Tuesday 22 March 2011

Why people wanted to live near Volcanos. - Xinzi.

There are a few reasons why people want to live near a volcano.

Firstly, through some economic reasons, there will probably be a large amount of jobs available in the area created by tourism, like having visitors to the volcano and the surrounding area.

Secondly, there might be volcanoes that create rocks rich in minerals some of which are precious (gold, diamonds etc.) which would create mines, which would make more jobs for the local community. However, these minerals help in other ways as well, because not all of them are mined; some ‘helpful’ minerals are left to help the crops to grow bigger and stronger than crops grown in surrounding counties. This is also good for farmers in the area because they can get more money from their larger crops, which then helps the area’s economy.

Thirdly, the bigger crops would mean more diverse wildlife in the area creating more tourism and jobs for the people of the area, the wildlife would also make a good teaching resource for school in the area, as would the volcano itself. The wildlife/tourism could also turn into a good cycle as well, i.e. more tourism = more conservation efforts for wildlife = more wildlife = more tourism etc.

Also, there is another economic upside of living near a volcano is that geothermal energy is an easily accessible resource and, a very cheap and reliable way to create electricity. This would mean that electricity would be cheaper in the surrounding area and the people would be able to spend more money on the things they want to do, rather than on things like electricity and gas. Hot water would also not be a problem because the volcano would create hot springs from which hot water could be piped into homes and, also surrounding businesses i.e. hotels.

Next, onto some social reasons for living near a volcano. The major thing that people think, having lived near a volcano for most or all of their lives, is that age old saying, ‘It won’t happen to me’. This is often a sentence that forces people to stay where others would have left, because if they have lived next to a volcano for most of, or all of, their lives, then they will be quite content in thinking that it would not erupt in their lifetime. Another thing that fits in with this point is sentimentality. As human beings we get a lot of our feelings from the world around us and also the things we own. So asking someone to leave the place where they grew up just because of a volcano is (perhaps from their point of view) a little unfair.

Lastly, some of the people who live near the volcano may also be superstitious and may read things like horoscopes, which might tell them that they will be safe for as long as they live. Now I am not saying that horoscopes always lie because I have never read one, but I do not think that they can predict when volcanoes are going to erupt.

Monday 21 March 2011

Ways To Reduce The Negative Effects Of Volcanic Eruptions by Jia Rong:)


      You can do many things to reduce the negative effects of volcanic eruptions. The most obvious is not to build towns around a volcano even if the soil around volcanoes are fertile as volcanic eruptions do more harm than good to you. Spraying oncoming lava flow with seawater also helps. This method was proven when it was done in Iceland during an eruption in 1983.
      The government can sent the military to divert the lava flow by bombing at the correct angle and place. These people must be trained and experienced or it might cause more harm than before. You could also use barrier walls to block and penetrate the flow of lava and use diversionary lava channels, so as to change the directions of the lava flow.
       Educate the community about volcanoes, especially focusing on those communities most likely to be affected by the volcanic eruptions. If you are someone who lives near a volcano take extra precautions such as evacuation drills, also take into hand that emergency food and water supplies should be put in the same place so that when there is a need to evacuate it will not take a long time. Do remember that there must be an evacuation plan!
       You can drop large concrete blocks into the tubes feeding the lava so as to divert the flow. You can also cool lava by breaking down the roof and sides of the tube feeding the lava flow. This however has never been tested as when workers went off to start this job, the town that was likely to be affected sent out military personnel to stop the workers.
       You can also dig trenches away from nearby town/villages. Lastly, you can use Hazard Mapping and Satellite Monitoring, so you can tell exactly when the volcano will erupt. Thus, having enough time to evacuate the people from danger and death.

Sunday 20 March 2011

Long-term effects of volcano eruptions by Vivian (;

Lots of people would be left homeless. There would be a massive decline of the country's population due to large amount of casualties from the hot lava and or the suffocating volcanic ash emmited, which is caused by inadequate information on the eruptions.
There will also be effects on the economy, depending on the area effected. If it is the financial district, than the wealth of the country will decrease.

There will also be a huge problem concerning 'Lahar', every time it rains. When the pyroclastic materials mix with large amounts of water, 'lahars' (which is a type of mudflow) are formed, which can flood and bury not only houses but also towns.
The ash and lava that rains over the land and buries it is also a problem. Ash and lava is very difficult to farm on, and it only becomes fertile after a long time.
Therefore, plant life would be limited, which would also affect the food chain.
There might also be silting in the rivers and lakes, which stops boats from navigating through, as the depth becomes much shallower.

Mount Tambora
It created a long-term effect on global climate.
The 150 cubic km of ash that erupted during the explosion not only rained down on the terrestrial surface, but was also projected into the atmosphere, entering the troposphere and, possibly, the stratosphere. The ash covering the Earth’s surface was responsible for lowering many of the plants’ productivity. The ash in the atmosphere only quickened this process, for upon reaching the troposphere and stratosphere it quickly spread, eventually encompassing the entire planet. In turn, the ash particles in the atmosphere reflected incoming solar radiation or absorbed the light waves.

