How are volcanoes formed?


How are volcanoes formed?


The Earth’s surface consists for huge plates that fit together like a jigsaw puzzle.  These plates float on a liquid-like layer called the mantle. These large tectonic plates are in very slow but constant motion. Sometimes these plates move toward each other and sometimes they’re moving apart. The friction causes earthquakes and volcanic eruptions near the edges of the plates.

Periodically, a tectonic plate will sink down into the mantle layer and become so hot that the rock melts. Scientists call this material magma. This molten rock eventually makes it way to the surface through cracks.  When it reaches the surface, we call it lava. When layer after lava builds up a volcano is formed.

There are various types of volcanoes, depending on what kinds of material make up the lava, the amount of gas trapped in the lava, and how much pressure builds up. When the molten rock moves to the surface through the Earth’s crust, and releases the pent-up gases, volcanoes erupt.

Volcanoes occur most often at plate boundaries. The most common is the Ring of Fire, a horseshoe shaped string stretching from the western side of South America, western side of North America, across the Bering Sea, down to Japan, Philippines, and into Southeast Asia. This Ring of Fire contains about two-thirds of the active volcanoes today.

The most active volcano in the world is Kilauea in Hawaii. It’s a great tourist attraction with a beautiful Visitor Center.  Adventurous souls can walk over the hot lava ‘till their soles get start to melt and also watch lava fall into the Pacific Ocean. Kilauea, inside Volcano National Park, has been in constant eruption since 1983.

There are more than 1500 active volcanoes on Earth. The one we are most familiar is Mt. St. Helens, in southwest Washington State, that erupted on Sunday, May 18, 1980 killing 57 people. Good portions of Washington and Oregon were covered with ash. Esquire Magazine named Mt. St. Helens  “ash hole of the year”.

Mt. St. Helens has two do-not-miss attractions. The Forest Learning Center has an unforgettable “eruption chamber”, life-like forests, beautiful views of the mountain, and many exhibits.

The Johnson Ridge Observatory, open only during the summer months, has a big-screen movie presentation.  When finished, the curtains open and the visitors enjoys a spectacular view of Mt. St. Helens.  David Johnson, a volcanologist, was camped out on this ridge when the volcano blew. His final words were “Vancouver, Vancouver, this is it”. His body has never been found. The Johnson Ridge Observatory is named in his honor.

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