Elaine Meinel Supkis
Here we are, on the verge of a possible major volcanic event. One that can have a huge impact if it is big enough and the chances of that are fairly high for Merapi is not only a large volcano, it is one of a chain of very dirty volcanoes prone to exploding violently. I remember when Mt. Agung blew up right after my sister Mary's birthday in 1963.
The mountain is also revered by many locals, who believe mystical sprits live in the volcano's crater. Many say they are waiting for specific signs - such as clouds in the shape of a sheep's fleece - to show them an eruption is imminent.'MOUNTAIN OF FIRE'
Merapi has had 68 historic eruptions since 1548
In 1994 a gas cloud burned 60 people to death
About 1,300 died when it erupted in 1930
Most violent eruption in recent history was in 1872
Major eruption in 1006 covered all of central Java with ashMerapi, which means "mountain of fire", is one of the most fearsome volcanoes in the Pacific "Ring of Fire".
A gas cloud from the volcano's last eruption in 1994 killed 60 people.
One of its deadliest eruptions was in 1930, when about 1,300 people were killed.
Great volcanoes have great effects. Where they happen to blow, how high the cloud of ash goes, volume of ash, chemical compostion of the tuff, whether it is near civilizations (bad luck!) or far away, makes a big difference. Many times, volcanic eruptions in the Alaskan chain has no terrific effect because it is at the top of the planet but major eruptions at the equator can spread across the entire stratosphere and greatly alter the climate. Some were not so great an effect but due to the chemistry of the ash, caused terrific events to unfold due to famine and death.
My parents are very well known for pioneering work in high atmospheric fine ash, volcanic gas studies. I remember vividly how it all started.
We were driving along in the desert heading due west into the setting sun, coming back from the McDonald observatory outside of El Paso, Texas. As Aden drove, Marjorie began to remark that the sunset looked marveously odd. It became increasingly pyschodelic. At the observatory, my parents were puzzled by the dimness of the light the telescope recieved and wondered if there was some sort of dust storm.
Back then, there was little immediate communication from distant parts of Indonesia, there were no satellite weather monitors nor direct longdistance calling to that part of Asia. We had a shortwave radio but there was no news story about a major eruption.
But there was one! And unlike all the previous ones since Krakatoa which didn't expell enough gas and dust to the higher levels of the stratosphere, this one shot right up quite powerfully. As the sky darkened, paradoxically, it lit up. Dad stopped the car and hauled out his camera and other equipment and began observations. My parents noted how the east was also lit up, the zenith shone "like during an aurora."
They become most excited. We wondered if this was a one day deal. It wasn't. Over the months, the sky grew ever more amazingly brilliant. It was the most beautiful late summer and into fall. I associate the assassination of Kennedy with the blood red sunsets.
The weather changed. It rained and rained in the desert, the desert wept while muffled overhead with grey clouds and it even snowed.Aden and Marjorie Meinel described a very simple method for estimating the altitude of the aerosol layers that cause extended twilights. The method is described in "Sunsets, Twilights, and Evening Skies" (Cambridge University Press, 1983), a fine book which belongs on every sky watcher's bookshelf.The Meinel method is based on the duration of the twilight glow. If you watch a sunset on a clear evening, you will notice that the entire western sky is brightly illuminated for at least 10 minutes. Gradually, the twilight forms a bright arc in the sky. The time between the setting of the Sun and the upper edge of the twilight glow is closely related to the altitude of aerosol layers in the stratosphere.
The nearby chart for estimating the height of stratospheric aerosols from the duration of the twilight glow was made using the equations given by the Meinels in "Sunsets, Twilights, and Evening Skies." The spreadsheet from which the chart was made is available at www.forrestmims.org (click on the Scientific Research page).
My grandfather proposed Krakatoa affected the sunsets and weather patterns and he was pooh-poohed. Well, my mother was so happy to prove him right. Now it seems, everyone knows this and would find it hard to believe that once upon a time, it was not accepted by scientists!
