VOLCANOES

Volcanology: The Study of Volcanoes Magma (molten rock) from the earth’s upper mantle, is forced up through fractures between plate boundaries, due to intense heat and pressure.

Volcanoes Lava is magma that has reached the surface.

PARTS OF A VOLCANO

What comes out of a Volcano? Lava Rocks, Ash Gases

There are three main types of volcanoes depending on type of boundary involved:

Cinder Cone Volcanoes Simplest type Contains a single vent. Small - rarely higher than 300m Over time, this builds up a circular or oval-shaped cone, with a bowl-shaped crater at the top.

Cinder Cone Volcanoes Alternating layers of rock and ash and lava (not much lava) very violent, explosive, eruptions.  Tend to be made with one eruption. A cinder cone, also called a scoria cone, is a volcano composed of volcanic cinders (scoria), or small, rough particles of hardened lava. When lava that is highly charged with gas bubbles erupts from a vent under pressure, it tends to shoot straight up into the air.

Sunset Crater, Arizona

Composite Volcanoes (Stratovolcanoes) Steep-sided cone built up by alternating layers (strata) of rock and ash and lava. More than one vent Larger than cinder cones (up to 2,400 m)

Composite Volcanoes: Famously destructive Mt. St. Helens and Rainier in Washington,  Mt. Fuji in Japan,  Mt. Pinatubo in the Philippines, and  Mt. Etna in Sicily.

Shield volcanoes Low, dome-shaped profile Very hot, thin, runny lava Thin, fast flowing lava can flow for many km producing gentle slope Frequent but non- explosive eruptions Found at Hot Spots not at plate boundaries

Shield Volcanoes Found at Hot Spots not at plate boundaries Hawaiian Islands, especially Mauna Loa and Mauna Kea.

Pacific Ring of Fire Region surrounding the Pacific Ocean, where many volcanoes and earthquake activity. total of 452 volcanoes, and has 75% of the Earth's active and dormant volcanoes. Mostly subduction zones

HAZARDS

1. Lava May flow over large areas, destroying everything in its path.

2. Ash Can reach very high altitudes and stay for a long time: block sunlight, causing world temperatures to drop. Can destroy crops and, buildings, clog rivers, damage machines.

First-Ever Ashfall Advisory: The National Weather Service issued the first ashfall advisory for Hawaii on May 17, after ash plumes were released from Kilauea Volcano and rose to elevations of 30,000 feet.

3. Lahar Flow of mud, water, ash and debris that can result when snow-covered volcanoes erupt.

4. Poisonous Gas: Sulfur Dioxide Sulfur Dioxide Plumes: This photo is a view from a plane flying parallel to the trend of fissure eruptions in the East Rift Zone. The white plumes rising through calm air are escaping from fissure eruptions. They are rich in sulfur dioxide gas. 

5. Ground deformation Road Displacement: Ground deformation in the East Rift Zone has produced fissures venting steam and fissures fountaining lava. In this photo road displacement is made especially obvious where it cuts the yellow line on the pavement

6. Avalanche The August 2010 Mt. Meager rock avalanche, showing where the slide originated (arrow, 4 km upstream), its path down a steep narrow valley, and the debris field

7. Earthquakes Earthquake Epicenter Map: This map shows the location of earthquakes that occured between January 1 and May 5, 2018, the date of the magnitude 6.9 event. It shows activity concentrated around the summit crater and across the East Rift Zone.

The town of Squamish is situated approximately 10 km from Mt. Garibaldi. In the event of a major eruption of Mt. Garibaldi, which of the hazards has the potential to be an issue for the residents of Squamish?

Predicting Volcanoes

1. Increase in Seismic Activity will increase in frequency and intensity before a volcano erupts. A volcano’s history, how long since its last eruption and the time span between its previous eruptions, is a good first step to predicting eruptions. If the volcano is considered active, it is currently erupting or shows signs of erupting soon. A dormant volcano means there is no current activity, but it has erupted recently. Finally, an extinct volcano means their is no activity and will probably not erupt again. Active and dormant volcanoes are heavily monitored, especially in populated areas.

2. Increase in Temperature Satellites can record the surface temperatures at and around volcanoes.  As magma rises, the surface temperature of the volcano may increase.  Therefore, an increase in surface temperature can indicate that an eruption is likely. A volcano’s history, how long since its last eruption and the time span between its previous eruptions, is a good first step to predicting eruptions. If the volcano is considered active, it is currently erupting or shows signs of erupting soon. A dormant volcano means there is no current activity, but it has erupted recently. Finally, an extinct volcano means their is no activity and will probably not erupt again. Active and dormant volcanoes are heavily monitored, especially in populated areas.

3. Increased Amount of Gases Released Just before an eruption, many volcanoes give off more gas.  The composition of the gas may also change before an eruption.  A volcano’s history, how long since its last eruption and the time span between its previous eruptions, is a good first step to predicting eruptions. If the volcano is considered active, it is currently erupting or shows signs of erupting soon. A dormant volcano means there is no current activity, but it has erupted recently. Finally, an extinct volcano means their is no activity and will probably not erupt again. Active and dormant volcanoes are heavily monitored, especially in populated areas.

4. Bulging of surface of volcano As magma rises before an eruption, it can cause the Earth’s surface to swell.  The side of a volcano may even bulge.  Scientists can use an instrument called a tiltmeter to measure the slope of the volcano’s sides.  Changes in the slope can indicate that an eruption is likely. A volcano’s history, how long since its last eruption and the time span between its previous eruptions, is a good first step to predicting eruptions. If the volcano is considered active, it is currently erupting or shows signs of erupting soon. A dormant volcano means there is no current activity, but it has erupted recently. Finally, an extinct volcano means their is no activity and will probably not erupt again. Active and dormant volcanoes are heavily monitored, especially in populated areas.

Assignment: Volcano Comic Strip Comic strip illustrating: The warning signs of a volcano about to erupt The type of eruptive materials that come out The Hazards the nearby community is in danger of.

Active Volcanoes An active volcano is a volcano that has had at least one eruption during the past 10,000 years. Either erupting or dormant. There are about 1,500 potentially active volcanoes worldwide, aside from the continuous belt of volcanoes on the ocean floor. About 500 of these have erupted in historical time. Many of these are located along the Pacific Rim in what is known as the 'Ring of Fire.‘ There are currently three active volcanoes in Hawaii. On Hawaii Island you'll find Maunaloa and Kilauea in Hawaii Volcanoes National Park. Maunaloa last erupted in 1984 and Kilauea has been continuously erupting since 1983. Loihi is located underwater off the southern coast of Hawaii's Big Island.

Extinct Volcano Has NOT erupted in last 10,000 years NOT expected to erupt again any time soon. Dormant: Mount Rainier and Mount Fuji Extinct:  Aconcagua in Argentina, Mount Kenya in Kenya, Mount Ashitaka in Japan and Mount Buninyong in Australia. Extinct volcanoes have been inactive for a long period of time and are considered unlikely to erupt again.