Volcanos

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A __**VOLCANO**__ is an opening or rupture in the earth's crust, where hot //__magma__//, __//gases//__, and __//ash//__ escape from below the surface is molten rock that is found beneath the Earth's surface check out this video media type="youtube" key="KGmLMbw_1CE" width="389" height="323" align="center"



**The majority of volcanic gases are made up of water vapor (H2O - hydrogen and oxygen elements), about 60% ** **The next greatest amount is carbon dioxide (CO2 - carbon and oxygen elements), about 10-30% ** **Some gases consist of sulfur, as sulfur dioxide (SO2) in high-temperature volcanic gases ** ** or hydrogen sulfide (H2S) in low-temperature volcanic gases ** **Other gases contain nitrogen, chlorine, fluorine, bromine, argon, helium, and even neon **

**a microscoopic view of real volcanic ash** check out this video... media type="youtube" key="12rpq97kEFg" width="425" height="350" align="center"



Volcanoes are formed when the less dense magma from within the Earth's upper mantle is forced to the surface. It flows through an opening called a __**vent**__. At the **__crater__**, it erupts to form lava flows and ash deposits. The volcano erupts because the magma contains water and dissolved gas, that turns to steam and the gas expands, causing a violent eruption.

<span style="color: #808000; display: block; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; text-align: center;">at Divergent Plate Boundaries, seen in Iceland <span style="color: #808000; display: block; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; text-align: center;">and <span style="color: #808000; display: block; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; text-align: center;">at Convergent Plate Boundaries, such as subduction, seen in the Andes of South America <span style="color: #808000; display: block; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; text-align: center;">and <span style="color: #808000; display: block; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; text-align: center;">at Hot Spots (partially melted rock), seen in the Hawaiian Islands

<span style="color: #800000; display: block; font-family: 'Arial Black',Gadget,sans-serif; text-align: center;">Shield Volcanoes <span style="display: block; font-family: Georgia,serif; font-size: 130%; text-align: center;">A build-up of basaltic lava into flat layers form a broad volcano with small sloping sides called a shield volcano. <span style="display: block; font-family: Georgia,serif; font-size: 130%; text-align: center;">Usually //__quiet eruptions__//. Examples of shield volcanoes are the Hawaiian Islands

<span style="color: #800000; display: block; font-family: 'Arial Black',Gadget,sans-serif; text-align: center;">Cinder Cone Volcanoes <span style="display: block; font-family: Georgia,serif; font-size: 130%; text-align: center;">//__Explosive eruptions__// can throw lava and rock high into the air. <span style="display: block; font-family: Georgia,serif; font-size: 130%; text-align: center;">These bits of rock and solidified magma are called **__tephra__**. <span style="display: block; font-family: Georgia,serif; font-size: 130%; text-align: center;">When the tephra falls, it forms a steep-sided volcano are called a cinder cone volcano. An example of a cinder cone volcano is the Paricutin in Mexico



<span style="color: #800000; display: block; font-family: 'Arial Black',Gadget,sans-serif; text-align: center;">Composite Volcanoes or Stratovolcanoes <span style="display: block; font-family: Georgia,serif; font-size: 130%; text-align: center;">The prefix __Strato__- means layer. <span style="display: block; font-family: Georgia,serif; font-size: 130%; text-align: center;">Periods of both quiet and explosive eruptions create layers of lava and tephra, resulting in a Composite Volcano Examples include Mt. Fuji in Japan and Mount Vesuvius in Italy

<span style="color: #800000; display: block; font-family: 'Arial Black',Gadget,sans-serif; text-align: center;">A __Caldera__ is a collapse in a volcano!



<span style="color: #ff3100; display: block; font-family: Georgia,serif; text-align: center;">It is a zone of frequent earthquakes and volcanic eruptions that encircles the basin of the Pacific Ocean. It is shaped like a horseshoe and it is 40,000 km long. It is associated with a nearly continuous series of oceanic trenches, island arcs, and volcanic mountain ranges and/or plate movements. <span style="color: #ff3100; display: block; font-family: Georgia,serif; text-align: center;">90% of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire. <span style="color: #ff3100; display: block; font-family: Georgia,serif; text-align: center;">The Ring of Fire is a direct consequence of plate tectonics and the movement and collisions of crustal plates.



Tsunamis can be created from volcanic earthquakes...

Check this link out! [|Monitoring Actual Volcanic Activity]

<span style="color: #ff0000; display: block; font-family: 'Arial Black',Gadget,sans-serif; font-size: 120%; text-align: center;">LAB ACTIVITY - CLICK VOLCANO BELOW



<span style="color: #ffffff; display: block; font-family: 'Arial Black',Gadget,sans-serif; text-align: center;">Homework:Section 1 Review Questions (Self Check Questions 1-3) page 161Section 2 Review Questions (Self Check Questions 1-4) page 169