Thursday, March 13, 2008

Super Eruptions and Climate


Over the winter break I had the opportunity to go on a geology tour and visit a volcano. One of the features I witnessed, was the intrusion of dikes into the monzogranite formation of the area. Coming back to school and starting the geology unit for AP Environmental Science got me thinking about the importance of volcanoes and how they effect the environment. While they can be destructive, are there any benefits to the environment? The blog this week asks students to explore short-term and long-term benefits to the environment of volcanic eruptions.

Questions:
1. What are the characteristics of a volcanic explosion?
2. What are some of the most destructive volcanic explosions in the history of the planet?
3. What is the relationship between volcanoes and climate change throughout history?
4. What are some of the short-term and long-term benefits of a volcanic explosion to the environment? Look at climate, soil, biodiversity, and human agriculture.
5. How did the Toba super eruption effect the evolutionary history of humans?

Resource:
Mystery of the Megavolcano - http://www.pbs.org/wgbh/nova/megavolcano/about.html
* Pay particular attention to the links at the bottom right of this page.
The Genographic Project - http://www.pbs.org/wgbh/nova/megavolcano/about.html
* Pay particular attention to human migrations during the time period of the Toba eruption.
USGS Volcano Hazards Monitoring Program - http://volcanoes.usgs.gov/
* Pay particular attention to the Volcano Monitoring link.

6 comments:

Brittany said...

1. What are the characteristics of a volcanic explosion?
Volcanic explosions typically spew a large amount of gas, dust, ash, and lava fragments out of a central crater. Oftentimes, a dense cloud of ash-laden gas rises high above the peak. The hot molten rock and lava flows down the cone and then cools to form more volcanic wall.
2. What are some of the most destructive volcanic explosions in the history of the planet?
Mt. Tambora, Indonesia (1815) – killed 92,000, starvation afterwards
Karkatoa, Indonesia (1883) – killed 36,417, tsunami
Mt. Pelee, Martinique (1092) – killed 29,025, pyroclastic flows
Nevada del Ruiz, Colombia (1985) – killed 23,000, mud flow
Unzen, Japan (1792) – 14,300, cone collapse, tsunami

3. What is the relationship between volcanoes and climate change throughout history?
High magnitude volcanic eruptions impact global climate by reducing the amount of solar radiation reaching the Earth’s surface, lowering temperatures in the troposphere, and changing atmospheric circulation patterns. Even though the actual eruption only lasts a few days, the outpouring of gasses and ash can influence climate patterns for years by scattering incoming solar radiation, called “radiative forcing.”

4. What are some of the short-term and long-term benefits of a volcanic explosion to the environment? Look at climate, soil, biodiversity, and human agriculture.
Volcanoes provide very rich nutrients for the soils and make rich farmland. In areas of heavy rainfall where the soil is depleted quickly the volcanos are able to replenish nutrients and carbons and phosphates. Also, volcanoes provide beautiful scenery and numerous legends and myths that add culture to various people. Volcanoes are also a good source of geothermal energy to power hoses from the heat of the earth. Also, volcanic eruptions can form islands (like Hawaii) where new life can form and evolve.

5. How did the Toba super eruption effect the evolutionary history of humans?
The Toba explosion caused a bottle-neck of human evolution, decreasing the total population and altering the gene pool. After the eruption, dramatic global cooling caused a 6-year global winter which many humans were unable to survive. Only those with more advanced tools and knowledge were able to continue evolving and spread their genes to the later generations.

leigha said...

1. What are the characteristics of a volcanic explosion?
Volcanic explosions include gas, ash, dust in the air and lava covering the area around the volcano. The thick clouds of gas in the air cover the surrounding area and the sulfur causes the air to cool. The molten rock covering the ground eventually cools and forms solid land. Many times these volcanoes, over time, form islands and land.

