Physical Science 101

Location of Volcanism

Where are most active volcanoes found?
Other locations?

Typical Eruption Sequence



Conical or dome-shapes landforms - built from eruption of lava flows and/or pyroclastic materials
Magma rises from a magma chamber through a conduit (vent)
Type of volcano depends on:

Spatter Cones

Small basalt cones - (only a few meters tall)
Built on top of active pahoehoe lava flows.
Spatter Cone Example 1
Spatter Cone Example 2

Cinder Cones (a.k.a. Scoria Cones)

Cone-shaped pile of loose cinders ((scoria) erupted from a central vent.
Eruption craters, Lava flows
Cinder Cone Example 1
Cinder Cone Example 2
Cinder Cone Example 3
Cinder Cone Example 4
Cinder Cone Example 5
Cinder Cone Example 6

Shield Volcanoes

Shallow slopes with relatively flat tops built from basalt, pahoehoe lava flows (look like a shield lying on ground)
Largest volcanoes in the world and Solar System
Shield Volcano Example 1
Shield Volcano Example 2
Shield Volcano Example 3
Shield Volcano Example 4

Stratovolcanoes (a.k.a. Composite Cones)

Conical volcano of andesite, dacite or rhyolite flows and pyroclastic deposits
Violent eruption - due to gas content and high viscosity magma
Ash deposits can be extensive
Stratovolcano Example 1
Stratovolcano Example 2
Stratovolcano Example 3
Stratovolcano Example 4
Stratovolcano Example 5
Stratovolcano Example 6
Stratovolcano Example 7


Steep-sided domes/piles of andesite, dacite or rhyolite lava flows (viscous - low gas)
Endogenous domes - lava builds the dome from the inside
Exogenous domes - lava builds the dome by flows on the surface
Dome Example 1
Dome Example 2
Dome Example 3
Dome Example 4
Dome Example 5
Dome Example 6
Dome Example 7

Other Volcanic Features

Flood Basalt – large volume fissure eruptions of basalt lava flows.
Flood Basalt Example 1
Flood Basalt Example 2
Flood Basalt Example 3

Caldera – magma chamber collapse structures
Caldera Example 1
Caldera Example 2

Sea Floor Volcanism – mid-ocean ridge, seamounts, guyots

Hot Springs – magma heated water and geysers