Just like all my yap here about how it is very possible that the universe is not flying apart at all. Laugh today, agree tomorrow.
The history of earth rests in the lap of the Great Volcanoes and Traps. We evolved into homosapiens with big brains thanks to the interface of volanoes and the variable sun. So it is of highest, indeed, survival depends on us figuring out how to co-exist with these two vital and utterly dangerous neighbors.Lakagigar (also called Skaftar) was the vent for the 1783-1784 eruption of Grimsvotn caldera. It was the second largest basaltic fissure eruption in historic time (after the ~935 eruption of nearby Eldgja) and caused notable atmospheric cooling and effects. Additional vents of Grimsvotn were active from May 1783 to May 1785.The eruption began on June 8, 1783 and lasted eight months. An estimated 14.731 cubic km of basalt was erupted and covered an area of 565 square km.
*snip*
Laki is also known for its atmospheric effects. The convective eruption column of Laki carried gases to altitudes of 15 km. These gases formed aerosols that caused cooling in the Northern Hemisphere, possibly by as much as 1 degree C. This cooling is the largest such volcanic-induced event in historic time. In Iceland, the haze lead to the loss of most of the islands livestock (by eating fluorine contaminated grass), crop failure (by acid rain) and the death of 9,000 people, one-quarter of the human residents (by famine).
This was not a great eruption but was extremely poisonous. The ash, even that which traveled thousands of miles, killed many things, wheat, sheep, trees, gardens. Most of the population of Iceland died and thousands and thousands had to flee Scotland. Not that the British overlords minded. They preferred to empty out the Highlands. Many came to America.Proto-revolutionary activity started when the French king Louis XVI (reigned 1774-1792) faced a crisis in the royal finances. The French crown, which fiscally equated the French state, owed considerable debt. During the régimes of Louis XV (ruled 1715-1774) and Louis XVI, several different ministers, including Turgot (Controller-General of Finances 1774-1776), and Jacques Necker (Director-General of Finances 1777-1781), unsuccessfully proposed to revise the French tax system to a more uniform system. Such measures encountered consistent resistance from the parlements (law courts), dominated by the "Robe Nobility", which saw themselves as the nation's guardians against despotism, as well as from court factions, and both ministers were ultimately dismissed. Charles Alexandre de Calonne, who became Controller-General of the Finances in 1783, pursued a strategy of conspicuous spending as a means of convincing potential creditors of the confidence and stability of France's finances.However, Calonne, having conducted a lengthy review of France's financial situation, determined that it was not sustainable, and proposed a uniform land tax as a means of setting France's finances in order in the long term. In the short-term, he hoped that a show of support from a hand-picked Assembly of Notables would restore confidence in French finances, and allow further borrowing until the land tax began to make up the difference and allow the beginning of repayment of the debt.
In France, the crops failed and many became very ill from the poisons. This is when the story of Marie Antoinette supposedly said, "Let them eat cake" arose. The fury over the deteriorating situation in the peasantry spilled out of the countryside and into the city where they fled. This turned a difficult political situation into a revolution.Mount Awu is one of Indonesia's most active volcanoes, and has erupted repeatedly since the 17th century.Nearly 3,000 people died when it blew up in 1812. The last major eruption was in 1966, when 40 people died and thousans were evacuated.
Napoleon invaded Russia the same year the Indonesian volcanic chain decided to begin a series of blowouts. Winter came roaring into Moscow very suddenly that year and Napoleon decided to run for his life as temperatures dropped like a rock in to sub zero ranges at the end of October. Much of his Grande Armee perished with some assistance from Cossack raiders harrying them as they ran.
Tambora's eruption was the greatest in recorded history. It caused huge hardship a year later here in the Northeast. It is a good thing Lewis and Clark went on their great expedition in 1804. If they did it a mere decade later, they might not have survived.
