VOLCANOES. What they are and how they work? Anna Reamer, Sheena Hollingsworth and Rachel West

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1 VOLCANOES What they are and how they work? Anna Reamer, Sheena Hollingsworth and Rachel West Introduction to Physical Science EMPACTS Northwest Arkansas Community College Bentonville, AR C. Dianne Phillips, Professor

2 A volcano is a mountain with a central vent for gases and lava to escape. During a volcanic eruption, hot gases and rocks flow or burst out of the volcano. The word Volcano comes from the Roman God of Fire, Vulcan.

3 WHAT CAUSES A VOLCANO TO ERUPT Deep inside Earth, between the Molten iron core and the thin crust at the surface, there is a solid body of rock called the mantle. When rock from the mantle melts, it moves to the surface through the crust, and releases pent up gases, it erupts.

4 DIFFERENT STAGES OF VOLCANOES Scientists have categorized volcanoes into three main categories: Active Dormant Extinct An active volcano is one which has recently erupted and there is a possibility that it may erupt soon. A dormant volcano is one which has not erupted in a long time but there is a possibility it can erupt in the future. An extinct volcano is one which has erupted thousands of years ago and there s no possibility of eruption.

5 VOLCANOES AROUND THE WORLD

6 FUN FACTS ABOUT VOLCANOES There are volcanoes on the ocean floor that create new sea floor. Volcanoes tell us what is inside the Earth's crust. Magma is molten rock inside the volcano and lava is when the molten rock comes out of the volcano. The Ring of Fire is a ring of volcanoes that circle the Pacific Ocean. In order for a volcano to erupt, it must be over a hot spot. Over 75% of the world's volcanoes are located in the Ring of Fire. Volcanoes can form over mantle plumes which are areas of hot rock under the surface of the Earth. PACIFIC OCEAN An erupting volcano can cause other natural disasters such as earthquakes and tsunamis to occur. Eruptions are what cause a volcano to get bigger. There are three different categories of volcanoes: active, dormant, and extinct. An extinct volcano is one that has not erupted in a very long time and is not expected to ever erupt again. Earth has over 1500 active volcanoes. The largest active volcano is the Mauna Loa in Hawaii which is over 13, 600 feet above sea level. Ninety percent of the world's earthquakes occur along the Ring of Fire. Mount Fuji is the tallest mountain in Japan and is also a dormant volcano.

7 EVERYTHING YOU NEED TO KNOW ABOUT A VOLCANO The largest active one is Mauna Loa, in Hawaii. The most active volcano is Kilauea, also in Hawaii. Most of the earth's volcanoes are located around the Pacific Ocean. The Pacific Ocean is where most of the Earth's subduction zones are found. When hot rocks, called magma, and gases break through the planet's crust, an eruption occurs The buildup of ash and lava flows around the eruption hole (or vent) makes a volcano. The temperature of a volcano depends on its activity. Volcanoes make many different types of rocks. We know of at least 1,500 active volcanoes around the world. About 500 million people live close to active volcanoes.

8 WHY VOLCANOES ARE GOOD FOR THE EARTH Provides nutrients to the surrounding soil. Volcanic ash often contains minerals that are beneficial to plants, and if it is very fine ash it is able to break down quickly and get mixed into the soil. Volcanic slopes are often inaccessible Thus they can provide refuges for rare plants and animals from the ravages of humans and livestock. volcanic gases are the source of all the water (and most of the atmosphere) that we have today. The process of adding to the water and atmosphere is pretty slow, but if it hadn t been going on for the past 4.5 billion years or so we d be pretty miserable.

9 Volcanoes have done wonderful things for the Earth. They helped cool off the earth removing heat from its interior. Volcanic emissions have produced the atmosphere and the water of the oceans. Volcanoes make islands and add to the continents.

10 WITHOUT VOLCANOES EARTH WOULD END UP LIKE MARS