Saturday, 12 December 2015
Friday, 31 July 2015
Thursday, 23 July 2015
The Pacific Ring Of Fire
What is Pacific ring of fire? How the volcanoes are formed? The Pacific ring of fire is a horseshoe shaped and is a boundary of the Pacific plate where almost dangerous active volcanoes are located. And it is an area where almost geological events occur like powerful volcanic eruptions, frequent earthquake and tsunamis. The Ring of Fire stretches from New Zealand all the way across the coast of North and South America. There are more than 450 active and dormant volcanoes located within the Ring of Fire.
Volcanoes are formed because of these 2 theories that scientists believed. The first theory is the Plate tectonic theory wherein scientists believed that the internal heat from the earth needs to escape and the heat goes up to the crust. And when the heat goes up to the crust, the heat breaks the plates apart at the spreading centers and it creates a movement called subduction. Subduction is a convergent movement whereby dense ocean plates collide with and slide under the lighter continental plates. As the seafloor along with the Carbon 12 slides continuously on the continental plates, the rocks in it melts and forms a magma that needs to escape and find vents. Researchers finds an evidence that subduction really happens just like the Carbon 12. This material can only be found on dead animals on the seafloor just like Phytoplankton’s. The second theory is the Hot spots wherein scientists believed that Hot spots are areas deep within the Earth’s mantle from which heat rises. This heat facilitates the melting of rock in the brittle, upper portion of the mantle. The melted rock, known as magma, often pushes through cracks in the crust to form volcanoes.
With the formation of volcanoes, there are natural calamity occurs in the Pacific ring of Fire. The majority of Earth’s earthquakes occur in the Ring of Fire, too. These earthquakes are caused by the lateral or vertical movement of rock along plates. About 81% of the world’s largest earthquakes have occurred along the Ring of Fire. And also, Almost 80 percent of tsunamis occur within the Pacific Ocean’s ‘Ring of Fire’. This is due to the amount of earthquake and volcanic activity in the area, which occur due to the tectonic shifts in the earth’s plates.
Therefore, I conclude that the Pacific Ring of Fire is an area where safety first is a must because Volcanic eruption , tsunamis, and Earthquakes occur in this place. The volcanoes all around the world not only in the Pacific ocean are difficult to form but when it forms, millions and millions of live are lost because of these things. That’s why different government in the countries that surrounding the Pacific Ocean also the other countries that are away of the Pacific Ocean are getting ready for natural disasters might occur in the near future. We should not depend on the safety preparedness of the government but we too should be prepared also in time of these natural calamities.
Monday, 29 June 2015
TOP 10 MOST DANGEROUS VOLCANIC ERUPTIONS
10. Ulawun, Papua New Guinea
Ulawun is the classic cone shaped volcano with its smoking peak rising up out of the jungle. But it isn’t just jungle surrounding this active volcano, there are also several thousand people living within the vicinity.
Known locally as the “Father”, Ulawun is Papua New Guinea’s most active volcano and probably the most dangerous. One of the major risks posed by the volcano is slope failure. Given its height some have suggested it may be relatively unstable meaning an eruption could result in massive landslides which would devastate the surrounding area and result in the loss of many lives.
But it isn’t just the possibility of Ulawun erupting that is a reason to be wary of this volcano. It is estimated that Ulawun belches out almost 2% of all the world’s sulphur dioxide, a noxious pollutant.
9. Popocatepetl, Mexico
Not only is the snow-capped Popocatépetl the second highest mountain in Mexico, it is also a highly active volcano. What is most alarming about this enormous, smoke and fire belching stratovolcano is its proximity to the Mexican capital. Popocatépetl is only 70 km (40 mi) from Mexico City which is home to 18 million people. But it gets worse; the city of Puebla which is home to 2 million people is even closer. A major eruption here would be catastrophic with molten lava and mudslides flowing into the surrounding valleys and millions within the blast radius.
