Volcanoes pt. 1

GEOGRAPHY 12

Volcanoes and Volcanic Landforms

TEXTS Videos

Knapp Worral pp. 6 - 22 Volcanic Landforms of B.C.

Smythe Brown pp. 99 - 108 Earth Alive - Volcanism

Physical Geology pp. 169 - 195 The Volcano Watchers

1. Explain how the folowing terms differ:

LAVA vs. MAGMA

Lava is thick and reaches the earths surface, whereas magma is the molten rock inside the earth which is a little thinner than lava.

DORMANT vs. EXTINCT volcanoes

Dormant volcanoes are inactive, but not extinct. There is still a chance that it may erupt in the future, whereas extinct volcanoes are completely incapable of future eruptions.

INTRUSIVE vs. EXTRUSIVE Volcanism

An intrusive volcano is one which erupts INSIDE the earth. An extrusive volcano has an opening on the earths surface- such as a rift or a cone shaped mountain.

VOLCANOES vs. HOT SPOTS

A volcano has an opening above sea level, such as a composite volcano. A hot spot is where magma pushes its way through the crust to erupt on the sea floor or the ground of the earths crust, which creates a sheild volcano.

2. Explain where volcanoes tend to be located.

Volcanoes tend to be located at the edges of tectonic plates. When a plate is converging and creating a cone-shaped volcano, sometimes lava gets pushed up through the neck of the volcano. At divergent plate boundaries, where the plates are seperating and creating a trench, lava may bubble up, or when one plate is subducting under another, a rift volcano may occur.

3. What and where is the "RING OF FIRE"?

The ring of fire is located in the Pacific, stretching from New Zealand, along the Eastern Edge of Asia, North across some Alaskan Islands and South along the coast of North and South America.

4. Complete the following chart for the 3 main types of volcanoes:

example/

volcano type appearance composition location

Composite /cone shaped/ built up of solidified lava and rock sediments/Subduction zones/ Mount Rainier

Sheild/ massive, broad, gently sloped dome/ build up of hot spot lava/ seafloor, divergent zones/ Hawaii

Compound/ two or more vents/ multiple eruptions from sides, build up of ash and solid lava/ Along plate boundaries/ Homa Mountain, Kenya

5. Define the following terms and create an original diagram showing all of the features.

dike – sheet intrusion that cuts across massive rock formations or compositions.

sill – flat, horizontal mass of igneous rock in between two layers of older sedimentary rock formations.

laccolith – an intrusion of igenous rock (molten magma at the time) in between two layers of sedimentary rock. This intrusion pushes the overlying rock up, creating a dome-like appearance on the crust of the earth.

batholith – A large mass of igenous rock believed to have solidified beneath the earth.

pipe (neck) – The throat inside volcanoes that brings the lava to the surface.

geyser – A spring that discharges hot water and steam.

6. Using the PHYSICAL GEOLOGY text complete the following chart:

HAZARD DANGER POSSIBLE SOLUTION ?

lava flow/ it’s fast, can burn anything./ Run, don’t live near volcanoes, use ocean water to spray onto oncoming lava.

Pyroclastics/ cinders, ash, gas./ Create a synthetic winter, block sun./ Nothing. Don’t live near a volcano.

Nuee Ardentes( pyroclastic flows)/ flow of hot gas, rock and ash./ Get out of it’s way.

Lahars/ Landslide flow of hot mud, water and pyroclastics/ It’s very fast, run.

toxic gases/ The toxic gases released from a volcano/ stay away from the opening of a volcano.

steam explosions/ sometimes accompanied by pyroclastics, toxic gases/ don’t live near a volcano.