coloured at rising and setting. All the time the heat was so intense that butchers' meat could hardly be eaten on the day after it was killed; and the flies swarmed so in

1591-631: The winter of 1784 was the longest and one of the coldest on record. It was the longest period of below-zero temperatures in New England , with the largest accumulation of snow in New Jersey , and the longest freezing over of Chesapeake Bay . At the time, the capital of the United States was situated on the Chesapeake at Annapolis, Maryland ; the weather delayed Congressmen who were traveling there to vote for

1634-434: Was about 600 m (660 yd) in length. Another fissure eruption started in Holuhraun at around 05:05 GMT on the morning of 31 August 2014, in the same rift as the eruption which had occurred two days earlier. The eruptive fissure was estimated to be 1.5 km (0.93 mi) long. By 4 September, the total area of the lava flow was estimated at 10.8 km (4.2 sq mi). Two new eruptive fissures formed south of

1677-439: Was informed by a tenant that finding himself cold in bed, about three o'clock in the morning, he looked out at his window, and to his great surprise saw the ground covered with a white frost: and I was assured that two men at Barton, about three miles (five kilometres) off, saw in some shallow tubs, ice of the thickness of a crown-piece . Sir John goes on to describe the effect of this "frost" on trees and crops: The aristae of

1720-473: Was most affected. The records show that the additional deaths were among outdoor workers; the death rate in Bedfordshire , Lincolnshire , and the east coast was perhaps two or three times the normal rate. It has been estimated that 23,000 British people died from the poisoning. The weather became very hot, causing severe thunderstorms with large hailstones that were reported to have killed cattle , until

1763-468: Was so thick that ships stayed in port, unable to navigate, and the sun was described as "blood coloured". Inhaling sulfur dioxide gas causes victims to choke as their internal soft tissues swell – the gas reacts with the moisture in the lungs and produces sulfurous acid . The local death rate in Chartres was up by 5% during August and September, with more than 40 dead. In Great Britain, the east of England

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1806-523: Was still renowned after its spectacular eruption 28 years earlier in 1755. Sir John Cullum of Bury St Edmunds , Suffolk , England, recorded his observations on 23 June 1783 (the same date on which Gilbert White noted the onset of the unusual atmospheric phenomena), in a letter to Sir Joseph Banks , then President of the Royal Society : ... about six o'clock, that morning, I observed the air very much condensed in my chamber-window; and, upon getting up,

1849-472: Was the site of a volcanic eruption which began on 29 August 2014 and produced a lava field of more than 85 km (33 sq mi) and 1.4 km (0.34 cu mi) – the largest in Iceland since 1783. Holuhraun is situated at the southern end of Ódáðahraun [ˈouːˌtauːðaˌr̥œyːn] , which is one of the largest lava fields in the country. The main volume of the Jökulsá á Fjöllum river flows from

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