A volcano is a landform (usually a mountain) where molten rock erupts through the surface of the planet. In simple terms a volcano is a mountain that opens downward to a pool of molten rock (magma) below the surface of the earth. It is a hole in the Earth from which molten rock and gas erupt.
The name "volcano" has its origin from the name of Vulcan, a god of fire in Roman mythology. As pressure in the molten rock builds up it needs to escape somewhere. So it forces its way up "fissures" which are narrow cracks in the earths crust. Once the magma erupts through the earth's surface it's called lava.
10. Mount Kelut (May 19, 1919)
Death Toll = 5,115
Kelut is a volcano located in East Java on Java in Indonesia. Like many Indonesian volcanoes and others on the Pacific Ring of Fire, Kelud is known for large explosive eruptions throughout its history. More than 30 eruptions have occurred since 1000 A.D.
On May 19, 1919, an eruption at Kelud killed an estimated 5,000 people, mostly through hot mudflows (also known as "lahars"). More recent eruptions in 1951, 1966, and 1990 have altogether killed another 250 people. Following the 1966 eruption, the Ampera Tunnel was built on the southwestern side of the crater to drain the crater lake and thus reduce the lahar hazard.
09. Santa Maria (October 24, 1902)
Death Toll = 6,000
Santa María Volcano is a large active volcano in the Western Highlands of Guatemala, close to the city of Quetzaltenango. Prior to the Spanish Conquest it was called Gagxanul in the local K'iche' language. Its eruption in 1902 (VEI 6) was one of the four largest eruptions of the 20th century, after the 1912 Novarupta and 1991 Pinatubo eruptions. It is also one of the five biggest eruptions of the past 200 (and probably 300) years.
The first eruption of Santa María in the recorded history occurred in October 1902. Before 1902 the volcano had been dormant for at least 500 years and possibly several thousand years, but its awakening was clearly indicated by a seismic swarm in the region starting in January 1902, which included a major earthquake in April 1902. The eruption began on 24 October, and the largest explosions occurred over the following two days, ejecting an estimated 5.5 cubic kilometres (1.3 cu mi) of magma. The eruption was one of the largest of the 20th century, only slightly less in magnitude to that of Mount Pinatubo in 1991. The eruption had a VEI of 6, thus being 'Colossal'.
08. Laki (June 8, 1783)
Death Toll = 9,350
Laki or Lakagígar (Craters of Laki) is a volcanic fissure situated in the south of Iceland, not far from the canyon of Eldgjá and the small village Kirkjubæjarklaustur, in South-East Iceland. Lakagígar is the correct name as the Laki mountain itself did not erupt, but fissures opened up on each side of it. Lakagígar is part of a volcanic system, centering on the Grímsvötn volcano and including the Thórdarhyrna volcano. It lies between the glaciers of Mýrdalsjökull and Vatnajökull, in an area of fissures which run in a south-west to north-east direction.
On 8 June 1783, a fissure with 130 craters 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 VEI 6 on the Volcanic Explosivity Index, but the eight month emission of sulfuric aerosols resulted in one of the most important climatic and socially repercussive events of the last millennium.
07. Mount Kelut again (November 1586)
Death Toll = 10,000
Again, Mount Kelut is on the list of the most catastrophic volcano eruptions. Back in 1586, Kelut erupted and killed aproximaly 10k people.
06. Mount Unzen (1792)
Death Toll = 15,000
Mount Unzen (Unzendake) is an active volcanic group of several overlapping stratovolcanoes, near the city of Shimabara, Nagasaki Prefecture, on the island of Kyūshū, Japan's southernmost main island.
In 1792, the collapse of one of its several lava domes triggered a tsunami that killed about 15,000 people in Japan's worst-ever volcanic-related disaster. The volcano was most recently active from 1990 to 1995, and a large eruption in 1991 generated a pyroclastic flow that killed 43 people, including three volcanologists.
Unzen's deadliest eruption occurred in 1792, with a large dacitic lava flow coming from Fugendake. The east flank of the Mayuyama dome collapsed unexpectedly following a post-eruption earthquake, creating an avalanche and tsunami that killed an estimated 15,000 people. This remains Japan's worst-ever volcanic-related disaster.
05. Nevado del Ruiz (November 13, 1985)
Death Toll = 23,000
Nevado del Ruiz, also known as El Mesa de Herveo or Kumanday, is the northernmost volcano of the Andean Volcanic Belt, lying about 129 kilometers (80 mi) west of Bogotá in the Tolima Department of Colombia. It is a stratovolcano, composed of many layers of lava alternating with hardened volcanic ash and other pyroclastic rocks. Nevado del Ruiz has been active for about two million years, since the early Pleistocene or late Pliocene epoch, with three major eruptive periods. The current volcanic cone formed during the "present" eruptive period, which began 150 thousand years ago.
