Download VOLCANOES

How does a volcano erupt?
VOLCANOES AND
PLATE TECTONICS
VOLCANIC
ERUPTIONS
VOLCANIC
LANDFORMATIONS
RING OF FIRE
 One major belt of volcanoes. It includes the many
volcanoes that rim the Pacific Ocean.
ISLAND ARC
 Many volcanoes form near converging plate
boundaries, where two oceanic plates collide.
 Sometimes these volcanoes create a string of
islands called an island arc.
 Volcanoes also occur where an oceanic plate is
subducted beneath a continental plate.
ISLAND ARC
HOT SPOT
FORMATION OF A VOLCANO
SUBDUCTION
SHIELD VOLCANO
CINDER-CONE VOLCANO
COMPOSITE VOLCANO:Cotopaxi
Dormant Volcano. Cayambe
Island Formation. Plume Volcanism
Type of Lava: Pahoehoe
Type of Lava: Aa
Types of Lava: Aa
 Aa flows are emitted from the vent at high rates
ranging to 50km an hour, often with much lava
fountaining. They are characteristic of viscous
magmas.
 Aa flows are animated with sporadic bursts of energy.
They may push down houses, walls and forests.
However, the hallmark of aa lava flows is the very
rough surface it produces when it cools and solidifies.
Lava explosion hits the water in
Hawaii
Pyroclastic Flow
Pyroclastic Flow
Volcanic Landformations:Caldera
Lava Plateau. Stromboli. Italy.
Crater. Erta Ale. Ethiopia
Erta Ale. Ethiopia
Parts of a Volcano
Parts of a Volcano
Volcanic Neck
 Magma hardens in a volcano’s pipe and the
surrounding rock later wears away.
Volcanic Neck
Dikes
 Magma that forces itself across rock layers and
hardens.
Dike
Sills
 Magma that squeezes between horizontal rock layers
and hardens.
Dome Mountains
 Forms when uplift pushes a large body of hardened
magma towards the surface, which eventually will
become expose.
Dome Mountains
Batholiths
 Mass of rock form when a large body of magma cools
inside the crust. Igneous intrusive ( plutonic)
Batholiths