Volcanos: The Choking Grip Of Mother Nature

By Jean Bush

The eruption of the Eyjafjallajokul has caused flooding, evacuations and the disruption of flights in both America and Europe.

Friday, April 16, 2010 – Volcanic ash from Iceland snarled air traffic across Europe for a second day Friday, causing the cancellation of some 17,000 flights, according to the intergovernmental body that manages European air travel, according to the Protravel Int. website.

Explosive eruptive phase of the Eyjafjallajökull volcano, Iceland, begins 14 April 2010

The eruption plume from Iceland that has caused the unprecedented catastrophic disruption of air traffic and closure of airspaces over northern Europe is due to an explosive eruptive phase that began at the Eyjafjallajökull volcano on April 14. It is a continuation of eruptive activity in the Eyjafjallajökull volcanic system that began 20 March 2010. During an initial eruptive phase from 20 March to 12 April lava flowed from eruptive vents on the volcano flanks, outside its ice cover. The lava erupted in the initial phase is alkali-olivine basalt, with silica content of about 47%.

After a short hiatus in eruptive activity a new set of craters opened up in early morning of 14 April under the volcano’s ice covered central summit caldera. This eruptive phase was preceded with a swarm of earthquakes from around 23:00 on 13 April to 1:00 on 14 April. The earthquake swarm was followed by the onset of seismic eruption tremor. Meltwater started to emanate from the ice cap around 7 o’clock on April 14 and eruption plume was observed in the early morning. Visual observations were limited by cloud cover over the volcano, but an airplane of the Iceland coast Guard imaged with eruptive crates with radar instrument. Series of vents along a 2 km long north-south oriented fissure were active, with meltwater flowing down northern slopes of the volcano, but also to the south. Ash loaded eruption plume rose to more than 8 km height, deflected to the east by westerly winds.

Jokulhlaups (floods of meltwater) reached the lowlands around the volcano with peak flow around noon on April 14, with destruction of roads, infrastructure, and farmlands. No fatalities as people had been evacuated from hazardous areas. Tephra fall begins in southeast Iceland. A second jokulhlaup/lahar emanates from the ice cap down the Markarfljot valley in the evening.

On 15 April the eruption plume reaches mainland Europe with closure of airspace over large part of Northern Europe. Activity continues at a similar level with ash generation and flow of meltwater in pulses.  Jokulhlaup/lahar occurs in the evening. On April 16 some variability occurs in seismic tremor and tephra generation, but overall the eruptive activity remains stable. Pulsating eruptive plume reaches above 8 km, with overall height of 5 km. large closures of airspace continue.

Chemical analyses of ash samples reveal fluorine rich intermediate eruptive products with silica content of 58%, more evolved than in the initial lava producing phase of the eruptive activity. The magma composition may reflect evolution from alkali-olivine basalt by crystal fractionation as erupted in the initial phase. ( Institute of Earth Sciences – Iceland.)

According to the Smithsonian Institution’s Global Volcanism Program’s Rick Wunderman, the range of volcanic activity can range from 20 minutes to 700 years. (LA Times.)

The most famous volcano in modern history is Krakatoa, a violent, explosive mountain that may have changed the face of history.

Krakatoa (Indonesian: Krakatau), also spelled Cracatoa or Krakatau, is a volcanic island made of a’a lava^[2] in the Sunda Strait between the islands of Java and Sumatra in Indonesia. The name is used for the island group, the main island (also called Rakata), and the volcano as a whole.

The best-known eruption of Krakatua culminated in a series of massive explosions on August 26–27, 1883, which was among the most violent volcanic events in modern and recorded history.

With a Volcanic Explosivity Index (VEI) of 6,^[3] the eruption was equivalent to 200 megatons of TNT (840 PJ)—about 13,000 times the nuclear yield of the Little Boy bomb (13 to 16 kT) that devastated Hiroshima, Japan during World War II and four times the yield of the Tsar Bomba (50 MT), the largest nuclear device ever detonated.

The 1883 eruption ejected approximately 21 cubic kilometres (5.0 cu mi) of rock, ash, and pumice.^[4]

The cataclysmic explosion was distinctly heard as far away as Perth in Western Australia, about 1,930 miles (3,110 km) away, and the island of Rodrigues near Mauritius, about 3,000 miles (5,000 km) away.^[5]

Near Krakatau, according to official records, 165 villages and towns were destroyed and 132 seriously damaged, at least 36,417 (official toll) people died, and many thousands were injured by the eruption, mostly from the tsunamis that followed the explosion. The eruption destroyed two-thirds of the island of Krakatoa.

