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HOW DO VOLCANIC ERUPTIONS AFFECT THE SOCIETY
Transcript of HOW DO VOLCANIC ERUPTIONS AFFECT THE SOCIETY
HOW DO VOLCANIC ERUPTIONS AFFECT THE SOCIETY
In 1991, mount Pinatubo in the Philippines erupted, and strong winds spread the aerosol particles from the plume around the globe. The result was a measurable cooling of the Earth's surface for a period of almost two years. The role of natural hazards research and developing applications to mitigate the effects of disasters has global implications for reducing loss and saving lives.
Volcanoes affect people in many ways, some are good, some are not. Some of the bad ways are that houses, buildings, roads, and fields can get covered with ash. As long as you can get the ash off (especially if it is wet), your house may not collapse, but often the people leave because of the ash and are not around to continually clean off their roofs. If the ashfall is really heavy it can make it impossible to breathe.
Lava flows are almost always too slow to run over people, but they can certainly run over houses, roads, and any other structures.
Pyroclastic flows are mixtures of hot gas and ash, and they travel very quickly down the slopes of volcanoes. They are so hot and choking that if you are caught in one it will kill you. They are also so fast (100-200 km/hour) that you cannot out-run them. If a volcano that is known for producing pyroclastic flows is looking like it may erupt soon, the best thing is for you to leave before it does. Some of the good ways that volcanoes affect people include producing spectacular scenery, and producing very rich soils for farming.
Water vapor, the most common gas released by volcanoes, causes few problems. Sulfur dioxide, carbon dioxide and hydrogen are released in smaller amounts. Carbon monoxide, hydrogen sulfide, and hydrogen fluoride are also released but typically less than 1 percent by volume.Gases pose the greatest hazard close to the vent where concentrations are greatest. Away from the vent the gases quickly become diluted by air. For most people even a brief visit to a vent is not a health hazard. However, it can be dangerous for people with respiratory problems. The continuous eruption at Kilauea presents some new problems. Long term exposure to volcanic fumes may aggravate existing respiratory problems. It may also cause headaches and fatigue in regularly healthy people. The gases also limit visibility, especially on the leeward side of the island where they become trapped by atmospheric conditions.
The distance you have to evacuate depends entirely on what kind of eruption is going on. For example, Pinatubo, one of the largest recent eruptions sent pyroclastic flows at least 18 km down its flanks, and pumice falls were hot and heavy even beyond that. For example, pumice 7 cm across fell at Clark Air base which is 25 km from the volcano! A 7 cm pumice won’t necessarily kill you but it does mean that there is a lot of pumice falling, and if you don’t get out and continuously sweep off your roof it may fall in and you’ll get squashed.On the other hand, the current eruption at Ruapehu is relatively small. In fact, there were skiers up on the slopes when the eruptions commenced, and even though they were only 1-2 km from the vent they managed to escape. The volcanologists routinely go up on the higher slopes of Ruapehu during these ongoing eruptions to collect ash and take photographs.
So you see, you need to know something about what you think the volcano is going to do before you decide how far to run away. I guess if you have no idea of what the volcano is planning, and have no idea of what it has done in the past, you might want to be at least 25-30 km away, make sure you have a good escape route to get even farther away if necessary, and by all means stay out of low-lying areas!
Many times people think that volcanic eruptions affect the economy through the destruction inflicted upon the landscape during an eruption: lahars and pyroclastic flows destroying bridges and homes, ash ruining crops and water, lava flows overunning communities. However, in Hawai’i, a new effect of volcanism has been seen in the agriculture of the state. The volcanic fog – or “vog” as its called – has been causing major problems with farms on the Big Island of Hawai’i. Since the new activity at Halemaumau (see above) began last year, Kilaeua has been spewing much larger volumes (2-4 times more) of volcanic gases such as sulfur dioxide, carbon dioxide, water and carbon monoxide than in previous years. These gases form a brown fog that is caustic to most animals and plants. The sulfur dioxide, in particular, has caused many crops to fail thanks to the production of sulfuric acid with the sulfur dioxide interacts with water - think of it as a very concentrated version of “acid rain” that is seen in the eastern United States.
The solution to this would either be to build “vog-proof” air-filtering greenhouses or planting a limited set of plants that seem to withstand the effects of the vog. Alternately, one can hope that the gas emissions from Kilaeau will return to lower levels, allowing for the plants to survive. In any of these cases, the growers on the island face a large financial hardship in order to keep their businesses alive in the face of the volcano. This passive destruction of plants by Kilaeua shows how even when a volcano seems to be benign, it can inflict millions of dollars of damage on the local economy.
LET US SEE SOME NEGATIVE
EFFECTS OF VOLCANOES:
♥ Eruptions occurring close to human settlements may spill and destroy lives and property. People often have to be evacuated.
♥ Ash discharged very high into the stratosphere can have negative consequences on the ozone layer.
♠ Landscapes and natural
sceneries can be destroyed.
♠ Ash and mud can mix with rain and melting snow, forming lahars. Lahars are mudflows flowing at very fast pace.
SOME POSITIVE EFFECTS OF
♥ Different types of erupting volcanoes provide extraordinary scenery, so beautiful and natural that they attract tourists to the area, bringing in some economic value.
♥ Places close to volcanic activities tend to have higher potential for geothermal energy, which can be an advantage to the towns and cities.
♥ Some ash and lava breakdown become soils that are rich in nutrients, and become good areas for crop planting activities.
♥ Mel Dianne Tilao
♥ Elailah Novino
♪ Elaisa Novino
♥ Mary Grace Avenido
♥ Kimberly Saguban
♥ Princess Villarin
♥ Zailyn Ruedas