Types of Volcanoesnewburyparkhighschool.net/stillwagon/geoscp/Notes/10.1 Volcano T… · Types of...

Types of Volcanoes

• Volcano - mountain formed of lava and/or pyroclastic material

• Conduit (pipe) - carries gas-rich magma to surface

Basic Anatomy of a Volcano

• Crater - depression at summit of volcano

Ship Rock, New Mexico, is a

volcanic neck. Ship Rock consists

of igneous rock that crystallized in

the pipe of a volcano that then was

eroded away.

Types of Volcanoes1) Shield Volcanoes - broad, gently sloping (built from fluid basaltic lavas)

Ex. Mauna Loa in Hawaii

-- Eruptions usually mild & can occur several times

-- Magma has a LOW viscosity

Shield Volcanoes

2) Composite Cones/Stratovolcano – built from both lava flows &

pyroclastic material. Large steep slopes

- Most near Pacific Ocean (Ring of Fire).

- Magma has HIGH viscosity

- Most violent Eruptions!

Pyroclastic Material: Hot

material (from ash size to

bombs size fragments) with

minimal lava that is thrown

from vent and results in the

formation of steep sides

Anatomy of a Composite Volcano

The Eruption of

Mt. St. Helens

Mount St. Helens Before and

After the May 18, 1980, Eruption

3) Cinder Cones - small size, steep slope, (built from pyroclastic material)

-- Tend to be active for a short time, then they go dormant

-- Explosive due to high gas content in Magma

Cinder Cones

Profiles of Volcanic Landforms

Other Volcanic Landforms Calderas - large depressions in volcanoes.

• Formed by collapse of the summit into the emptied magma chamber

• Nearly circular

• Size exceeds 1 km in diameter

Read 10.1 for more information to improve your knowledge of

the content in this lecture and to improve activity/test scores

Composite Cone: Lava Layers,

Crater, Magma Chamber,

Conduit, and Pyroclastic Flow

Layers (pg. 283)

Shield Volcano: Lava Layers,

Crater (summit), Magma

Chamber, and Conduit (pg. 284)

Cinder Cone: Crater, Conduit,

and Pyroclastic Flow Layers

(pg. 285)

DRAW AND LABEL THE THREE FOLLOWING VOLCANO TYPES: