Chapter 13 Volcanoes

Volcanoes Volcanoes – places where magma breaks through onto the surface of the earth Common along plate boundaries

Building a Volcano 1. Magma collected in chambers below earth’s surface 2. Pressure build and is pushed through a vent 3. Rock and ash fall around opening 4. Over time a cone is built

Many located along subduction zones

Island Arcs Island Arcs – string of volcanic islands

Types of Volcanoes Tall and pointy Small and long Sticky lava Not sticky lava

Types of Volcanoes Composite – tall and pointy Sticky lava Formed by alternating quiet and explosive eruptions

Felsic Lava Rich in light colored silicate material Cooler and stickier Gases cannot escape

Pyroclastic Material Fragments of rock from an eruption Volcanic Ash Lapilli – “Little stones” Volcanic Bombs Volcanic Blocks

Types of Volcanoes Shield – long sloping layers Quiet eruptions Fluid lava

Mafic Lava Rich in magnesium and iron Dark Gases are able to escape Quiet eruptions