Beginning November 1984, geologists observed an increasing level of seismic activity near Nevado del Ruiz. Other signs of a forthcoming eruption included increased fumarole activity, deposition of sulfur on the summit of the volcano, and small phreatic eruptions. In the latter, hot magma came in contact with water, resulting in explosions as the water was almost instantly turned into steam. The most notable of these events was an ash ejection on September 11, 1985. The activity of the volcano decreased in October 1985. The most likely explanation of the events is that new magma rose into the volcanic edifice before September 1985.
At 9:09 pm, on November 13, 1985, Nevado del Ruiz erupted, ejecting dacitic tephra more than 30 kilometres (19 mi) into the atmosphere. The total mass of the erupted material (including magma) was 35 million tonnes - only 3% of the amount that erupted from Mount St. Helens in 1980. The eruption reached a value of 3 on the Volcanic Explosivity Index. The mass of the ejected sulfur dioxide was about 700,000 tonnes, or about 2% of the mass of the erupted solid material, making the eruption atypically sulfur-rich.
The eruption produced pyroclastic flows that melted summit glaciers and snow, generating four thick lahars that raced down river valleys on the volcano's flanks. It also destroyed a small lake that was observed in Arenas crater several months before the eruption. Water in such volcanic lakes tends to be extremely salty and contain dissolved volcanic gases. The lake's hot, acidic water significantly accelerated the melting of the ice; this effect was confirmed by the large amounts of sulfates and chlorides found in the lahar flow.
04. Mount Pelee (May 7 or May 8, 1902)
Death Toll = 29,000
Mount Pelée is an active volcano on the northern tip of the French overseas department of Martinique in the Lesser Antilles island arc of the Caribbean. It is among the deadliest stratovolcanoes on Earth. Its volcanic cone is composed of layers of volcanic ash and hardened lava.
The volcano is now famous for its eruption in 1902 and the destruction that resulted, now dubbed the worst volcanic disaster of the 20th century. The eruption killed about 30,121 people. Most deaths were caused by pyroclastic flows and occurred in the city of Saint-Pierre, which was, at that time, the largest city in Martinique.
On May 8, 1902, Ascension Day, a volcanic eruption destroyed the town of Saint-Pierre, about 6.4 kilometres (4.0 mi) south of the summit.
In the morning, people were observing the fireworks the mountain was displaying. The night shift telegraph operator was sending the reports of the volcano's activity, to the operator at Fort-de-France, claiming no significant new developments; his last transmission was "Allez", handing over the line to the remote operator. It was 7:52; the next second, the telegraph line went dead. A cable repair ship had the city in direct view; the upper mountainside ripped open and a dense black cloud shot out horizontally. A second black cloud rolled upwards, forming a gigantic mushroom cloud and darkening the sky in a 50-mile (80 km) radius. The initial speed of both clouds was later calculated to be over 670 kilometres (420 mi) per hour.
A rush of wind followed, this time towards the mountain. Then came a half-hour downpour of muddy rain mixed with ashes. For the next several hours, all communication with the city was severed. Nobody knew what was happening, nor who had authority over the island, as the governor was unreachable and his status unknown. Some survivors were picked from the sea, mostly badly burned sailors who had been blown into the sea by the blast and then clung for hours to floating debris.
A warship approached the shore at about 12:30, but the intense heat prevented it from landing until about 3 PM. The city burned for several more days.
The area devastated by the pyroclastic cloud covered about 8 square miles (21 km2), with the city of Saint-Pierre taking its brunt.
03. Mount Vesuvius (August 24, 79 AD)
Death Toll = 33,000
Mount Vesuvius (Italian: Monte Vesuvio, Latin: Mons Vesuvius) is a stratovolcano on the Bay of Naples, Italy, about 9 kilometres (5.6 mi) east of Naples and a short distance from the shore. It is the only volcano on the European mainland to have erupted within the last hundred years, although it is not currently erupting. The two other major active volcanoes in Italy, Etna and Stromboli, are located on islands.
Mount Vesuvius is best known for its eruption in AD 79 that led to the destruction of the Roman cities of Pompeii and Herculaneum. They were never rebuilt, although surviving townspeople and probably looters did undertake extensive salvage work after the destructions. The towns' locations were eventually forgotten until their accidental rediscovery in the 18th century.