The Tambora volcano in Indonesia erupted in April 1815, but North America and Europe did not notice its effects until months later. In 1816, known as "the year without a summer", gases, ashes and dust arrived over the Iberian Peninsular and reached the stratosphere, where they remained long enough to create "an enormous sun filter".

The period 1812 - 1817 was one of unusually intense volcanic activity. This activity
reached its peak in April 1815, when Mount Tambora (sometimes spelt Tamboro) on the
island of Sumbawa, Indonesia, erupted in one of the most explosive volcanic events of
the last 10,000 years. Although this eruption was much bigger than the 1883 Krakatoa
event, it was less well-documented. Estimates of the size of the eruption vary, although
Christopherson (p 105) quotes one such estimate that 150 cubic km of material was
released. To put this into pespective, this would be 25 times the volume of material
released by the 1980 Mount St. Helens eruption. Before Mount Tambora erupted, it is estimated to have been about 4,000m high. The eruption reduced it to 2851m, and left behind a caldera 7 km across. 

The concussions produced by the explosions are said to have been felt for
1,000 miles all around, and the sound was reported to be heard 1,700 miles distant from
the volcano. In European settlements 200 and 750 miles away the sounds of the eruption
were thought to be cannon fire, and ships and soldiers were despatched to investigate
what were assumed o be attacks on nearby outposts. In Java, some 300 miles west the day
was darkened by the ash, which fell several inches deep. Closer to ground zero, the
rooves of houses 40 miles from the eruption collapsed under the weight of ash. All
vegetation on several nearby islands died, significant masses of pumice were reported in
the ocean off the western coasts of Sumatra, and the immediate area death toll was
around 92,000. 10,000 died from the direct effect of the explosion, lava flows, falling
debris and pyroclastic flows, with another 82,000 dying subsequently through starvation
and disease. The eruption generated an hour long and extremely destructive "whirlwind",
and the sea rose 12 feet above its high tide mark, causing widespread flood damage. It
was 5 years before new vegetative growth returned to the area within 250 miles from the
eruption.




Sources: http://www.sciencedaily.com/releases/2009/02/090225161422.htm
http://www.orangutan.lombok-lintrack.com/mount-tambora-info.htm
http://en.wikipedia.org/wiki/Year_Without_a_Summer
http://www.ehow.com/facts_7184416_mount-tambora-interesting.html
http://en.wikipedia.org/wiki/Mount_Tambora

Saturday 19 March 2011

volcanoes by huiyee point 2=)

There are several things volcanoes do before they erupt: They exhibit anomalous
1) seismic activity,
2) ground deformation,
3) gas emissions
4) thermal emissions.

So scientists monitor changes in these characteristics and try to forecast the likelihood of an eruption. There are usually hours to day to weeks of warning for a volcano. The accuracy varies with volcano - sometimes a volcano shows all the signs of waking up, but then nothing happens. But for volcanoes that are closely monitored, the forecasts are very good and we are getting better at it all the time.

Unfortunately, earthquakes exhibit no known warning signs more than seconds before the quake hits.

A seismometer (or seismograph) is a sensor that detects the intensity of earthquakes caused by magma that is moving. It has been around for almost 2,000 years. The first seismograph was invented by a Chinese scientist. It looked like a large jar with dragon heads on every side. Each dragon had a metal ball in its mouth, and when an earthquake struck, one of the balls would drop into the open mouth of a toad sculpture below. By looking at which ball dropped, Heng (the inventor) said he could tell from which direction the earthquake came. (Actually he couldn't but it was a good guess!)
Luigi Palmieri invented a seismograph in 1856 while working near Italy's Mt. Vesuvias. He wanted a way to predict eruptions, and knew that tremors were usually felt before an eruption. The seismograph uses a pendulum to record movement of the ground below it. The squiggly lines recorded on paper by a seismograph are called a seismogram.
-- Since magma gives off electric currents, electric meters are used tospot rising magma levels by measuring its electric current. Gravimeters can also detect flowing magma.
-- Scientists also take temperatures and gauge gas by using a Landsat satellite. The satellite uses infared sensors to detect temperatures and changes in volcanoes. Aircraft monitors the amount of gas released from the ground. An increase in sulfur dioxide and other gases usually means that there could be volcanic eruptions.
-- The tiltmeter is a sensor that uses a laser beam to find the rising or lowering of magma levels by measuring changes in ground elevation.
-- GPS(Global Positioning System) is a method to determine position of locations on Earth. It uses satellites that broadcast a signal and receivers that pick up and record the signal. GPS uses the relationship between velocity, distance, and time (velocity equals distance divided by time). With GPS, the velocity is the speed of light. Knowing the velocity and time (and the position of the satellite) allows the distance to be calculated. As magma moves up into a volcano the volcano swells and distances between points on the volcano increases (think of dots on a balloon) and the elevation at specific points increases. Such a change is a common occurrence prior to an eruption.
Volcanologists use these instruments to successfully predict eruptions which saves many lives. Scientists are trying to develop new ways to predict future eruptions.