During the last 500 years there have been more than 15 major eruptions of Popocatépetl with the most recent in 1947. So there is plenty of previous form. Whilst things were relatively quiet activity seems to have picked up over recent years with rumblings in 2000 sparking a mass evacuation and any number of small eruptions since.
8. Mauna Loa, Hawaii
Mauna Loa is purported to be the largest active volcano on Earth. There is more lava bubbling away under this behemoth than any other volcano. Mauna Loa’s size is not entirely obvious from the 4,170 m (13,680 ft) peak but when you take into account that it rises up from the sea floor it is actually taller than Mount Everest.
As a shield volcano Mauna Loa is a bit of a gentle giant. Instead of exploding dramatically these volcanoes tend to spew out constant streams of magma forming shallow slopes. These lava flows are generally slow moving and possess little danger, except to property.
So why, I hear you ask, is Mauna Loa on this list of the World’s most dangerous volcanoes? Well, there is a Doomsday scenario. This huge volcano has grown rapidly of the millenia and there may be deep fault lines within the slopes of this sea mountain. A collapse and resulting massive landslide could cause a megatsunami. That’s right, a mega-tsunami! You may think this far-fetched but there is geological evidence of this sort of collapse 100,000 years ago causing a 1,000 ft (300 m) wave which piled into the island of Lāna`i. If the same were to happen at Mauna Loa, a tsunami would arrive in Honolulu within 30 minutes reaching as far as 16 miles (22 km) inland.
7. Yellowstone Caldera, USA
Now, the Yellowstone Supervolcano is a tricky one. It might be best placed at the top of this list or not on the list at all, nobody seems to know for sure. Given what it is and previous form the potential is pretty terrifying – think something along the scale of a nuclear war. Many of the largest volcanic eruptions ever took place in this region including one that was equivalent to a 250,000 megaton explosion – that’s over 1,000 times bigger than Krakatoa. During this eruption 1,200 cubic miles (5,000 km3) of rock was ejected, enough to fill Lake Michigan. What is more, so mush ash would be created that the entire USA would have been buried under a 10 feet (3 m) carpet making it uninhabitable, whilst the rest of the world would be starved of sunlight for months.
Fortunately, this all happened 27 million years ago.
Fortunately, this all happened 27 million years ago.
Today the caldera measures around 40 miles (60 km) across, but it is what is underneath that gives cause for concern. It is estimated that there is a magma chamber measuring 50 miles (80 km) long and 12 miles (20 km) wide lurking beneath Yellowstone. That is huge, and is certainly on the supervolcano scale. However, whilst some media sources have claimed the next supereruption is now overdue scientists seem to dismiss this stating that such events are neither “regular or predictable”.
6. Sakurajima, Japan
Sakurajima in southern Japan is sometimes referred to as the “Vesuvius of the East” on account of its highly active nature. The similarities don’t end here either; located just a few miles away is the city of Kagoshima which is home to nearly 700,000 people. If there is a city anywhere that has prepared itself for the danger of an imminent volcanic eruption then it is Kagoshima. There are regular evacuation rehearsals and the city even has volcano shelters.
But this isn’t just for fun. Sakurajima is constantly throwing out columns of ash high into the atmosphere with thousands of minor explosions every year. So active is the volcano that it is one of only three volcanos to be placed on Level 3 (orange) alert. This means don’t get too close.
In a recent daytime eruption so much ash was ejected that it threw the Kagoshima city into darkness. However, this was nothing compared to an eruption in 1914 in which the former mountain island spewed out so much lava that it became part of the mainland.
Whilst on the subject of Japan it is worth pointing out that the iconic Mount Fuji is not just the country’s highest mountain, but an enormous volcano within 60 miles (100 km) of Tokyo…
5. Galeras, Colombia
If it is possible for a volcano to have a sense of irony Galeras in Colombia is such a volcano. In 1993 there was a conference on the world’s most dangerous volcanoes in the city of Pasto, at the foot of Galeras. Several of the scientists at the conference decided to take a closer look at the crater of Galeras at which point the volcano unexpectedly erupted killing six scientists and three tourists.
