Did you know that Yellowstone National Park, United States of America? It is actually an active super volcano? As we walk around the park we may think: “I don’t see any volcanoes’’. That is because much of the entire park is a volcano. The bubbling geysers and hot springs are an indication of the churning activity below the surface…if erupted, has the potential to wipe out the majority of the United States of America.   

Important source of life

Volcanoes are caused when molten rock (magma) flows out on to the earth’s surface through fissures that are caused due to the movement of plates. Volcanoes are generally found where tectonic plates are diverging or converging. The fissures, through which the magma comes out on to the crust of the earth is known as vent. The rocks and other material which come on to the surface of the earth from the interior of the earth accumulate to develop volcanic mountains. The funnel shaped depression that can be seen on the summit of a volcano is known as a crater.

 TYPES OF VOLCANOES

Based on the chances of eruption the volcanoes are classified into three:
1) Active Volcanoes:-Those that frequently erupt. For example: Mount Etna in Italy.
2) Extinct Volcanoes:-Active at a time. But will not erupt again. For example: Mount Buninyong in Australia.
3) Dormant Volcanoes:- Those that have erupted earlier and not active in the recent past. But can become active. For example: Vesuvius in Italy.

VOLCANOLOGY

Volcanology (Vulcanology) is the study of volcanoes, lava, magma and related geological, geophysical and geochemical phenomena.

VOLCANOLOGIST

A volcanologist is a highly educated specialist in geophysics who studies active and inactive volcanoes.

INDIA’S ONLY
ACTIVE VOLCANO

Barren Island, one of the most easterly of the Andaman Islands, is the only confirmed active volcano in India. The first recorded eruptions of the volcano dates back to 1787. Since then, the volcano has erupted more than ten times.

TEN MOST ACTIVE
VOLCANOES
IN THE WORLD

1)Mount Vesuvius, Italy, 2)Popocatepetl, Mexico, 3)Sakurajima, Japan, 4)Galeras, Columbia, 5)Mount Merapi, Indonesia, 6)Mount Nyiragongo, Congo, 7)Ulawun, Papua New Guinea,8)Taal Volcano, Philippines, 9)Mauna Loa, Hawaii,10)Santa Maria, Guatemala.

HELPFUL IN MANY WAYS

Though volcanic eruptions are threats to human life, the areas where the eruptions have taken place are useful too:
1) Volcanic gases are the main source of all the water that we have today.
2) Another good effect that volcanoes have on the environment is to provide nutrients to the surrounding soil. For example, the most of Italy has poor soils with bare limestone rock. But the regions around Naples, the site of Mount Vesuvius, are covered in very rich soil that was deposited in two huge volcanic eruptions. This area is planted with grape vines, vegetables and flowers that grow very well.
3) The black soil that formed as a result of a volcanic eruption is very suitable for cotton cultivation.
4) These areas are rich in minerals.
 5) These areas have been developed as well known tourist spots.
6) Another benefit might be the fact that volcanic slopes are often rather inaccessible, especially if they
   are steep. Thus they can provide refuges for rare plants and animals.
7) Volcanoes make islands and add to the continents. For example, the entire Hawaiian Chain of Islands was created by the constant eruptions of a single volcanic hot spot. Unique species of plants and animals evolved into new forms on these islands, creating balanced ecosystems.

VOLCANOES AND CLIMATE

Volcanologists believe that the balance of the earth’s mild climate over periods of millions of years is maintained by ongoing volcanisms. Volcanoes affect the climate through the gases and dust particles thrown into the atmosphere during eruptions. The effect of the volcanic gases and dust may warm or cool the earth’s surface, depending on how sunlight interacts with the volcanic material. Tiny dust-size ash particles thrown into the lower atmosphere will float around for hours or days, causing darkness and cooling directly beneath the ash cloud, but these particles are quickly washed out of the air by the abundant water and rain present in the lower atmosphere. However, dust tossed into the dry upper atmosphere, the stratosphere, can remain for weeks to months before they finally settle. These particles block sunlight and cause some cooling over large areas of the earth.

WATER AND
CARBON DIOXIDE

Volcanoes release large amounts of water and carbon dioxide. When these two are in the form of gases in the atmosphere, they absorb heat radiation emitted by the ground and hold it in the atmosphere. This causes the air below to get warmer.

SULFUR COMPOUNDS
Volcanoes that release large amounts of sulfur compounds like sulfur oxide or sulfur dioxide affect the climate more strongly.

HOW ARE VOLCANOES
AND EARTHQUAKES
RELATED?

Some, but not all, earthquakes are related to volcanoes. For example, most earthquakes are along the edges of tectonic plates. This is where most volcanoes are too. However, most earthquakes are caused by the interaction of the plates not the movement of magma. Remember, the ground around the volcano is not secure and can cause big earthquakes.

VOLCANIC ERUPTIONS
GENERATE TSUNAMIS

A tsunami is a huge sea wave, or also known as a seismic sea wave. The most common cause of tsunamis is earthquakes. But volcanoes can also cause tsunamis. Volcanic tsunamis are not as common as earthquake tsunamis but when they do happen, their effects will be terrible.

WHAT OTHER EFFCTS
DO VOLCANOES CAUSE?

Volcanic eruptions can cause fast floods, mud slides and rock falls. Lava can travel very far and burn, bury or damage anything in its path, including people, houses, trees, etc.