2. What are some of the most destructive volcanic explosions in the history of the planet?
1815 explosion of Tambora volcano on Sumbawa island in Indonesia (the next year there was no summer) 92,000 killed, 80,000 after from starvation
Karkatoa, Indonesia Aug. 26, 1883 36,417 killed 90% killed by a tsunami
Mt. Pelee, Martinique Aug. 30, 1902 29,025 killed mainly because of Pyroclastic flows
Nevada del Ruiz, Colombia Nov. 13, 1985-23,000 killed mainly because of Mud flow
Unzen, Japan 1792-14,300 killed 70% killed by cone collapse; 30% by a tsunami

3. What is the relationship between volcanoes and climate change throughout history?
Solar radiation is affected by volcanoes. The amount of solar radiation decreases and therefore changes the global climate. The temperature in the troposphere is lowered, and therefore the atmosphere’s circulation is affected. Many times volcanoes lower temperature in the surrounding area, and although we only feel the effects for a few days, the affects will change climate eventually over the years permanently.

4. What are some of the short-term and long-term benefits of a volcanic explosion to the environment? Look at climate, soil, biodiversity, and human agriculture.
Volcanoes help the soil around it because the lava gives off rich nutrients that help farming and grazing. Volcanoes replenish soil with phosphates and carbons. Also, lava rocks can be used in roads, and pumice is used for grinding and polishing metals and other materials. Volcanic ash improves soil fertility and underground steams volcanoes produce can be used as an alternative source of energy. Also, volcanoes can be used as “windows” to the inside of the earth; therefore, scientists can understand the earth’s internal structure better.

5. How did the Toba super eruption affect the evolutionary history of humans?
The Toba super eruption cause human evolution to bottle-neck. The eruption decreased the population and therefore distorted the gene pool. After the eruption, survival of the fittest set it, and only those that had knowledge of the earth and life and skills that could protect them against the cold climate change. Because many people died from the secondary effects of the eruption, the amount off babies being produced also decreased. Many of the babies that were born around this time also could not be protected from the difficult weather patterns, so they were eliminated. If the volcano had not erupted, they could have lived through that period of time.

Eric said...

1. What are the characteristics of a volcanic explosion?

Volcanic explosions shoot large amounts of dust, gas, ash, and lava debris out of a hole in the center. Usually a cloud of ash-laden gases will rise high above the peak and can be seen for miles. Then hot molten rock and lava flows down the side of the volcano and then cools to create a bigger volcano.

2. What are some of the most destructive volcanic explosions in the history of the planet?

Mt. Tambora, Indonesia April 5, 1815 92,000 12,000 directly by the volcano; 80,000 from starvation afterward

Karkatoa, Indonesia Aug. 26, 1883 36,417 90% killed by a tsunami

Mt. Pelee, Martinique Aug. 30, 1902 29,025 Pyroclastic flows

Nevada del Ruiz, Colombia Nov. 13, 1985 23,000 Mud flow

Unzen, Japan 1792 14,300 70% killed by cone collapse; 30% by a tsunami


3. What is the relationship between volcanoes and climate change throughout history?

At first, large volcanic eruptions cause an increase in temperature. Later, global climate becomes colder because of the large cloud of ash and gas that covers the sky reducing the amount of solar radiation that reaches the Earth’s surface. This lowers temperatures and changes atmospheric circulation patterns.

4. What are some of the short-term and long-term benefits of a volcanic explosion to the environment? Look at climate, soil, biodiversity, and human agriculture.

The lava from the volcano provides very rich nutrients for the soil. Volcanoes are also a good source of geothermal energy to power geothermal plants with the heat of the earth. Lava rocks can also be used as materials in roads, and the pumice from the volcanoes is used for grinding and polishing metals.

5. How did the Toba super eruption effect the evolutionary history of humans?

The Toba explosion caused a decrease in the total population and altered the gene pool due to the decrease. The secondary effect of global cooling caused a 6-year global winter which many humans were unable to survive. This reduced the variety of genes that were around.

Courtney said...