The AD 79 eruption was preceded by a powerful earthquake seventeen years beforehand on 5 February, 62, which caused widespread destruction around the Bay of Naples, and particularly to Pompeii. Some of the damage had still not been repaired when the volcano erupted. The deaths of 600 sheep from "tainted air" in the vicinity of Pompeii reported by Seneca the Younger leads Sigurdsson to compare them to similar deaths of sheep in Iceland from pools of volcanic Carbon Dioxide and to speculate that the earthquake of 62 was related to new activity by Vesuvius.
02. Krakatoa (August 26-27, 1883)
Death Toll = 36,000
Krakatoa (Indonesian: Krakatau), also spelled Cracatoa or Krakatau, is a volcanic island made of a'a lava 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 island exploded in 1883, killing approximately 40,000 people, although some estimates put the death toll much higher. The explosion is still considered to be the loudest sound ever heard in modern history, with reports of it being heard nearly 3000 miles from its point of origin. The shock wave from the explosion was recorded on barographs around the globe.
On August 27, a series of four huge explosions almost entirely destroyed the island. The explosions were so violent that they were heard 3,500 km (2,200 mi) away in Perth, Western Australia and the island of Rodrigues near Mauritius, 4,800 km (3,000 mi) away. The pressure wave from the final explosion was recorded on barographs around the world, which continued to register it up to 5 days after the explosion. The recordings show that the shockwave from the final explosion reverberated around the globe 7 times in total. Ash was propelled to a height of 80 km (50 mi).
Average global temperatures fell by as much as 1.2 degrees Celsius in the year following the eruption. Weather patterns continued to be chaotic for years and temperatures did not return to normal until 1888.
01. Mount Tambora (April 10, 1815)
Death Toll = 92,000
Mount Tambora (or Tamboro) is an active stratovolcano, also known as a composite volcano, on the island of Sumbawa, Indonesia.
The 1815 eruption is rated 7 on the Volcanic Explosivity Index, the only such eruption since the Lake Taupo eruption in about 180 AD. With an estimated ejecta volume of 160 cubic kilometers, Tambora's 1815 outburst was the largest volcanic eruption in recorded history. The explosion was heard on Sumatra island (more than 2,000 km (1,200 mi) away). Heavy volcanic ash falls were observed as far away as Borneo, Sulawesi, Java and Maluku islands. Most deaths from the eruption were from starvation and disease, as the eruptive fallout ruined agricultural productivity in the local region. The death toll was at least 71,000 people (the most deadly eruption in recorded history), of whom 11,000-12,000 were killed directly by the eruption; the often-cited figure of 92,000 people killed is believed to be overestimated. The eruption created global climate anomalies that included the phenomenon known as "volcanic winter": 1816 became known as the "Year Without a Summer" because of the effect on North American and European weather. Agricultural crops failed and livestock died in much of the Northern Hemisphere, resulting in the worst famine of the 19th century.
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Showing posts with label volcanic eruptions. Show all posts
Showing posts with label volcanic eruptions. Show all posts
Saturday, November 20, 2010
Thursday, November 18, 2010
Earth Changes
Subtle alterations to the geography of the planet could be considered as earth changes. However when talking about the earth and how it will be changing, many people feel that the alterations are going to be large and potentially life ending.
Scientific Confirmation
The scientific community is hesitant to confirm that the planet is undergoing any type of major upheaval. Data collected over the past few decades indicates that earth changes are occurring. Satellite images are sent to computers around the globe offering real time pictures of storms, solar flare and volcanic activity. Computer applications, including weather information, allows people all over the planet to watch and tracks storms of all types.
It has only been a century since people started recording daily temperatures, weather conditions, wind, rain and snowfall amounts. While this information allows scientists to see patterns, data from a hundred years is like a blink of the eye where the planet is concerned. What one scientist may see as a global warming pattern, another may view the same data as confirmation of global cooling. One side of the scientific fence promotes human activity as the cause for severe weather, while the other side staunchly believes these weather patterns are a common cyclic pattern. The only thing that scientists have in common is that they all believe their theories are correct.
Polar Shift
It is a well-known fact that polar shifts have occurred many times since the planet was formed. Ice cores, volcanic sediments and earth core samples have all confirmed that the poles shift every so often. The shortest number of years ever documented between pole shifts was only 5,000. A pole shift occurring a thousand years ago did not affect the human population as it would today. Unlike now, those people used hand tools and communicated through oral and hand written letters. If a pole shift were to occur today, it would cause major earth changes. Nothing electronic would work including telephones, radios, computers and electrical grids. Since there is no written record of how the last pole shift affected migratory birds and animals, scientists can only theorize what the effect will be for them. Keeping additional foods on hand, over the counter medicine and hand tools may be one way to prepare for a pole shift.