Eruptions at the volcano since 1927 have built a new island in the same location, named Anak Krakatau (Indonesian: “Child of Krakatoa“). This island currently has a radius of roughly 2 kilometres (1.2 mi) and a high point around 300 metres (980 ft) above sea level, growing 5 metres (16 ft) each year.  (Wikipedia)

535 AD event

David Keys, Ken Wohletz, and others have postulated that a violent volcanic eruption, possibly of Krakatoa, in 535 may have been responsible for the global climate changes of 535-536.^[8] Keys explores what he believes to be the radical and far-ranging global effects of just such a putative 6th-century eruption in his book Catastrophe: An Investigation into the Origins of the Modern World. Additionally, in recent times, it has been argued that it was this eruption which created the islands of Verlaten, Lang, and the beginnings of Rakata—all indicators of early Krakatoa’s caldera‘s size. To date, however, little datable charcoal from that eruption has been found.

Thornton (p. 47) mentions that Krakatoa was known as “The Fire Mountain” during Java’s Sailendra dynasty, with records of seven eruptive events between the 9th and 16th centuries. These have been tentatively dated as 850, 950, 1050, 1150, 1320, and 1530 (all AD).

The extreme weather events of 535–536 were the most severe and protracted short-term episodes of cooling in the Northern Hemisphere in the last 2,000 years.^[1] The event is thought to have been caused by an extensive atmospheric dust veil, possibly resulting from a large volcanic eruption in the tropics,^[2] or debris from space impacting the earth.^[3] Its effects were widespread, causing unseasonal weather, crop failures and famines worldwide.^{[3] (Wikipedia)}

Tree ring analysis by dendrochronologist Mike Baillie, of the Queen’s University of Belfast, shows abnormally little growth in Irish oak in 536 and another sharp drop in 542, after a partial recovery.[The Holocene 1994 fig 3 page 215 "Dendrochronology, the AD536 dust-veil event"] Similar patterns are recorded in tree rings from Sweden and Finland, in California’s Sierra Nevada and in rings from Chilean Fitzroya trees.^{[citation needed]} Ice cores from Greenland and Antarctica show evidence of substantial sulfate deposits around 533–534 ± 2 years, evidence of an extensive acidic dust veil.^{[2] (Wikipedia)}

The 536 event and ensuing famine has been suggested as an explanation for the sacrifice by Scandinavian elites of large amounts of gold at the end of the Migration Period, possibly to appease the angry gods and get the sunlight back.^[17][18]

The decline of Teotihuacán, a huge city in Mesoamerica, is also correlated with the droughts related to the climate changes, with signs of civil unrest and famines.^{[citation needed]}

David Keys’ book speculates that the climate changes may have contributed to various developments, such as the emergence of the Plague of Justinian, the decline of the Avars, the migration of Mongolian tribes towards the West, the end of the Persian Empire, the rise of Islam and the fall of Teotihuacán.^{[citation needed]} In 2000, a 3BM Television production (for WNET and Channel Four) capitalized upon Keys’ book. This documentary, under the name Catastrophe! How the World Changed, was broadcast in the U.S. as part of PBS‘s Secrets of the Dead series. However, Keys and Wohletz’ ideas are not widely accepted at this point.^{[citation needed]} Reviewing Keys’ book, the British archaeologist Ken Dark commented that “much of the apparent evidence presented in the book is highly debatable, based on poor sources or simply incorrect” and that “Nonetheless, both the global scope and the emphasis on the 6th century AD as a time of wide-ranging change are commendable, and the book contains some fascinating and obscure information which will be new to many. However, it fails to demonstrate its central thesis and does not offer a convincing explanation for the many changes discussed.”^{[19]  (Wikipedia)}

However, Keys and Wohletz’ ideas are not widely accepted at this point.^{[citation needed]} Reviewing Keys’ book, the British archaeologist Ken Dark commented that “much of the apparent evidence presented in the book is highly debatable, based on poor sources or simply incorrect” and that “Nonetheless, both the global scope and the emphasis on the 6th century AD as a time of wide-ranging change are commendable, and the book contains some fascinating and obscure information which will be new to many. However, it fails to demonstrate its central thesis and does not offer a convincing explanation for the many changes discussed.”^{[19]  (Wikipedia).}

^{Volcanic ash is not dust-like in composition, rather it is very fine-grained rock and glass and can be as large as 1/12th of an inch to 1/25,000 of an inch and can, if inhaled, damage animal and human lung tissue and can shut down airline engines by restricting airflow.   These ash clouds can, if widely dispersed enough, can block sunlight and cause a temporary cooling of the planet’s surface by as much as one degree.}

^{However, all of this will someday be relegated to the dustbin of history.  As we advance further and further with our technology, we will, again, presume to have all the control we need to manage our comfortable lives.  It will take another good slap from Mother Nature to show us how wrong we will always be.}