Volcanoes Liquid Hot Magma. Tungerahua Volcano, Ecuador Talk about this volcano when it erupted and what it is doing right now. Tungerahua Volcano, Ecuador Picture by Alcinoe Calahorrano Liquid Hot Magma.

Volcano Stats Definition of Volcano Number of active volcanos = ? Mountain that forms when molten rock (magma) is forced to the Earth’s surface Number of active volcanos = ? 20 erupting right now (50-60/year) (160/decade) Number of volcanologists = 1,500 MASS, DENSITY, AND ESCAPE VELOCITY The Earth's mass is about 5.98 x 1024 kg. The Earth has an average density of 5520 kg/m3 (water has a density of 1027 kg/m3). Earth is the densest planet in our Solar System. To escape the Earth's gravitational pull, an object must reach a velocity of 24,840 miles per hour (11,180 m/sec).

Nonexplosive Eruptions Volcanic Eruptions Lava flow Lava fountain Nonexplosive Eruptions Explosive Eruptions What is Lava? -magma that flows onto the Earth’s surface

Volcano Model Demonstration

Vents Volcanoes form around vents that release magma onto the Earth’s surface. Lava Magma chamber

The Composition of Magma Determines whether it is explosive or not! water High water content More likely to be !!! High content More likely to be !!! Why? Silica has a thick, stiff consistency Flows slowly Tends to Harden in the volcano’s vent EXPLOSIVE silica EXPLOSIVE The Earth is made of many different and distinct layers. The deeper layers are composed of heavier materials; they are hotter, denser and under much greater pressure than the outer layers. Core: The Earth has a iron-nickel core that is about 2,100 miles in radius. The inner core may have a temperature up to about 13,000°F (7,200°C = 7,500 K), which is hotter than the surface of the Sun. The inner core (which has a radius of about 750 miles (1,228 km) is solid. The outer core is in a liquid state and is about 1,400 miles (2,260 km) thick.

Explosive Volcano Model Demonstration

Questions a. What physical event causes explosive eruptions? b. Would high water content increase the likelihood of having an explosive eruption? c. Would high silica content increase the likelihood of having an explosive eruption?

What Erupts from a Volcano? Blocky lava Lava can be thick or thin. Pahoehoe Aa Pillow lava

What Erupts from a Volcano? Pyroclastic material Rock fragments created by eruptions magma explodes from volcano and solidifies in the air existing rock is shattered by powerful eruptions EXPLOSIVE Lapilli Volcanic bombs Volcanic blocks Volcanic ash

How do volcanoes affect the Earth? Flows and Fallouts hot ash can flow really quickly Knock down buildings Dam rivers (flooding/drought) Kill crops and livestock Climatic Changes Ash & Gases can block sunlight Drop average global temperature noticeably

Types of Volcanoes Shield volcano- a low profile volcano usually built almost entirely of fluid lava flows. (Resembles a warriors shield laying on the ground) Cinder cone volcano- a steep cone shaped volcano with layers of cinder and pyroclastic ash Composite volcano-  is a conical volcano built up by many layers of hardened lava, tephra, pumice, and volcanic ash

Craters, Calderas, and Lava Plateau From explosions of material out of the vent and the collapse of material back into vent Caldera Much larger depression that forms when magma chamber empties and its roof collapses Lava Plateau Forms when lava erupts from long cracks, or fissures, and spreads out evenly (thousands of km)

What causes volcanoes? The Formation of Magma Mantle rock melts when the temperature increases or the pressure decreases. There are lots of uncertainties about why volcanoes form, because scientists have to rely on models based on rock samples and other data.

What causes volcanoes? Where Volcanoes Form Tectonic Plate Boundaries!!! There are lots of uncertainties about why volcanoes form, because scientists have to rely on models based on rock samples and other data. ~75% world’s active volcanoes in Ring of Fire

What causes volcanoes?

What causes volcanoes? Hot Spots- are places within the mantle where rocks melt to generate magma. (Basically, a hole in the lithosphere that allows magma to reach the surface as a volcano) 

How do volcanologists predict eruptions? Measuring Small Quakes Before eruption, increase in number & intensity Measuring Slope Bulges may form with magma (tiltmeter) Measuring Volcanic Gases Outflow of volcanic gases Sulfur dioxide, carbon dioxide Measuring Temperature from Orbit Measure changes in temperature over time

You should not be a Volcanologist if…. You don’t like hiking, backbacking, rockclimbing, etc. You are not interested in experiencing extreme temperatures and heights. If you don’t like to travel to incredible places and see breathtaking views of the world. Robert McGimsey USGS A. Ozerov

Parts of a Volcano