Of all the natural disasters, the flowing lava of a volcano stands as the most iconic. Every year, millions of people travel to volcanic tourist sites so they can gaze upon one of the most exciting and powerful natural events on Earth. While they offer breathtaking sites, they also are packed with the capacity to destroy everything around it. Our history books are filled with stories of civilizations, such as Pompeii, wiped out by volcanic eruptions. Besides the capacity for destruction, the science behind volcano formation and eruptions fail to capture many people’s interest.
Earth has four layers: the crust, the mantle, the outer core, and the inner core. The crust is the outer layer that we see as the surface of the Earth. The crust is composed of 15 to 20 tectonic plates. These plates act much like a broken shell that floats on the mantle. The mantle is composed of hot, molten rock that produces enough heat to move the tectonic plates. Therefore, the surface of the Earth is constantly changing.
Movement of the tectonic plates creates volcanoes. When plates move away from each other, magma can rise to fill the newly created space. This type of movement creates the stereotypical cone-shaped volcanoes. Other times, the plates move towards each other and cause parts of the crust plunge deep into the interior of the mantle. This causes the crust to melt and allows magma to rise between the plates. This type of volcano is commonly found underwater and is shaped like a deep depression in the earth.
Volcanoes can be active, dormant, or inactive. Inactive volcanoes will not erupt. Dormant volcanoes are in a state where they will not erupt anytime soon, but they can erupt in the future. These types of volcanoes are safe to visit and explore. Active volcanoes, in contrast, can erupt at any time. Eruptions are caused by convection currents in the mantle. These currents are repetitive movements within the liquid magma that result from heat. Therefore, seismic activity and earthquakes are common signs that a volcano is active.
When magma reaches the Earth’s surface, it becomes the flowing lava that we commonly associated with volcanoes. However, eruptions do not always involve lava. Many other common eruptions release ash, cinder, or gas. Eruptions may be rather quiet and slow-paced, or they may be dramatically violent and catastrophic. However, the largest and most destructive eruptions are caused by supervolcanoes. The landscape of Yellowstone National Park is a result of this type of eruption. Furthermore, besides crafting landscapes, eruptions can also have sizable cooling effects on the climate lasting for decades.
Where are Volcanoes Found
Volcanoes are very prevalent in many countries. In the United States, we often think of Hawaii or Mount Saint Helens as the volcanic hot spots. However, the United States Geological Survey counted approximately 169 active volcanoes and numerous other inactive and dormant volcanoes across the country. However, most of the volcanoes are located in Alaska, Hawaii, California, and Oregon.
Volcanoes are extremely common in Hawaii, and they often serve as major tourist destinations. Furthermore, every island was created by volcanoes. The big island is home to Mauna Loa, which is the largest active volcano on Earth. Also, the recent eruptions came from a volcano named Kilauea. Kilauea has been spewing lava and creating fissures, which has led to multiple evacuations.
Alaska houses 50 active volcanoes. Most of them are concentrated along the Arc of the Aleutian Islands, which form the Ring of Fire. The Ring of Fire is a known hotspot for volcanic activity. Currently, the Alaska Volcano Observatory issued a yellow alert for Mount Cleveland, which has been releasing ash and scientists have also detected seismic activity.
The Pacific coast has many volcanoes that are scattered from Canada to Mexico. Many are found in the Sierra Nevadas while others are found in the Cascade Range in Oregon and Washington. One of the more famous volcanoes found this area is Mount Saint Helens, which erupted in 1980. In the Cascades, Mount Rainier, a dormant volcano, stands as the tallest mountain in the range. Additionally, Lassen Peak in California erupted in 1917, which created the unique landscape of the Lassen Volcanic National Park.
Similar to Earth, other planets in our solar system are home to volcanoes. Venus and Mars have countless extinct volcanoes, while Jupiter, Saturn, and Neptune have many active volcanoes that NASA scientists have documented.
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Pictures: Featured Image: https://pixabay.com/en/new-zealand-volcano-crater-3018634/, https://commons.wikimedia.org/wiki/File:Tectonic_plates_projection_demo.jpg, https://upload.wikimedia.org/wikipedia/commons/0/08/Convection.gif, https://pixabay.com/en/volcano-erupting-landscape-scenic-1056526/
Resources: https://www.ready.gov/volcanoes, https://spaceplace.nasa.gov/volcanoes2/en/, https://www.nytimes.com/2018/05/14/us/us-active-volcanoes-hawaii.html, https://oceanservice.noaa.gov/facts/tectonics.html