Most but not all volcanoes are located on

Most (but not all) volcanoes are located on plate boundaries. 3 locations

Locations of Volcanoes 1. Subduction zones 2. Spreading centers 3. Hotspots

Volcanic Eruptions

• Hawaiian – Creates shield volcanoes – Least explosive • Strombolian – Creates cinder cones • Vulcanian – Creates strato-volcanoes • Plinian – Most explosive – Often creates calderas or craters

Hawaiian Eruptions • Fluid basalt • Can travel kilometers before cooling and hardening • Lava fountaining • Non-explosive http: //current. com/1 i 4 bm 4 c

Strombolian Eruptions • Fluid basalt or andesite • Bubbles accumulate and rise to the top • Short distinct explosions caused by bursting gas bubbles • Slightly explosive http: //www. flickr. com/photos/roel/2596553511/

Vulcanian Eruptions • Viscous andesite or rhyolite • Viscosity does not allow gas to escape • Fragmentation and explosion of a plug of lava • Short but violent

Plinian Eruptions • • Very viscous rhyolite Fragmentation of gassy magma Largest and most violent Can obliterate the entire top of a mountain • Destructive!

Key Points • Types of volcanic eruptions? – Hawaiian 4 3 – Strombolian 2 – Vulcanian 1 – Plinian • Number them most to least explosive (1 being most explosive, 4 least)

Pavlof Volcano in Alaska, seen from aboard the orbiting ISS, on May 18, 2013.