Every thousand years or so, a volcano erupts somewhere on the planet with enough power to significantly alter the global climate for years afterwards. Prodigious quantities of dust and sulphur aerosols are ejected into the atmosphere, preventing the Sun's rays from reaching the ground. Universal crop failures occur, temperatures drop dramatically, and living creatures across the globe die off in large numbers. Such an event occurred in 1815, on the island of Sumbawa in Indonesia - the explosion of the great Tambora volcano.*snip*
Five days later, on 10 April, a number of colossal explosions occurred, creating columns of volcanic material that stretched up to 40km into the sky. What goes up normally comes down, so when these columns collapsed, they formed pyroclastic flows - earth-hugging clouds of hot ash, rocks and pumice, that rampaged across the island killing everyone and everything in their path2. Almost the entire population of the Tambora province, over 10,000 people, were killed instantly by these flows. In addition, when these flows reached the sea, tsunamis up to 5m high were formed, that careered into neighbouring islands across the locality, killing yet more people in the immediate vicinity of the volcano.
*snip*
The longer term effects of Tambora were felt across the globe. In addition to the large quantities of ash, rocks and dust ejected by the volcano, over 200 million tonnes of sulphur dioxide gas were propelled into the stratosphere. This had the effect of limiting the amount of sunlight that reached the ground, so that temperatures, particularly across the Northern Hemisphere, began to fall dramatically4. Monsoon season was interrupted in India, possibly leading to a deadly outbreak of cholera that insinuated its way across the globe. Europe experienced widespread crop failures just as it was recovering from the effects of the Napoleonic Wars. Ireland had its first great famine. Devastating floods hit China. In North America, 1816 is remembered as 'the year without a summer', when snow fell during June and frost was still widespread during the month of July.
Artists, poets and writers were all inspired by the changes wrought by Tambora. One famous example is Turner's brilliant sunset paintings.
http://commons.
Of course, the most important aspect of all this is the possibility of extinction caused by volcanic events. First Science:
Every now and again in geology, as in any other science, evidence is obtained and presented that cannot easily be explained in terms of familiar processes or accepted ideas. Such a case was continental drift, proposed by Wegener in 1912, which languished as a theory for about 45 years because there was no logical explanation of HOW continents could move. The mechanism of seafloor spreading proposed in the late 1950's led to the development of the modern theory of plate tectonics, which provides an explanation for continental drift.The time relationship between flood basalt province formation and mass extinctions of organisms is another example of a scientific "hard nut to crack."
Extinction events are increasingly seen as important factors in the history of life on Earth, and recent studies suggest catastrophic causes for at least some mass extinctions. Two catastrophic processes that have been invoked are (1) impacts of asteroids or comets and (2) large volcanic eruptions. The end-Cretaceous (Cretaceous/Tertiary or K/T boundary) mass extinction has been convincingly correlated with the impact of a 10-km diameter asteroid with the Earth about 65 million years ago. Evidence of similar impacts has been found at the times of several other extinction events.
When you compare the age of LIPs with the estimated ages of stratigraphic boundaries involving significant biotic changes (dated according to the most recent geological time scale), in at least three cases (the Deccan, Newark, and Siberian flood basalts), a direct measure of correlation with major extinction events is possible (see graph below). The probability that three major volcanic events that typically last ~1 Myr should occur within 1 Myr of major extinction events during the last 250 Myr (of which there are ~12) is about 10-4. Thinking about the ways in which these two types of global event might be causally linked is a worthy scientific challenge.
This is grim reading. Perhaps the greater super-mega events were triggered by the earth's crust being greatly disturbed by metor or cometary events. The earth's history is the story of a very dynamic system. Thanks to water and living organisms, it is complex, dangerous, beautiful beyond description and more interesting than half of the galaxy. I think (heh).
News of Merapi's activities can now be watched 24/7 by the whole world and you better believe, this bears close watching, too. It is literally life and death. And I am horrified that people are hanging out so close to this volcano. When little Mt. St. Helens blew, many people died who thought they were more then 50 miles away and they could outrun an explosion.
No, you can't. Try 500 miles. Even then, it is possible to be caught.
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