1. What are the characteristics of a volcanic explosion?

The characteristics of volcanic explosion are as follows. The pressure of the earth’s core increases which causes the magma to rise in temperature. It then travels up the conduit (pipe) and out the top of the volcano, which is also referred to as the vent. At times there can be multiple vents which magma may flow out of, it does not just have to flow out of the main vent or crater. Magma can also escape into branch pipes and then rest in small places called sills. Once the magma hits the open air, ash clouds can begin to form and depending on the wind pattern can be scattered for miles. As the lava flows outside of the chamber, it creates layers, which build up over time and increase the size of the mountain. This also happens with the ash that falls from the ash cloud.

2. What are some of the most destructive volcanic explosions in the history of the planet?

Some of the most destructive volcanic explosions in history are Mount St. Helens in Washington, Mount Rainier in Washington, and Mount Vesuvius in Italy.

3. What is the relationship between volcanoes and climate change throughout history?

During the eruption of a volcano, toxic gases are released into the air preventing radiation from the sun from entering into the earth’s atmosphere. Therefore the temperature of the earth will decrease and the climate will change to a cooler climate over time, especially if there are multiple volcanic eruptions over a specific period of time. The affects of a volcano can be much longer than people think. It is not just during the time that the volcano is erupting but for long after that. The affects of the volcanic eruption can be felt for years.

4. What are some of the short-term and long-term benefits of a volcanic explosion to the environment? Look at climate, soil, biodiversity, and human agriculture.

The short-term benefits of a volcanic explosion are such things as the nutrient rich ash that is spread because of the ash clouds. Long-term benefits include such things as the creation of islands from the eruption of the volcano.

5. How did the Toba super eruption affect the evolutionary history of humans?

The Toba super eruption created one of the biggest alterations in human existence. The explosions wiped out a large percentage of the human population while lowering the climate temperature. This created many years of frigid weather, which changed the way life existed on earth. Not only did humans have to adjust to this temperature, so did plants and animals.

Colin K. said...

1. What are the characteristics of a volcanic explosion?
When the volcano erupts, lava, ash, dust, and hot gas can come out of the top of the volcano. Volcano eruptions can lead to lateral blasts, lava flows, hot ash flows, mudslides, avalanches, falling ash and floods. Also it can make way for tsunamis, flashfloods, earthquakes, mudflows and rockfalls to happen.
2. What are some of the most destructive volcanic explosions in the history of the planet?
-Tambora, Indonesia in 1815 and 92,000 died
-Krakatau, Indonesia in1883 and 36,417 died
-Mount Pelee, Martinique in 1902 and 29,025 died
-Ruiz, Colombia in 1985 and 25,000 died
-Unzen, Japan in 1792 and 14,300 died
3. What is the relationship between volcanoes and climate change throughout history?
The relationship between volcanoes and climate change throughout history is direct and can last more than just a couple of day (in fact even years). The volcano’s eruption affects the climate by reducing the amount of solar radiation, altering atmospheric patterns, and lowering the temperatures in the earth’s troposphere.
4. What are some of the short-term and long-term benefits of a volcanic explosion to the environment? Look at climate, soil, biodiversity, and human agriculture.

Volcanoes can give farmers and farmland a great boost. They provide extremely rich nutrients that are found in their soil. Volcanoes provide a scenic change as well to the landscape around it. They can be used as a source of geothermal energy also. And even though it is said to not be around for much longer, Hawaii was formed by a series of volcanoes.

5. How did the Toba super eruption affect the evolutionary history of humans?
The Toban explosion affected the evolutionary history of humans by altering and changing their gene pool and destroying a majority of the human population. So, like Darwin said, only the strongest after that survived. The earth went through a 6 year winter stage and only the strongest survived.

Anonymous said...

3. What is the relationship between volcanoes and climate change throughout history?

The relationship between volcanoes and climate change is that volcanoes changes the temperature of the earth since volcanic ash blocks out the sun and doesn't let solar radiation through. This relationship is termed volcanic winters.