Solar Activity
According to the scientific community, our sun is nearing the end of an eleven-year cycle. In the past few months, the sun has been quite active. Solar flares and magnetic storms have swept across the surface of the earth with little to no warnings from the scientific community. Solar flares have classes just like hurricanes and tornados. Class C flares can cause some communication interference and cause the aurora borealis to be brighter and more colorful. Class M flares disrupt communications including satellite feeds, telephones and cell phones. Class X flares can be very destructive shutting down computers and electrical grids. Unfortunately, scientists do not know much about the sun and it can affect the earth. Data is being collected from the sun through the use of space telescopes, un-manned exploration modules and larger more efficient computers that correlate the information collected. Eventually this data will help us understand how the sun can change the lives of those on earth.
Volcanic Activity
Dormant volcanoes around the globe are becoming active. Although hidden from view, underwater volcanic activity has increased as well. The Pacific Ring of Fire, an area in the Pacific Ocean where the sub-oceanic crust is thin, has become more and more active. Yellowstone Park is located over one of the world's biggest magma chambers. The caldera at Yellowstone is big and the ground between the magma chamber and the surface is not very thick. Should the earth's crust become unstable, it is possible that the dormant volcano, that formed the Yellowstone caldera, will become active once again causing severe earth changes.
Earthquakes
Hardly a day goes by without an earthquake being reported. Twenty to fifty years ago, earthquakes were a rarity and even then, they were minor. In the last year, the world has watched Haiti and Chili reel from the affects of unexpected earthquakes. The Chilean quake, which measured 8.8 on the Richter scale, actually moved a town ten feet. Haiti suffered massive devastation from an earthquake that occurred along a previously unknown fault line. Unless there is activity along them, many fault lines go undetected. Even a moderate earthquake in an area that is not expecting one will cause substantial devastation. Earthquakes are events that can change the shape of the earth forever.
Earthquake, volcanic eruptions and severe weather are all types of earth changes. Knowing how to take care of yourself during an emergency and having the supplies on hand to help get you through one will be invaluable.
Original Article
Pat Fisher - Introduced to preparedness, he began learning as much as he could, and now shares that information with you in American Teotwawki
Scientific Confirmation
The scientific community is hesitant to confirm that the planet is undergoing any type of major upheaval. Data collected over the past few decades indicates that earth changes are occurring. Satellite images are sent to computers around the globe offering real time pictures of storms, solar flare and volcanic activity. Computer applications, including weather information, allows people all over the planet to watch and tracks storms of all types.
It has only been a century since people started recording daily temperatures, weather conditions, wind, rain and snowfall amounts. While this information allows scientists to see patterns, data from a hundred years is like a blink of the eye where the planet is concerned. What one scientist may see as a global warming pattern, another may view the same data as confirmation of global cooling. One side of the scientific fence promotes human activity as the cause for severe weather, while the other side staunchly believes these weather patterns are a common cyclic pattern. The only thing that scientists have in common is that they all believe their theories are correct.
Polar Shift
It is a well-known fact that polar shifts have occurred many times since the planet was formed. Ice cores, volcanic sediments and earth core samples have all confirmed that the poles shift every so often. The shortest number of years ever documented between pole shifts was only 5,000. A pole shift occurring a thousand years ago did not affect the human population as it would today. Unlike now, those people used hand tools and communicated through oral and hand written letters. If a pole shift were to occur today, it would cause major earth changes. Nothing electronic would work including telephones, radios, computers and electrical grids. Since there is no written record of how the last pole shift affected migratory birds and animals, scientists can only theorize what the effect will be for them. Keeping additional foods on hand, over the counter medicine and hand tools may be one way to prepare for a pole shift.
Solar Activity
According to the scientific community, our sun is nearing the end of an eleven-year cycle. In the past few months, the sun has been quite active. Solar flares and magnetic storms have swept across the surface of the earth with little to no warnings from the scientific community. Solar flares have classes just like hurricanes and tornados. Class C flares can cause some communication interference and cause the aurora borealis to be brighter and more colorful. Class M flares disrupt communications including satellite feeds, telephones and cell phones. Class X flares can be very destructive shutting down computers and electrical grids. Unfortunately, scientists do not know much about the sun and it can affect the earth. Data is being collected from the sun through the use of space telescopes, un-manned exploration modules and larger more efficient computers that correlate the information collected. Eventually this data will help us understand how the sun can change the lives of those on earth.
