Volcanoes

Volcanoes• There are two main types of volcano:

― Shield volcanoes― Composite/ stratovolcanoes

Volcano Lava type Viscosity Gas

content Lava flow Tectonic setting

Shield Basaltic Low Low Flat, thin flows Divergent

Composite/ stratovolcano Andesitic Moderate

to high HighTravels short

distances, blocky

Convergent (O-O and

C-O)

Shield volcanoes

• Short and broad• Not often explosive• Often found at hot

spots or divergent plate boundaries

(USGS, public domain)

Examples of shield volcanoes

Mauna Kea seen from the summit of Mauna Loa (Nula666 2010, Wikimedia Creative Commons)

Pahoehoe toe lava from Kilauea (Hawaii Volcano Observatory / USGS 2003, public domain)

Stratovolcanoes

• Tall and cone-shaped• Can be very explosive• Often found at

subduction zones

(USGS, public domain)

Examples of stratovolcanoes

Osorno, Andes (littletroll 2006, Wikimedia Creative Commons)

Fuji, Japan (松岡明芳 2013, Wikimedia Creative Commons)

Mt Merapi and 6 other volcanoes on Java (B Werner 2013, public domain)

(USGS, public domain)

References• Tompkins, D.E. (Ed.), 2011, Exploring Earth and

Environmental Science Stages 1, 2 and 3, Earth Science Western Australia