Galeras is the most active volcano in Colombia and has a erupted violently on several occasions in the past 500,000 years. Given that the city of Pasto, with its population of nearly half a million, is so close, it is little surprise that Galeras is categorised as a Decade Volcano.
Despite the devastating potential of Galeras it is another volcano in Colombia that has wrought the most destruction in recent times. On November 13, 1985, a minor eruption of Nevada del Ruizcaused a massive lahar (a landslide of ice and mud) to thunder through the surrounding river valleys destroying everything in their wake. This included the town of Armero with its population of 29,000. Despite the government having received warnings to evacuate the area this was not passed on. When the wall of debris slammed into the town it killed 20,000 people. Several thousand more were killed in the surrounding areas.
4. Mt. Merapi, Indonesia
About half of the 20 deadliest volcanic eruptions in history have happened in Indonesia including one which almost wiped out the human race. Krakatoa was one of these but barely made it into the top ten. So it is among this illustrious company that we have chosen Mount Merapi (“Mountain of Fire”) on the island of Java as the most potentially dangerous.
Merapi is certainly the most active volcano in Indonesia sitting on the Pacific Ring of Fire; belching smoke most days this volcano has erupted with deadly consequences at least twice in the last ten years. Historically there have been some huge eruptions at Merapi. One allegedly covered the whole of Java in ash whilst another has been cited as wiping out the Hindu Kingdom of Mataram.
The volcano has been erupting regularly for around the last 500 years with significant and violent eruptions every 10 to 15 years. This was the case in 2010 when despite 20,000 people being evacuated the death toll reached 353 and thousands of homes were destroyed.
In 1930 things were much worse when more than ten villages were wiped out by lava flows killing at least 1,400 people.
The volcano has been erupting regularly for around the last 500 years with significant and violent eruptions every 10 to 15 years. This was the case in 2010 when despite 20,000 people being evacuated the death toll reached 353 and thousands of homes were destroyed.
In 1930 things were much worse when more than ten villages were wiped out by lava flows killing at least 1,400 people.
It is these lava (pyroclastic) flows that make Merapi particularly dangerous flowing extremely rapidly and reaching out many miles from the peak. In the event of a really major eruption the city of Yogyakarta 17 miles (28 km) away would be at serious risk.
3. Mount Rainier, USA
Mount Rainer has much in common with Popocatépetl in Mexico. Both are massive, steep-sided stratovolcanoes and both are members of the exclusive “Decade Volcano” club, a list of 17 volcanoes that are considered particularly dangerous due to their proximity to centers of population and their history of destructive eruptions. This active volcano sits close to many small towns and cities including Seattle which is only 54 miles (87 km) away.
Rainer is the tallest mountain in Washington state with a prominence of 13,211 feet (4,027 m) – this is the height of the mountain alone. That’s bigger than K2, the world’s second tallest mountain.
Out of all the Decade volcanoes it is Mount Rainer that tops the list as the most potentially deadly. But it isn’t just the enormous size of Mount Rainer that makes it such a potential danger. The major threat from the volcano is the massive amount of ice trapped in glaciers on its slopes. It is hard to imagine how much ice we are talking about here but suffice to say it is enough to feed six substantial rivers.
Out of all the Decade volcanoes it is Mount Rainer that tops the list as the most potentially deadly. But it isn’t just the enormous size of Mount Rainer that makes it such a potential danger. The major threat from the volcano is the massive amount of ice trapped in glaciers on its slopes. It is hard to imagine how much ice we are talking about here but suffice to say it is enough to feed six substantial rivers.
If Mount Rainer erupted, in addition to lava it is likely these vast amounts of ice locked up the volcano would come cascading down the river valleys. These giant avalanches of ice and rock (known as lahars) would annihilate all in their path possibly reaching as far as Lake Washington or Puget Sound. If this happened tsunamis might be unleashed causing devastation to areas of Seattle.
The good news is no significant activity has been recorded in the last five years. In addition, warning systems and evacuation plans would hopefully avert major loss of life.
2. Mount Nyiragongo, Democratic Republic of Congo
Mount Nyiragongo has the classic cone shape associated with stratovolcanoes. At the top of its steep slopes is a 1.5 mile (2 km) wide crater which is filled with boiling lava. This lava lake varies in depth with time but has been estimated to reach around 2,000 (600 m) feet deep. In effect Nyiragongo is a massive cauldron of molten rock.
Someone else can do the math about how much lava that is but it doesn’t take a genius to figure out that it probably isn’t good to have a city of over a million people less than 10 miles (15 km) away. However, that’s exactly were the city of Goma is.
Someone else can do the math about how much lava that is but it doesn’t take a genius to figure out that it probably isn’t good to have a city of over a million people less than 10 miles (15 km) away. However, that’s exactly were the city of Goma is.
Unlike the slow moving lava flows of the shield volcanoes in Hawaii the lava at Nyiragongo moves fast. When in 1977 the crater walls gave way lava spewed out at a over 60 miles per hour (100 kph) annihilating several villages as it went. In a more recent eruption (2002) lava flows reeked a trail of destruction through the middle of Goma. A 600-300 ft (200-1000m) wide river of lava ran through the city destroying over 4,500 buildings in its path.
Despite the damage to property the evacuation of 400,000 people meant that relatively few lives were lost. 147 people were killed though, mostly from asphyxiation due to the release of suffocating carbon dioxide gas.
Despite the damage to property the evacuation of 400,000 people meant that relatively few lives were lost. 147 people were killed though, mostly from asphyxiation due to the release of suffocating carbon dioxide gas.
1. Mount Vesuvius and the Phlegraean Fields, Italy
The eruption of Mount Vesuvius in 79AD is one of the most well known in all of history. It embodies everything we fear in volcanoes and left a reminder for future generations. When Vesuvius erupted at around midday on August 24th it did so with the force of 100,000 atomic bombs. Molten rock and pumice ash were ejected from the mountain at the rate of 1.5 million tons per second. Much of this rained down on the nearby cities of Pompeii and Herculaneum killing thousands instantly and preserving them in suspended animation under a thick carpet of ash only to be discovered over a thousand years later.
Two thousand years on and Vesuvius is very much an active volcano with at least two significant eruptions. Perhaps the biggest difference now though is the 3 million people living in the vicinity of Mount Vesuvius, particularly in the densely populated city of Naples. This alone would be a good reason why Vesuvius tops the list of dangerous volcanoes, but no, it gets worse!
On the western edge of Naples are the Phlegraean Fields. Translating as “burning fields” this is an area of intense geothermal activity with various displays of bubbling mud, sulfurous belching and the likes. What the Phlegraean Fields are in fact is a vast caldera similar to the “Super Volcano” that lies beneath Yellowstone. Along with the similarities there is also the massive difference that this is underneath a major city.
It is estimated that the volcano here is capable of producing a VEI 7 eruption – that’s ten times greater than Krakatoa. Monitoring of the caldera is fairly intense, as it would have to be to make sure that more or less one million people in the immediate area were safely evacuated should the need arise.
It is estimated that the volcano here is capable of producing a VEI 7 eruption – that’s ten times greater than Krakatoa. Monitoring of the caldera is fairly intense, as it would have to be to make sure that more or less one million people in the immediate area were safely evacuated should the need arise.
Saturday, 27 June 2015
Earth Science
Earth Science is the study of the Earth and its neighbors in space. It is an exciting science with many interesting and practical applications. Some Earth scientists use their knowledge of the Earth to locate and develop energy and mineral resources. Others study the impact of human activity on Earth's environment and design methods to protect the planet. Some use their knowledge about Earth processes such as volcanoes, earthquakes and hurricanes to plan communities that will not expose people to these dangerous events.
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