Volcanoes: An Overview of Fiery Wonders

Volcanoes are geological landforms, or openings in the Earth’s crust that ejects lava, ash, and gases. Most volcanoes are in the form of a mountain, such as Mt. St Helenslocated in Washington State. The Earth contains numerous volcanoes located on many different continents. Most volcanoes go unnoticed because of little activity, whereas other volcanoes have made a name for themselves in history books. Volcanoes tend to occur by the borders of continental plates. Moreover, volcanoes are not limited to the Earth’s surface. Astronomers and scientists have concluded that volcanoes appear to exist on other planets and moons within our solar system. Volcanoes, which are named after the mythological god of fire, come in many different forms.

Types of Volcanoes

Volcanoes are classified based on the material that erupts. If the magma contains a high amount of silica, the lava is felsic. On the other hand, magma including small amounts of silica is termed mafic. Acidic and basic are more common terms used to describe felsic and mafic volcanoes. The five types of volcanoes include:

Shield Volcanoes. These mountains emit massive quantities of lava and steadily shape a mountain into a shield-like appearance. The lava from shield volcanoes is extremely hot and liquefied. The liquid contributes to the lava flowing for several miles after eruption. These mountains are common in Hawaii and . In fact, the largest shield volcano on Earth is 9,000 meters high, and situated on the sea floor of Hawaii’s Mauna Loa Island.

Cinder Cones. These volcano mountains primarily erupts small pieces of rock formation that collects near the vent. Eruptions of this sort have a short duration and forms a cone shaped hill. Moreover, volcano cones are relatively small. Their height ranges from 30 meter to 300 meters high.

Stratovolcanoes. These volcanoes, which are located in , , , and Antarctica, are tall mountains compiled of hardened lava flow and expelled objects. Stratovolcanoes are commonly steep mountains. Well-known stratovolcanoes include Mt.
Fijiin , and Mt. Vesuviusin .

Supervolcanoes. These large volcanoes erupt with massive energy. The power behind a supervolcanoes eruption is enough to significantly alter landscapes, weather patterns, and completely devastate a continent. Researchers and scientists have devoted much time and energy to studying supervolcano eruptions. In the wake of the

Indian Oceantsunami in December 2004, much concern has been placed on colossal devastation by a natural disaster. Still, many are skeptical as to whether a supervolcano eruption will actually occur. One theory suggests that the earth experienced a similar catastrophe 74,000 years ago, in which a supervolcano caused a global winter.

Mud Volcanoes. These volcanoes are created by secreted liquids and gas. The primary gas released from mud volcanoes is methane. Other components include carbon dioxide and nitrogen. Features of these volcanoes include a steep side, mud cone, and hot springs. Mud volcanoes are located in parts of Asiaand Europe. Within the , mud volcanoes can be found in Alaska and California.

Volcano Activity

The activity of volcanoes varies. An eruption often follows an earthquake. Regions that do not experience earthquakes may endure geological changes that are indicative of an impending eruption. For example, if a large body of water such as a lake or bay shows a significant rise in temperature within a short period, scientists generally begin to monitor the area. Moreover, sudden increase in melted snow along volcano mountains may also detect geological activity. In these circumstances, seismologists or volcanologists are necessary to monitor the mountain, and warn of potential danger.

Volcanoes have a very long lifespan. Volcanologist classify volcanoes as either dormant, active, or extinct. Volcanoes are active when they show signs of a forthcoming eruption. Signs of eruption include increase in earthquakes and gas emission from volcanoes. Active volcanoes may, or may not erupt. Moreover, being active does not guarantee that an eruption is near. Some volcanoes remain active for several years before finally erupting.

Volcanoes are dormant when they show no signs of activity. However, dormant volcanoes could potentially become active and erupt. Because volcanoes have a long lifespan, it is possible for a volcano to remain dormant for hundreds of years. Volcanologist classify extinct volcanoes as ones that are not likely to erupt. For example, a supervolcano located in National Yellowstone Parkhasn’t shown any signs of activity in nearly 70,000 years. However, some scientists are uncertain as to whether this particular volcano is extinct.

Predicting Volcano Eruptions

Accurately predicting a volcano eruption is impossible. Nonetheless, geologist and volcanologist have sophisticated instruments that are intended to warn of possible eruptions. Volcanoes are located throughout the earth. Some volcanoes are located in regions that are heavily populated. In the event of an eruption, people living near a volcano mountain must be warned to evacuate. There are three methods used to help predict a volcano eruption: seismicity activity, gas emission, and ground deformation.

Seismicity: Before a volcano erupts, there will be a change in seismic activity. Regions containing volcano mountains are under constant surveillance. Any change in normal seismic activity due to recurrent earthquakes or tremors is grounds for observation.

Gas emission: As magma rises in a volcano, sulfur dioxide is released into the air. An increase in emission of this gas within a short period is an indicator of a forthcoming eruption.

Ground deformation: Highly active volcanoes will experience a change in slope or tilt. Scientists monitoring the ground and area around the volcano are generally able to detect rapid changes. Ground change is the result of an increase in magma within the volcano.

Effects of Volcanoes

The effects of a volcano depend heavily on the severity of the eruption. Smaller eruptions may cause destruction of plant and wildlife near the mountain. On the other hand, larger eruptions may destroy towns and villages. The steady flow of liquid lava devastates everything in its path. The rise in temperature may cause snow packed mountains to melt which might increase the water level and cause deadly mudslides. The choking ash released into the atmosphere hides the sunlight, and a dark overcast may linger for days. Those who listen to warnings and flee are able to escape devastation. Sadly, many who remained in the danger zone of a volcano eruption have lost their lives

Historical Volcanoes

• Mt. St. Helens (1980) in Washington, killed 35

• El Chichon (1982) in Mt. Pinatubo (1991) in the , killed over 500

• Mt.Vesuvius (79 A.D, 1913, 1944) in