Fossil Evidence that
illustrates how life forms
evolve
Techniques used to
determine geological time
scales
techniques used to learn
about the earth
Impact of Earthquakes
on the Enviroment
Factors responsible for
Earthquakes
Factors responsible for
mountain building
Factors Responsible for
Ocean Ridges
Factors Responsible for
Volcanic Eruptions
Theory of Plate
Tectonics
Impact of Volcanoes
on The Enviroment
Bibliography
Impact of Volcanoes on the Environment
Effects on-atmosphere & climate~ the main effect on weather right near a volcano
is that there is a lot of rain, lightning, and thunder during an eruption, because all the
ash particles that are thrown up into the atmosphere are good at attracting and
collecting water droplets. The lightning is probably caused because it involves
the particles moving through the air and separating positively and negatively charged
particles. For the world-wide affects of volcanic eruptions this only happens when
there are large explosive eruptions that throw material into the stratosphere. If it only
gets into the troposphere it gets removed by rain. The effects on the climate haven't
been completely figured out. It sometimes depends on the size of the particles (mostly
droplets of sulfuric acid). If they are big then they let sunlight in but don't let heat from
the Earth's surface out, and results in the Greenhouse effect. If the particles are smaller
than 2 microns then they block some of the energy coming in from the Sun and the
Earth cools off a little.
Effects on-people~ 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
might not collapse, but a lot of times the people leave because the ash is not continually
cleaned off their roofs and if the ash fall is really heavy it can make it impossible to breathe.
Lava flows are almost always too slow to run over people, but they can 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 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 near you is known for producing pyroclastic flows and looks 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.
Effects on- Plants & animals~ Plants are destroyed over a wide area, during an eruption.
The good thing is that volcanic soil is very rich. Livestock and other mammals have been
killed by lava flows, pyroclastic flows, tephra falls, atmospheric effects, gases, and
tsunami. They can also die from famine, forest fires, and earthquakes caused by or related
to eruptions. 11,000 hares, 6,000 deer, 5,200 elk, 1,400 coyotes, 300 bobcats, 200
black bears, and 15 mountain lions died from the pyroclastic flows of an eruption in 1980.
Water life can be affected by an increase in acidity, increased turbidity, change in
temperature, and change in food supply, these can damage or kill fish. Eruptions can effect
bird migration, roosting, flying ability, and feeding activity. The impact of eruptions on insects
depends on the size of the eruption and the stage of growth of the insect. For example, ash
can be very harmful to wings. The long-term effects of an eruption on wildlife are usually
quite small. It is usually the short-term effects that are really bad. For example, there was
a very big eruption of Santa Maria volcano (Guatemala) in 1902. The eruption itself killed
a few hundred to 1500 people and thousands of birds. Pretty soon there were so many
insects including disease-carrying mosquitoes that eventually 3000-6000 people died from
malaria.
Good things volcanoes do~ The main good effect that volcanoes have on the environment
is to provide nutrients to the soil. Volcanic ash usually contains minerals that are good for
plants, and if it is very fine ash it is able to break down quickly and get mixed into the soil.
Volcanic gases are the source of all the water (and most of the atmosphere) that we have today.