Volcanic Activity
Dormant volcanoes around the globe are becoming active. Although hidden from view, underwater volcanic activity has increased as well. The Pacific Ring of Fire, an area in the Pacific Ocean where the sub-oceanic crust is thin, has become more and more active. Yellowstone Park is located over one of the world's biggest magma chambers. The caldera at Yellowstone is big and the ground between the magma chamber and the surface is not very thick. Should the earth's crust become unstable, it is possible that the dormant volcano, that formed the Yellowstone caldera, will become active once again causing severe earth changes.
Earthquakes
Hardly a day goes by without an earthquake being reported. Twenty to fifty years ago, earthquakes were a rarity and even then, they were minor. In the last year, the world has watched Haiti and Chili reel from the affects of unexpected earthquakes. The Chilean quake, which measured 8.8 on the Richter scale, actually moved a town ten feet. Haiti suffered massive devastation from an earthquake that occurred along a previously unknown fault line. Unless there is activity along them, many fault lines go undetected. Even a moderate earthquake in an area that is not expecting one will cause substantial devastation. Earthquakes are events that can change the shape of the earth forever.
Earthquake, volcanic eruptions and severe weather are all types of earth changes. Knowing how to take care of yourself during an emergency and having the supplies on hand to help get you through one will be invaluable.
Original Article
Pat Fisher - Introduced to preparedness, he began learning as much as he could, and now shares that information with you in American Teotwawki
Sunday, May 2, 2010
Climate Change - Volcanic Eruptions & Global Warming
Climate Change - Volcanic Eruptions & Global Warming - What Do Volcanic Eruptions Really Do? |
While we all look on in astonishment at the recent major disruption caused by the Iceland Volcano eruption bellowing its ash cloud high into our skies, there is believe it or not a benefit to be gained from this apparent catastrophe. In reference to Global Warming, volcanic eruptions actually create a cooling effect to the Earth that can reduce climate change, but is the Icelandic volcano eruption big enough?
One such event that climate change gained from was when Mount Pinatubo erupted in the Philippines back in 1991. It is said it reduced the temperature of the Earths' surface by 0.5 degrees Celsius, which offset the greenhouse gases from 1991 to 1993 and a similar event was caused by the Mount St Helens volcanic eruption in Washington USA back in 1980.
This is caused by the volcanic ash particles and sulphur dioxide reaching the stratosphere. There is then a chemical reaction which causes the volcanic particles to create a mirrored effect that reflects the Suns' rays away from the Earth, similar to reflecting the Sun away using a shiny object.
That is of course providing that the ash plume from a volcano is significant enough in dissipating the right quantity of ash and that it reaches the stratosphere. Others such as the Iceland volcanic eruption sometimes only make it into the troposphere where the ash is dispersed over a wide area by very strong winds.
There are volcanic eruptions happening all the time, but it seems you are only aware of them if you live near one or are affected by it erupting. For instance a volcano erupted the same day as the Iceland volcano did, but on the other side of the World in Japan. This was a dormant volcano that has shocked the Japanese, but how many of us either know about it or are affected by it? Very few I suspect.
Article Source: http://EzineArticles.com/?expert=Clive_Anderson
Here's something to think about climate change issues. It is good to know that at least Mount Pinatubo actually reversed for a time climate change issues with regard to global warming trends.
One such event that climate change gained from was when Mount Pinatubo erupted in the Philippines back in 1991. It is said it reduced the temperature of the Earths' surface by 0.5 degrees Celsius, which offset the greenhouse gases from 1991 to 1993 and a similar event was caused by the Mount St Helens volcanic eruption in Washington USA back in 1980.
This is caused by the volcanic ash particles and sulphur dioxide reaching the stratosphere. There is then a chemical reaction which causes the volcanic particles to create a mirrored effect that reflects the Suns' rays away from the Earth, similar to reflecting the Sun away using a shiny object.
That is of course providing that the ash plume from a volcano is significant enough in dissipating the right quantity of ash and that it reaches the stratosphere. Others such as the Iceland volcanic eruption sometimes only make it into the troposphere where the ash is dispersed over a wide area by very strong winds.
There are volcanic eruptions happening all the time, but it seems you are only aware of them if you live near one or are affected by it erupting. For instance a volcano erupted the same day as the Iceland volcano did, but on the other side of the World in Japan. This was a dormant volcano that has shocked the Japanese, but how many of us either know about it or are affected by it? Very few I suspect.
Article Source: http://EzineArticles.com/?expert=Clive_Anderson
Here's something to think about climate change issues. It is good to know that at least Mount Pinatubo actually reversed for a time climate change issues with regard to global warming trends.
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